JP6611559B2 - IMAGING DEVICE, ITS CONTROL METHOD, PROGRAM, AND STORAGE MEDIUM - Google Patents

Description

  The present invention relates to an imaging apparatus. More specifically, the present invention relates to focus adjustment in an imaging apparatus.

  A technique for adjusting a focal position arbitrarily by a user is known. For example, in Patent Document 1, a plurality of images with different focal positions are obtained by driving a photographing lens, and a user selects an image photographed at a focal position in a desired focal state from among the plurality of images. To do. In the camera of Patent Document 1, the EEPROM stores adjustment values for focus adjustment corresponding to the image selected by the user. Since the stored adjustment value is reflected in the focus adjustment after the next time and a focus state different from the focus before the adjustment value is reflected can be maintained, it is possible to save the user from making adjustments each time.

JP 2011-48341 A

  As described above, in Patent Document 1, it is necessary to perform continuous shooting with different focal positions in order to adjust the focal position. In continuous shooting, a time difference occurs between the first and last images that can be acquired. When the time difference occurs, for example, when the subject moves, the positions of the subjects do not match in the plurality of images to be acquired. In such a case, compared with the case where the subject is a stationary subject, it is difficult to understand the difference in the focal position between the plurality of images.

  An object of the present invention is to provide an imaging apparatus that can easily compare differences in focus state between a plurality of images. It is another object of the present invention to provide a control method, a program, and a storage medium for such an imaging apparatus.

The present invention includes an imaging device having a plurality of pixel units each having a plurality of photoelectric conversion units that respectively receive and photoelectrically convert light beams that have passed through different pupil regions of an optical system, a focus detection unit that detects a defocus amount, Generation of generating a plurality of refocused images using a focus adjustment unit that drives a focus lens based on a defocus amount and adjusts a focal position, and signals having different focal positions acquired from the plurality of photoelectric conversion units. And a storage unit that stores an adjustment value for adjusting the focal position corresponding to the refocus image generated by the generation unit, and the focus adjustment unit stores the adjustment stored in the storage unit. The focus position is adjusted based on the value.

  According to the present invention, it is easy to compare the difference in focus state between a plurality of images as compared with the prior art.

The block diagram of a digital camera (imaging device). The figure which shows the arrangement | sequence of a pixel part. FIG. 6 is a relationship diagram between a defocus amount and an image shift amount of a first focus detection signal and a second focus detection signal. Explanatory drawing of the focus detection area | region in a present Example. The flowchart which shows the process of the 1st focus detection in a present Example. Explanatory drawing of the shading by the pupil shift | offset | difference of the 1st focus detection signal and 2nd focus detection signal in a present Example. The figure which shows an example of the filter frequency band in a present Example. The figure which shows an example of the 1st focus detection signal and 2nd focus detection signal in a present Example. The figure which shows an example of the 1st focus detection signal after a 1st filter process in case a focus lens exists in a focus position, and a 2nd focus detection signal. FIG. 6 is a diagram illustrating an example of a first detection defocus amount and a second detection defocus amount according to the first embodiment. Explanatory drawing of the best focus adjustment value in a present Example. Explanatory drawing of the refocus image generation process in a present Example. Explanatory drawing of the refocus possible range in a present Example. 6 is a flowchart illustrating focus position adjustment value setting according to the first embodiment. 9 is a flowchart illustrating focus position adjustment value setting according to the second embodiment. FIG. 10 is a diagram illustrating a data structure of an EEPROM according to the third embodiment. The flowchart which shows the process of a 2nd focus detection. 10 is a flowchart illustrating focus position adjustment value setting according to the third embodiment. 10 is a flowchart illustrating focus position adjustment value setting (when a plurality of recorded images are generated) according to a third embodiment.

  Embodiments to which the present invention is applied will be described below with reference to the accompanying drawings. In addition, the following examples are examples of the form to which the present invention is applied, and can be appropriately changed without departing from the gist of the present invention.

[Example 1]
FIG. 1 is a block diagram of the digital camera (imaging device) of this embodiment. The digital camera of this embodiment is an interchangeable lens type single-lens reflex camera, and the lens unit 100 can be attached to and detached from the camera body 120. The lens unit 100 is connected to the camera body 120 via a mount M indicated by a dotted line in the center of the drawing.

[Configuration of lens unit]
The lens unit 100 includes a first lens group 101, a second lens group 102, a third lens group 103, and a drive / control system. As described above, the lens unit 100 includes the focus lens 103 and includes a lens unit that forms an image of a subject.

  The first lens group 101 is disposed at the tip of the lens unit 100 and is held so as to be able to advance and retreat in the optical axis direction OA.

  The second lens group 102 moves back and forth in the optical axis direction, and can achieve a zooming action (zoom function) in conjunction with the forward and backward movement of the first lens group 101.

  A third lens group (hereinafter referred to as a focus lens) 103 performs focus adjustment by moving back and forth in the optical axis direction.

[Lens unit drive / control system]
The drive / control system includes a focus actuator 110, a focus drive circuit 111, a lens MPU 112, a lens memory 113, a zoom actuator 114, and a zoom drive circuit 115.

  The focus actuator 110 performs focus adjustment by driving the focus lens 103 back and forth in the optical axis direction OA. The focus actuator 110 has a function as a position detection unit that detects the current position of the focus lens 103.

  The focus drive circuit 111 drives and controls the focus actuator 110 based on the focus detection result, and performs focus adjustment by driving the focus lens 103 back and forth in the optical axis direction OA.

  The zoom actuator 114 rotates a cam cylinder (not shown) to drive the first lens group 101 and the second lens group 102 forward and backward in the optical axis direction, thereby performing a zooming operation.

  The lens MPU 112 performs all calculations and control related to the lens unit, and controls the focus driving circuit 111 and the lens memory 113. Further, the lens MPU 112 detects the current lens position, and notifies the lens position information in response to a request from the camera MPU 124. The lens memory 113 stores optical information necessary for automatic focus adjustment.

[Configuration of Camera Body 120]
The camera body 120 includes an optical low-pass filter 121, an image sensor 122, and a drive / control system.

  The optical low-pass filter 121 and the imaging element 122 function as an imaging optical system that forms a subject image with the light flux from the lens unit 100. The optical low-pass filter 121 reduces the false color and moire of the image.

  The image sensor 122 is composed of a CMOS sensor and its peripheral circuits, and one photoelectric conversion element is arranged on the light receiving pixels of m pixels in the horizontal direction and n pixels in the vertical direction. The image sensor 122 is configured to be able to output all pixels independently. In addition, some or all of the pixels are focus detection pixels, and focus detection (imaging surface phase difference AF) using a phase difference detection method on the imaging surface is possible.

