JP2014130231A - Imaging apparatus, method for controlling the same, and control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an accurately focused image with a short release time lag, when performing photographing from a live view state.SOLUTION: An AF unit 202 receives an optical image and outputs a focus state detection result for indicating whether or not the optical image is in a focused state. A CPU 121 selects a first state where the optical image from a photographic lens 137 is guided to an imaging element 107 and a second state where the optical image is guided to the AF unit and obtains the first state, to start the exposure of the imaging element and then, obtains the second state, to correct the blur of a photographed image, based on the focus state detection result, when photographing instruction is issued.

Description

  The present invention relates to an imaging apparatus having a function of repairing blurring of an image obtained as a result of photographing, a control method thereof, and a control program.

  In recent years, in an imaging apparatus such as a digital single-lens reflex camera, so-called live view shooting is performed in which shooting is performed while viewing a video (image) displayed on a liquid crystal panel disposed on the back of a housing. In general, when focus adjustment is performed during live view shooting, contrast detection is performed using an image signal obtained from an image sensor such as a CMOS image sensor.

  On the other hand, blur restoration is performed on a blur image that is out of focus using a blur restoration filter such as a Wiener filter, a general inverse filter, or a projection filter. For example, a deteriorating function is obtained by an image restoration algorithm called deconvolution by obtaining a degradation function by physical analysis based on imaging conditions or by estimation based on an output from a measurement apparatus provided in the imaging apparatus. (See Patent Document 1).

JP 2000-20691 A

  By the way, when taking a still image from the live view state, it takes a long time to adjust the focus by detecting the contrast when taking a picture after the focusing operation is completed. May not be possible. On the other hand, if an attempt is made to obtain a still image at the moment intended by the photographer, a still image that is not in focus may be obtained.

  Then, if an attempt is made to restore a blur using a filter as described in Patent Document 1 for a still image that is not in focus, a huge amount of computation is required to obtain an optimum filter for performing the restoration of the blur. Therefore, it takes a long time for the blur repair process.

  Therefore, an object of the present invention is to obtain an imaging apparatus, a control method thereof, and a control program that can obtain a still image in focus with a short release time lag with high accuracy when shooting from a live view state.

  In order to achieve the above object, an imaging apparatus according to the present invention is an imaging apparatus that repairs blurring of a captured image obtained as a result of imaging, and receives an optical image via a shooting lens and responds to the optical image. An image sensor that outputs an image signal; a first focus state detection unit that receives the optical image and outputs a first focus state detection result indicating whether or not the optical image is in focus; and A selection unit that selects one of a first state in which the optical image from the photographing lens is guided to the image sensor and a second state in which the optical image is guided to the first focus state detection unit; If it exists, after controlling the said selection means and starting exposure of the said image pick-up element as the said 1st state, the said selection means is controlled and based on the said 1st focus state detection result as the said 2nd state Deblurring of the shot image according to the image signal And having a cormorants control means.

  The control method according to the present invention includes an image sensor that receives an optical image through a photographing lens and outputs an image signal corresponding to the optical image, and receives the optical image through the photographing lens and focuses the optical image. A focus state detection means for outputting a focus state detection result indicating whether or not the image is in a state, and a method for controlling an imaging apparatus that repairs blurring of a captured image according to the image signal, When there is a selection step for selecting either the first state for guiding the optical image to the image sensor or the second state for guiding the optical image to the focus state detection means, and when there is a photographing instruction, After the exposure of the image sensor is started as the first state, blur correction of the captured image according to the image signal is performed as the second state by the selection step based on the focus state detection result as the second state. A method, characterized by having a.

  The control program according to the present invention includes an imaging device that receives an optical image via a photographic lens and outputs an image signal corresponding to the optical image, and receives the optical image via the photographic lens and focuses the optical image. A control program for use in an imaging apparatus that repairs blurring of a captured image according to the image signal, the imaging apparatus comprising: a focus state detection unit that outputs a focus state detection result indicating whether the image is in a state; A selection step of selecting either a first state in which the optical image from the photographic lens is guided to the image sensor or a second state in which the optical image is guided to the focus state detection unit. When the photographing instruction is given, after the exposure of the image sensor is started as the first state by the selection step, the focus state detection is performed as the second state by the selection step. Characterized in that to execute a control step of performing defocus correction of the captured image corresponding to the image signal based on the results.

  According to the present invention, it is possible to perform shooting while satisfying both the release time lag and the in-focus state.

