JP2017092605A - Imaging apparatus and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of obtaining an excellent image in which an image element capable of performing a focal detection of a pupil division system is used and a noise is suppressed.SOLUTION: In an image element of which a pixel having a plurality of photo diodes is arranged in a two-dimensional state, the image element is driven and controlled in either one of a first reading mode that reads out a signal 603 of a focus point detection processing and a signal 601 of an output image and a second mode that reads out signals 600, 602 of the output image without reading the signal of the focus detection processing. When the signal of a plurality of pixels in a serial direction of the image element is mixed and read out, the number of pixels mixed and read out is different depending on the first reading mode and the second reading mode. Thus, reduction of the number of pixels in the serial direction of the output image is prevented, and an excellent image in which a noise is suppressed can be obtained.SELECTED DRAWING: Figure 6

Description

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

  There has been disclosed a technique capable of pupil-focusing focus detection in an image sensor used for a digital camera, a digital video camera, or the like. For example, Patent Document 1 discloses a configuration in which one pixel of an imaging element has two photodiodes, and each photodiode receives light that has passed through different pupil regions of the imaging lens by one microlens. . In this configuration, it is possible to detect the focus by the imaging lens by comparing the output signals from the two photodiodes, and obtain the signal of the photographed image by mixing the output signals from the two photodiodes. it can.

JP 2001-124984 A

  When reading a signal from the above-described imaging device capable of pupil division focus detection, when reading a signal for automatic focus detection (autofocus, AF) and when not reading a signal for automatic focus detection It is conceivable to change the signal reading method. For example, when only the normal imaging signal is read without reading the auto focus detection signal, the output signals of a plurality of pixels in the vertical direction (column direction) are used to increase the readout speed of the image signal from the imaging device. Read with mixing. Further, when reading both the auto focus detection signal and the normal imaging signal, it is conceivable to read out the output signals of a plurality of pixels in the column direction without mixing them. However, in this signal readout method, the number of pixels that are mixed and read out in the column direction is reduced, so that noise such as moire may occur in an image with a high spatial frequency.

  An object of the present invention is to provide an imaging apparatus capable of obtaining a good image with suppressed noise using an imaging element capable of pupil division type focus detection.

  An image pickup apparatus according to the present invention includes an image pickup element in which a plurality of pixels each having a plurality of photoelectric conversion elements are arranged two-dimensionally, a processing unit that performs a focus detection process based on a signal from the image pickup element, A first readout mode for reading out the signal for focus detection processing and the signal for output image from the image sensor; and a second mode for reading out the signal for output image without reading out the signal for focus detection processing from the image sensor. Control means for driving and controlling the image sensor in any one of the readout modes, the control means when the mixed output signal of a plurality of pixels in the column direction is read from the image sensor. Control is performed so that the number of pixels read out by mixing output signals is different between the first readout mode and the second readout mode.

  According to the present invention, when focus detection processing is not performed, it is possible to increase the number of pixels in the column direction where the output signals are mixed in reading out the output image signal, and the number of pixels in the column direction where the output signals are mixed is increased. It is possible to obtain a good image in which noise is suppressed and noise is suppressed.

It is a figure which shows the structural example of the imaging device by embodiment of this invention. It is a figure which shows the structural example of the image pick-up element in this embodiment. It is a conceptual diagram with which the light beam which came out of the exit pupil of the imaging lens in this embodiment injects into a unit pixel. It is an equivalent circuit diagram of a pixel in the present embodiment. It is a figure explaining the vertical pixel mixing by the row selection in 1st Embodiment. It is a figure which shows the state according to the presence or absence of the read-out for AF in 1st Embodiment. It is a figure which shows the example of the reading position of the signal for AF in 1st Embodiment. 6 is a timing chart illustrating an example of driving at the time of signal reading in the vertical 3/3 mixing according to the first embodiment. 6 is a timing chart illustrating an example of driving at the time of signal reading in the vertical 2/3 mixing according to the first embodiment. 6 is a timing chart illustrating an example of driving at the time of AF signal reading in the first embodiment. 3 is a flowchart illustrating an operation example of the imaging apparatus according to the first embodiment. It is an equivalent circuit diagram of a pixel capable of FD mixing in the first embodiment. It is a timing chart which shows the example of FD mixing in 1st Embodiment. It is a figure explaining the example which transfers to AF signal read-out without AF signal read-out in 2nd Embodiment. It is a figure explaining the other example which transfers to AF signal read-out without AF signal read in 2nd Embodiment. It is a figure explaining the other example which transfers to AF signal read-out without AF signal read in 2nd Embodiment. 10 is a flowchart illustrating an operation example of the imaging apparatus according to the second embodiment. It is a figure which shows the example of the to-be-photographed object in 3rd Embodiment. 10 is a flowchart illustrating an operation example of the imaging apparatus according to the third embodiment.

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

(First embodiment)
FIG. 1 is a block diagram illustrating a configuration example of an imaging apparatus according to an embodiment of the present invention. Next, each block will be described.

  First, the imaging device 100 will be described. The shutter 12 controls the amount of light entering the image sensor 1400. The image sensor 1400 converts an optical image into an electrical signal. The optical finder 104 confirms the composition of a still image taken by the user by forming incident light that has entered through an optical system such as a lens or an aperture when the mirror 130 is on the optical axis with the mirror 131. Is possible.

  The analog front end circuit 1700 includes an analog / digital converter (A / D converter) that converts an analog signal output from the image sensor 1400 into a digital signal. A timing generator (hereinafter referred to as TG) 1800 supplies a clock signal and a control signal to the image sensor and the A / D converter, respectively.

  The liquid crystal monitor 1200 can display a live view image and a captured still image. A system control circuit (for example, CPU: Central Processing Unit) 50 controls the entire imaging apparatus 100 including image processing.

  The shutter switch 61 has two stages, and the user presses lightly to the first step is called half-press, and pressing the button deeply to the second step is called full press. When the shutter switch 61 is half-pressed, the system control circuit 50 detects the auto focus detection (auto focus, AF: Auto Focus) processing and the setting of the shutter speed and aperture value by the automatic exposure mechanism in the state before photographing. Done. Further, when the shutter switch 61 is fully pressed, the shutter 12 is operated and the photographing operation is performed.

  The start / stop switch 62 for the live view operation performs a live view operation for continuously displaying images obtained by the image sensor 1400 on the liquid crystal monitor 1200 when a start instruction is given by the user. When the shutter switch 61 is pressed halfway during live view display, autofocus processing using the focus detection output signal of the image sensor 1400 is performed.

  In the ISO sensitivity setting switch 63, the system control circuit 50 sets the sensitivity of the imaging apparatus 100 with respect to the amount of light according to a user instruction. In the power switch 64, the system control circuit 50 switches the power of the imaging apparatus 100 on and off according to a user instruction. In addition, the power on and power off settings of various accessory devices such as the lens unit 300, the external strobe, and the recording medium 200 connected to the imaging device 100 can be switched.

