JP2011211531A - Imaging device - Google Patents

Abstract

An object with large movement can be appropriately set as a tracking target while preventing a decrease in tracking accuracy of the object.
A CPU of a digital camera switches an AF function setting from a normal AF mode to an automatic tracking AF mode in response to selection of a subject to be tracked by a touch operation. When the automatic tracking AF mode is set, the CPU instructs the motion detection unit to execute the motion detection process, and causes the motion detection unit to calculate a motion amount indicating the magnitude of the motion of the subject. When the motion amount is input from the motion detection unit, the CPU determines whether or not the motion amount is equal to or greater than a predetermined value. When the CPU determines that the amount of movement is equal to or less than the predetermined value, the CPU executes the tracking target setting process after performing AF. On the other hand, if the CPU determines that the amount of motion is greater than or equal to a predetermined value, the CPU executes the tracking target setting process without performing AF.
[Selection] Figure 6

Description

  The present invention relates to an imaging apparatus having a function of performing tracking processing for automatically tracking a predetermined subject.

  2. Description of the Related Art An imaging apparatus that performs contrast type autofocus (hereinafter referred to as AF) is known. In contrast-based AF, an AF evaluation value corresponding to contrast is calculated from a part of an image (hereinafter referred to as an AF area) of a captured image obtained by an image sensor, and the focus lens is located at a position where the AF evaluation value is the highest. The lens is automatically focused by moving.

  The AF area is generally fixed at the center of the shooting range or at an arbitrary position designated by the user. However, when the AF area is fixed in this way, when the subject to be focused on moves, the subject may be out of the AF area and the desired subject may not be focused as expected. is there.

  In order to prevent such a problem, for example, Patent Document 1 proposes an imaging apparatus that automatically tracks the movement of a predetermined subject and moves the AF area by following the subject. In Patent Literature 1, when a user specifies a desired subject by operating an operation unit, the subject image is stored as a reference pattern image, and pattern matching processing is performed based on the reference pattern image. Thus, a location that matches the reference pattern image is detected from the captured image acquired thereafter. Then, the AF area is made to follow the subject desired by the user by moving the AF area to a position corresponding to the detected location. In this way, if the AF area is made to follow the subject to be photographed, the subject can be appropriately focused even when the subject moves.

JP 2006-184742 A

  As described above, when performing automatic tracking of an object by pattern matching processing, if the image set as the reference pattern image is too defocused, it will be difficult to detect matching points by pattern matching processing, and tracking will continue. It may not be possible. As described above, the defocus of the reference pattern image causes a decrease in the tracking accuracy of the subject.

  In order to prevent this, it is necessary to perform AF once before setting the reference pattern image and focus on the subject to be tracked. However, if AF is performed when the movement of the subject is large, the subject that is desired to be tracked moves out of the range that can be set as the reference pattern image as the subject moves during this time, and a different subject becomes the reference pattern image. There is a problem that the subject desired by the user is not appropriately set as the reference pattern image, such as being set. As described above, when the movement of the subject is large, even if AF is performed, the subject that is desired to be tracked is not necessarily focused properly. For this reason, in an imaging apparatus that automatically tracks a predetermined subject, it is desired that a subject with large movement can be appropriately set as a tracking target while preventing a decrease in tracking accuracy of the subject.

  The present invention has been made in view of the above problems, and an object thereof is to appropriately set a subject with large movement as a tracking target while preventing a decrease in tracking accuracy of the subject.

  In order to achieve the above object, the present invention includes a photographic lens capable of adjusting a focus by moving a focus lens in the optical axis direction, and an imaging element that captures a subject image formed by the photographic lens. , By driving the image pickup device, a plurality of time-series continuous image data is acquired, and a function of performing autofocus for automatically focusing the photographing lens, and automatically tracking a predetermined subject In an imaging apparatus having a function of performing a tracking process, a predetermined area is extracted from the image data, and a tracking target setting processing unit that sets the area as a tracking target of the tracking process is detected. When the movement detection unit and the tracking target setting processing unit set the tracking target, the movement detection unit detects the movement of the subject. When the movement is small, the tracking target setting processing unit is caused to execute the setting of the tracking target after performing autofocus, and when the movement is large, the tracking target setting processing unit is not subjected to autofocusing and the tracking target setting processing unit A setting control means for executing setting of a tracking target is provided.

  It is preferable that the motion detection means detects the motion of the subject based on the image data.

  The photographing lens has a main body provided on the front surface and a sensor for detecting the movement of the main body, and the movement detecting unit detects the movement of the subject based on the detection result of the sensor. Also good.

  The setting control means automatically detects when the movement is small in both the detection of the movement of the subject based on each image data and the detection of the movement of the subject based on the detection result of the sensor. After performing the focus, the tracking target setting processing unit executes the setting of the tracking target, and the setting control unit detects the movement of the subject based on the image data and the detection result of the sensor. It is preferable to cause the tracking target setting processing unit to execute the setting of the tracking target without performing autofocusing when it is detected that the movement is large by either of the detected movements of the subject.

  AF evaluation value calculation means for calculating an AF evaluation value based on the image data, and the setting control means, when the tracking target setting processing means sets the tracking target, the current position of the focus lens When the AF evaluation value is calculated by the AF evaluation value calculation means, and the AF evaluation value is equal to or less than a predetermined value, the tracking target setting processing means performs the setting of the tracking target after performing autofocus, It is preferable to have a control mode in which the tracking target setting processing unit performs the setting of the tracking target without performing autofocus when the value is equal to or greater than a predetermined value.

  The setting control means sets the tracking target in the tracking target setting processing means without performing auto focus when the AF evaluation value at the current position of the focus lens is a predetermined value or more and the movement of the subject is large. When the AF evaluation value is less than or equal to a predetermined value and when the movement of the subject is small, it is preferable that the tracking target setting processing unit execute the setting of the tracking target after performing autofocus. .

  Reference information storage means for storing, as reference information, various information related to the shooting scene at the time when an operation that seems to be in focus or close to focus is performed, and the reference information Scene change check processing means for determining whether or not the shooting scene has changed based on the reference information stored in the storage means, and the setting control means includes the tracking target setting processing means for the tracking target When performing the setting, the scene variation check processing unit is caused to perform the determination, and when it is determined that there is no variation in the shooting scene, the tracking target setting processing unit is configured to set the tracking target without performing autofocus. Control to cause the tracking target setting processing means to execute the setting of the tracking target after performing autofocusing when it is determined that there is a change in the shooting scene. It is preferred to have the like.

  The setting control means causes the tracking target setting processing means to execute the setting of the tracking target without performing auto focus when there is no change in the shooting scene and the movement of the subject is large, and there is a change in the shooting scene. In this case, and when the movement of the subject is small, it is preferable to cause the tracking target setting processing means to execute the setting of the tracking target after performing autofocus.

  It is preferable that the reference information storage unit stores, as the reference information, any one of a zoom lens position of the photographing lens, a result of face detection processing, a photometric value, a position of the focus lens, and an AF evaluation value.

  Before the tracking target setting processing means sets the tracking target, the tracking target setting processing means includes an AF operation setting means for setting whether or not to perform autofocus, and the setting control means includes the tracking target setting processing means When setting the tracking target, the setting by the AF operation setting unit is confirmed, and if auto-focusing is set, the tracking target setting processing unit sets the tracking target after performing auto-focusing. It is preferable to have a control mode that causes the tracking target setting processing means to execute the setting of the tracking target without performing auto focusing when it is set not to perform auto focusing.

  In the setting of the AF operation setting means, there is a mode for automatically determining whether or not to perform autofocus, and when the setting control means is set to automatically determine autofocus, It is preferable to determine whether or not to perform autofocus based on the detection result of the motion detection unit, the AF evaluation value at the current position of the focus lens, or the determination result of the scene variation check processing unit.

  The setting control unit causes the AF evaluation value calculation unit to calculate an AF evaluation value at the current position of the focus lens when the AF operation setting unit is set not to perform autofocus, and the AF evaluation value is calculated. If the value is less than or equal to a predetermined value, it is preferable to issue a warning indicating that the subject is out of focus.

  The setting control unit causes the scene variation check processing unit to determine whether or not the shooting scene has changed when the AF operation setting unit is set to perform autofocus, and if there is no variation in the shooting scene. When it is determined, it is preferable to perform notification indicating that autofocus can be omitted.

  In the present invention, when the tracking target setting processing unit sets the tracking target, the motion detection unit detects the movement of the subject. When the movement is small, the tracking target setting processing unit performs tracking after performing autofocus. When the target setting is executed and the movement is large, the tracking target setting processing unit is set to execute the tracking target setting without performing autofocusing, so that the tracking accuracy of the subject is prevented from being lowered and the movement of the subject is reduced. A large subject can be appropriately set as a tracking target.

