JP2012065112A - Imaging apparatus - Google Patents

Abstract

The detection range of an optical sensor is expanded.
An image pickup apparatus includes an image pickup device that picks up a subject as a main image, and an optical sensor arranged at a position optically conjugate with the image pickup device, and the optical sensor receives an output that receives visible light. And an output that receives infrared light in addition to visible light is selectively output. In the above imaging apparatus, when the infrared cut filter and the optical sensor receive visible light, the infrared cut filter is advanced to the front of the optical sensor, and the optical sensor receives infrared light in addition to visible light. And a filter switching unit for retracting the infrared cut filter from the front surface of the optical sensor.
[Selection] Figure 6

Description

  The present invention relates to an imaging apparatus.

It has been proposed that a tracking device for tracking a subject by causing a photometric sensor and a distance measuring sensor to cooperate with each other is provided in an imaging device (see Patent Document 1).
[Prior art documents]
[Patent Literature]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2008-009053

  However, tracking may be interrupted when the amount of light in the object scene is insufficient, or when the tracking target and the background have a similar color.

  In order to solve the above problems, as one embodiment of the present invention, an imaging device that captures a subject as a main image, and an optical sensor disposed at a position optically conjugate with the imaging device are provided. There is provided an imaging apparatus that selectively outputs an output that receives light and an output that receives infrared light in addition to visible light.

  The above summary of the present invention does not enumerate all necessary features of the present invention. A sub-combination of these feature groups can also be an invention.

1 is a schematic cross-sectional view of a single-lens reflex camera 100. FIG. 6 is a schematic diagram showing the structure of a filter switching unit 610. FIG. 6 is a schematic diagram showing a structure of a filter switching unit 620. FIG. 6 is a schematic diagram for explaining a method for determining the specification of an alternative filter 623. FIG. 2 is a block diagram schematically showing an internal circuit 500. FIG. 5 is a flowchart showing a control procedure of a selection control unit 512. 5 is a flowchart illustrating a control procedure of a tracking control unit 514. 5 is a flowchart illustrating a control procedure of a tracking control unit 514. 5 is a flowchart illustrating a control procedure of a tracking control unit 514. 6 is a schematic diagram showing a structure of a filter switching unit 630. FIG.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a schematic cross-sectional view of a single-lens reflex camera 100. The single-lens reflex camera 100 includes a lens unit 200 and a camera body 300.

  The lens unit 200 includes a fixed cylinder 210, a plurality of lenses 220, 230, and 240, a lens mount 250, and a lens barrel CPU 260. One end of the fixed barrel 210 is coupled to the body mount 360 of the camera body 300 via the lens mount 250.

  The coupling between the lens mount 250 and the body mount 360 can be released by a specific operation. Accordingly, another lens unit 200 having the same standard lens mount 250 can be attached to the camera body 300.

  In the lens unit 200, the lens 220 located far from the camera body 300 is directly supported from the fixed barrel 210. In contrast, the other lenses 230 and 240 move in the direction of the optical axis OA with respect to the fixed cylinder 210. Thereby, the optical system of the lens unit 200 is zoomed or focused.

  For example, the lens 230 is one of zoom lenses that move when the magnification of the lens unit 200 is changed. The lens 240 is one of focusing lenses that move when the focal position of the lens unit 200 is changed.

  The lens barrel CPU 260 controls the operation of the lens unit 200 and also communicates with the camera body 300. Thus, when the lens unit 200 is attached to the camera body 300, the lens unit 200 operates in cooperation with the camera body 300.

  The camera body 300 includes a mirror unit 400 disposed behind the body mount 360 with respect to the lens unit 200. A focusing optical system 380 is disposed below the mirror unit 400. A focusing screen 352 is disposed above the mirror unit 400.

  A pentaprism 354 is disposed above the focusing screen 352, and a finder optical system 356 is disposed behind the pentaprism 354. The rear end of the finder optical system 356 is exposed on the back surface of the camera body 300 to form a finder 350.

  A photometric sensor 390, which is a kind of optical sensor, is disposed behind the pentaprism 354. The position of the photometric sensor 390 is a position optically conjugate with the imaging element 330 with respect to the optical system of the lens unit 200.