[Camera body drive / control system]
The drive / control system includes an image sensor driving circuit 123, a camera MPU 124, an image processing circuit 125, an imaging surface phase difference focus detection unit 126, a display unit 127, an operation switch (SW) group 128, and a memory 129.

  The image sensor drive circuit 123 controls the operation of the image sensor 122, A / D converts the acquired recorded image signal and focus detection signal, and transmits them to the camera MPU 124.

  The image processing circuit 125 performs γ conversion, color interpolation, JPEG compression, and the like of the image acquired by the image sensor 122.

  Further, the image processing circuit 125 (generation unit) can generate a refocus image in which the focal position is arbitrarily changed from the recorded image signal acquired by the image sensor 122. The refocus image is an image corresponding to an image on a virtual imaging plane different from the current imaging plane. Details of the generation of the refocus image will be described later.

  The camera MPU (control unit, processor) 124 performs all calculations and controls related to the camera body 120. The camera MPU 124 controls the image sensor driving circuit 123, the image processing circuit 125, the imaging surface phase difference focus detection unit 126, the display unit 127, the operation SW 128, and the memory 129.

  The camera MPU 124 is connected to the lens MPU 112 via the signal line of the mount M, and obtains a lens position, issues a lens driving request with a predetermined driving amount, and sends optical information specific to the lens unit 100 to the lens MPU 112. Or get it. Therefore, the camera MPU 124 can acquire the information from the lens MPU 112 when a lens with a large image magnification change is attached. The camera MPU 124 includes an EEPROM 124a that stores various parameters including adjustment values used at the time of focus detection, a RAM 124b that stores variables, and a ROM 124c that stores programs for controlling camera operations.

  The imaging surface phase difference focus detection unit 126 performs a first focus detection process by an imaging surface phase difference method based on image signals acquired by a plurality of photoelectric conversion units included in the pixel unit of the imaging element 122. Details of the imaging plane phase difference AF will be described later.

  The display unit 127 includes an LCD or the like, and displays information related to the shooting mode of the camera, a preview image before shooting and a confirmation image after shooting, a display image of the focus state at the time of focus detection, and the like.

  The operation SW group 128 includes a power switch, a release (imaging trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. The memory 129 is a detachable flash memory and records captured images.

  The defocus detection unit 134 includes a line sensor that photoelectrically converts received light to acquire an electric signal for acquiring a signal to be used for AF, and an object image guided by a focus detection optical system (not shown). Is photoelectrically converted and output as a potential change. The mirror drive unit 133 retracts the quick return mirror composed of the main mirror 131 and the sub mirror 132 at the start of shooting and returns it when the shooting is completed. It should be noted that the defocus detection unit 134 may be omitted when the image sensor that performs the focus detection (imaging surface phase difference AF) of the phase difference detection method on the imaging surface is provided as in the present embodiment.

[Configuration of imaging surface phase difference AF]
The image sensor 122 includes a plurality of pixel units that each receive light passing through the entire exit pupil of a lens unit that forms an image of a subject to generate an image of the subject. Each pixel unit includes a plurality of photoelectric conversion units that receive light passing through a partial region of the exit pupil of the lens unit. In the first embodiment, each pixel unit includes a first photoelectric conversion unit and a second photoelectric conversion unit. However, each pixel unit may include more than two photoelectric conversion units.

  FIG. 2 shows an array of pixel portions of the two-dimensional CMOS sensor (imaging device) of this embodiment in a range of 4 columns × 4 rows, and an array of photoelectric conversion portions in a range of 8 columns × 4 rows. .

  The pixel group 200 is composed of 2 × 2 pixel units. A pixel unit 200R having a spectral sensitivity of R (red) is on the upper left, a pixel unit 200G having a spectral sensitivity of G (green) is on the upper right and lower left, and B A pixel portion 200B having a spectral sensitivity of (blue) is arranged at the lower right. Further, each pixel unit includes a first photoelectric conversion unit 201 and a second photoelectric conversion unit 202 arranged in 2 columns × 1 row.

  A large number of 4 columns × 4 rows of pixels (8 columns × 4 rows of focus detection pixels) shown in FIG. 2 are arranged on the surface, and a captured image and focus detection signals can be acquired.

  In this embodiment, a case where the pupil region is divided into two pupils in the horizontal direction will be described, but pupil division may be performed in the vertical direction.

  In the present embodiment, the light reception signals of the first photoelectric conversion unit 201 of each pixel of the image sensor 122 are collected to generate a first focus detection signal, and the light reception signals of the second photoelectric conversion unit 202 of each pixel are collected. A second focus detection signal is generated to perform focus detection. Further, a recording image signal is generated by adding the signals of the first photoelectric conversion unit 201 and the second photoelectric conversion unit 202 to each pixel unit of the image sensor 122.

  In the above-described example, a plurality of pixel units each including the first photoelectric conversion unit and the second photoelectric conversion unit are arranged, but the present invention is not limited to this. The pixel unit for acquiring the recording image signal and the pixel unit for acquiring the focus detection signal may be separate pixel units. In this case, for example, the pixel unit for acquiring the focus detection signal may be partially arranged in a part of the array of the pixel unit for acquiring the recording image signal.

  The relationship between the defocus amounts of the first focus detection signal and the second focus detection signal acquired by the image sensor 122 of the present embodiment and the image shift amount will be described below. FIG. 3 is a relationship diagram of the defocus amounts of the first focus detection signal and the second focus detection signal and the image shift amount between the first focus detection signal and the second focus detection signal. The imaging element 122 of the present embodiment is arranged on the imaging surface 320, and the exit pupil of the imaging optical system is divided into two parts, a first pupil partial region 311 and a second pupil partial region 312.

  The defocus amount d is a distance | d | from the imaging position of the subject to the imaging surface, a negative sign (d <0) indicates a front pin state in which the imaging position of the subject is closer to the subject than the imaging surface, Is defined as a positive sign (d> 0). In the focus state when the imaging position of the subject is the imaging surface, that is, in focus, d = 0. In FIG. 3, the subject 301 shows an example of a focus state (d = 0), and the subject 302 shows an example of a front pin state (d <0). The front pin state (d <0) and the rear pin state (d> 0) are combined to form a defocus state (| d |> 0).

  In the front pin state (d <0), the light flux that has passed through the first pupil partial region 311 (second pupil partial region 312) out of the light flux from the subject 302 is once condensed and then the gravity center position G1 of the light flux. The image spreads in the width Γ1 (Γ2) with (G2) as the center, and the image is blurred on the imaging surface 320. The blurred image is received by the first photoelectric conversion unit 201 (second photoelectric conversion unit 202) constituting each pixel arranged in the image sensor 122, and the first focus detection signal (second focus detection signal) is received. Generated. Therefore, the first focus detection signal (second focus detection signal) is recorded as a subject image in which the subject 302 is blurred by the width Γ1 (Γ2) at the gravity center position G1 (G2) on the imaging surface 320. The blur width Γ1 (Γ2) of the subject image generally increases in proportion to the amount of defocus amount d | d |. Similarly, the magnitude | p | of the object image displacement amount p (= difference G1-G2 in the center of gravity of the light beam) between the first focus detection signal and the second focus detection signal is also the size of the defocus amount d. As | d | increases, it generally increases in proportion. Even in the rear pin state (d> 0), the image shift direction of the subject image between the first focus detection signal and the second focus detection signal is opposite to that in the front pin state, but the same.

