JP4279775B2 - Optical distortion correction apparatus, optical distortion correction method, and imaging apparatus - Google Patents

Description

  The present invention relates to an optical distortion correction apparatus and an optical distortion correction method, and more particularly, to an optical distortion correction apparatus and an optical distortion correction apparatus that correct optical distortion of image data obtained by photographing a subject via an optical system having optical distortion. The present invention relates to a distortion correction method and an imaging apparatus.

  2. Description of the Related Art Conventionally, an imaging device, particularly a digital camera, obtains image data of a subject image by forming a subject image on an imaging element such as a CCD through an optical system by imaging. In such an imaging apparatus, it is known that optical distortion (distortion) due to distortion of the optical lens occurs. Optical distortion is divided into two types: “pincushion type” that displays the corners of the image extending outward, and “barrel type” that displays the corners shrinking, both of which are distorted depending on the distance from the optical center. The amount is determined.

  As a technique for correcting such an optical distortion, for example, in the technique disclosed in Patent Document 1, a subject image is displayed by arranging a plurality of pixels arranged in a horizontal direction in a plurality of pixels arranged in a horizontal direction. The image data to be stored is stored, and the image of the stored image data is divided into a plurality of strip regions in the vertical direction so that the horizontal width becomes a predetermined number of processing pixels. For each pixel column in the region, for each pixel column in the vertical direction in each strip region, the pixel value of each pixel from the pixel located at the head is stored for each pixel column in the predetermined direction in each strip region A technique is known that corrects optical distortion in both the horizontal direction and the vertical direction based on the pixel values of the pixels in each pixel column read out from the pixel. When all the pixel columns included in the first strip area have been read, each pixel column in the next strip area is read out. At this time, at the top in the horizontal direction of each pixel column in the previously processed strip area. The position moved in the horizontal direction by a predetermined number of pixels from the positioned pixel is set at the top in the horizontal direction of the next strip area, and the pixels in each pixel column in the next strip process are read out. Optical distortion correction corresponds to the coordinates (x, y) of the image data when there is no optical distortion (after correcting the optical distortion) where the horizontal direction is the X-axis direction and the vertical direction is the Y-axis direction. The coordinates (X, Y) of the image data before the optical distortion correction is obtained, and the pixel value of the pixel of the image data before the optical distortion correction corresponding to the obtained coordinates (X, Y) is optically calculated. This is done by setting the pixel value of the pixel at the coordinates (x, y) of the image after distortion is corrected. At this time, there is often no pixel corresponding to the image coordinates (X, Y) of the image data having optical distortion, and in fact, X near the coordinates (X, Y) of the image before correction of the optical distortion. The pixel value is obtained by interpolating the pixel values of the pixels adjacent in the axial direction and the Y-axis direction using the nearest neighbor interpolation method, the linear interpolation method, or the like.

As described above, in order to correct the optical distortion, the nearest neighbor interpolation method or the like based on the pixel values of the pixels adjacent to the X-axis direction and the Y-axis direction in the vicinity of the coordinates (X, Y) of the image before the optical distortion correction, Since it is necessary to obtain the pixel value of the coordinate (x, y) of the image after optical distortion correction by interpolating using a linear interpolation method or the like, the optical distortion correction processing of the image data in one strip process is completed. Then, when correcting the optical distortion of the image data of the next strip processing, an area overlapping the number of pixels necessary for correction is provided between the strip area corrected last time and the strip area to be corrected next. The following strip area is defined. In the conventional technique, the amount of movement from the first pixel of the strip area processed last time to the first pixel of the next strip area is constant, and the number of pixels necessary for correction is the same as the maximum optical distortion amount in the predetermined direction of the image data. A small number of pixels corresponding to the minimum optical distortion amount is determined as a distance (amount of movement) between the leading pixels of each strip region so that the strip regions are set to overlap.
JP 2003-333588 A

  However, as the amount of optical distortion in the predetermined direction increases, the pixel value of the pixel at the coordinate of the image after correcting the pixel value of the pixel located at the coordinate from the coordinates of the image before the optical distortion correction at a position further away in the predetermined direction. Therefore, in the strip area where the amount of optical distortion in the predetermined direction is large, an area overlapping with the previously corrected strip area is required more than the strip area where the amount of optical distortion is small. In a small strip region, the pixel value of the pixel located at the coordinate is corrected from the coordinates of the image before the optical distortion correction at a position closer to the predetermined direction than the strip region having a large amount of optical distortion. Therefore, it is not necessary to have a large area overlapping the strip area corrected last time. However, in the prior art, the amount of optical distortion is small because the amount of movement in the predetermined direction between the strip regions is constant in any strip region at any position on the image without depending on the amount of optical distortion in the predetermined direction. Even in the strip area including the position on the image, if the same amount of movement as the strip area including the position on the image with a large amount of optical distortion is moved, more areas overlap more unnecessary, and more strip areas are added to the image of the image data. Since it is necessary to set, there is a problem that the processing speed of the optical distortion correction processing is reduced as the number of pixels of the image data is increased.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an optical distortion correction apparatus, an optical distortion correction method, and an imaging apparatus that can efficiently perform optical distortion correction. .