  The photometric sensor 390 receives a part of the subject light beam branched by the pentaprism 354 through one of the filters held by the turret 612. The turret 612 holds a plurality of filters and can be switched by the switching motor 614 to switch the filter to be placed in front of the photometric sensor 390. This point will be described later with reference to other drawings.

  The photometric sensor 390 detects the brightness of the subject from a part of the received subject luminous flux, and causes the main body CPU 322 to calculate the exposure condition. Also, a part of the received light flux of the subject can be measured for each of the three primary colors to calculate the color distribution of the subject.

  Behind the mirror unit 400, a focal plane shutter 370, a low-pass filter 332, and an image sensor 330 are sequentially arranged. A main board 320 and a display unit 340 are sequentially arranged behind the image sensor 330. A main body CPU 322, an image processing unit 324, and the like are mounted on the main board 320. The display unit 340 is formed of, for example, a liquid crystal display panel and is exposed on the back surface of the camera body 300.

  The mirror unit 400 includes a main mirror 420 and a sub mirror 460. The main mirror 420 is supported by the main mirror holding frame 410. One end of the main mirror holding frame 410 is pivotally supported by the main mirror rotating shaft 430.

  When the front end of the main mirror holding frame 410 is lowered due to the rotation, the main mirror holding frame 410 comes into contact with the positioning pin 440 near the front end and stops. As a result, the main mirror 420 stops at a position that accurately forms 45 degrees with respect to the subject light beam incident from the lens unit 200. Thus, the main mirror 420 stops at an oblique position that is obliquely arranged on the subject light beam incident from the lens unit 200.

  Further, when the front end of the main mirror holding frame 410 rises, the main mirror holding frame 410 comes into contact with the stopper 480 near the front end and stops. As a result, the main mirror 420 stops at the retracted position retracted from the optical path of the subject light flux.

  The sub mirror 460 is held by the sub mirror holding frame 450. One end of the sub mirror holding frame 450 is pivotally supported from the main mirror holding frame 410 by a sub mirror rotating shaft 470. Therefore, the sub mirror 460 rotates with respect to the main mirror holding frame 410. When the main mirror holding frame 410 rotates, the sub mirror 460 and the sub mirror holding frame 450 also move together with the main mirror holding frame 410.

  At the oblique position, the main mirror 420 reflects the subject light beam incident through the lens unit 200 and guides it to the focusing screen 352. The focusing screen 352 is arranged at a position where the subject images are connected when the optical system of the lens unit 200 is focused, and visualizes the subject image.

  The subject image formed on the focusing screen 352 is observed from the viewfinder 350 through the pentaprism 354 and the viewfinder optical system 356. Here, when the luminous flux of the subject image passes through the pentaprism 354, the subject image on the focusing screen 352 can be observed as an erect image from the viewfinder 350.

  Further, the main mirror 420 has a half mirror region that transmits a part of the incident subject light flux. The sub mirror 460 reflects a part of the subject light beam incident from the half mirror region toward the focusing optical system 380. The focusing optical system 380 guides a part of the incident subject light beam to a distance measuring sensor 382 which is a kind of optical sensor.

  The distance measuring sensor 382 is disposed at a position optically conjugate with the image sensor 330 with respect to the optical system of the lens unit 200. Thereby, the camera body 300 can determine the position of the lens 230 when the lens unit 200 is focused. The distance measuring sensor 382 receives light through one of the filters held by the turret 622. The turret 622 can switch a filter to be advanced in front of the distance measuring sensor 382 by holding a plurality of filters and rotating by the switching motor 624. This point will be described later with reference to other drawings.

  When the single-lens reflex camera 100 as described above is in a standby state, the main mirror 420 is in an oblique position. Therefore, when the release button is half-pressed, the distance measuring sensor 382 and the photometric sensor 390 are enabled, and the subject image can be captured under appropriate shooting conditions.

  Next, when the release button is fully pressed, the main mirror 420 and the sub mirror 460 move to the retracted position, and the focal plane shutter 370 opens. Therefore, the subject luminous flux incident from the optical system of the lens unit 200 passes through the low-pass filter 332 and enters the image sensor 330. Thereby, a subject image is formed on the light receiving surface of the image sensor 330.