  As described above, the first focus detection signal and the second focus detection signal, or the defocus amount of the recording image signal obtained by adding the first focus detection signal and the second focus detection signal increases. The amount of image shift between the first focus detection signal and the second focus detection signal increases.

  In the present embodiment, first focus detection (described later) using a phase difference method on the imaging surface is performed using the relationship between the defocus amount and the image shift amount of the first focus detection signal and the second focus detection signal.

[Focus detection area]
First, a focus detection area that is an area on the image sensor 122 that acquires the first focus detection signal and the second focus detection signal will be described. FIG. 4 shows the focus detection area in the effective pixel area 400 of the image sensor 122 and the index indicating the focus detection area displayed on the display unit 127 during focus detection. In this embodiment, there are nine focus detection areas, three in the row direction and three in the column direction. The nth focus detection region in the row direction and the mth focus detection region in the column direction is represented as A (n, m), and using the signals of the first photoelectric conversion unit 201 and the second photoelectric conversion unit 202 in this region, First focus detection described later is performed. Similarly, the index of the nth focus detection region in the row direction and the mth focus detection region in the column direction is represented as I (n, m).

  In this embodiment, an example is shown in which three focus detection areas are set in the row direction and three in the column direction. However, the number, position, and size of the focus detection area may be set as appropriate. For example, in the imaging device that can obtain the first focus detection signal and the second focus detection signal from any pixel in the effective pixel region 400 like the imaging device 122 described above, a predetermined range centering on the region designated by the photographer. May be set as the focus detection area.

[First focus detection]
Hereinafter, the first focus detection of the imaging surface phase difference method in the first embodiment will be described. In the first focus detection of the imaging surface phase difference method, the first focus detection signal and the second focus detection signal are relatively shifted to calculate a correlation amount (hereinafter referred to as a first evaluation value) representing the degree of coincidence of the signals, The image shift amount is detected from the shift amount that improves the correlation (signal coincidence). As the magnitude of the defocus amount of the recorded image signal increases, the image deviation amount is first detected from the relationship that the magnitude of the image deviation amount between the first focus detection signal and the second focus detection signal increases. The focus is detected by converting to a defocus amount.

  FIG. 5 shows a flowchart of the first focus detection process in the first embodiment. The processing in FIG. 5 is executed by the focus detection signal generation unit, the imaging element 122 as the first focus detection unit, the imaging plane phase difference focus detection unit 126, and the camera MPU 124 in the first embodiment.

  In S510, a focus detection area is set in the effective pixel area 400 of the image sensor 122. A focus detection signal generation unit generates a first focus detection signal (A image signal) from the light reception signal of the first photoelectric conversion unit 201 in the focus detection region, and the second photoelectric conversion unit 202 in the focus detection region. A second focus detection signal (B image signal) is generated from the received light signal.

  In S520, for each of the first focus detection signal (A image signal) and the second focus detection signal (B image signal), a three-pixel addition process is performed in the column direction in order to reduce the amount of signal data. A Bayer (RGB) addition process is performed to convert the RGB signal into a luminance Y signal. These two addition processes are combined into a first pixel addition process.

  In S530, a shading correction process (optical correction process) is performed on each of the first focus detection signal and the second focus detection signal subjected to the first pixel addition process. Hereinafter, shading due to pupil shift between the first focus detection signal and the second focus detection signal will be described. FIG. 6 shows the first pupil partial region 601 of the first photoelectric conversion unit 201, the second pupil partial region 602 of the second photoelectric conversion unit 202, and the exit pupil of the imaging optical system at the peripheral image height of the image sensor 122. 600 relationships are shown.

  FIG. 6A shows a case where the exit pupil distance Dl of the imaging optical system and the set pupil distance Ds of the image sensor 122 are the same. In this case, the exit pupil 600 of the imaging optical system is substantially equally divided by the first pupil partial region 601 and the second pupil partial region 602.

  On the other hand, when the exit pupil distance Dl of the imaging optical system shown in FIG. 6B is shorter than the set pupil distance Ds of the image sensor 122, the exit of the imaging optical system is performed at the peripheral image height of the image sensor 122. A pupil shift occurs between the pupil and the entrance pupil of the image sensor 122. For this reason, the exit pupil 600 of the imaging optical system is non-uniformly divided into pupils. Similarly, when the exit pupil distance Dl of the imaging optical system shown in FIG. 9C is longer than the set pupil distance Ds of the imaging device, the imaging pupil and the exit pupil of the imaging optical system are imaged at the peripheral image height of the imaging device 122. A pupil shift of the entrance pupil of the element 122 occurs, and the exit pupil 600 of the imaging optical system is non-uniformly pupil-divided. As pupil division becomes nonuniform at the peripheral image height, the intensity of the first focus detection signal and the second focus detection signal also becomes nonuniform, and one of the first focus detection signal and the second focus detection signal Shading occurs with increasing strength and decreasing the other strength.

  Therefore, in S530, first, according to the image height of the focus detection area, the F value of the lens unit (imaging optical system), and the exit pupil distance, the first shading correction coefficient of the first focus detection signal, the second A second shading correction coefficient for the focus detection signal is generated. Then, the first focus detection signal is multiplied by the first focus detection signal, the second shading correction coefficient is multiplied by the second focus detection signal, and shading correction processing (optical) of the first focus detection signal and the second focus detection signal is performed. Correction process).

  In the first focus detection of the imaging surface phase difference method, the first detection defocus amount is detected based on the correlation (the degree of coincidence of signals) between the first focus detection signal and the second focus detection signal. When shading due to pupil shift occurs, the correlation between the first focus detection signal and the second focus detection signal may decrease. Therefore, in the first focus detection of the imaging plane phase difference method, it is desirable to perform shading correction processing in order to improve the correlation between the first focus detection signal and the second focus detection signal and to improve the focus detection performance.

  In S540, the first filter processing is performed on the first focus detection signal and the second focus detection signal subjected to the shading correction processing. An example of a pass band of the first filter process of the first embodiment is indicated by a solid line 701 in FIG. In Embodiment 1, since the focus detection in the large defocus state is performed by the first focus detection of the imaging surface phase difference method, the pass band of the first filter processing is configured to include the low frequency band. When the focus adjustment is performed from the large defocus state to the small defocus state as necessary, the pass band of the first filter processing at the time of the first focus detection according to the defocus state is indicated by a one-dot chain line in FIG. In this way, the frequency may be adjusted to a higher frequency band.