  A volatile memory (for example, RAM: Random Access Memory) 70 temporarily records image data. The volatile memory 70 also has a function as a work memory of the system control circuit 50. A nonvolatile memory (for example, ROM: Read Only Memory) 71 stores a program used when the system control circuit 50 operates.

  The image processing unit 72 performs processing such as still image correction / compression. The autofocus calculation unit 73 calculates a position change amount of a lens 310 described later from a focal length detection signal for autofocus processing. The subject analysis unit 74 measures the spatial frequency of the subject.

  The power control unit 80 includes a battery detection circuit, a DC-DC converter, a switch circuit that switches blocks to be energized, and the like. Further, the presence / absence of a battery, the type of battery, the remaining battery level are detected, the DC-DC converter is controlled based on the detection result and the instruction of the system control circuit 50, and the necessary voltage is recorded for a necessary period. Supply to each part including The power supply unit 86 includes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a lithium ion battery, an AC adapter, or the like, and is connected to the power supply control unit 80 via connectors 82 and 84.

  The interface 90 with the recording medium 200 is connected to the recording medium 200 such as a memory card or a hard disk via a connector 92. The recording medium 200 includes a recording unit 201 configured with a semiconductor memory, a magnetic disk, and the like, and an interface 202 with the imaging apparatus 100.

  The lens unit 300 includes a lens 310, a diaphragm 312, and a lens mount 316. The lens mount 316 is connected to the lens mount 106 of the imaging device 100. The lens control unit 320 is electrically connected to the connector 122 on the imaging device 100 side via the connector 322. The lens control unit 320 receives a signal from the imaging apparatus 100 via the connectors 322 and 122. The position on the optical axis of the lens 310 is changed by a signal from the imaging device 100 to control the focus. Similarly, the lens control unit 320 receives a signal from the image processing apparatus 100 and controls the size of the aperture of the diaphragm 312. Reference numeral 120 denotes an interface for communicating with the lens unit 300 using an electrical signal.

  FIG. 2 is a diagram illustrating a configuration example of the image sensor 1400. In the pixel unit 208, a plurality of pixels (unit pixels) 205 are arranged in a matrix (two-dimensional), and the arrangement in the vertical direction (column direction) is referred to as a “column”, and the horizontal direction (row direction). The line is called a “line”. The vertical scanning circuit 204 outputs a signal necessary for row selection for reading a selected row and reading of electric charges to each pixel circuit for each row.

  Each pixel 205 of the pixel unit 208 is connected to a vertical output line (column output line) 410 of a corresponding column. The signal output to the vertical output line 410 is output to the horizontal scanning circuit 203 via the column gain amplifier 206 and the column circuit 207 connected to each vertical output line 410. The horizontal scanning circuit 203 sequentially outputs the signal output for one row in the horizontal direction.

  FIG. 3 is a conceptual diagram in which the light beam emitted from the exit pupil 307 of the photographing lens enters the unit pixel. The unit pixel 205 includes a microlens 304, a color filter 305, a first photodiode 306A, and a second photodiode 306B. That is, each of the plurality of pixels 205 arranged two-dimensionally in the pixel portion 208 includes a plurality of photodiodes (photoelectric conversion elements) 306A and 306B included in one microlens.

  For the pixel having the microlens 304, the optical axis 303 is the center of the light beam emitted from the exit pupil. The light that has passed through the exit pupil enters the unit pixel 205 around the optical axis 303. As shown in FIG. 3, the light beam passing through the pupil region 301 that is a partial region of the exit pupil of the photographing lens is received by the first photodiode 306A through the microlens 304. The light beam passing through the pupil region 302 that is a partial region of the exit pupil of the photographing lens is received by the second photodiode 306B through the microlens 304. As described above, the photodiodes 306A and 306B receive light from different areas of the exit pupil of the photographing lens. Therefore, the phase difference can be detected by comparing the signals of the photodiodes 306A and 306B.

  Here, a signal obtained from the first photodiode 306A is defined as an A image signal, and a signal obtained from the second photodiode 306B is defined as a B image signal. A signal obtained by mixing the A image signal and the B image signal is an A + B image signal, and the A + B image signal can be used for a captured image (output image).

  FIG. 4 shows an equivalent circuit diagram of the pixel (unit pixel) 205. The charge generated and accumulated in the first photodiode 306A is transferred to the floating diffusion portion (hereinafter referred to as FD) 407 by controlling the transfer switch 405A by the transfer control signal 401. Further, the charge generated and accumulated in the second photodiode 306B is transferred to the FD 407 by controlling the transfer switch 405B with the transfer control signal 402. That is, transfer switches 405A and 405B are provided for each photodiode (for each photoelectric conversion element) in the photodiodes 306A and 306B included in the pixel 205.

  The source follower amplifier 408 amplifies a voltage signal based on the electric charge accumulated in the FD 407 and outputs it as a pixel signal. The output of the source follower amplifier 408 is connected to the vertical output line 410 by controlling the row selection switch 409 with the row selection control signal 404. When resetting unnecessary charges accumulated in the FD 407, the reset switch 406 is controlled by a reset control signal 403. Further, when resetting the photodiodes 306A and 306B, the transfer switches 405A and 405B are controlled by the transfer control signals 401 and 402 together with the reset switch 406 to execute the reset.

  The transfer control signals 401 and 402, the reset control signal 403, and the row selection control signal 404 are connected to the vertical scanning circuit 204, and each control signal is supplied to each row. The transfer control signals 401 and 402, the reset control signal 403, and the row selection control signal 404 are output by the system control circuit 50 controlling the vertical scanning circuit 204 via the TG 1800.

  Here, both the A image signal and the B image signal are necessary for the correlation calculation in the focus detection process. In this example, a method of reading A + B image signals for normal imaging (output image) signals, and separately reading A and B image signals for AF (focus detection processing) signals will be described. . The system control circuit 50 controls the autofocus calculation unit 74 to control the focus by controlling the lens control unit 320 based on the result calculated from the A image signal and the B image signal.

  FIG. 5 is a diagram for explaining vertical pixel mixing by row selection in the present embodiment. FIG. 5 shows an operation when the vertical scanning circuit 204 mixes vertical predetermined pixels. In FIG. 5, for convenience of explanation, the pixel (unit pixel) 205 and the row selection switch 409 are illustrated separately, and the pixel 205_i and the row selection switch 409_i (i is a natural number) are respectively the pixels 205 in the i-th row. , A row selection switch 409. In the following, a method in which signals from a plurality of pixels are substantially mixed and averaged by turning on a plurality of row selection switches 409 that connect the pixels 205 to a vertical output line (column output line) 410 and turning them on (conductive state). Will be described as an example.