It is a front perspective view of a digital camera. It is a rear view of a digital camera. It is explanatory drawing which shows roughly the operation | movement at the time of automatic tracking AF mode. 1 is a block diagram schematically showing an electrical configuration of a digital camera. It is explanatory drawing which shows the concept of a feature point tracking. It is a flowchart which shows the outline of the operation | movement procedure of a digital camera. It is a flowchart which shows the outline of the procedure of a motion detection process. It is a flowchart which shows the outline of the procedure of the motion detection process by area matching. It is explanatory drawing which shows the concept of area matching. It is a flowchart which shows the outline of the procedure of the motion detection process by preparation of a brightness | luminance difference image. It is explanatory drawing which shows the concept of preparation of a brightness | luminance difference image. It is a block diagram which shows the example which provided the gyro sensor. It is a flowchart which shows the outline of the operation | movement procedure at the time of providing a gyro sensor. It is a flowchart which shows the example which performs the motion detection process by a sensor, and the motion detection process by an image process. It is a flowchart which shows the example made to determine whether the present AF evaluation value is more than predetermined value before a motion detection process. 6 is a flowchart illustrating an example in which whether or not to perform AF is determined only by whether or not a current AF evaluation value is a predetermined value or more. It is a block diagram which shows the example which provided the scene variation check process part. It is a flowchart which shows the example which performed the scene change check process before a motion detection process. It is a flowchart which shows the outline of a scene change check process. 10 is a flowchart illustrating an example in which whether or not AF is performed is determined only by scene variation check processing. It is a block diagram which shows the example which provided the setting memory | storage part. It is explanatory drawing which shows an example of the setting method of AF operation before automatic tracking. It is a flowchart which shows the example which enabled it to reflect a user's setting. It is a flowchart which shows the example which made it determine only by a user's setting whether AF is performed. It is a flowchart which shows the example which made it determine whether the present AF evaluation value is more than predetermined value in AF operation OFF mode. It is explanatory drawing which shows an example of the warning with respect to a user. It is a block diagram which shows the example which provided the scene variation check process part and the setting memory | storage part. It is a flowchart which shows the example which performed the scene change check process in AF operation ON mode. It is explanatory drawing which shows an example of the alerting | reporting with respect to a user.

[First Embodiment]
As shown in FIG. 1, the digital camera (imaging device) 2 has a camera body (main body part) 4 formed in a substantially rectangular parallelepiped shape. A lens barrel 11 that holds the photographing lens 10 and a flash light emitting unit 12 that irradiates a subject when performing photographing are provided on the front surface of the camera body 4. On the upper surface of the camera body 4, a release button 14 for instructing shooting, a power button 15 for switching power ON / OFF, and a zoom for performing a zoom operation for changing the magnification of the shooting lens 10 to the wide side or the tele side. A lever 16 is provided.

  The release button 14 is a two-stage push switch. When the release button 14 is lightly pressed (half-pressed), various types of shooting preparation processing such as AF (automatic focus adjustment) and AE (automatic exposure adjustment) are performed. When the release button 14 is further pressed (fully pressed) from this half-pressed state, the digital camera 2 is instructed to perform shooting, and the image signal for one screen on which shooting preparation processing has been performed is converted into image data.

  As shown in FIG. 2, a liquid crystal display 18, a mode selection button 19, and a menu button 20 are provided on the back surface of the camera body 4. The liquid crystal display 18 displays a photographed image, a so-called through image during photographing standby, various menu screens, and the like. The digital camera 2 has a plurality of operation modes such as a still image shooting mode for acquiring a still image, a moving image shooting mode for acquiring a moving image, and a playback mode for reproducing and displaying each acquired image on the liquid crystal display 18. The mode selection button 19 is operated when switching each operation mode of the digital camera 2. The operation mode of the digital camera 2 is sequentially switched according to the pressing operation of the mode selection button 19. The menu button 20 is operated when various menu screens are displayed on the liquid crystal display 18.

  A touch panel 21 (see FIG. 4) is provided on the front surface of the liquid crystal display 18. The touch panel 21 is attached so that the surface thereof is substantially flush with the back surface of the camera body 4. The touch panel 21 detects the position when the surface is pressed with a finger or a dedicated pen.

  In the digital camera 2, the shooting function setting or the like can be performed by pressing the surface of the touch panel 21 with a finger or moving the finger in the pressed state in accordance with the icon or image displayed on the liquid crystal display 18. Various operations such as switching of images to be displayed can be performed intuitively.

  In addition, the AF function of the digital camera 2 includes a normal AF mode in which the AF area 23 (see FIG. 3) is fixed at the center of the shooting range, and a subject selected by the user is automatically tracked. And an automatic tracking AF mode in which 23 is moved following the movement. When the digital camera 2 is set to the still image shooting mode or the moving image shooting mode, the normal AF mode is set. The automatic tracking AF mode is set by selecting an arbitrary subject from the through image displayed on the liquid crystal display 18 after setting the still image shooting mode or the moving image shooting mode to put the digital camera 2 in the shooting standby state. .

  Selection of a subject is performed by touching a subject desired to be tracked from any subject on the through image. For example, as illustrated in FIG. 3, when the frame image 22 including the subjects S1 to S3 is displayed on the liquid crystal display 18 as a through image, and the user wants to execute the automatic tracking AF mode with the subject S1 as a tracking target, A touch operation is performed on a portion corresponding to the subject S1 on the screen.

  When the touch panel 21 detects that the part corresponding to the subject S1 has been touched, the digital camera 2 switches the AF function setting from the normal AF mode to the automatic tracking AF mode in response to the detection.

  When the automatic tracking AF mode is set, the digital camera 2 sets the AF area 23 fixed at the center of the shooting range as shown in FIG. 3A to the touch panel 21 as shown in FIG. According to the detection result, it is moved to the part corresponding to the subject S1. At the same time, the digital camera 2 overlay-displays a target display frame 24 surrounding the subject S1 on the frame image 22, and the target display frame 24 starts the automatic tracking AF mode for the subject S1 as a tracking target. To inform.

  In the automatic tracking AF mode, when the subject S1 moves while the subject S1 is set as a tracking target, the movement is automatically detected by the digital camera 2, and as shown in FIG. The AF area 23 and the target display frame 24 move. Thereby, in the automatic tracking AF mode, even when the movement of the subject is fast, the photographing lens 10 can be quickly focused on the subject. In the automatic tracking AF mode, for example, the tracking target subject is touch-operated again to instruct the end of tracking, or the tracking target subject falls out of the shooting range and falls into a state where tracking is impossible. Canceled.

  As shown in FIG. 4, the photographing lens 10 includes a zoom lens 26 that changes the photographing magnification by moving in the optical axis direction, a diaphragm mechanism 27 that adjusts the amount of light by changing the aperture area, and an optical axis. A focus lens 28 that adjusts the focal point by moving in a direction is provided. A lens driving motor 30 is connected to the zoom lens 26 and the focus lens 28 via a transmission mechanism such as a gear. The zoom lens 26 and the focus lens 28 are moved in the optical axis direction by driving the lens drive motor 30. In addition, a feeding motor 31 is connected to the lens barrel 11. The feeding motor 31 feeds / retracts the lens barrel 11 by transmitting a driving force to the lens barrel 11 via a transmission mechanism such as a gear.

  Each motor 30, 31 is connected to a motor driver 32. The motor driver 32 is connected to a CPU (setting control means) 34 that comprehensively controls the entire digital camera 2, and transmits drive pulses to the motors 30 and 31 based on a control signal from the CPU 34. Each of the motors 30 and 31 rotates and rotates the rotation shaft in accordance with the drive pulse.

  Behind the photographic lens 10, a CCD (imaging device) 36 that images a subject image formed by the photographic lens 10 is disposed. A timing generator (TG) 38 controlled by the CPU 34 is connected to the CCD 36, and the shutter speed of the electronic shutter is determined by a timing signal (clock pulse) input from the TG 38.

  The image data output from the CCD 36 is input to a correlated double sampling circuit (CDS) 40, and output as R, G, B image data that accurately corresponds to the accumulated charge amount of each cell of the CCD 36. The image data output from the CDS 40 is amplified by an amplifier (AMP) 41 and converted into digital image data by an A / D converter (A / D) 42.

  The image input controller 43 is connected to the CPU 34 via the bus 44, and controls each part of the CCD 36, the CDS 40, the AMP 41, and the A / D 42 in accordance with a control command from the CPU 34. The image data output from the A / D 42 is temporarily recorded in the SDRAM 45.

  The image signal processing circuit 46 reads the image data from the SDRAM 45, performs various image processing such as gradation conversion, white balance correction, and γ correction processing, and records the image data in the SDRAM 45 again. The YC conversion processing circuit 47 reads out the image data subjected to various processes by the image signal processing circuit 46 from the SDRAM 45, and converts it into a luminance signal Y and color difference signals Cr and Cb. The liquid crystal driver 48 reads the image data that has passed through the image signal processing circuit 46 and the YC conversion processing circuit 47 from the SDRAM 45, converts it into an analog composite signal, and displays it on the liquid crystal display 18.

