Imaging device, signal processing method

Abstract

This imaging device is configured to comprise: an imaging element equipped with photodiode division pixels including first and second photodiode pixels that output mutually different pixel signals; and a signal processing unit that, when an output value of a pixel signal becomes a saturation value, performs a saturation coping process for correcting the output value on the basis of the saturation value and a predicted output value.

Description

Technical Field

[0001] The present technology relates to an imaging device including an imaging element having a pixel group that outputs a phase difference signal, and a signal processing method thereof.

Background Art

[0002] Some imaging devices are provided with a function of acquiring focus information about a subject in order to perform autofocus (hereinafter sometimes referred to as "AF") control. For example, those having pixels for detecting focus in an imaging element are known. In Patent Document 1, in the case of performing focus detection by reading out a plurality of image signals obtained by pupil division in an imaging element, a technique is disclosed that enables focus detection by performing an operation of replacing a signal that has caused saturation (overflow) regardless of the symmetry of pupil division with a limit value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to detect a focused state, it is known to use a single pixel constituting an image as a photodiode (hereinafter sometimes referred to as "PD") divided pixel. This PD divided pixel is configured by dividing and arranging a pair of PD pixels on the left and right. In the case of this PD-divided pixel, a plurality of pupil-divided image signals (pixel values) can be read out. However, if an overflow occurs in one of the PD pixels, the balance of the output values of the left and right PD pixels will be different from the original state, and it will be impossible to accurately obtain the defocus amount. In the method of Patent Document 1 mentioned above, although it is possible to perform focus detection on a saturated signal, it cannot be said to be sufficient in terms of detection accuracy. Therefore, in the present technology, sufficient detection accuracy can be obtained even when an overflow occurs in an image pickup device having PD-divided pixels.

Means for Solving the Problem

[0005] The imaging device according to the present technology includes an image pickup device having a photodiode-divided pixel including a first photodiode pixel and a second photodiode pixel that output different pixel signals, respectively, and a signal processing unit that performs saturation corresponding processing for correcting an output value based on the saturation value and an output prediction value when the output value of the pixel signal becomes a saturation value. The output value of the image signal from the photodiode (PD) pixel is limited by a saturation threshold value, which is the maximum value when the amount of charge due to light reception overflows. Therefore, when an overflow occurs, the output value of the PD pixel is not an accurate value. In this case, saturation corresponding processing for correcting the output value is performed.

[0006] In the imaging device of the present technology described above, it is conceivable that the saturation corresponding processing includes a process of calculating a difference value between the output prediction value and the saturation value. Calculate the difference between the output prediction value and the saturation value and use it to correct the output value.

[0007] In the imaging device of the present technology described above, in the saturation corresponding processing, it is conceivable to calculate a difference value between the output prediction value and the saturation value for one of the first photodiode pixel and the second photodiode pixel. In a photodiode divided pixel, there is an event where the photodiode pixels on one side overflow. To address this, the difference between the output predicted value and the saturation value is calculated for the overflowing photodiode pixel on one side and used to correct the output value.

[0008] In the imaging device of the present technology described above, in the saturation handling process, it is conceivable to perform a process of adding the difference value calculated for the photodiode pixel on one side to the output value of the photodiode pixel on one side and subtracting the difference value from the output value of the photodiode pixel on the other side. There is a structure in which, when one of the photodiode pixels in a photodiode divided pixel overflows, the excess charge leaks into the other photodiode pixel side. In that case, the amount of leakage is corrected.

[0009] In the imaging device of the present technology described above, it is conceivable to include a control unit that determines the in-focus state and causes the signal processing unit to execute the saturation handling process according to the in-focus state. In the autofocus operation, for example, when it reaches a substantially in-focus state, the saturation handling process is performed.

[0010] In the imaging device of the present technology described above, the control unit first performs autofocus control based on the defocus amount obtained using the output value of the first photodiode pixel and the output value of the second photodiode pixel without causing the signal processing unit to execute the saturation handling process. After the conditions for the in-focus state are satisfied, the control unit performs autofocus control based on the defocus amount obtained using the output value of the first photodiode pixel and the output value of the second photodiode pixel in a state where the signal processing unit is caused to execute the saturation handling process. First, the autofocus control is used to roughly approach the in-focus state without performing the saturation handling process, and then the autofocus control is performed in a state where the saturation handling process is performed.

[0011] In the imaging device of the present technology described above, it is conceivable that the output predicted value is a value obtained based on the light reception angle characteristics of the first photodiode pixel and the second photodiode pixel and lens information. Since the light reception angle characteristics are known, if lens information such as lens vignetting is acquired for the attached lens barrel, the output predicted value can be obtained.

[0012] In the imaging device of the present technology described above, it is an imaging device capable of mounting an interchangeable lens barrel, and it is conceivable that the lens information is received from the lens barrel. In the case of an interchangeable lens, acquire lens information according to the lens barrel so that the output predicted value can be obtained.

[0013] In the imaging device of the present technology described above, it is conceivable that the signal processing unit performs pupil imbalance correction to equalize the variation in the output value due to the image height with respect to the output value of the first photodiode pixel and the output value of the second photodiode pixel. By pupil imbalance correction, correct the output value so that it has flat characteristics regardless of the image height.

[0014] In the imaging device of the present technology described above, it is conceivable that the signal processing unit performs the pupil imbalance correction on the output value of the first photodiode pixel and the output value of the second photodiode pixel after performing the saturation handling. Perform pupil imbalance correction on the output value after the overflow portion is reflected by the saturation handling.

[0015] The signal processing method according to the present technology is an imaging device including an image sensor having a photodiode-divided pixel including a first photodiode pixel and a second photodiode pixel that output respective separate pixel signals. When the output value of the pixel signal reaches the saturation value, perform saturation handling to correct the output value based on the saturation value and the output predicted value. Thereby, the output value is optimized even when saturation occurs.

Brief Description of the Drawings

[0016]

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Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments will be described in the following order with reference to the accompanying drawings. <1. Configuration of Imaging Device> <2. Overflow and Saturation Handling> <3. AF Control Processing> <4. Summary and Variations>

[0018] <1. Configuration of Imaging Device> The appearance of the imaging device 1 according to this embodiment is shown in FIGS. 1 and 2. In the following examples, the subject side is described as the front and the photographer side is described as the rear, but these directions are for convenience of explanation and are not limited to these directions for the implementation of the present technology.

[0019] As shown in FIGS. 1 and 2, the imaging device 1 includes a camera housing 2 in which various required components are arranged inside and outside, and a lens barrel 3 that is detachable from the camera housing 2 and is attached to the front surface portion 2a. Note that the lens barrel 3 being detachable as a so-called interchangeable lens is just an example, and a lens barrel that cannot be removed from the camera housing 2 may also be used.