  FIG. 5A shows an operation example when mixing signals of three pixels in the vertical direction. As shown in FIG. 5A, the row selection switches 409_1, 409_3, and 409_5 are selected, and the signals of the pixels 205 in the first, third, and fifth rows are output to the vertical output line (column output line) 410 and substantially mixed. Averaged and output. Note that the center of gravity at this time is on the third row, but the next mixed pixel is an image in which the fourth, sixth and eighth rows are mixed (the center of gravity is on the sixth row), and every three rows will be output. As a notation, the number of mixed pixels is shown in the numerator and the number of output line intervals is shown in the denominator. For example, in the example shown in FIG. 5A, since the number of mixed pixels is 3 and the number of output line intervals is 3, the vertical 3/3 mixture is described.

  FIG. 5B shows an operation example when the signals of two pixels in the vertical direction are mixed. As shown in FIG. 5B, the row selection switches 409_1 and 409_3 are selected, the signals of the pixels 205 in the first and third rows are output to the vertical output line (column output line) 410, and are substantially mixed and output. The Compared with the example shown in FIG. 5A, the signals of the pixels in the fifth row are not mixed, but the next image output is the mixed output of the fourth and sixth rows, and the next image output is 7,9. The mixed output of the line is obtained, and the output line interval number is 3, so that the vertical 2/3 mixture is obtained.

  FIG. 5C shows an example of readout without mixing of pixel signals in the vertical direction. In the example shown in FIG. 5C, the row selection switch 409_5 is selected, and the signal of the pixel in the fifth row is output to the vertical output line (column output line) 410. As shown in FIG. 5B, when signals for normal imaging are read out with vertical 2/3 pixel mixing, signals are not read out for the remaining 1/3 pixels. For this reason, it is possible to continue to read out the signal as shown in FIG. 5C after the scanning of reading out the signal as shown in FIG. That is, in the same frame, it is possible to read a signal for normal imaging with vertical 2/3 pixel mixture, and read an AF signal from different pixels.

  FIG. 6 is a diagram illustrating a state in which an AF signal is read and an AF signal is not read. The transition of time is shown by the t-axis, and data at the time of live view reading is shown in the upper part. The AF read data described later is also shown. The normal image vertical mixing number indicates a vertical pixel mixing method in reading a normal imaging (output image) signal. The presence or absence of AF readout indicates the presence or absence of AF readout and the readout timing when there is AF readout.

  Data 600 is obtained by reading for normal imaging with vertical 3/3 mixing, and the vertical 3/3 mixing state 604 continues for a while. At this time, there is no AF reading 607. Thereafter, when the shutter button 61 is half-pressed, an operation for AF processing is requested.

  When an operation for AF processing is required, readout for normal imaging is changed from, for example, vertical 3/3 mixing to vertical 2/3 mixing. Data 601 is obtained by performing normal imaging readout with vertical 2/3 mixing, and is performed after AF readout is performed for normal imaging readout from pixels that have not been readout by normal imaging readout. (Post-read). The read AF data is 603. AF post-reading 608 is continued until AF processing ends.

  When the AF process is completed, the readout for normal imaging returns from, for example, vertical 2/3 mixing to vertical 3/3 mixing. Data 602 is obtained by performing readout for normal imaging with vertical 3/3 mixing, and the vertical 3/3 mixing state 606 continues for a while. Further, a state 609 where there is no AF readout is obtained. When the AF processing is completed, the normal imaging readout method may be returned after one frame instead of the immediately following frame depending on the timing of resetting the pixels for normal imaging and the readout of the AF pixels. At this time, as shown by data 610 in FIG. 6, even after the AF processing is finished, the next frame is read for normal imaging with vertical 2/3 mixing, and then normal imaging with vertical 3/3 mixing is performed. Read-out is performed. The detailed operation when the AF process is finished and the reading for normal photographing is performed will be described in the second embodiment.

  FIG. 7 is a diagram illustrating an example of the readout position of each signal at the time of AF readout shown in FIG. With reference to FIG. 7A, an example in which the AF signal readout region is at the top of the pixel unit 208 will be described first. Among the pixel portions 208 of the image sensor 1400, there is a light-shielded optical black portion 700, and the effective pixel portion is 701. In the effective pixel portion 701, an area for reading a signal for normal imaging with vertical 2/3 mixing is defined as 702. Of the area from which the signal for normal imaging is not read out, the signal of the filled area 703 is read out for AF. Of the areas where signals for normal imaging are not read out, the unfilled area 704 is an area where signals are not read out as they are.

  FIG. 7B shows an example in which the AF signal readout region is in the center of the pixel portion 208. Among the areas from which signals for normal imaging are not read out, the filled area 703 is gathered in the central portion as compared with the example shown in FIG. Note that it is conceivable that the area from which AF signals are read out is changed according to the distance measuring point.

  Next, with reference to FIGS. 8 to 10, an example of driving at the time of reading a normal imaging signal and an AF signal will be described. FIG. 8 and FIG. 9 are timing charts showing driving examples when reading signals for normal imaging, and FIG. 10 is a timing chart showing driving examples when reading signals for AF. In the present embodiment, the image sensor 1400 reads the signal after resetting the FD in order to read by correlated double sampling.

  8 to 10, 406 — i indicates the state of the reset switch of the pixel 205 in the i-th row. 405A_i indicates the state of the transfer switch connected to the first photodiode 306A of the pixel 205 in the i-th row, and 405B_i indicates the transfer connected to the second photodiode 306B of the pixel 205 in the i-th row. Indicates the switch status. 409_i indicates the state of the row selection switch of the pixel 205 in the i-th row. Here, the reset switch 406 — i is in an on state (conducting state) when it is at a low level, and is in an off state (non-conducting state) when it is at a high level. In addition, the transfer switches 405A_i and 405B_i and the row selection switch 409_i are turned on (conductive state) when at a high level, and turned off (non-conductive state) when at a low level.

  FIG. 8 shows a timing chart when a signal for normal imaging is read with vertical 3/3 mixing. First, at timing T800, the system control circuit 50 turns on the reset switches 406_1, 406_3, and 406_5 via the TG 1800 to reset the FDs 407 of the pixels 205 in the first, third, and fifth rows. At timing T801, the system control circuit 50 selects (turns on) the row selection switches 409_1, 409_3, and 409_5 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the first, third, and fifth rows and stored in the column circuit 207.

  At timing T802, the system control circuit 50 turns on the transfer switches 405A_1, 405A_3, 405A_5 and the transfer switches 405B_1, 405B_3, 405B_5 through the TG 1800 at the same time. As a result, the charges accumulated in the photodiodes 306A and 306B in the pixels 205 in the first, third and fifth rows are changed so that the signal of the FD 407 of the pixels 205 in the first, third and fifth rows becomes an A + B image signal. It is transferred to the FD 407.