1 is a block diagram illustrating a configuration of an example of an imaging apparatus according to a first embodiment of the present invention. It is a figure which shows schematically the circuit structure of the image pick-up element shown in FIG. It is a figure which shows the cross section of the pixel in the image pick-up element shown in FIG. 2A and 2B are diagrams for explaining a structure of an imaging pixel in the imaging element shown in FIG. 1, in which FIG. 1A is a plan view and FIG. 2B is a cross-sectional view taken along line AA shown in FIG. 2A and 2B are diagrams for explaining a structure of a focus detection pixel in the image sensor shown in FIG. 1, in which FIG. 1A is a plan view and FIG. 2B is a cross-sectional view taken along line BB shown in FIG. It is a figure which shows the focus detection position which can be set in phase difference AF. It is a figure which shows the focus detection position which can be set in contrast AF. 2 is a flowchart for explaining a photographing operation performed by the camera shown in FIG. 1. FIG. 9 is a flowchart for explaining a blur repair process shown in FIG. 8. FIG. 10 is a flowchart for explaining a blur function generation process shown in FIG. 9. It is a flowchart for demonstrating the imaging | photography operation | movement performed with the camera by the 2nd Embodiment of this invention. It is a flowchart for demonstrating the imaging | photography operation | movement performed with the camera by the 3rd Embodiment of this invention. It is a figure which shows the focus detection position by the imaging surface phase difference AF shown in FIG.

  Hereinafter, an example of an imaging apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing the configuration of an example of an imaging apparatus according to the first embodiment of the present invention.

  The illustrated imaging apparatus (hereinafter referred to as a camera) has a camera body 138 and a photographing lens unit (hereinafter simply referred to as a photographing lens) 137, and the photographing lens 137 can be exchanged for the camera body 138.

  The photographing lens 137 has a photographing optical system (imaging optical system), and this photographing optical system includes a first lens group 101. The first lens group 101 is held so as to be movable back and forth in the optical axis direction. A stop 102 is disposed at the subsequent stage of the first lens group 101, and the amount of light at the time of photographing is adjusted by adjusting the aperture diameter of the stop 102. A second lens group 103 is disposed at the subsequent stage of the diaphragm 102, and the diaphragm 102 and the second lens group 103 integrally move forward and backward in the optical axis direction, and change magnification in conjunction with the forward and backward movement of the first lens group 101. The action (zoom function) is performed. A third lens group 105 is disposed following the second lens group 103, and the third lens group 105 is advanced and retracted in the optical axis direction to perform focus adjustment.

  The zoom actuator 111 rotates a cam cylinder (not shown) to drive the first lens group 111 or the second lens group 103 forward and backward in the optical axis direction to perform a zooming action. The aperture actuator 112 controls the aperture diameter of the aperture 102 to adjust the amount of photographing light. The focus actuator 114 adjusts the focus by driving the third lens group 105 back and forth in the optical axis direction.

  The photographing lens 137 is provided with a camera communication circuit 136, and the camera communication circuit 136 communicates with a lens communication circuit 135 provided in the camera body 138. Then, the camera communication circuit 136 sends lens information regarding the photographing lens to the camera body 138. The camera communication circuit 136 receives camera information related to the camera body. Here, the lens information refers to, for example, a zoom state, an aperture state, a focus state, and lens frame information.

  The camera main body 138 is provided with an optical low-pass filter 106, and the optical low-pass filter 160 reduces false colors and moire of an optical image incident from the photographing lens 136. An image sensor 107 is arranged at the subsequent stage of the optical low-pass filter 106. The image sensor 107 is composed of, for example, a CMOS sensor and its peripheral circuits.

  The image sensor 107 has a plurality of pixels arranged in a two-dimensional matrix. Here, as the image sensor 107, a primary color in a Bayer array on light receiving pixels of m pixels (m is an integer of 2 or more) in the horizontal direction (row) and n pixels (n is an integer of 2 or more) in the vertical direction (column). A two-dimensional single plate color sensor in which a color mosaic filter is formed on-chip is used.

  A shutter unit 139 is disposed in front of the optical low-pass filter 106, and the shutter unit 139 adjusts the exposure time when taking a still image. The shutter unit 139 is driven by a shutter actuator 140.

  The subject certification electronic flash 115 is, for example, a flash illumination device using a xenon tube. In addition, you may make it use the illuminating device provided with LED which light-emits continuously as the electronic flash 115. FIG.

  The AF auxiliary light unit 116 projects an image of a mask having a predetermined aperture pattern onto the object field via a light projection lens, and improves focus detection for a dark subject or a low-contrast subject.

  The CPU 121 controls the camera body 138. Although not shown, the CPU 121 includes a calculation unit, a ROM, a RAM, an A / D converter, a D / A converter, a communication interface circuit, and the like, and controls the camera based on a predetermined program stored in the ROM. A series of processing such as shooting, image processing, blur correction (also referred to as blur restoration) of an image obtained as a result of shooting, and recording are executed. Further, the CPU 121 performs arithmetic processing related to phase difference AF (phase difference autofocus), arithmetic processing related to contrast AF, and phase difference AF (imaging surface phase difference autofocus) on the imaging surface.