  The compression / decompression processing circuit 50 generates a still image file or a moving image file from the image data by converting the image data YC converted by the YC conversion processing circuit 47 into a predetermined file format. The media controller 51 accesses the memory card 52 detachably attached to the media slot, and reads / writes the generated still image file and moving image file.

  Various operating members such as a release button 14, a zoom lever 16, a mode selection button 19, a menu button 20, and a touch panel 21 are connected to the CPU 34. Each of these operation members detects an operation and inputs the detection result to the CPU 34.

  In addition to the above, the bus 44 includes a flash control unit 53, an AE / AWB detection circuit 54, an AF detection circuit (AF evaluation value calculation means) 55, a motion detection unit 56, a tracking target setting processing unit 57, and tracking processing. The unit 58 and the like are connected. The flash control unit 53 causes the flash light emitting unit 12 to emit light according to the flash light emission signal transmitted from the CPU 34.

  The AE / AWB detection circuit 54 calculates a photometric value representing the luminance of the subject based on the integrated value of the luminance signal Y of the image data YC converted by the YC conversion processing circuit 47 and the color difference signals Cr and Cb. The calculation result is transmitted to the CPU 34. The CPU 34 determines the appropriateness of the exposure amount and the white balance based on the photometric value transmitted from the AE / AWB detection circuit 54, and controls the operations of the aperture mechanism 27 and the CCD 36 of the photographing lens 10.

  The AF detection circuit 55 calculates an AF evaluation value in the AF area 23 based on the image data digitized by the A / D 42 and transmits the calculation result to the CPU 34. The CPU 34 causes the AF detection circuit 55 to calculate the AF evaluation values at a plurality of positions while moving the focus lens 28 during the shooting preparation process when the release button 14 is pressed halfway. Then, the photographing lens 10 is brought into focus by moving the focus lens 28 to a position having the highest AF evaluation value. In this way, the CPU 34 performs so-called contrast AF based on the AF evaluation value calculated by the AF detection circuit 55.

  The motion detection unit 56 performs motion detection processing for detecting the amount of motion of the subject based on the image data YC converted by the YC conversion processing circuit 47 under the control of the CPU 34. When the motion detection unit 56 starts the motion detection process in accordance with an instruction from the CPU 34, the motion detection unit 56 first reads out image data after YC conversion from the SDRAM 45. When the image data is read, the motion detection unit 56 uses the frame image 22 indicated by the image data as a reference image, and extracts a plurality of feature points 60 from the frame image 22 as shown in FIG. The feature point 60 is a point that can be easily distinguished from other points in the subject of the frame image 22, and is, for example, a corner having a luminance gradient.

  After extracting each feature point 60, the motion detection unit 56 reads the image data of the next frame after YC conversion from the SDRAM 45, and uses the frame image 22 indicated by the image data as a corresponding image. Then, by using a known method such as template matching, as shown in FIG. 5B, corresponding points 62 corresponding to the respective feature points 60 are obtained from the frame image 22 as the corresponding image.

  After obtaining each corresponding point 62, the motion detecting unit 56 determines each corresponding point 62 based on the position of each feature point 60 on the frame image 22 and the position of each corresponding point 62 corresponding thereto as shown in FIG. A movement vector 64 of the feature point 60 is calculated.

  After calculating each movement vector 64, the motion detection unit 56 groups each movement vector 64 for each object that seems to be the same subject, depending on the position, direction, size, and the like of each movement vector 64. At this time, the motion detection unit 56 deletes the movement vector 64 that seems to be an incorrect correspondence between the feature point 60 and the corresponding point 62.

  Thereafter, the motion detection unit 56 determines the motion of each subject captured in each frame image 22 by obtaining an average motion vector for each motion vector 64 of each group. Then, the motion detection unit 56 determines the average movement vector having the largest size as the representative movement vector.

  As described above, the motion detection unit 56 performs the representative movement indicating the magnitude and direction of the motion of the subject having the largest motion from the image data after YC conversion by tracking the feature points using the feature points 60 and the corresponding points 62. A vector is obtained, the magnitude of the representative movement vector is detected as a motion amount, and the motion amount is input to the CPU 34.

  The tracking target setting processing unit 57 performs a tracking target setting process for setting a tracking target in the automatic tracking AF mode in accordance with an instruction from the CPU 34. When detecting that the automatic tracking AF mode is set via the touch panel 21, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting process. At this time, the CPU 34 inputs the position information detected by the touch panel 21 to the tracking target setting processing unit 57 together with an instruction to execute the tracking target setting process.

  When receiving the instruction to execute the tracking target setting process from the CPU 34, the tracking target setting processing unit 57 first reads the image data after YC conversion from the SDRAM 45. When the tracking target setting processing unit 57 reads the image data, the tracking target setting processing unit 57 performs a known pattern matching process based on the frame image 22 indicated by the image data and the position information input from the CPU 34 together with the execution instruction. The subject selected by the user is specified, and an area corresponding to the subject is extracted from the frame image 22. For example, as shown in FIG. 3, when the user selects the subject S1, the subject S1 is specified by pattern matching processing, and a corresponding region is extracted. Thereafter, the tracking target setting processing unit 57 sets the extracted image as a tracking target, and stores the image in the SDRAM 45 as a tracking target image.

  The tracking processing unit 58 performs a tracking process for tracking the subject set as the tracking target by the tracking target setting processing unit 57 in accordance with an instruction from the CPU 34. After the tracking target setting process by the tracking target setting processing unit 57 is completed, that is, after the tracking target image is stored in the SDRAM 45, the CPU 34 instructs the tracking processing unit 58 to execute the tracking process.

  When receiving an instruction to execute the tracking process from the CPU 34, the tracking processing unit 58 reads the image data after YC conversion and the tracking target image from the SDRAM 45. After performing these readings, the tracking processing unit 58 performs pattern matching processing based on the frame image 22 indicated by the image data and the tracking target image, so that the tracking image 58 most closely matches the tracking target image. Extract regions. After extracting the matching area, the tracking processing unit 58 inputs the position information of the area to the CPU 34 as the tracking result.

  Then, the tracking processing unit 58 repeats the above processing every time image data of the next frame is acquired until the CPU 34 instructs to end, and sequentially stores the position information of the region that most closely matches the tracking target image. To enter. Note that each time a matching area is extracted from each frame image 22, the tracking target image may be sequentially updated as a tracking target image for tracking processing of the next frame.

  Next, the operation of the digital camera 2 configured as described above will be described with reference to the flowcharts of FIGS. When the user performs shooting while setting the digital camera 2 to the automatic tracking AF mode, the user presses the power button 15 to activate each part of the digital camera 2 and then presses the mode selection button 19 to select the still image shooting mode. Alternatively, the moving image shooting mode is selected, and the digital camera 2 is set in a shooting standby state.

  When the digital camera 2 enters the shooting standby state, the CPU 34 controls the TG 38, and the CCD 36 is driven by the timing signal output from the TG 38. The CCD 36 performs imaging in response to the timing signal from the TG 38 and outputs an imaging signal corresponding to the subject image formed by the photographing lens 10.

  The imaging signal output from the CCD 36 is converted into digital image data through the CDS 40, the AMP 41, and the A / D 42. The digital image data is subjected to various image processing in the image signal processing circuit 46 and YC conversion processing in the YC conversion processing circuit 47, and then converted into an analog composite signal in the liquid crystal driver 48. It is displayed on the liquid crystal display 18 as a through image. In this way, the digital camera 2 acquires a plurality of time-sequential image data by driving the CCD 36 and sequentially displays the image data on the liquid crystal display 18 as a through image.

  After the digital camera 2 enters the shooting standby state and a through image is displayed on the liquid crystal display 18, the user selects a desired subject to be set as a tracking target from the subjects included in the through image. Then, setting of the automatic tracking AF mode is instructed by touching the subject on the screen.

  When the touch panel 21 detects that the part corresponding to the predetermined subject has been touched, the CPU 34 of the digital camera 2 switches the setting of the AF function from the normal AF mode to the automatic tracking AF mode in response to the detection. When the automatic tracking AF mode is set, the CPU 34 first moves the AF area 23 fixed at the center of the shooting range to a position corresponding to the detection result of the touch panel 21. Thereafter, the CPU 34 instructs the motion detection unit 56 to execute the motion detection process.

  When the CPU 34 is instructed to execute the motion detection process, the motion detection unit 56 reads the image data after YC conversion from the SDRAM 45, uses the frame image 22 indicated by the image data as a reference image, and starts from the frame image 22. A plurality of feature points 60 are extracted. After extracting each feature point 60, the motion detection unit 56 reads out the image data of the next frame after YC conversion from the SDRAM 45, sets the frame image 22 indicated by the image data as a corresponding image, and the frame image 22 The corresponding points 62 corresponding to each of the feature points 60 are obtained.

