JP6628678B2 - Distance measuring device, imaging device, and distance measuring method - Google Patents

Description

  The present invention relates to a distance measurement technique, and particularly to a distance measurement technique used for a digital still camera, a digital video, and the like.

  As a distance detection technique applicable to a digital still camera or a video camera, a distance detection technique using a phase difference method is known. In this method, light images (hereinafter, referred to as “A image” and “B image”, respectively) formed by light beams passing through different pupil regions are acquired. Calculate the image shift amount (also referred to as parallax), which is the relative position shift amount between the A image and the B image, based on the base line length, which is the distance between the centers of gravity forming the A image and the B image on the lens pupil. The distance to the subject can be calculated by converting to a defocus amount via the converted conversion coefficient.

  At this time, it is known that the conversion coefficient changes due to various factors at the peripheral angle of view. Factors of the change include, for example, a change in pupil shape due to vignetting (also referred to as “vignetting”) caused by vignetting of a lens frame or the like of an imaging optical system, chromatic aberration characteristics, and spectral sensitivity to an incident angle of a ranging pixel. Characteristics, camera manufacturing errors, and the like. In addition, the conversion coefficient changes in accordance with the defocus amount itself. Patent Literature 1 describes a method of correcting a change in a conversion coefficient.

  In recent years, digital still cameras and video cameras have been equipped with various image stabilizing functions to prevent image blurring caused by camera shake or the like. For example, Patent Literature 2 discloses a technique for suppressing image blur by shifting a part of a lens system. Specifically, since the state of the amount of light and the state of distortion change due to the shift of the lens system, in Patent Document 2, distortion correction is performed according to the position information of the image blur correction optical system.

JP-A-2015-212772 JP 2012-231262 A JP 2013-222183 A

  It is preferable that the imaging device (digital still camera or video camera) provided with the distance measuring device is portable. By carrying the camera and photographing from an appropriate position, a distance map having an intended composition can be obtained. In addition, a high-density and high-accuracy distance map can be obtained by taking a picture from a nearby place due to the geometric principle and the characteristics of the digital system.

  A portable camera is vulnerable to camera shake, and therefore it is desirable to mount a vibration isolation mechanism. However, when image correction is performed in accordance with the amount of light and image distortion that fluctuate by the method described in Patent Literature 2, fluctuations in image brightness, distortion, and the like can be suppressed, while distance measurement can be performed. The related conversion factor fluctuates. That is, there is a problem that an error occurs in the distance measurement.

  The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a technique capable of performing accurate distance measurement even when an image stabilizing mechanism is effective in an imaging apparatus.

The first aspect of the present invention,
Image blur correction means,
Based on a first image based on a light beam that has passed through a first pupil region of the imaging optical system and a second image based on a light beam that has passed through a second pupil region of the imaging optical system, a distance Distance information acquisition means for acquiring information;
A distance information correcting unit that corrects the distance information based on an image blur correction amount by the image blur correcting unit;
Equipped with a,
The distance information obtaining unit is configured to obtain an image shift amount between the first image and the second image, and the image shift amount from the image shift amount using a conversion coefficient corresponding to a pixel position. Second acquisition means for acquiring distance information,
The distance information correcting unit includes a third obtaining unit that obtains the conversion coefficient based on the image blur correction amount,
The third obtaining unit changes a method of obtaining the conversion coefficient according to the magnitude of the image blur correction amount,
It is a distance measuring device.
A second aspect of the present invention provides
Image blur correction means,
Based on a first image based on a light beam that has passed through a first pupil region of the imaging optical system and a second image based on a light beam that has passed through a second pupil region of the imaging optical system, a distance Distance information acquisition means for acquiring information;
A distance information correcting unit that corrects the distance information based on an image blur correction amount by the image blur correcting unit;
Image correction means for determining an image correction filter based on the amount of image blur correction by the image blur correction means, and performing image correction processing of the first image and the second image using the image correction filter,
With
The distance information obtaining unit is configured to obtain an image shift amount between the first image and the second image, and the image shift amount from the image shift amount using a conversion coefficient corresponding to a pixel position. Second acquisition means for acquiring distance information,
The second obtaining means obtains the distance information from the first image and the second image after the image correction processing by the image correcting means,
It is a distance measuring device.

A third aspect of the present invention provides:
Based on a first image based on a light beam that has passed through a first pupil region of the imaging optical system and a second image based on a light beam that has passed through a second pupil region of the imaging optical system, a distance A distance information obtaining step of obtaining information;
An obtaining step of obtaining an image blur correction amount by the image blur correcting means,
A distance information correction step of correcting the distance information based on the image blur correction amount,
Only including,
The distance information obtaining step is a first obtaining step of obtaining an image shift amount between the first image and the second image, and the image shift amount is calculated from the image shift amount using a conversion coefficient corresponding to a pixel position. A second acquisition step of acquiring distance information,
The distance information correcting step includes a third obtaining step of obtaining the conversion coefficient based on the image blur correction amount,
In the third obtaining step, a method of obtaining the conversion coefficient is changed according to the magnitude of the image blur correction amount,
This is a distance measuring method.
A fourth aspect of the present invention provides:
Based on a first image based on a light beam that has passed through a first pupil region of the imaging optical system and a second image based on a light beam that has passed through a second pupil region of the imaging optical system, a distance A distance information obtaining step of obtaining information;
An obtaining step of obtaining an image blur correction amount by the image blur correcting means,
A distance information correction step of correcting the distance information based on the image blur correction amount,
Determine an image correction filter based on the image blur correction amount, an image correction step of performing image correction processing of the first image and the second image using the image correction filter,
Including
The distance information obtaining step is a step of obtaining an image shift amount between the first image and the second image.
One acquisition step, including a second acquisition step of acquiring the distance information from the image shift amount using a conversion coefficient according to the position of the pixel,
In the second obtaining step, the distance information is obtained from the first image and the second image after the image correction processing by the image correction step,
This is a distance measuring method.

  According to the present invention, distance measurement can be performed with high accuracy even in an image pickup apparatus in which a vibration isolation mechanism is enabled.

