JP2016031446A - Imaging device and method of controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, by an imaging element, arithmetic processing for a focus detection signal that can suppress a decrease in focus detection precision even when a focus detection pixel has low distribution density.SOLUTION: An imaging element has a focus detection pixel and an imaging pixel which receive light made incident through a microlens, respectively. An arithmetic control unit 105 acquires pixel signals output from the focus detection pixel and the imaging pixel through first exposure, respectively, and also acquires pixel signals output from the focus detection pixel and the imaging pixel through second exposure, in which a focus position is moved by a predetermined distance by driving a focus adjustment lens, respectively. When a photoelectric conversion unit of an imaging pixel arranged between focus detection pixels is considered to consist of a plurality of divided regions, the arithmetic control unit 105 calculates a focus detection signal from pixel values obtained in the respective regions together with pixel values of focus detection pixels. A focus detection unit 108 performs imaging plane phase difference detection by pupil division using the focus detection signal calculated from pixel values of focus detection pixels and pixel values of imaging pixels.SELECTED DRAWING: Figure 1

Description

  The present invention relates to signal processing of an image sensor having a focus detection pixel and an imaging pixel, and more particularly to arithmetic processing for obtaining a focus detection signal.

  In focus detection using the pupil division phase difference method, a pair of pupil division images obtained by dividing the light beam passing through the photographing lens is used. By detecting an image shift between the pair of pupil divided images, the defocus amount and the defocus direction of the photographing lens can be detected. In accordance with this principle, there is a solid-state image sensor including a focus detection pixel in which a light shielding layer is formed on a pixel of the image sensor. Patent Document 1 discloses a method of performing pupil division phase difference type focus detection using a solid-state imaging device in which focus detection pixels are embedded between normal pixels.

Japanese Patent No. 4797606

  In the technique disclosed in Patent Document 1, since an imaging pixel is lost at the position of the focus detection pixel, it is necessary to generate an image by interpolating from surrounding imaging pixels. For this reason, the higher the ratio of the number of focus detection pixels to the total number of pixels, the easier it is for image quality degradation to occur. If the distribution density (or arrangement density) of the focus detection pixels is lowered on the imaging surface in order to suppress the deterioration of the image quality, the focus detection accuracy is lowered. Therefore, an object of the present invention is to provide a calculation process of a focus detection signal that can suppress a decrease in focus detection accuracy even when the distribution density of focus detection pixels is low in an image sensor.

  An apparatus according to the present invention is an image pickup apparatus including a focus adjustment lens constituting an image pickup optical system, a focus detection pixel that receives light that has passed through a microlens, and an image pickup device having an image pickup pixel, the focus adjustment described above. Lens driving means and calculation means for calculating a focus detection signal from the pixel value of the imaging pixel and the pixel value of the focus detection pixel are provided. The calculation means includes a first pixel signal output from the focus detection pixel and the imaging pixel by the first exposure through the focus adjustment lens, and the drive means passes the focus adjustment lens in the first exposure. A second pixel signal output from each of the focus detection pixel and the imaging pixel is obtained by a second exposure moved from the position in the optical axis direction, and photoelectric conversion of the imaging pixel disposed between the focus detection pixels is performed. When a part is composed of a plurality of divided areas, the focus detection signal is calculated from the pixel value of the imaging pixel and the pixel value of the focus detection pixel by calculating the pixel signal obtained in each area. To do.

  ADVANTAGE OF THE INVENTION According to this invention, even when the distribution density of a focus detection pixel is low in an image sensor, the calculation process of the focus detection signal which can suppress the fall of focus detection accuracy can be provided.

1 is a block diagram of an imaging apparatus according to an embodiment of the present invention. It is pixel sectional drawing (A) of the image pick-up element concerning 1st Embodiment, and pixel cross-sectional view (B) of the image pick-up element concerning 2nd Embodiment. It is a figure which illustrates the pixel arrangement | sequence of an image pick-up element. It is a relationship diagram of an image sensor and light rays. It is an array figure of a virtual focus detection pixel. It is a flowchart explaining the process example in 1st Embodiment. It is a flowchart explaining the process example in 3rd Embodiment.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[First Embodiment]
Before describing the configuration of the imaging apparatus illustrated in FIG. 1, the structure of the imaging element will be described. FIG. 2A is a cross-sectional view schematically showing a pixel structure of an image sensor used in the present embodiment. FIG. 2A shows one imaging pixel (imaging pixel) and one focus detection pixel (focus detection pixel). Each pixel includes a microlens 201, and a wiring layer 202 is provided. The photoelectric conversion unit 203 of the imaging pixel photoelectrically converts the light received through the microlens 201 and outputs an electrical signal. For the photoelectric conversion unit 204 of the focus detection pixel, a light shielding unit 205 that performs partial light shielding using a wiring is formed. The photoelectric conversion unit 204 receives the light partially blocked by the light shielding unit 205 through the microlens 201, performs photoelectric conversion, and outputs an electrical signal. In imaging plane phase difference detection, a plurality of focus detection pixels having such a structure are arranged to obtain a pupil-divided image signal.