  After obtaining each corresponding point 62, the motion detection unit 56 calculates the movement vector 64 of each feature point 60, groups each movement vector 64, and calculates the average movement vector of each group. The largest one is determined as the representative movement vector. Then, the motion detection unit 56 detects the magnitude of the representative movement vector as a motion amount, and inputs the motion amount to the CPU 34.

  When the motion amount is input from the motion detection unit 56, the CPU 34 determines whether the motion amount is equal to or greater than a predetermined value. When the CPU 34 determines that the amount of movement is equal to or less than the predetermined value, the contrast lens AF based on the AF evaluation value of the AF detection circuit 55 is performed to focus the photographing lens 10 on the subject set as the tracking target. Let Thereafter, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting process. On the other hand, if the CPU 34 determines that the amount of movement is equal to or greater than the predetermined value, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting processing without performing AF.

  When the tracking target setting processing unit 57 executes the tracking target setting process in accordance with an instruction from the CPU 34, the tracking target image obtained by setting the subject selected by the user by the touch operation as the tracking target and extracting the area corresponding to the subject. Is stored in the SDRAM 45.

  When the tracking target setting process by the tracking target setting processing unit 57 is completed, the CPU 34 instructs the tracking processing unit 58 to execute the tracking process. At the same time, the CPU 34 generates image data of the target display frame 24 so as to surround the tracking target image, and displays it on the corresponding position on the through image.

  When the tracking processing unit 58 starts tracking processing in response to an instruction from the CPU 34, each time image data of each frame is acquired, the tracking processing unit 58 extracts an area that most closely matches the tracking target image from the frame image 22. Is input to the CPU 34. When the position information is input from the tracking processing unit 58, the CPU 34 moves the AF area 23 and the target display frame 24 displayed on the liquid crystal display 18 to a position corresponding to the position information. Accordingly, when the digital camera 2 is set to the automatic tracking AF mode, the AF area 23 and the target display frame 24 move following the movement of the subject set as the tracking target.

  As described above, in this embodiment, when it is considered that the shooting scene is a shooting scene in which the movement amount is equal to or less than the predetermined value and the subject movement is small (slow), the tracking target setting process is executed after the AF is performed, Is considered to be a shooting scene with a large (fast) subject movement with a predetermined value or more, the tracking target setting process is executed without performing AF.

  In this way, in the case of a shooting scene in which the movement of the subject is small, information about the subject can be accurately acquired, and the accuracy of the tracking process can be improved. Then, in the case of a shooting scene in which the movement of the subject is large, the tracking target setting process can be quickly performed, and the subject that has been moving from the beginning can be appropriately set as the tracking target.

  In the above embodiment, the movement of the subject is detected by the feature point tracking using the feature point 60 and the corresponding point 62, but not limited to this, as shown in the flowchart of FIG. 8 and the explanatory diagram of FIG. The movement of the subject may be detected by area matching. The processing procedure will be described below.

  The motion detection unit 56 reads the image data after YC conversion from the SDRAM 45 when the motion detection process is started in accordance with an instruction from the CPU 34. When the motion detection unit 56 reads the image data, the frame image 22 indicated by the image data is used as a reference image, and the frame image 22 is subjected to grouping using the color of each pixel, a high-frequency component, or the like. As shown in FIG. 9A, a plurality of subject areas 70 indicating portions corresponding to characteristic subjects are extracted from the frame image 22.

  After extracting each subject area 70, the motion detection unit 56 reads the image data of the next frame after YC conversion from the SDRAM 45, and uses the frame image 22 indicated by the image data as a corresponding image. Then, by performing area matching for each subject area 70 on the frame image 22, as shown in FIG. 9B, the corresponding area corresponding to each subject area 70 from the frame image 22 as a corresponding image. 72 is obtained.

  After obtaining each corresponding area 72, the motion detection unit 56, as shown in FIG. 9C, based on the center position of each subject area 70 on the frame image 22 and the center position of each corresponding area 72 corresponding thereto. Then, the movement vector 74 of each subject area 70 is calculated.

  After calculating each movement vector 74, the motion detection unit 56 determines a movement vector 74 having the largest size as the representative movement vector. Then, the magnitude of the representative movement vector is detected as a motion amount, and the motion amount is input to the CPU 34. As described above, the subject area 70 indicating the portion corresponding to the characteristic subject is extracted from the frame image 22 serving as the reference image, and the movement vector 74 of the subject area 70 is calculated by performing area matching. Motion can be detected.

  Furthermore, as shown in the flowchart of FIG. 10 and the explanatory diagram of FIG. 11, the movement of the subject may be detected based on the difference between the reference image and the corresponding image. The processing procedure will be described below.

  When the motion detection process starts in response to an instruction from the CPU 34, the motion detection unit 56 reads the image data after YC conversion from the SDRAM 45, and stores the frame image 22 indicated by the image data as a reference image. After storing the reference image, the motion detection unit 56 reads the image data after YC conversion of the next frame from the SDRAM 45, and stores the frame image 22 indicated by the image data as a corresponding image.

  Thereafter, the motion detection unit 56 obtains a difference between the luminance value of each pixel of the reference image and the luminance value of each pixel of the corresponding image at the position corresponding to the reference value, as shown in FIG. Then, a luminance difference image 76 composed of the difference between the luminance values of these images is created. After creating the luminance difference image 76, the motion detection unit 56 obtains the absolute value of the luminance value of each pixel of the luminance difference image 76, and counts the number of pixels whose absolute value is larger than a predetermined threshold value. Pixels having an absolute value greater than a predetermined threshold are portions where the subject has changed between the reference image and the corresponding image. Therefore, it can be considered that the amount of movement of the subject increases as the count number increases.

  After performing the count, the motion detection unit 56 detects the motion amount using the count number as an index so that the motion amount increases as the count number increases, and inputs the motion amount to the CPU 34. As described above, the movement of the subject can also be detected by obtaining the difference between the luminance values of the reference image and the corresponding image. Note that the method of detecting the movement of the subject using image processing is not limited to the above, and any method that can detect the movement of the subject may be used.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The same functions and configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in FIG. 12, the motion detector 82 of the digital camera 80 of the present embodiment is provided with a gyro sensor 84 that detects the motion of the camera body 4. The gyro sensor 84 is a so-called triaxial gyroscope, detects angular velocities in the three axial directions of the camera body 4 in the height direction, the width direction, and the depth direction as movements of the camera body 4 and outputs a signal corresponding to the movements. .

  The motion detection unit 82 refers to the output of the gyro sensor 84 when the execution of the motion detection process is instructed from the CPU 34, and generates a motion amount indicating the magnitude of the motion of the subject based on the output. In general, when shooting a subject with large movement, the camera body 4 is made to follow the movement (so-called panning) in order to prevent the subject from moving out of the shooting range. Accordingly, the motion detection unit 82 generates a motion amount assuming that the greater the motion of the camera body 4 is, the greater the motion of the subject is. After generating the motion amount, the motion detection unit 82 inputs the motion amount to the CPU 34.

  Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG. When the touch panel 21 detects that a portion corresponding to a predetermined subject has been touched, the CPU 34 of the digital camera 80 switches the setting of the AF function from the normal AF mode to the automatic tracking AF mode in response to the detection. When the automatic tracking AF mode is set, the CPU 34 first moves the AF area 23 fixed at the center of the shooting range to a position corresponding to the detection result of the touch panel 21. Thereafter, the CPU 34 instructs the motion detection unit 82 to execute the motion detection process.

  The motion detection unit 82 refers to the output of the gyro sensor 84 in response to an instruction from the CPU 34 to execute the motion detection process. Based on the output, a movement amount indicating the magnitude of the movement of the subject is generated, and the movement amount is input to the CPU 34.

  When the motion amount is input from the motion detection unit 82, the CPU 34 determines whether the motion amount is equal to or greater than a predetermined value. Hereinafter, as in the first embodiment, when the motion amount is equal to or less than the predetermined value, AF is performed after the tracking target setting process is performed. When the motion amount is equal to or greater than the predetermined value, AF is performed. The tracking target setting process is executed without performing the above. Then, after the tracking target setting process is completed, the tracking processing unit 58 executes the tracking process, thereby moving the AF area 23 and the target display frame 24 following the movement of the subject set as the tracking target.

  As described above, even if the movement of the subject is detected using the gyro sensor 84 that detects the movement of the camera body 4, the same effect as in the first embodiment can be obtained. In the present embodiment, the movement of the camera body 4 is detected by the gyro sensor 84. However, the present invention is not limited to this, and the movement of the camera body 4 may be detected using another sensor. In this embodiment, a sensor is provided in the motion detection unit 82, but the position of the sensor may be an arbitrary position. Further, a gyro sensor for preventing camera shake may be used for motion detection.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to the flowchart shown in FIG. Note that the configuration of this embodiment is the same as that of the second embodiment, and a description thereof will be omitted.