[0020] A rear monitor 4 is arranged on the rear surface portion 2b of the camera housing 2. The rear monitor 4 displays a live view image, a playback image of a recorded image, and the like. The rear monitor 4 is, for example, a display device such as a liquid crystal display (LCD) or an organic EL (Electro-Luminescence) display. The rear monitor 4 is rotatable with respect to the camera housing 2. For example, the lower end portion of the rear monitor 4 can be rotated so as to move rearward with the upper end portion of the rear monitor 4 as a rotation axis. Note that the right end portion or the left end portion of the rear monitor 4 may be used as a rotation axis. Further, it may be rotatable in a plurality of axial rotation directions.

[0021] An EVF (Electric Viewfinder) 5 is arranged on the upper surface portion 2c of the camera body 2. The EVF 5 includes an EVF monitor 5a and a frame-shaped surrounding portion 5b that protrudes rearward so as to surround the upper, left, and right sides of the EVF monitor 5a. The EVF monitor 5a is formed using an LCD, an organic EL display, or the like. Note that an optical viewfinder (OVF: Optical View Finder) may be provided instead of the EVF monitor 5a.

[0022] Various operation elements 6 are provided on the rear surface portion 2b and the upper surface portion 2c. For example, a playback menu activation button, a determination button, a cross key, a cancel button, a zoom key, a slide key, and the like. These operation elements 6 include various forms such as buttons, dials, and composite operation elements that can be pressed and rotated. With operation elements 6 of various forms, for example, menu operations, playback operations, mode selection / switching operations, focus operations, zoom operations, and parameter selection / setting such as shutter speed and F value are possible. As one of the operation elements 6, there is a shutter button 6S (release button) for release operation. When the shutter button 6S is half-pressed, an AF operation is performed.

[0023] The internal configuration of such an imaging device 1 is shown in FIG. 3. Inside and outside the camera body 2 of the imaging device 1, an imaging element 7, a camera signal processing unit 8, a recording unit 9, a display unit 10, an output unit 11, an operation unit 12, a power supply unit 13, a camera control unit 14, a memory unit 15, a RAM 21, and the like are provided. The lens barrel 3 is configured to include an optical system 16, a driver unit 17, a lens barrel control unit 18, an operation unit 19, a memory unit 20, and the like.

[0024] The optical system 16 includes various lenses such as an incident end lens, a zoom lens, a focus lens, and a condenser lens, and a diaphragm mechanism that performs exposure control by adjusting the aperture amount by lenses or an iris (diaphragm) so that sensing is performed in a state where the signal charge is within the dynamic range without saturation, and a shutter unit such as a focal plane shutter. Note that some of the components constituting the optical system 16 may be provided in the camera body 2.

[0025] The imaging device 7 is, for example, of a CCD (Charge Coupled Device) type or a CMOS (Complementary Metal - Oxide Semiconductor) type, and performs exposure control on the light from the subject incident through the optical system 16. And it is configured to include a processing unit that performs, for example, CDS (Correlated Double Sampling) processing, AGC (Automatic Gain Control) processing, and A / D (Analog / Digital) conversion processing on the electrical signal photoelectrically converted by the pixels. Therefore, the imaging device 7 outputs an imaging image signal as digital data to the camera signal processing unit 8 and the camera control unit 14.

[0026] The sensor surface of the imaging device 7 is configured to have a sensing element in which a plurality of pixels are two - dimensionally arranged. As shown in FIG. 4, the imaging device 7 is formed by arranging PD - divided pixels 40 in a matrix in the row direction and the column direction. Each PD - divided pixel 40 is composed of two PD pixels.

[0027] The configuration of the PD - divided pixel 40 is schematically shown in FIG. 5. The PD split pixel 40 includes two PD pixels, namely, the left PD pixel 41L which is the left PD pixel and the right PD pixel 41R which is the right split pixel, a pixel boundary metal 45 disposed in front thereof, an inner lens 42, a color filter 43, and an on-chip microlens 44. The color filter 43 is any one of a color filter having a spectral sensitivity of red (R), a color filter having a spectral sensitivity of green (G), and a color filter having a spectral sensitivity of blue (B). Note that there is also a configuration example in which the inner lens 42 or the like is not provided.

[0028] As shown in the figure, the left PD pixel 41L receives light that has passed through the right pupil region EPR of the exit pupil EP. The right PD pixel 41R receives light that has passed through the left pupil region EPL. Thereby, a pupil splitting function is realized.

[0029] Such PD split pixels 40 are arranged as R pixels, G pixels, and B pixels as shown in FIG. 4 due to the difference in the color filter 43. For example, in the case of a G pixel as one PD split pixel 40, the signal obtained as the added value of the left PD pixel 41L and the right PD pixel 41R becomes the signal of one G pixel. Also, phase difference detection can be performed based on the values of the left PD pixel 41L and the right PD pixel 41R.

[0030] Returning to FIG. 3 for explanation. The camera signal processing unit 8 is constituted by, for example, a microprocessor specialized in digital signal processing such as a DSP (Digital Signal Processor), a microcomputer, or the like.

[0031] The camera signal processing unit 8 performs various signal processes on the digital signal (imaging image signal) sent from the imaging device 7. Specifically, processes such as correction processing between the R, G, and B color channels, white balance correction, aberration correction, shading correction, etc. are performed. Also, the camera signal processing unit 8 performs YC generation processing for generating (separating) a luminance (Y) signal and a color (C) signal from the R, G, and B image data, processing for adjusting luminance and color, and various processes such as knee correction and gamma correction. Furthermore, the camera signal processing unit 8 performs conversion to the final output format by performing resolution conversion processing, codec processing for encoding for recording or communication, and the like. The image data converted to the final output format is stored in the memory unit 15. In addition, when the image data is output to the display unit 10, an image is displayed on the rear monitor 4 and the EVF monitor 5a. Furthermore, when output from the external output terminal, it is displayed on a device such as a monitor provided outside the imaging device 1.

[0032] The camera signal processing unit 8 also performs phase difference detection processing. The phase difference detection processing is a process of performing phase difference detection from the output values of the left PD pixel 41L and the right PD pixel 41R of the PD divided pixel 40. The camera signal processing unit 8 also calculates a defocus amount based on the detected phase difference information. The calculated defocus amount is used for AF control in the camera control unit 14. That is, the camera control unit 14 performs drive control of the focus lens in the optical system 16 via the lens barrel control unit 18 based on the defocus amount, and executes the AF operation. Note that the calculated defocus amount may be used to present information regarding the focus condition of the subject to the user. The RAM 21 is shown as a memory that temporarily stores the output values of the left PD pixel 41L and the right PD pixel 41R and the like in the process of the phase difference detection processing.