  The imaging element 330 is formed by a photoelectric conversion element such as a CCD sensor (Charge Coupled Device) or a CMOS sensor (Complementary Metal Oxide Semiconductor), and converts the subject image into an electrical signal. As described above, the image sensor 330 is used when a subject image is captured as a main image.

  FIG. 2 is a diagram schematically illustrating the structure of the filter switching unit 610. In the figure, the same reference numerals are assigned to the same elements as in FIG.

  The circular turret 612 holds the infrared cut filter 611 and the alternative filter 613 at positions symmetrical with respect to the center. A driven gear 616 that rotates integrally with the turret 612 is disposed at the center of the turret 612 so as to be coaxial with the turret 612 itself.

  The driven gear 616 meshes with the drive gear 618 mounted on the rotation shaft of the switching motor 614, and the turret 612 rotates when the switching motor 614 rotates. Thereby, the infrared cut filter 611 and the alternative filter 613 held by the turret 612 selectively advance to the front surface of the photometric sensor 390.

  The infrared cut filter 611 blocks infrared rays and transmits visible light having a shorter wavelength. On the other hand, the alternative filter 613 transmits visible light and infrared light without blocking them. Thus, the photometric sensor 390 selectively selects an output when receiving visible light and an output when receiving infrared light in addition to visible light, according to the type of filter that has advanced to the front surface. Output.

  The alternative filter 613 has a refractive index in which infrared light is focused at the same position as the focal position of visible light that has passed through the infrared cut filter. As a result, the photometric sensor 390 produces an equivalent output whether it passes through the infrared cut filter 611 or the alternative filter 613.

  FIG. 3 is a diagram schematically illustrating the structure of the filter switching unit 620. In the figure, the same reference numerals are assigned to the same elements as in FIG.

  The circular turret 622 holds the infrared cut filter 621 and the alternative filter 623 at positions symmetrical with respect to the center. A driven gear 626 that rotates integrally with the turret 622 is disposed on the side peripheral surface of the turret 622 so as to be coaxial with the turret 622 itself.

  The driven gear 626 meshes with a drive gear 628 mounted on the rotation shaft of the switching motor 624, and the turret 622 rotates when the switching motor 624 rotates. As a result, the infrared cut filter 621 and the alternative filter 623 held by the turret 622 selectively advance to the front surface of the distance measuring sensor 382.

  The infrared cut filter 621 blocks infrared rays and transmits visible light having a shorter wavelength. On the other hand, the alternative filter 623 transmits both visible light and infrared light without blocking. Accordingly, the distance measuring sensor 382 selectively selects an output when receiving visible light and an output when receiving infrared light in addition to visible light, according to the type of filter that has advanced to the front surface. Output to.

  Note that the alternative filter 623 has a refractive index at which the infrared light is focused at the same position as the focal position of the visible light transmitted through the infrared cut filter 621. As a result, the distance measuring sensor 382 produces an equivalent output whether it passes through the infrared cut filter 621 or the alternative filter 623.

  The refractive index of the material that can be used as the infrared cut filter 621 is about 1.5, whereas the refractive index of the material used as the optical glass is distributed from about 1.2 to 1.6. Therefore, the alternative filter 623 can be manufactured using a material having the same refractive index and thickness. In addition, the characteristic of the alternative filter 623 can be matched to the infrared cut filter 621 by adjusting the thickness of the alternative filter 623.

FIG. 4 is a diagram for explaining a method for determining the specification of the alternative filter 623. As shown in the figure, the relationship between the incident angle θ to the alternative filter 623 placed in the air, the incident angle γ from the alternative filter 623 to the air, the refractive index n of the alternative filter 623, and the thickness t of the alternative filter 623 is shown in FIG. If it is deformed after being described according to the above law, it can be expressed as the following equation 1.

On the other hand, the optical path length deviation δ (= L ₂ −L ₁ ) of the light incident on the alternative filter 623 can be expressed as the following Expression 2.