  When the touch panel 21 detects that a portion corresponding to a predetermined subject has been touched, the CPU 34 of the digital camera 80 switches the setting of the AF function from the normal AF mode to the automatic tracking AF mode in response to the detection. When the automatic tracking AF mode is set, the CPU 34 first moves the AF area 23 fixed at the center of the shooting range to a position corresponding to the detection result of the touch panel 21. Thereafter, the CPU 34 instructs the motion detection unit 82 to execute the motion detection process using the sensor.

  The motion detection unit 82 refers to the output of the gyro sensor 84 in response to an instruction from the CPU 34 to execute the motion detection process. Based on the output, a movement amount indicating the magnitude of the movement of the subject is generated, and the movement amount is input to the CPU 34.

  When the motion amount is input from the motion detection unit 82, the CPU 34 determines whether the motion amount is equal to or greater than a predetermined value. When determining that the amount of movement is equal to or greater than the predetermined value, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting process. On the other hand, when determining that the amount of motion is equal to or less than the predetermined value, the CPU 34 instructs the motion detection unit 82 to execute motion detection processing using image processing.

  When the CPU 34 instructs the motion detection unit 82 to execute the motion detection process, the motion detection unit 82 reads the image data after YC conversion from the SDRAM 45. Then, based on the frame image 22 indicated by the image data, by performing image processing such as feature point tracking, area matching, and a difference in luminance value between frames, the amount of motion of the subject is detected from the frame image 22. The amount of movement is input to the CPU 34.

  When the amount of motion is input from the motion detector 82, the CPU 34 determines again whether or not the amount of motion is a predetermined value or more. When determining that the amount of movement is equal to or greater than the predetermined value, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting process. On the other hand, when the CPU 34 determines that the amount of movement is equal to or less than the predetermined value, the CPU 34 performs the contrast AF based on the AF evaluation value of the AF detection circuit 55 to thereby set the photographing lens 10 on the subject set as the tracking target. Focus. Thereafter, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting process.

  Hereinafter, as in the above embodiments, the tracking target setting processing unit 57 executes the tracking target setting processing in accordance with an instruction from the CPU 34, and after the tracking target setting processing is completed, the tracking processing unit 58 executes the tracking processing. By doing so, the AF area 23 and the target display frame 24 are moved following the movement of the subject set as the tracking target.

  As described above, in this embodiment, when it is determined that the motion amount is equal to or less than the predetermined value in both the motion detection process using the sensor and the motion detection process using the image processing, the tracking is performed after the AF is performed. When the target setting process is executed, and it is determined that one of the motion detection process using the sensor and the motion detection process using the image processing is greater than a predetermined value, the tracking target setting is performed without performing AF. The process was executed.

  As described above, if the motion detection process using the sensor and the motion detection process using the image processing are performed, the motion of the subject can be detected with higher accuracy. In the present embodiment, the motion detection process using the sensor is performed first. On the contrary, the motion detection process using the image process may be performed first. However, between the motion detection process using a sensor and the motion detection process using an image process, the motion detection process using a sensor is relatively faster. Therefore, as shown in the present embodiment, it is possible to detect a subject having a large movement more quickly by performing the motion detection process using the sensor first. That is, it is preferable to perform each motion detection process first with a fast processing speed.

  Further, in this embodiment, when it is determined that the motion amount is greater than or equal to a predetermined value in either the motion detection process using the sensor or the motion detection process using the image process, the tracking target setting is performed without performing AF. In this embodiment, when the motion amount is determined to be greater than or equal to a predetermined value in both the motion detection process using the sensor and the motion detection process using the image process, the AF is performed. The tracking target setting process may be executed without performing the above.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to the flowchart shown in FIG. Note that the configuration of this embodiment is the same as that of the second embodiment, and a description thereof will be omitted.

  When the touch panel 21 detects that a portion corresponding to a predetermined subject has been touched, the CPU 34 of the digital camera 80 switches the setting of the AF function from the normal AF mode to the automatic tracking AF mode in response to the detection. When the automatic tracking AF mode is set, the CPU 34 first moves the AF area 23 fixed at the center of the shooting range to a position corresponding to the detection result of the touch panel 21. Thereafter, the CPU 34 causes the AF detection circuit 55 to calculate the AF evaluation value at the current position of the focus lens 28, and acquires the AF evaluation value.

  When acquiring the AF evaluation value, the CPU 34 determines whether or not the AF evaluation value is equal to or greater than a predetermined value. When the CPU 34 determines that the AF evaluation value is equal to or less than the predetermined value, the CPU 34 performs the contrast AF based on the AF evaluation value of the AF detection circuit 55 to align the photographing lens 10 with the subject set as the tracking target. To burn. Thereafter, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting process.

  On the other hand, when determining that the AF evaluation value is equal to or greater than the predetermined value, the CPU 34 instructs the motion detection unit 82 to execute the motion detection process. The motion detection unit 82 executes a motion detection process in response to an instruction from the CPU 34 to detect a motion amount indicating the magnitude of the motion of the subject, and inputs the motion amount to the CPU 34. At this time, the motion detection process by the motion detection unit 82 may use a sensor or may use image processing.

  When the motion amount is input from the motion detection unit 82, the CPU 34 determines whether the motion amount is equal to or greater than a predetermined value. Hereinafter, as in the above embodiments, when the amount of motion is less than or equal to a predetermined value, AF is performed and then the tracking target setting process is performed. When the amount of motion is greater than or equal to the predetermined value, AF is performed. Without executing the tracking target setting process. Then, after the tracking target setting process is completed, the tracking processing unit 58 executes the tracking process, thereby moving the AF area 23 and the target display frame 24 following the movement of the subject set as the tracking target.

  Thus, in the present embodiment, before executing the motion detection process, the AF evaluation value at the current position of the focus lens 28 is acquired, and if the AF evaluation value is equal to or less than a predetermined value, AF is performed. The tracking target setting process is now performed. In this way, a subject that is not in focus at all is set as a tracking target, and it is possible to more appropriately prevent tracking processing from being continued or shooting being performed in an out-of-focus state. it can. In addition, since the determination is performed based on the AF evaluation value of only one point at the current position of the focus lens 28, the processing does not take much time.

  If the AF evaluation value at the current position of the focus lens 28 is equal to or greater than a predetermined value, there is a high possibility that the subject to be tracked is in focus. Therefore, as shown in the flowchart of FIG. 16, when the AF evaluation value is less than or equal to a predetermined value, the tracking target setting process is performed after AF, and when the AF evaluation value is greater than or equal to the predetermined value, Alternatively, the tracking target setting process may be performed immediately without performing the motion detection process.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described. As shown in FIG. 17, the digital camera 100 of this embodiment is provided with a face detection unit 102 and a scene variation check processing unit 104 in addition to the units described in the above embodiments.

  The face detection unit 102 performs face detection processing for detecting a face image from the image data after YC conversion under the control of the CPU 34. For example, when the face detection function ON is set in the ON / OFF setting item of the face detection function on the menu screen displayed on the liquid crystal display 18 when the menu button 20 is pressed, the CPU 34 causes the face detection unit 102 to Instructs execution of face detection processing. When face detection processing is executed in accordance with an instruction from CPU 34, face detection unit 102 reads image data after YC conversion from SDRAM 45. Then, by using a known pattern matching technique, a face image is extracted from the frame image 22 indicated by the image data, and the position information of the face image is input to the CPU 34 as a detection result. When the position information is input from the face detection unit 102, the CPU 34 generates a face detection frame that encloses a portion corresponding to the face image based on the position information, and displays the frame by overlaying it on the through image. Inform the user of the face.

  The scene change check processing unit 104 performs a scene change check process for determining whether or not there has been a change in the shooting scene in response to an instruction from the CPU 34. The scene variation check processing unit 104 is provided with a reference information storage memory 106. The scene fluctuation check processing unit 104 stores reference information as various types of information related to the shooting scene at the time when an operation that seems to be in focus or close to focus is performed. It is stored in the memory 106.

  For example, the scene fluctuation check processing unit 104 continuously performs focusing during live view display when a photographing preparation process is performed in response to a half-press of the release button 14 when a main photographing is performed. When the AF is operating, it is determined that an operation that seems to be in focus or close to focus is performed, and the reference information storage memory 106 stores the reference information.

  The scene variation check processing unit 104 also includes, for example, the position of the zoom lens 26, the presence / absence of face detection processing by the face detection unit 102, the photometric value calculated by the AE / AWB detection circuit 54, the position of the focus lens 28, and the position thereof. And the like are stored in the reference information storage memory 106 as information relating to the shooting scene. Further, if face detection processing has been performed, the number of face images detected by the face detection processing and the detected face images themselves are stored in the reference information storage memory 106 as information related to the shooting scene. . Note that the operation that the photographing lens 10 seems to be in focus or close to focus and information related to the shooting scene are not limited to the above.