1 is a schematic configuration diagram of a distance measuring device according to a first embodiment. FIG. 4 is a diagram illustrating basic processing according to the first embodiment. FIG. 3 is a diagram illustrating an image stabilizing function of the distance measuring device according to the first embodiment. FIG. 7 is a diagram illustrating geometric deformation of a conversion coefficient map according to the first embodiment. FIG. 5 is a diagram illustrating a distance measurement process of an arithmetic processing unit according to the first embodiment. FIG. 14 is a diagram illustrating a conversion coefficient map of a vector element according to the second embodiment. FIG. 13 is a diagram illustrating a distance measurement process of an arithmetic processing unit according to the second embodiment. FIG. 2 is a top view of a main part of an image sensor 103. FIG. 14 is a diagram illustrating a change in a pupil transmittance distribution due to vignetting in Embodiment 3. FIG. 14 is a diagram illustrating a distance measurement process of an arithmetic processing unit according to a third embodiment. FIG. 14 is a diagram illustrating a conversion coefficient and an image correction coefficient map according to the third embodiment. FIG. 14 is a diagram illustrating an image correction filter coefficient according to the third embodiment.

(Embodiment 1)
The present embodiment is an imaging device including a distance measuring device for obtaining distance information. The distance information is a value corresponding to the distance between a certain reference point and the subject. Typically, the distance (absolute distance) between the distance measuring device and the subject corresponds to the distance information. Generally, the distance information may be another value obtained from the distance between the imaging device and the subject. Another example of the distance information is a distance between the focus position of one image and the subject and a distance between an intermediate position between the focus positions of the two images and the subject. Further, the distance information may be either the distance on the image plane side or the distance on the object side. Further, the distance information may be represented by a distance in a real space, or may be represented by an amount that can be converted into a real space distance such as a defocus amount or a parallax amount. Thus, the distance information is a value that changes depending on the distance (absolute distance) between the imaging device and the subject. Therefore, the distance information may be referred to as a distance-dependent value.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings.

<Configuration of distance measuring device>
FIG. 1A is a schematic diagram illustrating an imaging device 100 including a distance measuring device according to the present invention. The imaging device 100 includes an imaging optical system 101, a distance measurement device 102, an attitude sensor 140, and an image blur correction unit 150. The distance measuring device 102 includes an arithmetic processing unit 104 and a memory 105. The imaging optical system 101 includes an image blur correction member 1011 (not shown in FIG. 1A).

The arithmetic processing unit 104 is configured by a logic circuit such as an ASIC (Application Specific Integrated Circuit). In another embodiment, the arithmetic processing unit 104 includes a general-purpose processor such as a CPU (Central Processing Unit) and a memory for storing a program, and executes the following processing by executing the program by the general-purpose processor. The arithmetic processing unit 104 functions as a distance information acquisition unit and a distance information correction unit as a whole. More specifically, as shown in FIG. 5A, the arithmetic processing unit 104 includes an image acquisition unit 11, an image shift amount calculation unit (first acquisition unit) 12, an image blur correction amount acquisition unit 13, It has a coefficient calculation unit (third acquisition unit) 14 and a distance calculation unit (second acquisition unit) 15 as its functional units. Specific description of each of these functional units will be described later.

  FIG. 1B is a diagram illustrating a configuration of the image sensor 103. The image sensor 103 is configured by arranging a large number of ranging pixels (hereinafter, also simply referred to as “pixels”) 110R, 110G, and 110B arranged on an xy plane.

  FIG. 1C is a cross-sectional configuration diagram of the ranging pixels 110R, 110G, and 110B. The ranging pixel includes a microlens 111, color filters 122R, 122G, 122B, photoelectric conversion units 110Ra, 110Rb, 110Ga, 110Gb, 110Ba, 110Bb, and a waveguide 113. Hereinafter, the photoelectric conversion units 110Ra, 110Ga, and 110Ba may be collectively referred to as a photoelectric conversion unit 110a, and the photoelectric conversion units 110Rb, 110Gb, and 110Bb may be collectively referred to as a photoelectric conversion unit 110b.

  Each pixel of the image sensor 103 is given spectral characteristics according to the wavelength band to be detected by the color filters 122R, 122G, and 122B, and mainly acquires red light, green light, and blue light, respectively. The distance measurement pixels 110R, 110G, and 110B are arranged on the xy plane by a known color arrangement pattern (for example, Bayer arrangement) not shown. The substrate 124 is made of a material that absorbs a wavelength band to be detected, for example, Si. On the substrate 124, a photoelectric conversion portion is formed in at least a part of the internal region by ion implantation or the like. Each pixel includes a wiring (not shown).

  Light beams that have passed through the first pupil region 131a and the second pupil region 131b, which are different regions in the exit pupil 130, respectively enter the photoelectric conversion unit 110a and the photoelectric conversion unit 110b, and the first signal and the second signal respectively. 2 is output. The photoelectric conversion unit that obtains the first signal forming the A image is called an A pixel, and the photoelectric conversion unit that obtains the second signal forming the B image is called a B pixel. The signal acquired by each photoelectric conversion unit is transmitted to the arithmetic processing unit 104, and the distance measurement arithmetic processing is performed.

<Basic flow of distance calculation>
FIG. 2 shows an example of a basic flowchart of the distance measurement calculation process.

[Image shift amount calculation]
In the image shift amount calculation processing in step S201, the image acquisition unit 11 reads out the image A (image of the first signal) and the image B (image of the second signal) from the memory, and the image shift amount calculation unit 12 outputs the image A Image shift amount, which is a relative position shift amount between the image B and the B image. A known method can be used to calculate the image shift amount. The correlation value S (k) is calculated, for example, from the image signal data A (i) and B (i) of the A image and the B image using Expression (1).

  In equation (1), S (j) is a correlation value indicating a degree of correlation between two images in the image shift amount j, i is a pixel number, and j is a relative image shift amount between the two images. p and q indicate target pixel ranges used for calculating the correlation value S (j). The lower the correlation value S (j), the higher the correlation.

  The image shift amount calculation unit 12 obtains the correlation value S (j) for j in the predetermined range, and determines the image shift amount j that gives the minimum value as the image shift amount between the A image and the B image at the position i. Note that the method of calculating the image shift amount is not limited to the method of the present embodiment, and another known method may be used.

[Defocus amount calculation]
In the distance calculation processing in step S202, the distance calculation unit 15 calculates the defocus amount from the image shift amount. An image of the subject 106 is formed on the image sensor 103 via the image forming optical system 101. FIG. 1A shows a state in which a light beam that has passed through the exit pupil 130 is focused on an imaging surface 107 different from the imaging surface, that is, a defocused state. Note that defocusing refers to a state where the imaging surface 107 does not coincide with the imaging surface (light receiving surface) and is shifted in the direction of the optical axis 108. The defocus amount indicates a distance between the imaging surface of the imaging element 103 and the imaging surface 107. The distance measuring device according to the present embodiment detects the distance of the subject 106 based on the defocus amount.

