JP5978738B2 - Image processing apparatus, imaging apparatus, and image processing program - Google Patents

Description

  The present invention relates to an image processing device, an imaging device, and an image processing program.

There is known a stereo imaging device that acquires a stereo image composed of a right-eye image and a left-eye image using two photographing optical systems. Such a stereo imaging device causes parallax to occur in two images obtained by imaging the same subject by arranging two imaging optical systems at regular intervals.
[Prior art documents]
[Patent Literature]
[Patent Document 1] JP-A-8-47001

  The amount of blur and the amount of parallax in the image for the right eye and the image for the left eye are integrally determined by the focus position and aperture value set by the imaging optical system. However, there are cases where it is desired to independently change the parallax amount while maintaining the blur amount.

The image processing apparatus according to the first aspect of the present invention includes reference image data generated by capturing the same scene, first parallax image data having a first parallax in one direction with respect to a subject image of the reference image data, And an image data acquisition unit that acquires second parallax image data having a second parallax in a direction opposite to one direction, a reference pixel value at a target pixel position of the reference image data, and a target pixel position of the first parallax image data And the second parallax luminance value at the target pixel position of the second parallax image data are extracted, and the calculation formula P ₃ −P ₀ = (1 / 2−C) (P ₂ −P ₁ ) (P ₀ : reference pixel value, P ₁ : first parallax luminance value, P ₂ : second parallax luminance value, P ₃ : third parallax pixel value, C: real number (where C ≠ 0, 0.5, 1 )), The first parallax and the second parallax with respect to the subject image A calculation unit that calculates a third parallax pixel value having a different third parallax, and a plurality of third parallax pixel values calculated by the calculation unit by sequentially moving the target pixel position with respect to the image area in the reference image data And an image data generation unit for generating third parallax image data.

  An image pickup apparatus according to a second aspect of the present invention is an image pickup apparatus including an image pickup element that picks up an image of the same scene and the image processing apparatus described above, and the image data acquisition unit includes reference image data output by the image pickup element, First parallax image data and second parallax image data are acquired.

The image processing program according to the third aspect of the present invention includes reference image data generated by capturing the same scene, first parallax image data having a first parallax in one direction with respect to a subject image of the reference image data, And an image data acquisition step for acquiring second parallax image data having a second parallax in another direction opposite to one direction, and the reference image data while sequentially moving the target pixel position with respect to the image area in the reference image data The reference pixel value at the target pixel position, the first parallax luminance value at the target pixel position of the first parallax image data, and the second parallax luminance value at the target pixel position of the second parallax image data are extracted, and the calculation formula P _{3 -P 0 = (1/2-} C) (P 2 -P 1) (P 0: reference pixel value, _{P 1:} first parallax luminance value, _{P 2:} the second parallax luminance value, _{P 3:} third parallax Pixel value, C: Real number (Where C ≠ 0, 0.5, 1)), a calculation step for sequentially calculating a third parallax pixel value having a third parallax different from the first parallax and the second parallax for the subject image, and a calculation step Using the plurality of third parallax pixel values calculated by the above, the computer executes an image data generation step for generating third parallax image data.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

It is a figure explaining the structure of the digital camera which concerns on embodiment of this invention. It is the schematic showing the cross section of the image pick-up element which concerns on embodiment of this invention. It is the schematic showing a mode that a part of imaging device was expanded. It is a conceptual diagram explaining the relationship between a parallax pixel and a to-be-photographed object. It is a conceptual diagram explaining the process which produces | generates a parallax image. It is a figure explaining a Bayer arrangement. It is a figure explaining the variation in case there are two kinds of parallax pixels about allocation of parallax pixels to a Bayer arrangement. It is a figure which shows an example of a variation. It is a figure which shows an example of another variation. It is a figure which shows an example of another variation. It is a figure explaining other color filter arrangement | sequences. It is a figure which shows an example of the arrangement | sequence of W pixel and a parallax pixel. It is a figure explaining a plane separation process. It is a figure explaining the interpolation process of plane data. It is a figure explaining the data structure of a RAW image data set. It is a figure explaining the concept of defocusing. It is a figure explaining the concept of parallax pixel defocusing. It is a figure which shows the light intensity distribution of a parallax pixel and a parallax pixel. It is a figure which shows the light intensity distribution for demonstrating the concept of adjustment parallax amount. It is a figure explaining the production | generation process of color parallax plane data. It is a figure explaining the change of the light intensity distribution of RGB. It is a processing flow until it produces | generates parallax color image data. It is a figure explaining a preferable opening shape. It is a figure which shows the light intensity distribution for demonstrating the concept of adjustment parallax amount. It is a figure explaining the production | generation process of color parallax plane data. It is a figure explaining the change of the light intensity distribution of RGB. It is a figure explaining the plane separation process in the image pick-up element 100 which employ | adopts another repeating pattern. It is a figure explaining the data structure of the RAW image data set in the image pick-up element 100 which employ | adopts another repeating pattern.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  The digital camera according to the present embodiment, which is a form of the image processing apparatus and the imaging apparatus, is configured to be able to generate images with a plurality of viewpoints for one scene by one shooting. Each image having a different viewpoint is called a parallax image.

  FIG. 1 is a diagram illustrating the configuration of a digital camera 10 according to an embodiment of the present invention. The digital camera 10 includes a photographic lens 20 as a photographic optical system, and guides a subject light beam incident along the optical axis 21 to the image sensor 100. The photographing lens 20 may be an interchangeable lens that can be attached to and detached from the digital camera 10. The digital camera 10 includes an image sensor 100, a control unit 201, an A / D conversion circuit 202, a memory 203, a drive unit 204, an image processing unit 205, a memory card IF 207, an operation unit 208, a display unit 209, an LCD drive circuit 210, and an AF. A sensor 211 is provided.

  As shown in the figure, the direction parallel to the optical axis 21 toward the image sensor 100 is defined as the z-axis plus direction, the direction toward the front of the drawing in the plane orthogonal to the z-axis is the x-axis plus direction, and the upward direction on the drawing is y. The axis is defined as the plus direction. In the following several figures, the coordinate axes are displayed so that the orientation of each figure can be understood with reference to the coordinate axes of FIG.

  The taking lens 20 is composed of a plurality of optical lens groups, and forms an image of a subject light flux from the scene in the vicinity of its focal plane. In FIG. 1, for convenience of explanation, the photographic lens 20 is represented by a single virtual lens arranged in the vicinity of the pupil. The image sensor 100 is disposed near the focal plane of the photographic lens 20. The image sensor 100 is an image sensor such as a CCD or CMOS sensor in which a plurality of photoelectric conversion elements are two-dimensionally arranged. The image sensor 100 is controlled in timing by the drive unit 204, converts the subject image formed on the light receiving surface into an image signal, and outputs the image signal to the A / D conversion circuit 202.

  The A / D conversion circuit 202 converts the image signal output from the image sensor 100 into a digital image signal and outputs the digital image signal to the memory 203. The image processing unit 205 performs various image processing using the memory 203 as a work space, and generates image data. In particular, the image processing unit 205 includes a pixel value extracting unit 231 that extracts a pixel value from the target pixel position of the color image data, a luminance value extracting unit 232 that extracts a luminance value from the target pixel position of the parallax image data, and the extracted pixel value. And a luminance value are used to calculate a pixel value as color image data at the target pixel position. Details of each processing will be described later.

  The image processing unit 205 also has general image processing functions such as adjusting image data according to the selected image format. The generated image data is converted into a display signal by the LCD drive circuit 210 and displayed on the display unit 209. The data is recorded on the memory card 220 attached to the memory card IF 207.

  The AF sensor 211 is a phase difference sensor in which a plurality of distance measuring points are set for the subject space, and detects the defocus amount of the subject image at each distance measuring point. A series of shooting sequences is started when the operation unit 208 receives a user operation and outputs an operation signal to the control unit 201. Various operations such as AF and AE accompanying the imaging sequence are executed under the control of the control unit 201. For example, the control unit 201 analyzes the detection signal of the AF sensor 211 and executes focus control for moving a focus lens that constitutes a part of the photographing lens 20.

  Next, the configuration of the image sensor 100 will be described in detail. FIG. 2 is a schematic diagram showing a cross section of the image sensor according to the embodiment of the present invention. FIG. 2A is a schematic cross-sectional view of the image sensor 100 in which the color filter 102 and the aperture mask 103 are separately formed. FIG. 2B is a schematic cross-sectional view of an image pickup device 120 including a screen filter 121 in which a color filter portion 122 and an opening mask portion 123 are integrally formed as a modification of the image pickup device 100.

  As shown in FIG. 2A, the image sensor 100 is configured by arranging a micro lens 101, a color filter 102, an aperture mask 103, a wiring layer 105, and a photoelectric conversion element 108 in this order from the subject side. The photoelectric conversion element 108 is configured by a photodiode that converts incident light into an electrical signal. A plurality of photoelectric conversion elements 108 are two-dimensionally arranged on the surface of the substrate 109.

  An image signal converted by the photoelectric conversion element 108, a control signal for controlling the photoelectric conversion element 108, and the like are transmitted and received through the wiring 106 provided in the wiring layer 105. In addition, an opening mask 103 having openings 104 provided in one-to-one correspondence with each photoelectric conversion element 108 is provided in contact with the wiring layer. As will be described later, the opening 104 is shifted for each corresponding photoelectric conversion element 108 so that the relative position is precisely determined. As will be described in detail later, parallax occurs in the subject light beam received by the photoelectric conversion element 108 by the action of the opening mask 103 including the opening 104.

  On the other hand, the aperture mask 103 does not exist on the photoelectric conversion element 108 that does not generate parallax. In other words, it can be said that the aperture mask 103 having the aperture 104 that does not limit the subject luminous flux incident on the corresponding photoelectric conversion element 108, that is, allows the entire effective luminous flux to pass therethrough is provided. Although no parallax is generated, the aperture 107 formed by the wiring 106 defines the subject luminous flux that is incident, so the wiring 106 is regarded as an aperture mask that allows the entire effective luminous flux that does not cause parallax to pass. You can also. The opening mask 103 may be arranged separately and independently corresponding to each photoelectric conversion element 108, or may be formed collectively for a plurality of photoelectric conversion elements 108 in the same manner as the manufacturing process of the color filter 102. .

  The color filter 102 is provided on the opening mask 103. The color filter 102 is a filter provided in a one-to-one correspondence with each photoelectric conversion element 108, which is colored so as to transmit a specific wavelength band to each photoelectric conversion element 108. In order to output a color image, it is only necessary to arrange at least two types of color filters that are different from each other. However, in order to obtain a higher quality color image, it is preferable to arrange three or more types of color filters. These color filters can be said to be primary color filters for generating a color image. The primary color filter combination is, for example, a red filter (R filter) that transmits the red wavelength band, a green filter (G filter) that transmits the green wavelength band, and a blue filter (B filter) that transmits the blue wavelength band. As will be described later, these color filters are arranged in a lattice pattern corresponding to the photoelectric conversion elements 108.

  The microlens 101 is provided on the color filter 102. The microlens 101 is a condensing lens for guiding more incident subject light flux to the photoelectric conversion element 108. The microlenses 101 are provided in a one-to-one correspondence with the photoelectric conversion elements 108. In consideration of the relative positional relationship between the pupil center of the taking lens 20 and the photoelectric conversion element 108, the optical axis of the microlens 101 is shifted so that more subject light flux is guided to the photoelectric conversion element 108. It is preferable. Furthermore, the arrangement position may be adjusted so that more specific subject light beam, which will be described later, is incident along with the position of the opening 104 of the opening mask 103.