[0033] The recording unit 9 is composed of, for example, a non-volatile memory, and stores image files (content files) such as still image data and moving image data, attribute information of the image files, thumbnail images, and the like. The image files are stored in formats such as JPEG (Joint Photographic Experts Group), TIFF (Tagged Image File Format), GIF (Graphics Interchange Format), and the like. The actual form of the recording unit 9 can be considered in various ways. For example, the recording unit 9 may be configured as a flash memory built into the imaging device 1, or it may be composed of a memory card (e.g., a portable flash memory) that can be attached to and detached from the imaging device 1 and an access unit that performs access for storage and reading on the memory card. Also, it may be realized as an HDD (Hard Disk Drive) or the like in a form built into the imaging device 1.

[0034] The display unit 10 executes processes for performing various displays for the imaging person. The display unit 10 is, for example, the rear monitor 4 or the EVF monitor 5a. The display unit 10 performs a process of displaying the image data converted to an appropriate resolution input from the camera signal processing unit 8. Thereby, a so-called through image, which is an imaging image during release standby, is displayed. Furthermore, the display unit 10 realizes displays as a GUI (Graphical User Interface), such as various operation menus, icons, messages, etc., on the screen based on instructions from the camera control unit 14. Also, the display unit 10 can display a reproduced image of the image data read from the recording medium in the recording unit 9.

[0035] The output unit 11 performs data communication and network communication with external devices by wire or wirelessly. For example, it transmits imaging image data (still image files or moving image files) to an external display device, recording device, playback device, etc. Also, the output unit 11 may function as a network communication unit. For example, it may perform communication via various networks such as the Internet, home network, and LAN (Local Area Network), and perform transmission and reception of various data with servers and terminals on the network.

[0036] The operation unit 12 provided on the camera housing 2 includes not only the various operation elements 6 described above but also the rear monitor 4 that adopts a touch panel method, etc., and outputs operation information corresponding to various operations such as tap operations and swipe operations of the imaging person to the camera control unit 14. Note that the operation unit 12 may function as a receiving unit of an external operation device such as a remote controller that is separate from the imaging device 1.

[0037] The power supply unit 13 generates a necessary power supply voltage (Vcc) for each unit from, for example, a battery filled inside, and supplies it as an operating voltage. In a state where the lens barrel 3 is attached to the imaging device 1, the power supply voltage Vcc from the power supply unit 13 is configured to be supplied also to a circuit inside the lens barrel 3. Note that a circuit for charging the battery and a circuit for generating the power supply voltage Vcc may be formed in the power supply unit 13 using, as a power supply, a DC voltage that is converted and input by an AC adapter connected to a commercial AC power supply.

[0038] The camera control unit 14 is configured by a microcomputer (arithmetic processing unit) including a CPU (Central Processing Unit), and performs overall control of the imaging device 1. For example, it controls the shutter speed according to the operation of the imaging person, gives instructions regarding various signal processes in the camera signal processing unit 8, controls the imaging operation and recording operation according to the user's operation, and controls the playback operation of the recorded image file.

[0039] In addition, the camera control unit 14 gives an instruction to the lens barrel control unit 18 in order to control various lenses included in the optical system 16. For example, it gives instructions such as zoom control and AF control. Further, the camera control unit 14 performs a process of specifying an aperture value in order to secure a necessary amount of light for AF control, and gives an operation instruction to the aperture mechanism according to the aperture value.

[0040] The camera control unit 14 can acquire various lens information included in the optical system 16 via the lens barrel control unit 18. The lens information includes, for example, information such as the lens model number, the position of the zoom lens, the F value, or the information of the exit pupil position. In addition, the camera control unit 14 can acquire the aperture value of the aperture mechanism included in the optical system 16.

[0041] The memory unit 15 stores information and the like used in the processes executed by the camera control unit 14. As the illustrated memory unit 15, for example, ROM (Read Only Memory), RAM (Random Access Memory), flash memory, etc. are comprehensively shown. Note that the memory unit 15 and the above-described RAM 21 may be memory areas built into a microcomputer chip serving as the camera control unit 14, or may be configured by separate memory chips.

[0042] Programs and the like used by the camera control unit 14 are stored in the ROM, flash memory, etc. of the memory unit 15. In the ROM, flash memory, etc., in addition to the OS (Operating System) for the CPU to control each unit and content files such as image files, application programs and firmware for various operations are stored. By executing the program, the camera control unit 14 controls the entire imaging device 1 and the lens barrel 3.

[0043] The RAM of the memory unit 15 is used as a working area for the camera control unit 14 by temporarily storing data, programs, etc. used in various data processes executed by the CPU of the camera control unit 14.

[0044] The lens barrel control unit 18 of the lens barrel 3 is constituted by, for example, a microcomputer, and outputs a control signal to the driver unit 17 to actually drive various lenses of the optical system 16 based on an instruction from the camera control unit 14. Note that information communication between the camera control unit 14 and the lens barrel control unit 18 may be possible only when the lens barrel 3 is attached to the camera housing 2, or may be possible by wireless communication when the lens barrel 3 is not attached to the camera housing 2.

[0045] The lens barrel control unit 18 transmits information on the exit pupil position and the pupil distance of the exit pupil to the camera control unit 14 based on the types and driving positions of various lenses included in the optical system 16. Specifically, information regarding the pupil distance is acquired from the information stored in the ROM as the memory unit 20 and transmitted to the camera control unit 14.

[0046] The driver unit 17 is provided with, for example, a motor driver for the zoom lens driving motor, a motor driver for the focus lens driving motor, a diaphragm mechanism driver for the motor that drives the diaphragm mechanism, and the like. Each driver supplies a drive current to the corresponding drive motor in response to an instruction from the lens barrel control unit 18.

[0047] The operation unit 19 of the lens barrel 3 indicates an operator provided on the lens barrel 3 side. The operation information by the operation unit 19 is supplied to the lens barrel control unit 18 and notified to the camera control unit 14 via the lens barrel control unit 18. In response to the operation of the operation unit 19, the lens barrel control unit 18 controls the operation of the optical system 16, and the camera control unit 14 performs various settings and operation controls.

[0048] The operation unit 19 may function as a reception unit of an external operation device such as a remote controller separate from the lens barrel 3.

[0049] The memory unit 20 is composed of a ROM, a flash memory, etc., and stores programs, data, etc. used by the lens barrel control unit 18. The memory unit 20 stores an OS (Operating System) for the CPU to control each unit, application programs for various operations, firmware, and the like. In addition, the information stored in the memory unit 20 includes information such as the pupil distance of the exit pupil of the optical system 16.

[0050] FIG. 6 shows a configuration related to the phase difference detection process in the camera signal processing unit 8 and a configuration related to the AF control based thereon. As shown in FIG. 6, the camera signal processing unit 8 includes a difference operation unit 51, a saturation countermeasure processing unit 52, a pupil imbalance correction unit 53, and a correlation operation unit 54 as a configuration related to phase difference detection processing.