The image shift amount r indicating the relative position shift between the A image and the B image based on the first signal and the second signal acquired by each of the photoelectric conversion units 110a and 110b of the pixel 110, and the defocus amount ΔL , Equation (2).

  In Expression (2), W is the base line length, and L is the distance from the imaging element (imaging plane) 103 to the exit pupil 130. The base line length W corresponds to a center-of-gravity interval of a pupil sensitivity distribution obtained by projecting a sensitivity distribution with respect to an incident angle of a pixel described later on the exit pupil 130 surface.

Equation (2) can be written as equation (3) using the conversion coefficient K.

  The coefficient for converting the image shift amount into the defocus amount is hereinafter referred to as “conversion coefficient”. The conversion coefficient refers to, for example, the base line length W. Hereinafter, the correction of the base line length W is equivalent to the correction of the conversion coefficient. In the present embodiment, the conversion coefficient calculated by the conversion coefficient calculation unit 14 is used for distance calculation. The method of determining (correcting) the conversion coefficient will be described later.

  The method of calculating the defocus amount is not limited to the above method, and another known method may be used.

  When the photographing lens is a zoom lens, when the position of the exit pupil and the position of the sensor pupil change due to a change in the zoom state, the shape of the transmittance distribution (light-receiving amount distribution) on the exit pupil changes. This change depends on the image height. Therefore, the value of the base length W, which is the center of gravity of the transmittance distribution on the pupil, and the conversion coefficient K related to the base length W also have different values according to the image height. The base line length W or the conversion coefficient K corresponding to the change in the transmittance distribution is stored in the memory 105 as a two-dimensional table corresponding to the pixel position as shown in FIG.

<Structure of anti-vibration mechanism>
The suppression of image blur by the image blur correction member 1011 will be described. In the present embodiment, the image blur correction unit 150 moves a part of the lens (correction member 1011) of the imaging optical system 101 in parallel as shown in FIG. Thereby, the position of the optical image on the image sensor moves in parallel, and the image shake due to camera shake, so-called shake, can be suppressed.

  Instead of providing the correction member 1011 in the imaging optical system 101, a mechanical drive component (corresponding to a correction member) such as a piezo element that translates the image sensor 103 in a plane perpendicular to the optical axis of the imaging optical system 101. May be provided to suppress image blur. Further, for example, a vibration damping mechanism for controlling a range of an image output as an image signal from the image sensor 103 and electronically damping vibration due to camera shake may be provided.

  The camera shake is detected by the posture sensor 140. The attitude sensor 140 is formed of, for example, a gyro, and is attached to an arbitrary axis orthogonal to the optical axis of the optical system. The posture sensor 140 measures information on the posture change, and transmits the measured information to the image blur correction unit 150. For example, when the attitude sensor 140 is a rotation sensor, the attitude sensor 140 is attached to each axis of the imaging device in the yaw direction and the pitch direction, and measures a change in attitude due to rotation about each axis. The posture sensor 140 may be a sensor that measures the parallel movement of the imaging device, such as an acceleration sensor, or a sensor that calculates the amount of image blur caused by the parallel movement of the imaging device. In addition, the attitude sensor 140 may be a sensor that calculates the amount of image blur due to relative rotation / translation of the imaging device from the image vector.

  The image blur correction unit 150 controls the position and orientation of the correction member 1011 so as to cancel the image blur. The movement amount of the correction member 1011 is calculated based on the posture and / or position change of the imaging device measured by the posture sensor 140, or image blur caused by the posture and / or position change. The movement of the correction member 1011 is performed by driving a unit including the correction member 1011 with an electromagnetic coil or the like. Further, the image blur correction unit 150 has a function of detecting position and orientation information of the correction member 1011. The image blur correction unit 150 includes a Hall element or an encoder in the configuration, and measures the position and orientation information of the correction member 1011 based on the position on the trajectory of the lens assembly unit that performs optical image stabilization. Specifically, the image blur correction unit 150 monitors the position of the center of the image moved by the parallel movement of the correction member 1011. The image center is a point on the image where a light beam passing on the optical axis of the camera intersects with the imaging element surface in a state where the optical axis of the lens is not decentered. The image center position on the imaging element surface moves with the movement of the correction member 1011. In addition, the translation amount of the optical image and the translation amount of the center of the image are naturally equivalent. When high accuracy is not required, the image blur correction unit 150 may directly output control information of the correction member 1011.

<Vibration isolation>
First, FIG. 3A illustrates a state of optical image stabilization due to parallel movement of a lens unit of an optical system. An optical image from the subject 106 is formed on the surface of the image sensor 103 by the optical system 101. A broken line indicates an optical path when the correction member 1011 has no image blur correction. On the other hand, a solid line indicates an optical path when the correction member 1011 moves upward due to image blur correction. The subject image is formed at the center of the image sensor 103 by the image blur correction. In other words, the state shown by the solid line in FIG. 3A is, as shown in FIG. 3B, the image of the subject (dotted line) formed on the lower peripheral portion of the image sensor without image blur correction. Is formed in the center of the image sensor by image blur correction (movement of the correction member). FIG. 3B shows a change in position of an optical image on the image sensor due to image blur correction. The illustration of the broken line is the position of the image before image blur correction, and the illustration of the solid line is the position of the image after image blur correction. An X mark 301 indicates the position of the image center before the image blur correction, and a black circle 302 indicates the position of the image center after the image blur correction. The image center is a point on the image where a light ray passing on the optical axis of the camera intersects with the imaging element surface in a state where the optical axis of the lens is not decentered. The center of the image moves in response to the movement of the correction member 1011. That is, the center of the image moves in accordance with the movement of the image due to the image blur correction, even if the image center is coincident with the center coordinates of the image when the image blur correction is not performed.

  FIG. 3C illustrates a case where the correction member 1011 is included in the image sensor 103 (a case where the correction member 1011 moves the image sensor 103). The correction member 1011 is moved by the image blur correction, whereby the optical image is moved to the center of the imaging area as in FIG. FIG. 3D shows a captured image 303 in the situation shown in FIG. An X mark 304 indicates the position of the center of the image without image blur correction, and a black circle 305 indicates the position of the center of the image during image blur correction. Although the correction member 1011 is moved in the opposite direction to the case of FIG. 3A, the effect obtained as shown in FIG. 3D is the same as that of FIG. 3C. In other words, whether the correction member 1011 is included in the imaging optical system 101 or the image sensor 103 does not cause a substantial difference in the correction effect. Therefore, in the following description, it is not distinguished whether the correction member 1011 is included in the imaging optical system 101 or the imaging element 103.

