JP2017034344A - Imaging apparatus and control method thereof - Google Patents

Abstract

An imaging apparatus capable of smoothly and accurately confirming an in-focus state and a control method therefor are provided.
A first image signal acquired by a first pixel group of the plurality of pixels and a second image acquired by a second pixel group of the plurality of pixels. An image pickup means for outputting an image signal, a first control for performing processing based on the second image signal and displaying a first image corresponding to the first image signal on the display screen, and the first image signal And a control means capable of performing a second control for displaying a second image obtained by combining the second image signal and the second image signal on the display screen.
[Selection] Figure 7

Description

  The present invention relates to an imaging apparatus and a control method thereof.

In recent digital cameras and digital video cameras, only the output signals of some of the pixels provided in the image sensor are read, or the output signals of a plurality of pixels are added and read together. Things have been done. These techniques are often used for moving image shooting and live view display. By adopting these methods, the time required for reading can be shortened, and the frame rate can be improved and power consumption can be suppressed.
However, when such a method is used, the resolution is reduced, so it is not easy to accurately check whether the subject is in focus, that is, whether it is in focus or not on the live view display screen. Absent.

  The following techniques have been proposed as techniques for easily confirming whether or not the in-focus state is achieved. Patent Document 1 discloses a technique for displaying a captured image on the screen of an electronic viewfinder and displaying an enlarged portion of an image corresponding to the focus area when performing manual focus while looking at the electronic viewfinder. Yes. Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for cutting out a predetermined partial image from the entire frame and enlarging and displaying the cut out partial image on the entire screen of the liquid crystal monitor when an enlargement switch is instructed.

JP 2001-251540 A Japanese Patent Laid-Open No. 11-298791

  However, with these proposed techniques, it may not be possible to smoothly and accurately confirm whether the focus state is achieved.

  An object of the present invention is to provide an imaging apparatus capable of smoothly and accurately confirming a focused state and a control method therefor.

  According to an aspect of the present invention, a plurality of pixels are provided, an optical image is captured, a first image signal acquired by a first pixel group of the plurality of pixels, and the plurality of pixels Imaging means for outputting a second image signal acquired by the second pixel group, processing based on the second image signal, and displaying a first image corresponding to the first image signal A first control to be displayed on the display unit, and a second control to display on the display unit a second image obtained by combining the first image signal and the second image signal. An image pickup apparatus having a control means is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device which can confirm a focus state smoothly and correctly, and its control method can be provided.

1 is a block diagram illustrating a configuration of an imaging apparatus according to a first embodiment of the present invention. It is a perspective view which shows the structure of the image pick-up element in the imaging device by 1st Embodiment of this invention. It is a figure which shows the circuit structure of the image pick-up element in the imaging device by 1st Embodiment of this invention. It is a figure which shows the example of the selection line at the time of the reading in the imaging device by 1st Embodiment of this invention. It is a time chart which shows operation | movement of the imaging device by 1st Embodiment of this invention. It is the schematic which shows the example of a 1st image signal, a 2nd image signal, and a display image. 3 is a flowchart illustrating an operation of the imaging apparatus according to the first embodiment of the present invention. It is a time chart which shows operation | movement of the imaging device by 2nd Embodiment of this invention. It is the schematic which shows the example of a 1st image signal, a 2nd image signal, and a display image. It is a flowchart which shows operation | movement of the imaging device by 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
An imaging apparatus according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram illustrating the configuration of the imaging apparatus according to the present embodiment.

  The imaging apparatus according to the present embodiment (hereinafter also simply referred to as “camera”) is, for example, an electronic still camera or video camera with an autofocus (AF) function.

  The imaging apparatus 100 according to the present embodiment includes an optical barrel 101, an imaging element 102, a drive unit 103, a signal processing unit 104, a compression / decompression unit 105, a control unit 106, a light emitting unit 107, and an operation unit 108. And an image display unit 109 and an image recording unit 110.

  The optical barrel 101 includes a photographic lens unit (hereinafter also simply referred to as “photographic lens”) 1010 and an optical mechanism unit 1011. The taking lens 1010 collects light from a subject (not shown) on the image sensor 102. That is, the photographing lens 1010 forms an optical image on the image sensor 102.

  Although not shown, the optical mechanism unit 1011 includes an AF mechanism, a zoom drive mechanism, a mechanical shutter mechanism, a diaphragm mechanism, and the like. The optical mechanism unit 1011 is driven by a drive unit (drive circuit) 103 under the control of the control unit 106.

  The image sensor 102 includes a pixel unit 201 (described later) and an A / D converter (not shown). The image sensor 102 is, for example, an XY readout type CMOS image sensor. The imaging element 102 is driven by a driving unit 103 that operates under the control of the control unit 106, performs an imaging operation such as exposure, signal readout, and reset, and outputs an imaging signal (hereinafter also referred to as “image signal”).