  In response to an instruction from the CPU 34 to execute the scene variation check process, the scene variation check processing unit 104 acquires various information related to the shooting scene in response to the instruction. When the scene variation check processing unit 104 acquires each piece of information, the scene change check processing unit 104 compares each piece of information with reference information stored in the reference information storage memory 106. The scene variation check processing unit 104 determines that there is no variation in the shooting scene when all the corresponding information matches, and there is a case where any one of the corresponding information does not match. Then, it is determined that there has been a change in the shooting scene. The scene variation check processing unit 104 performs the scene variation check process as described above, and then inputs a determination result on whether or not there is a variation in the shooting scene to the CPU 34.

  Next, the operation of the present embodiment having the above configuration will be described with reference to the flowcharts shown in FIGS. When the touch panel 21 detects that the part corresponding to the predetermined subject has been touched, the CPU 34 of the digital camera 100 switches the setting of the AF function from the normal AF mode to the automatic tracking AF mode in response to the detection. When the automatic tracking AF mode is set, the CPU 34 first moves the AF area 23 fixed at the center of the shooting range to a position corresponding to the detection result of the touch panel 21. Thereafter, the CPU 34 instructs the scene variation check processing unit 104 to execute the scene variation check process.

  In response to an instruction from the CPU 34 to execute the scene variation check process, the scene variation check processing unit 104 acquires various types of information related to the shooting scene in response to the instruction. When the scene variation check processing unit 104 acquires each piece of information, it first determines whether or not there has been a variation in the position of the zoom lens 26. The scene variation check processing unit 104 compares the acquired position of the zoom lens 26 with the position of the zoom lens 26 stored as reference information in the reference information storage memory 106, and the difference between these values is equal to or less than a predetermined value. In some cases, it is determined that there is no change in the position of the zoom lens 26, and when it is equal to or greater than a predetermined value, it is determined that there is a change in the position of the zoom lens 26.

  When the scene variation check processing unit 104 determines that the position of the zoom lens 26 has changed, the scene variation check processing unit 104 inputs information indicating that the shooting scene has changed to the CPU 34 and ends the scene variation check process. On the other hand, when the scene variation check processing unit 104 determines that there is no variation in the position of the zoom lens 26, the scene variation check processing unit 104 subsequently determines whether or not there is a variation in the result of the face detection processing by the face detection unit 102.

  When the scene variation check processing unit 104 starts to determine the result of the face detection process, the result of the face detection process currently performed by the face detection unit 102 and the face detection process stored as reference information in the reference information storage memory 106 And confirming whether or not face detection processing is being performed. In addition, when the face detection process is performed, the scene variation check processing unit 104 checks whether or not the number of detected face images matches, and when the number of face images also matches, Furthermore, pattern matching of each detected face image is performed to check whether or not the contents of the corresponding face images match. Then, the scene variation check processing unit 104 determines that there is no variation in the result of the face detection processing when the presence / absence of the face detection processing, the number of face images, and the contents of the face images all match. If any one of them does not match, it is determined that the result of the face detection process has changed.

  When the scene variation check processing unit 104 determines that there is a variation in the result of the face detection process, the scene variation check processing unit 104 inputs information indicating that there is a variation in the shooting scene to the CPU 34 and ends the scene variation check process. On the other hand, when the scene variation check processing unit 104 determines that there is no variation in the result of the face detection process, it subsequently determines whether or not the photometric value calculated by the AE / AWB detection circuit 54 has varied.

  When the scene variation check processing unit 104 starts determination of the photometric value, the photometric value acquired from the AE / AWB detection circuit 54 is compared with the photometric value stored as the reference information in the reference information storage memory 106. When the difference between the photometric values is equal to or less than a predetermined value, it is determined that there is no change in the photometric value, and when it is equal to or greater than the predetermined value, it is determined that the photometric value has changed.

  When the scene variation check processing unit 104 determines that the photometric value has changed, the scene variation check processing unit 104 inputs information indicating that the shooting scene has changed to the CPU 34 and ends the scene variation check process. On the other hand, when the scene variation check processing unit 104 determines that there is no variation in the photometric value, it subsequently determines whether or not there has been a variation in the position of the focus lens 28.

  When the scene variation check processing unit 104 starts determining the position of the focus lens 28, the scene variation check processing unit 104 compares the acquired position of the focus lens 28 with the position of the focus lens 28 stored as reference information in the reference information storage memory 106. When the difference between these values is less than or equal to a predetermined value, it is determined that there is no change in the position of the focus lens 28, and when it is greater than or equal to the predetermined value, it is determined that the position of the focus lens 28 has changed.

  When the scene fluctuation check processing unit 104 determines that the position of the focus lens 28 has changed, the scene fluctuation check processing unit 104 inputs information indicating that the shooting scene has changed to the CPU 34 and ends the scene fluctuation check process. On the other hand, when the scene variation check processing unit 104 determines that there is no variation in the position of the focus lens 28, it subsequently determines whether or not there has been a variation in the AF evaluation value at the position of the focus lens 28.

  When the scene variation check processing unit 104 starts the determination of the AF evaluation value, the AF evaluation value acquired from the AF detection circuit 55 is compared with the AF evaluation value stored as the reference information in the reference information storage memory 106. When the difference between these values is equal to or less than a predetermined value, it is determined that the AF evaluation value does not vary, and when the difference is equal to or greater than the predetermined value, it is determined that the AF evaluation value varies.

  When the scene variation check processing unit 104 determines that the AF evaluation value has changed, the scene variation check processing unit 104 inputs information indicating that the shooting scene has changed to the CPU 34 and ends the scene variation check process. On the other hand, if the scene variation check processing unit 104 determines that there is no variation in the AF evaluation value, the scene variation check processing unit 104 inputs information indicating that there is no variation in the shooting scene to the CPU 34 and ends the scene variation check process.

  When information indicating that there has been a change in the photographic scene is input from the scene change check processing unit 104, the CPU 34 performs the AF of the contrast method based on the AF evaluation value of the AF detection circuit 55, and thereby the tracking target. The photographing lens 10 is focused on the subject set as. Thereafter, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting process.

  On the other hand, when information indicating that there is no change in the shooting scene is input from the scene change check processing unit 104, the CPU 34 instructs the motion detection unit 56 to execute the motion detection process. The motion detection unit 56 performs a motion detection process in response to an instruction from the CPU 34 to detect a motion amount indicating the magnitude of the motion of the subject, and inputs the motion amount to the CPU 34. At this time, the motion detection processing by the motion detection unit 56 may use a sensor or may use image processing.

  When the motion amount is input from the motion detection unit 56, the CPU 34 determines whether the motion amount is equal to or greater than a predetermined value. Hereinafter, as in the above embodiments, when the amount of motion is less than or equal to a predetermined value, AF is performed and then the tracking target setting process is performed. When the amount of motion is greater than or equal to the predetermined value, AF is performed. Without executing the tracking target setting process. Then, after the tracking target setting process is completed, the tracking processing unit 58 executes the tracking process, thereby moving the AF area 23 and the target display frame 24 following the movement of the subject set as the tracking target.

  As described above, in the present embodiment, it is determined whether or not the shooting scene has changed before the motion detection process is executed. If the shooting scene has changed, AF is performed and the tracking target setting process is performed. To do. If the shooting scene has changed from a state where the photographing lens 10 is in focus or in an operation that seems to be in focus, there is a high possibility that the subject to be tracked is not in focus. . Therefore, as described above, it is determined whether or not the shooting scene has changed, and if AF is performed immediately when there is a change, the time-consuming motion detection process can be saved, and more appropriate and The tracking target setting process can be performed quickly.

  Also, if the shooting scene has not changed from the state in which the shooting lens 10 is in focus or close to being in focus, that is, automatically while viewing the same shooting scene as the previous operation. When the tracking AF mode is set, there is a high possibility that the subject to be tracked is in focus. Therefore, as shown in the flowchart of FIG. 20, when there is a change in the shooting scene, AF is performed and then the tracking target setting process is performed. When there is no change in the shooting scene, the AF and the motion detection process are performed. The tracking target setting process may be performed immediately without performing it.

[Sixth Embodiment]
Next, a sixth embodiment of the present invention will be described. As shown in FIG. 21, the digital camera 110 of this embodiment is provided with a setting storage unit 112 in addition to the units described in the above embodiments. The setting storage unit 112 is a non-volatile storage medium such as a flash memory, for example. The setting storage unit 112 stores setting information when the user sets whether to perform AF before the tracking target setting process.

  As shown in FIG. 22, whether or not AF is performed before the tracking target setting process is determined by pressing the menu button 20 to display a menu screen for AF operation setting before automatic tracking displayed on the liquid crystal display 18 (see FIG. 22). AF operation setting means) 114.

  The menu screen 114 includes an ON radio box 115 for setting the AF operation ON mode in which AF is always performed before the tracking target setting process, and AF is not performed before the tracking target setting process. An OFF radio box 116 for setting the AF operation OFF mode, an automatic radio box 117 for setting the AF operation automatic mode for automatically determining whether or not to perform AF before the tracking target setting process, Is provided.