  Next, in S550, a first shift process is performed in which the first focus detection signal and the second focus detection signal after the first filter process are relatively shifted in the pupil division direction, and a correlation amount (a first amount indicating the degree of coincidence of the signals) 1 evaluation value) is calculated.

  The k-th first focus detection signal after the first filter processing is A (k), the second focus detection signal is B (k), and the range of the number k corresponding to the focus detection area is W. Further, assuming that the shift amount by the first shift process is s1 and the shift range of the shift amount s1 is Γ1, the correlation amount (first evaluation value) COR is calculated by Expression (1).

  By the first shift process of the shift amount s1, the k-th first focus detection signal A (k) and the k-s1st second focus detection signal B (k-s1) are subtracted in correspondence to generate a shift subtraction signal. To do. The absolute value of the generated shift subtraction signal is calculated, the number k is summed within the range W corresponding to the focus detection area, and the correlation amount (first evaluation value) COR (s1) is calculated. If necessary, the correlation amount (first evaluation value) calculated for each row may be added over a plurality of rows for each shift amount.

  In S560, a real-valued shift amount at which the correlation amount is the minimum value is calculated from the correlation amount (first evaluation value) by subpixel calculation, and is set as the image shift amount p1. Then, the first detection defocus is obtained by multiplying the calculated image shift amount p1 by the image height of the focus detection region, the F value of the lens unit (imaging optical system), and the first conversion coefficient K1 corresponding to the exit pupil distance. The amount (Def1) is detected.

  Here, the first conversion coefficient K1 will be described. As shown in FIGS. 6B and 6C, as the pupil division becomes nonuniform at the peripheral image height, the intensities of the first focus detection signal and the second focus detection signal also become nonuniform. The intensity of one of the detection signal and the second focus detection signal is increased, and the intensity of the other is decreased. Further, when the exit pupil distance Dl is longer (or shorter) than the set pupil distance Ds of the image sensor, a pupil shift occurs between the exit pupil of the imaging optical system and the entrance pupil of the image sensor at the peripheral image height of the image sensor. This is because the exit pupil 600 of the image optical system is non-uniformly divided into pupils. From this, as described above, the intensity of one of the first focus detection signal and the second focus detection signal is increased, and the intensity of the other is decreased. In addition, since the size of the exit pupil 600 also changes depending on the F value, the pupil division of the exit pupil 600 of the imaging optical system becomes non-uniform also depending on the F value. When the pupil division becomes non-uniform, the center-of-gravity distance between the first focus detection signal and the second focus detection signal changes, so the first conversion coefficient K1 that is a defocus conversion coefficient changes. Therefore, the first conversion coefficient K1 is a coefficient that varies depending on the exit pupil distance Dl, the image height, and the F value. The first conversion coefficient K1 may be calculated from the exit pupil distance D1, image height, and F value at that time, or may be a coefficient obtained from a table using the exit pupil distance D1, image height, and F value. .

  In the imaging device 122 of this embodiment, the light beam received by the first photoelectric conversion unit and the second photoelectric conversion unit is different from the light beam received by the entire pixel unit, and each aberration (spherical aberration, non-spherical aberration) of the imaging optical system is different. The influence on the focus detection pixel and the influence on the recorded image signal are different. The difference becomes larger when the aperture value of the imaging optical system is small and the aperture is large (the subject is dark). Therefore, when the aperture value of the imaging optical system is small and the aperture is large, the detection defocus amount calculated by the first focus detection of the imaging plane phase difference method and the defocusing based on, for example, the MTF peak position of the recorded image signal, etc. There may be a difference between the focus amount. In particular, when the aperture value of the imaging optical system is equal to or smaller than a predetermined aperture value, the focus detection accuracy of the first focus detection of the imaging surface phase difference method may be lowered.

  FIG. 8 illustrates an example of the first focus detection signal (broken line) and the second focus detection signal (solid line) at the peripheral image height of the image sensor 107 according to the first embodiment when the focus lens 103 is in focus. Show. Here, although the focus lens 103 is in a focused position, an example is shown in which the signal shapes of the first focus detection signal and the second focus detection signal are different due to the influence of each aberration of the imaging optical system. FIG. 9 shows the first focus detection signal (broken line) and the second focus detection signal (solid line) at the peripheral image height after the shading correction process and the first filter process when the focus lens 103 is also in focus. Indicates. Although the focus lens 103 is in focus, the image shift amount p1 between the first focus detection signal and the second focus detection signal is not zero. As a result, there is a difference between the defocus amount calculated by the first focus detection of the imaging surface phase difference method and the defocus amount based on the MTF peak position or the like.

  FIG. 10 illustrates an example of the first detected defocus amount (broken line) obtained by the first focus detection of the imaging surface phase difference method in the first embodiment. The horizontal axis represents the set defocus amount with the defocus amount of 0 [mm] in an ideal situation where there is no difference as described above. The vertical axis represents the detection defocus amount actually obtained by focus detection using the imaging surface phase difference method. The first focus detection signal and the second focus detection signal shown in FIG. 8 are the first focus detection signal and the second focus detection signal at the set defocus amount 0 [mm] in FIG. If there is no error between the detected defocus amount and the set defocus amount, a straight line as shown by a two-dot chain point is drawn. When the set defocus amount is 0 [mm], since the first detection defocus amount is offset by about 50 μm to the rear pin side, the defocus amount to be focused and the detection defocus calculated by the first focus detection It can be seen that there is a difference of about 50 um between the quantity.

  For this reason, in this embodiment, a defocus amount correction (hereinafter referred to as “best focus correction”) (S1412) according to the state of the imaging optical system is performed. Details will be described later.

[Refocus image generation processing]
In the present embodiment, a refocus image is generated using signals from the first photoelectric conversion unit 201 and the second photoelectric conversion unit 202 included in the recorded image. As described above, the refocus image is an image corresponding to an image on a virtual imaging plane different from the current imaging plane. That is, the refocus image is an image corresponding to an image that can be acquired when it is assumed that the focus lens 103 is at a different position. The generation of such an image is hereinafter referred to as refocusing.

  In order to perform refocusing, the signal acquired from the first photoelectric conversion unit 201 and the signal acquired from the second photoelectric conversion unit in accordance with the pixel arrangement on the virtual imaging plane are converted into the image processing circuit 125 (generation unit). ) Are relatively shifted and added. Hereinafter, a process for generating a refocus image will be described in detail.