  The signal processing unit 104 performs predetermined signal processing such as white balance adjustment processing, color correction processing, and AE (Auto Exposure) processing on the image signal output from the image sensor 102 under the control of the control unit 106. , Output image data. Further, the signal processing unit 104 includes an AF evaluation value calculation unit 1041, an attention area determination unit 1042, and an image composition unit 1043.

  The AF evaluation value calculation unit 1041 obtains an AF evaluation value according to contrast information obtained from the image signal. The AF evaluation value obtained by the AF evaluation value calculation unit 1041 is output to the control unit 106.

  The attention area determination unit 1042 determines the attention area from the captured images acquired by the image sensor 102. Information of the attention area determined by the attention area determination unit 1042 and image information of the attention area are output to the control unit 106. The attention area is an object that the user is paying attention to or an area to be focused by AF.

  The image synthesizing unit 1043 generates a high-resolution image by synthesizing a plurality of image signals, more specifically, by synthesizing a first image signal and a second image signal described later. It is. Note that the angle of view (range) corresponding to the first image signal and the angle of view (range) corresponding to the second image signal may be the same or different. Even if the angle of view corresponding to the first image signal and the angle of view corresponding to the second image signal are different from each other, if there is a common portion, the first image signal and the second image for the common portion A high-resolution image can be partially obtained by combining the image signal.

  The compression / decompression unit 105 operates under the control of the control unit 106. The compression / decompression unit 105 generates encoded image data by performing compression encoding processing on the image data output from the signal processing unit 104. In the compression encoding process, for example, a predetermined still image data format such as a JPEG method is used. JPEG is an abbreviation for Joint Photographic Coding Experts Group. The compression / decompression unit 105 obtains decoded image data by performing an expansion decoding process on the encoded image data transmitted from the control unit 106.

  Note that the compression / decompression unit 105 can also perform compression encoding processing and decompression decoding processing on moving image data. In compression encoding processing and decompression decoding processing for moving image data, for example, a moving picture experts group (MPEG) method or the like is used.

  The control unit 106 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. When the CPU executes a program stored in the ROM, the entire camera 100 is centrally controlled by the control unit 106.

  When it is determined in the AE process performed by the signal processing unit 104 that the exposure value of the subject is low, the control unit 106 controls the light emitting unit 107 to emit light and illuminate the subject. Do. As the light emitting unit 107, for example, a strobe device using a xenon tube, an LED light emitting device, or the like is used.

  The operation unit 108 is, for example, various operation keys such as a shutter release button, a lever, a dial, a touch panel, and the like, and gives an operation signal according to a user input operation to the control unit 106.

  The image display unit 109 includes, for example, a display device (not shown) such as an LCD (Liquid Crystal Display) and an interface circuit (not shown) for the display device. The image display unit 109 displays an image corresponding to the image data sent from the control unit 106 on the display screen of the display device.

  As the image recording unit 110, for example, a recording medium such as a portable semiconductor memory, an optical disk, a HDD (Hard Disk Drive), or a magnetic tape is used. The image recording unit 110 records the encoded image data subjected to the compression encoding process by the compression / decompression unit 105 as an image file. The image recording unit 110 reads the image file designated by the control unit 106 from the recording medium, and outputs the image file to the control unit 106. The control unit 106 obtains decoded image data by causing the compression / decompression unit 105 to perform decompression / decoding processing of the encoded image data read from the image recording unit 110.

Next, the basic operation of the imaging apparatus according to the present embodiment will be described.
For example, when capturing a still image, the image sensor 102 operates as follows before capturing a still image. That is, the image sensor 102 sequentially performs CDS processing and AGC processing on an image signal output from the pixel unit 201 described later, and the image signal subjected to these processing is converted into a digital image using an A / D converter. Convert to signal. The digital image signal thus obtained is sent to the signal processing unit 104.

The AF evaluation value calculation unit 1041 obtains an AF evaluation value, more specifically, a contrast AF evaluation value (contrast control information) based on contrast information obtained from a second image signal described later. The AF evaluation value calculation unit 1041 outputs the AF evaluation value to the control unit 106.
The attention area determination unit 1042 sets an area designated by the user via the operation unit 108 as the attention area, and outputs information about the attention area, that is, attention area information, to the control unit 106.

  Here, the case where the attention area is set by the operation of the operation unit 108 by the user has been described as an example, but the present invention is not limited to this. The attention area may be automatically determined based on the captured image. For example, a person's face or the like may be detected from the photographed image, and an area where the person's face or the like is located may be set as the attention area.

  Based on the AF evaluation value and the attention area information, the control unit 106 determines a control amount for the optical mechanism section 1011 necessary to focus on the subject located in the attention area. The control unit 106 controls the drive unit 103 so that the optical mechanism unit 1011 is controlled with the determined control amount. The AF operation (autofocus control, autofocus process) performed in this way is repeated every frame until the subject is focused.