  As described above, one unit of the aperture mask 103, the color filter 102, and the microlens 101 provided in one-to-one correspondence with each photoelectric conversion element 108 is referred to as a pixel. In particular, a pixel provided with the opening mask 103 that generates parallax is referred to as a parallax pixel, and a pixel that is not provided with the opening mask 103 that generates parallax is referred to as a non-parallax pixel. For example, when the effective pixel area of the image sensor 100 is about 24 mm × 16 mm, the number of pixels reaches about 12 million. In the image data generated from the output of the image sensor 100, a unit that can have an output value corresponding to the pixel of the image sensor 100 may be simply referred to as a pixel.

  Note that in the case of an image sensor with good light collection efficiency and photoelectric conversion efficiency, the microlens 101 may not be provided. In the case of a back-illuminated image sensor, the wiring layer 105 is provided on the side opposite to the photoelectric conversion element 108.

  There are various variations in the combination of the color filter 102 and the aperture mask 103. In FIG. 2A, the color filter 102 and the opening mask 103 can be integrally formed if the opening 104 of the opening mask 103 has a color component. In addition, when a specific pixel is a pixel that acquires luminance information of a subject, the corresponding color filter 102 may not be provided for the pixel. Or you may arrange | position the transparent filter which does not give coloring so that the substantially all wavelength band of visible light may be permeate | transmitted.

  In the present embodiment, the opening mask 103 and the wiring 106 are provided separately, but the wiring 106 may serve the function of the opening mask 103 in the parallax pixels. In other words, a defined aperture shape is formed by the wiring 106, the subject light beam is limited by the aperture shape, and only a specific partial light beam is guided to the photoelectric conversion element 108. In this case, the wiring 106 that forms the opening shape is preferably closest to the photoelectric conversion element 108 in the wiring layer 105.

Further, the opening mask 103 may be formed by a permeation blocking film provided to overlap the photoelectric conversion element 108. In this case, the opening mask 103 is formed, for example, by sequentially laminating a SiN film and a SiO ₂ film to form a permeation blocking film and removing a region corresponding to the opening 104 by etching.

  If the pixel from which luminance information is acquired is a parallax pixel, the configuration of the image sensor 120 shown in FIG. 2B can be employed. That is, the screen filter 121 in which the color filter part 122 that functions as a color filter and the opening mask part 123 having the opening 104 are integrally formed may be disposed between the microlens 101 and the wiring layer 105. it can.

  The screen filter 121 is formed by, for example, blue-green-red coloring in the color filter portion 122 and black in the opening mask portion 123 other than the opening portion 104. Since the image sensor 120 that employs the screen filter 121 has a shorter distance from the microlens 101 to the photoelectric conversion element 108 than the image sensor 100, the light collection efficiency of the subject light flux is high.

  Next, the relationship between the opening 104 of the opening mask 103 and the generated parallax will be described. FIG. 3 is a schematic diagram illustrating a state in which a part of the image sensor 100 is enlarged. Here, in order to simplify the explanation, the color arrangement of the color filter 102 is not considered until the reference is resumed later. In the following description that does not refer to the color arrangement of the color filter 102, it can be considered that the image sensor is a collection of only parallax pixels having the color filter 102 of the same color (including the case of being transparent). Therefore, the repetitive pattern described below may be considered as an adjacent pixel in the color filter 102 of the same color.

  As shown in FIG. 3, the opening 104 of the opening mask 103 is provided so as to be relatively shifted with respect to each pixel. In the adjacent pixels, the openings 104 are provided at positions displaced from each other.

  In the example shown in the drawing, six types of opening masks 103 that are shifted in the left-right direction are prepared as the positions of the openings 104 for the respective pixels. The entire image sensor 100 has a two-dimensional and periodic array of photoelectric conversion element groups each including a set of six parallax pixels each having an aperture mask 103 that gradually shifts from the left side to the right side of the drawing. . That is, it can be said that the image sensor 100 is configured by periodically repeating a repeating pattern 110 including a set of photoelectric conversion element groups.

  FIG. 4 is a conceptual diagram illustrating the relationship between the parallax pixels and the subject. In particular, FIG. 4A shows a photoelectric conversion element group of a repetitive pattern 110t arranged in the center orthogonal to the photographing optical axis 21 in the image pickup element 100, and FIG. 4B shows a repetitive arrangement arranged in the peripheral portion. The photoelectric conversion element group of the pattern 110u is typically shown. The subject 30 in FIGS. 4A and 4B is in the in-focus position with respect to the photographic lens 20. FIG. 4C schematically shows a relationship when the subject 31 existing at the out-of-focus position with respect to the photographing lens 20 is captured corresponding to FIG.

  First, the relationship between the parallax pixels and the subject when the photographing lens 20 captures the subject 30 that is in focus will be described. The subject luminous flux passes through the pupil of the photographic lens 20 and is guided to the image sensor 100. Six partial areas Pa to Pf are defined for the entire cross-sectional area through which the subject luminous flux passes. For example, in the pixel at the left end of the sheet of the photoelectric conversion element group constituting the repetitive patterns 110t and 110u, only the subject luminous flux emitted from the partial region Pf reaches the photoelectric conversion element 108 as can be seen from the enlarged view. The position of the opening 104f of the opening mask 103 is determined. Similarly, toward the rightmost pixel, the position of the opening 104e corresponding to the partial area Pe, the position of the opening 104d corresponding to the partial area Pd, and the position of the opening 104c corresponding to the partial area Pc. However, the position of the opening 104b is determined corresponding to the partial area Pb, and the position of the opening 104a is determined corresponding to the partial area Pa.

  In other words, the position of the opening 104f is determined by the inclination of the principal ray Rf of the subject light beam (partial light beam) emitted from the partial region Pf, which is defined by the relative positional relationship between the partial region Pf and the leftmost pixel, for example. It may be said that it is established. Then, when the photoelectric conversion element 108 receives the subject luminous flux from the subject 30 existing at the in-focus position via the opening 104f, the subject luminous flux is coupled on the photoelectric conversion element 108 as shown by the dotted line. Image. Similarly, toward the rightmost pixel, the position of the opening 104e is determined by the inclination of the principal ray Re, the position of the opening 104d is determined by the inclination of the principal ray Rd, and the position of the opening 104c is determined by the inclination of the principal ray Rc. It can be said that the position of the opening 104b is determined by the inclination of the light ray Rb, and the position of the opening 104a is determined by the inclination of the principal ray Ra.

  As shown in FIG. 4A, the light beam emitted from the minute region Ot on the subject 30 that intersects the optical axis 21 among the subject 30 existing at the in-focus position passes through the pupil of the photographing lens 20. Then, each pixel of the photoelectric conversion element group constituting the repetitive pattern 110t is reached. That is, each pixel of the photoelectric conversion element group constituting the repetitive pattern 110t receives a light beam emitted from one minute region Ot through each of the six partial regions Pa to Pf. Although the minute region Ot has an extent corresponding to the positional deviation of each pixel of the photoelectric conversion element group constituting the repetitive pattern 110t, it can be approximated to substantially the same object point. Similarly, as shown in FIG. 4B, the light beam emitted from the minute region Ou on the subject 30 that is separated from the optical axis 21 among the subject 30 that exists at the in-focus position passes through the pupil of the photographing lens 20. It passes through and reaches each pixel of the photoelectric conversion element group constituting the repetitive pattern 110u. That is, each pixel of the photoelectric conversion element group constituting the repetitive pattern 110u receives a light beam emitted from one minute region Ou through each of the six partial regions Pa to Pf. Similarly to the micro area Ot, the micro area Ou has an extent corresponding to the positional deviation of each pixel of the photoelectric conversion element group constituting the repetitive pattern 110u, but substantially the same object point. Can be approximated.

  In other words, as long as the subject 30 exists at the in-focus position, the minute area captured by the photoelectric conversion element group differs according to the position of the repetitive pattern 110 on the image sensor 100, and each pixel constituting the photoelectric conversion element group Captures the same minute region through different partial regions. In each repetitive pattern 110, corresponding pixels receive the subject luminous flux from the same partial area. That is, in the figure, for example, the leftmost pixel of each of the repeated patterns 110t and 110u receives the subject light flux from the same partial region Pf.

  In the repetitive pattern 110t arranged in the center orthogonal to the photographing optical axis 21, the left end pixel in the repetitive pattern 110u arranged in the peripheral portion and the position of the opening 104f where the left end pixel receives the subject light beam from the partial region Pf. However, the position of the opening 104f that receives the subject luminous flux from the partial region Pf is strictly different. However, from a functional point of view, these can be treated as the same type of aperture mask in terms of an aperture mask for receiving the subject light flux from the partial region Pf. Therefore, in the example of FIG. 4, it can be said that each of the parallax pixels arranged on the image sensor 100 includes one of six types of aperture masks.

  Next, the relationship between the parallax pixels and the subject when the photographing lens 20 captures the subject 31 existing in the out-of-focus state will be described. Also in this case, the subject luminous flux from the subject 31 present at the out-of-focus position passes through the six partial areas Pa to Pf of the pupil of the photographing lens 20 and reaches the image sensor 100. However, the subject light flux from the subject 31 existing at the out-of-focus position forms an image at another position, not on the photoelectric conversion element 108. For example, as illustrated in FIG. 4C, when the subject 31 exists at a position farther from the imaging element 100 than the subject 30, the subject light flux forms an image on the subject 31 side with respect to the photoelectric conversion element 108. Conversely, when the subject 31 is present at a position closer to the image sensor 100 than the subject 30, the subject luminous flux forms an image on the opposite side of the subject 31 from the photoelectric conversion element 108.

Therefore, the subject luminous flux emitted from the minute region Ot ′ among the subjects 31 existing at the out-of-focus position depends on which of the six partial regions Pa to Pf, the corresponding pixels in the different sets of repetitive patterns 110. To reach. For example, as shown in the enlarged view of FIG. 4C, the subject luminous flux that has passed through the partial region Pd is incident on the photoelectric conversion element 108 having the opening 104d included in the repeated pattern 110t ′ as the principal ray Rd ′. To do. Even if the subject light beam is emitted from the minute region Ot ′, the subject light beam that has passed through another partial region does not enter the photoelectric conversion element 108 included in the repetitive pattern 110t ′, and the repetitive pattern in the other repetitive pattern. The light enters the photoelectric conversion element 108 having a corresponding opening. In other words, the subject luminous flux reaching each photoelectric conversion element 108 constituting the repetitive pattern 110t ′ is a subject luminous flux radiated from different minute areas of the subject 31. That is, a subject luminous flux having a principal ray as Rd ′ is incident on 108 corresponding to the opening 104d, and the principal rays are incident on Ra ⁺ , Rb ⁺ , Rc ⁺ , Re to the photoelectric conversion elements 108 corresponding to the other openings. ^+, although subject light flux to Rf ⁺ is incident, these object light is a subject light flux emitted from different micro region of the object 31. Such a relationship is the same in the repeated pattern 110u arranged in the peripheral portion in FIG.