  At this time, since the row selection switches 409_1, 409_3, and 409_5 remain selected (turned on), a signal obtained by substantially mixing and averaging the A + B image signals via the vertical output line (column output line) 410 is used as the column circuit 207. Sent to. The read A + B image signal is output from the image sensor 1400 by subtracting the reset signal previously read and stored in the column circuit 207. After the output, the system control circuit 50 cancels the selection of the row selection switches 409_1, 409_3, and 409_5 via the TG 1800 and turns them off.

  At timing T803, the system control circuit 50 turns on the reset switches 406_4, 406_6, and 406_8 via the TG 1800 to reset the FDs 407 of the pixels 205 in the fourth, sixth, and eighth rows. At timing T804, the system control circuit 50 selects (turns on) the row selection switches 409_4, 409_6, and 409_8 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the fourth, sixth, and eighth rows and stored in the column circuit 207.

  At timing T805, the system control circuit 50 simultaneously turns on the transfer switches 405A_4, 405A_6, 405A_8 and the transfer switches 405B_4, 405B_6, 405B_8 via the TG 1800. As a result, the charges accumulated in the photodiodes 306A and 306B in the pixels 205 in the fourth, sixth, and eighth rows are changed so that the signal of the FD 407 of the pixels 205 in the fourth, sixth, and eighth rows becomes an A + B image signal. It is transferred to the FD 407.

  At this time, since the row selection switches 409_4, 409_6, and 409_8 remain selected (turned on), a signal obtained by substantially mixing and averaging the A + B image signals via the vertical output line (column output line) 410 is used as the column circuit 207. Sent to. The read A + B image signal is output from the image sensor 1400 by subtracting the reset signal previously read and stored in the column circuit 207. After the output, the system control circuit 50 cancels the selection of the row selection switches 409_4, 409_6, and 409_8 through the TG 1800 and turns them off.

  At timing T806, the system control circuit 50 resets the FDs 407 of the pixels 205 in the seventh, ninth, and eleventh rows by turning on the reset switches 406_7, 406_9, and 406_11 through the TG 1800, though not all are illustrated. At timing T807, the system control circuit 50 selects (turns on) the row selection switches 409_7, 409_9, and 409_11 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the seventh, ninth, and eleventh rows and stored in the column circuit 207.

  At timing T808, the system control circuit 50 turns on the transfer switches 405A_7, 405A_9, and 405A_11 and the transfer switches 405B_7, 405B_9, and 405B_11 through the TG 1800 at the same time. As a result, the charges accumulated in the photodiodes 306A and 306B in the pixels 205 in the seventh, ninth and eleventh rows are changed so that the signal of the FD 407 of the pixels 205 in the seventh, ninth and eleventh rows becomes an A + B image signal. It is transferred to the FD 407.

At this time, since the row selection switches 409_7, 409_9, and 409_11 remain selected (turned on), the signal obtained by substantially mixing and averaging the A + B image signals via the vertical output line (column output line) 410 is used as the column circuit 207. Sent to. The read A + B image signal is output from the image sensor 1400 by subtracting the reset signal previously read and stored in the column circuit 207. After the output, the system control circuit 50 cancels the selection of the row selection switches 409_7, 409_9, and 409_11 via the TG 1800 and turns them off.
This process is performed for the number of rows from which signals are read in order to display an image in a live view operation.

  FIG. 9 shows a timing chart when a signal for normal imaging is read with vertical 2/3 mixing. First, at timing T900, the system control circuit 50 turns on the reset switches 406_1 and 406_3 via the TG 1800 to reset the FD 407 of the pixels 205 in the first and third rows. At timing T901, the system control circuit 50 selects (turns on) the row selection switches 409_1 and 409_3 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the first and third rows and stored in the column circuit 207.

  At timing T902, the system control circuit 50 turns on the transfer switches 405A_1 and 405A_3 and the transfer switches 405B_1 and 405B_3 through the TG 1800 at the same time. As a result, the charges accumulated in the photodiodes 306A and 306B in the pixels 205 in the first and third rows are transferred to the FD 407 so that the signal of the FD 407 of the pixels 205 in the first and third rows becomes an A + B image signal. The

  At this time, since the row selection switches 409_1 and 409_3 remain selected (turned on), a substantially averaged signal of the A + B image signals is sent to the column circuit 207 via the vertical output line (column output line) 410. It is done. The read A + B image signal is output from the image sensor 1400 by subtracting the reset signal previously read and stored in the column circuit 207. After the output, the system control circuit 50 cancels the selection of the row selection switches 409_1 and 409_3 via the TG 1800 and turns them off.

  At timing T903, the system control circuit 50 turns on the reset switches 406_4 and 406_6 via the TG 1800 to reset the FDs 407 of the pixels 205 in the fourth and sixth rows. At timing T904, the system control circuit 50 selects (turns on) the row selection switches 409_4 and 409_6 via the TG 1800 in order to read out the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the fourth and sixth rows and stored in the column circuit 207.

  At timing T905, the system control circuit 50 turns on the transfer switches 405A_4 and 405A_6 and the transfer switches 405B_4 and 405B_6 through the TG 1800 at the same time. As a result, the charges accumulated in the photodiodes 306A and 306B in the pixels 205 in the fourth and sixth rows are transferred to the FD 407 so that the signals of the FD 407 of the pixels 205 in the fourth and sixth rows become A + B image signals. The

  At this time, since the row selection switches 409_4 and 409_6 remain selected (turned on), a substantially averaged signal of the A + B image signals is sent to the column circuit 207 via the vertical output line (column output line) 410. It is done. The read A + B image signal is output from the image sensor 1400 by subtracting the reset signal previously read and stored in the column circuit 207. After the output, the system control circuit 50 cancels the selection of the row selection switches 409_4 and 409_6 via the TG 1800 and turns them off.

  At timing T906, the system control circuit 50 resets the FDs 407 of the pixels 205 in the seventh and ninth rows by setting the reset switches 406_7 and 406_9 to an on state (not shown) via the TG 1800. At timing T907, the system control circuit 50 selects (turns on) the row selection switches 409_7 and 409_9 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the seventh and ninth rows and stored in the column circuit 207.

  At timing T908, the system control circuit 50 turns on the transfer switches 405A_7 and 405A_9 and the transfer switches 405B_7 and 405B_9 at the same time through the TG 1800, though not all are illustrated. As a result, the charges accumulated in the photodiodes 306A and 306B in the pixels 205 in the seventh and ninth rows are transferred to the FD 407 so that the signal of the FD 407 of the pixels 205 in the seventh and ninth rows becomes an A + B image signal. The

At this time, since the row selection switches 409_7 and 409_9 remain selected (turned on), a substantially averaged signal of the A + B image signals is sent to the column circuit 207 via the vertical output line (column output line) 410. It is done. The read A + B image signal is output from the image sensor 1400 by subtracting the reset signal previously read and stored in the column circuit 207. After the output, the system control circuit 50 cancels the selection of the row selection switches 409_7 and 409_9 via the TG 1800 and turns them off.
This process is performed for the number of rows from which signals are read in order to display an image in a live view operation.