Here, when Expression 1 is substituted into Expression 2 and the optical path length deviation δ is expressed by the incident angle θ and the refractive index n, it can be expressed as Expression 3 below.

Therefore, in order to make the optical path length shift δ ₁ generated by the infrared cut filter 621 equal to the optical path length shift δ ₂ generated by the alternative filter 623, the infrared cut filter 621 has a thickness t ₁ and a refractive index n ₁ . When the alternative filter 623 has a thickness t ₂ and a refractive index n ₂ , it can be seen that the following expression 4 should be satisfied.

From Equation 4, the optical path length deviation δ ₂ of the alternative filter 623 can be made equal to the optical path length deviation δ ₁ of the infrared cut filter 621 by appropriately selecting the thickness t ₂ or the refractive index n ₂ of the alternative filter 623. I understand. For example, when the refractive index n ₁ and the thickness t _{1 of} the infrared cut filter 621 are determined, the thickness t ₂ is adjusted according to the refractive index n ₂ for the infrared band of the material that can be used as the alternative filter 623. As a result, an alternative filter 623 having the same characteristics as the infrared cut filter 621 is obtained.

  FIG. 5 is a block diagram schematically showing the internal circuit 500 of the single-lens reflex camera 100. The internal circuit 500 is formed by elements connected directly or indirectly to the main body CPU 322. Thus, the main body CPU 322 comprehensively controls the single-lens reflex camera 100 as a whole.

  A program memory 520 and a main memory 530 are connected to the main body CPU 322. Program memory 520 includes at least one of a nonvolatile recording medium and a read-only recording medium, and stores firmware and the like executed by main body CPU 322. The main memory 530 includes a RAM and is used as a work area for the main body CPU 322.

  The main body CPU 322 controls the operation of the entire single-lens reflex camera 100 by the firmware read from the program memory 520. Further, the main body CPU 322 forms the selection control unit 512 with additional firmware read from the program memory 520. Further, the selection control unit 512 includes a tracking control unit 514.

  An imaging unit 540 is connected to the main body CPU 322. The imaging unit 540 includes an imaging device 330, an imaging device driving unit 542, an analog / digital conversion unit 544, and an image processing unit 324. The image sensor 330 is driven at a specific timing by the image sensor drive unit 542, photoelectrically converts the subject image, and outputs an image signal.

  The image signal output from the imaging device 330 is discretized by the analog / digital conversion unit 544 and converted into image data by the image processing unit 324. The image processing unit 324 adjusts image white balance, sharpness, gamma, gradation correction, compression, and the like in the process of generating image data.

  The image data generated by the image processing unit 324 is stored and saved in the secondary recording medium 550. As the secondary recording medium 550, a medium having a non-volatile storage element such as a flash memory card is used. Note that at least a part of the secondary recording medium 550 can be detached from the camera body 300 and replaced.

  A distance measuring sensor 382 and a photometric sensor 390 are connected to the main body CPU 322. The distance measuring sensor 382 detects the position of the focus lens in the lens unit 200 in order to focus the subject image on the image sensor 330. The main body CPU 322 controls the operation of the lens unit 200 with reference to the detected focus position.

  The photometric sensor 390 receives a part of the subject luminous flux incident on the camera body 300 through the lens unit 200 and detects the subject luminance. Accordingly, the main body CPU 322 calculates shooting conditions such as sensitivity of the image sensor 330, shutter speed, aperture opening, presence / absence of auxiliary illumination, and transmits instructions to each unit of the single-lens reflex camera 100.

  Furthermore, an input unit 560 and a display driving unit 570 are connected to the main body CPU 322. The input unit 560 accepts input from the operation unit 562 such as a release button, dial, cross key, and push button arranged mainly on the surface of the camera body 300, and holds input instructions, setting values, and the like. The main body CPU 322 refers to the input unit 560 and obtains a setting value that is a precondition when the shooting condition is calculated.

  The display driving unit 570 generates an image to be displayed on the display unit 340 and displays the image on the display unit 340. The display unit 340 displays the captured image read from the secondary recording medium 550 when the single-lens reflex camera 100 is operating in the playback mode. In addition, when the single-lens reflex camera 100 is operating in the shooting mode, the display unit 340 displays set setting values such as shutter speed, aperture value, image sensor sensitivity, exposure correction, and the like.