  The signal processing unit 104 generates a camera-through image signal by performing, for example, image quality correction processing on the digital image signal output from the image sensor 102. The signal processing unit 104 transmits the generated camera through image signal to the image display unit 109 via the control unit 106. The image display unit 109 displays a camera through image (live view image) corresponding to the camera through image signal. The user can adjust the angle of view (framing) while viewing the camera-through image displayed on the image display unit 109.

  When the shutter release button of the operation unit 108 is pressed while the camera through image is displayed on the image display unit 109, the control unit 106 performs the following processing. That is, the control unit 106 controls the imaging device 102 via the driving unit 103 to transmit an imaging signal (digital image signal) for one frame from the imaging device 102 to the signal processing unit 104. The signal processing unit 104 performs, for example, image quality correction processing on the digital image signal for one frame transmitted from the image sensor 102, and transmits the digital image signal (image data) after the image quality correction processing to the compression / decompression unit 105. .

  The compression / decompression unit 105 obtains encoded image data by performing compression encoding processing on the image data. The encoded image data obtained by the compression / decompression unit 105 is transmitted to the image recording unit 110 via the control unit 106. In this way, the image file of the captured still image is recorded in the image recording unit 110.

  When reproducing the image file recorded in the image recording unit 110, the control unit 106 performs the following processing. That is, the control unit 106 reads out the image file selected according to the operation input from the operation unit 108 from the image recording unit 110. Then, the control unit 106 transmits the image file read from the image recording unit 110 to the compression / decompression unit 105. The compression / decompression unit 105 obtains decoded image data by performing an expansion decoding process on the image file. The control unit 106 transmits the decoded image data obtained by the compression / decompression unit 105 to the image display unit 109. The image display unit 109 displays a still image corresponding to the decoded image data.

  On the other hand, when recording moving image data, the control unit 106 performs the following processing. That is, the control unit 106 controls the image sensor 102 via the drive unit 103 to sequentially input digital image signals sequentially output from the image sensor 102 to the signal processing unit 104. The signal processing unit 104 generates image data, that is, moving image data, by sequentially performing predetermined image processing on sequentially input digital image signals. The moving image data generated by the signal processing unit 104 is input to the compression / decompression unit 105. The compression / decompression unit 105 obtains encoded moving image data by performing compression encoding processing on the moving image data. The encoded moving image data obtained by the compression / decompression unit 105 is sequentially transferred to the image recording unit 110 via the control unit 106 and is recorded in the image recording unit 110 as a moving image file.

  When playing back a moving image file recorded in the image recording unit 110, the control unit 106 performs the following processing. That is, the control unit 106 reads out the moving image file selected according to the operation input from the operation unit 108 from the image recording unit 110. The control unit 106 transmits the moving image file read from the image recording unit 110 to the compression / decompression unit 105. The compression / decompression unit 105 obtains decoded moving image data by performing an expansion decoding process on the moving image file. The control unit 106 transmits the decoded moving image data obtained by the compression / decompression unit 105 to the image display unit 109. The image display unit 109 displays a moving image corresponding to the decoded moving image data.

FIG. 2 is a perspective view showing the structure of the image sensor 102 in the imaging apparatus according to the present embodiment.
As shown in FIG. 2, the image sensor 102 includes a first chip 20 and a second chip 21, and a stacked image in which the first chip 20 is stacked on the second chip 21. It is a sensor. The first chip 20 has a plurality of pixel portions (pixels) 201 arranged in a matrix, and the first chip 20 is disposed on the light incident side with respect to the second chip 21. . That is, the first chip 20 is positioned on the light receiving side of the optical image with respect to the second chip 21. In the second chip 21, a pixel driving circuit (peripheral circuit) including column scanning circuits 213a and 213b, which will be described later, and a row scanning circuit 212 is formed.

  If the first chip 20 in which the pixel portion 201 is formed and the second chip 21 in which the peripheral circuit is formed are separated, the manufacturing process of the pixel portion 201 and the manufacturing process of the peripheral circuit can be separated. . For this reason, if the first chip 20 in which the pixel portion 201 is formed and the second chip 21 in which the peripheral circuit is formed are separately provided, it is possible to realize thinning and high density of wiring in the peripheral circuit. The imaging element 102 can be increased in speed, reduced in size, enhanced in functionality, and the like.

FIG. 3 is a diagram illustrating a circuit configuration of the imaging element 102 in the imaging apparatus according to the present embodiment. FIG. 3B shows a circuit configuration of the pixel unit 201.
As shown in FIG. 3A, in the first chip 20, the pixel portions 201 are arranged in a two-dimensional matrix. The pixel portion 201 is connected to the transfer signal line 203, the reset signal line 204, and the row selection signal line 205 in the horizontal direction (row direction), and connected to the column signal line 202a or 202b in the vertical direction (column direction). Each is connected. Note that the pixel portion 201 to which the column signal lines 202a and 202b are connected differs depending on the readout row.

  As shown in FIG. 3B, the pixel unit 201 includes a photodiode PD that is a photoelectric conversion element, a transfer transistor M1, a reset transistor M2, an amplification transistor M3, a selection transistor M4, and a floating diffusion FD. Have. As the transistors M1 to M4, for example, n-channel MOSFETs (MOS Field-Effect Transistors) are used.