  The electronic flash control circuit 122 controls lighting of the electronic flash 115 in synchronization with the photographing operation under the control of the CPU 121. The auxiliary light driving circuit 123 controls lighting of the AF auxiliary light unit 116 in synchronization with the focus detection operation under the control of the CPU 121. The image sensor driving circuit 124 controls the image capturing operation of the image sensor 107 under the control of the CPU 121, and A / D converts the output image signal to send it to the CPU 121 as image data. The image processing circuit 125 performs processing such as γ conversion, color interpolation, and JPEG compression on the image data under the control of the CPU 121.

  The focus drive circuit 126 controls the focus actuator 114 based on the focus detection result under the control of the CPU 121, and adjusts the focus by moving the third lens group 105 back and forth in the optical axis direction. The aperture driving circuit 128 controls the aperture of the aperture 102 by drivingly controlling the aperture actuator 112 under the control of the CPU 121. The zoom drive circuit 129 drives the zoom actuator 111 according to the photographer's zoom operation under the control of the CPU 121. The lens communication circuit 135 communicates with the camera communication circuit 136 of the photographing lens 137. The shutter drive circuit 145 drives the shutter actuator 140 under the control of the CPU 121.

  The display unit 131 is, for example, an LCD. The display unit 131 displays information related to the shooting mode of the camera, a preview image before shooting, a confirmation image after shooting, a focus state display image at the time of focus detection, and the like. Is done. The operation switch 132 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. The flash memory 133 is detachable from the camera body 138, and a captured image is recorded. The memory 144 stores various data necessary for calculations performed by the CPU 121.

  The main mirror 200 is constituted by a half mirror, and is obliquely provided in the photographing optical path in the observation state (preview state) (second state), and is retreated from the photographing optical path in the photographing state (first state). 1 state). A sub mirror 201 is disposed between the main mirror 200 and the shutter unit 139. The sub mirror 201 reflects the light beam transmitted through the main mirror 200 toward the lower side of the camera body. The imaging lens 137 is provided with a focus detection unit (phase difference AF unit) 202 for performing phase difference AF.

  The light from the subject passes through the taking lens 137 and then enters the main mirror 200. Part of the light incident on the main mirror 200 passes through the main mirror 200, is reflected by the sub mirror 201, and enters the AF unit 202. In the AF unit 202, a field detection lens and a secondary imaging lens constitute a focus detection optical system. The secondary imaging lens re-images the two incident light beams on the focus detection sensor. Thus, a subject image, which is a pair of optical images, is formed on the focus detection sensor by the light beams from the two pupil division regions. The focus detection sensor photoelectrically converts a pair of subject images and outputs a pair of image signals (electric signal: first focus state detection result).

  Here, the phase difference AF performed by the camera shown in FIG. 1 will be described.

  The CPU 121 performs a correlation operation on the pair of image signals and calculates a phase difference indicating a relative position shift of the image signals. Then, the CPU 121 calculates (detects) the focus state (defocus amount) of the photographing lens 1 based on the phase difference. Further, the CPU 121 calculates the amount of movement of the focus lens for achieving the in-focus state based on the defocus amount.

  The light reflected by the main mirror 200 forms an image on a focus plate (not shown) disposed at a position optically conjugate with the image sensor 107. The light is diffused on the focusing plate, and the light (subject image) transmitted through the focusing plate is converted into an erect image by a penta roof prism (not shown). The erect image is magnified by an eyepiece lens (not shown) and observed by a photographer.

  Here, the contrast AF performed by the camera shown in FIG. 1 will be described.

  Contrast AF is focus detection that detects the in-focus position by evaluating the contrast of the subject image captured by the image sensor 107 while driving the focus lens. Since the contrast AF is described in various documents, detailed description is omitted here.

  FIG. 2 is a diagram schematically showing a circuit configuration of the image sensor 107 shown in FIG.

  In FIG. 2, pixels of 2 columns × 4 rows are shown for the image sensor 107, but in reality, a large number of pixels are arranged in a two-dimensional matrix. Here, the image sensor 107 has, for example, a pixel pitch of 2 μm, an effective pixel count of 3000 horizontal rows × 2000 vertical rows = 6 million pixels, and an image capture screen size of 6 mm horizontal × 4 mm vertical.

  In FIG. 2, each of the pixels has a photoelectric conversion unit 1, which is a photoelectric conversion element including a MOS transistor gate and a depletion layer under the gate. Further, each pixel has a photogate 2 and a transfer switch MOS transistor 3.

  The illustrated image pickup element 107 includes a reset MOS transistor 4, a source follower amplifier MOS transistor 5, a horizontal selection switch MOS transistor 6, a source follower load MOS transistor 7, a dark output transfer MOS transistor 8, a bright output transfer MOS transistor 9, and a dark output. It has a storage capacitor (CTN) 10, a bright output storage capacitor (CTS) 11, a horizontal transfer MOS transistor 12, a horizontal output line reset MOS transistor 13, a differential output amplifier 14, a horizontal scanning circuit 15, and a vertical scanning circuit 16. Yes.

  The configuration of the image sensor is described in, for example, Japanese Patent Application Laid-Open No. 9-46596, so that further explanation is omitted here.