  Furthermore, the display unit 340 displays a through image obtained from the image sensor 330 when the single-lens reflex camera 100 operates in the live view mode. In this case, the display unit 340 is used as a finder. Even in the live view mode, the shooting conditions may be displayed together with the through image or by dividing a partial area on the screen.

  Furthermore, the display unit 340 forms a mode selection unit that performs various settings for the single-lens reflex camera 100 in cooperation with the operation unit 562 and the input unit 560. That is, in the mode selection unit, any one of a plurality of options displayed on the display unit 340 is specified by operating the operation unit 562, and the input unit 560 holds a setting value corresponding to the specified option. Thus, the selected mode is set in the single-lens reflex camera 100.

  The switching drive unit 580 instructs the switching drive unit 580 on the type of filter to be advanced in front of the photometric sensor 390 or the distance measuring sensor 382 in the filter switching units 610 and 620. The switching drive unit 580 operates the switching motors 614 and 624 according to the instruction to rotate the turrets 612 and 622. Accordingly, either the infrared cut filters 611 and 621 or the alternative filters 613 and 623 held by the turret 612 selectively advance in front of the photometric sensor 390 and the distance measuring sensor 382.

  The infrared irradiation unit 590 is disposed on the front surface of the camera body 300 and irradiates the infrared light in a band that passes through the alternative filters 613 and 623 toward the object field of the single-lens reflex camera 100. Thereby, the subject is illuminated with infrared rays. A light emitting diode or the like can be used as the infrared light source.

  The tracking control unit 514 captures and tracks the tracking target designated by the user or automatically extracted by software in the object field, and when the release button of the camera body 300 is pressed down, the tracking control unit 514 The operation of focusing the lens unit on the tracking target is controlled. The tracking control unit 514 captures and tracks the tracking target using the photometric sensor 390, the distance measuring sensor 382, and the like.

  The selection control unit 512 monitors the outputs of the photometry sensor 390 and the distance measurement sensor 382 in the control of the tracking control unit 514. When the outputs of the photometric sensor 390 and the distance measuring sensor 382 are smaller than a predetermined threshold, the selection control unit 512 controls the switching drive unit 580 and the infrared irradiation unit 590 to improve the effective sensitivity of the tracking control unit 514. Let

  FIG. 6 is a flowchart showing a control procedure of the selection control unit 512. The selection control unit 512 first checks whether the tracking mode is set for the camera body 300 (step S101). When the tracking mode is not set in the camera body 300 (step S101: NO), the selection control unit 512 ends the control.

  Note that the selection control unit 512 may confirm that the infrared cut filter 611 has advanced before the distance measuring sensor 382 and the photometric sensor 390 prior to the end of control. Thus, the distance measuring sensor 382 and the photometric sensor 390 receive the visible light filtered from the infrared light and detect the exposure condition and the focusing condition with high accuracy when photographing the subject.

  When the tracking mode is set in the camera main body 300 (step S101: YES), the selection control unit 512 has outputs of the photometric sensor 390 and the distance measuring sensor 382 exceeding predetermined thresholds, and the tracking control unit 514. Checks whether the tracking target can be recognized (step S102). When the tracking target is detected (step S102: YES), the control of the camera body 300 is transferred from the selection control unit 512 to the tracking control unit 514 (step S112). The control procedure of the tracking control unit 514 will be described later with reference to other drawings.

  If it is determined in step S102 that the outputs of the photometric sensor 390 and the distance measuring sensor 382 have not reached the predetermined threshold value and the tracking control unit 514 has not been able to detect the tracking target (step S102: NO). The selection control unit 512 checks whether or not the input unit 560 is allowed to remove the infrared cut filter 611 (step S103). If it is not permitted to remove the infrared cut filter 611 (step S103: NO), the selection control unit 512 warns that the tracking target cannot be tracked because there is no response to the inability to recognize the tracking target. Is generated (step S104), and the selection control is terminated.