[0051] The output value of the PD divided pixel 40 from the image sensor 7 is supplied to the difference operation unit 51. In the case of the image sensor 7 in which the PD divided pixel 40 having the left PD pixel 41L and the right PD pixel 41R is arranged as shown in FIG. 4 above, each PD divided pixel 40 can not only read out a normal pixel signal for image generation, but also obtain the output values of the left and right PDs separately. The defocus amount for AF control can be calculated from the output values of the left and right PDs. For this purpose, for one PD divided pixel 40, for example, the (L + R) value and the L value are read out. Note that the “(L + R) value” refers to the output value obtained by adding the charges from the left PD pixel 41L and the right PD pixel 41R. The “L value” is the output value obtained by reading the charge from the left PD pixel 41L.

[0052] The (L + R) value, that is, the added value of the read charges from the left PD pixel 41L and the right PD pixel 41R, has the meaning as the pixel value of the PD divided pixel 40, and thus becomes a signal used for image generation. Also, when the L value is read out to obtain the output value (L value) of the left PD pixel 41L, the output value (R value) of the right PD pixel 41R can be obtained by (L + R) value - L value. The phase difference of the pixel components divided by the pupil can be obtained from this “L value” and “R value”. The difference operation unit 51 in FIG. 6 performs such an operation of (L + R) value - L value to obtain the output value (R value) of the right PD pixel 41R. The L value is supplied to the difference operation unit 51 and also supplied to the saturation countermeasure processing unit 52. Note that in the embodiment, the example of reading the (L + R) value and the L value as described above will be described. However, by reading the (L + R) value and the R value, the L value and the R value can be obtained in the same concept.

[0053] When an overflow occurs in the left PD pixel 41L or the right PD pixel 41R, the saturation handling unit 52 performs processing to correct the L value and the R value to their original values accordingly. This can be said to be processing for restoring the output values when it is assumed that the output ranges of the L value and the R value are wider in the direction of a higher overflow level. Therefore, while temporarily storing the L value and the R value in the RAM 21, the saturation handling unit 52 performs necessary calculation processing to obtain the corrected L value and R value.

[0054] However, whether to execute the saturation handling is instructed to the saturation handling unit 52 by the control signal SON from the camera control unit 14. When the execution is instructed by the control signal SON, the saturation handling unit 52 performs the saturation handling. When no execution instruction is given by the control signal SON, the saturation handling unit 52 transfers the input L value and R value as they are to the pupil imbalance correction unit 53.

[0055] The pupil imbalance correction unit 53 performs correction (left and right PD pixel pupil imbalance correction) to make the fluctuations in the output values that occur according to the image height flat regardless of the image height and to match the output levels of the L value and the R value for the L value and the R value. For this left and right PD pixel pupil imbalance correction, the vignetting information stored in the memory unit 15 and the light reception angle characteristics of the left PD pixel 41L and the right PD pixel 41R are used. Details of the saturation handling and the left and right PD pixel pupil imbalance correction will be described later.

[0056] The correlation calculation unit 54 performs a correlation calculation on the L value and the R value input from the pupil imbalance correction unit 53, that is, on the signals having a phase difference. The phase difference detection by this correlation calculation will be described below. FIG. 7 shows an output waveform obtained by arranging the output values of the PD divided pixels 40 on the imaging element 7. The signal waveform (left PD pixel output 60L) by the L value output from the left PD pixel 41L is shown by a solid line, and the signal waveform (right PD pixel output 60R) by the R value output from the right PD pixel 41R is shown by a broken line.

[0057] Next, in FIG. 8A, a waveform 60L1 is shown, which is obtained by shifting the waveform of the left PD pixel output 60L to the right direction by a certain distance on the graph. Also, in FIG. 8B, a waveform 60L2 is shown, which is obtained by further shifting the waveform 60L1 to the right direction by a certain distance. Also, in FIG. 8C, a waveform 60L3 is shown, which is obtained by further shifting the waveform 60L2 to the right direction by a certain distance. In FIGS. 8A, 8B, and 8C, the absolute value of the differential integral value between the waveform of the left PD pixel output 60L and the waveform of the right PD pixel output 60R is shown as the hatched portion.

[0058] FIG. 9 shows a graph of the differential integral values indicated by the hatched portions in FIG. 7 and FIGS. 8A, 8B, and 8C. As shown in the figure, the differential integral value becomes smaller as the shift amount increases. When the shift amount exceeds a predetermined value, the differential integral value becomes larger again as the shift amount increases. The shift amount at which the differential integral value becomes the smallest is the phase difference amount. That is, appropriate AF control can be performed by moving the focus lens so that the outputs of the left PD pixel 41L and the right PD pixel 41R are phase-differentially shifted and the waveforms of the left PD pixel output 60L and the right PD pixel output 60R substantially overlap.

[0059] Note that the so-called front pin and rear pin can be distinguished depending on the direction in which the waveform of the left PD pixel output 60L is shifted. That is, in the state of FIG. 9, the differential integral value can be minimized by shifting the waveform of the left PD pixel output 60L to the right direction. This state is the so-called front pin state. On the other hand, when the differential integral value can be minimized by shifting the waveform of the left PD pixel output 60L to the left direction, it is the so-called rear pin state.

[0060] Fig. 10 shows the relationship between the shift amount and the defocus amount. The shift amount refers to the shift amount when the differential integral value shown in Fig. 7 becomes smaller, and can be regarded as the phase difference. When the defocus amount is near zero, the relationship between the shift amount and the defocus amount can be generally expressed by a linear function. The larger the shift amount, the larger the defocus amount, and a large shift amount means that the focus is not in place. The defocus amount DF can be calculated from the shift amount.

[0061] The correlation operation unit 54 obtains this defocus amount DF and outputs it to the camera control unit 14. The camera control unit 14 can perform AF control using the defocus amount DF.

[0062] <2. Overflow and saturation handling> Hereinafter, the overflow that occurs in the PD divided pixel 40 and the saturation handling for it will be described. First, Fig. 11 schematically shows the state of overflow of the single-sided PD. When the incident light is from medium luminance to high luminance, overflow may occur in one of the PD pixels of the PD divided pixel 40, and the output value may become the saturation value.

[0063] For example, in the PD divided pixel 40 at the peripheral part of the imaging device 7, the incident light enters obliquely. In the example of Fig. 11, it is easy to enter the left PD pixel 41L. Therefore, overflow is likely to occur on the left PD pixel 41L side.

[0064] Here, it was stated that the (L + R) value from the PD divided pixel 40 is also used as a pixel signal for image generation. That is, one pixel constituting the image is formed by a pair of the left PD pixel 41L and the right PD pixel 41R. Therefore, when overflow occurs in one of the PD pixels, it is not desirable to discard the excess charge. This is because the accuracy of the luminance value of the pixel deteriorates. Therefore, in the PD split pixel 40, when an overflow occurs in one PD pixel, the pixel circuit configuration is such that the surplus charge leaks into the other PD pixel. FIG. 11 shows the state of leakage from the left PD pixel 41L to the right PD pixel 41R.