  FIG. 10 shows a timing chart when reading signals for AF. At timing T1000, the system control circuit 50 turns on the reset switch 406_5 via the TG 1800 to reset the FD 407 of the pixels 205 in the fifth row. At timing T1001, the system control circuit 50 selects (turns on) the row selection switch 409_5 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the fifth row and stored in the column circuit 207.

  At timing T1002, the system control circuit 50 turns on the transfer switch 405A_5 via the TG 1800 and transfers the charge (A image signal) accumulated in the first photodiode 306A to the FD 407 in the pixel 205 in the fifth row. To do. Since the row selection switch 409_5 remains selected (turned on), the A image signal is sent to the column circuit 207. The read A image signal is output from the image sensor 1400 by subtracting the reset signal that has been read first and stored in the column circuit 207. Thereafter, the row selection switch 409_5 is released (turned off).

  At timing T1003, the system control circuit 50 turns on the reset switch 406_5 via the TG 1800 to reset the FD 407 of the pixels 205 in the fifth row again. At timing T1004, the system control circuit 50 selects (turns on) the row selection switch 409_5 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the fifth row and stored in the column circuit 207.

  At timing T1005, the system control circuit 50 turns on the transfer switch 405B_5 via the TG 1800 and transfers the charge (B image signal) accumulated in the second photodiode 306B to the FD 407 in the pixel 205 in the fifth row. To do. Since the row selection switch 409_5 remains selected (turned on), the B image signal is sent to the column circuit 207. The read B image signal is output from the image sensor 1400 by subtracting the reset signal previously read and stored in the column circuit 207. Thereafter, the row selection switch 409_5 is released (turned off).

  At timing T1006, the system control circuit 50 turns on the reset switch 406_8 via the TG 1800 to reset the FD 407 of the pixels 205 in the eighth row. At timing T1007, the system control circuit 50 selects (turns on) the row selection switch 409_8 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the eighth row and stored in the column circuit 207.

  At timing T1008, the system control circuit 50 turns on the transfer switch 405A_8 via the TG 1800, and transfers the charge (A image signal) accumulated in the first photodiode 306A to the FD 407 in the pixel 205 in the eighth row. To do. Since the row selection switch 409_8 remains selected (turned on), the A image signal is sent to the column circuit 207. The read A image signal is output from the image sensor 1400 by subtracting the reset signal that has been read first and stored in the column circuit 207. Thereafter, the row selection switch 409_8 is released (turned off).

  At timing T1009, the system control circuit 50 turns on the reset switch 406_8 via the TG 1800 to reset the FD 407 of the pixels 205 in the eighth row again. At timing T1010, the system control circuit 50 selects (turns on) the row selection switch 409_8 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the eighth row and stored in the column circuit 207.

  At timing T1011, the system control circuit 50 turns on the transfer switch 405B_8 via the TG 1800, and transfers the charge (B image signal) accumulated in the second photodiode 306B to the FD 407 in the pixels 205 in the eighth row. To do. Since the row selection switch 409_8 remains selected (turned on), the B image signal is sent to the column circuit 207. The read B image signal is output from the image sensor 1400 by subtracting the reset signal previously read and stored in the column circuit 207. Thereafter, the row selection switch 409_5 is released (turned off).

  At timing T1012, the system control circuit 50 turns on a reset switch 406_11 (not shown) via the TG 1800 to reset the FD 407 of the pixel 205 in the eleventh row. At timing T1013, the system control circuit 50 selects (turns on) the row selection switch 409_11 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the eleventh row and stored in the column circuit 207.

  At timing T1014, the system control circuit 50 turns on the transfer switch 405A_11 (not shown) via the TG 1800, and charges (A image signal) accumulated in the first photodiode 306A in the pixels 205 in the eleventh row. Transfer to FD 407. Since the row selection switch 409_11 remains selected (turned on), the A image signal is sent to the column circuit 207. The read A image signal is output from the image sensor 1400 by subtracting the reset signal that has been read first and stored in the column circuit 207. Thereafter, the row selection switch 409_11 is released (turned off).

  At timing T1015, the system control circuit 50 turns on a reset switch 406_11 (not shown) via the TG 1800 to reset the FD 407 of the pixel 205 in the 11th row again. At timing T1016, the system control circuit 50 selects (turns on) the row selection switch 409_11 via the TG 1800 in order to read the signal of the FD 407 after reset. As a result, the reset signal is read out from the pixels 205 in the eleventh row and stored in the column circuit 207.

At timing T1017, the system control circuit 50 turns on the transfer switch 405B_11 (not shown) via the TG 1800, and charges (B image signal) accumulated in the second photodiode 306B in the pixels 205 in the eleventh row. Transfer to FD 407. Since the row selection switch 409_11 remains selected (turned on), the B image signal is sent to the column circuit 207. The read B image signal is output from the image sensor 1400 by subtracting the reset signal read out first and stored in the column circuit 207. Thereafter, the row selection switch 409_11 is released (turned off).
This process is repeated for the number of rows from which AF signals are read.

  FIG. 11 is a flowchart illustrating an operation example of the imaging apparatus according to the present embodiment. In step S1100, system control circuit 50 determines whether or not there is an AF signal readout request in the readout of signals in the live view operation.

  When the system control circuit 50 determines that there is an AF signal readout request, the system control circuit 50 performs both readout of the normal imaging (output image) signal and readout of the AF (focus detection processing) signal. Drive control is performed so that signal readout is performed in the first readout mode. In step S1103, the system control circuit 50 performs drive control so as to read out signals for normal imaging with vertical 2/3 mixing. In accordance with this control, the image sensor 1400 reads out signals for normal imaging with vertical 2/3 mixing. After that, in step S1104, the system control circuit 50 performs drive control so as to read out the AF signal, and the image sensor 1400 reads out the AF signal. When reading of the AF signal is completed, the process proceeds to step S1102.

  Further, when the system control circuit 50 determines that there is no AF signal readout request, the system control circuit 50 reads out the normal imaging (output image) signal and the AF (focus detection processing) signal. Drive control is performed so that signal readout is performed in the second readout mode. In step S1101, the system control circuit 50 performs drive control so as to read out signals for normal imaging with vertical 3/3 mixing. In accordance with this control, the image sensor 1400 reads out signals for normal imaging with vertical 3/3 mixing. Then, it progresses to step S1102.