  When it is determined in step S103 that the infrared cut filter 611 is permitted to be removed (step S103: YES), the selection control unit 512 instructs the switching drive unit 580 to perform the filter switching units 610 and 620. The infrared cut filters 611 and 621 are retracted, and the alternative filters 613 and 623 are advanced in front of the photometry sensor 390 and the distance measurement sensor 382.

  As a result, the distance measuring sensor 382 and the photometric sensor 390 are in a state of receiving both the visible term band and the infrared band. Accordingly, the distance measuring sensor 382 and the photometric sensor 390 each receive infrared light in addition to visible light and generate an output. Thereby, even when the object scene is dark or the color of the subject is close to the background color, the subject to be tracked can be recognized by the distribution of infrared light.

  Next, the selection control unit 512 checks again whether or not the tracking control unit 514 points out the tracking target (step S106). When the tracking control unit 514 recognizes the tracking target (step S106: YES), the control of the camera body 300 is transferred from the selection control unit 512 to the tracking control unit 514 (step S112).

  When it is determined in step S106 that the tracking control unit 514 has not recognized the tracking target (step S106: NO), the selection control unit 512 determines whether or not infrared auxiliary light is permitted in the input unit 560. (Step S107).

  When irradiation with infrared auxiliary light is not permitted (step S106: NO), the selection control unit 512 has no response to the inability to recognize the tracking target. Therefore, the selection control unit 512 generates a warning that the tracking target cannot be tracked (step S108) and ends the selection control.

  When it is determined in step S107 that the irradiation with infrared auxiliary light is permitted (step S107: YES), the selection control unit 512 turns on the infrared irradiation unit 590 (step S109). Thereby, the infrared irradiation unit 590 illuminates the object scene with infrared rays.

  Further, the selection control unit 512 checks again whether or not the tracking control unit 514 recognizes the tracking target (step S110). When the tracking control unit 514 has not yet recognized the tracking target (step S110: NO), the selection control unit 512 has no response to the fact that the tracking target cannot be detected. Therefore, a warning that the tracking target cannot be tracked is generated (step S111), and the selection control is terminated. If the tracking control unit 514 recognizes the tracking target in step S110 (step S111: YES), the control of the camera body 300 is transferred from the selection control unit 512 to the tracking control unit 514.

  As described above, the selection control unit 512 increases the detection sensitivity of the tracking control unit 514 through the step of expanding the detection range by removing the infrared cut filter 611 and the step of illuminating the subject with infrared auxiliary light. Try. As a result, when the tracking control unit 514 recognizes the tracking target, the control of the camera body 300 moves from the selection control unit 512 to the tracking control unit 514 to prepare for shooting while tracking the tracking target.

  FIG. 7 is a flowchart showing the control procedure of the tracking control by the tracking control unit 514. The tracking control unit 514 to which control is passed from the above steps S102, S106, and S110, when the tracking mode is set in the input unit 560 and the user starts operating the single-lens reflex camera 100 in preparation for shooting, for example, Tracking control starts when the release button is pressed halfway.

  The tracking control unit 514 that has started the control first enables the photometric sensor 390, and calculates photometric information including the luminance distribution and color distribution of the object scene from the output of the photometric sensor 390 (S201). Next, the tracking control unit 514 enables the distance measuring sensor 382 and calculates defocus information including the distribution of the defocus amount in the object scene (S202).

  Next, the tracking control unit 514 extracts the luminance distribution, the color distribution, and the defocus amount distribution in the region including the tracking target, generates a template corresponding to the tracking target, and records this (step S203). In addition, the tracking control unit 514 generates a tracking frame that surrounds an area including the tracking target (step S204).

  The tracking control unit 514 updates the template and the tracking frame generated in this way through the update process (step S205). The update process in step S205 is repeated until an instruction to shoot is given to the camera body 300 (step S206: NO), and the tracking frame continues to track the tracking target as described later. That is, when the update process is executed in step S205, the tracking control unit 514 checks the state of the operation unit 562 acquired from the input unit 560, for example, whether or not the release button is fully pressed. Whether or not shooting is instructed is checked (step S206).