  A transfer signal line 203 is connected to the gate of the transfer transistor M1. A reset signal line 204 is connected to the gate of the reset transistor M2. A row selection signal line 205 is connected to the gate of the selection transistor M4. These signal lines 203 to 205 extend in the horizontal direction, and the pixel portions 201 located in the same row are driven simultaneously. As a result, the operation of a line sequential operation type rolling shutter or an all row simultaneous operation type global shutter can be realized. Further, the column signal line 202a or 202b is connected to the source of the selection transistor M4.

  The photodiode PD generates charges by photoelectric conversion. The anode side of the photodiode PD is grounded, and the cathode side of the photodiode PD is connected to the source of the transfer transistor M1. When the transfer transistor M1 is turned on, the charge of the photodiode PD is transferred to the floating diffusion FD. Since there is a parasitic capacitance in the floating diffusion FD, charges transferred from the photodiode PD are accumulated in the floating diffusion FD.

  The power supply voltage Vdd is applied to the drain of the amplification transistor M3, and the gate of the amplification transistor M3 is connected to the floating diffusion FD. The amplification transistor M3 converts the charge accumulated in the floating diffusion FD into a voltage signal. The selection transistor M4 is for selecting the pixel portion 201 from which a signal is read, and the drain of the selection transistor M4 is connected to the source of the amplification transistor M3. The source of the selection transistor M4 is connected to the column signal line 202a or 202b.

  When the selection transistor M4 is turned on, a voltage signal corresponding to the charge accumulated in the floating diffusion FD is output to the column signal line 202a or 202b. The power supply voltage Vdd is applied to the drain of the reset transistor M2, and the source of the reset transistor M2 is connected to the floating diffusion FD. When the reset transistor M2 is turned on, the potential of the floating diffusion FD is reset to the power supply voltage Vdd.

  The second chip 21 is provided with a column ADC block 211, and the column ADC block 211 is connected to the column signal line 202a or 202b. Further, the second chip 21 is provided with a row scanning circuit 212, column scanning circuits 213a and 213b, a timing control circuit 214, and horizontal signal lines (output means) 215a and 215b.

  The timing control circuit 214 controls the operation timing of the row scanning circuit 212, the column scanning circuits 213a and 213b, and the column ADC block 211 under the control of the control unit 106. The row scanning circuit 212 scans each row, and the column scanning circuits 213a and 213b scan each column.

  The horizontal signal lines 215a and 215b transfer the output signal (image signal) output from the column ADC block 211 to the signal processing unit 104 in accordance with the timing controlled by the column scanning circuits 213a and 213b, respectively.

  As will be described later, the image signal transferred to the horizontal signal line 215a is output to the signal processing unit 104 as an image signal for live view display, that is, a first image signal. On the other hand, the image signal transferred to the horizontal signal line 215b is output to the signal processing unit 104 as an AF image signal, that is, a second image signal. The second image signal is used for AF in the AF operation, that is, used to calculate the AF evaluation value. However, when the high-resolution image ((A + B) described later) is generated, the first image signal is used. This is a target to be combined with the image signal.

FIG. 4 is a diagram illustrating an example of a selected row at the time of reading in the imaging apparatus according to the present embodiment.
In FIG. 4, the pixel portions 201 of 8 rows × 6 columns among the plurality of pixel portions 201 arranged in a two-dimensional matrix are extracted and shown. These pixel portions 201 have a Bayer array. In the present embodiment, the selected row and the second image signal are acquired when the first image signal is acquired so that the acquisition of the first image signal and the acquisition of the second image signal can be performed simultaneously. Each selected line is set. The first image signal is output to the column signal line 202a. On the other hand, the second image signal is output to the column signal line 202b.

  Rows with row numbers 1 and 2 are, for example, rows in which a pixel group (second pixel group) for acquiring the second image signal is arranged. Rows with row numbers 3 to 8 are rows in which, for example, a pixel group (first pixel group) for acquiring the first image signal is arranged.

  Since the second image signal is used for AF during the AF operation, it is important to increase the frame rate. For this reason, the second image signal is set to have a relatively high thinning rate. On the other hand, since the second image signal is used for live view display, image quality is important. For this reason, the thinning rate of the second image signal is set to be relatively low.

  In acquiring the first image signal, the first pixel group is read out at the first frame rate. On the other hand, in acquiring the second image signal, the second pixel group is read out at a second frame rate that is faster than the first frame rate.

  As described above, in the present embodiment, a row read when acquiring the first image signal and a row read out for acquiring the second image signal are set separately. Therefore, according to the present embodiment, the first image signal and the second image signal having different charge accumulation times, different data sizes, and different frame rates can be acquired simultaneously.