FIG. 3 is a layout diagram illustrating a pixel array of 5 rows and 8 columns, which is a part of the image sensor.
The imaging pixels 301 indicated by a circular frame are arranged in a two-dimensional array, and focus detection pixels 302 and 303 indicated by semicircular frames are arranged in a distributed manner. The imaging pixel 301 performs photoelectric conversion over the entire light receiving surface. Since the focus detection pixels 302 and 303 include the light shielding portion 205 illustrated in FIG. 2A, photoelectric conversion is performed on light received by a part of the light receiving surface. The detection principle will be described below with reference to FIG. 4 according to the arrangement illustrated in FIG.

  FIG. 4 is a schematic diagram for explaining the pixel array and the calculation contents. The light beams incident on the six imaging pixels 301 shown in the third row of FIG. 3 and the focus detection pixels 302 and 303 are shown. For convenience of explanation, identification symbols indicated by P0 to P7 and Q0 to Q6 are given to the respective pixels, and the respective pixel values are similarly expressed by P0 to P7 or Q0 to Q6. For example, P0 and Q0 represent pixel values of the focus detection pixel 302, and P6 and Q6 represent pixel values of the focus detection pixel 303. P1 to P5 and Q1 to Q5 represent pixel values of the imaging pixel 301 corresponding to each.

  The upper part of FIG. 4 shows the pixel array on the imaging surface and the pixel values in the pixel array direction in the first exposure. The first pixel signal obtained by the first exposure is indicated by respective pixel values P0 to P7. The lower part shows a pixel array on the imaging surface in the second exposure, and the second pixel signal obtained by the second exposure is indicated by respective pixel values Q0 to Q6.

  The imaging surface in the second exposure is separated from the imaging surface in the first exposure by a focal plane distance A in the optical axis direction. By driving the focus adjustment lens (focus lens), the image divided by moving the lens moves in the pupil division direction. When the ratio of the movement amount of the pupil-divided image and the movement amount of the focus lens is denoted as a K value, the K value is determined by the distance to the pupil plane and the shape of the pupil. Therefore, the K value can be obtained by calculation from the lens design information, the current aperture value, the position information of the focus lens, and the like.

  In the first exposure, among the incident light to the focus detection pixel 302, an area that is not photoelectrically converted due to being shielded by the light shielding portion is distinguished by adding B0, and its output value is denoted by B0. In addition, A0 is added to an area that is photoelectrically converted in the incident light to the focus detection pixel 302 to distinguish it, and an output value thereof is indicated as A0. That is, the sum of the output value B0 in the light-shielded area and the output value A0 in the non-light-shielded area is the pixel value P0. In addition, a subscript i of a natural number variable is introduced, and the pixel values Pi (i = 1 to 5, 7) are distinguished from each other by adding Ai and Bi to the two areas, and the output values of each area are set to Ai, Bi. . For example, the pixel value P1 is equal to the sum of A1 and B1. Only the output value A7 is shown for the imaging pixel P7 located at the right end in the pixel array direction in FIG.

  On the other hand, among the incident light to the focus detection pixel 303 (see P6), an area where photoelectric conversion is performed without being shielded by the light shielding portion is distinguished by attaching A6, and the output value is denoted as A6. Since the incident light to the area A6 is received as half of the incident light to P6, it corresponds to light incident from an eccentric angle with respect to the optical axis center of the pixel. Assuming that the luminous flux photoelectrically converted in the area A6 in the pixel P6 is shifted by exactly one pixel in the pixel arrangement direction (left-right direction in FIG. 4), the focal plane distance at that time is defined as the focal plane distance A. And The focal plane distance A is calculated by multiplying the pixel pitch (distance) in the direction orthogonal to the optical axis direction by the K value. In the present embodiment, a process of calculating the focal plane distance A is executed based on the lens design information and control information, and after the drive control for shifting the focus lens by the focal plane distance A is performed, the second exposure is executed. The