  When the touch panel 21 detects that a portion corresponding to each of the radio boxes 115 to 117 has been touched, the CPU 34 displays a check mark 118 at a position corresponding to the touch operation. This notifies the user that the mode corresponding to the touch operation has been set. Further, the CPU 34 displays a check mark 118 and causes the setting storage unit 112 to store mode setting information corresponding to the operation.

  As described above, the setting of whether or not to perform AF before the tracking target setting process is performed by displaying the menu screen 114 on the liquid crystal display 18 and then touching the portion corresponding to each radio box 115 to 117 in a desired mode. It is set by operating. The setting method of each mode is not limited to the menu screen 114, and may be performed by, for example, a dedicated slide switch.

  Next, the operation of the present embodiment having the above configuration will be described with reference to the flowchart shown in FIG. When the touch panel 21 detects that a portion corresponding to a predetermined subject has been touched, the CPU 34 of the digital camera 110 switches the AF function setting from the normal AF mode to the automatic tracking AF mode in response to the detection. When the automatic tracking AF mode is set, the CPU 34 first moves the AF area 23 fixed at the center of the shooting range to a position corresponding to the detection result of the touch panel 21. Thereafter, the CPU 34 refers to the setting information stored in the setting storage unit 112 to confirm the pre-auto-tracking AF operation mode set by the user.

  When confirming that the AF operation OFF mode is set, the CPU 34 instructs the tracking target setting processing unit 57 to perform the tracking target setting process, and immediately performs the tracking target setting process without performing AF. On the other hand, when confirming that the AF operation ON mode is set, the CPU 34 performs contrast-based AF based on the AF evaluation value of the AF detection circuit 55 to thereby apply the photographing lens to the subject set as the tracking target. 10 is in focus. Thereafter, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting process.

  Further, when confirming that the AF operation automatic mode is set, the CPU 34 instructs the motion detection unit 56 to execute the motion detection process. The motion detection unit 56 performs a motion detection process in response to an instruction from the CPU 34 to detect a motion amount indicating the magnitude of the motion of the subject, and inputs the motion amount to the CPU 34. At this time, the motion detection processing by the motion detection unit 56 may use a sensor or may use image processing.

  When the motion amount is input from the motion detection unit 56, the CPU 34 determines whether the motion amount is equal to or greater than a predetermined value. Hereinafter, as in the above embodiments, when the amount of motion is less than or equal to a predetermined value, AF is performed and then the tracking target setting process is performed. When the amount of motion is greater than or equal to the predetermined value, AF is performed. Without executing the tracking target setting process. Then, after the tracking target setting process is completed, the tracking processing unit 58 executes the tracking process, thereby moving the AF area 23 and the target display frame 24 following the movement of the subject set as the tracking target.

  As described above, in the present embodiment, the mode of the AF operation before automatic tracking set by the user is confirmed by referring to the setting information stored in the setting storage unit 112, and processing corresponding to the mode is performed. Therefore, it is possible to reflect the user's intention as to whether or not AF is performed before the tracking target setting process.

  In this embodiment, when it is confirmed that the AF operation automatic mode is set, a motion detection process is executed, and it is determined whether or not to perform AF depending on whether or not the amount of motion is a predetermined value or more. However, the present invention is not limited to this. For example, an AF evaluation value at the current position of the focus lens 28 may be acquired, and whether or not to perform AF may be determined based on whether or not the AF evaluation value is equal to or greater than a predetermined value. Alternatively, the scene change check process may be executed to determine whether or not to perform AF depending on whether or not the shooting scene has changed.

  In the present embodiment, the AF operation ON mode, the AF operation OFF mode, and the AF operation automatic mode are provided as the settings for the AF operation before automatic tracking. When the AF operation automatic mode is set, the above processes are performed. Although not limited to this, the AF operation before automatic tracking is set only to the AF operation ON mode and the AF operation OFF mode, and the AF operation ON mode is set as shown in the flowchart of FIG. When the AF operation is performed, the tracking target setting process is performed. When the AF operation OFF mode is set, the tracking target setting process may be performed immediately without performing the AF or the motion detection process. Good.

[Seventh Embodiment]
Next, a seventh embodiment of the present invention will be described with reference to the flowchart shown in FIG. Note that the configuration of the present embodiment is the same as that of the sixth embodiment, and a description thereof will be omitted.

  When the touch panel 21 detects that a portion corresponding to a predetermined subject has been touched, the CPU 34 of the digital camera 110 switches the AF function setting from the normal AF mode to the automatic tracking AF mode in response to the detection. When the automatic tracking AF mode is set, the CPU 34 first moves the AF area 23 fixed at the center of the shooting range to a position corresponding to the detection result of the touch panel 21. Thereafter, the CPU 34 refers to the setting information stored in the setting storage unit 112 to confirm the pre-auto-tracking AF operation mode set by the user.

  When confirming that the AF operation ON mode is set, the CPU 34 performs the tracking target setting process after performing AF, as in the sixth embodiment. Also, when it is confirmed that the AF operation automatic mode is set, as in the sixth embodiment, the motion detection process and the determination as to whether or not the motion amount is equal to or greater than a predetermined value are performed. Is equal to or smaller than a predetermined value, the tracking target setting process is executed after the AF is performed, and when the amount of motion is equal to or larger than the predetermined value, the tracking target setting process is performed without performing the AF.

  On the other hand, when confirming that the AF operation OFF mode is set, the CPU 34 causes the AF detection circuit 55 to calculate the AF evaluation value at the current position of the focus lens 28, and acquires the AF evaluation value. When acquiring the AF evaluation value, the CPU 34 determines whether or not the AF evaluation value is equal to or greater than a predetermined value.

  When determining that the AF evaluation value is equal to or greater than the predetermined value, the CPU 34 executes the tracking target setting process without performing AF as set by the user. On the other hand, when the CPU 34 determines that the AF evaluation value is equal to or less than the predetermined value, the icon 120 for warning that the subject selected as the tracking target is not in focus is displayed on the liquid crystal display 18 as shown in FIG. To warn the user. At this time, the CPU 34 displays a dialog box 122 for setting the AF operation mode before automatic tracking to the AF operation OFF mode or the AF operation ON mode together with the icon 120 on the liquid crystal display 18, and the mode is set to the AF operation OFF. The user selects whether to keep the mode or to change to the AF operation ON mode.

  When the part corresponding to the AF operation OFF mode in the dialog box 122 is touched, the CPU 34 executes the tracking target setting process without performing AF. On the other hand, when the part corresponding to the AF operation ON mode of the dialog box 122 is touched, the CPU 34 performs the tracking target setting process after performing AF. At this time, the setting information stored in the setting storage unit 112 may be rewritten from the AF operation OFF mode to the AF operation ON mode according to the setting in the dialog box 122, or may be left in the AF operation OFF mode. May be.

  Then, after completing the tracking target setting process, the CPU 34 causes the tracking processing unit 58 to perform the tracking process, thereby moving the AF area 23 and the target display frame 24 following the movement of the subject set as the tracking target. .

  Thus, in the present embodiment, when the AF operation OFF mode is set, it is determined whether or not the AF evaluation value at the current position of the focus lens 28 is equal to or greater than a predetermined value. That is, a warning is issued when the subject selected as the tracking target by the user is not in focus. In this way, even if you forget to change the setting while reflecting the user's intention, the subject that is not in focus at all is set as the tracking target, and the tracking process cannot be continued or is in focus It is possible to appropriately prevent the shooting from being performed in the absence of the image. In the present embodiment, the user is warned by displaying the icon 120 on the liquid crystal display 18, but the present invention is not limited to this. For example, the warning may be performed by sound such as a warning sound.

[Eighth Embodiment]
Next, an eighth embodiment of the present invention will be described. As shown in FIG. 27, the digital camera 130 of the present embodiment includes a face detection unit 102, a scene variation check processing unit 104, which are the same as those in the fifth embodiment, and a setting storage unit, which is the same as in the sixth embodiment. 112 is provided.

  Next, the operation of the present embodiment having the above configuration will be described with reference to the flowchart shown in FIG. When the touch panel 21 detects that a portion corresponding to a predetermined subject has been touched, the CPU 34 of the digital camera 130 switches the AF function setting from the normal AF mode to the automatic tracking AF mode in response to the detection. When the automatic tracking AF mode is set, the CPU 34 first moves the AF area 23 fixed at the center of the shooting range to a position corresponding to the detection result of the touch panel 21. Thereafter, the CPU 34 refers to the setting information stored in the setting storage unit 112 to confirm the pre-auto-tracking AF operation mode set by the user.