The optical distortion correction apparatus according to the present invention is image data obtained by photographing a subject through an optical system having aberration, and intersects a predetermined pixel row in which a plurality of pixels are arranged in a predetermined direction. A storage unit that stores image data for displaying an image arranged in a plurality of rows in the direction of the image, and a pixel at the upstream end in a predetermined direction of the pixel column from the image data stored in the storage unit. A strip area is set in a direction intersecting with the predetermined direction in the previous period so that the width in the predetermined direction is a predetermined number of pixels, and the number of pixels corresponding to the input movement amount is sequentially set in the predetermined direction. Moving the pixel value of each pixel in each strip area in the predetermined direction for each pixel column in each strip area, and correcting the optical distortion of the read image data; By Based on the maximum optical distortion amount in the predetermined direction of the image data in the strip area processed last time, the movement amount is calculated for each strip area so as to decrease as the maximum optical distortion amount increases, and the calculated movement amount And a moving amount calculating means for each strip area for inputting the value to the correcting means.

  In the optical distortion correction, when there is no pixel located at the position on the image before the optical distortion correction, the pixel value of this pixel is the optical value of each pixel of the image data read for each strip area. It is obtained by interpolating from pixel values of pixels adjacent to the predetermined direction of the position on the image before distortion correction and the direction intersecting the predetermined direction. For this reason, each strip region has a different position on the image, that is, a different distance from the center of the image, and therefore includes a maximum amount of optical distortion in the X-axis direction that differs for each strip region. Specifically, the strip area closer to the center position has a smaller maximum optical distortion amount in a predetermined direction. Therefore, even if the overlapping area of each strip area is set to be smaller as the optical distortion amount is larger, the optical distortion is corrected. The strip area can be set so as to include pixels necessary for performing the above.

Therefore, the movement amount calculation means of the optical distortion correction apparatus of the present invention reduces the larger the maximum optical distortion amount based on the maximum optical distortion amount in the predetermined direction of the image data in the strip area processed last time. The movement amount is calculated for each strip area, and the calculated movement amount is input to the correction unit. The correction means sets the position moved so that the movement amount from the first pixel of the strip area corrected last time becomes smaller as the maximum optical distortion amount in the predetermined direction in the strip area to be corrected becomes larger, as the first pixel. The next strip area is set, and optical distortion of the image data in the set strip area is corrected.

  As described above, since the amount of movement to the strip area to be processed next can be calculated based on the maximum optical distortion amount in the predetermined direction for each strip area, it is set to the image of the image data stored in the storage means. Since the number of strip regions to be reduced can be further reduced as compared with the optical distortion correction apparatus of the first invention, the number of pixels read from the image data stored in the storage means can be further reduced, and the optical efficiency can be improved. Distortion correction can be performed.

The movement amount calculating means for each strip movement amount of the optical distortion device according to the present invention is upstream of a predetermined number of pixels corresponding to the maximum optical distortion amount in the predetermined direction of the strip area from the downstream end portion of the strip area in the predetermined direction. The movement amount may be calculated so that the position moved to the side becomes the position of the first pixel in the predetermined direction of the strip area to be processed next.

Further, the movement amount calculation means for each strip movement amount of the optical distortion correction apparatus of the present invention calculates for each strip region upstream in the predetermined direction from the central strip region including the center position of the image corresponding to the center of the optical system. When the strip area downstream of the central strip area in the predetermined direction is a strip area to be processed next, movement of the corresponding strip area stored in the movement amount storage means is included. The amount of movement can be calculated by reading the amount.

  The amount of optical distortion included in the image data of each strip area is the same value that is symmetrical in a predetermined direction about the center of the image, so the movement amount calculated for each strip area upstream of the image center in the predetermined direction is moved. If the movement amount of the strip area stored in the amount storage means and the strip area on the downstream side in the predetermined direction from the center of the image is calculated, the movement amount of the strip area at the corresponding position stored in the movement amount storage means is read. The optical distortion correction amount can be performed well, and the optical distortion correction process can be performed at high speed.

Optical distortion correction can be performed efficiently by the following optical distortion method. Specifically, in the optical distortion correction method according to the second aspect of the present invention, a pixel array in which a plurality of pixels are arranged in a predetermined direction, which is image data obtained by photographing a subject through an optical system having aberration. Are stored in a plurality of columns in a direction intersecting the predetermined direction, and image data for displaying an image is stored. From the stored image data, a pixel at an upstream end in a predetermined direction of the pixel column is set as a top pixel. A strip area is set in a direction intersecting with the predetermined direction in the previous period so that the width in the predetermined direction is a predetermined number of pixels, and the number of pixels corresponding to the input movement amount is sequentially set in the predetermined direction. The pixel value of each pixel in each strip region is read out in the predetermined direction for each pixel column in each strip region, optical distortion of the read image data is corrected, and the previously corrected strip region in the strip region is corrected. Of image data Based on the maximum optical distortion amount in the predetermined direction, the movement amount is calculated for each strip region so that the movement amount decreases as the maximum optical distortion amount increases, and the calculated movement amount is input to the correction unit. The amount of movement is calculated every time.