  The movement of the optical image with respect to the image sensor 103 causes a change in the correspondence between pixels and conversion coefficients. That is, if there is image blur correction, the conversion coefficient map without image blur correction as shown in FIG. 4A cannot be used as it is. Therefore, the conversion coefficient calculation unit 14 changes the conversion coefficient map based on the image blur correction amount (movement amount of the optical image), and obtains a conversion coefficient appropriate for the pixel for which the defocus amount is calculated.

<Conversion coefficient determination processing>
In the case of using the image blur correction (anti-vibration mechanism) as described above, it is necessary to adjust the conversion coefficient map in the distance calculation processing. Hereinafter, the distance measurement calculation processing (distance information acquisition processing) in consideration of image blur correction will be described with reference to the flowchart illustrated in FIG.

  In step S501 (pixel selection processing), the arithmetic processing unit 104 selects the position on the image sensor of the pixel for which distance calculation is to be performed. In the following description, the pixel selected in step S501 is referred to as a target pixel.

  In step S502 (image blur correction amount acquisition processing), the image blur correction amount acquisition unit 13 acquires the image blur correction amount from the image blur correction unit 150. As described above, the image blur correction amount is information related to the amount of movement of the image with respect to the image sensor. The image blur correction amount may be a movement amount of the correction member 1011.

In step S503 (conversion coefficient determination processing), the conversion coefficient calculation unit 14 determines a conversion coefficient of the target pixel (a coefficient for converting an image shift amount into a defocus amount as shown in Expression (3)). The conversion coefficient calculation unit 14 corrects the conversion coefficient map according to the optical image moved by the image blur correction based on the image blur correction amount. The conversion coefficient calculation unit 14 determines a conversion coefficient of the target pixel from the corrected conversion coefficient map. The processing in step S503 can be regarded as a conversion coefficient correction processing for correcting a conversion coefficient, or as distance information correction processing for correcting a defocus amount (distance information).

  It is preferable that the method of correcting the conversion coefficient map be changed depending on the magnitude of the image blur correction amount. In the present embodiment, the processing is different for each case where the image blur correction amount is (1) small, (2) slightly large, and (3) large. In the following, the processing in each case will be described first, and then the threshold value of the image blur correction amount, which will be a reference for classification, will be described.

[1. When the amount of image blur correction is small]
When the image blur correction amount is small, the conversion coefficient map relating to the state where the image blur correction amount is 0 may be translated based on the movement amount of the pixel on the imaging surface. FIG. 4A shows a conversion coefficient map for a state where the image blur correction amount is 0, and FIG. 4B shows a conversion coefficient map after correction. In this example, the image blur correction amount (x, y) = (1, 0). In this case, assuming that the corrected conversion coefficient map is K '(x, y), K' (x, y) = K (x + 1, y).

  Since the amount of image blur correction changes continuously, the amount of movement of the conversion coefficient map can be a sub-pixel value. In that case, the conversion coefficient map may be re-created using interpolation. At this time, the conversion coefficient calculation unit 14 realizes the re-creation of the map by backward mapping which performs sampling and interpolation of the input map data based on the output map coordinates so that no defect occurs in the data of the output map. The interpolation method is not particularly limited. The conversion coefficient calculation unit 14 performs an interpolation process using a pixel value near the sampling coordinates on the input map calculated according to the interpolation method. For the interpolation processing, for example, bilinear interpolation processing for performing linear interpolation using four neighbors, bicubic interpolation processing for performing cubic interpolation using sixteen neighbors, and the like can be used.

Referring to FIG. 5C, bilinear interpolation will be described as a typical example. A black circle 601 indicates a corresponding point (sampling point) of a certain pixel on the output map on the input map. The x and y coordinates of a sampling point are generally non-integers. The conversion coefficient calculation unit 14 obtains output map data by bilinear interpolation using four input map data (data indicated by white circles) around the sampling coordinates. More specifically, the conversion coefficient calculation unit 14 calculates four neighbors from the memory, that is, ([x], [y]), ([x + 1], [y]), ([x], [y + 1]), ([x + 1 , [Y + 1]) are read. [X] represents an integer part of the value x. Then, the conversion coefficient calculator 14 calculates the map value of the output map according to the following equation.

  Here, K (x, y) is an input map (that is, a conversion coefficient map in which the image blur correction amount is 0), and K ′ (x, y) is an output map (that is, a conversion coefficient map in consideration of the image blur correction). Map).

  By sequentially performing the above processing, the conversion coefficient map can be interpolated. However, in practice, it is not necessary to re-create the entire conversion coefficient map, and it is sufficient to obtain only the conversion coefficient of the position of the target pixel acquired in step S501 (pixel selection processing).

[2. When the amount of image blur correction is slightly large]
When the image blur correction amount is slightly increased, the movement of the correction member 1011 exerts an influence of eccentric distortion on the parallel movement of the optical image. Therefore, the image does not simply move in parallel, but also undergoes geometric deformation such as scaling and tilt. However, when the movement of the optical image due to the image blur correction is not so large, the change in the light amount is small. Therefore, the conversion coefficient corresponding to the movement of the optical image is approximated by geometric conversion (generally, projective conversion) of the conversion coefficient map. You can recreate the map. That is, the conversion coefficient calculation unit 14 deforms the conversion coefficient map when the image blur correction amount is 0 in accordance with the translational movement of the optical image and the movement of enlargement / reduction and tilt.

[3. When the amount of image blur correction is large]
When the amount of image blur correction is even larger, a change in the amount of light due to geometric deformation of the optical image cannot be ignored. In this case, if not only the zoom state of the optical system 101, the object distance, and the aperture value, but also a conversion coefficient map for the image height for each of the x and y parameters of the image blur correction amount is created and held in advance. It is possible. The conversion coefficient calculation unit 14 may obtain a conversion coefficient map that satisfies the condition and determine the conversion coefficient to be applied to the target pixel.

  Alternatively, the conversion coefficient map may be modified according to the image blur correction amount. For this purpose, for example, a change in the conversion coefficient at each image position due to a change in the image blur correction amount is stored as a coefficient (fitting parameter) of a fitting function of the hyperplane. The conversion coefficient calculation unit 14 can also obtain a conversion coefficient map corresponding to the image blur correction amount by applying a fitting function to the conversion coefficient map and deforming it.