  In step S1102, the system control circuit 50 determines whether or not the live view operation is finished. If the system control circuit 50 determines that the live view operation has not ended, the process returns to step S1100 to determine again whether there is a request for reading an AF signal. On the other hand, when the system control circuit 50 determines that the live view operation has ended, the operation ends.

  As described above, the number of pixels to be vertically mixed in the readout of the normal imaging signal is switched depending on whether or not the AF signal is readout. In the example described above, normal AF signal reading is performed with vertical 2/3 mixing when there is AF signal readout, and normal vertical 3/3 mixing when there is no AF signal readout. Reading out signals for imaging. As a result, it is possible to increase the number of pixels to be vertically mixed in reading of a signal for normal imaging when AF processing is performed using an imaging device capable of pupil-division focus detection and when AF processing is not performed. . Therefore, it is possible to suppress a decrease in the number of pixels to be mixed by reading a signal for normal imaging, and even in an image having a high spatial frequency, a good image in which noise such as moire is suppressed and noise is suppressed can be obtained. Can be obtained.

  In the above description, the example in which the signals of the plurality of pixels are mixed by turning on the plurality of row selection switches 409 and connecting the plurality of pixels 205 via the vertical output line (column output line) 410 has been shown. However, the present invention is not limited to this. For example, as described below, mixing may be performed by connecting FDs 407 of a plurality of pixels 205.

  FIG. 12 is a diagram for describing an image sensor 1400 that performs signal mixing by connecting floating diffusion portions (FDs) of the pixel 205 to each other. FIG. 12 illustrates a configuration for realizing mixing by connecting FDs, taking pixels 205_1, 205_3, and 205_5 in the first, third, and fifth rows as an example. The nodes of the FDs 407 of the pixels 205_1, 205_3, and 205_5 are connected to each other through FD mixing switches 1201 and 1202. In the case of performing pixel mixing, mixing is realized by turning on the switches 1201 and 1202 (conductive state). 12, the components other than the reset switch 406, the FD 407, and the source follower amplifier 408 are not illustrated, but are configured in the same manner as the pixel 205 illustrated in FIG. .

  FIG. 13 is a timing chart when the signal is read by vertical 3/3 mixing in the imaging device 1400 that performs signal mixing by connecting the FDs of the pixels 205. In FIG. 13, the operation is shown by taking the configuration shown in FIG. 12 as an example.

  First, at timing T1300, the system control circuit 50 turns on the reset switches 406_1, 406_3, and 406_5 via the TG 1800 to reset the FDs 407 of the pixels 205 in the first, third, and fifth rows. At this time, the FD mixing switches 1201 and 1202 are already on. At timing T1301, in order to read out the signal of the FD 407 after reset, the system control circuit 50 selects (turns on) the row selection switch 409_1 via the TG 1800, and the read reset signal is stored in the column circuit 207. The

  At timing T1302, the system control circuit 50 turns on the transfer switches 405A_1, 405A_3, 405A_5 and the transfer switches 405B_1, 405B_3, 405B_5 through the TG 1800 at the same time. As a result, the charges accumulated in the photodiodes 306A and 306B in the pixels 205 in the first, third and fifth rows are changed so that the signal of the FD 407 of the pixels 205 in the first, third and fifth rows becomes an A + B image signal. It is transferred to the FD 407.

  At this time, since the row selection switch 409_1 remains selected (turned on), the A + B image signal that is approximately mixed and averaged by FD mixing is sent to the column circuit 207. The read A + B image signal is output from the image sensor 1400 by subtracting the reset signal previously read and stored in the column circuit 207. After the output, the system control circuit 50 cancels the selection of the row selection switch 409_1 via the TG 1800 and turns it off.

  FIG. 13 shows an example in which signals are read by vertical 3/3 mixing, but by controlling the FD mixing switches 1201 and 1202, signals are read by vertical 2/3 mixing or for AF. It is possible to read out the signal. For example, when the FD mixing switches 1201 and 1202 are both turned on, signals for normal imaging with vertical 3/3 mixing can be read. Further, for example, when the FD mixing switch 1201 is turned on and the FD mixing switch 1202 is turned off, the signal for normal imaging in the vertical 2/3 mixing and the signal for AF can be read. it can.

  As described above, even when FDs are connected and FD mixing is performed when the pixel signals are vertically mixed, substantially the same function as substantially mixing by row selection can be realized. Therefore, similarly to the above-described mixing by row selection, it is possible to suppress a decrease in the number of pixels to be mixed by reading a signal for normal imaging, and to generate noise such as moire even for an image having a high spatial frequency. A good image with suppressed noise can be obtained.

(Second Embodiment)
In the second embodiment, a signal reading state when the AF signal is read and the AF signal is not read will be described. FIG. 14 shows a transition state when the shutter speed of the normal captured image is longer than a predetermined time. In FIG. 14, the transition of time is shown by the t-axis, and the presence / absence of readout of the AF signal, the timing of the vertical synchronization signal (VD), and the scanning line for signal readout or reset (described later). The same applies to FIGS. 15 and 16). The system control circuit 50 reads out signals from the image sensor 1400 and scans the pixels through the TG 1800.

  AF signal readout is performed after readout of a normal imaging signal In the Nth frame, which is the last frame during post-AF readout, the timing for AF pixel reset scanning 1408 corresponds to the AF signal accumulation time Start with. Reading of a signal for normal imaging 1401 is performed with vertical 2/3 mixing, and scanning is started immediately after the vertical synchronization signal (VD) is asserted. Immediately after the scanning of the normal imaging signal readout 1401 is completed, the scanning of the AF signal readout 1409 is started.

  In the Nth frame, the pixel reset scanning 1402 for the normal imaging signal readout 1403 in the (N + 1) th frame reads out the normal imaging signal in the vertical 2/3 mixture. It starts at the timing according to the shutter time. FIG. 14 illustrates a case where the normal imaging pixel reset scanning 1402 starts earlier than the end timing of the AF signal readout scanning 1409. In this case, the pixel reset scanning 1402 needs to be performed on a pixel from which a normal imaging signal is read out by vertical 2/3 mixing so as not to prevent reading of the AF signal.

  In the (N + 1) -th frame, which is the first frame without AF readout, the normal imaging signal readout 1403 is performed with vertical 2/3 mixing, and scanning starts immediately after the vertical synchronization signal (VD) is asserted. Is done. The pixel reset scanning 1404 for reading the normal imaging signal 1405 of the (N + 2) th frame is started at a timing corresponding to the shutter time in the vertical 3/3 mixing.

  Next, in the (N + 2) th frame, the normal imaging signal readout 1405 is performed with vertical 3/3 mixing, and scanning is started immediately after the vertical synchronization signal (VD) is asserted. The pixel reset scanning 1406 for reading the normal imaging signal 1407 of the (N + 3) th frame is started at the timing corresponding to the shutter time in the vertical 3/3 mixing. Next, in the (N + 3) th frame, the signal 1407 for normal imaging is read by vertical 3/3 mixing, and scanning is started immediately after the vertical synchronization signal (VD) is asserted.