Further, by applying the optical distortion correction apparatus of the present invention to an imaging apparatus, it is possible to provide an imaging apparatus that can perform optical distortion correction efficiently. Specifically, the imaging apparatus of the second invention is image data obtained by photographing a subject through an optical system having aberration, and the pixel array in which a plurality of pixels are arranged in a predetermined direction A storage unit storing image data for displaying an image arranged in a plurality of columns in a direction crossing a predetermined direction, and a pixel at the upstream end in the predetermined direction of the pixel column from the image data stored in the storage unit A strip area in a direction intersecting with the predetermined direction in the previous period is set so that the width in the predetermined direction is a predetermined number of pixels, and the number of pixels corresponding to the input movement amount of the strip area Correction means that sequentially moves in a predetermined direction, reads the pixel value of each pixel in each strip region in the predetermined direction for each pixel column in each strip region, and corrects optical distortion of the read image data; Said correction means Therefore, based on the maximum optical distortion amount in the predetermined direction of the image data in the strip area processed last time, the movement amount is calculated for each strip area so as to decrease as the maximum optical distortion amount increases. Movement amount calculation means for each strip movement amount for inputting the amount to the correction means.

As indicated above, the optical distortion correction apparatus of the present invention, optical distortion method of the present invention, and according to the imaging apparatus of the present invention, based on the maximum optical distortion amount in a predetermined direction for each strip region, then Since the amount of movement to the strip area to be processed can be calculated, the number of strip areas to be set in the image of the image data stored in the storage means can be reduced, and from the image data stored in the storage means The number of pixels to be read can be further reduced, and optical distortion correction can be performed efficiently.

  Embodiments in which the present invention is applied to a digital camera will be described below with reference to the drawings.

  As shown in FIG. 1, the digital camera 10 according to the present embodiment includes an optical unit 12 for forming a subject image, and a subject obtained by the optical unit 12 disposed behind the optical axis of the optical unit 12. CCD (Charge Coupled Device) 14 for converting the reflected light into analog image data indicating a photographed image and outputting it.

  The optical unit 12 is an optical unit 12 having optical distortion, and includes a zoom lens group, a focus lens (not shown), and a lens moving mechanism that moves each of the zoom lens group and the focus lens in the optical axis direction. It is configured as a zoom lens capable of changing the focal length (magnification). The optical unit 12 is connected to the A / F control circuit 32, and the zoom lens group is moved in the optical axis direction so as to obtain a desired zoom magnification under the control of the A / F control circuit 32, and passes through the optical unit 12. The focus lens is configured to be movable in the optical axis direction so that incident light indicating the subject image formed is formed on the light receiving surface of the CCD 14.

  The digital camera 10 also includes an A / D converter 16 for converting analog image data indicating the subject image output from the CCD 14 into digital image data (hereinafter referred to as image data), and A / D conversion. For performing various digital signal processing such as white balance adjustment, gamma correction, sharpness correction, and YC conversion processing for converting RGB data into YC signals. A signal processor 22 and a main memory 38 for storing image data signal-processed by the signal processor 22 are provided. For the main memory 38, a large-capacity memory such as SRAM or SDRAM can be generally used.

  In addition, the digital camera 10 includes a distortion correction unit 24 (details will be described later) for correcting optical distortion of an image of image data obtained by photographing a subject through an optical unit 12 having optical distortion, and various information. And an LCD control unit 26 for performing display control of the LCD 18 for displaying an image of image data, and an external recording medium 28 for storing optical media such as smart media and IC cards in which optical distortion is corrected. A media control unit 30 for controlling reading and writing of various information; an I / F (interface) unit 34 connected to an operation means 20 such as a release button or a power switch that is pressed by a user when instructing shooting; The CPU 36 that controls the entire digital camera 10, various programs, and processing routines to be described later Chin includes a ROM40 which previously stores (see FIG. 7) or the like, the.

  The signal processor 22, the distortion correction unit 24, the LCD control unit 26, the media control unit 30, the A / F control circuit 32, the I / F unit 34, the CPU 36, the main memory 38, and the ROM 40 are a bus 42 such as a data bus. It is connected so that various data and signals can be exchanged via the network.

  As shown in FIG. 2, the distortion correction unit 24 reads the image data stored in the main memory 38, and inputs an input strip processing control unit 52 for DMA (Direct Memory Access) transfer to the arithmetic processing unit 54. An arithmetic processing unit 54 for correcting the optical distortion of the image with respect to the image data transferred from the strip processing control unit 52, and the corrected image data whose optical distortion has been corrected by the arithmetic processing unit 54 are transferred to the main memory 38. And an output strip processing control unit 58.

  Image data is obtained by arranging a plurality of pixels in a horizontal direction (X-axis direction) as a predetermined direction in a vertical direction (Y-axis direction) as a direction intersecting the predetermined direction. This is image data for displaying an image showing a subject image. As shown in FIG. 3, the input strip processing control unit 52 converts a pixel row stored in the main memory 38 in a horizontal direction (X-axis direction) into a vertical direction (Y-axis direction). The image data 80 capable of displaying an image showing a subject image obtained by photographing in a plurality of strips is divided into strips so that the width in the X-axis direction is the number of processing pixels of a predetermined processing unit. The arithmetic processing unit 24 divides the region 82 into each pixel region 82 for each pixel region 82 (hereinafter, referred to as a “small pixel column” in order to distinguish it from one pixel column in the entire image). DMA transfer to At the time of transfer, the input strip processing control unit 52 sequentially reads out the pixel value of each pixel by scanning the pixel value of each pixel in the image data for one small pixel column 84 in the horizontal direction (X-axis direction). The input strip processing control unit 52 sets a strip region 82 to be processed next, and a processing target strip / input start position for setting the position of the strip region 82 to be processed next in the X-axis direction. A setting unit 56 is connected. The input strip processing control unit 52 sequentially moves the strip region 82 to be processed in the X-axis direction, sequentially reads image data for a plurality of small pixel columns 84 in the next strip region 82, and When the transfer of the image data of each small pixel row 84 in the strip area 82 is completed, information indicating the input start position of the strip area 82 to be processed next set by the processing target strip / input start position setting unit 56 is displayed. Based on the information indicating the input start position instructed in the X-axis direction, the position moved in the X direction by the number of pixels is set to be the position of the first pixel in the next strip area 82. The process of sequentially reading the image data of each small pixel column 84 in the next strip area 82 is repeatedly executed. In this way, the input strip processing control unit 52 reads out each pixel value for each small pixel column 84 of each set strip region 82, whereby one end of the image of the image data 80 (the pixel 83 located at the image start point). ) To the other end (pixel 85 located at the end point of the image) facing each other.