  Then, when viewed as a whole of the imaging element 100, for example, the subject image A captured by the photoelectric conversion element 108 corresponding to the opening 104a and the subject image D captured by the photoelectric conversion element 108 corresponding to the opening 104d are: If the image is for the subject present at the in-focus position, there is no shift, and if the image is for the subject present at the out-of-focus position, there is a shift. Then, the direction and amount of the shift are determined by how much the subject existing at the out-of-focus position is shifted from the focus position and by the distance between the partial area Pa and the partial area Pd. That is, the subject image A and the subject image D are parallax images. Since this relationship is the same for the other openings, six parallax images are formed corresponding to the openings 104a to 104f.

  Therefore, when the outputs of the pixels corresponding to each other in each of the repetitive patterns 110 configured in this way are collected, a parallax image is obtained. That is, the output of the pixel that has received the subject light beam emitted from a specific partial area among the six partial areas Pa to Pf forms a parallax image.

  FIG. 5 is a conceptual diagram illustrating processing for generating a parallax image. The figure shows, in order from the left column, the generation of the parallax image data Im_f generated by collecting the outputs of the parallax pixels corresponding to the opening 104f, the generation of the parallax image data Im_e by the output of the opening 104e, the opening State of generation of parallax image data Im_d by output of 104d, state of generation of parallax image data Im_c by output of opening 104c, state of generation of parallax image data Im_b by output of opening 104b, parallax by output of opening 104a This represents how the image data Im_a is generated. First, how the parallax image data Im_f is generated by the output of the opening 104f will be described.

  A repeating pattern 110 composed of a group of photoelectric conversion elements each including six parallax pixels is arranged in a horizontal row. Therefore, the parallax pixels having the opening 104f are present every six pixels in the left-right direction and continuously in the vertical direction on the virtual imaging element 100 excluding the pixels without parallax. Each of these pixels receives the subject luminous flux from different microregions as described above. Therefore, when the outputs of these parallax pixels are collected and arranged, a parallax image is obtained.

  However, since each pixel of the image sensor 100 according to the present embodiment is a square pixel, simply gathering results in the result that the number of pixels in the horizontal direction is reduced to 1/6, and vertically long image data is generated. End up. Therefore, by performing an interpolation process to obtain the number of pixels 6 times in the horizontal direction, the parallax image data Im_f is generated as an image with an original aspect ratio. However, since the parallax image data before the interpolation processing is an image that is thinned by 1/6 in the horizontal direction, the resolution in the horizontal direction is lower than the resolution in the vertical direction. That is, it can be said that the number of generated parallax image data and the improvement in resolution are in a conflicting relationship. A specific interpolation process applied to this embodiment will be described later.

  Similarly, parallax image data Im_e to parallax image data Im_a are obtained. That is, the digital camera 10 can generate a six-view parallax image having parallax in the horizontal direction.

  Next, the color filter 102 and the parallax image will be described. FIG. 6 is a diagram for explaining the Bayer arrangement. As shown in the figure, the Bayer array is an array in which the green filter is assigned to the upper left and lower right pixels, the red filter is assigned to the lower left pixel, and the blue filter is assigned to the upper right pixel. Here, the upper left pixel to which the green filter is assigned is the Gb pixel, and the lower right pixel to which the green filter is assigned is the Gr pixel. In addition, a pixel to which a red filter is assigned is an R pixel, and a pixel to which blue is assigned is a B pixel. A horizontal direction in which Gb pixels and B pixels are arranged is defined as Gb row, and a horizontal direction in which R pixels and Gr pixels are arranged is defined as Gr row. A vertical direction in which Gb pixels and R pixels are arranged is a Gb column, and a vertical direction in which B pixels and Gr pixels are arranged is a Gr column.

  With respect to such an arrangement of the color filters 102, an enormous number of repetitive patterns 110 can be set depending on what color pixels the parallax pixels and non-parallax pixels are allocated to. If the outputs of pixels without parallax are collected, photographic image data having no parallax can be generated in the same way as normal photographic images. Therefore, if the ratio of pixels without parallax is relatively increased, a 2D image with high resolution can be output. In this case, since the number of parallax pixels is relatively small, the image quality is degraded as a 3D image including a plurality of parallax images. Conversely, if the ratio of the parallax pixels is increased, the image quality is improved as a 3D image, but the non-parallax pixels are relatively reduced, so that a 2D image with low resolution is output.

  In such a trade-off relationship, a repetitive pattern 110 having various characteristics is set depending on which pixel is a parallax pixel or a non-parallax pixel. FIG. 7 is a diagram illustrating a variation in the case where there are two types of parallax pixels with respect to the allocation of parallax pixels to the Bayer array. The parallax pixels in this case are assumed to be a parallax Lt pixel in which the opening 104 is decentered to the left of the center and a parallax Rt pixel that is also decentered to the right. That is, the two viewpoint parallax images output from such parallax pixels realize so-called stereoscopic vision.

  The description of the features for each repetitive pattern is as shown in the figure. For example, if many non-parallax pixels are allocated, high-resolution 2D image data is obtained, and if all pixels of RGB are equally allocated, high-quality 2D image data with little color shift is obtained. On the other hand, if a large number of parallax pixels are allocated, high-resolution 3D image data is obtained, and if all the RGB pixels are allocated equally, a high-quality image with good color reproducibility can be obtained while being a 3D image. Color image data.

  Some variations are described below. FIG. 8 is a diagram illustrating an example of a variation. The variation in FIG. 8 corresponds to the repeated pattern classification A-1 in FIG.

  In the example of the figure, the same four pixels as the Bayer array are used as the repeated pattern 110. The R pixel and the B pixel are non-parallax pixels, and the Gb pixel is assigned to the parallax Lt pixel and the Gr pixel is assigned to the parallax Rt pixel. In this case, the opening 104 is defined so that the parallax Lt pixel and the parallax Rt pixel included in the same repetitive pattern 110 receive the light beam emitted from the same minute region when the subject is in the in-focus position. .

  In the example of the figure, Gb pixels and Gr pixels, which are green pixels with high visibility, are used as parallax pixels, so that it is expected to obtain a parallax image with high contrast. In addition, since the Gb pixel and the Gr pixel which are the same green pixels are used as the parallax pixels, it is easy to perform a conversion operation from these two outputs to an output having no parallax, and the output of the R pixel and the B pixel which are non-parallax pixels is high. High-quality 2D image data can be generated. The conversion operation will be described later.

  FIG. 9 is a diagram illustrating an example of another variation. The variations in FIG. 9 correspond to the repeated pattern classification B-1 in FIG.

  In the example shown in the figure, the repeated pattern 110 is 8 pixels in which 4 pixels in the Bayer array are two sets on the left and right. Among the eight pixels, the parallax Lt pixel is assigned to the left Gb pixel, and the parallax Rt pixel is assigned to the right Gb pixel. In such an arrangement, the Gr pixel is a non-parallax pixel, so that higher image quality of the 2D image can be expected than in the example of FIG.

  FIG. 10 is a diagram illustrating an example of still another variation. The variation in FIG. 10 corresponds to the repeated pattern classification D-1 in FIG.

  In the example shown in the figure, the repeated pattern 110 is 8 pixels in which 4 pixels in the Bayer array are two sets on the left and right. Among the eight pixels, the parallax Lt pixel is assigned to the left Gb pixel, and the parallax Rt pixel is assigned to the right Gb pixel. Further, the parallax Lt pixel is assigned to the left R pixel, and the parallax Rt pixel is assigned to the right R pixel. Further, the parallax Lt pixel is assigned to the left B pixel, and the parallax Rt pixel is assigned to the right B pixel. Non-parallax pixels are assigned to the two Gr pixels.

  The parallax Lt pixel and the parallax Rt pixel assigned to the two Gb pixels receive the light flux emitted from one minute region when the subject is in the in-focus position. In addition, the parallax Lt pixel and the parallax Rt pixel assigned to the two R pixels receive a light beam emitted from one minute region different from that of the Gb pixel, and the parallax Lt pixel assigned to the two B pixels The parallax Rt pixel receives a light beam emitted from one minute region different from that of the Gb pixel and the R pixel. Therefore, compared with the example of FIG. 9, the resolution as a 3D image is tripled in the vertical direction. Moreover, since RGB three-color output can be obtained, it is a high-quality 3D image as a color image.

  As described above, if two types of parallax pixels are used, a parallax image with two viewpoints can be obtained. Of course, various types of parallax pixels can be used according to the number of parallax images to be output. Even if the number of viewpoints is increased, various repeated patterns 110 can be formed. Therefore, it is possible to select the repetitive pattern 110 according to the specification, purpose, and the like.

  In the above-described example, the case where the Bayer array is adopted as the color filter array has been described. Of course, other color filter arrays may be used. At this time, each of the parallax pixels constituting the set of photoelectric conversion element groups may include an opening mask 103 having opening portions 104 facing different partial regions.

  Therefore, the image sensor 100 is provided in a one-to-one correspondence with each of at least a part of the photoelectric conversion elements 108 and the photoelectric conversion elements 108 that are two-dimensionally arranged to photoelectrically convert incident light into electric signals. The aperture mask 103 and the color filters 102 provided in a one-to-one correspondence with each of at least a part of the photoelectric conversion elements 108 are provided, and n adjacent n (n is an integer of 3 or more) photoelectric conversion elements 108. Of these, the openings 104 of the respective opening masks 103 provided corresponding to at least two (may be three or more) are composed of at least three types of color filters 102 that transmit different wavelength bands. The color filter pattern is included in one pattern and the light beams from different partial areas in the cross-sectional area of the incident light pass through each. So as positioned, the photoelectric conversion element group for the n-number of photoelectric conversion elements 108 and a set is only to be periodically arranged.

  FIG. 11 is a diagram for explaining another color filter arrangement. As shown in the figure, the other color filter array maintains the Gr pixels in the Bayer array shown in FIG. 6 as G pixels to which the green filter is assigned, while changing the Gb pixels to W pixels to which no color filter is assigned. It is. Note that, as described above, the W pixel may be arranged with a transparent filter that is not colored so as to transmit substantially all the wavelength band of visible light.

  If such a color filter array including W pixels is adopted, the accuracy of the color information output from the image sensor is slightly reduced, but the amount of light received by the W pixels is larger than that when a color filter is provided. Therefore, highly accurate luminance information can be acquired. A monochrome image can also be formed by gathering the outputs of W pixels.

  In the case of a color filter array including W pixels, there are further variations in the repeating pattern 110 of parallax pixels and non-parallax pixels. For example, even if the image is captured in a relatively dark environment, the contrast of the subject image is higher if the image is output from the W pixel as compared to the image output from the color pixel. Therefore, if a parallax pixel is assigned to a W pixel, a highly accurate calculation result can be expected in a matching process performed between a plurality of parallax images. Therefore, in addition to the influence on the resolution of the 2D image and the image quality of the parallax image, the repetitive pattern 110 of the parallax pixels and the non-parallax pixels is set in consideration of the interest in other extracted information.

  FIG. 12 is a diagram illustrating an example of an array of W pixels and parallax pixels when the other color filter array of FIG. 11 is employed. The variation in FIG. 12 is similar to the repeated pattern classification B-1 in FIG. In the example shown in the figure, the repeated pattern 110 is an eight pixel in which two sets of four pixels in other color filter arrays continue to the left and right. Among the eight pixels, the parallax Lt pixel is assigned to the left W pixel, and the parallax Rt pixel is assigned to the right W pixel. In such an arrangement, the image sensor 100 can output a parallax image as a monochrome image and output a 2D image as a color image.