  FIG. 3 is a diagram illustrating a cross section of a pixel in the image sensor 107 illustrated in FIG. 1.

  In the P-type well 17, a gate oxide film 18, a first-layer poly Si 19, a second-layer poly Si 20, and an n + floating diffusion portion (FD) 21 are formed. It is. The FD 21 is connected to the photoelectric conversion unit via a transfer MOS transistor. In the example shown in the figure, the drains of the two transfer MOS transistors 3 and the FD 21 are made common and miniaturized and the sensitivity is improved by reducing the capacity of the FD 21. However, the FD 21 may be connected by an Al wiring.

  Next, imaging surface phase difference AF performed by the camera shown in FIG. 1 will be described.

  FIG. 4 is a diagram for explaining the structure of the imaging pixels in the imaging element 107 shown in FIG. 4A is a plan view, and FIG. 4B is a cross-sectional view taken along line AA shown in FIG. 4A. FIG. 5 is a diagram for explaining the structure of the focus detection pixels in the image sensor 107 shown in FIG. FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view taken along line BB shown in FIG. 5A.

  In the example shown in the figure, pixels having G (green) spectral sensitivity are arranged in two diagonal pixels out of four pixels in 2 rows × 2 columns, and R (red) and B (blue) are arranged in the other two pixels, respectively. A Bayer array in which pixels having a spectral sensitivity of 1) are arranged is used. A plurality of focus detection pixels having a structure to be described later are distributed and arranged in a predetermined rule between the Bayer arrays.

  In FIG. 4B, an on-chip microlens ML is disposed on the forefront of each pixel. After the microlens ML, an R (red) color filter CFR and a G (green) color filter CFG are arranged in the CFR. PD schematically shows the photoelectric conversion unit 1 described in FIG. 2, and CL is a wiring layer for forming signal lines for transmitting various signals in the image sensor. TL schematically shows the photographing optical system.

  Here, the microlens ML of the imaging pixel and the photoelectric conversion unit PD are configured to capture the light beam that has passed through the photographing optical system TL as effectively as possible. The exit pupil EP of the photographing optical system TL and the photoelectric conversion unit PD are in a conjugate relationship by the microlens ML, and the effective area of the photoelectric conversion unit PD is designed to be large.

  In FIG. 4B, the incident light beam of the R pixel has been described, but the G pixel and the B (blue) pixel have the same structure. Accordingly, the exit pupil EP corresponding to each of the RGB pixels for imaging has a large diameter, and the S / N of the image signal is improved by efficiently capturing the light flux from the subject.

  In FIG. 5A, SHA and SHB are a first pixel group and a second pixel group having different division forms. These first and second pixel groups SHA and SHB are distributed and arranged according to a predetermined rule between the Bayer arrays. Then, the CPU 121 calculates a focus shift amount in accordance with the phase difference between the subject images obtained from the first pixel group SHA and the second pixel group SHB.

  Specifically, when obtaining an image signal, the G pixel is a main component of luminance information. Since human image recognition characteristics are sensitive to luminance information, image quality degradation is likely to be noticed when G pixels are missing. On the other hand, the R or B pixel is a pixel that acquires color information. However, since humans are insensitive to color information, pixels that acquire color information are less likely to notice image quality deterioration even if there is some loss.

  Therefore, the G pixels out of the pixels in 2 rows × 2 columns are left as imaging pixels, and focus detection pixels are arranged at a predetermined ratio to some pixels at positions corresponding to R and B. This focus detection pixel is indicated by SHA and SHB in FIG.

The microlens ML and the photoelectric conversion unit PD have the same structure as the imaging pixel shown in FIG. Here, since the signal of the focus detection pixel is not used for image generation, a transparent film CF _W (colorless) is disposed instead of the color separation color filter. Further, since pupil division is performed by the image sensor 107, the opening of the wiring layer CL is decentered in the x direction with respect to the center line of the microlens ML.

Since the opening OP _HA of the pixel SHA is decentered in the −x direction, the light beam that has passed through the exit pupil EP _HA on the left side of the imaging optical system TL is received. Similarly, since the opening OP _HB of the pixel SHB is decentered in the + x direction, the light beam that has passed through the right exit pupil EP _HB of the photographing optical system TL is received. Here, the pixels SHA are regularly arranged in the x direction, and a subject image acquired by these pixel groups is defined as an A image. Similarly, the pixels SHB are also regularly arranged in the x direction, and a subject image acquired by these pixel groups is a B image. By detecting the relative positions of these A and B images, the amount of focus shift (defocus amount) of the subject image can be detected.

  In the pixels SHA and SHB, focus detection is possible for a subject having a luminance distribution in the x direction on the photographing screen, for example, a line in the y direction. If necessary, a pixel that performs pupil division is also provided in the y direction of the photographing lens so that focus detection can be performed on a subject having a luminance distribution in the y direction of the photographing screen, for example, a line in the x direction. May be.