The arithmetic processing unit 54 includes a line buffer 64 for storing the image data for one small pixel column 84 transferred from the input strip processing control unit 52, and the one small pixel column 84 stored in the line buffer 64. For the image data, a horizontal distortion correction unit 60 for correcting the optical distortion in the horizontal direction and the image data of each small pixel column 84 in which the horizontal optical distortion is corrected are stored for each small pixel column 84. Optical buffers in the vertical direction based on the image data of the line buffers 72 _{1 to} 72 ₃ and the plurality of small pixel rows 84 that have been corrected in the horizontal direction and stored in the line buffers 72 _{1 to} 72 _3. And a vertical distortion correction unit 62 for performing correction.

In the present embodiment, the vertical distortion correction unit 62 is provided with _three line buffers 72 _{1 to} 72 ₃ for the sake of simplification of description. However, a plurality of line buffers may be provided. The number is not limited to three.

In the present embodiment, each of the line buffers 70 and the line buffers 72 _{1 to} 72 ₃ has a capacity capable of storing image data composed of pixel values corresponding to one small pixel column 84. .

  Here, as the optical distortion, a “pincushion type” in which a corner portion of an image is extended and displayed as shown in FIG. 4A, and a corner portion that is contracted as shown in FIG. 4B. There are two types of “taru type”, and the amount of optical distortion is determined by the distance from the optical center. The optical distortion amount is shown by a non-linear curve (hereinafter referred to as a distortion curve) as shown in FIG. 4C. In the case of a positive optical distortion amount, each pixel is positioned from the center when there is no optical distortion. Since it shifts away from the position, it becomes a “pincushion type”, and in the case of a negative optical distortion amount, each pixel becomes a position that approaches the center from the position when there is no optical distortion, and thus becomes a “ball type”. The optical unit 12 determines which optical distortion is “pincushion type” or “barrel type”, and the optical unit 12 of the present embodiment has an aberration that causes optical distortion of the “barrel type”. Therefore, information indicating the barrel type is stored in the ROM 40 in advance.

  The optical distortion amount of the optical distortion can be approximated by a multi-order function with respect to the distance from the image center of each pixel. For example, when the distance from the optical center is d, the optical distortion amount Δd in the case of the barrel type is expressed by the following formula (1).

Δd = α × d + β × d ² + γ × d ³ + (1)
Here, d indicates the distance from the optical center, and α, β, and γ are coefficients.

When there is no optical distortion, that is, when the coordinates in the image of the image data in which the optical distortion in the horizontal direction and the vertical direction is corrected are (x, y) (x and y are integers), the coordinates (x, y) The coordinates (X, Y) of the image before optical distortion correction corresponding to are expressed by the following equation (2):
(X, Y) = (x × Δd, y × Δd), d = (x ² + y ² ) ^1/2 (2)
For this reason, the horizontal distortion correction unit 60 is based on the above formulas (1) and (2), and is included in the small pixel row 84 to be corrected in the image after optical distortion correction in the horizontal direction and the vertical direction. A coordinate (X, y) (hereinafter referred to as a pre-correction coordinate) of the image before optical distortion correction in the horizontal direction corresponding to the coordinate (x, y) is obtained. Next, the horizontal distortion correction unit 60 obtains the pixel value (pixel data) of the pixel corresponding to the pre-correction coordinates (X, y) from the image data of the small pixel row 84 transferred to the line buffer 70, and By using the obtained pixel value as a pixel value in which only the horizontal optical distortion of the coordinates (x, y) in the corrected image is corrected, the horizontal optical distortion is corrected.

The vertical distortion correction unit 62 calculates the optical distortion in the vertical direction corresponding to the coordinates (x, y) in the image after the distortion correction in the horizontal direction and the vertical direction based on the expressions (1) and (2). The coordinates before correction (x, Y) of the image before correction are obtained. Next, the vertical distortion correction unit 62 corrects the horizontal optical distortion in which the pixel values corresponding to the coordinates (x, Y) before correction are transferred to the respective line buffers 72 _{1 to} 72 ₃ . Is obtained from the image data of the small pixel column 84, and the obtained pixel value is used as the pixel value of the coordinate (x, y) in the corrected image, thereby correcting the distortion in the vertical direction.

  The horizontal distortion correction unit 60 and the vertical distortion correction unit 62 correct the horizontal and vertical optical distortions of the image data in the small pixel array 84.