  In this case, the image sensor 100 is provided in a one-to-one correspondence with each of the two-dimensionally arranged photoelectric conversion elements 108 that photoelectrically convert incident light into electric signals and at least a part of the photoelectric conversion elements 108. And n adjacent n (n is an integer of 4 or more) photoelectric conversion elements each having an opening mask 103 and a color filter 102 provided in a one-to-one correspondence with each of at least a part of the photoelectric conversion element 108. The openings 104 of the respective opening masks 103 provided corresponding to at least two out of 108 are in one pattern of a color filter pattern composed of at least three kinds of color filters 102 that transmit different wavelength bands. And is positioned so as to pass light beams from different partial areas in the cross-sectional area of the incident light, The photoelectric conversion element group for a number of photoelectric conversion elements 108 and a set is only to be periodically arranged.

  As described above, the pixels constituting the image sensor 100 are parallax pixels and non-parallax pixels when focusing on the opening 104, and R, G, B, and W pixels when focusing on the color filter 102. Are characterized in various combinations. Therefore, even if the outputs of the image sensor 100 are aligned with the pixel arrangement, they are not image data representing a specific image. That is, only when the pixel outputs of the image sensor 100 are separated and collected for each pixel group characterized by the same, image data representing one image corresponding to the feature is formed. For example, as already described with reference to FIG. 5, when the outputs of the parallax pixels are collected for each type of opening, a plurality of parallax image data having parallax can be obtained. In this way, each piece of image data separated and collected for each identically characterized pixel group is referred to as plane data.

The image processing unit 205 receives raw raw image data whose output values are arranged in the pixel arrangement order of the image sensor 100, and executes plane separation processing for separating the raw image data into a plurality of plane data. FIG. 13 is a diagram for explaining the plane separation process using the B′-1 repetition pattern described with reference to FIG. 12 as an example. As shown in the figure, with respect to the pixel array of the image sensor 100, the i axis is determined rightward and the j axis is determined downward. Also, the left end and upper end coordinates are (1, 1), and the right end and lower end coordinates are (i ₀ , j ₀ ). In the figure, description is made so that the types of pixels can be understood in accordance with the example of FIG. 12, but output values corresponding to the respective pixels are arranged as actual plane data.

As schematically illustrated in the upper part of FIG. 13, the RAW original image data has a parallax Lt pixel, a B pixel without parallax, from (1, 1) to (i ₀ , 1) in the i = 1st row. The respective output values are repeatedly arranged in the order of the parallax Rt pixel and the non-parallax B pixel. In the i = 2nd row, the output values are repeatedly arranged in the order of R pixels without parallax and G pixels without parallax (Gr pixels) from (1,2) to (i ₀ , 2). In the RAW original image data, such output values in the row direction are alternately and repeatedly arranged in the column direction.

The image processing unit 205 sets the RAW source image data to the respective planes using the parallax Lt pixel, the parallax Rt pixel, the non-parallax R pixel, the non-parallax G pixel, and the non-parallax B pixel as the same pixel group. Separate into data. In the repeating pattern of B′−1, the RGB color pixels are non-parallax pixels, and the parallax pixels are W pixels. Therefore, the image processing unit 205 generates R ₀ plane data by separating only R pixels without parallax from the RAW original image data, generates G ₀ plane data by separating only G pixels without parallax, and has no parallax. and generates B ₀ plane data only by separating B pixel, it managed as color image data are collectively.

Similarly, the image processing unit 205 separates only the parallax Lt pixels from the RAW original image data to generate Lt ₀ plane data, and separates only the parallax Rt pixels to generate Rt ₀ plane data. Collectively manage parallax image data. Here, it can be said that the parallax image data does not include color information and represents luminance information of the subject image, and thus can be handled as luminance image data. Therefore, in the present embodiment, the output value of each plane belonging to color image data is referred to as a pixel value, and the output value of each plane belonging to luminance image data is referred to as a luminance value. Further, the image processing unit 205 manages color image data and parallax image data as a RAW image data set as a plane data group generated from one RAW original image data.

As shown in the drawing, each plane data at this point has an output value only at a pixel position where the output value exists in the RAW original image data. For example, in the _R0 plane data, output values (pixel values) exist for two pixels for one repetitive pattern 110, and the remaining six pixels exist as empty grids. Similarly, in the Lt ₀ plane data, the output value (luminance value) for one repetitive pattern exists for one pixel, and the other seven pixels exist as an empty grid. Therefore, the image processing unit 205 executes an interpolation process for filling the empty grid of each plane data.

FIG. 14 is a diagram for explaining the plane data interpolation processing. Here, a state is shown in which interpolation processing is performed on _R0 plane data in which vacancies exist to generate Rn plane data in which vacancies do not exist.

  As an interpolation process, the image processing unit 205 uses the pixel values of the pixels close to the empty grid to generate the pixel values of the empty grid. For example, if there is a pixel value in a pixel adjacent to the target empty grid, the average value thereof is set as the pixel value of the empty grid. When non-adjacent pixels are used, averaging processing is performed by giving a weight according to the distance from the empty lattice.

  When interpolation processing is performed in this way, empty grids can be eliminated from each plane data. FIG. 15 is a diagram for explaining the data structure of the RAW image data set after performing the interpolation process.

  As shown in the figure, the color image data constituting the RAW image data set includes Rn plane data, Gn plane data, and Bn plane data having no empty lattice. These image data correspond to image data obtained by extracting only the red component, image data obtained by extracting only the green component, and image data obtained by extracting only the blue component, respectively.

  Similarly, the parallax image data (luminance image data) constituting the RAW image data set includes Lt plane data and Rt plane data having no empty lattice. Each of these image data corresponds to image data obtained by extracting only the luminance component of the left viewpoint from the subject image, and image data obtained by extracting only the luminance component of the right viewpoint.

  In the present embodiment, the image processing unit 205 uses these five plane data to generate left-viewpoint color image data and right-viewpoint color image data. In particular, by introducing a three-dimensional adjustment parameter, color image data in which the parallax amount is arbitrarily adjusted while maintaining the blur amount is generated. Prior to specific processing, the generation principle will be described first.

  FIG. 16 is a diagram for explaining the concept of defocusing. As shown in FIG. 16A, when an object point that is a subject exists at the focal position, the subject luminous flux that reaches the image sensor light receiving surface through the lens pupil is steep with the pixel at the corresponding image point as the center. The light intensity distribution is shown. That is, if non-parallax pixels that receive the entire effective luminous flux that passes through the lens pupil are arranged in the vicinity of the image point, the output value of the pixel corresponding to the image point is the largest, and the output value of the pixels arranged in the vicinity Drops rapidly.

  On the other hand, as shown in FIG. 16B, when the object point deviates from the focal position, the subject luminous flux shows a gentle light intensity distribution on the light receiving surface of the image sensor as compared with the case where the object point exists at the focal position. . That is, the output value at the pixel of the corresponding image point is lowered, and a distribution having output values up to the peripheral pixels is shown.

  Further, as shown in FIG. 16C, when the object point further deviates from the focal position, the subject luminous flux exhibits a gentler light intensity distribution on the image sensor light receiving surface. In other words, the output value at the pixel of the corresponding image point further decreases, and a distribution having output values up to the surrounding pixels is shown.

  Next, the concept of defocusing when the parallax Lt pixel and the parallax Rt pixel receive light will be described. FIG. 17 is a diagram for explaining the concept of parallax pixel defocusing. The parallax Lt pixel and the parallax Rt pixel receive the subject luminous flux that arrives from one of the two parallax virtual pupils set as the optical axis target as a partial region of the lens pupil.

  As shown in FIG. 17 (a), when an object point that is a subject exists at the focal position, steep light centering on the pixel of the corresponding image point regardless of the parallax virtual pupil, regardless of the parallax virtual pupil. The intensity distribution is shown. If the parallax Lt pixels are arranged in the vicinity of the image point, the output value of the pixel corresponding to the image point is the largest, and the output value of the pixels arranged in the vicinity rapidly decreases. Further, even when the parallax Rt pixels are arranged in the vicinity of the image point, the output value of the pixel corresponding to the image point is the largest, and the output value of the pixels arranged in the vicinity rapidly decreases. That is, even if the subject luminous flux passes through any parallax virtual pupil, the output value of the pixel corresponding to the image point is the largest, and the output value of the pixels arranged in the vicinity rapidly decreases. Match each other.

  On the other hand, as shown in FIG. 17B, when the object point deviates from the focal position, the peak of the light intensity distribution indicated by the parallax Lt pixel corresponds to the image point as compared with the case where the object point exists at the focal position. Appearing at a position away from the pixel in one direction, and its output value decreases. In addition, the width of the pixel having the output value is increased. The peak of the light intensity distribution indicated by the parallax Rt pixel appears at a position away from the pixel corresponding to the image point in the opposite direction to the one direction in the parallax Lt pixel and at an equal distance, and the output value similarly decreases. Similarly, the width of the pixel having the output value is increased. That is, the same light intensity distribution that is gentler than that in the case where the object point exists at the focal position appears at an equal distance from each other. Further, as shown in FIG. 17C, when the object point further deviates from the focal position, the same light intensity distribution that is more gentle than the state of FIG. . That is, it can be said that the amount of blur and the amount of parallax increase as the object point deviates from the focal position. In other words, the amount of blur and the amount of parallax change in conjunction with defocus. That is, the amount of blur and the amount of parallax have a one-to-one relationship.

  When the change in the light intensity distribution described with reference to FIG. 16 and the change in the light intensity distribution described with reference to FIG. 17 are graphed, they are expressed as shown in FIG. In the figure, the horizontal axis represents the pixel position, and the center position is the pixel position corresponding to the image point. The vertical axis represents the output value of each pixel. Since this output value is substantially proportional to the light intensity, it is shown as the light intensity in the figure.

  FIG. 18A is a graph showing changes in the light intensity distribution described in FIG. A distribution curve 1801 represents the light intensity distribution corresponding to FIG. 16A and shows the steepest state. The distribution curve 1802 represents the light intensity distribution corresponding to FIG. 16B, and the distribution curve 1803 represents the light intensity distribution corresponding to FIG. Compared with the distribution curve 1801, it can be seen that the peak value gradually decreases and has a broadening.

  FIG. 18B is a graph showing changes in the light intensity distribution described in FIG. A distribution curve 1804 and a distribution curve 1805 represent the light intensity distribution of the parallax Lt pixel and the light intensity distribution of the parallax Rt pixel in FIG. As can be seen from the figure, these distributions have a line-symmetric shape with respect to the center position. Further, a combined distribution curve 1806 obtained by adding these together shows a similar shape to the distribution curve 1802 in FIG. 16B, which is in a defocus state equivalent to that in FIG.

  A distribution curve 1807 and a distribution curve 1808 respectively represent the light intensity distribution of the parallax Lt pixel and the light intensity distribution of the parallax Rt pixel in FIG. As can be seen from the figure, these distributions are also symmetrical with respect to the center position. Also, a combined distribution curve 1809 obtained by adding them shows a similar shape to the distribution curve 1803 in FIG. 16C, which is in a defocus state equivalent to that in FIG.