  Note that a technique for discretely disposing focus detection pixels between imaging pixels and a technique for performing focus detection using the focus detection pixels are described in Patent Document 1, and here, more details are described here. The detailed explanation is omitted.

  The imaging surface phase difference AF can detect a focus in a wider range than the phase difference AF. However, since the imaging surface phase difference AF is greatly affected by lens vignetting, the accuracy of focus detection is inferior to the phase difference AF.

  FIG. 6 is a diagram showing focus detection positions that can be set in the phase difference AF.

  In the phase difference AF, for example, focus detection positions 600 to 604 are discretely provided in an imaging region 605 indicated by an outer frame, and an arbitrary position is selected from these focus detection positions 600 to 604 at the time of focus detection. It is possible to set.

  FIG. 7 is a diagram showing focus detection positions that can be set in contrast AF.

  In contrast AF, nine 3 × 3 areas 610 to 618 are provided in an imaging area 619 indicated by an outer frame, and an arbitrary area is selected and set from these areas 610 to 618 when focus detection is performed. Is possible.

  As shown in FIG. 6 and FIG. 7, in the phase difference AF and the contrast AF, line sensors for detecting the phase difference are discretely arranged, so that the focus detection positions (areas) that can be set are different.

  FIG. 8 is a flowchart for explaining a photographing operation performed by the camera shown in FIG. Note that the processing in the flowchart shown in FIG. 8 is performed by the CPU 121 shown in FIG.

  Now, when the photographer turns on the power switch of the camera (step S101), the CPU 121 confirms the operation of the actuator and the image sensor in the camera. Further, the CPU 121 initializes the memory contents and the execution program, reads out information necessary for distance measurement, such as the selected focus detection position, from the memory, and performs a shooting preparation operation (step S102).

  Subsequently, the CPU 121 performs lens communication with the camera communication circuit 136 of the photographing lens 137 via the lens communication circuit 135 (step S103). By this lens communication, the CPU 121 confirms the operation of the photographing lens 137, initializes the memory contents of the photographing lens 137 and the execution program, and executes a preparatory operation. Further, the CPU 121 acquires characteristic data indicating the characteristics of the photographing lens necessary for focus detection and imaging from the imaging lens 137 and stores it in the memory 144 as lens characteristic data.

  In the memory 144, characteristic data indicating the specification of the camera body 138 is recorded as camera characteristic data.

  Next, the CPU 121 determines whether or not live view shooting has been instructed by the photographer (step S104). If live view shooting is not instructed (NO in step S104), CPU 121 enters a shooting standby state. On the other hand, when live view shooting is instructed (YES in step S104), CPU 121 places main mirror 200 in a mirror-up state. Here, after retracting the main mirror 200 and the sub mirror 201, the CPU 121 opens the shutter unit 139 and sets the image sensor 107 to a light receiving state (step S105).

  Subsequently, the CPU 121 drives the image sensor 107 by the image sensor drive circuit 123 (step S106). Then, the CPU 121 displays a preview image on the display unit 131 (step S107). As a result, the photographer visually determines the composition at the time of photographing by viewing the preview image.

  During the live view shooting operation, the CPU 121 performs continuous AF by contrast AF so that the focus detection position read in step S102 is always in focus.

  Subsequently, the CPU 121 determines whether or not the photographer has instructed to shoot a still image (step S108). If there is no still image shooting instruction (NO in step S108), the CPU 121 maintains the live view shooting state while performing continuous AF.

  When still image shooting is instructed (YES in step S108), the CPU 121 starts the imaging operation of the image sensor 107 and performs exposure (step S109). Then, the CPU 121 determines whether or not the focus detection position read in step S102 is a focus detection position where focus detection is possible by phase difference AF (step S110). In other words, the CPU 121 determines whether or not the photographing condition allows detection by the phase difference AF.

  Here, the focus detection positions (areas) 611, 613, 614, 615, and 617 in the contrast AF shown in FIG. 7 are the focus detection positions 600, 601, 602, 603, and 604 in the phase difference AF shown in FIG. Corresponding, focus detection is possible by phase difference AF.

  On the other hand, the focus detection positions 610, 612, 616, and 618 in the contrast AF cannot be detected by the phase difference AF because there is no focus detection position corresponding to the phase difference AF. That is, in step S110, the CPU 121 determines whether or not the focus detection position in contrast AF is a position where focus detection is possible with phase difference AF.

  If the focus detection position in contrast AF is a position where focus detection is possible with phase difference AF (YES in step S110), CPU 121 enters a mirror-down state. That is, the CPU 121 lowers the retracted main mirror 200 and sub mirror 201 so that the AF unit (focus detection sensor) 202 can receive light (step S111).

  Next, the CPU 121 detects the amount of focus deviation based on the phase difference of the subject due to the phase difference AF (step S112). At this time, the CPU 121 sets the focus detection position to be the same as or close to the focus detection position in contrast AF. For example, if the focus detection position 611 in contrast AF is set, the CPU 121 performs focus detection at the focus detection position 601 in phase difference AF.