  Also, a conversion coefficient map is created and stored in advance for a plurality of image blur correction amounts, and the above-described processing (1) or (2) is performed based on the conversion coefficient map closest to the actual image blur correction amount. Thus, the conversion coefficient applied to the target pixel may be determined. That is, the conversion coefficient map corresponding to the position in the image plane for a plurality of predetermined image blur correction amounts is stored in the memory, and the conversion coefficient calculation unit 14 determines the conversion coefficient closest to the actual image blur correction amount. The conversion coefficient applied to the target pixel may be determined by translating or projecting the map.

[Criteria for classification]
As described above, it is preferable to make the processing different depending on the magnitude of the image blur correction amount. Here, the threshold value of the amount of image blur, which is a reference for classification, differs depending on the imaging optical system 101, and may be determined by an appropriate method. For example, when various image blur correction amounts are applied to various subjects with known distances, distance information is obtained by the above three processes. The image blur correction amount in which the distance measurement error by the first method is equal to or larger than the allowable range can be determined as a first threshold value for distinguishing between a case where the image blur correction amount is small and a case where the image blur correction amount is slightly large. . Similarly, the image blur correction amount in which the distance measurement error by the second method is equal to or larger than the allowable range is determined by a second threshold value for distinguishing between a case where the image blur correction amount is slightly large and a case where the image blur correction amount is large. Can be determined as

  The conversion coefficient calculation unit 14 performs the first method when the image blur correction amount is equal to or less than the first threshold, the second method when the image blur correction amount is larger than the first threshold and equal to or less than the second threshold, and When it is larger than the threshold value, the conversion coefficient is obtained according to the third method. It is technically equivalent to change the processing when the image blur correction amount is equal to or less than the threshold value and when the image blur correction amount is larger than the threshold value and to change the processing when the image blur correction amount is smaller than the threshold value and when the image blur correction amount is equal to or more than the threshold value. Therefore, instead of determining whether or not the image blur correction amount is equal to or less than the threshold value, it may be determined whether the image blur correction amount is smaller than the threshold value.

  The image shift amount calculation processing in step S504 is the same processing as step S201 in FIG. In step S505 (distance calculation processing), the distance calculation unit 15 calculates the defocus amount from the image shift amount using Expression (3) using the value of the conversion coefficient acquired in step S503.

The conversion coefficient map for the state where the image blur correction amount is 0 can be determined as follows, for example. First, a predetermined distance measurement condition such as the state of the imaging optical system (focal length, aperture, focus distance, defocus amount) and the position (image height) of a distance measurement pixel on the image sensor 103 is at a known distance. Shoot various subjects. A conversion coefficient map is calculated from a signal acquired from each subject by an image shift amount and a predetermined calculation formula. Further, the conversion coefficient is adjusted so that the actual distance of each subject is shorter than the distance obtained from the image shift amount and the conversion coefficient. Alternatively, the conversion coefficient map may be determined by performing a similar method by numerical simulation based on the design values of the imaging optical system 101 and the distance measurement device 102.

(Embodiment 2)
The image shift amount may not become zero even at the best focus position where the defocus amount should become zero due to the influence of the tilt of the image sensor surface, spherical aberration, axial chromatic aberration, and the like. Also, the best focus position may differ depending on the RGB pixel and the image height. In the distance measurement calculation process, this effect can be corrected by using the coefficient M as in Expression (5).

  In this case, the correction value M is also different depending on the image height. That is, in order to obtain a small error in the defocus amount in consideration of the deviation of the best focus position due to the image height, it is necessary to store the coefficient K relating to the base line length and the correction amount M of the best focus position in the memory 105. There is. In the present embodiment, two-element vector parameters consisting of a coefficient K and a coefficient M are stored in the memory 105 as a two-dimensional table corresponding to the pixel position as shown in FIG. That is, in the present embodiment, the vector parameter (K, M) corresponds to a conversion coefficient, and a table T (x, y) = (K (x, y), M) storing the coefficient K and the coefficient M for each pixel position. (X, y)) corresponds to the conversion coefficient map.

  FIG. 7 shows a flowchart of the distance measurement calculation process in the present embodiment. As shown in FIG. 7, the processing content is the same as in the first embodiment.

  In the present embodiment, in step S603 (conversion coefficient determination processing), processing for determining a conversion coefficient (K, M) corresponding to the target pixel selected in step S501 is performed. Specific processing is substantially the same as in the first embodiment. That is, the conversion coefficient map when the image blur correction amount is 0 may be corrected according to the image blur correction amount acquired in step S502. Also in this case, similarly to the first embodiment, it is preferable to correct the conversion coefficient map by different processing according to the magnitude of the image blur correction amount.

  In step S605 (distance calculation processing), the distance calculation unit 15 calculates the defocus amount from the image shift amount by using Expression (5) using the value of the conversion coefficient acquired in step S603.

  The conversion coefficient map (K, M) corresponding to the state where the image blur correction amount is 0 can be determined as follows, for example. First, a predetermined distance measurement condition such as the state of the imaging optical system (focal length, aperture, focus distance, defocus amount) and the position (image height) of a distance measurement pixel on the image sensor 103 is at a known distance. Shoot various subjects. A conversion coefficient map (K, M) is calculated from a signal acquired from each subject by an image shift amount and a predetermined calculation formula. The conversion coefficients (K, M) are adjusted so that the actual distance of each subject and the distance obtained from the image shift amount and the conversion coefficients (K, M) become shorter. Alternatively, the conversion coefficient map (K, M) may be determined by performing a similar method by numerical simulation based on the design values of the imaging optical system 101 and the distance measuring device 102.

(Embodiment 3)
In the first and second embodiments, it is basically assumed that there is no vignetting or aberration due to the lens barrel. However, in a normal imaging optical system, a so-called vignetting, in which a light beam is cut off by a lens frame, occurs due to a demand for miniaturization of an imaging lens, and the light beam that has passed through the inside of the diaphragm is not guided to the image sensor. Due to this effect, the value of the base line length W, which is the distance between the centers of gravity of the transmittance distribution on the pupil, and the associated conversion coefficient K also have different values depending on the image height. In addition, as the defocus calculation pixel becomes a peripheral pixel, the image difference between the A image and the B image increases, and the necessity of taking this into account increases.