  In FIG. 12, i is an integer, Ai is a signal acquired by the first photoelectric conversion unit 201 included in the i-th pixel unit in the column direction of the image sensor 122 arranged on the imaging surface 1210, and the second pixel is included in the same pixel unit. A signal acquired by the photoelectric conversion unit 202 is schematically represented as Bi.

  The signal Ai and the signal Bi have not only light intensity distribution information but also incident angle information. Therefore, the signal Ai is translated along the angle θa to the virtual imaging plane 1220, and the signal Bi is translated along the angle θb to the virtual imaging plane 1220, and added to the corresponding signals. As a result, a refocus signal for generating a refocus image on the virtual imaging plane 1220 can be generated. Translating the signal Ai along the angle θa to the virtual imaging plane 1220 corresponds to shifting +0.5 pixels in the column direction. Further, translating the signal Bi along the angle θb to the virtual imaging plane 1220 corresponds to shifting −0.5 pixels in the column direction. Therefore, the refocusing signal on the virtual imaging plane 1220 can be generated by relatively shifting the signal Ai and the signal Bi by +1 pixel and adding Ai and Bi + 1 corresponding to each other. Similarly, by shifting the signal Ai and the signal Bi by an integer pixel and adding them, a shift addition signal (refocus signal) on each virtual imaging plane can be generated according to the integer shift amount. A refocus image can be generated by using a plurality of refocus signals as described above.

[Refocusable range]
However, there is a limit to the refocusable range. FIG. 13 is an explanatory diagram of the refocusable range in the first embodiment. If the allowable circle of confusion is δ and the aperture value of the imaging optical system is F, the depth of field at the aperture value F is ± Fδ. On the other hand, the effective aperture value F ₀₁ (or F ₀₂ ) in the horizontal direction of the pupil partial region 1311 (or 1312) narrowed by dividing N _H × N _V (2 × 1) is F ₀₁ = N _H It becomes dark with F. The effective depth of field for each first focus detection signal (or second focus detection signal) becomes _NH Fδ and N _H times deeper, and the focus range is extended N _H times. Within the range of effective depth of field ± N _H Fδ, a focused subject image is acquired for each first focus detection signal (or second focus detection signal). Therefore, the focus position is readjusted (re-adjusted) after photographing by the refocus process of translating the first focus detection signal (or second focus detection signal) along the chief ray angle θa (or θb) shown in FIG. Focus). Therefore, the defocus amount d from the imaging surface that can be refocused after shooting is limited, and the refocusable range of the defocus amount d is approximately the range of Expression (2).

  The permissible circle of confusion δ is defined by δ = 2ΔX (the reciprocal of the Nyquist frequency 1 / (2ΔX) of the pixel period ΔX).

  Regarding the principle of refocusing, the item “Refocusing Image Generation Processing” in Japanese Patent Application Laid-Open No. 2014-64214 is detailed.

[Focus position adjustment value setting]
In the digital camera 120 of this embodiment, when the user adjusts the focus state to a desired state, the EEPROM 124a (storage means) stores an adjustment value corresponding to the state. Then, the AF operation can be controlled so that this adjustment value is reflected at the time of focus adjustment associated with subsequent shooting.

  With reference to FIG. 14, an operation for setting an adjustment value for adjusting the focal position executed by the camera MPU 124 will be described. In FIG. 14, S is an abbreviation for a step.

  FIG. 14 is a flowchart of the operation of setting the focus position adjustment value of the digital camera 120, which is executed by the camera MPU 124, and is stored in the ROM 124c.

[Focus detection (first focus detection)]
The camera MPU 124 determines whether an AF operation has been performed by the user operating the SW 128 (S1410). If the predetermined time has elapsed without performing the AF operation, or if the operation for stopping the focus position adjustment value setting is performed by the operation of the SW 128, the camera MPU 124 ends the focus position adjustment value setting (S1490). On the other hand, when the AF operation is performed, the camera MPU 124 reads the first focus detection signal and the second focus detection signal from the image sensor driving circuit 123. The imaging plane phase difference focus detection unit 126 (focus detection means) calculates a relative displacement amount by performing a correlation operation using the two read signals. Further, the imaging plane phase difference focus detection unit 126 performs first focus detection (described above) that is converted into a defocus amount by multiplying by the first conversion coefficient K1 (S1411).

[Best focus correction]
Next, the above-described best focus correction (correction of the defocus amount in accordance with the state of the imaging optical system) is performed on the defocus amount calculated by the first focus detection (S1412). Hereinafter, the best focus correction will be described. Although a more accurate defocus amount can be obtained by the best focus correction, priority may be given to reducing the processing load of the camera MPU 124, and the best focus correction may be omitted.

  FIG. 11 shows an example of the best focus correction value stored in the EEPROM 124a. FIG. 11 shows the best focus correction value corresponding to the focus detection area A (2, 2) in FIG. Similarly, the best focus correction values are stored for the other eight focus detection areas. However, the design best focus correction value is the same for a focus detection region that is symmetrical with respect to the optical axis of the imaging optical system. Accordingly, it is only necessary to store four best focus correction value tables for nine focus detection areas.

  In FIG. 11, the zoom position and the focus position of the imaging optical system are divided into eight zones, and the best focus correction values BP111 to BP188 are provided for each of the divided zones. Accordingly, the best focus correction value with high accuracy can be obtained according to the positions of the second lens group 102 and the first lens group 101 of the imaging optical system.

  In the first embodiment, the best focus correction value is stored in the table data for each focus detection area as shown in FIG. 11, but the method for storing the best focus correction value is not limited to this. For example, coordinates are set with the intersection of the optical axis of the imaging device and the imaging optical system as the origin and the horizontal and vertical directions of the imaging device as the X axis and the Y axis, and the correction value at the center coordinate of the focus detection area is set as X You may obtain | require with the function of Y. In this case, the amount of information to be stored as the best focus correction value can be reduced.

[Focus driving to photographing (S1413 to S1415)]
The camera MPU 124 controls the focus actuator 110 (focus adjustment unit) to drive the focus lens 103 to perform focusing based on the defocus amount corrected by the best focus correction (S1413).

  When the AF operation is completed by focusing driving, the camera MPU 124 notifies the user that the AF operation on the subject is completed. Thereafter, it is determined whether or not the user has performed a release operation (S1414). If the predetermined time has elapsed without performing the release operation, the process returns to S1410. On the other hand, when the release operation is performed, the camera MPU 124 performs photographing (S1415).

[Selection / Setting of Focus Position Adjustment Value (S1416 to S1427)]
The camera MPU 124 displays the photographed recorded image on the display unit 127, and causes the user to select whether to set the focus position adjustment value based on the image, YES or NO (S1416). If the user selects NO, the process returns to S1410. On the other hand, when the user selects YES, the camera MPU 124 performs refocusing (described above) by the image processing circuit 125 (generation unit), and creates a plurality of focus bracket images (in the first embodiment, five as an example). (S1417). The focus bracket image is an image with different focal positions. Specifically, one image with a signal shift amount of 0, one image at the most infinite distance and one image at the closest distance within the refocusable range, and an image with an intermediate defocus amount. Create one each.