[0065] That is, in the PD split pixel 40, when an overflow occurs in the left PD pixel 41L, charge leakage to the right PD pixel 41R occurs, and when an overflow occurs in the right PD pixel 41R, charge leakage to the left PD pixel 41L occurs. In this way, an output value ((L + R) value) corresponding to the amount of received light is obtained for the entire PD split pixel 40. As a result, the accuracy of the pixel signal for forming an image is maintained, but it becomes inconvenient for the phase difference detection for the purpose of the above-described AF control or the like. For example, when leakage occurs as shown in FIG. 11, the L value is clipped at the saturation value and becomes a value smaller than the original output value, and the R value becomes a value larger than the original output value due to the leakage. This reduces the detection accuracy of the defocus amount DF based on the differential integration value of the waveforms of the L value and the R value. That is, it reduces the AF accuracy.

[0066] For example, FIG. 12A shows the L value and the R value with the horizontal axis being the H image height (image height in the horizontal direction) and the vertical axis being the output value. In this case, the horizontal axis can be considered as the horizontal direction of the imaging device 7. For example, it is the output value corresponding to the pixel position when an all-white subject is incident on all the pixels of the imaging device 7. The one-dot chain line indicates the overflow level. The solid line and the broken line show the output value (L value) of the left PD pixel 41L and the output value (R value) of the right PD pixel 41R in a state where overflows are not considered.

[0067] Considering overflows and leakages as described above, the actual L value and R value are as shown in FIG. 12B. That is, the output value is clipped for pixels exceeding the overflow level, and the value of the other PD pixel increases due to the leakage. As a result, the accuracy of the phase difference detection between the L value and the R value decreases, leading to a decrease in the detection accuracy of the defocus amount DF.

[0068] Also, overflow and left-right PD pixel pupil imbalance correction will be described. The left-right PD pixel pupil imbalance correction corrects the level difference caused by the incident light angle according to the H image height, and by using a correction coefficient according to the horizontal pixel address (the coordinate value in the horizontal line direction of the pixels in the imaging device 7), as shown in FIG. 12C, the horizontal level characteristics of the L value and the R value are made flat. As a result, the level difference according to the pixel positions of the L value and the R value can be eliminated, and the AF accuracy can be improved. However, this is the case where the left-right PD pixel pupil imbalance correction is performed on the L value and the R value in the ideal state of FIG. 12A without overflow.

[0069] However, considering overflow and leakage, the actual L value and R value are as shown in FIG. 12B. If the left-right PD pixel pupil imbalance correction is performed in this state, overcorrection will be applied to the pixels where overflow has occurred, and the corrected L value and R value will be as shown in FIG. 12D. Such overcorrection causes the waveform to collapse and conversely decreases the AF accuracy.

[0070] Therefore, in the present embodiment, as saturation countermeasure processing, the original values as the L value and the R value are restored. FIG. 13 shows the L value and the R value with the horizontal axis being the H image height and the vertical axis being the output value, similar to FIG. 12A. The dashed-dotted line indicates the overflow level, and the solid line and the broken line indicate the output value (L value) of the left PD pixel 41L and the output value (R value) of the right PD pixel 41R in a state where overflow is not considered.

[0071] Since the actual output value is clipped at the overflow level, considering the actual L value and R value of the PD divided pixel 40 of a certain pixel address [i] in the horizontal direction, the L value (L_PD[i]) becomes the overflow level. Also, the R value (R_PD[i]) becomes a level that is higher by the leakage amount x than the actual level due to the influence of the leakage of the overflow. Note that the leakage amount x can also be said to be the amount of charge cut off due to overflow on the left PD pixel 41L side.

[0072] In this Figure 13, the L value and R value shown by the solid line and the broken line are ideal values assuming no overflow occurs, so the values of the portions exceeding the overflow level cannot actually be obtained. Therefore, such ideal values can be obtained as the output predicted values (L_PD_Pre[i]) and (R_PD_Pre[i]) of the L value and R value. That is, they are the output predicted values of each PD pixel corresponding to the pixel address [i]. If such output predicted values are obtained, using the output predicted values and the actual output values, the original output values, that is, the L value and R value that would have been obtained if no overflow had occurred, can be obtained.

[0073] The output predicted values can be obtained based on the light reception angle characteristics of the PD pixels and the information on vignetting. First, the light reception angle characteristics of the right PD pixel 41R and the left PD pixel 41L will be explained with reference to Figure 14. Figure 14A shows the light reception angle characteristics of the right PD pixel 41R and the left PD pixel 41L, and shows the distribution of the light reception sensitivity on the pan axis (pan angle) and tilt axis (tilt angle) by contour lines. The light reception sensitivity is higher towards the center side of the contour lines. Figure 14B shows the light reception angle characteristics of the right PD pixel 41R and the left PD pixel 41L in a cross-section at a tilt axis of 0°, with the horizontal axis being the pan axis and the vertical axis being the sensitivity. Figure 14C shows the light reception images of the right PD pixel 41R and the left PD pixel 41L.

[0074] As can be seen from FIG. 14, the right PD pixel 41R has high sensitivity to light rays from the right direction, and the left PD pixel 41L has high sensitivity to light rays from the left direction.

[0075] In order to predict the output for the right PD pixel 41R and the left PD pixel 41L with such sensitivity characteristics, it is necessary to consider the lens aperture cut (the angle range through which light passes).

[0076] FIG. 15A shows the lens aperture cut 90 on the contour line of the light reception angle characteristics for the PD divided pixel 40 that is at the center in the H direction (horizontal direction) and at the center in the V direction (vertical direction) in the image sensor 7. The horizontal axis is the pan axis angle, and the vertical axis is the tilt angle. The integrated value of the light reception sensitivity within the lens aperture cut 90 becomes the output value of the PD pixel. In the case of this pixel, the output value (R value) of the right PD pixel 41R and the output value (L value) of the left PD pixel 41L are equal.

[0077] FIG. 15B shows the lens aperture cut 90 on the contour line of the light reception angle characteristics for the PD divided pixel 40 that is at the + side end in the H direction and at the center in the V direction in the image sensor 7. From the integrated value of the light reception sensitivity within the lens aperture cut 90, R value > L value. FIG. 15C shows the lens aperture cut 90 on the contour line of the light reception angle characteristics for the PD divided pixel 40 that is at the + side end in the H direction and at the + side end in the V direction in the image sensor 7. From the integrated value of the light reception sensitivity within the lens aperture cut 90, R value > L value.