  FIG. 8 is a top view of a main part of the image sensor 103. Here, an image sensor region 1032 and an image sensor region 1033 are set with a line segment 1031 passing through the center of the image sensor 103 and perpendicular to a direction connecting the center points of the photoelectric conversion unit 1101 and the photoelectric conversion unit 1102 as a boundary. In the imaging element region 1032 (second imaging element region), the photoelectric conversion unit 1102 that receives a light beam that has passed through the second pupil region is a first photoelectric conversion unit, and the photoelectric conversion unit 1101 is a second photoelectric conversion unit. And On the other hand, in a region 1033 (first imaging element region), the photoelectric conversion unit 1101 that receives a light beam that has passed through the first pupil region is a first photoelectric conversion unit, and the photoelectric conversion unit 1102 is a second photoelectric conversion unit. And

  FIG. 9A illustrates a pupil transmittance distribution on the exit pupil 130 corresponding to the photoelectric conversion unit 1102 in the distance measurement pixel 110 arranged near the center of the image sensor 103, and corresponds to the second pupil region. . The blacker the transmittance is higher, and the whiter the transmittance is lower. Similarly, FIG. 9B shows a pupil transmittance distribution on the exit pupil 130 corresponding to the photoelectric conversion unit 1101 in the ranging pixels 110 arranged near the center of the image sensor 103.

  FIG. 9C shows the transmittance distribution in the x-axis cross section of the distance measurement pixel 110 near the center of the image sensor 103, where the horizontal axis is the x-axis coordinate and the vertical axis is the transmittance. The solid line is the transmittance distribution corresponding to the photoelectric conversion unit 1102 (corresponding to the second pupil region), and the dotted line is the transmittance distribution corresponding to the photoelectric conversion unit 1101 (corresponding to the first pupil region). The pupil transmittance distribution depends on the positional relationship between the photoelectric conversion unit, the microlens and the exit pupil, and the light propagation conditions such as aberration, diffraction of the microlens, and light scattering and absorption in the optical path from the entrance surface of the image sensor to the photoelectric conversion unit. Decided.

  FIG. 9D illustrates a pupil transmittance distribution on the exit pupil 130 corresponding to the photoelectric conversion unit 1102 in the distance measurement pixel 110 in the imaging element region 1032, and corresponds to a second pupil region. FIG. 9E shows a pupil transmittance distribution on the exit pupil 130 corresponding to the photoelectric conversion unit 1101 in the distance measurement pixel 110 in the imaging element region 1032, and corresponds to the first pupil region. FIG. 9F shows the transmittance distribution in the x-axis cross section of the distance measurement pixel 110 in the imaging element region 1032.

  In general, at the peripheral image height, so-called vignetting occurs in which a light beam is cut off by the lens frame due to a demand for downsizing of the imaging lens, and all the light beam that has passed through the inside of the diaphragm is not guided to the image sensor. Since vignetting occurs from one side on the pupil, the amount of change in transmission efficiency varies depending on the shape of the original transmittance distribution. As shown in FIG. 9D, when the region 130a where vignetting occurs is a region where the original transmittance is high, the amount of decrease in transmission efficiency is large. On the other hand, as shown in FIG. 9E, when the area 130a where vignetting occurs is an area where the original transmittance is low, the amount of decrease in transmission efficiency is small. Therefore, in the ranging pixels 110 of the imaging element region 1032, as the image height increases, the transmittance distribution of the second pupil region is smaller than the transmittance distribution of the first pupil region. The shape changes greatly due to the loss. Therefore, the position of the center of gravity changes, and the base line length changes in the direction of shortening.

FIG. 9G illustrates a pupil transmittance distribution on the exit pupil 130 corresponding to the photoelectric conversion unit 1102 in the distance measurement pixel 110 in the imaging element region 1033, and corresponds to a second pupil region. FIG. 9H illustrates a pupil transmittance distribution on the exit pupil 130 corresponding to the photoelectric conversion unit 1101 in the distance measurement pixel 110 in the imaging element region 1033, and corresponds to the first pupil region. FIG. 9I shows the transmittance distribution in the x-axis cross section of the distance measurement pixels in the image sensor region 1033.

  As in the image sensor region 1032, in the ranging pixels 110 in the image sensor region 1033, as the image height increases, the transmittance distribution of the first pupil region is more blurred than the transmittance distribution of the second pupil region. The shape changes greatly due to the loss compared to the case where there is no gap. Therefore, the position of the center of gravity changes, and the base line length changes in the direction of shortening.

  As described above, the distance between the centers of gravity, which is the length between the positions of the centers of gravity of the pupil sensitivity distributions of the photoelectric conversion units, differs depending on the image height (pixel position), and the value of the base line length W also differs depending on the image height. Become. Therefore, in order to perform highly accurate ranging, it is necessary to use the value of the base line length according to the image height in the distance calculation processing using Expression (2) or Expression (5).

  As described above, the amount of change in the value of the received light amount distribution according to the position of the pixel on the image sensor corresponds to the base line length W or the related conversion coefficient.

<Image correction>
If there is vignetting of the light beam due to the frame of the imaging lens or the like, the aperture functions of the optical systems that form the A image and the B image are different, so that the A image and the B image have different shapes, and the distance measurement accuracy deteriorates. . Therefore, an image correction process is performed using a known method. A ranging method using basic image correction processing when image blur correction is OFF is disclosed in Japanese Patent Application Laid-Open No. 2013-222183 (Patent Document 3).

  The image correction filter is created based on the image correction function. The image correction function is, for example, a line image distribution function corresponding to the first pupil region or the second pupil region. Using the A image and the B image and the image correction filters La ′ and Lb ′, an A ′ image and a B ′ image whose image shapes are corrected are created. The image correction filter Lb '[x] is convolution-integrated with the one-dimensional signal A [x] of the A image, thereby creating A' [x]. Similarly, for the B image, the image correction filter La ′ (x) is convolution-integrated with the one-dimensional signal B [x] of the B image to create B ′ [x]. The image correction filter is composed of, for example, 9 × 1 multidimensional vector filter coefficients (f1,..., F9), and is calculated in advance according to the image height.

  However, since the corresponding image height of the image correction filter also moves in accordance with the movement of the optical image due to the image blur correction, the map must be corrected by performing a geometric transformation according to the image blur correction amount, similarly to the conversion coefficient. FIG. 10 shows an example of a flowchart of the distance measurement calculation process in the image correction process in consideration of the image blur correction.

  The pixel selection processing in step S701 and the image stabilization correction amount acquisition processing in step S702 are the same as steps S501 and S503 in the first embodiment, and a description thereof will not be repeated.