  In the present embodiment, the luminance value of the parallax Lt pixel and the luminance value of the parallax Rt pixel, which are actually obtained as the output value of the image sensor 100 and interpolated in the sky lattice and indicate such a light intensity distribution, are used. To create a virtual light intensity distribution. At this time, the amount of parallax expressed as an interval between peaks is adjusted while approximately maintaining the amount of blur expressed by the spread of the light intensity distribution. That is, in this embodiment, the image processing unit 205 maintains the amount of blurring as an image as it is, but adjusts the parallax adjusted between the 2D image generated from the non-parallax pixel and the 3D image generated from the parallax pixel. An image having a quantity is generated. FIG. 19 is a diagram showing a light intensity distribution for explaining the concept of the adjusted parallax amount.

  Lt distribution curves 1901 and Rt distribution curves 1902 indicated by solid lines in the figure are distribution curves in which actual luminance values of Lt plane data and Rt plane data are plotted. For example, it corresponds to the distribution curves 1804 and 1805 in FIG. The distance between the peaks of the Lt distribution curve 1901 and the Rt distribution curve 1902 represents the 3D parallax amount, and the greater the distance, the stronger the stereoscopic effect during image reproduction.

  A 2D distribution curve 1903 obtained by adding 50% each of the Lt distribution curve 1901 and the Rt distribution curve 1902 has a convex shape with no left-right bias. The 2D distribution curve 1903 corresponds to a shape in which the height of the composite distribution curve 1806 in FIG. 18 is halved. That is, the 2D distribution curve 1903 shows a shape similar to a distribution curve in which the luminance values of pixels without parallax are plotted. That is, an image based on this luminance distribution is a 2D image with a parallax amount of zero.

  The adjusted Lt distribution curve 1905 is a curve obtained by adding 80% of the Lt distribution curve 1901 and 20% of the Rt distribution curve 1902. The peak of the adjusted Lt distribution curve 1905 is displaced closer to the center than the peak of the Lt distribution curve 1901 as much as the component of the Rt distribution curve 1902 is added. Similarly, the adjusted Rt distribution curve 1906 is a curve obtained by adding 20% of the Lt distribution curve 1901 and 80% of the Rt distribution curve 1902. The peak of the adjusted Rt distribution curve 1906 is displaced closer to the center than the peak of the Rt distribution curve 1902 by the amount to which the component of the Lt distribution curve 1901 is added.

  Therefore, the adjusted parallax amount represented by the distance between the peaks of the adjusted Lt distribution curve 1905 and the adjusted Rt distribution curve 1906 is smaller than the 3D parallax amount. Therefore, the stereoscopic effect during image reproduction is alleviated. On the other hand, since the spread of each of the adjusted Lt distribution curve 1905 and the adjusted Rt distribution curve 1906 is equivalent to the spread of the 2D distribution curve 1903, it can be said that the amount of blur is equal to that of the 2D image.

  That is, the amount of adjustment parallax can be controlled depending on the ratio of the Lt distribution curve 1901 and the Rt distribution curve 1902 to be added. Then, by applying this adjusted luminance distribution to each plane of the color image data generated from the non-parallax pixels, the color image of the left viewpoint that gives a stereoscopic effect different from that of the parallax image data generated from the parallax pixels Data and right-view color image data can be generated.

In the present embodiment, color image data for the left viewpoint and color image data for the right viewpoint are generated from the five plane data constituting the RAW image data set. Color image data of the left viewpoint, RLt _c plane data is red plane data corresponding to the left viewpoint, a green plane data GLt _c plane data, and three color parallax plane data BLt _c plane data is blue plane data Consists of. Similarly, the color image data of the right-side perspective is, RRT _c plane data is red plane data corresponding to the right viewpoint, a green plane data GRT _c plane data, and three of BRt _c plane data is blue plane Datacolor Consists of parallax plane data.

FIG. 20 is a diagram for explaining color parallax plane data generation processing. In particular, a generation process of RLt _c plane data and RRt _c plane data, which are red parallax planes among color parallax planes, will be described.

The red parallax plane is generated using the pixel value of the Rn plane data described with reference to FIG. 15 and the luminance value of the Lt plane data and the Rt plane data. Specifically, for example, when calculating the pixel value RLt _mn of the target pixel position (i _m , j _n ) of the RLt _c plane data, first, the pixel value extraction unit 231 of the image processing unit 205 is identical to the Rn plane data. A pixel value Rn _mn is extracted from the pixel position (i _m , j _n ). Next, the luminance value extracting unit 232 of the image processing section 205, the same pixel position of Lt plane data _(i m, _{j n)} the luminance value _{Lt mn} from the same pixel position of Rt plane data _{(i m, j} n) The luminance value Rt _mn is extracted from. The calculation unit 233 of the image processing unit 205, the pixel values _{Rn mn,} by multiplying the value obtained by distributing the luminance value _{Lt mn} and _{Rt mn} stereoscopic adjustment parameter C, and calculates the pixel value _{RLt mn.} Specifically, it is calculated by the following equation (1). However, the three-dimensional adjustment parameter C is preset in the range of 0.5 <C <1.
RLt _mn = 2Rn _mn × {C · Lt _mn + (1-C) · Rt _mn } / (Lt _mn + Rt _mn ) (1)

Similarly, also when calculating the pixel value RRt _mn of the target pixel position (i _m , j _n ) of the RRt _c plane data, the calculation unit 233 adds the luminance value to the pixel value Rn _mn extracted by the pixel value extraction unit 231. The luminance value Lt _mn extracted by the extraction unit 232 and the luminance value Rt _mn are calculated by multiplying the values distributed by the three-dimensional adjustment parameter C. Specifically, it is calculated by the following equation (2).
RRt _mn = 2Rn _mn × {C · Rt _mn + (1-C) · Lt _mn } / (Lt _mn + Rt _mn ) (2)

The image processing unit 205 sequentially executes such processing from (1, 1) which is the pixel at the left end and the upper end to (i ₀ , j ₀ ) which is the coordinates at the right end and the lower end.

When the generation processing of RLt _c plane data and RRt _c plane data that are red parallax planes is completed, generation processing of GLt _c plane data and GRt _c plane data that are green parallax planes is then executed. Specifically, the pixel same pixel position _(i m, _{j n)} of Rn plane data in the above description, instead of extracting the pixel values _{Rn mn} from the same pixel position of Gn plane data _(i m, _{j n)} from The value Gn _mn is extracted and processed in the same way. Further, when the generation processing of the GLt _c plane data and the GRt _c plane data which are green parallax planes is completed, the generation processing of the BLt _c plane data and BRt _c plane data which are blue parallax planes is executed next. Specifically, the pixel same pixel position _(i m, _{j n)} of Rn plane data in the above description, instead of extracting the pixel values _{Rn mn} from the same pixel position of Bn plane data _(i m, _{j n)} from The value Bn _mn is extracted and processed in the same way.

Through the above processing, left-view color image data (RLt _c- plane data, GLt _c- plane data, BLt _c- plane data) and right-view color image data (RRt _c- plane data, GRt _c- plane data, BRt _c- plane data) Is generated. That is, the color image data of the left viewpoint and the right viewpoint can be acquired by a relatively simple process as a virtual output that does not actually exist as a pixel of the image sensor 100.

  In addition, since the stereoscopic adjustment parameter C can be changed in the range of 0.5 <C <1, the amount of parallax can be adjusted while maintaining the amount of blur of the 2D color image due to the pixels without parallax. Therefore, if these image data are played back by a playback device that supports 3D images, the user can view 3D video with a three-dimensional effect adjusted appropriately as a color image. In particular, since the processing is simple, it is possible to generate image data at high speed and to deal with moving images.

  In the above description, if parallax pixels are evenly allocated to all RGB pixels on the actual image sensor 100, high-quality color image data with good color reproducibility can be obtained while being a 3D image. However, it can be said that high-quality 3D color image data according to this can be obtained by performing the above processing even if such pixels are not actually provided. In addition, since it is not necessary to allocate parallax pixels to RGB pixels as actual pixels, the quality of other plane data can be improved accordingly.

  Next, the above processing will be described from the viewpoint of light intensity distribution and color. FIG. 21 is a diagram for explaining a change in RGB light intensity distribution. FIG. 21A shows the output value of the parallax Lt pixel and the output value of the parallax Rt pixel when the subject luminous flux from an object point located at a position deviated by a certain amount from the focal position is received. It is a graph. These output values are luminance values not including color information. Further, as described above, since the output value of the pixel is proportional to the light intensity, it can be said that the graph represents the light intensity distribution.

  FIG. 21B is a graph in which output values of R pixels, G pixels, and B pixels, which are non-parallax pixels, are arranged when the subject luminous flux from the object point in FIG. 21A is received. These output values are pixel values including color information. It can also be said that this graph also represents the light intensity distribution of each color.

  When the above process is performed for each corresponding pixel with C = 0.8, the light intensity distribution represented by the graph in FIG. As can be seen from the figure, a distribution corresponding to the pixel values of RGB is obtained.

  Next, the process until the generation of parallax color image data will be described from the viewpoint of the processing flow. FIG. 22 is a processing flow until generation of parallax color image data. The flow may be started in conjunction with the shooting operation, or may be started by reading target image data from the memory card 220.

In step S101, the image processing unit 205 acquires RAW original image data. Then, in step S102, as described with reference to FIG. 13, the RAW original image data, _{R 0} plane data as color image data, _{G 0} plane data, _{B 0} plane data, Lt ₀ plane as the parallax image data Data and Rt ₀ plane data are separated. In step S103, the image processing unit 205 executes an interpolation process for interpolating vacancies existing in the separated plane data. Specifically, as described with reference to FIG. 14, the output value of the empty grid is calculated by averaging processing using the output values of adjacent pixels.

  In step S104, the image processing unit 205 initializes each variable. Specifically, first, 1 is substituted into the color variable Cset. The color variable Cset represents 1 = red, 2 = green, 3 = blue. Also, 1 is substituted into the coordinate variables i and j. Further, 1 is substituted into the parallax variable S. The parallax variable S represents 1 = left, 2 = right.

In step S105, the pixel value extraction unit 231 of the image processing unit 205 extracts a pixel value from the target pixel position (i, j) of the Cset plane. For example, Cset = 1, when a target pixel position (1,1), pixel values to be extracted is _{Rn 11.} Further, the luminance value extraction unit 232 of the image processing unit 205 extracts a luminance value from the target pixel position (i, j) of the Lt plane data and the Rt plane data in step S106. For example, when the target pixel position is (1, 1), the luminance values to be extracted are Lt ₁₁ and Rt ₁₁ .

In step S107, the calculation unit 233 of the image processing unit 205 calculates the pixel value of the target pixel position (i, j) corresponding to the parallax variable S. For example, when Cset = 1 and S = 1 and the target pixel position is (1, 1), RLt ₁₁ is calculated. Specifically, for example, it is calculated by the above-described equation (1). Note that the three-dimensional adjustment parameter C is set in advance in a range of 0.5 <C <1. Specifically, for example, the control unit 201 receives and sets a user instruction through the operation unit 208.

  In step S108, the image processing unit 205 increments the parallax variable S. In step S109, it is determined whether or not the parallax variable S exceeds 2. If not, the process returns to step S107. If it exceeds, the process proceeds to step S110.

In step S110, the image processing unit 205 assigns 1 to the parallax variable S and increments the coordinate variable i. Then, in step S111, it is determined whether coordinate variable i exceeds _{i 0.} If not, the process returns to step S105. If it exceeds, the process proceeds to step S112.

In step S112, the image processing unit 205 assigns 1 to the coordinate variable i and increments the coordinate variable j. Then, in step S113, it is determined whether coordinate variable j exceeds _{j 0.} If not, the process returns to step S105. If it exceeds, the process proceeds to step S114.