  FIG. 15 shows a transition state when the shutter speed of the normal captured image is shorter than a predetermined time. The system control circuit 50 reads out signals from the image sensor 1400 and scans for pixel reset via the TG 1800.

  AF signal readout is performed after readout of a normal imaging signal In the Nth frame, which is the last frame during post-AF readout, the timing of AF pixel reset scanning 1508 according to the AF signal accumulation time Start with. Reading signal 1501 for normal imaging is performed by vertical 2/3 mixing, and scanning is started immediately after the vertical synchronization signal (VD) is asserted. Immediately after the scanning of the normal imaging signal readout 1501 is completed, scanning of the AF signal readout 1509 is started.

  In the Nth frame, the pixel reset scanning 1502 for the normal imaging signal readout 1503 in the (N + 1) th frame reads pixels for normal imaging with vertical 3/3 mixing. It starts at the timing according to the shutter time. In FIG. 15, the pixel reset scanning 1502 does not affect the AF signal readout 1509 because the start of the normal imaging pixel reset scanning 1502 is later than the end timing of the AF signal readout scanning 1509. It can be done with vertical 3/3 mixing.

  In the (N + 1) -th frame, which is the first frame without AF readout, normal imaging signal readout 1503 is performed with vertical 3/3 mixing, and scanning starts immediately after the vertical synchronization signal (VD) is asserted. Is done. The pixel reset scanning 1504 for reading the normal imaging signal 1505 for the (N + 2) th frame is started at the timing corresponding to the shutter time in the vertical 3/3 mixing.

  Next, in the (N + 2) th frame, the normal imaging signal readout 1505 is performed by vertical 3/3 mixing, and scanning is started immediately after the vertical synchronization signal (VD) is asserted. The pixel reset scanning 1506 for reading the normal imaging signal 1507 in the (N + 3) th frame is started at the timing corresponding to the shutter time in the vertical 3/3 mixing. Next, in the (N + 3) th frame, the signal 1507 for normal imaging is read out with vertical 3/3 mixing, and scanning is started immediately after the vertical synchronization signal (VD) is asserted.

  FIG. 16 shows an example in which the AF signal is read before the normal imaging signal (AF destination reading). In AF destination reading, normal imaging signals are read after AF signals are read.

  In the Nth frame, immediately after the vertical synchronization signal (VD) is asserted, scanning of the AF signal readout 1600 is started. After the AF signal readout 1600 is completed, scanning of the normal imaging signal readout 1603 is started with vertical 2/3 mixing. After that, the pixel reset scanning 1604 for reading the normal imaging signal 1605 in the (N + 1) th frame corresponds to the shutter time for the pixel from which the normal imaging signal is read with the vertical 2/3 mixing. Start with timing. Further, the pixel reset scanning 1601 for the AF signal readout 1602 of the (N + 1) th frame is started at a timing corresponding to the AF signal accumulation time.

  In the (N + 1) th frame, immediately after the vertical synchronization signal (VD) is asserted, scanning of the AF signal readout 1602 is started. After the scanning of the AF signal readout 1602 is completed, the scanning of the normal imaging signal readout 1605 is started with vertical 2/3 mixing. Thereafter, the pixel reset scanning 1606 for reading the normal imaging signal 1607 in the (N + 2) th frame is started at the timing corresponding to the shutter time in the vertical 3/3 mixing.

  In the (N + 2) th frame, the same time as the start of the readout scanning 1605 for the normal imaging signal from the falling edge of the vertical synchronization signal (VD) in the (N + 1) frame, the (N + 2) th frame is also waited for normal imaging. Scanning of the signal 1607 is started. Thereafter, a pixel reset scanning 1608 for reading the normal imaging signal 1609 in the (N + 3) th frame is started at a timing corresponding to the shutter time in the vertical 3/3 mixing. In the (N + 3) th frame, the same time as the start of the readout scan 1607 for the normal imaging signal from the falling edge of the vertical synchronization signal (VD) in the (N + 2) frame, the (N + 3) th frame is also waited for the normal imaging. Scanning of the signal 1609 is started.

  FIG. 17 shows a flowchart when switching from the AF signal readout to the AF signal readout. In the final frame in which the AF signal is read, the system control circuit 50 determines whether or not the AF signal is read before the normal imaging signal is read (S1700). When the system control circuit 50 determines that the AF signal is read after the normal imaging signal is read, the system control circuit 50 determines whether or not the shutter time of the normal captured image is shorter than a predetermined time (S1701). ).

  When the system control circuit 50 determines that the shutter speed of the normal captured image is not shorter than the predetermined time, the normal imaging reset scanning prevents reading of the last AF signal, and therefore the normal imaging reset is not performed. Scan with vertical 2/3 mixing (S1704). After that, a signal for normal imaging is read with vertical 2/3 mixing (S1705). After that, that is, in the next frame after the first frame when the AF signal is read out and the AF signal is not read out, the signal shifts to the signal reading by the vertical 3/3 mixing.

  On the other hand, when the system control circuit 50 determines that the normal imaging signal is read after the AF signal is read, or when the shutter time of the normal captured image is determined to be shorter than the predetermined time, It progresses to step S1702. Then, immediately after switching from AF signal readout to AF signal readout is not performed, normal imaging reset scanning is performed with vertical 3/3 mixing (S1702), and then normal imaging readout scanning is performed. Is also carried out with vertical 3/3 mixing (S1703).

  In the second embodiment, the transition of the vertical mixing in the readout of the normal imaging signal when switching from the readout of the AF signal to the absence of the readout of the AF signal has been described. As described above, according to the second embodiment, both the AF signal reading and the normal imaging signal reading can be performed without waste without interfering with the respective processes.

(Third embodiment)
In the third embodiment, whether to read signals with vertical 3/3 mixing or with vertical 2/3 mixing during live view operation when AF signals are not read out depends on the subject. An example of selection is shown.

  FIG. 18 shows an example of a subject and a vertical mapping obtained by averaging the levels in the column direction. FIG. 18A is a photograph of a natural landscape, and the vertical map also changes gently. FIG. 18B is a photograph of the inside of a building as a subject, and the blinds in the window become very thin lines, and the mapping between the places where sunlight is incident and where the sunlight is incident is large in a narrow space. You can see that it is changing.

  For a subject such as the example shown in FIG. 18A, there is a possibility that the merit of reading signals with vertical 3/3 mixing cannot be greatly obtained. In contrast, for a subject having a high spatial frequency as in the example shown in FIG. 18B, the merit of reading signals with the vertical 3/3 mixing shown in the first embodiment can be obtained.