  In the conversion coefficient / image correction coefficient acquisition processing in step S703, the conversion coefficient is acquired by processing that is substantially the same as step S504 in the first embodiment or step S604 in the second embodiment. In the present embodiment, the image correction filter coefficient map associated with the image height is further geometrically deformed based on the image blur correction amount, and the image correction filter coefficient corresponding to the selected pixel is obtained from the converted image correction filter coefficient map. . In order to reduce the storage capacity in the memory, a change in the filter coefficient according to the image blur correction amount may be separately stored as a polynomial coefficient or the like, and the filter coefficient may be obtained by an operation using this polynomial. Thus, the number of saved image correction filter coefficient maps corresponding to the amount of image blur correction can be limited.

  The conversion coefficient and the filter coefficient when the image blur correction amount is 0 are stored in advance in the memory 105 for each imaging condition (F value, exit pupil distance) of the imaging optical system 101. FIG. 11 is a diagram showing how the conversion coefficient and the filter coefficient are stored in the memory 105 as a two-dimensional table corresponding to the pixel position. Here, T1 = (f1,..., Fn) represents a filter coefficient vector, and T2 = (K, M) represents a conversion coefficient vector. In step S703, the two-dimensional table corresponding to the pixel position is geometrically deformed according to the image blur correction amount, as in the second embodiment.

  In the image correction processing in step S704, the A ′ image and the B ′ image, which are images obtained by correcting the A image and the B image, are created using the image correction filter obtained in step S703. The image correction filter is created based on the image correction function. The image correction function is, for example, a line image distribution function corresponding to the first pupil region or the second pupil region. Using the A image and the B image and the image correction filters La ′ and Lb ′, an A ′ image and a B ′ image whose image shapes are corrected are created. The image correction filter Lb '[x] is convolution-integrated with the one-dimensional signal A [x] of the A image, thereby creating A' [x]. Similarly, for the B image, the image correction filter La ′ (x) is convolution-integrated with the one-dimensional signal B [x] of the B image to create B ′ [x].

  The image shift amount calculation processing in step S705 is the same as step S502 in the first embodiment except that the A and B images after the image correction processing (that is, the A ′ image and the B ′ image) are used. The distance calculation processing in step S706 is the same as the distance calculation processing in step S505 in the first embodiment or S605 in the second embodiment, and uses the conversion coefficient value acquired in the conversion coefficient acquisition processing in step S705 to obtain the equation (2). Alternatively, the distance measurement calculation processing according to the equation (5) is performed.

  The conversion coefficient map (K, M) corresponding to the state where the image blur correction amount is 0 can be determined as follows, for example. First, a predetermined distance measurement condition such as the state of the imaging optical system (focal length, aperture, focus distance, defocus amount) and the position (image height) of a distance measurement pixel on the image sensor 103 is at a known distance. Shoot various subjects. A conversion coefficient map (K, M) is calculated from a signal acquired from each subject by an image shift amount and a predetermined calculation formula. The conversion coefficients (K, M) are adjusted so that the actual distance of each subject and the distance obtained from the image shift amount and the conversion coefficients (K, M) become shorter. Alternatively, the conversion coefficient map (K, M) may be determined by performing a similar method by numerical simulation based on the design values of the imaging optical system 101 and the distance measuring device 102.

  The image correction filter corresponding to the state where the image blur correction amount is 0 can be created in advance by a numerical simulation based on design values of the imaging optical system 101 and the distance measurement device 102. It is necessary to create an image correction filter in advance under predetermined ranging conditions such as the state of the imaging optical system (focal length, aperture, focus distance, defocus amount) and the position of a ranging pixel on the image sensor 103 (image height). Just fine.

  FIG. 12 shows an example of the image correction filter. In FIG. 12A, a filter Fy1301 (first filter) has one cell number in the x direction and Ay (Ay is an integer of 2 or more) in the y direction, and a cell 1303 has a cell value (filter value). Having. 12B, a filter Fx1302 (second filter) has Ax in the x direction and 1 (Ax is an integer of 2 or more) in the y direction, and a cell 1304 has a cell value (filter value). Having. Each cell corresponds to one pixel of the image signal (S101 or S102).

(Embodiment 4)
In the first to third embodiments, the conversion coefficient is corrected according to the image blur correction amount. In the present embodiment, not the conversion coefficient but the image shift amount is corrected according to the image blur correction amount. Since the defocus amount is obtained from the image shift amount and the conversion coefficient, the same effect can be obtained by correcting the image shift amount according to the image blur correction amount instead of correcting the conversion coefficient according to the image blur correction amount. Can be

  The distance measuring apparatus 102 according to the present embodiment stores a correction coefficient map in which a correction coefficient for correcting an image shift amount is stored for each pixel position in the memory 105.

  The basic flow of the distance measurement calculation processing in the present embodiment is the same as in the first embodiment. Therefore, the distance measurement calculation processing according to the present embodiment will be described in comparison with the first embodiment (the flowchart of FIG. 5B). The pixel selection processing (S501) and the image blur correction amount acquisition processing (S502) are the same as in the first embodiment. In the conversion coefficient acquisition process (S503), the value of the conversion coefficient included in the conversion coefficient map prepared in advance is used as it is. In the image shift amount calculation process (S504), first, an image shift amount is obtained as a shift amount that minimizes the correlation value S (k), as in the first embodiment. Thereafter, the correction coefficient map is adjusted according to the image blur correction amount, and the image shift amount is corrected using the correction coefficient included in the adjusted correction coefficient map. The adjustment processing of the correction coefficient map is the same as the adjustment processing of the conversion coefficient map in the first embodiment. In the distance calculation process (S505), the defocus amount is calculated according to the equation (2) or (3) using the conversion coefficient obtained in step S503 and the corrected image shift amount obtained in step S504. You.

(Other embodiments)
The object of the present invention can also be achieved by the following embodiments. That is, a storage or recording medium storing a program code of software for realizing the functions of the above-described embodiment (functions of the calculation means and the like) is supplied to the distance measuring device. Then, the computer (or CPU, MPU, or the like) of the arithmetic unit reads out the program code stored in the storage medium and executes the above function. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the program and the storage medium storing the program constitute the present invention.

  When the computer executes the readout program code, an operating system (OS) or the like running on the computer performs part or all of the actual processing based on the instructions of the program code. The case where the functions of the above-described embodiments are realized by the processing is also included in the present invention. Further, it is assumed that the program code read from the storage medium is written in a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instructions of the program code, the CPU or the like provided in the function expansion card or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing. Included in the invention. When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the flowcharts described above.