  Here, the second pixel group for acquiring the second image signal is located in the row of row numbers 1 and 2, and the first pixel group for acquiring the first image signal is row number. Although the case where it located in the 3-8 line was demonstrated to the example, it is not limited to this. Further, the thinning rate in reading can also be set as appropriate.

  The voltage signal (analog signal) output to the column signal line 202a or 202b is converted from an analog signal to a digital signal (image signal) in the column ADC block 211.

  The column scanning circuit 213a transmits the first image signal output from the column ADC block 211 to the signal processing unit 104 via the horizontal signal line 215a. Further, the column scanning circuit 213b transmits the second image signal output from the column ADC block 211 to the signal processing unit 104 via the horizontal signal line 215b.

  Here, a path for outputting the first image signal via the column signal line 202a and the horizontal signal line 215a is referred to as a first channel (CH1), and the path through the column signal line 202b and the horizontal signal line 215b. A path for outputting the second image signal is referred to as a second channel (CH2).

FIG. 5 is a time chart illustrating the operation of the imaging apparatus according to the present embodiment.
As shown in FIG. 5, the imaging timing is defined by the vertical synchronization signal VD. The frame rate of the first image signal output via the first channel CH1 is fixed, but the frame rate of the second image signal output via the second channel CH2 is variable. . Here, the case where the frame rate of the second image signal in the AF operation is four times the frame rate of the first image signal will be described as an example, but the present invention is not limited to this. The first image signal output via the first channel CH1 is used for live view display as described above. Here, a case where live view display is always performed will be described as an example. In FIG. 5, the first image signal is represented by the symbol A, and the second image signal is represented by the symbol B.

  The length of the period from timing T0 to timing T1 corresponds to one frame of the first image signal A. In the period from timing T0 to timing T1, the first image signal A output via the first channel CH1 is acquired. The operation before the timing T1 is a normal operation. Thus, in the normal time, only the first image signal A is read out. FIG. 6A is a schematic diagram illustrating an example of the first image signal A.

  When the user half-presses the release button of the operation unit 108 at the timing T1, that is, when an instruction to prepare for shooting is given by the user, the following operation is performed. That is, after the timing T1, the acquisition of the first image signal A output via the first channel CH1 is continued, and the AF image signal output via the second channel CH2; That is, the acquisition of the second image signal B is started. FIG. 6B is a schematic diagram illustrating an example of the second image signal B. In the present embodiment, the angle of view corresponding to the first image signal A and the angle of view corresponding to the second image signal B are set to be the same. Even after the timing T1, the live view display using the first image signal A is continued in the same manner as before the timing T1, so that the live view display screen does not change unnaturally.

  In the period from timing T1 to timing T2, the AF operation is performed. The AF image signal output via the second channel CH2, that is, the second image signal B is input to the AF evaluation value calculation unit 1041. The AF evaluation value calculation unit 1041 calculates an AF evaluation value based on the second image signal B. The AF evaluation value calculated by the AF evaluation value calculation unit 1041 is transmitted to the control unit 106. When the AF evaluation value does not indicate that the focus state is in focus, the control unit 106 drives the focus lens via the drive unit 103 and the optical mechanism unit 1101 so that the region of interest is in focus. . Such an AF operation is continuously performed until the AF evaluation value exceeds a predetermined value and indicates that it is in focus.

  When the AF evaluation value indicates the in-focus state at timing T2, the control unit 106 ends the AF operation. After terminating the AF operation, the control unit 106 proceeds to a process for performing live view display for focus confirmation. When the AF evaluation value indicates the in-focus state, the user is informed of the in-focus state by means of an electronic sound or a frame display of the in-focus location, but these operations are omitted here. To do.

  In the live view display for focus confirmation, an image (A + B) obtained by combining the first image signal A and the second image signal B is displayed on the display screen of the image display unit 109. Since the second image signal B is used for synthesis, the frame rate of the second image signal B is set equal to the frame rate of the first image signal A after timing T2.

  The first image signal A and the second image signal B captured after the timing T2 are combined by the image combining unit 1043, thereby obtaining a high-resolution display image (A + B) ((A + B in FIG. 5). )). The high-resolution image (display image) (A + B) obtained in this way is displayed in live view on the display screen of the image display unit 109. FIG. 6C is a schematic diagram illustrating an example of a display image (A + B) obtained by combining the first image signal A and the second image signal B. Since the high-resolution image (A + B) is displayed on the image display unit 109, the user can accurately confirm the in-focus state by observing the high-resolution image (A + B).

  Thus, the control unit 106 displays an image corresponding to the first image signal A on the display screen of the image display unit 109 in the normal live view display. In normal live view display, the second image signal B is not acquired and AF control is not performed. During the AF operation, the control unit 106 performs AF control using the second image signal B, and displays an image corresponding to the first image signal A on the display screen of the image display unit 109. In the focus confirmation performed after the AF operation, the control unit 106 displays an image of a high-resolution image (A + B) obtained by combining the first image signal A and the second image signal B. Displayed on the display screen of the unit 109.