  The camera MPU 124 determines whether a refocus image can be created again (S1418). Specifically, it is determined whether or not the signal shift amount is zero when the focus bracket is created by the next refocus. If a refocus image can be created again, the user is notified that up to two images are to be selected (S1419). If the refocus image cannot be created again, the user is notified that one image is to be selected (S1420).

  The camera MPU 124 determines whether the user has performed a focus bracket image selection operation (S1421). If a predetermined time has elapsed without any operation being performed, or if an operation for canceling the setting has been performed, the process returns to S1410. When a plurality of images are selected by the user (S1422), the camera MPU 124 creates five focus bracket images again by the image processing circuit 125 (generation unit) within the defocus range of the two selected images. Control as follows. Then, the process returns to S1418 (S1423). For example, when an image with a signal shift amount of 0 and an image with an intermediate defocus amount at infinity are selected, an image with a signal shift amount of 0 and an intermediate defocus at infinity Five refocus images are created between the defocus amounts of the images. When there is one selected image, the camera MPU 124 acquires the pixel shift amount from the selected image by the image processing circuit 125 (S1424).

  The camera MPU 124 calculates a defocus amount for acquiring the selected image from the acquired pixel shift amount (S1425).

  The camera MPU 124 converts the defocus amount of the selected image calculated in S1425 into a focus position adjustment value (a focus position adjustment value, also simply referred to as an adjustment value) (S1426), and stores it in the EEPROM 124a (storage means). Store (S1427). The focus position adjustment value can be stored for each lens unit.

  In this embodiment, when the focus position adjustment value is stored in the EEPROM 124a (storage means), the defocus amount calculated by the imaging plane phase difference AF using the focus position adjustment value by the camera MPU 124 (adjustment means). Adjust. The correction timing may be any time after the first focus detection in S1411 and before the driving of the focus lens in S1413. The EEPROM 124a (storage means) stores a focus position adjustment value for each lens unit to be used. Further, the focus position adjustment value is stored for each zoom position of the lens in the EEPROM 124a (storage means), and the camera MPU 124 (adjustment means) adjusts the defocus amount for each zoom position of the lens unit.

[Effect of Example 1]
In the conventional method, in order to create a focus bracket image from S1416 to S1417, it is necessary to continuously shoot while actually moving the focus position. A time difference occurs. When the time difference occurs, for example, when the subject moves, the positions of the subjects do not match in the plurality of images to be acquired. In such a case, it becomes difficult to select the adjustment value accurately.

  On the other hand, according to the first embodiment, the focus bracket image is created not by continuous shooting but by refocusing. Since it is possible to generate a plurality of refocused images by refocusing based on a recorded image obtained by one shooting, there is no time difference between the plurality of images. From this, the adjustment value can be selected more accurately. In the conventional method, the camera sometimes moves finely for each shooting during continuous shooting. On the other hand, in Example 1, since the number of times of photographing for acquiring a plurality of images can be reduced, the camera is difficult to move.

  Further, in the conventional method, when the focal position to be adjusted is a position between the focal positions of the actually acquired focus bracket images, it is necessary to perform imaging again. On the other hand, in the first embodiment, since refocusing can be performed again in a different range based on an image acquired once without performing imaging again, it is possible to save time and effort for the user.

  Further, according to the first embodiment, it is possible to reduce the number of times of photographing necessary for creating a plurality of images. As a result, the time required for shooting can be shortened.

  In the first embodiment, it is possible not only to generate a refocus image but also to obtain a further effect by storing and using the adjustment value. By simply generating a refocus image, the user adjusts the focus state each time, or obtains multiple focus state images, and selects an image that reflects the focus state preferable for the user each time. There is a need. On the other hand, it is possible not only to generate a refocus image but also to store the adjustment value and use it to reflect the user's favorite focus state in the next and subsequent shootings. Thereby, compared with the case where a refocus image is simply generated, it is possible to save time and effort of the user.

  As described above, according to the first embodiment, it is possible to save the time and effort of the user and improve the usability of the camera for the user.

[Example 2]
Next, with reference to FIG. 15, the second embodiment will be described focusing on differences from the first embodiment.

  In the first embodiment, it has been described that the image used for refocusing is taken once in the focus position adjustment value setting (flow in FIG. 14). In the second embodiment, a plurality of images used for refocus are photographed with different focus positions.

[Focus position adjustment setting]
The focus position adjustment setting of the second embodiment is different from the first embodiment in that S1515 and S1516 are increased between S1415 and S1416 of the focus position adjustment setting (FIG. 14) of the first embodiment.

  The camera MPU 124 moves the focal position by a predetermined amount from the current focus position to the close side, and performs photographing (S1516). The predetermined amount here may be a fixed value, or the lens driving amount M using the reciprocal of the first conversion coefficient K1 may be obtained. Optimal lens for generating a refocused image shifted by an ideal defocus amount by using the reciprocal of the first conversion coefficient K1 (for example, displaying like a bracketed image captured at equal intervals). The driving amount M can be calculated.

  The camera MPU 124 moves the focus position by a predetermined amount from the current focus position to the ∞ distance side and performs shooting (S1517). The predetermined amount here may be a fixed value or the lens driving amount M described above.

  In this embodiment, the focus position is in focus, and shooting is performed three times on the close side and the infinite side. However, the present invention is not limited to this.

  The camera MPU 124 displays a plurality of captured images on the display unit 127, and allows the user to select from which image the focus position adjustment value is set (S1518). If the predetermined time elapses without operation or the user selects NO, the process returns to S1510. On the other hand, when the user selects any image, the camera MPU 124 creates five focus bracket images from the selected image by the image processing circuit 125 (S1519). Specifically, one image with a signal shift amount of 0, one image at the most infinite distance and one image at the closest distance within the refocusable range, and an image with an intermediate defocus amount. Create one each.

  Here, the shift amount of the refocus image is determined according to the refocusable range, but the pixel shift amount may be determined using the reciprocal of the first conversion coefficient K1. By using the first conversion coefficient K1, it is possible to display an image shifted by an ideal defocus amount (for example, a constant defocus amount as in focus bracket photography).

[Effect of Example 2]
In this embodiment, in order to acquire an image for refocusing, shooting is performed a plurality of times with different focus positions. Therefore, after the user roughly selects a suitable focus position, a focus bracket image by refocusing is displayed. You can choose. According to the present embodiment, it is possible to acquire a focus bracket image for a wider focus range than when shooting is performed only once. From this, when the focus position of a single shooting result and the desired focus position deviate beyond the refocusable range, it is possible to reduce the trouble of performing the shooting again. Usability is improved.