  Subsequently, the CPU 121 performs a blur repair process based on the focus shift amount obtained in step S112 (step S113). This blur repair process will be described later. Then, after the blur repair process, the CPU 121 ends the photographing operation.

  If the focus detection position in contrast AF is not a position where focus detection is possible with phase difference AF (NO in step S110), CPU 121 indicates on display 131 that the focus detection position is outside the range where focus detection is possible using phase difference AF. This is displayed to warn the photographer that phase difference AF for blur restoration cannot be performed (step S114). Then, the CPU 121 ends the shooting operation.

  Here, the warning is displayed on the display unit 131. However, any notification may be performed as long as the photographer can be informed that desired shooting cannot be performed, for example, by generating sound.

  As described above, in the blur restoration process, the CPU 121 restores the image based on the focus amount obtained at the set distance measuring point (focus detection position). The blur generation process can be estimated from the characteristics of the camera and the characteristics of the photographing lens. Here, a blur function that models the blur generation process is defined, and the blur image is restored using an image restoration algorithm called deconvolution such as a Wiener filter. The calculation method used when restoring the blurred image is described in, for example, Japanese Patent Application Laid-Open No. 2004-151620, and thus detailed description thereof is omitted here.

  FIG. 9 is a flowchart for explaining the blur repair process shown in FIG.

  When the blur repair process is started, the CPU 121 acquires conversion information indicating the content of the conversion process (that is, image process) performed by the image processing circuit 125 (step S501). Then, the CPU 121 determines a conversion method for converting the image data sent from the image processing circuit 125 (step S502).

  Here, the CPU 121 determines a conversion method based on the lens information acquired in step S103 of FIG. In the conversion method determined in step S502, for example, in order to ensure linearity, which is a precondition of the image restoration processing algorithm described in Patent Document 1, the exposure value and the pixel value are in a proportional relationship. Convert image data.

  For example, when gamma correction is executed by the image processing circuit 125, inverse conversion of conversion by gamma correction is performed by the method determined in step S502. As a result, the image data before gamma correction can be reproduced, and image data having linearity can be acquired.

  Similarly, when color correction is executed by the image processing circuit 125, the inverse conversion of the conversion by the color conversion is performed by the method determined in step S502. This makes it possible to acquire image data having linearity in the same manner.

  Thus, in step 502, a conversion method corresponding to the inverse conversion of the conversion processing by the image processing circuit 125 is determined.

  Subsequently, the CPU 121 acquires image data (captured image) from the image processing circuit 125 (step S503). Then, the CPU 121 converts image data according to the conversion method determined in step S502 (step S504). Thereafter, the CPU 121 generates a blur function (step S600).

  Next, the CPU 121 performs inverse transformation of the blur function, and performs blur restoration processing on the image data converted in step S504 (step S505). Then, the CPU 121 ends the blur repair process.

  In the blur restoration process, the blur restoration process is performed by an image restoration algorithm called a deconvolution process. As a result, it is possible to obtain blur-repaired image data in which the blur of a predetermined subject is repaired. For example, Patent Document 1 discloses a technique for performing blur restoration by inversely transforming a blur function, and thus a detailed description thereof is omitted here.

  FIG. 10 is a flowchart for explaining the blur function generation processing shown in FIG.

  When the blur function generation process is started, the CPU 121 acquires camera characteristic data recorded in the memory 144 (step S601). Subsequently, the CPU 121 acquires lens characteristic data recorded in the memory 144 (step S602). Next, the CPU 121 obtains parameters used when defining the blur function from the memory 144 (step S603).

  Incidentally, the blur function is determined by the light transfer characteristic between the photographing lens 137 and the image sensor 107. The light transfer characteristic changes depending on factors such as camera characteristic data, lens characteristic data, the position of the subject area in the captured image, and the subject distance. Also, the blur function changes greatly depending on the amount of focus shift.

  For this reason, table data in which the above-described factors are associated with parameters (blur parameters) used when defining the blur function is stored in the memory 144 in advance. Further, the focus shift amount obtained in step S112 of FIG. 8 is used as the focus shift amount used when defining the blur function.

  Next, the CPU 121 defines a blur function based on the blur parameter (step S604). Here, as the blur function, there is a Gaussian distribution in which the blur phenomenon conforms to the normal distribution law. If the distance from the center pixel is r and the arbitrary parameter of the normal distribution law is σ2, the blur function h (r) is expressed by the following equation (1).

  When the blur function is defined, the CPU 121 ends the blur function generation process.

  Thus, in the first embodiment of the present invention, when shooting a still image from live view shooting (preview state), the image sensor is exposed without waiting for the completion of the focusing operation. A still image at the moment intended by the photographer can be obtained.

  In addition, since the blurred image is restored based on the defocus amount detected by the phase difference AF, it is possible to easily obtain an optimum filter for performing the blur restoration, and it is possible to more accurately with a short processing time. Defocusing can be repaired.