  Thus, in this embodiment, when performing AF control, live view display is performed using the first image signal A while performing the AF operation using the second image signal B. Then, when performing focus confirmation, a high-resolution image (A + B) obtained by combining the first image signal A and the second second image signal B is displayed. Since the high-resolution image (A + B) is displayed, the in-focus confirmation can be performed accurately. In addition, when displaying a high-resolution image (A + B) for in-focus confirmation, the entire display is not switched to the partial display. Further, when displaying a high-resolution image (A + B) for focusing, a large time lag does not occur. As described above, according to the present embodiment, it is possible to provide an imaging apparatus capable of smoothly and accurately confirming the in-focus state.

  In Patent Document 1 described above, since only a part of an image with low resolution is enlarged, it is not always possible to confirm whether or not it is in focus sufficiently accurately. Further, in Patent Document 2, since the image displayed on the screen of the liquid crystal monitor changes from the entire image to the partial image, framing cannot be confirmed.

  FIG. 7 is a flowchart illustrating the operation of the imaging apparatus according to the present embodiment. 7 is executed under the control of the control unit 106.

  When the power source of the camera 100 is set to the on state and the camera 100 is set to the shooting mode by an operation input from the operation unit 108, the control unit 106 performs imaging for live view display, that is, as described above. Acquisition of the first image signal A is started (step S701). In imaging for live view display, as described above with reference to FIG. 4, the image signal from the pixel unit 201 located in the selected row for acquiring the first image signal A, that is, the first image signal. A is read out. Note that the first image signal A is output via the first channel CH1 as described above.

  In step S702, an image for live view display is generated by performing predetermined image processing on the first image signal A. The live view display image generated in this way is displayed on the display screen of the image display unit 109.

  In step S703, the control unit 106 detects whether or not the release button of the operation unit 108 has been pressed halfway. When the release button is pressed halfway, SW1 (not shown) is turned on. If the release button is not half-pressed, that is, if SW1 is not on (NO in step S703), the process returns to step S701, and imaging for live view display, that is, acquisition of the first image signal A is continued. Is done.

  The state where the release button is half-pressed, that is, the state where SW1 is on means that the photographer has instructed the camera to prepare for taking a still image. Therefore, when the release button is half-pressed (YES in step S703), the control unit 106 controls the camera 100 so that a still image can be taken in an optimal state, and the process proceeds to step S704.

  In step S704, the control unit 106 simultaneously performs imaging for live view display, that is, acquisition of the first image signal A and imaging for AF, that is, acquisition of the second image signal B. As described above with reference to FIG. 4, the first image signal A is read from the pixel unit 201 located in the selected row for acquiring the first image signal A, and the second image signal B is Read out from the pixel unit 201 located in the selected row for acquiring the second image signal B.

  In step S705, predetermined image processing is performed on the first image signal A, thereby generating an image for live view display. The live view display image generated in this way is displayed on the display screen of the image display unit 109.

  In step S706, the control unit 106 performs an AF operation. Specifically, the AF evaluation value calculation unit 1041 calculates the AF evaluation value using the second image signal B. The control unit 106 drives the focus lens via the drive unit 103 and the optical mechanism unit 1101 by outputting a control signal corresponding to the AF evaluation value to the drive unit 103. As described above with reference to FIG. 5, the frame rate of the second image signal B can be set faster than the frame rate of the first image signal A. In step S706, the acquisition of the second image signal B is performed a plurality of times during one frame of the first image signal A. Here, detailed description of the repeated acquisition of the second image signal B is omitted.

  In step S707, the control unit 106 confirms whether or not the in-focus state has been achieved. If not in focus (NO in step S707), the process returns to step S704, and the live view display and AF operation are continued. On the other hand, when the in-focus state is reached (YES in step S707), the process proceeds to step S708.

In step S708, the control unit 106 adjusts the frame rate for acquiring the second image signal B. Specifically, the control unit 106 sets the frame rate of the second image signal B to be equal to the frame rate of the first image signal A.
In step S709, the control unit 106 simultaneously acquires the first image signal A and the second image signal B.

  In step S710, the control unit 106 combines the first image signal A and the second image signal B by the image combining unit 1043. Since the pixel unit 201 read when acquiring the first image signal A and the pixel unit 201 read when acquiring the second image signal B are in a complementary relationship, the combined image (A + B) ) Is a high-resolution image that has not been thinned out.

  In step S711, predetermined image processing is performed on the image synthesized in step S710 to generate a live view image for in-focus confirmation. The live view image for focus confirmation generated in this way is displayed on the display screen of the image display unit 109. A high-resolution image (A + B) that has not been thinned out is displayed as a live view image for in-focus confirmation, and the in-focus state can be confirmed accurately.

  In step S712, the control unit 106 determines whether or not the live view display for focusing confirmation is to be terminated. If the live view display for focus confirmation is not finished (NO in step S712), the process returns to step S709 to obtain the first image signal A and the second image signal B and display the live view for focus confirmation. Again. When the live view display for focusing confirmation is to be ended (YES in step S712), the photographing operation is ended.