When the process proceeds to step S114, since the pixel values of all the left and right pixels for Cset are aligned, the image processing unit 205 arranges these pixel values to generate plain image data. For example, when Cset = 1, RLt _c plane data and RRt _c plane data are generated.

In step S115, the image processing unit 205 assigns 1 to the coordinate variable j and increments the color variable Cset. In step S116, it is determined whether or not the color variable Cset exceeds 3. If not, the process returns to step S105. If it exceeds, color image data of the left viewpoint (RLt _c plane data, GLt _c plane data, BLt _c plane data) and color image data of the right viewpoint (RRt _c plane data, GRt _c plane data, BRt _c plane data) As a result, the series of processes is terminated.

  Next, a preferable opening shape of the opening 104 will be described. FIG. 23 is a diagram illustrating a preferred opening shape.

  It is preferable that the opening 104l of the parallax Lt pixel and the opening 104r of the parallax Rt pixel are offset in the opposite directions including the center with respect to the corresponding photoelectric conversion element 108. Specifically, each of the openings 104l and 104r has a shape in contact with a virtual center line 322 passing through the center (pixel center) of the photoelectric conversion element 108, or a shape straddling the center line 322. Is preferred.

  In particular, as illustrated, the shape of the opening 104l and the shape of the opening 104r are preferably the same as the respective shapes obtained by dividing the shape of the opening 104n of the non-parallax pixel by the center line 322. In other words, the shape of the opening 104n is preferably equal to the shape in which the shape of the opening 104l and the shape of the opening 104r are adjacent to each other.

  Next, a concept and process different from the concept and process described in FIGS. 19 to 21 will be described. FIG. 24 is a diagram illustrating a light intensity distribution for explaining another concept of the adjustment parallax amount.

  In FIG. 24A, an Lt distribution curve 1901 and an Rt distribution curve 1902 are distribution curves in which actual luminance values of Lt plane data and Rt plane data are plotted. Specifically, it is a curve in which luminance values are plotted in correspondence with pixel positions in the parallax direction, paying attention to a pixel array having a parallax direction. These curves correspond to, for example, the distribution curves 1804 and 1805 in FIG. The distance between the peaks of the Lt distribution curve 1901 and the Rt distribution curve 1902 represents the 3D parallax amount, and the greater the distance, the stronger the stereoscopic effect during image reproduction.

Two modulation curves are generated by plotting the values calculated by using the following two expressions at the respective pixel positions with respect to the Lt distribution curve 1901 and the Rt distribution curve 1902.
Lt modulation curve (1 / 2-C) (Lt-Rt)
Rt modulation curve (1 / 2-C) (Rt-Lt)
However, C is a three-dimensional adjustment parameter, and a real number of 0 <C <0.5 is usually adopted.

  FIG. 24B shows a state when the value of the three-dimensional adjustment parameter C is changed. The left figure shows the distribution when C = 0.2, and the Lt modulation curve 1913 and the Rt modulation curve 1914 are symmetrical with respect to the light intensity. Similarly, the middle figure shows the distribution when C = 0.3, and the right figure shows the case when C = 0.4.

  FIG. 24C shows a distribution curve 1915 in which pixel values of plane data of color image data to be subjected to stereo modulation are plotted. Specifically, it is a curve in which pixel values are plotted in correspondence with pixel positions in the parallax direction, focusing on a pixel array in the parallax direction. It can be said that this distribution curve also represents the light intensity distribution.

  FIG. 24D shows an adjusted Lt distribution curve 1916 and an adjusted Rt distribution curve 1917. Specifically, the adjusted Lt distribution curve 1916 is generated by adding the Lt modulation curve 1913 to the distribution curve 1915. The adjusted Rt distribution curve 1917 is generated by adding the Rt modulation curve 1914 to the distribution curve 1915. The left figure shows the distribution when C = 0.2, the middle figure shows C = 0.3, and the right figure shows C = 0.4. The distance between the peaks of the adjusted Lt distribution curve 1916 and the adjusted Rt distribution curve 1917 represents the adjusted parallax amount.

  For example, the change amount of the Lt modulation curve 1913 and the Rt modulation curve 1914 when C = 0.4 is smaller than that when C = 0.2. From this relationship, the adjusted parallax amount when C = 0.4 is smaller than that when C = 0.2. In addition, when the stereoscopic adjustment parameter C satisfies 0 <C <0.5, the adjustment parallax amount is smaller than the 3D parallax amount. Therefore, the stereoscopic effect during image reproduction is alleviated. On the other hand, since the spread of each of the adjusted Lt distribution curve 1916 and the adjusted Rt distribution curve 1917 is substantially equal to the spread of the distribution curve 1915, it can be said that the amount of blur is equal to that of the 2D image.

  That is, the amount of adjusted parallax can be controlled by how much the difference between the Lt distribution curve 1901 and the Rt distribution curve 1902 is correlated. By performing such calculation, it is possible to generate left-viewpoint color image data and right-viewpoint color image data that give a stereoscopic effect different from that of the parallax image data generated from the parallax pixels.

  In addition, by changing the value of the stereoscopic adjustment parameter C in the range of C <0, an adjustment parallax amount emphasized from the original 3D parallax amount is obtained, or by changing in the range of 0.5 <C, the parallax can be obtained. It is possible to realize reverse viewing in which the direction is reversed, and to apply various video effects.

In the present embodiment, color image data for the left viewpoint and color image data for the right viewpoint are generated from the five plane data constituting the RAW image data set. Color image data of the left viewpoint, RLt _c plane data is red plane data corresponding to the left viewpoint, a green plane data GLt _c plane data, and three color parallax plane data BLt _c plane data is blue plane data Consists of. Similarly, the color image data of the right-side perspective is, RRT _c plane data is red plane data corresponding to the right viewpoint, a green plane data GRT _c plane data, and three of BRt _c plane data is blue plane Datacolor Consists of parallax plane data.

FIG. 25 is a diagram for explaining color parallax plane data generation processing. In particular, a generation process of RLt _c plane data and RRt _c plane data, which are red parallax planes among color parallax planes, will be described.

The red parallax plane is generated using the pixel value of the Rn plane data described with reference to FIG. 15 and the luminance value of the Lt plane data and the Rt plane data. Specifically, for example, when calculating the pixel value RLt _mn of the target pixel position (i _m , j _n ) of the RLt _c plane data, first, the pixel value extraction unit 231 of the image processing unit 205 is identical to the Rn plane data. A pixel value Rn _mn is extracted from the pixel position (i _m , j _n ). Next, the luminance value extracting unit 232 of the image processing section 205, the same pixel position of Lt plane data _(i m, _{j n)} the luminance value _{Lt mn} from the same pixel position of Rt plane data _{(i m, j} n) The luminance value Rt _mn is extracted from. Then, the calculation unit 233 of the image processing unit 205 adds a term relating to the three-dimensional adjustment parameter C to the difference between the pixel value RLt _mn to be calculated and the extracted pixel value Rn _mn as the difference between the extracted luminance values Lt _mn and Rt _mn. The pixel value RLt _mn is calculated so as to maintain a correlation with the multiplied value. Specifically, it is calculated by the following equation (3). However, the three-dimensional adjustment parameter C is preset in the range of 0 <C <0.5.
RLt _mn -Rn _mn = (1 / 2-C) (Lt _mn -Rt _mn ) (3)

Similarly, the target pixel position of RRT plane data _(i m, _{j n)} may be calculated pixel value _{RRT mn} of calculating unit 233, the difference between the pixel values _{Rn mn} and the extracted pixel values _{RRT mn} to be calculated The pixel value RRt _mn is calculated so as to maintain a correlation with a value obtained by multiplying the difference between the extracted luminance values Lt _mn and Rt _mn by a term relating to the stereo adjustment parameter C. Specifically, it is calculated by the following equation (4). However, the three-dimensional adjustment parameter C here has the same value as C in Expression (3).
RRt _mn -Rn _mn = (1 / 2-C) (Rt _mn -Lt _mn ) (4)

The image processing unit 205 sequentially executes such processing from (1, 1) which is the pixel at the left end and the upper end to (i ₀ , j ₀ ) which is the coordinates at the right end and the lower end. In the examples of the above formulas (3) and (4), (1 / 2−C) is defined as the term relating to the stereo adjustment parameter C, but the pixel value RRt _mn to be calculated and the extracted pixel value Rn _mn The correlation between the difference and the difference between the extracted luminance values Lt _mn and Rt _mn can be changed as appropriate. In consideration of parameters such as the amount of eccentricity of the opening of the parallax pixel, the size, and the relative relationship with the opening of the pixel without parallax, the proportionality coefficient is changed, or a constant is added as a correction term, The correlation may be adjusted as appropriate. The above relationship is the same even if the pixel values to be calculated are the pixel values RRt _mn , GLt _mn , GRt _mn , BLt _mn , BRt _mn .

When the generation processing of RLt _c plane data and RRt _c plane data which are red parallax planes is completed, generation processing of GLt _c plane data and GRt _c plane data which are green parallax planes is executed next. Specifically, the pixel same pixel position _(i m, _{j n)} of Rn plane data in the above description, instead of extracting the pixel values _{Rn mn} from the same pixel position of Gn plane data _(i m, _{j n)} from The value Gn _mn is extracted and processed in the same way. Further, when the generation processing of the GLt _c plane data and the GRt _c plane data which are green parallax planes is completed, the generation processing of the BLt _c plane data and BRt _c plane data which are blue parallax planes is executed next. Specifically, the pixel same pixel position _(i m, _{j n)} of Rn plane data in the above description, instead of extracting the pixel values _{Rn mn} from the same pixel position of Bn plane data _(i m, _{j n)} from The value Bn _mn is extracted and processed in the same way.

Through the above processing, left-view color image data (RLt _c- plane data, GLt _c- plane data, BLt _c- plane data) and right-view color image data (RRt _c- plane data, GRt _c- plane data, BRt _c- plane data) Is generated. That is, the color image data of the left viewpoint and the right viewpoint can be acquired by a relatively simple process as a virtual output that does not actually exist as a pixel of the image sensor 100.

  Moreover, since the three-dimensional adjustment parameter C can be changed, the amount of parallax can be adjusted while maintaining the blur amount of the 2D color image due to the non-parallax pixels. Therefore, if these image data are played back by a playback device that supports 3D images, the user can view 3D video with a three-dimensional effect adjusted appropriately as a color image. In particular, since the processing is simple, it is possible to generate image data at high speed and to deal with moving images. The generated left-view color image data is the left-view parallax image data derived from the Lt plane data, and the generated right-view color image data is the right-view parallax image data derived from the Rt plane data. It may be recorded in association with. In this way, by recording the generated image data so as to be related to the image data derived from it, it is possible to easily manage the image during reproduction. For the association, for example, a file name is described as related image data in each header information. In this case, the image processing unit 205 plays a role as an adding unit that adds related information.

  In the above description, if parallax pixels are evenly allocated to all RGB pixels on the actual image sensor 100, high-quality color image data with good color reproducibility can be obtained while being a 3D image. However, it can be said that high-quality 3D color image data according to this can be obtained by performing the above processing even if such pixels are not actually provided. In addition, since it is not necessary to allocate parallax pixels to RGB pixels as actual pixels, the quality of other plane data can be improved accordingly.