  Considering an application to a digital camera or the like, the present invention provides a so-called image pickup device that also performs distance detection using an image pickup unit of an image pickup device, rather than a distance measurement device dedicated to distance detection (used in a single-lens reflex camera or the like). It can be regarded as a device suitable for surface ranging. As described above, the arithmetic unit in the distance measuring apparatus of the present invention can be configured using an integrated circuit in which semiconductor elements are integrated, and includes an IC, an LSI, a system LSI, a micro processing unit (MPU), a central processing unit (CPU) or the like. When the arithmetic unit is configured by a micro processing unit, a central processing unit (CPU), or the like, the arithmetic unit can be regarded as a computer. The program of the present invention is installed in a computer of an imaging device including a predetermined imaging optical system, a predetermined imaging unit, and a computer, so that the imaging device can detect a distance with high accuracy. Can be. The program of the present invention can be distributed via the Internet in addition to the recording medium.

  Using the distance detected by the present invention, a distance distribution (distance map) corresponding to an image obtained by the imaging device can be generated. Also, since the blur amount of the subject in the image depends on the defocus amount, by performing a process based on the distance distribution on the obtained image, an arbitrary blur adding process, a refocusing process after shooting (an arbitrary Image processing such as processing for focusing on the position) can be appropriately performed.

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

14. Conversion coefficient calculator 15 Distance calculator 102 Distance measuring device

Claims (13)

Image blur correction means,
Based on a first image based on a light beam that has passed through a first pupil region of the imaging optical system and a second image based on a light beam that has passed through a second pupil region of the imaging optical system, a distance Distance information acquisition means for acquiring information;
A distance information correcting unit that corrects the distance information based on an image blur correction amount by the image blur correcting unit;
Equipped with a,
The distance information obtaining unit is configured to obtain an image shift amount between the first image and the second image, and the image shift amount from the image shift amount using a conversion coefficient corresponding to a pixel position. Second acquisition means for acquiring distance information,
The distance information correcting unit includes a third obtaining unit that obtains the conversion coefficient based on the image blur correction amount,
The third obtaining unit changes a method of obtaining the conversion coefficient according to the magnitude of the image blur correction amount,
Distance measuring device. The third obtaining unit changes a method of obtaining the conversion coefficient when the image blur correction amount is larger than a predetermined threshold,
The distance measuring device according to claim 1. A storage unit that stores a conversion coefficient map corresponding to a position in an image plane for a predetermined image blur correction amount,
The third obtaining unit obtains the conversion coefficient by geometrically converting the conversion coefficient map according to the image blur correction amount,
The distance measuring device according to claim 1 . The third obtaining means translates the conversion coefficient map when the image blur correction amount is smaller than a first threshold, and converts the conversion when the image blur correction amount is larger than the first threshold. Apply a projective transformation to the coefficient map,
The distance measuring device according to claim 3. When the image shift amount is r and the distance information is ΔL, the second obtaining unit obtains the distance information by ΔL = K × r,
The conversion coefficient is a coefficient K corresponding to a position of a pixel.
The distance measuring device according to claim 1 . When the image shift amount is r and the distance information is ΔL, the second obtaining unit obtains the distance information by ΔL = K × r + M,
The conversion coefficient includes a coefficient K and a coefficient M corresponding to the position of a pixel.
The distance measuring device according to claim 1 . Image blur correction means,
Based on a first image based on a light beam that has passed through a first pupil region of the imaging optical system and a second image based on a light beam that has passed through a second pupil region of the imaging optical system, a distance Distance information acquisition means for acquiring information;
A distance information correcting unit that corrects the distance information based on an image blur correction amount by the image blur correcting unit;
Image correction means for determining an image correction filter based on the amount of image blur correction by the image blur correction means, and performing image correction processing of the first image and the second image using the image correction filter ,
Bei to give a,
The distance information obtaining unit is configured to obtain an image shift amount between the first image and the second image, and the image shift amount from the image shift amount using a conversion coefficient corresponding to a pixel position. Second acquisition means for acquiring distance information,
The second obtaining means obtains the distance information from the first image and the second image after the image correction processing by the image correcting means ,
Distance measuring device. A storage unit that stores a filter coefficient map of an image correction filter according to a position in an image plane for a predetermined image blur correction amount,
The image correction unit geometrically transforms the filter coefficient map according to the image blur correction amount, and performs the image correction processing using an image correction filter obtained from the converted filter coefficient map.
A distance measuring device according to claim 7. The image blur correction means is to move a part of the lens or the imaging device of the imaging optical system,
The image blur correction amount is a movement amount of the part of the lenses or the image sensor by the image blur correction unit.
The distance measuring device according to claim 1. An image sensor;
A distance measuring device according to any one of claims 1 to 9,
An imaging device comprising: Based on a first image based on a light beam that has passed through a first pupil region of the imaging optical system and a second image based on a light beam that has passed through a second pupil region of the imaging optical system, a distance A distance information obtaining step of obtaining information;
An obtaining step of obtaining an image blur correction amount by the image blur correcting means,
A distance information correction step of correcting the distance information based on the image blur correction amount,
Only including,
The distance information obtaining step is a first obtaining step of obtaining an image shift amount between the first image and the second image, and the image shift amount is calculated from the image shift amount using a conversion coefficient corresponding to a pixel position. A second acquisition step of acquiring distance information,
The distance information correcting step includes a third obtaining step of obtaining the conversion coefficient based on the image blur correction amount,
In the third obtaining step, a method of obtaining the conversion coefficient is changed according to the magnitude of the image blur correction amount,
Distance measurement method. Based on a first image based on a light beam that has passed through a first pupil region of the imaging optical system and a second image based on a light beam that has passed through a second pupil region of the imaging optical system, a distance A distance information obtaining step of obtaining information;
An obtaining step of obtaining an image blur correction amount by the image blur correcting means,
A distance information correction step of correcting the distance information based on the image blur correction amount,
Determine an image correction filter based on the image blur correction amount, an image correction step of performing image correction processing of the first image and the second image using the image correction filter,
Including
The distance information obtaining step is a first obtaining step of obtaining an image shift amount between the first image and the second image, and the image shift amount is calculated from the image shift amount using a conversion coefficient corresponding to a pixel position. A second acquisition step of acquiring distance information,
In the second obtaining step, the distance information is obtained from the first image and the second image after the image correction processing by the image correction step,
Distance measurement method. A program for causing a computer to execute each step of the method according to claim 11 .

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