  The pixel values Q0 to Q6 of the signal obtained by the second exposure will be described. The pixel value Q0 corresponds to the output value A1 that is photoelectrically converted by the pixel P1. The reason is that the received light amount corresponding to the output value A1 is not blocked by Q0. The pixel value Q1 corresponds to the sum of the output value A2 at P2 and the output value B0 at P0. The pixel value Q2 corresponds to the sum of the output value A3 of P3 and the output value B1 of P1. Thereafter, pixel values Q3 to Q6 are obtained in the same manner.

  The five image pickup pixels located between the focus detection pixels 302 and 303 are not intrinsically focus detection pixels. However, since the pixel value Pi (i = 1 to 5) is the sum of the output values of the two divided areas Ai and Bi, it can be used as a focus detection pixel if the values of Ai and Bi can be calculated respectively. . That is, by obtaining the A image signal from each output value in the area Ai and obtaining the B image signal from each output value in the area Bi, the image shift amount can be calculated from the correlation calculation result of both. In this sense, an imaging pixel having each of A1 to A5 and B1 to B5 as a set is referred to as a “virtual focus detection pixel”. Hereinafter, calculation processing for calculating the output values of the areas Ai and Bi will be described.

The relationship between the pixel values P0 to P6 and A0 to A6 and B1 to B5 in the first exposure can be expressed by the following equation.

The relationship between the pixel values Q0 to Q6, A1 to A7, and B0 to B4 in the second exposure can be expressed by the following equation.

A0 (= P0) and A6 (= P6) are known in the first exposure, and A1 (= Q0) and A7 (= Q6) are known in the second exposure. Therefore, the pixel values of the remaining virtual focus detection pixels can be obtained from these values. Specifically, the pixel value of the virtual focus detection pixel is calculated from the following equation by calculating backward from Equation 1 and Equation 2.

  By using the pixel value of the virtual focus detection pixel obtained in this way, it is substantially equivalent to a pixel structure in which focus detection elements are densely arranged together with focus detection pixels 302 and 303 as shown in FIG. Can be realized. That is, as shown by the two-divided pixels 501 in the third row in FIG. 5, focus detection performance equivalent to that when the focus detection pixels are arranged at a high density is obtained. The first focus detection signal and the second focus detection signal can be acquired using the pixel value of each pixel 501, and a signal obtained by adding both signals can be used as an imaging signal. In the above formula, pixel values P0 to P6 are described in consideration of easy understanding. In the case of a pixel structure in which the same arrangement is further continued, the pixel value of the virtual focus detection pixel having a longer arrangement can be calculated by applying an expression expanded according to the number of arranged pixels. it can.

Next, a configuration example of the imaging apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram of a configuration unit in which portions related to the present invention are extracted from the configuration of the imaging apparatus.
The lens unit 101 constituting the imaging optical system includes optical elements such as a diaphragm and a focus lens. When the lens unit 101 has a zoom mechanism, a zoom lens and its position detection unit are provided. The image sensor 102 (see FIGS. 2 and 3) photoelectrically converts light that forms an image through the lens unit 101, and outputs each pixel signal of the imaging pixel and the focus detection pixel. A missing imaging pixel interpolation unit (hereinafter referred to as a pixel interpolation unit) 103 acquires a signal of a focus detection pixel from the imaging element 102 and also acquires and interpolates a signal of an imaging pixel located around the focus detection pixel. Since the signal at the position of the focus detection pixel is generated by the interpolation process by the pixel interpolation unit 103, an image pickup pixel signal is obtained over the entire image pickup surface as in the case of a normal image pickup element. The imaging pixel signal and a signal calculated by interpolation processing at the position of the focus detection pixel are output to the signal processing unit 104. The signal processing unit 104 executes signal processing suitable for image data recording processing and image display processing according to a predetermined format. Since the processing performed by the circuit units after the signal processing unit 104 is not essential in the present invention, the description thereof is omitted.