[Second Embodiment]
Next, a camera according to a second embodiment of the present invention will be described. The configuration of the camera according to the second embodiment is the same as that of the camera shown in FIG.

  FIG. 11 is a flowchart for explaining a photographing operation performed by the camera according to the second embodiment of the present invention. Note that the processing in the flowchart shown in FIG. 11 is performed by the CPU 121 shown in FIG. In FIG. 11, the same steps as those shown in FIG. 8 are denoted by the same reference numerals, and the description thereof is omitted.

  In step S110 described with reference to FIG. 8, if the focus detection position in contrast AF is not a position where focus detection is possible with phase difference AF (NO in step S110), CPU 121 uses contrast AF at a preset focus detection position in contrast AF. Then, focus detection is performed, and focus adjustment is performed according to the focus detection result (second focus state detection result) (step S714). When the focus adjustment is completed, the CPU 121 starts the imaging operation of the image sensor 107 and performs exposure (step S715).

  Subsequently, the CPU 121 selects either or both of the image (first image) obtained in step S109 and the image (second image) obtained in step S715 by the photographer or neither of them. It is determined whether or not there is an instruction (step S716). Here, the photographer can select either the shutter priority image obtained in step S109 or the focus priority image obtained in step S716. Of course, the photographer can select both images and not select both images.

  If there is no instruction (NO in step S716), CPU 121 stands by. On the other hand, if there is an instruction (YES in step S716), CPU 121 performs processing according to the instruction and ends the photographing operation.

  As described above, also in the second embodiment of the present invention, when shooting a still image from live view shooting, the image sensor is exposed without waiting for the completion of the focusing operation. A picture can be obtained.

  Further, in the second embodiment, when the focus detection by the phase difference AF can be performed at the focus detection position set for the contrast AF, the blurred image is repaired based on the defocus amount detected by the phase difference AF. Therefore, it is possible to easily obtain an optimum filter for performing blur repair, and to perform blur repair with high accuracy in a short processing time. When focus detection by phase difference AF cannot be performed at the focus detection position set for contrast AF, the still image at the moment intended by the photographer and the still image that is accurately focused by contrast AF Get both of the drawings. Thus, the photographer can select a still image giving priority to the release time lag or a still image giving priority to the focus state according to the situation.

[Third Embodiment]
Subsequently, a camera according to a third embodiment of the present invention will be described. The configuration of the camera according to the third embodiment is the same as that of the camera shown in FIG.

  FIG. 12 is a flowchart for explaining a photographing operation performed by the camera according to the third embodiment of the present invention. The processing in the flowchart shown in FIG. 12 is performed by the CPU 121 shown in FIG. In FIG. 12, the same steps as those shown in FIG. 8 are denoted by the same reference numerals, and the description thereof is omitted.

  In step S110 described in FIG. 8, if the focus detection position in contrast AF is not a position where focus detection is possible by phase difference AF (NO in step S110), CPU 121 is the same as the focus detection position set in advance by contrast AF. Alternatively, focus detection by the imaging surface phase difference AF is performed in the vicinity thereof (step S814). Then, the CPU 121 performs focus adjustment by driving the focus lens based on the focus detection result (third focus state detection result).

  FIG. 13 is a diagram showing a focus detection position in the imaging plane phase difference AF shown in FIG.

  As shown in FIG. 13, the focus detection position in the imaging surface phase difference AF is one region 1301 that is the entire imaging surface, and this region 1301 is the focus detection position 610, 611, 612 of contrast AF shown in FIG. , 613, 614, 615, 617, and 618. Therefore, in the imaging plane phase difference AF, focus detection can be performed in the same range as that in which the focus can be detected by contrast AF.

  Subsequently, the CPU 121 performs a blur repair process based on the focus shift amount obtained by the imaging plane phase difference AF (step S815), and ends the photographing. Note that the blur repair process in step S815 is performed in the same manner as the blur repair process in step S113 described with reference to FIG.

  As described above, also in the third embodiment of the present invention, when shooting a still image from live view shooting, the image sensor is exposed without waiting for the completion of the focusing operation. A picture can be obtained.

  Further, in the third embodiment, when the focus detection by the phase difference AF can be performed at the focus detection position set for the contrast AF, the blurred image is repaired based on the defocus amount detected by the phase difference AF. Therefore, it is possible to easily obtain an optimum filter for performing blur repair, and to perform blur repair with high accuracy in a short processing time. Even when focus detection by phase difference AF cannot be performed at the focus detection position set for contrast AF, the blurred image is restored based on the defocus amount obtained by imaging plane phase difference AF. As a result, it is possible to easily obtain an optimum filter at the time of blur repair, and to perform blur repair with high accuracy in a short processing time.

  In the above-described embodiment, the camera in which the photographing lens can be replaced is described as the imaging device. However, the present invention can also be applied to a so-called lens attachment type camera in which the photographing lens is provided in the camera body.