  As described above, in this embodiment, when displaying an in-focus confirmation image, a high-resolution image obtained by combining the first image signal A and the second second image signal B. (A + B) is displayed. Since the high-resolution image (A + B) is displayed, the in-focus state can be confirmed accurately. In addition, when displaying a high-resolution image (A + B) for in-focus confirmation, the entire display is not switched to the partial display. Further, when displaying a high-resolution image (A + B) for focusing, a large time lag does not occur. As described above, according to the present embodiment, it is possible to provide an imaging apparatus capable of smoothly and accurately confirming the in-focus state.

[Second Embodiment]
An image pickup apparatus and a control method thereof according to the second embodiment will be described with reference to FIGS. The same components as those in the imaging apparatus and the control method thereof according to the first embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  In the imaging apparatus according to the present embodiment, the angle of view corresponding to the first image signal A is different from the angle of view corresponding to the second image signal B.

FIG. 8 is a time chart illustrating the operation of the imaging apparatus according to the present embodiment.
As shown in FIG. 8, the imaging timing is defined by the vertical synchronization signal VD. Also in the present embodiment, as in the first embodiment, the frame rate of the first image signal A is fixed, but the frame rate of the second image signal B is variable. Here, a case where the frame rate of the second image signal B in the AF operation is set to 8 times the frame rate of the first image signal A will be described as an example, but the present invention is not limited to this. Similar to the first embodiment, the first image signal A is used for live view display.

  Before the timing T1, the first image signal A is read out as in the first embodiment. FIG. 9A is a schematic diagram illustrating an example of the first image signal A. FIG.

  At timing T1, when the user half-presses the release button of the operation unit 108, that is, when an instruction to prepare for shooting is given by the user, the following operation is performed. That is, in the present embodiment, as in the first embodiment, after the timing T1, the acquisition of the first image signal A is continued and the acquisition of the second image signal B is started. FIG. 9B is a schematic diagram illustrating an example of the second image signal B. As shown in FIG. 9B, in this embodiment, the angle of view corresponding to the first image signal A is different from the angle of view corresponding to the second image signal B. More specifically, in this embodiment, the angle of view corresponding to the second image signal B is set smaller than the angle of view corresponding to the first image signal A. The angle of view corresponding to the second image signal B, that is, the reading area of the second image signal B is a target subject region (target region) that is a region including a target subject that is a subject to be focused. .

  In the present embodiment, since the angle of view corresponding to the second image signal B is set smaller than the angle of view corresponding to the first image signal A, the data amount of the second image signal B in the present embodiment. Is smaller than the data amount of the second image signal B in the first embodiment. For this reason, in this embodiment, the frame rate at the time of acquiring the 2nd image signal B can be made faster than the case of 1st Embodiment. Even after timing T1, live view display is performed using the first image signal A, as in the first embodiment. Since the live view display similar to that before the timing T1 is performed after the timing T1, the live view display screen does not change unnaturally as in the first embodiment.

  In the period from the timing T1 to the timing T2, the AF operation is performed as in the first embodiment. The second image signal B is input to the AF evaluation value calculation unit 1041. The AF evaluation value calculation unit 1041 calculates an AF evaluation value based on the second image signal B. The AF evaluation value calculated by the AF evaluation value calculation unit 1041 is transmitted to the control unit 106. When the AF evaluation value does not indicate that the focus state is in focus, the control unit 106 drives the focus lens via the drive unit 103 and the optical mechanism unit 1101 so that the region of interest is in focus. . Such an AF operation is continuously performed until the AF evaluation value exceeds a predetermined value and indicates that it is in focus.

  When the AF evaluation value indicates the in-focus state at the timing T2, the control unit 106 ends the AF operation as in the first embodiment. After terminating the AF operation, the control unit 106 proceeds to a process for performing live view display for focus confirmation.

  In live view display for focus confirmation, an image (A + B) obtained by combining the first image signal A and the second image signal B is displayed. For this reason, after the timing T2, the frame rate for acquiring the second image signal B is set to be equal to the frame rate for acquiring the first image signal A.

  The first image signal A and the second image signal B captured after the timing T2 are combined by the image combining unit 1043, whereby a high-resolution image (A + B) is obtained ((A + B) in FIG. 8). . The high-resolution image (A + B) obtained in this way is displayed in live view on the image display unit 109. FIG. 9C is a schematic diagram illustrating an example of a display image (A + B) obtained by combining the first image signal A and the second image signal B. As shown in FIG. 9C, the portion of the angle of view corresponding to the second image signal B, that is, the attention area has a high resolution, and the attention area having the high resolution is enlarged and displayed. . Since the attention area is displayed on the image display unit 109 with high resolution, the user can accurately check the in-focus state by observing the attention area with high resolution.