  Usually, the coordinates (X, y) and (x, Y) before correction obtained by the above formulas (1) and (2) are not integer values, and there is a corresponding pixel in the image before correction. Often not. For this reason, the pixel value of the pixel corresponding to the obtained coordinates (X, y) of the image before correction is obtained from the pixel data of the actual pixels adjacent in the horizontal direction near the coordinates (X, y) of the image before correction. The pixel value of the pixel corresponding to the coordinates (x, Y) of the image before correction is interpolated and the pixel data of the actual pixels adjacent in the horizontal and vertical directions in the vicinity of the coordinates (x, Y) of the image before correction. From this, it is sufficient to obtain by interpolation using the nearest neighbor interpolation method, linear interpolation method or the like.

  Here, the direction in which the amount of optical distortion is generated is displayed as shown in FIG. 5 (A), the barrel type is displayed so that the corners of the image are contracted, and the pincushion type is shown in FIG. 5 (B). In the case of the barrel type, it is generated in a direction approaching the center, and in the case of the pincushion type, it is generated in a direction away from the center. Therefore, in the case of the barrel type, in order to correct the optical distortion, it is necessary to correct the optical distortion in a direction further away from the optical center 81 as the distance from the optical center 81 increases. As the distance from the center 81 increases, the optical distortion needs to be corrected in a direction closer to the image center.

  That is, as shown in FIG. 6, in the case of the barrel type, when the strip region 82 is positioned on the minus side in the X-axis direction from the strip region 82 including the optical center 81, the optical distortion correction direction is the strip region 82. When the strip region 82 is located at a position including the optical center 81 on the negative side of the X-axis direction, the optical distortion correction direction is on the positive side and the negative side of the strip region 82 in the X-axis direction. When the strip region 82 is positioned on the plus side in the X-axis direction from the strip region 82 including, the optical distortion correction direction is the plus side of the strip region 82 in the X-axis direction.

  In the case of the pincushion type, when the strip region 82 is positioned on the minus side in the X-axis direction from the strip region 82 including the optical center 81, the optical distortion correction direction is on the plus side in the X-axis direction of each strip region 82. When the strip region 82 is located at a position including the optical center 81, optical distortion correction is not necessary. When the strip region 82 is positioned on the plus side in the X-axis direction from the strip region 82 including the optical center 81, the optical distortion is not corrected. The correction direction is the negative side of each strip region 82 in the X-axis direction.

  That is, in the barrel type, on the negative side (the anti-reading direction side) of the image of the image data 80 from the optical center 81 in the X-axis direction, the pixels (hereinafter referred to as correction pixels) that are necessary for correction are located on the anti-reading direction side of each strip region 82. The strip area 82 needs to be set so as to include the margin 87), and on the plus side (reading direction side) of the optical center 81 in the X-axis direction of the image of the image data 80, the reading direction side of each strip area 82 is required. It is necessary to set the strip area 82 so as to include the margin 87. Further, in the strip region 82 including the optical center 81, it is necessary to set the strip region so as to include the margin 87 at both ends in the X-axis direction of the strip region 82.

  On the other hand, in the pincushion type, on the opposite side of the image of the image data 80 from the optical center 81 in the X-axis direction (on the side opposite to the reading direction), a margin 87 is included on the reading direction side of each strip region 82. The strip area 82 needs to be set, and on the plus side (reading direction side) from the optical center 81, the strip area 82 needs to be set so as to include the margin 87 on the side opposite to the reading direction of each strip area 82.

  In the processing target strip / input start position setting unit 56, the strip region 82 to be read next by the input strip processing control unit 52 is not the strip region 82 to be processed next to the strip region 82 including the center position. Sometimes, the position on the minus side in the X-axis direction is equal to the number of pixels corresponding to the maximum optical distortion amount in the X-axis direction of the image data from the downstream end (plus side) of the strip region 82 corrected last time. The input start position of the next strip area 82 is determined so as to be the position of the first pixel of the 82 strip area to be corrected. Further, the processing target strip / input start position setting unit 56 uses the input strip processing control unit 52 to make the strip region 82 to be read next the strip region 82 to be processed next to the strip region 82 including the center position. Is equal to the number of pixels corresponding to the maximum optical distortion amount in the X-axis direction of the image data in the strip area 82 including the optical center 81 from the downstream end in the X-axis direction of the strip area 82 including the optical center 81. The input start position of the next strip area 82 is determined so that the position on the minus side in the X-axis direction becomes the position of the first pixel of the 82 strip area to be corrected next.

  Therefore, at the time of optical distortion correction processing, the input strip processing control unit 52 determines the start position so that each strip region 82 has an overlapping region 87 as shown in FIG. 7A, and FIG. As shown in FIG. 5, the image data of each strip area 82 is transferred from the input strip processing control unit 52 to the arithmetic processing unit 54 so as to have an overlapping area 87, and the optical distortion in the horizontal and vertical directions is corrected by the arithmetic processing unit 54. As a result, as shown in FIG. 7C, image data in which all the margins 87 are removed from each transferred strip area 82 and the optical distortion is corrected is output to the main memory 38.

  Next, the operation of the digital camera 10 according to the above embodiment will be described.

  FIG. 8 shows a processing routine showing distortion correction processing executed by the CPU 36. When the image data is stored in the main memory 38 by shooting the subject, in step 100, the optical unit 12 reads the type of optical distortion of the optical unit 12 stored in the ROM 40, thereby causing the optical unit 12 to be a “barrel” and Which optical distortion of the “pincushion type” is read.