  When shooting is instructed to the camera body 300 (step S206: YES), the tracking control unit 514 executes shooting processing (step S207) and ends the tracking control. If the camera body 300 is not instructed to shoot (step S206: NO), the tracking control unit 514 repeats the update process (step S205) and continues tracking the tracking target. Such continuation of tracking control is terminated when the user indicates an intention to interrupt shooting, for example, when the release button that was initially half-pressed is released.

  FIG. 8 is a flowchart showing a control procedure of the tracking control unit 514 in the update process (step S205) of the tracking control (step S112). When the update process (step S205) is started, the tracking control unit 514 enables the photometric sensor 390 again and calculates photometric information from the output of the photometric sensor 390 (step S301). Further, the tracking control unit 514 enables the distance measuring sensor 382 again and calculates defocus information from the output of the distance measuring sensor 382 (step S302).

  Subsequently, the tracking control unit 514 compares the photometric information and defocus information calculated in steps S301 and S302 with the template generated in step S203 shown in FIG. 7, and evaluates the matching with the template based on the magnitude of the difference. (Step S303). As a result, the tracking frame is moved to an area where the difference between the photometric information and the defocus information included in the template is the smallest (S304).

  The tracking control unit 514 that has moved the tracking frame focuses the lens unit 200 in the area surrounded by the tracking frame at the movement destination (step S305). Thereby, the optical system of the single-lens reflex camera 100 is focused on the tracking target.

  Next, the tracking control unit 514 updates the template based on the photometric information and defocus information of the area included in the moved tracking frame (step S306). Thus, the update process by the tracking control unit 514 ends.

  In the above example, the matching with the template is evaluated by combining the photometric information including the luminance distribution and the color distribution with the defocus information. However, matching with the template may be evaluated with reference to photometric information including one of the luminance distribution and the color distribution. Further, matching with a template may be evaluated by defocus information alone.

  FIG. 9 is a flowchart showing a control procedure of the tracking control unit 514 in the imaging process (step S207) of the tracking control (step S112). When the photographing process is started in step S207, the tracking control unit 514 first calculates the outputs of the photometric sensor 390 and the distance measuring sensor 382 to calculate the exposure condition and the focusing condition (step S401).

  Next, an instruction is issued to the switching drive unit 580, and the infrared cut filters 611 and 621 are advanced again in front of the photometric sensor 390 and the distance measuring sensor 382 (step S402). Further, the tracking control unit 514 then exposes the image sensor 330 under the calculated exposure condition and focusing condition to photograph the tracking target (step S403).

  Instead of using the alternative filters 613 and 623, the outputs of the photometric sensor 390 and the distance measuring sensor 382 may be corrected by calculation between step S402 and step S403. That is, the difference between detection results for the visible light band and the infrared band in the photometric sensor 390 and the distance measuring sensor 382 is measured and recorded in advance, and the detection result detected by receiving the infrared band is corrected. May be.

  Next, the tracking control unit 514 checks whether or not the continuous shooting mode is set in the camera body 300 (step S404). When the continuous shooting mode is not set in the camera body 300, that is, when the single shooting mode is set in the camera body 300 (step S404: NO), the tracking control unit 514 ends the shooting process.

  In step 404, when the continuous shooting mode is set in the camera body 300 (step S404: YES), the tracking control unit 514 first executes an update process (step S205). Next, it is checked whether or not there is an instruction to end the shooting from the user (step S405).

  If an instruction to end shooting has not been received (step S405: NO), the tracking control unit 514 returns to step S401 to shoot the subject. When receiving an instruction from the user to end the shooting, such as opening the release button detected from the input unit 560 (step S405: YES), the tracking control unit 514 ends the shooting process.

  A program for executing a series of control procedures as described above may be installed in the camera body 300 in advance, or may be provided through a secondary storage medium, a communication line, etc., and read into the camera body 300 for use. . Further, it may be mounted on a remote controller, a personal computer or the like that controls the operation of the camera body 300 from the outside.