[0078] That is, by having the information of the lens aperture cut 90 and the light reception angle characteristics for, for example, the positions of all the pixels in the image sensor 7, the output prediction value can be obtained with the integrated value of the light reception sensitivity within the lens aperture cut 90. For example, since the light reception angle characteristics are the characteristics of the mounted image sensor 7, they are fixed and can be stored in, for example, the memory unit 15. Thereby, the camera control unit 14 can provide the information of the light reception angle characteristics to the saturation countermeasure processing unit 52. The information on the 90% vignetting of the lens aperture depends on the lens barrel 3, the F-number, etc. Therefore, the camera control unit 14 can obtain the information on the 90% vignetting of the lens aperture in real time through communication with the lens barrel control unit 18 and provide it to the saturation countermeasure processing unit 52. Alternatively, the camera control unit 14 may calculate an output prediction value from the light reception angle characteristics of the imaging element 7 and the information on the 90% vignetting of the lens aperture and provide the output prediction value to the saturation countermeasure processing unit 52. In any case, the saturation countermeasure processing unit 52 can obtain an output prediction value from the light reception angle characteristics of the imaging element 7 and the information on the 90% vignetting of the lens aperture.

[0079] Therefore, the saturation countermeasure processing unit 52 performs saturation countermeasure processing as specifically shown in FIG. 16. In step S1, the saturation countermeasure processing unit 52 detects an overflow. By detecting the overflowed PD divided pixel 40, it can be determined that saturation countermeasure processing is required for the PD divided pixel 40. Specifically, when the output value as the L value or R value reaches the overflow level, it can be determined that an overflow has occurred. For example, when the output value is 12 bits and reaches the maximum value such as "FFF" in hexadecimal notation, it can be determined as an overflow.

[0080] As described with reference to FIG. 13, if the L value of the pixel address [i] is L_PD[i] and the R value is R_PD[i], then if L_PD[i] = 0xFFF or R_PD[i] = 0xFFF (where 0x indicates hexadecimal notation), that pixel can be determined as a pixel where an overflow has occurred. Note that the overflow level is not necessarily limited to the maximum value such as "0xFFF". There may also be a design where an overflow is considered even if the voltage value is less than "0xFFF". In that case, the overflow determination is performed based on the set overflow value.

[0081] In step S2 of FIG. 16, the saturation correspondence processing unit 52 holds (temporarily stores for calculation) the output value of the PD pixel that is not overflowing as a calculation value to be used in the subsequent step S4. For example, if the L value has overflowed, the saturation correspondence processing unit 52 sets the L_PD[i] value to the overflow level "0xFFF", but holds the output value (R value) of the right PD pixel 41R that has not overflowed as R_PD[i] for calculation.

[0082] In step S3, the saturation correspondence processing unit 52 holds the output prediction values of the left PD pixel 41L and the right PD pixel 41R for the overflowed PD divided pixel 40 as calculation values to be used in the subsequent step S4. Output prediction value of right PD pixel 41R = R_PD_Pre[i] Output prediction value of left PD pixel 41L = L_PD_Pre[i] Let it be so.

[0083] In step S4, the saturation correspondence processing unit 52 obtains the leakage amount x. In this case, (L_PD[i] + x) / (R_PD[i] - x) = L_PD_Pre[i] / R_PD_Pre[i] Based on this equation, the leakage amount x is obtained. This is based on the assumption that the leakage amount x is in the ratio of the output prediction values.

[0084] Once the leakage amount x is obtained, in step S5, the saturation correspondence processing unit 52 corrects the L value and the R value. The leakage amount x can be said to be the difference value between the output prediction value and the saturation value (overflow level) for the PD pixel on which overflow has occurred. Therefore, when the corrected L value is L_PD_New[i] and the R value is R_PD_New[i], L_PD_New[i] = L_PD[i] + x R_PD_New[i] = R_PD[i] - x Let it be so.

[0085] The above processing becomes saturation countermeasure processing, and when no overflow occurs due to this, the original L value and R value are obtained. Regarding such corrected L values and R values, when left-right PD pixel pupil imbalance correction is performed, as shown in FIG. 12 C appropriate correction can be performed as shown in FIG. 12, and a decrease in AF accuracy can be prevented.

[0086] <3. AF Control Processing> The AF control processing will be described with reference to FIG. 17. In step S101 of FIG. 17, the camera control unit 14 monitors the half-press of the shutter button 6S. When the half-press is not performed, other processes (not shown) are performed. If the half-press is performed, the processing in FIG. 17 proceeds to step S102 and subsequent steps.

[0087] Specifically, the camera control unit 14 instructs the camera signal processing unit 8 to calculate the defocus amount DF. However, at this time, it does not instruct the execution of saturation countermeasure processing by the control signal SON. Therefore, the camera signal processing unit 8 obtains the defocus amount without performing saturation countermeasure processing. The camera signal processing unit 8 reads the PD divided pixels 40 in step S102, performs left-right PD pixel pupil imbalance correction in step S103, and performs a correlation operation in step S104. The defocus amount DF obtained thereby is supplied to the camera control unit 14.

[0088] In step S105, the camera control unit 14 determines whether the defocus amount DF is approximately zero, that is, whether it is in a state close to focus. For example, it determines whether the defocus amount DF is within a certain range near zero (a value that can be said to be approximately in focus). Alternatively, in step S105, it may be determined whether the defocus amount DF = 0.

[0089] If the defocus amount DF ≒ 0 is not satisfied, the camera control unit 14 determines the defocus amount DF in step S106, controls the driving of the focus lens according to the defocus amount DF in step S107, and then returns to step S102. Therefore, the defocus amount DF is obtained by the camera signal processing unit 8 at the following timing, and the camera control unit 14 determines whether the defocus amount DF≈0 in step S105.

[0090] The above is normal AF control, in which the focus lens drive is executed while sequentially obtaining the defocus amount DF, and the focus lens is controlled to move to the lens position where the defocus amount DF = 0.

[0091] As a result, the focus lens is controlled to move to the in-focus state, and at a certain point in time, it is determined in step S105 that the defocus amount DF≈0 (or DF = 0). In this case, the camera control unit 14 proceeds to step S110 and branches the process depending on whether an overflow has occurred during the AF control up to this point. If no overflow has occurred, the accuracy of the defocus amount DF has not decreased in the control up to this point. Therefore, the focus lens should have moved to the in-focus position. Thus, it proceeds to step S116 and stops the lens movement as the in-focus position. This is suitable when the defocus amount DF≈0 is set as an acceptable range for the in-focus state. When proceeding to step S105 with DF≈0 instead of DF = 0 and no overflow has occurred, as shown by the dashed line from step S110, it proceeds to steps S114 and S115, and after performing the last focus lens movement with the defocus amount DF, the lens movement may be stopped as the in-focus position. Note that the value defining the range for DF≈0 is stored in advance as a parameter by the camera control unit 14.

[0092] On the other hand, if an overflow has occurred during the AF control process leading to the defocus amount DF≈0 (or DF = 0), the accuracy of the defocus amount DF may have decreased. Therefore, after step S111, the camera signal processing unit 8 instructs the camera signal processing unit 8 to calculate the defocus amount DF. At this time, it instructs the execution of saturation countermeasure processing by the control signal SON.

[0093] Therefore, the camera signal processing unit 8 will obtain the defocus amount DF after performing the saturation countermeasure processing. The camera signal processing unit 8 performs saturation countermeasure processing on the L value and R value read in step S102 immediately before at step S111, performs left and right PD pixel pupil imbalance correction again at step S112, and performs correlation calculation again at step S113 to obtain the defocus amount DF.