  As is clear from the above description, in the example shown in FIG. 1, the phase difference AF unit 202 functions as a first focus state detection unit. The main mirror 200 and the sub mirror 201 function as selection means, and the CPU 121 and the image processing circuit 125 function as control means.

  Further, the focus actuator 114, the focus drive circuit 126, and the CPU 121 function as a second focus state detection unit, and the CPU 121 functions as a determination unit. The CPU 121 functions as third focus state detection means. The CPU 121 and the operation switch 132 function as image selection means.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to these embodiment, Various forms of the range which does not deviate from the summary of this invention are also contained in this invention. .

  For example, the function of the above embodiment may be used as a control method, and this control method may be executed by the image processing apparatus. In addition, a program having the functions of the above-described embodiments may be used as a control program, and the control program may be executed by a computer included in the image processing apparatus. The control program is recorded on a computer-readable recording medium, for example.

  Each of the above control method and control program has at least a selection step and a control step.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various recording media, and the computer (or CPU, MPU, etc.) of the system or apparatus reads the program. To be executed.

107 Image sensor 121 CPU
124 Image sensor driving circuit 131 Display unit 137 Shooting lens unit 138 Camera body 200 Main mirror 201 Sub mirror 202 Phase difference AF unit

Claims (8)

An imaging apparatus for repairing blurring of a captured image obtained as a result of imaging,
An image sensor that receives an optical image via a photographic lens and outputs an image signal corresponding to the optical image;
First focus state detection means for receiving the optical image and outputting a first focus state detection result indicating whether or not the optical image is in focus;
Selecting means for selecting one of a first state for guiding the optical image from the photographing lens to the image sensor and a second state for guiding the optical image to the first focus state detecting means;
When there is a photographing instruction, the selection unit is controlled to start exposure of the image sensor as the first state, and then the selection unit is controlled to set the second state to the first focus state detection result. Control means for performing blur repair of a captured image according to the image signal based on
An imaging device comprising: The first focus state detection means outputs the first focus state detection result by phase difference autofocus,
The photographing lens is equipped with a focus lens,
Second focus state detection indicating whether or not a focus state is obtained by evaluating the contrast of a captured image corresponding to the image signal obtained by the image sensor while driving the focus lens along an optical axis. Second focus state detection means for outputting a result;
2. The apparatus according to claim 1, further comprising: a determination unit that determines whether or not the imaging condition is capable of being detected by the first focus state detection unit according to the second focus state detection result. Imaging device.   3. The control unit issues a warning without setting the second state when it is determined by the determining unit that the photographing condition is not capable of being detected by the first focus state detecting unit. The imaging device described in 1.   If it is determined by the determining means that the photographing condition is not capable of being detected by the first focus state detecting means, the control means displays the first image in the first state without setting the second state. The imaging apparatus according to claim 2, wherein the second image is obtained by performing focus adjustment according to the second focus state detection result.   The imaging apparatus according to claim 4, further comprising an image selection unit that selects at least one of the first image and the second image as a captured image. The image pickup device includes a first pixel group and a second pixel group having different division forms,
Third focus state detection result by performing imaging surface phase difference autofocus for detecting whether or not the focus state is in accordance with the phase difference of the image signals from the first pixel group and the second pixel group. And a third focus state detection means for outputting
If it is determined by the determination unit that the shooting condition is not detectable by the first focus state detection unit, the control unit is based on the third focus state detection result without setting the second state. The imaging apparatus according to claim 2, wherein blur correction of a captured image corresponding to the image signal is performed. An image sensor that receives an optical image through a photographic lens and outputs an image signal corresponding to the optical image, and whether the optical image is in focus by receiving the optical image through the photographic lens. A focus state detection unit that outputs a focus state detection result to indicate, and a method of controlling an imaging apparatus that repairs blur of a captured image according to the image signal,
A selection step of selecting one of a first state in which the optical image from the photographing lens is guided to the image sensor and a second state in which the optical image is guided to the focus state detection unit;
When there is a shooting instruction, after the selection step starts exposure of the image sensor as the first state, the selection step determines the second state according to the image signal based on the focus state detection result. A control step for blurring the shot image;
A control method characterized by comprising: An image sensor that receives an optical image through a photographic lens and outputs an image signal corresponding to the optical image, and whether the optical image is in focus by receiving the optical image through the photographic lens. A control program for use in an imaging device that includes a focus state detection unit that outputs a focus state detection result that indicates a blur of a captured image corresponding to the image signal,
In the computer provided in the imaging device,
A selection step of selecting one of a first state in which the optical image from the photographing lens is guided to the image sensor and a second state in which the optical image is guided to the focus state detection unit;
When there is a shooting instruction, after the selection step starts exposure of the image sensor as the first state, the selection step determines the second state according to the image signal based on the focus state detection result. A control step for blurring the shot image;
A control program characterized by causing

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