  A virtual focus detection pixel calculation control unit (hereinafter referred to as a calculation control unit) 105 acquires a signal output from the image sensor 102 and performs calculation control of the virtual focus detection pixel. The arithmetic control unit 105 is connected to a first image memory 107 that stores a signal acquired by the first exposure and a second image memory 106 that stores a signal acquired by the second exposure. The signal acquired by the first exposure is a signal of pixel values P0 to P7 in the above example, and the signal acquired by the second exposure is a signal of pixel values Q0 to Q6 in the above example. The calculation control unit 105 calculates the pixel value of the virtual focus detection pixel by the above calculation and outputs it to the focus detection unit 108 together with the pixel values of the focus detection pixels 302 and 303. The focus detection unit 108 performs a known correlation calculation based on the pixel values of the focus detection pixel and the virtual focus detection pixel, calculates an image shift amount by detecting the imaging surface phase difference, and converts it to a defocus amount.

  The lens control unit 109 controls optical elements such as a diaphragm and a focus lens of the lens unit 101. The arithmetic control unit 105 transmits a control signal to the lens control unit 109 when the second exposure is controlled and when the focus adjustment operation is controlled based on the focus detection result by the focus detection unit 108. The focus detection unit 108 generates a pair of image (A image and B image) data based on the pixel values of the focus detection pixel and the virtual focus detection pixel, and detects the defocus amount using the phase difference. The lens control unit 109 controls the focus adjustment operation by driving the focus lens based on the defocus amount detected by the focus detection unit 108. The output 801 and the temporary storage memory 802 will be described in an embodiment described later.

  FIG. 6 is a flowchart illustrating an example of processing performed by the arithmetic control unit 105. The following processing is performed according to a program executed by a CPU (central processing unit) of a system control unit that controls the entire imaging apparatus.

  In S601, the process starts with a synchronization signal from the system control unit, and the process proceeds to S602. In S602, the first exposure is performed. Since it is desirable that the focal position in the first exposure be as close as possible to the in-focus state, the focus detection unit 108 performs rough focus detection before the calculation control unit 105 starts operation. The image data obtained by the first exposure is transferred to the first image memory 107 and stored therein. The first image memory 107 does not need to store data for the entire screen, and stores data indicating the pixel values of the focus detection pixels and the image pickup pixels necessary for the calculation in the vicinity of the focus detection pixels. The The same applies to data stored in the second image memory 106 in the second exposure described later.

  In step S <b> 603, the arithmetic control unit 105 calculates a focal plane distance A in order to determine the focal position in the second exposure. The focal plane distance A is calculated from the focal length, the aperture value, and the base length of pupil division determined by the zoom lens position in the case of a lens unit having a zoom mechanism. A value K indicating the focal plane distance and the lateral shift magnification of the image can be obtained from the baseline length. Then, the focal plane distance A corresponding to the image shift amount for one pixel is calculated. In step S <b> 604, the arithmetic control unit 105 transmits a control signal to the lens control unit 109 in order to move the focus lens by a distance corresponding to the focal plane distance A, and waits for completion of lens control. In the next S605, the second exposure is performed. The time from the first exposure time to the second exposure time is preferably as short as possible. The image data obtained by the second exposure is transferred to the second image memory 106 and stored therein.

  In S <b> 606, the arithmetic control unit 105 calculates the pixel value of the virtual focus detection pixel by applying Equation 3 based on the image data in the first exposure and the second exposure. The calculated pixel value data is transferred to the focus detection unit 108 in S607, and a focus detection process is executed. In other words, the focus detection unit 108 starts the focus detection process in response to receiving the pixel value data of the virtual focus detection pixel. The lens control unit 109 executes known focus adjustment control based on the phase difference detection information, and moves the focus lens to the in-focus position.

  In the present embodiment, the pixel value of the virtual focus detection pixel can be calculated by the above-described calculation using the pixel values acquired in the first exposure and the second exposure according to such a procedure. That is, in the second exposure, the imaging pixel and the focus detection pixel receive light incident with a shift of the pixel pitch with respect to the first exposure, and output a pixel value. Pixel signal in an area divided by virtual focus detection pixels (imaging pixels located between the focus detection pixels in the pixel arrangement direction) from the difference between the pixel signal at the second exposure and the pixel signal at the first exposure Can be calculated. Therefore, not only a focus detection pixel signal having a lower distribution density than the image pickup pixel on the image pickup surface but also a focus detection pixel signal having a high distribution density including the virtual focus detection pixel can be obtained, while suppressing deterioration in image quality. The accuracy of focus detection can be improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, the same constituent elements as those in the first embodiment are denoted by the same reference numerals as those used in the first embodiment, and detailed descriptions thereof are omitted, and differences are mainly described. Omitting such description is the same in the embodiments described later.