[Example 3]
Next, an example according to Example 3 will be described. In the first and second embodiments, the example in which the focus detection (first focus detection) is performed using the imaging surface phase difference AF has been described. On the other hand, in Example 3, focus detection (second focus detection described later) is performed using a defocus detection unit 134 that is a photoelectric conversion element for AF. The third embodiment will be described with a focus on differences from the first and second embodiments.

[Configuration of phase difference AF]
When focus detection is performed using the defocus detection unit 134, the defocus amount necessary for focus adjustment is calculated based on the output from the defocus amount detection unit 134. Specifically, it is calculated from the relative displacement amounts of two images formed from light beams that have passed through two different pupil regions of the lens unit 100. The light beams of these two images pass through the main mirror 131 that is a half mirror, are reflected by the sub mirror 132 behind the main mirror 131, and are guided to the defocus amount detection unit 134 by a focus detection optical system (not shown).

  The defocus amount detection unit 134 (AF element) is a photoelectric conversion element having a line sensor, and outputs a subject image formed on the element as a potential change. The camera MPU 124 reads the signals of these two images, calculates a relative displacement amount by performing a correlation calculation on the signals, and multiplies the specific coefficient to convert it into a defocus amount (Def2) (hereinafter referred to as a second focus detection). The details will be described later).

  Although the defocus amount can be obtained in this way, the defocus amount cannot always be detected for every subject. Specifically, if the contrast of the subject image signal is small, the S / N ratio of the line sensor is also low, and the accuracy of the detection result is lower than when the contrast is high. In addition, when a ghost occurs in the focus detection optical system under backlighting or the like, the degree of coincidence between the two images is lowered, so that an accurate image shift amount cannot be calculated by correlation calculation. Therefore, a predetermined threshold is provided for the contrast of the subject image signal and the degree of coincidence of the two images, and the focus detection is disabled when the threshold is below the threshold. Also, due to the tolerance of the focus detection system, even if there is a subject at a defocus amount of 0 by design, the focus is not always 0 for all cameras.

  Therefore, in the calibration process of the factory, the parameters of the EEPROM 124a are written and adjusted so that the defocus amount becomes 0 when the image pickup device 122 is in focus. Specifically, first, the amount of deviation from the design value is obtained by measuring the flange back of the camera (the distance from the lens unit to the image sensor 122). Next, a reference lens that has been previously focused on a reference subject at a known distance is corrected by the amount of deviation of the flange back. Next, the defocus amount of the reference subject is measured. Subsequently, the adjustment value is written in the EEPROM 124a so that the measured defocus amount becomes zero. At the time of shooting, the camera MPU 124 sets the defocus amount calculated by adding the adjustment value written in the EEPROM 124 a to the defocus amount calculated from the output of the defocus amount detection unit 134.

  This enables automatic focus detection that absorbs individual differences between cameras.

  This correction value is individually adjusted for each focus area and written to the EEPROM 124a.

  The best focus correction (described above) is further added to the defocus amount thus converted. As described above, the best focus correction is a correction for a deviation amount between the focus of the subject light beam at the time of photographing and the focus of the subject light beam by the focus detection optical system. This shift amount is caused by a shift in spectral sensitivity between the image sensor 122 and the defocus amount detection unit 134 and spherical aberration of the lens unit 100. That is, the lens unit has different values for each focus area for detecting the defocus amount, the distance ring position of the lens unit 100, and the zoom position.

  This best focus adjustment value is stored in the lens MPU 112 of the attached lens 100. Therefore, the lens MPU 112 reads the current distance ring position and zoom position from the distance ring position detection unit 10 and the zoom position detection unit 114, and transmits the corresponding best focus adjustment value to the camera MPU 124 by communication. The camera MPU 124 can perform optimum focus adjustment for each lens unit by adding the best focus adjustment value to the defocus amount as a new defocus amount. If the defocus amount in this embodiment is positive, it is defined as a focus shift that requires the distance ring to move in the closest direction.

[Second focus detection]
Next, a series of second focus detection processes according to the third embodiment will be described with reference to the flowchart of FIG. 17 using FIG.

  The focus detection is started from FIG. 17, and accumulation is started for each of the vertical direction and the horizontal direction in S1710. Then, in S1720 or S1730, each storage completion is awaited. When the accumulation is completed, the process proceeds to S1721 or S1731, and image signal reading, calculation, and reliability determination of the focus detection result are performed, and correction of the defocus amount deviation in the vertical and horizontal directions (described later) is performed.

  In the next S1740, the camera MPU 124 determines whether vertical and horizontal focus detection has been completed. If focus detection has not been completed, the process returns to S1720. When focus detection is completed in both the vertical and horizontal directions, the process proceeds to S1750, and it is determined whether or not the defocus amount detection in both the vertical and horizontal directions is successful. If the defocus amount detection is successful in both the vertical and horizontal directions, the process proceeds to S1760. If unsuccessful, the process advances to step S1770.

  In S1740, as shown in FIG. 16, the detection result for the past 100 times is used as an upper limit, and the lens unit, the focus area position, the distance ring position, and the zoom position that are currently mounted are associated with each other. Then, the vertical and horizontal defocus amounts are stored in the EEPROM 124a as a focus detection history. At the same time, from the focus detection history stored in the EEPROM 124a, the average value of the difference between the defocus amounts in the vertical direction and the horizontal direction corresponding to the currently mounted lens unit, focus area position, distance ring position, and zoom position is calculated. Ask. When the detection result exceeding 100 times is obtained, the latest detection result is overwritten on the oldest detection result. Therefore, there is a possibility that the average value of the difference is updated at every distance measurement.

  When the focus detection history for 100 times is obtained, the average value of the differences becomes a correction value for the defocus amount deviation in the vertical and horizontal directions in either S1721 or S1731. That is, in the latest defocus amount detection, as a result of taking the average of the difference in the vertical and horizontal directions of the past defocus amount, the average value of this difference is corrected to the defocus amount in the direction in which the focus position indicates the rear side. Added as. The defocus amount in the other direction is not corrected. Specifically, the average value of the difference in defocus amount from the vertical direction to the horizontal direction is taken. If the average value is positive, the defocus amount in the horizontal direction is on the rear side on the average according to the definition of the defocus amount described above, so the average value of this difference is added to the front side. There is no difference between the defocus amount in the vertical direction and the average value.

  Conversely, if the average value of the differences is taken and the average value is negative, the defocus amount in the vertical direction is on the rear side on average, so by subtracting the average value of this difference, There is no difference between the direction defocus amount and the average value.