  Next, the above processing will be described from the viewpoint of light intensity distribution. FIG. 26 is a diagram for explaining a change in the light intensity distribution. FIG. 26A shows the output values of the parallax Lt pixel and the parallax Rt pixel, which are W pixels, when the subject luminous flux is received from an object point located at a position deviated from the focal position by a certain amount. It is a graph. These output values are luminance values not including color information. Further, as described above, since the output value of the pixel is proportional to the light intensity, it can be said that the graph represents the light intensity distribution.

  FIG. 26B shows a value obtained by subtracting the output value of the parallax Rt pixel from the output value of the parallax Lt pixel in FIG. 26A and a value obtained by subtracting the output value of the parallax Lt pixel from the output value of the parallax Rt pixel. These are graphs arranged by multiplying (1 / 2-C), respectively. In the example shown in the figure, C = 0.2 is adopted as the three-dimensional adjustment parameter C. These curves correspond to the Lt modulation curve 1913 and the Rt modulation curve 1914 of FIG.

  FIG. 21C is a graph in which output values of R pixels, G pixels, and B pixels, which are pixels with no parallax, are arranged when the subject luminous flux from the object point in FIG. 20A is received. These output values are pixel values including color information. It can also be said that this graph also represents the light intensity distribution of each color.

  When the above-described processing is performed for each corresponding pixel, a light intensity distribution represented by the graph of FIG. As can be seen from the figure, the distribution is as if the output values from the actual RLt pixels, RRt pixels, GLt pixels, GRt pixels, BLt pixels, and BRt pixels are arranged. Note that the processing flow until the generation of parallax color image data is the same as the processing in FIG. In this case, in step S107, the three-dimensional adjustment parameter C is set in advance in a range of 0 <C <0.5.

  In the above description, the case where the image sensor 100 employs a B′-1 repeating pattern has been described as an example. That is, an example of generating 6 plane data of color image data of the left viewpoint and color image data of the right viewpoint by using the parallax image data as luminance image data that has W pixels and no color information. Explained. However, as described above, an enormous number of repetitive patterns can be set depending on how many colors of pixels the parallax pixels and non-parallax pixels are allocated to the color filter array. In the case of the image sensor 100 in which parallax pixels are assigned to a color filter of a specific color, the above processing is slightly changed to align 6 plane data of color image data of the left viewpoint and color image data of the right viewpoint. A specific procedure will be described below.

  FIG. 27 is a diagram illustrating plane separation processing in the image sensor 100 that employs another repetitive pattern. In the example shown in the figure, the image sensor 100 employs the above-described repeating pattern A-1. In the repeating pattern A-1, Gb pixels in the Bayer array are parallax Lt pixels, and Gr pixels are parallax Rt pixels.

From the RAW original image data output from such an image sensor 100, although R ₀ plane data and B ₀ plane data are separated as color image data, G ₀ plane data cannot be separated. Further, the Lt ₀ plane data and the Rt ₀ plane data separated as the parallax image data have green color information. In other words, it can be said that the parallax image data is luminance image data obtained by capturing a green wavelength component in the subject luminous flux. Therefore, each output value of these plane data can be handled as a luminance value.

  The above-described interpolation processing is performed on the separated plane data, and the empty grids existing in each are filled. FIG. 28 is a diagram for explaining the data structure of the RAW image data set after the interpolation processing.

  Interpolation processing for generating Rn plane data, Bn plane data, Lt plane data, and Rt plane data is the same as in the above example. In addition, the image processing unit 205 calculates an average value for each pixel corresponding to the GLt plane data and the GRt plane data, and generates Gn plane data.

Processing for generating RLt _c plane data and RRt _c plane data using parallax image data for Rn plane data, and generating GLt _c plane data and GRt _c plane data using parallax image data for Gn plane data The process and the process of generating BLt _c plane data and BRt _c plane data using parallax image data for the Bn plane data are the same as in the above-described example.

  In the above description, three primary colors, red, green and blue, are used as the primary colors constituting the color of the subject image. However, four or more colors including amber color may be used as primary colors. Instead of red, green, and blue, three primary colors that are complementary colors of yellow, magenta, and cyan can be used.

  In the above formulas (1) and (2), the range of the stereo adjustment parameter C is set to 0.5 <C <1. If C = 1, the color image data of the left viewpoint and the right viewpoint as virtual outputs of the parallax Lt pixel and the parallax Rt pixel that do not actually exist as the pixels of the image sensor 100 and have any of RGB color filters. Can be generated. If C = 0.5, 2D color image data can be generated as in the Gn plane data of FIG. If C = 0, the parallax image data is obtained by reversing the left and right luminance distributions. If values other than these are employed, more specific parallax image data such as reverse viewing can be obtained.

  In the processing in the flow of FIG. 22, the same value is consistently applied as the value of the three-dimensional adjustment parameter C. However, for example, the value of C may be changed for each region in accordance with the characteristics of the subject image. Specifically, C is changed according to the target pixel position (i, j). As for how to change C, it is possible to accept an instruction from the user in advance for the divided area, or it is possible to set an appropriate value for each area by face recognition technology or the like. By making the value of C variable, images with different stereoscopic effects can be obtained for each region even within the same image.

  In the above description, the color image data of the left viewpoint and the color image data of the right viewpoint are generated in pairs. That is, when applying the formula (1), if the stereo adjustment parameter C is set in the range of 0.5 <C <1, the formula (2) is obtained by substituting C and 1-C with respect to the formula (1). It becomes a replaced relationship. In this case, the color image data generated from Expression (1) is managed as color image data of the left viewpoint, for example, in association with Lt plane data, and the color image data generated from Expression (2) is The color image data is managed in association with, for example, Rt plane data. At this time, the image processing unit 205 functions as an adding unit that executes association.

  Further, in the above formulas (3) and (4), the range of the stereo adjustment parameter C is set to 0.5 <C <1. However, similarly to the case where various image data can be obtained by changing the value of the stereo adjustment parameter C in the above formulas (1) and (2), the stereo adjustment parameters of the formulas (3) and (4) are obtained. Various image data can be acquired by changing C as well.

  Further, when the above formulas (3) and (4) are applied to the flow of FIG. 22, not only the same value is consistently applied as the value of the three-dimensional adjustment parameter C but also, for example, in the feature of the subject image. In addition, the value of C may be changed for each region.

  In the above description, the color image data of the left viewpoint and the color image data of the right viewpoint are generated in pairs. That is, when applying the formula (3), if the stereo adjustment parameter C is set in a range of 0.5 <C <1, the formula (4) is obtained by substituting C and 1-C with respect to the formula (3). It becomes a replaced relationship. In this case, the color image data generated from Expression (3) is managed as color image data of the left viewpoint, for example, in association with Lt plane data, and the color image data generated from Expression (4) is The color image data is managed in association with, for example, Rt plane data. At this time, the image processing unit 205 functions as an adding unit that executes association.

  In the above description, for example, the pixel value extraction unit 231, the luminance value extraction unit 232, the calculation unit 233, and the like included in the image processing unit 205 have been described as functions of the respective components constituting the digital camera 10. Further, the control program that operates the control unit 201 and the image processing unit 205 can cause each hardware component of the digital camera 10 to function as a component that executes the above-described processing. In addition, these processes for generating color image data may be performed not by the digital camera 10 but by an external device such as a personal computer. In this case, an external device such as a personal computer functions as an image processing apparatus. For example, the image processing apparatus acquires RAW original image data and generates color image data. When the RAW original image data is acquired, the image processing apparatus also executes the above-described plane separation processing and plane data interpolation processing. The image processing apparatus may acquire plane data that has undergone interpolation processing on the imaging apparatus side.

  Next, another example (Example 2) will be described with respect to the above-described Example (Example 1). In the first embodiment, in order to generate a color image of the left viewpoint and a color image of the right viewpoint, the color plane information of the normal images Rn, Gn, and Bn is used, and an average image of the luminance image Lt of the left viewpoint and the luminance image Rt of the right viewpoint. On the other hand, when creating a color image of the left viewpoint, the luminance of the left viewpoint is maintained so that the ratio of the mixed image of the luminance image of the left viewpoint and the luminance image of the right viewpoint and the arithmetic average image is kept constant. The concept of generating a color image of the left viewpoint was shown by comparing the images with emphasis. In Example 2, another formula is presented. The expressions shown in Expression (1) and Expression (2) are replaced with the following arithmetic expressions.

Generate color image of left viewpoint
RLt = Rnx (Lt ^(1-d) * Rt ^d ) / √ (Lt * Rt)
GLt = Gnx (Lt ^(1-d) * Rt ^d ) / √ (Lt * Rt)
BLt = Bnx (Lt ^(1-d) * Rt ^d ) / √ (Lt * Rt)
Generate right-view color image
RRt = Rnx (Rt ^(1-d) * Lt ^d ) / √ (Lt * Rt)
GRt = Gnx (Rt ^(1-d) * Lt ^d ) / √ (Lt * Rt)
BRt = Bnx (Rt ^(1-d) * Lt ^d ) / √ (Lt * Rt)
However, the three-dimensional adjustment parameter d takes a value in the range of 0 ≦ d ≦ 0.5.

  When d = 0, the above expression is compared with the luminance image of the right viewpoint and the luminance image of the left viewpoint by keeping the ratio constant with respect to the geometric mean of the luminance image Lt of the left viewpoint and the luminance image Rt of the right viewpoint. A left-view color image and a right-view color image are generated. When d = 0.5, it is the same as the image without parallax.

  When the above equation is rewritten, the following relationship is satisfied.

Generate color image of left viewpoint
RLt / Rn = (Lt / Rt) ^(0.5-d)
GLt / Gn = (Lt / Rt) ^(0.5-d)
BLt / Bn = (Lt / Rt) ^(0.5-d)
Generate right-view color image
RRt / Rn = (Rt / Lt) ^(0.5-d)
GRt / Gn = (Rt / Lt) ^(0.5-d)
BRt / Bn = (Rt / Lt) ^(0.5-d)

  That is, the pixel value of the color image of the left viewpoint to be obtained is the ratio between the pixel value of the color image of the left viewpoint and the pixel value of the non-parallax image, and the luminance value of the left viewpoint luminance image and the luminance of the right viewpoint The value is obtained so as to have a correlation with the ratio between the luminance value of the image. In addition, the pixel value of the right-view color image to be obtained is determined by the ratio between the pixel value of the right-view color image and the pixel value of the non-parallax image. The value is obtained so as to have a correlation with the ratio between the luminance value of the image.

  Next, Example 3 is shown. Taking the logarithm of the formula shown in the second embodiment, it is equivalently expressed by the following formula.

Generate color image of left viewpoint
log (RLt) = log (Rn) + (1-d) * log (Lt) + d * log (Rt)-[log (Lt) + log (Rt)] / 2
log (GLt) = log (Gn) + (1-d) * log (Lt) + d * log (Rt)-[log (Lt) + log (Rt)] / 2
log (BLt) = log (Bn) + (1-d) * log (Lt) + d * log (Rt)-[log (Lt) + log (Rt)] / 2
Generate right-view color image
log (RRt) = log (Rn) + (1-d) * log (Rt) + d * log (Lt)-[log (Lt) + log (Rt)] / 2
log (GRt) = log (Gn) + (1-d) * log (Rt) + d * log (Lt)-[log (Lt) + log (Rt)] / 2
log (BRt) = log (Bn) + (1-d) * log (Rt) + d * log (Lt)-[log (Lt) + log (Rt)] / 2

  That is, when moving to an image processing space with logarithmic gradation, the arithmetic expression that keeps the ratio constant in the linear gradation image processing space is based on parallax modulation that keeps the difference constant in the logarithmic gradation space. Color images for the left and right viewpoints can be generated. By generalizing this idea, not only logarithmic gradation, but also gradation characteristics represented by powers such as square root and cubic root, and gamma space with arbitrary gradation characteristics, an operation to keep the difference constant, Similarly, the effect of applying parallax modulation can be obtained.