[0094] The camera control unit 14 determines the defocus amount DF at step S114, controls the driving of the focus lens according to the defocus amount at step S115, and stops the lens movement at step S116.

[0095] In the above processing, first, AF control is performed without performing saturation countermeasure processing, and the focus state is pursued to a certain extent. Then, as a result of the correlation calculation, if the result of the defocus amount DF≒0 is obtained and there are overflow pixels, the saturation countermeasure processing is performed and then the correlation calculation is performed again to move the focus lens as a fine adjustment.

[0096] The saturation countermeasure processing can be said to be a process of dividing back the charge amount (leakage amount x) leaked from one overflowed PD pixel to the other PD pixel by the output value on the overflowed side. That is, it is premised on the fact that the leakage amount x was originally to be added to the output value on the overflowed side.

[0097] Considering the correlation calculation described with reference to FIGS. 7 and 8 here, when the focus has not been achieved, the left PD pixel output 60L which is the waveform of the L value and the right PD pixel output 60R which is the waveform of the R value have shifted waveforms, and as the focus state is approached, the waveforms overlap. And the fact that the waveforms are shifted means that different subject lights are received by the right PD pixel 41R and the left PD pixel 41L in one PD-divided pixel 40, and the fact that the waveforms overlap means that the right PD pixel 41R and the left PD pixel 41L are receiving the same subject light.

[0098] That is, when out of focus and the phases of the left PD pixel output 60L and the right PD pixel output 60R are shifted, it is not known whether the leakage amount x affects the difference between the L value and the R value or whether the difference in the subject affects it. In other words, the leakage amount x cannot be accurately calculated. Therefore, it can be said that the saturation countermeasure process functions properly when in focus or near the in-focus state. Therefore, in the process of FIG. 17, until approaching the in-focus state, AF control is performed without performing the saturation countermeasure process. When almost in focus and an overflow has occurred, after performing the saturation countermeasure process, the defocus amount DF is obtained again and AF control is performed to perform fine adjustment.

[0099] <4. Summary and Variations> The following effects can be obtained in the above embodiments. The imaging device 1 of the embodiment includes an imaging element 7 having a PD-divided pixel 40 including a left PD pixel 41L (first PD pixel) and a right PD pixel 41R (second PD pixel) that output different pixel signals. Further, when the output value of the pixel signal reaches the saturation value (overflow level), it includes a camera signal processing unit 8 that performs a saturation countermeasure process for correcting the output value based on the saturation value and the output prediction value. Thereby, the output values of the left PD pixel 41L and the right PD pixel 41R in the PD-divided pixel 40 are optimized, and by improving the accuracy of the defocus amount DF, the AF performance can be improved. In the saturation countermeasure process of the embodiment, both the overflowed output value and the output value with the leakage amount x added are corrected, but only one of them may be used. For example, a saturation countermeasure process can also be considered in which only the output value that has reached the clip level is corrected to the original value, or only the output value with leakage is corrected to a state without leakage.

[0100] The saturation handling process described in the embodiments includes a process of calculating a difference value between the output prediction value and the saturation value. Based on the difference between the output prediction value and the saturation value, the level fluctuated by overflow can be estimated. By correcting the output value (L value, R value) based on this, the original output value when no overflow occurred can be restored.

[0101] In the saturation handling process of the embodiments, for one of the PD pixels among the left PD pixel 41L and the right PD pixel 41R, a difference value between the output prediction value and the saturation value is calculated. When dealing with unilateral overflow for the left PD pixel 41L and the right PD pixel 41R in the PD divided pixel 40, it is only necessary to obtain the difference between the output prediction value and the saturation value for one of the PD pixels. By correcting the output value based on this, the original output value when no overflow occurred can be restored as the output value of the PD pixel on the side where overflow occurred.

[0102] In the saturation handling process of the embodiments, it is assumed that a process is performed in which the difference value calculated for one PD pixel is added to the output value of one PD pixel and subtracted from the output value of the other PD pixel. Depending on the unilateral overflow for the left PD pixel 41L and the right PD pixel 41R in the PD divided pixel 40, the charge that overflowed in one PD pixel leaks into the other PD pixel. With this structure, the output value of the entire PD divided pixel 40 can be accurately maintained. In this case, for each PD pixel, it is possible to correct the output value so as to cancel out the leakage by adding the difference value to the overflowed side and subtracting the difference value from the other side. As a result, the output values of the left PD pixel 41L and the right PD pixel 41R can be optimized, thereby improving the AF operation accuracy.

[0103] The imaging device 1 of the embodiments includes a camera control unit 14 that determines a focus state and causes the camera signal processing unit 8 to execute saturation handling processing according to the focus state. That is, in AF control, for example, when almost in focus, saturation countermeasure processing is performed (see FIG. 16). In the PD divided pixel 40, if the left PD pixel 41L and the right PD pixel 41R are in a state where light from the same subject is incident, the charge leaked from one PD pixel to the other PD pixel constitutes an image of the same subject. Therefore, there is no problem in performing saturation countermeasure processing (addition to one output value and subtraction from the other output value for the leakage amount x). However, when light from different subjects is incident on the left PD pixel 41L and the right PD pixel 41R, since they are charges for different subject lights in the first place, it is not suitable for performing saturation countermeasure processing. Therefore, saturation countermeasure processing is performed in the vicinity of the in-focus state where the left PD pixel 41L and the right PD pixel 41R receive the same subject light. Thereby, the effect of the saturation countermeasure processing can be appropriately exerted.

[0104] In the embodiment, the camera control unit 14 performs AF control based on the defocus amount DF obtained using the L value and the R value in a state where the camera signal processing unit 8 is not made to execute saturation countermeasure processing. After the condition of the in-focus state (DF≈0) is satisfied, AF control is performed based on the defocus amount DF obtained using the L value and the R value in a state where the camera signal processing unit 8 is made to execute saturation countermeasure processing (see FIG. 16). By performing AF control based on the defocus amount obtained without performing saturation countermeasure processing, the in-focus state is approached. In that state, the left PD pixel 41L and the right PD pixel 41R are in a state where light from the same subject is incident. By saturation countermeasure processing, the leakage amount can be correctly obtained and the output value can be corrected, so that AF control as fine adjustment becomes possible. Thereby, the AF accuracy can be significantly improved.

[0105] In the embodiment, it is assumed that the output prediction value is a value obtained based on the light reception angle characteristics of the left PD pixel 41L and the right PD pixel 41R and lens information. By using this output predicted value, it is possible to easily obtain the difference value from the saturation value at the time of overflow for each pixel. Since the light reception angle characteristics are known, they may be stored in the memory unit 15, and the vignetting information corresponding to the type of lens may also be stored. As a result, an appropriate output predicted value can be obtained and saturation countermeasure processing can be executed.