  After a series of these processes, if the detection of the defocus amount in both the vertical and horizontal directions is successful in the next S1770 (YES in S1750), the defocus amount in the direction that is finally closer and in the direction that indicates a larger value. Is selected as the latest detection result. This is because a slight difference may occur even in the corrected defocus amounts in both the vertical and horizontal directions, so the closest defocus amount is selected. The selected defocus amount is subject to correction by setting the focus position adjustment value.

  If the defocus amount detection in only one direction is successful and the process proceeds from S1750 to S1710, the defocus amount is selected as the latest distance measurement result.

  Also, when the detection of the defocus amount in both the vertical and horizontal directions fails, the process proceeds from S1750 to S1770, and here, the latest detection result is determined to be a failure.

[Focus position adjustment value setting]
As described above, the digital camera 120 according to the third embodiment is different from the first embodiment in that focus detection is performed using the defocus detection unit 134 instead of the imaging surface phase difference AF using the imaging element 122.

  FIG. 18 corresponds to the focus position adjustment value setting (FIG. 14) of the first embodiment. In S1811, the second focus detection (described above) is performed instead of the first focus detection in S1411 of FIG.

  FIG. 19 corresponds to the focus position adjustment value setting (FIG. 15) of the second embodiment. In S1911, the second focus detection (described above) is performed instead of the first focus detection in S1511 of FIG.

[Effect of Example 3]
In the third embodiment, focus detection is performed using the defocus detection unit 134 instead of the imaging surface phase difference AF using the imaging device of the first or second embodiment. Therefore, the first or second embodiment is used. The same effect can be obtained.

[Other Examples]
The case where a plurality of images are generated from the refocus image has been described. However, a refocus image in which the focal position is changed may be generated in real time according to a user operation. In this case, instead of generating a plurality of images at a time and presenting them to the user, it is possible to specify the focus position and set the adjustment value by the user's intuitive operation. With this configuration, for example, S1416 to S1423 in the first embodiment can be replaced with the operation of the focal position by the user. That is, it is possible to reduce the time for the user to operate the camera and reduce the trouble of operating the camera. In addition, since the user can confirm the focal position in real time, the focal position can be adjusted according to the user's preference. Thereby, it is possible to obtain an adjustment value for acquiring an image more in line with the user's preference.

  In addition, the configuration for changing the focal position after shooting is not necessarily the configuration shown in the first and second embodiments. For example, the configuration disclosed in the prior art (for example, JP2013-201752A) may be used.

  In the above-described embodiment, the adjustment value is described as the defocus amount adjustment value, but may be the lens drive amount adjustment value. For example, it is possible to store, as an adjustment value, a lens driving amount that indicates how many pulses the lens is driven with respect to a lens driving amount derived from a defocus amount detected by focus detection. In this case, the adjustment value is stored in consideration of the lens unit itself, the image height for focus detection, the sensitivity of lens driving depending on the focus position of the subject, and the like. Since the appropriate adjustment value varies depending on the zoom position, the lens drive amount can be adjusted more accurately by storing the adjustment value for each zoom position.

  In the above-described embodiments, the interchangeable lens single-lens reflex camera has been described. However, the present invention is also applicable to an optical apparatus having an imaging device such as a bidet camera and other focus adjustment devices.

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

103 Third lens group (focus lens)
110 Focus actuator 122 Image sensor 124 Camera MPU
124a EEPROM
125 Image Processing Circuit 126 Imaging Surface Phase Difference Focus Detection Unit 134 Defocus Amount Detection Unit (AF Element)

Claims (13)

An image sensor having a plurality of pixel units each having a plurality of photoelectric conversion units that receive and photoelectrically convert light beams that have passed through different pupil regions of the optical system;
Focus detection means for detecting a defocus amount;
Focus adjusting means for driving the focus lens based on the defocus amount and adjusting the focus position;
Generation means for generating a plurality of refocus images using signals obtained from the plurality of photoelectric conversion units and having different focal positions ;
Storage means for storing an adjustment value for adjusting the focal position corresponding to the refocus image generated by the generation means;
The imaging apparatus, wherein the focus adjustment unit adjusts a focus position based on the adjustment value stored in the storage unit. The adjustment value is a defocus amount adjustment value,
The imaging apparatus according to claim 1, wherein the focus adjustment unit performs focus adjustment based on the defocus amount and the adjustment value detected by the focus detection unit.   The adjustment value is a value based on the defocus amount detected by the focus detection unit and a defocus amount corresponding to the refocus image in which the storage unit stores the adjustment value. Imaging device. The adjustment value is an adjustment value of the driving amount of the focus lens,
The imaging apparatus according to claim 1, wherein the focus adjustment unit drives the focus lens by a lens drive amount reflecting the adjustment value. The refocus image is an image corresponding to an image on a virtual imaging plane different from the current imaging plane;
The plurality of photoelectric conversion units are a first photoelectric conversion unit and a second photoelectric conversion unit,
The generation means is a signal obtained by adding a signal acquired from the first photoelectric conversion unit and a signal acquired from a second photoelectric conversion unit of a pixel unit different from the pixel unit having the first photoelectric conversion unit. 5. The imaging apparatus according to claim 1, wherein the refocus image is generated using a plurality of signals corresponding to. The generating means generates a plurality of refocus images having different focal positions;
The focus adjustment unit adjusts a focus position based on an adjustment value corresponding to an image selected by a user among the plurality of refocus images. The imaging device described. Display means for displaying the refocus image generated by the generation means;
7. The focus adjustment unit adjusts a focal position based on an adjustment value corresponding to a refocus image selected by a user among refocus images displayed by the display unit. The imaging device according to any one of the above. Among the plurality of refocusing image said generating means has generated, if the user has multiple refocus images have been selected, said generating means in the range of focus positions of the refocused image, again, a plurality of Li The imaging apparatus according to claim 1, wherein a focus image is generated.   The imaging apparatus according to claim 5, wherein the focus detection unit detects a defocus amount using signals acquired from the first photoelectric conversion unit and the second photoelectric conversion unit. An AF element having a line sensor;
The image pickup apparatus according to claim 1, wherein the focus detection unit detects a defocus amount using a signal acquired from the AF element. In a control method for an imaging apparatus having a plurality of pixel units each having a plurality of photoelectric conversion units that receive and photoelectrically convert light beams that have passed through different pupil regions of the optical system,
A focus detection step for detecting a defocus amount;
A focus adjustment step of driving a focus lens based on the defocus amount and adjusting a focus position;
A generation step of generating a plurality of refocus images using signals obtained from the plurality of photoelectric conversion units and having different focal positions ;
A storage step for storing an adjustment value for adjusting the focal position corresponding to the refocus image generated in the generation step;
Adjusting the defocus amount using the adjustment value, and
In the focus adjustment step, the focus position is adjusted based on the adjustment value stored in the storage step.   A program for causing a computer to execute each step in the control method according to claim 11.   A storage medium for storing the program according to claim 12 so as to be read by a computer.

Images