  In the next step 102, a movement amount calculation instruction signal is output to the processing target strip / input start position setting unit 56 so as to calculate the movement amount from the previously processed strip region 82 to the next strip region 82. When the movement amount calculation instruction signal is input, the processing target strip / input start position setting unit 56, according to the type of optical distortion, the maximum optical distortion amount in the X-axis direction of the image data obtained by photographing. Is calculated as a movement amount.

  In the next step 104, the processing target strip / input start position setting unit 56 uses the pixel at the end in the X-axis direction of the image data as the first pixel as the strip region 82 to be corrected next. The setting of the area 82 is instructed. Through the processing in step 104, the processing target strip / input start position setting unit 56 sets the strip area 82 so that the pixel located at the X-axis direction end of the image of the image data 80 is the first pixel, that is, the input start position. To do.

  In the next step 106, the pixel value of each pixel is sequentially read into the input strip processing control unit 52 for each small pixel column 84 in the strip area 82 set by the processing target strip / input start position setting unit 56. By transferring to the arithmetic processing unit 54, a transfer instruction signal is output to the input strip processing control unit 52 so that the image data for one strip area 82 is transferred. When the transfer instruction signal is input by the processing of step 106, the input strip processing control unit 52 has the input start position set by the processing target strip / input start position setting unit 56 as the first pixel in the strip region 82. For each small pixel column 84, the pixel values of the pixels of each small pixel column 84 are read in the X-axis direction, and the pixel values of the read pixels of each small pixel column 84 are used as image data for each small pixel column 84. The data is sequentially transferred to the arithmetic processing unit 54 for each small pixel column 84. The image data transferred to the arithmetic processing unit 54 is stored in the line buffer 64.

In the next step 108, the optical distortion instructing the horizontal distortion correction unit 60 to correct the optical distortion in the horizontal direction for the image data for one small pixel column 84 stored in the line buffer 64 by the processing in step 106. A correction instruction signal is output. When the optical distortion correction instruction signal is input, the horizontal distortion correction unit 60 corrects the horizontal optical distortion of the image data for one small pixel row 84 stored in the line buffer 64. Image data of one subpixel rows 84 minute optical distortion in the horizontal direction is corrected, the line buffer 72 ₁ to 72 _3, 1 small pixel columns 84 minutes image data is not yet stored line buffer 72 ₁ to 72 ₃ of the Are stored sequentially.

In the next step 110, all of the plurality of line buffers 72 ₁ to 72 _3, different when the image data of the small pixel columns 84 minutes is stored, the vertical distortion correction unit 62, a plurality of line buffers 72 ₁ to 72 Based on the image data in which the horizontal optical distortion of the plurality of different small pixel columns 84 stored in ₃ is corrected, an optical distortion instruction signal instructing the vertical optical distortion correction is output. When the optical distortion instruction signal is input, the vertical distortion correction unit 62 corrects the horizontal optical distortion of a plurality of different small pixel rows 84 stored in the plurality of line buffers 72 _{1 to} 72 ₃ . Based on the image data, the optical distortion in the vertical direction of each image data is corrected.

  In the next step 112, a DMA transfer instruction signal is output to the output strip processing control unit 58 for DMA transfer of the image data for each of the small pixel columns 84 in which both the horizontal and vertical optical distortions are corrected. When the DMA transfer instruction signal is input, the output strip processing control unit 58 corrects the horizontal optical distortion by the horizontal distortion correction unit 60 and corrects the vertical optical distortion by the vertical distortion correction unit 62. The image data for each small pixel column 84 thus transferred is transferred to the main memory 38 as image data for each small pixel column 84 whose optical distortion has been corrected.

  In the next step 113, it is determined whether or not the reading of all the small pixel rows 84 in the strip region 82 and the optical distortion correction processing have been completed. , Go to step 114.

  In the next step 114, it is determined whether or not all the optical distortion correction processes for the image of the image data 80 have been completed. If the determination is affirmative, this routine is ended. If the determination is negative, the routine proceeds to step 118.

  In step 118, it is determined whether or not the strip region 82 to be processed next is a strip region 82 adjacent to the downstream side in the reading direction of the strip region 82 including the optical center 81. Specifically, the determination in step 118 can be made by determining whether or not the optical center 81 (coordinate (0.0)) is included in the previously processed strip area 82.

  If the result in Step 118 is negative and the next processing target strip is the strip region 82 including the optical center 81 or the strip region 82 on the minus side in the X-axis direction from the strip region 82 including the optical center 81, go to Step 120. The process proceeds to the processing target strip / input start position setting unit 56 from the position of the pixel located at the upstream end in the reading direction in the X-axis direction of the strip region 82 processed last time by the movement amount calculated in step 102 above. After outputting the setting instruction signal so that the position moved downstream in the direction becomes the position of the first pixel of the strip area 82 to be processed next, that is, the input start position of the next strip area 82, the process proceeds to step 106. Return. When a setting instruction signal is input to the processing target strip / input start position setting unit 56 by the processing of step 106, the processing target strip / input start position setting unit 56 starts from the position of the first pixel of the strip region 82 processed last time. The input start position is set so that the pixel located at the position moved in the X-axis direction by the amount of movement calculated by the processing of step 102 becomes the first pixel of the strip area 82 to be processed next.