  FIG. 2B illustrates a cross-sectional structure of the image sensor according to this embodiment. The focus detection pixel does not have a light shielding portion, and has photoelectric conversion units 701 and 702 that are half the size of the photoelectric conversion unit 203 of a normal pixel. Both the photoelectric conversion units 701 and 702 share the same microlens 201. With this structure, pupil division is possible in the same manner as in the case of having a light shielding portion as in the first embodiment. When the focus detection pixels in FIG. 2B are arranged in the same arrangement as in FIG. 4, pixels whose pixel values are known are A0, B0, A1, B1, A6, B6, A7, and B7. Therefore, in this embodiment, the reliability and accuracy by verification are improved by the amount of pixel information, compared to the case of the first embodiment.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In FIG. 1, the difference between the present embodiment and the first embodiment is as follows.
The arithmetic control unit 105 transfers the pixel information of the virtual focus detection pixel to the pixel interpolation unit 103 as an output 801.
A temporary storage memory 802 is connected to the pixel interpolation unit 103 and temporarily stores image data at the time of main exposure.
The main exposure is exposure performed to record captured image data on a recording medium or the like, and is distinguished from first exposure and second exposure for focus detection. For example, when exposure is performed separately from the first exposure and the second exposure, the exposure is the main exposure. However, in order to reduce the number of exposures, either the first exposure or the second exposure may be used for the main exposure, and both the first exposure and the second exposure may be used for the main exposure. In that case, the pixel interpolation unit 103 corrects and records the pixel values acquired by the first exposure or the second exposure, or the first exposure and the second exposure. The structure of the image sensor is the same as that of the first embodiment (see FIGS. 2 and 4).

In the present embodiment, a case where main exposure and subsequent exposure (third exposure) are performed will be described. Pixel value data of the virtual focus detection pixel using the image data in the main exposure is created. Based on the created pixel value data of the virtual focus detection pixels, the pixel values B0 and B6 of the pixel missing portions of P0 and P6 are added to the pixel values P0 and P6, respectively, to correct the pixel values. .
FIG. 7 is a flowchart for explaining processing of the arithmetic control unit 105 synchronized with photographing by the main exposure according to the present embodiment. When a system control unit (not shown) gives an instruction to shift to shooting control by main exposure, the process of S901 starts.

  In step S <b> 902, the main exposure is performed, and the pixel signal read from the image sensor 102 is input to the pixel interpolation unit 103 and the calculation control unit 105. The arithmetic control unit 105 stores the pixel signal obtained by the main exposure in the first image memory 107. In addition, the pixel interpolation unit 103 stores the image data obtained by the main exposure in the temporary storage memory 802.

  In S903, the focal plane distance A is calculated as in the case of the first embodiment. In step S904, the lens control unit 109 executes control to move the focus lens according to the focal plane distance A. In step S <b> 905, the arithmetic control unit 105 performs third exposure, and stores pixel data in the vicinity of the focus detection pixel in the second image memory 106. In S906, the arithmetic control unit 105 calculates the pixel value of the virtual focus detection pixel using the calculation formula described in the first embodiment based on the pixel values of the image by the main exposure and the image by the third exposure. In S907, the calculation control unit 105 outputs the pixel value of the virtual focus detection pixel to the pixel interpolation unit 103 (FIG. 1: output 801). The pixel interpolation unit 103 acquires image data obtained by main exposure stored in the temporary storage memory 802. The pixel interpolation unit 103 corrects the pixel value so that it can be used as an imaging pixel value by adding a pixel value corresponding to the amount of light that should be incident on the focus detection pixel when there is no light shielding unit. To do. Specifically, correction is performed by adding pixel values B0 and B6, which are missing portions of P0 and P6, to pixel values P0 and P6, respectively. The pixel value B6 is calculated in the same manner as in the case of B0 by using the pixel values of the pixels P7 to P12 in a structure in which the same pixel arrangement as P0 to P6 in FIG. 4 is continuously repeated.

  In the present embodiment, after the main exposure, pixel correction at the position of the focus detection pixel can be performed using the calculated pixel value of the virtual focus detection pixel, which contributes to improving the image quality of the captured image and the recorded image. . In the above embodiment, the pupil division is described as being divided into two. However, the present invention is not limited to this, and a structure having a plurality of photoelectric conversion units divided for one microlens is possible, and more pupil divisions than two divisions such as four divisions or nine divisions may be performed.