  When confirming that the AF operation OFF mode is set, the CPU 34 instructs the tracking target setting processing unit 57 to execute the tracking target setting processing, and immediately after performing AF, as in the sixth embodiment. Perform tracking target setting processing. Also, when it is confirmed that the AF operation automatic mode is set, as in the sixth embodiment, the motion detection process and the determination as to whether or not the motion amount is equal to or greater than a predetermined value are performed. Is equal to or smaller than a predetermined value, the tracking target setting process is executed after the AF is performed, and when the amount of motion is equal to or larger than the predetermined value, the tracking target setting process is performed without performing the AF.

  On the other hand, when confirming that the AF operation ON mode is set, the CPU 34 instructs the scene variation check processing unit 104 to execute the scene variation check process.

  When information indicating that there has been a change in the shooting scene is input from the scene change check processing unit 104, the CPU 34 determines that there is a high possibility that the subject to be tracked is not in focus, and as set by the user. The tracking target setting process is executed after AF is performed.

  On the other hand, when information indicating that there is no change in the shooting scene is input from the scene change check processing unit 104, the CPU 34 determines that there is a high possibility that the subject to be tracked is in focus, as shown in FIG. As shown in FIG. 4, the icon 132 indicating that the high-speed lock for executing the tracking target setting process without performing AF is possible is displayed on the liquid crystal display 18 to indicate to the user that the high-speed lock is possible. Inform. At this time, the CPU 34 displays a dialog box 122 for setting the AF operation mode before automatic tracking to the AF operation OFF mode or the AF operation ON mode together with the icon 132 on the liquid crystal display 18, and the mode is set to the AF operation ON. The user selects whether to keep the mode or to change to the AF operation OFF mode.

  When the part corresponding to the AF operation OFF mode in the dialog box 122 is touched, the CPU 34 executes the tracking target setting process without performing AF. On the other hand, when the part corresponding to the AF operation ON mode of the dialog box 122 is touched, the CPU 34 performs the tracking target setting process after performing AF.

  Then, after completing the tracking target setting process, the CPU 34 causes the tracking processing unit 58 to perform the tracking process, thereby moving the AF area 23 and the target display frame 24 following the movement of the subject set as the tracking target. .

  As described above, in this embodiment, when the AF operation ON mode is set, the scene variation check process is performed, and if there is no variation in the shooting scene, the user is notified that AF can be omitted. I did it. In this way, it is possible to prevent the AF from being performed unnecessarily when the user forgets to change the setting, and to perform the tracking target setting process more appropriately and quickly while reflecting the user's intention. In the present embodiment, the user is notified by displaying the icon 132 on the liquid crystal display 18, but the present invention is not limited to this, and the notification may be performed by voice, for example.

  In each of the embodiments described above, a subject to be tracked is selected by a touch operation on the touch panel 21, but the method for selecting a tracked target is not limited to this. For example, a face image extracted by performing face detection may be set as a tracking target. In each of the above embodiments, contrast-type AF is performed. However, the AF method is not limited to this, and other methods such as a phase difference method and an active method may be used. In each of the above embodiments, the CCD 36 is shown as an image sensor, but the image sensor is not limited to this, and may be, for example, a CMOS image sensor. In each of the above embodiments, an example in which the present invention is applied to a digital camera has been described. However, the present invention is not limited to this, and may be applied to other imaging apparatuses.

2 Digital camera (imaging device)
4 Camera body (main body)
10 photographic lens 28 focus lens 34 CPU (setting control means)
36 CCD (imaging device)
55 AF detection circuit (AF evaluation value calculation means)
56 Motion detection unit (motion detection means)
57 Tracking target setting processing unit (tracking target setting processing means)
84 Gyro sensor (sensor)
104 Scene variation check processing section (scene variation check processing means)
106 Reference information storage memory (reference information storage means)
114 Menu screen (AF action setting means)

Claims (13)

A photographic lens capable of adjusting the focus by moving the focus lens in the optical axis direction, and an image sensor that images a subject image formed by the photographic lens, and time series by driving the image sensor An image pickup apparatus having a function of acquiring a plurality of continuous image data, performing an autofocus for automatically focusing the photographing lens, and performing a tracking process for automatically tracking a predetermined subject ,
Tracking target setting processing means for extracting a predetermined area from the image data and setting the area as a tracking target of the tracking process;
Movement detection means for detecting movement of the subject;
When the tracking target setting processing unit sets the tracking target, the movement detection unit detects the movement of the subject. When the movement is small, the tracking target setting processing unit performs the autofocus and then performs the tracking target setting processing unit. An image pickup apparatus comprising: a setting control unit that executes setting of a tracking target and causes the tracking target setting processing unit to execute the setting of the tracking target without performing auto focus when the movement is large .   The imaging apparatus according to claim 1, wherein the motion detection unit detects a motion of a subject based on the image data. A main body provided with the photographing lens on the front surface;
A sensor for detecting the movement of the main body,
The imaging apparatus according to claim 1, wherein the movement detection unit detects a movement of a subject based on a detection result of the sensor.   The setting control means automatically detects when the movement is small in both the detection of the movement of the subject based on each image data and the detection of the movement of the subject based on the detection result of the sensor. After performing the focus, the tracking target setting processing unit executes the setting of the tracking target, and the setting control unit detects the movement of the subject based on the image data and the detection result of the sensor. 4. The tracking target setting processing unit is configured to cause the tracking target setting processing unit to execute the setting of the tracking target without performing auto focus when it is detected that the movement is large by either of the detected movements of the subject. The imaging device described. An AF evaluation value calculating means for calculating an AF evaluation value based on the image data;
The setting control unit causes the AF evaluation value calculation unit to calculate an AF evaluation value at the current position of the focus lens when the tracking target setting processing unit sets the tracking target, and the AF evaluation value is If the target value is equal to or smaller than a predetermined value, the tracking target setting processing unit is caused to execute the setting of the tracking target after performing autofocus. The imaging apparatus according to claim 1, further comprising: a control mode that causes the tracking target to be set.   The setting control means sets the tracking target in the tracking target setting processing means without performing auto focus when the AF evaluation value at the current position of the focus lens is a predetermined value or more and the movement of the subject is large. When the AF evaluation value is equal to or less than a predetermined value and when the movement of the subject is small, the tracking target setting processing unit is configured to execute the setting of the tracking target after performing autofocus. The imaging apparatus according to claim 5. Reference information storage means for storing various information related to the shooting scene at that time as reference information when an operation that seems to be in focus or close to focus is performed.
Scene fluctuation check processing means for determining whether or not there has been a change in the shooting scene, based on the reference information stored in the reference information storage means,
The setting control unit causes the scene variation check processing unit to execute a determination when the tracking target setting processing unit sets the tracking target, and when it is determined that there is no variation in the shooting scene, When the tracking target setting processing unit executes the setting of the tracking target without performing the process, and it is determined that there is a change in the shooting scene, auto tracking is performed and the tracking target setting processing unit performs the tracking target setting processing. The imaging apparatus according to claim 1, further comprising a control mode for executing the setting.   The setting control means causes the tracking target setting processing means to execute the setting of the tracking target without performing auto focus when there is no change in the shooting scene and the movement of the subject is large, and there is a change in the shooting scene. The imaging apparatus according to claim 7, wherein, when the movement of the subject is small, the tracking target setting processing unit is configured to execute the setting of the tracking target after performing autofocus.   The reference information storage means stores, as the reference information, any of a zoom lens position of the photographing lens, a result of face detection processing, a photometric value, a position of the focus lens, and an AF evaluation value. Item 9. The imaging device according to Item 7 or 8. AF operation setting means for setting whether to perform autofocus before the tracking target setting processing means sets the tracking target;
The setting control unit confirms the setting by the AF operation setting unit when the tracking target setting processing unit sets the tracking target, and performs auto focus when it is set to perform auto focus. When the tracking target setting processing unit executes the setting of the tracking target and the auto tracking is set not to be performed, the tracking target setting processing unit is set to the tracking target setting processing unit without performing auto focus. The imaging apparatus according to claim 1, wherein the imaging apparatus has a control mode to be executed. The setting of the AF operation setting means includes a mode for automatically determining whether or not to perform autofocus,
When the setting control unit is set to automatically determine autofocus, the detection result of the motion detection unit, the AF evaluation value at the current position of the focus lens, the determination of the scene variation check processing unit The imaging apparatus according to claim 10, wherein whether or not to perform autofocus is determined based on any of the results.   The setting control unit causes the AF evaluation value calculation unit to calculate an AF evaluation value at the current position of the focus lens when the AF operation setting unit is set not to perform autofocus, and the AF evaluation value is calculated. The imaging apparatus according to claim 10 or 11, wherein when the value is equal to or less than a predetermined value, a warning indicating that the focus is not achieved is given.   The setting control unit causes the scene variation check processing unit to determine whether or not the shooting scene has changed when the AF operation setting unit is set to perform autofocus, and if there is no variation in the shooting scene. The imaging apparatus according to any one of claims 10 to 12, wherein when the determination is made, notification indicating that autofocus is omissible is performed.

Images