  On the other hand, if the result in step 118 is affirmative and the next processing target strip region 82 is the strip region 82 adjacent to the downstream side of the strip region 82 including the optical center 81 in the X-axis direction, the process proceeds to step 122. From the pixel located at the downstream end of the strip area 82 including the optical center 81 processed last time to the processing target strip / input start position setting unit 56, the strip area 82 including the optical center 81 is downstream in the X axis direction. After the input start position is set so that the pixel located at the position moved in the minus direction (counter-reading direction) by the margin 87 on the side becomes the first pixel of the strip area 82 to be processed next, the above step 106 is performed. Return to.

  As described above, the strip region 82 is sequentially moved in the X-axis direction to correct the optical distortion of the image data in each strip region 82. At the time of optical distortion correction, the previously corrected strip region 82 to be corrected The amount of movement from the first pixel in the X axis direction to the first pixel in the X axis direction of the next strip area 82 is adjacent to the downstream side in the X axis direction of the strip area 82 including the optical center 81 of the image corresponding to the center of the optical system. In the case where the strip region 82 that is changed only during the processing of the strip region 82 to be processed next and the strip region 82 to be corrected next is the strip region 82 adjacent to the strip region 82 including the optical center 81 in the X-axis direction, The number of pixels corresponding to the maximum amount of optical distortion in the X-axis direction of the image data in the strip region 82 including the optical center 81, that is, the pixel corresponding to the margin 87 in the strip region 82 including the optical center 81. Number only Since the position moved to the minus side in the axial direction can be changed to be the position of the first pixel in the predetermined direction of the strip area 82 to be corrected next, it corresponds to the direction of occurrence of optical distortion in each strip area 82 Since the amount of movement can be set, the number of strip areas to be set in the image of the image data obtained by shooting can be suppressed as compared with the case where the amount of movement of all the strip areas 82 is constant. The number of pixels read from the image data can be reduced by photographing, and optical distortion correction can be performed efficiently.

Therefore, as shown in FIG. 9A, in the conventional strip processing, the amount of movement of all strip processing is the same, but in the present invention, as shown in FIG. When the processing of the strip area 82 _a including the center 81 is completed, the movement amount is changed, the input start position of the strip area 82 _{a + 1 to be} processed next is reset, and the X of the strip area 82 a including the optical center 81 is reset. Since the position obtained by subtracting the margin 87 on the downstream side in the axial direction can be set as the input start position, it is possible to reduce the number of reading of the strip area 82 to be read for correction, so that the optical distortion correction processing can be speeded up. Therefore, the distortion process can be performed efficiently.

  In the process of FIG. 7 described above, the case where the type of optical distortion is a barrel type has been described. However, the distortion process can be efficiently performed by performing the same process on the pincushion mold.

[Second Embodiment]
In the first embodiment, the case where only the movement amount of the strip area 82 to be processed next to the strip area 82 including the optical center 81 is different from the movement amount of the other strip areas 82 has been described. In this embodiment, a case will be described in which the amount of movement from the previously processed strip area is calculated for each strip area.

  In addition, since the structure of this Embodiment is a structure similar to 1st Embodiment, it attaches | subjects the same code | symbol to the same part, and abbreviate | omits detailed description.

  As shown in FIG. 10, the distortion correction unit 24 of the present embodiment sets a strip area 82 to be processed next, instead of the processing target strip / input start position setting unit 56 of the first embodiment. In addition, a processing target strip / input start position setting unit 57 for calculating a movement amount for each set processing strip area 82 is included.

  The main memory 38 is fast in continuous access in the X-axis direction, but is slow in accessing discontinuous addresses. Generally, reading of image data from the main memory 38 by the distortion correction unit 24 has a high processing speed. Some pixel data arranged in the X-axis direction are collectively collected for the purpose of conversion.

  The amount of optical distortion changes depending on the distance from the optical center. The closer to the Y axis, the smaller the amount of distortion in the X axis direction, and the greater the distance from the Y axis, the greater the displacement. The number of correction pixels (hereinafter referred to as margin) 87 required for correction in any portion in one small pixel row 84 can be small, but the amount of margin 87 increases as the distance from the Y axis increases.

  Specifically, as shown in FIG. 5, the amount of optical distortion increases as the distance in the X-axis direction from the optical center 81 as the optical center increases. That is, when processing is performed by dividing into a plurality of strip regions 82, it is necessary to include more margin 87 regions in each strip region 82 as the distance in the X-axis direction of the optical center 81 increases. In the case of a mold with optical distortion, as shown in FIG. 5A, a strip area 82 including the optical center 81 requires a margin 87 area on both ends of the strip area 82 in the X-axis direction. At the same time, as the distance from the optical center 81 increases and the amount of optical distortion increases, the margin 87 included in the strip region 82 increases. When the optical distortion is a pincushion type, as shown in FIG. 5B, the strip area 82 including the optical center 81 does not require the margin 87 area, and the optical distortion of the strip area 82 increases as the amount of optical distortion increases. A large amount of the margin 87 area is required in the direction close to the center 81.