Flow chart 1) Color / parallax multiplexed mosaic image data input 2) Transition to gamma space by gradation conversion 3) Color and parallax image generation 4) Transition to original color space by inverse gradation conversion 5) Output color space Conversion

Processing Procedure 1) Color / Parallax Multiplexed Mosaic Image Data Input A single-panel mosaic image in which colors and parallax are multiplexed, which is obtained by dividing a Bayer array type G pixel into right parallax and left parallax, is input. This is represented as M [i, j]. Each pixel value is linear gradation data having a value proportional to the exposure amount.
2) Transition to gamma space by gradation conversion Perform gradation conversion on the mosaic image and shift to gamma space.
M [i, j] → M ^Γ [i, j]

によって行われる。 Actually, the nonlinear transformation y = f (x) is applied to the input pixel value x so as to be the output pixel value y. As examples of the characteristics of the non-linear transformation, the following various cases are conceivable. However, it is assumed that the input signal is x and the output signal is y, and both the gradation of the input signal and the gradation of the output signal are defined in the range [0, 1]. The gradation curve (gamma curve) is defined so that the input / output characteristics pass through (x, y) = (0, 0) and (1, 1). If the maximum value of the actual input gradation X is Xmax and the maximum value of the output gradation Y is Ymax, x = X / Xmax, y = Y / Ymax, and gradation conversion

Is done by.

b)オフセット付き平方根階調特性
オフセット値εは、正の定数である。USP7,957,588参照。
c)対数特性

係数kは正の定数である。
d)線形特性
y=x The following cases can be considered as examples of gradation characteristics.
a) Cubic root gradation characteristics

b) Square root tone characteristic with offset The offset value ε is a positive constant. See USP 7,957,588.
c) Logarithmic characteristics

The coefficient k is a positive constant.
d) Linear characteristics
y = x

3) Color and parallax image generation In the gamma space, similarly to the first embodiment, the parallax-free color images Rn ^Γ , Gn ^Γ and Bn ^Γ , the left viewpoint luminance image Lt ^Γ and the right viewpoint luminance image Rt ^Γ are generated. Thereafter, parallax modulation is applied by the following formula to generate a left-viewpoint color image and a right-viewpoint color image. The value in the gamma space is schematically represented by the index ^Γ .

Generate color image of left viewpoint
^{RLt Γ = Rn Γ + (1} -d) * Lt Γ + d * Rt Γ - (Lt Γ + Rt Γ) / 2
^{GLt Γ = Gn Γ + (1} -d) * Lt Γ + d * Rt Γ - (Lt Γ + Rt Γ) / 2
BLt ^Γ = Bn ^Γ + (1-d) * Lt ^Γ + d * Rt ^Γ- (Lt ^Γ + Rt ^Γ ) / 2
Generate right-view color image
^{RRt Γ = Rn Γ + (1} -d) * Rt Γ + d * Lt Γ - (Lt Γ + Rt Γ) / 2
^{GRt Γ = Gn Γ + (1} -d) * Rt Γ + d * Lt Γ - (Lt Γ + Rt Γ) / 2
^{BRt Γ = Bn Γ + (1} -d) * Rt Γ + d * Lt Γ - (Lt Γ + Rt Γ) / 2
However, the three-dimensional adjustment parameter d takes a value in the range of 0 ≦ d ≦ 0.5.

  When the above equation is rewritten, the following relationship is satisfied.

Generate color image of left viewpoint
RLt ^Γ -Rn ^Γ = (0.5-d) * (Lt ^Γ -Rt ^Γ )
GLt ^Γ -Gn ^Γ = (0.5-d) * (Lt ^Γ -Rt ^Γ )
BLt ^Γ -Bn ^Γ = (0.5-d) * (Lt ^Γ -Rt ^Γ )
Generate right-view color image
RRt ^Γ -Rn ^Γ = (0.5-d) * (Rt ^Γ -Lt ^Γ )
GRt ^Γ -Gn ^Γ = (0.5-d) * (Rt ^Γ -Lt ^Γ )
BRt ^Γ -Bn ^Γ = (0.5-d) * (Rt ^Γ -Lt ^Γ )

  That is, the pixel value of the color image of the left viewpoint to be obtained is the difference between the pixel value of the color image of the left viewpoint and the pixel value of the non-parallax image, and the luminance value of the luminance image of the left viewpoint and the luminance of the right viewpoint The value is obtained so as to have a correlation with the difference between the luminance value of the image. In addition, the pixel value of the color image of the right viewpoint to be obtained is the difference between the pixel value of the color image of the right viewpoint and the pixel value of the non-parallax image. The value is obtained so as to have a correlation with the difference between the luminance value of the image.

4) Transition to the original color space by inverse gradation conversion By applying inverse gradation conversion from the gamma space to the linear gradation space, the original color space is restored. Apply to necessary color image data. A left-view color image and a right-view color image are created.

Left view color image
RLt ^Γ [i, j] → RLt [i, j]
GLt ^Γ [i, j] → GLt [i, j]
BLt ^Γ [i, j] → BLt [i, j]
Right-view color image
RRt ^Γ [i, j] → RRt [i, j]
GRt ^Γ [i, j] → GRt [i, j]
BRt ^Γ [i, j] → BRt [i, j]

5) Conversion to output color space Color conversion and output gradation conversion are performed on the completed left-viewpoint color image and right-viewpoint color image to generate each output color image. For example, conversion to sRGB color space.

  In addition, although the mosaic image including parallax showed an example of the primary color Bayer arrangement, even if these color filters are replaced with a complementary color system, a complementary color image with a right parallax and a complementary color image with a left parallax are generated in the same principle. it can.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 10 Digital camera, 20 Shooting lens, 21 Optical axis, 30, 31 Subject, 100 Image sensor, 101 Micro lens, 102 Color filter, 103 Aperture mask, 104 Aperture, 105 Wiring layer, 106 Wiring, 107 aperture, 108 Photoelectric conversion Element, 109 substrate, 110 Repeat pattern, 120 Image sensor, 121 Screen filter, 122 Color filter part, 123 Aperture mask part, 201 Control part, 202 A / D conversion circuit, 203 Memory, 204 Drive part, 205 Image processing part, 207 Memory card IF, 208 operation unit, 209 display unit, 210 LCD drive circuit, 211 AF sensor, 220 memory card, 231 pixel value extraction unit, 232 luminance value extraction unit, 233 calculation unit, 322 center line, 1801, 1802, 1 03, 1804, 1805, 1807, 1808 Distribution curve, 1806, 1809 Composite distribution curve, 1901 Lt distribution curve, 1902 Rt distribution curve, 1903 2D distribution curve, 1905 Adjustment Lt distribution curve, 1906 Adjustment Rt distribution curve, 1913 Lt modulation curve 1914 Rt modulation curve, 1915 distribution curve, 1916 adjustment Lt distribution curve, 1917 adjustment Rt distribution curve

Claims (11)

Reference image data generated by capturing the same scene, first parallax image data having a first parallax in one direction with respect to a subject image of the reference image data, and in a direction opposite to the one direction An image data acquisition unit for acquiring second parallax image data having two parallaxes;
The reference pixel value at the target pixel position of the reference image data, the first parallax luminance value at the target pixel position of the first parallax image data, and the second parallax luminance value at the target pixel position of the second parallax image data. extracted and, equation _{P 3 -P 0 = (1/} 2-C) (P 2 -P 1)
(P ₀ : reference pixel value, P ₁ : first parallax luminance value, P ₂ : second parallax luminance value, P ₃ : third parallax pixel value, C: real number (where C ≠ 0, 0.5, 1 ))
A calculation unit that calculates a third parallax pixel value having a third parallax different from the first parallax and the second parallax with respect to the subject image;
An image data generation unit that generates third parallax image data using the plurality of third parallax pixel values calculated by the calculation unit by sequentially moving the target pixel position with respect to an image region in the reference image data An image processing apparatus comprising:   The image processing apparatus according to claim 1, wherein each of the extracted reference pixel value, the first parallax luminance value, and the second parallax luminance value is a value after gamma conversion.   The image processing apparatus according to claim 1, wherein the calculation unit changes C in the calculation formula according to the target pixel position. The image data generation unit causes the calculation unit to calculate the first data as the third parallax image data calculated using C _k set in a range greater than 0 and less than 0.5 as C in the calculation formula; The image processing apparatus according to claim 1, wherein the second data as the third parallax image data calculated using 1−C _k as C in the calculation formula is generated in pairs.   The image processing apparatus according to claim 4, further comprising: an adding unit that associates the first data with the first parallax image data and associates the second data with the second parallax image data.   The reference image data is color image data, and the calculation unit calculates the third parallax pixel value for each of plain image data separated for each color component constituting the color image data. The image processing apparatus according to any one of 1 to 5.   The image processing apparatus according to claim 6, wherein the first parallax image data and the second parallax image data do not include color information of the color component. An image sensor for imaging the same scene;
An image pickup apparatus comprising the image processing apparatus according to claim 1,
The image data acquisition unit is an imaging apparatus that acquires the reference image data, the first parallax image data, and the second parallax image data output from the imaging element. The image sensor is
Two-dimensionally arranged photoelectric conversion elements that photoelectrically convert incident light into electrical signals;
An opening mask provided in one-to-one correspondence with each of at least a part of the photoelectric conversion element,
Of the n adjacent photoelectric conversion elements (n is an integer of 3 or more), the openings of the opening masks provided corresponding to at least two of the photoelectric conversion elements are in the cross-sectional area of the incident light. Positioned so that light beams from mutually different partial areas corresponding to one parallax and the second parallax pass, and a photoelectric conversion element group including the n photoelectric conversion elements as a set is periodically arranged. The imaging device according to claim 8.   10. The imaging apparatus according to claim 9, wherein the set of the photoelectric conversion element group includes the photoelectric conversion element provided with the aperture mask that outputs the reference image data and passes the entire effective light flux of the incident light. . Reference image data generated by capturing the same scene, first parallax image data having a first parallax in one direction with respect to a subject image of the reference image data, and in a direction opposite to the one direction An image data acquisition step of acquiring second parallax image data having two parallaxes;
The reference pixel value at the target pixel position of the reference image data and the first parallax luminance value at the target pixel position of the first parallax image data while sequentially moving the target pixel position with respect to the image area in the reference image data , And the second parallax luminance value at the target pixel position of the second parallax image data is extracted, and the calculation formula P ₃ −P ₀ = (1 / 2−C) (P ₂ −P ₁ )
(P ₀ : reference pixel value, P ₁ : first parallax luminance value, P ₂ : second parallax luminance value, P ₃ : third parallax pixel value, C: real number (where C ≠ 0, 0.5, 1 ))
A calculation step of sequentially calculating a third parallax pixel value having a third parallax different from the first parallax and the second parallax with respect to the subject image;
An image processing program for causing a computer to execute an image data generation step of generating third parallax image data using the plurality of third parallax pixel values calculated in the calculation step.

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