  FIG. 10 is a schematic diagram showing the structure of another filter switching unit 630 that can be used for the photometric sensor of the camera body 300. As illustrated, the filter switching unit 630 includes a plurality of pixels 632 arranged two-dimensionally. Each of the pixels 632 is formed by a photoelectric conversion element such as a photoresistor, a photodiode, or a phototransistor that converts received light into an electrical signal.

  Each pixel 632 includes a filter having a different transmission band, as indicated by alphabetical symbols in the figure. That is, each of the pixels 632 includes a G filter that transmits the green band, a B filter that transmits the blue band, an R filter that transmits the red band, and an IR filter that transmits the infrared band.

  Further, as indicated by a dotted line in the drawing, in the filter switching unit 630, one unit color pixel 634 is formed by combining four pixels 632. Each unit color pixel 634 includes one G filter, one B filter, one R filter, and one IR filter, as shown in an enlarged view in the lower part of the drawing.

  The filter switching unit 630 as described above can be used as an image sensor including color information by reading signals from three pixels 632 having a G filter, a B filter, and an R filter. Further, by reading the output of the pixel 632 having the IR filter together, the visible light band and the infrared band can be detected together. Therefore, in the camera main body 300, the filter can be switched without using a movable part by using it as the photometric sensor 390.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

100 single lens reflex camera, 200 lens unit, 210 fixed tube, 220, 230, 240 lens, 250 lens mount, 260 lens barrel CPU, 300 camera body, 320 main substrate, 322 body CPU, 324 image processing unit, 330 image sensor, 332 low-pass filter, 340 display unit, 350 finder, 352 focusing screen, 354 pentaprism, 356 finder optical system, 360 body mount, 370 focal plane shutter, 380 focusing optical system, 382 distance measuring sensor, 390 photometric sensor, 400 mirror Unit, 410 Main mirror holding frame, 420 Main mirror, 430 Main mirror rotation axis, 440 Positioning pin, 450 Sub mirror holding frame, 460 Sub mirror, 470 Sub mirror Moving shaft, 480 stopper, 500 internal circuit, 512 selection control unit, 514 tracking control unit, 520 program memory, 530 main memory, 540 imaging unit, 542 imaging element driving unit, 544 analog / digital conversion unit, 550 secondary recording medium 560 input unit, 562 operation unit, 570 display drive unit, 580 switching drive unit, 590 infrared irradiation unit, 610, 620, 630 filter switching unit, 611, 621 infrared cut filter, 612, 622 turret, 613, 623 Filter, 614, 624 Switching motor, 616, 626 Driven gear, 618, 628 Drive gear, 632 pixels, 634 unit color pixel

Claims (8)

An image sensor for imaging a subject as a main image;
An optical sensor disposed at a position optically conjugate with the imaging element;
The optical sensor selectively outputs an output that receives visible light and an output that receives infrared light in addition to visible light. An infrared cut filter,
When the optical sensor receives visible light, the infrared cut filter is advanced to the front surface of the optical sensor, and when the optical sensor receives infrared light in addition to visible light, from the front surface of the optical sensor. The imaging apparatus according to claim 1, further comprising a filter switching unit that retracts the infrared cut filter. An alternative filter having a refractive index that transmits infrared light and has a refractive index at which the focal position of infrared light comes to the same position as the focal position of visible light that has passed through the infrared cut filter,
The imaging apparatus according to claim 2, wherein the filter switching unit causes the alternative filter to advance to the front surface of the optical sensor when the optical sensor receives infrared light in addition to visible light.   The imaging apparatus according to claim 1, wherein the optical sensor is a photometric sensor.   A selection control unit that recognizes an object based on the output of the photometric sensor and selects an output that receives infrared light in addition to visible light when the output of the photometric sensor with respect to reception of visible light is smaller than a threshold value. The imaging device according to claim 4, further comprising:   The imaging apparatus according to claim 1, wherein the optical sensor is a distance measuring sensor.   Selection for recognizing a subject based on the output of the distance measuring sensor and selecting an output that receives infrared light in addition to visible light when the output of the distance measuring sensor with respect to reception of visible light is smaller than a threshold value The imaging device according to claim 6, further comprising a control unit.   The imaging apparatus according to claim 1, further comprising an infrared irradiation unit that irradiates infrared light toward the subject.

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