  Therefore, in this embodiment, the system control circuit 50 analyzes the spatial frequency of the image, and switches the setting of the number of pixels to be vertically mixed based on the analysis result. The spatial frequency analysis is performed using discrete cosine transform (DCT) or the like. If the effect is likely to be obtained even when the spatial frequency is low, signal readout with vertical 3/3 mixing may be performed. On the other hand, when different effects are obtained in the image, the signal may be read out in the vertical 2/3 mixture even if the spatial frequency is high.

  FIG. 19 is a flowchart illustrating an operation example of the imaging apparatus capable of switching the number of pixels to be vertically mixed according to the subject. When the LV operation is started, first, signal reading is performed with vertical 2/3 mixing as signal reading for normal imaging (S1900). Next, the system control circuit 50 determines whether or not there is an AF signal readout request in the readout of signals in the live view operation (S1901).

  When the system control circuit 50 determines that there is an AF signal readout request, the system control circuit 50 performs both readout of the normal imaging (output image) signal and readout of the AF (focus detection processing) signal. Drive control is performed so that signal readout is performed in the first readout mode. The system control circuit 50 performs drive control so as to read out signals for normal imaging with vertical 2/3 mixing, and reads out signals for normal imaging with vertical 2/3 mixing (S1905). Thereafter, the system control circuit 50 performs drive control so as to read out the AF signal, and the AF signal is read out (S1906). When reading of the AF signal is completed, the process proceeds to step S1907.

  If the system control circuit 50 determines that there is no AF signal readout request, the system control circuit 50 reads out the normal imaging (output image) signal and does not read out the AF (focus detection processing) signal. Drive control is performed so that signal readout is performed in the second readout mode. Next, the system control circuit 50 checks the vertical spatial frequency of the first image for normal imaging read (S1902).

  When the system control circuit 50 determines that the spatial frequency is higher than a predetermined value, the system control circuit 50 performs drive control so as to read a signal for normal imaging with vertical 3/3 mixing, and for normal imaging with vertical 3/3 mixing. Is read out (S1903). On the other hand, when the system control circuit 50 determines that the spatial frequency is not higher than the predetermined value, the system control circuit 50 performs drive control so that the signal for normal imaging is read out by the vertical 2/3 mixing, and the vertical 2/3 mixing is performed. Reading of signals for normal imaging is performed (S1904). When reading of the signal for normal imaging in steps S1903 and S1904 is completed, the process proceeds to step S1907.

  Subsequently, the system control circuit 50 determines whether or not the live view operation is finished (S1907). If the system control circuit 50 determines that the live view operation has not ended, the process returns to step S1901 to determine again whether there is a request to read an AF signal. On the other hand, when the system control circuit 50 determines that the live view operation has ended, the operation ends.

  In the third embodiment, the spatial frequency of the subject is analyzed, and the number of pixels to be vertically mixed in the signal readout for normal imaging when the AF signal readout is not performed is changed according to the result obtained by the analysis. An example to do. In this way, an optimum reading method can be selected as necessary, and a good image in which noise such as moire is suppressed can be obtained.

(Other embodiments of the present invention)
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 the 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.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

DESCRIPTION OF SYMBOLS 100: Imaging device 200: Recording medium 300: Lens unit 50: System control circuit 61: Shutter switch 72: Image processing part 73: Autofocus calculating part 74: Subject analysis part 310: Lens 320: Lens control part 1200: Liquid crystal monitor 1400 : Image sensor 1800: Timing generator (TG) 203: Horizontal scanning circuit 204: Vertical scanning circuit 205: Pixel 206: Column gain amplifier 207: Column circuit 208: Pixel unit 304: Microlens 306A, 306B: Photodiode (photoelectric conversion element) 405A, 405B: Transfer switch 406: Reset switch 407: Floating diffusion part (FD) 408: Source follower amplifier 409: Row selection switch 410: Vertical output line (column output) line)

Claims (10)

An image sensor in which a plurality of pixels each having a plurality of photoelectric conversion elements are arranged two-dimensionally;
Processing means for performing focus detection processing based on a signal from the image sensor;
A first reading mode for reading a signal for focus detection processing and a signal for output image from the image sensor; and a second for reading the signal for output image without reading the signal for focus detection processing from the image sensor. Control means for driving and controlling the imaging device in any one of the readout modes,
When the control means mixes and reads out the output signals of a plurality of pixels in the column direction from the image sensor, the control means determines the number of pixels to be read out by mixing the output signals in the first readout mode and the second readout mode. An image pickup apparatus that is controlled to be different.   2. The imaging apparatus according to claim 1, wherein the number of pixels read out by mixing output signals in the second read mode is larger than the number of pixels read out by mixing output signals in the first read mode.   3. The control unit according to claim 1, wherein the control unit controls the number of pixels read out by mixing output signals by controlling the number of pixels simultaneously connected to a column output line that outputs a signal of the pixels. Imaging device.   The imaging apparatus according to claim 1, wherein the control unit controls the number of pixels read out by mixing output signals by controlling a switch that connects floating diffusion portions of a plurality of pixels.   The pixel for reading out the signal for the output image and the pixel for reading out the signal for focus detection processing are made different in a frame in the first readout mode. The imaging device described.   When shifting from the first readout mode to the second readout mode, the first output image signal readout in the second readout mode is performed by mixing output signals in the first readout mode. The imaging apparatus according to claim 1, wherein output signals having the same number of pixels as the number of pixels are mixed and read out.   When the pixel for reading out the first output image signal in the second readout mode is reset before the final readout of the focus detection processing signal in the first readout mode is completed, The first output image signal in the second readout mode is read out by mixing output signals having the same number of pixels as the number of pixels read out by mixing the output signals in the first readout mode. The imaging device according to claim 6. Subject analysis means for measuring the spatial frequency of an image of the subject,
8. The control unit according to claim 1, wherein the control unit changes the number of pixels read out by mixing output signals in the first readout mode based on a result of the subject analysis unit. Imaging device.   9. The imaging apparatus according to claim 8, wherein when the spatial frequency of an image obtained by photographing a subject is high, the number of pixels read out by mixing output signals in the first readout mode is increased. A control method for an image pickup apparatus including an image pickup element in which a plurality of pixels each having a plurality of photoelectric conversion elements are two-dimensionally arranged,
A processing step of performing focus detection processing based on a signal from the image sensor;
A first reading mode for reading a signal for focus detection processing and a signal for output image from the image sensor; and a second for reading the signal for output image without reading the signal for focus detection processing from the image sensor. A control step of driving and controlling the imaging device in any one of the readout modes of
In the control in the control step, when the output signals of a plurality of pixels are mixed and read from the image sensor in the column direction, the output signals are mixed and read in the first readout mode and the second readout mode. A control method for an image pickup apparatus, comprising control for varying the number of pixels.

Images