[0106] The imaging device 1 of the embodiment is an imaging device capable of mounting an interchangeable lens barrel 3, and the lens information is received from the lens barrel 3. As a result, even in the case of an interchangeable lens, an appropriate output predicted value corresponding to the lens barrel 3 can be used. Although an example of the lens interchangeable imaging device 1 has been described, the technology described in the embodiment is also applicable to an integrally formed lens imaging device. In that case, since the camera control unit 14 can grasp the information on the vignetting 90 of the lens aperture and the F value, etc., an output predicted value may be obtained based on them.

[0107] The camera signal processing unit 8 of the embodiment has described an example of performing pupil imbalance correction for equalizing the variation in the output value due to the image height with respect to the output values of the left PD pixel 41L and the right PD pixel 41R. In the AF control using the output values of the left PD pixel 41L and the right PD pixel 41R, by performing pupil imbalance correction, the influence of the H image height can be eliminated.

[0108] The camera signal processing unit 8 of the embodiment performs the pupil imbalance correction on the output values of the left PD pixel 41L and the right PD pixel 41R after performing the saturation countermeasure processing. As a result, it is possible to prevent overcorrection due to pupil imbalance correction in a state where the overflow components of the output values of the left PD pixel 41L and the right PD pixel 41R are reduced or added due to smear, and the signal accuracy can be improved.

[0109] Note that the effects described in this specification are merely examples and are not limited, and there may be other effects.

[0110] This technology can also adopt the following configuration. (1) An imaging device including a photodiode-divided pixel including a first photodiode pixel and a second photodiode pixel that output different pixel signals respectively, and a signal processing unit that performs saturation handling to correct the output value based on the saturation value and the output prediction value when the output value of the pixel signal reaches the saturation value. An imaging apparatus. (2) The saturation handling includes a process of calculating a difference value between the output prediction value and the saturation value. The imaging device according to (1) above. (3) In the saturation handling, for one of the first photodiode pixel and the second photodiode pixel, the difference value between the output prediction value and the saturation value is calculated. The imaging device according to (1) or (2) above. (4) In the saturation handling, the calculated difference value for the one photodiode pixel is added to the output value of the one photodiode pixel, and the difference value is subtracted from the output value of the other photodiode pixel. The imaging device according to (3) above. (5) An imaging device including a control unit that determines a focus state and causes the signal processing unit to execute the saturation handling according to the focus state. The imaging device according to any one of (1) to (4) above. (6) The control unit performs autofocus control based on the defocus amount obtained using the output value of the first photodiode pixel and the output value of the second photodiode pixel in a state where the signal processing unit does not execute the saturation handling, and then After the conditions for the focused state are satisfied, autofocus control is performed based on the defocus amount obtained using the output value of the first photodiode pixel and the output value of the second photodiode pixel in a state where the signal processing unit executes the saturation countermeasure process. The imaging device according to (5) above. (7) The output prediction value is a value obtained based on the light reception angle characteristics of the first photodiode pixel and the second photodiode pixel and lens information. The imaging device according to any one of (1) to (6) above. (8) An imaging device capable of mounting an interchangeable lens barrel, The lens information is received from the lens barrel. The imaging device according to (7) above. (9) The signal processing unit, Performs pupil imbalance correction to equalize the variation in the output value due to the image height with respect to the output value of the first photodiode pixel and the output value of the second photodiode pixel. The imaging device according to any one of (1) to (8) above. (10) The signal processing unit, Performs the pupil imbalance correction on the output value of the first photodiode pixel and the output value of the second photodiode pixel after the saturation countermeasure process is performed. The imaging device according to (9) above. (11) An imaging device including an imaging element having a photodiode divided pixel including a first photodiode pixel and a second photodiode pixel that output different pixel signals respectively, When the output value of the pixel signal becomes a saturation value, a saturation countermeasure process is performed to correct the output value based on the saturation value and the output prediction value. Signal processing method.

Explanation of symbols

[0111] 1 Imaging device 2 Camera housing 3 - lens barrel 6S - shutter button 7 - imaging device 8 - camera signal processing unit 14 - camera control unit 40 - PD divided pixels 41L - left PD pixel 41R - right PD pixel

Claims

1. An imaging device including a photodiode divided pixel including a first photodiode pixel and a second photodiode pixel that output different pixel signals respectively, a signal processing unit that performs saturation handling to correct an output value based on the saturation value and an output prediction value when the output value of the pixel signal reaches the saturation value, and a control unit that determines a focus state and causes the signal processing unit to execute the saturation handling according to the focus state. The control unit performs autofocus control based on a defocus amount obtained using the output value of the first photodiode pixel and the output value of the second photodiode pixel in a state where the signal processing unit does not execute the saturation handling, and then performs autofocus control based on a defocus amount obtained using the output value of the first photodiode pixel and the output value of the second photodiode pixel in a state where the signal processing unit executes the saturation handling after the condition of the focused state is satisfied. An imaging device.

2. The output prediction value is obtained based on the light reception angle characteristics of the photodiode divided pixel and information on vignetting, and the saturation handling includes a process of calculating a difference value between the output prediction value and the saturation value. The imaging device according to Claim 1.

3. The output prediction value is obtained based on the light reception angle characteristics of the photodiode divided pixel and information on vignetting, and in the saturation handling, a difference value between the output prediction value and the saturation value is calculated for one of the first photodiode pixel and the second photodiode pixel. The imaging device according to Claim 1.

4. In the saturation handling, the difference value calculated for the one photodiode pixel is added to the output value of the one photodiode pixel, and the difference value is subtracted from the output value of the other photodiode pixel. The imaging device according to Claim 3.

5. An imaging device capable of mounting an interchangeable lens barrel, wherein the information on vignetting is received from the lens barrel. The imaging device according to any one of Claims 2 to 4.

6. The signal processing unit performs pupil imbalance correction to equalize fluctuations in the output value due to image height for the output value of the first photodiode pixel and the output value of the second photodiode pixel. The imaging device according to any one of claims 1 to 5.

7. The signal processing unit performs the pupil imbalance correction on the output values of the first photodiode pixel and the output values of the second photodiode pixel after performing the saturation corresponding process. The imaging device according to claim 6.

8. An imaging device including an image sensor including a photodiode divided pixel including a first photodiode pixel and a second photodiode pixel that output different pixel signals respectively is a signal processing method for performing a saturation corresponding process of correcting an output value based on the saturation value and an output prediction value when the output value of the pixel signal becomes a saturation value, after performing autofocus control based on a defocus amount obtained using the output value of the first photodiode pixel and the output value of the second photodiode pixel in a state where the saturation corresponding process is not executed, determines a focused state, and after the conditions for the focused state are satisfied, performs autofocus control based on a defocus amount obtained using the output value of the first photodiode pixel and the output value of the second photodiode pixel in a state where the saturation corresponding process is executed. Signal processing method.

Images