  Here, the case where the attention area with improved resolution is enlarged and displayed has been described as an example, but the present invention is not limited to this. For example, the attention area with improved resolution may be displayed without being enlarged, or only the attention area with improved resolution may be cut out and displayed on the entire display screen of the image display unit 109.

FIG. 10 is a flowchart illustrating the operation of the imaging apparatus according to the present embodiment. Note that the operation shown in FIG. 10 is executed under the control of the control unit 106.
First, the operations from step S1001 to step S1003 are the same as the operations from step S701 to step 703 of the first embodiment, and thus description thereof is omitted.

If the release button is pressed halfway (YES in step S1003), the process proceeds to step S1004.
In step S <b> 1004, the control unit 106 acquires attention area information by the attention area determination unit 1042.

  In step S <b> 1005, the control unit 106 instructs the drive unit 103 to set a reading area in order to read the AF image signal output from the pixel unit 201 in the attention area, that is, the second image signal B. Do. Note that the second image signal B is output via the second channel CH2 as described above.

  Steps S1006 to S1011 are the same as steps S704 to S709 in the first embodiment, and thus description thereof is omitted.

  In step S1012, the control unit 106 synthesizes the first image signal A and the second image signal B by the image synthesis unit 1043. Since the pixel unit 201 read out when acquiring the first image signal A and the pixel unit 201 read out when acquiring the second image signal B are complementary to each other in the attention area, The portion of the attention area in the image is an image that has not been thinned out.

  In step S1013, predetermined image processing is performed on the image synthesized in step S1012, and a live view image for focus confirmation is generated. At this time, a live view image for focus confirmation is generated so that the attention area with improved resolution is displayed in an enlarged manner. The live view image for focus confirmation generated in this way is displayed on the display screen of the image display unit 109. Since the attention area is displayed with high resolution and the attention area is enlarged, the user can accurately check the in-focus state.

  Since step S1014 is the same as step 712 of the first embodiment, description thereof is omitted.

  As described above, in the present embodiment, when displaying an in-focus confirmation image, the first image signal A and the second image signal B are combined to increase the resolution of the attention area. , Zoom in on the region of interest. In addition, when displaying a high-resolution image (A + B) for in-focus confirmation, the entire display is not switched to the partial display. Further, when displaying a high-resolution image (A + B) for focusing, a large time lag does not occur. Also in the present embodiment, it is possible to provide an imaging apparatus that can check the in-focus state smoothly and accurately.

  In the above-described embodiment, the case where the AF control is performed using the second image signal B has been described as an example. However, the present invention can also be applied to a manual focus operation in which the photographer himself focuses. it can. In this case, the second image signal B is used, for example, for processing for assisting manual focus. Examples of the process for assisting the manual focus include a process for informing the user whether or not the camera is in the focused state by changing the display mode of the focused frame.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment, The various form changed in the range which does not deviate from the summary is also contained in this invention.

(Other examples)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 101 ... Optical barrel 102 ... Image pick-up element 103 ... Drive part 104 ... Signal processing part 106 ... Control part 108 ... Operation part 109 ... Image display part 1010 ... Shooting lens 1011 ... Optical mechanism part 1041 ... AF evaluation value calculation part 1042 ... Attention Area discriminating unit 1043 ... image compositing unit

Claims (10)

A first image signal that includes a plurality of pixels and that is acquired by a first pixel group of the plurality of pixels, and a second image signal that is acquired by a second pixel group of the plurality of pixels Imaging means for outputting
A first control for performing processing based on the second image signal and displaying a first image corresponding to the first image signal on a display screen; the first image signal and the second image signal; And a control unit capable of performing a second control to display a second image obtained by combining the two on the display screen. The imaging apparatus according to claim 1, wherein the processing based on the second image signal is autofocus control. The imaging apparatus according to claim 1, wherein the process based on the second image signal is an assist of manual focus. 4. The imaging apparatus according to claim 1, wherein an angle of view corresponding to the second image signal is smaller than an angle of view corresponding to the first image signal. 5. The imaging apparatus according to claim 4, wherein the angle of view corresponding to the second image signal is an angle of view corresponding to a region including a subject to be focused. The imaging apparatus according to claim 1, wherein a frame rate of the second image signal in the first control is faster than a frame rate of the first image signal. 2. When displaying the second image, the portion where the resolution is improved by combining the first image signal and the second image signal is enlarged and displayed. The imaging device according to any one of 6. A first image signal that includes a plurality of pixels and that is acquired by a first pixel group of the plurality of pixels, and a second image signal that is acquired by a second pixel group of the plurality of pixels A control method of an imaging apparatus including an imaging means for outputting
Performing a process based on the second image signal and displaying a first image corresponding to the first image signal on a display screen;
A method of controlling an imaging apparatus, comprising: displaying a second image obtained by combining the first image signal and the second image signal on the display screen.   A non-transitory computer-readable storage medium storing a program for causing a computer to execute the control method for an imaging apparatus according to claim 8.   A computer-readable recording medium storing a program for causing a computer to execute the control method for an imaging apparatus according to claim 8.

Images