DESCRIPTION OF SYMBOLS 102 ... Image pick-up element 103 ... Missing imaging pixel interpolation part 105 ... Virtual focus detection pixel calculation control part 106 ... 2nd image memory 107 ... 1st image memory 108 ... Focus detection part 203 ... Photoelectric conversion part 204,701,702 of an imaging pixel ... Photoelectric conversion part of focus detection pixel

Claims (11)

An imaging apparatus comprising: a focus adjustment lens that constitutes an imaging optical system; a focus detection pixel that receives light that has passed through each microlens; and an imaging element that includes the imaging pixel.
Driving means for the focusing lens;
Computation means for computing a focus detection signal from the pixel value of the imaging pixel and the pixel value of the focus detection pixel,
The calculation means includes a first pixel signal output from the focus detection pixel and the imaging pixel by the first exposure through the focus adjustment lens, and the drive means passes the focus adjustment lens in the first exposure. A second pixel signal output from each of the focus detection pixel and the imaging pixel is obtained by a second exposure moved from the position in the optical axis direction, and photoelectric conversion of the imaging pixel disposed between the focus detection pixels is performed. When a part is composed of a plurality of divided areas, the focus detection signal is calculated from the pixel value of the imaging pixel and the pixel value of the focus detection pixel by calculating the pixel signal obtained in each area. An imaging apparatus characterized by:   The imaging apparatus according to claim 1, further comprising a control unit that calculates a defocus amount from the focus detection signal by the calculation unit and performs focus adjustment by moving the focus adjustment lens by the driving unit. .   Correction means for acquiring the focus detection signal by the calculation means and correcting a pixel value at the position of the focus detection pixel using a pixel value of the imaging pixel arranged around the focus detection pixel; The imaging apparatus according to claim 1, wherein the imaging apparatus is characterized.   The calculation means calculates a focal plane distance in an optical axis direction corresponding to a distance between the imaging surface in the second exposure and the imaging surface in the first exposure from the aperture value and the position of the focus adjustment lens. The imaging apparatus according to claim 1, wherein a focal position in the second exposure is determined.   The imaging apparatus according to claim 4, wherein the calculation unit calculates the focal plane distance from an aperture value, a position of the focus adjustment lens, and a zoom lens position when a zoom mechanism is provided.   The computing means calculates the ratio of the movement amount of the pupil-divided image and the movement amount of the focus adjustment lens, and multiplies the pixel pitch in the pixel arrangement direction orthogonal to the optical axis direction by multiplying the focal plane by the focal plane. 6. The imaging apparatus according to claim 4, wherein a distance is calculated. The calculation means acquires the image data captured from the first pixel signal in the first exposure, and then acquires the second pixel signal in the second exposure to calculate the focus detection signal. And
The correction means acquires the focus detection signal from the calculation means, corrects and records the pixel values acquired in the first exposure or the second exposure, or the first exposure and the second exposure. The imaging device according to claim 3.   The imaging apparatus according to claim 1, wherein the focus detection pixel includes a light shielding unit that shields light incident on the photoelectric conversion unit.   The imaging apparatus according to claim 1, wherein the focus detection pixel includes a plurality of photoelectric conversion units that share the microlens. In the second exposure, the imaging pixel and the focus detection pixel respectively receive light that is shifted by a pixel pitch in the pixel arrangement direction with respect to the first exposure, and output a pixel value.
The calculation means calculates a pixel signal in a region divided into a plurality by the imaging pixel from a difference between the second pixel signal and the first pixel signal. The imaging device according to any one of the above. A control method executed in an imaging apparatus including a focus adjustment lens and its driving means constituting an imaging optical system, and an imaging element having a focus detection pixel and an imaging pixel that receive light that has passed through a microlens, respectively. ,
A first pixel signal output from each of the focus detection pixel and the imaging pixel by the first exposure through the focus adjustment lens, and the driving means moves the focus adjustment lens from the position at the first exposure to the optical axis direction. A calculating means for obtaining a second pixel signal respectively output from the focus detection pixel and the imaging pixel by the second exposure moved to
By calculating the pixel signal obtained in each region when the photoelectric conversion unit of the imaging pixel arranged between the focus detection pixels is composed of a plurality of divided regions, A control method comprising a step of calculating a focus detection signal from a pixel value of the imaging pixel and a pixel value of the focus detection pixel.

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