  Therefore, the processing target strip / input start position setting unit 56 calculates the nearest neighbor interpolation from the pixel values of the pixels adjacent to the coordinates (X, Y) in the X axis direction and the Y axis direction of the image before the optical distortion correction. Since it is necessary to obtain a pixel value by performing interpolation using a method or a linear interpolation method, when setting the next strip region 82, a larger amount of margin 87 is required as the amount of distortion increases. The starting position of the strip region 82 to be processed next is determined so that the region in the X-axis direction overlapping the processed strip region 82 becomes larger. Conversely, the smaller the amount of distortion, the smaller the required amount of margin 87 in the X-axis direction. Therefore, the area of the strip area 82 to be processed next is reduced so that the area overlapping with the previously processed strip area 82 becomes smaller. Define the starting position. That is, the processing target strip / input start position setting unit 56 increases the amount of movement from the previously processed strip region 82 to the strip region 82 to be processed in the next strip processing as the strip region including the optical center 81 becomes closer to the optical distortion. Since the amount is small, the amount is set to be large, and as the distance from the strip region including the optical center 81 is increased, the amount of optical distortion increases. Therefore, the amount of movement can be set to be small so that the overlapping region becomes larger.

  Next, the operation of the digital camera 10 according to the above embodiment will be described. The same numbers are assigned to the same processes as those in the first embodiment.

  In FIG. 11, in step 100, by reading the type of optical distortion of the optical unit 12 stored in the ROM 40, it is determined whether the optical unit 12 has a “coil type” or a “pincushion type”. read.

  In the next step 104, the processing target strip / input start position setting unit 56 uses the pixel at the end in the X-axis direction of the image data as the first pixel as the strip region 82 to be corrected next. The setting of the area 82 is instructed. Through the processing in step 104, the processing target strip / input start position setting unit 56 sets the strip area 82 so that the pixel located at the X-axis direction end of the image of the image data 80 is the first pixel, that is, the input start position. To do.

  In the next step 106, the pixel value of each pixel is sequentially read into the input strip processing control unit 52 for each small pixel column 84 in the strip area 82 set by the processing target strip / input start position setting unit 56. By transferring to the arithmetic processing unit 54, a transfer instruction signal is output to the input strip processing control unit 52 so that the image data for one strip area 82 is transferred. When the transfer instruction signal is input by the processing of step 106, the input strip processing control unit 52 has the input start position set by the processing target strip / input start position setting unit 56 as the first pixel in the strip region 82. For each small pixel column 84, the pixel values of the pixels of each small pixel column 84 are read in the X-axis direction, and the pixel values of the read pixels of each small pixel column 84 are used as image data for each small pixel column 84. The data is sequentially transferred to the arithmetic processing unit 54 for each small pixel column 84. The image data transferred to the arithmetic processing unit 54 is stored in the line buffer 64.

In the next step 108, the optical distortion instructing the horizontal distortion correction unit 60 to correct the optical distortion in the horizontal direction for the image data for one small pixel column 84 stored in the line buffer 64 by the processing in step 106. A correction instruction signal is output. When the optical distortion correction instruction signal is input, the horizontal distortion correction unit 60 corrects the horizontal optical distortion of the image data for one small pixel row 84 stored in the line buffer 64. Image data of one subpixel rows 84 minute optical distortion in the horizontal direction is corrected, the line buffer 72 ₁ to 72 _3, 1 small pixel columns 84 minutes image data is not yet stored line buffer 72 ₁ to 72 ₃ of the Are stored sequentially.

In the next step 110, all of the plurality of line buffers 72 ₁ to 72 _3, different when the image data of the small pixel columns 84 minutes is stored, the vertical distortion correction unit 62, a plurality of line buffers 72 ₁ to 72 Based on the image data in which the horizontal optical distortion of the plurality of different small pixel columns 84 stored in ₃ is corrected, an optical distortion instruction signal instructing the vertical optical distortion correction is output. When the optical distortion instruction signal is input, the vertical distortion correction unit 62 corrects the horizontal optical distortion of a plurality of different small pixel rows 84 stored in the plurality of line buffers 72 _{1 to} 72 ₃ . Based on the image data, the optical distortion in the vertical direction of each image data is corrected.

  In the next step 112, a DMA transfer instruction signal is output to the output strip processing control unit 58 for DMA transfer of the image data for each of the small pixel columns 84 in which both the horizontal and vertical optical distortions are corrected. When the DMA transfer instruction signal is input, the output strip processing control unit 58 corrects the horizontal optical distortion by the horizontal distortion correction unit 60 and corrects the vertical optical distortion by the vertical distortion correction unit 62. The image data for each small pixel column 84 thus transferred is transferred to the main memory 38 as image data for each small pixel column 84 whose optical distortion has been corrected.

  In the next step 113, it is determined whether or not the reading of all the small pixel rows 84 in the strip region 82 and the optical distortion correction processing have been completed, and if not, the process returns to step 106, and if affirmed, Proceed to step 114.

  In the next step 114, it is determined whether or not all the optical distortion correction processes for the image of the image data 80 have been completed. If the determination is affirmative, the routine is terminated. If the determination is negative, the routine proceeds to step 200.

  In step 200, the position of the strip area 82 read in the previous reading from the downstream end (plus side) in the reading direction (X axis direction) in the X axis direction by the margin 87 in the counter reading direction (minus side) is the next strip. The movement amount is calculated so as to be the first pixel of the area 82 (the input start position of the strip area 82 to be processed next).

  In the next step 202, the movement calculated in the above step 200 from the position of the pixel located at the upstream end in the reading direction in the X-axis direction of the strip area 82 processed previously is transferred to the processing target strip / input start position setting unit 56. After outputting a setting instruction signal so that the position moved to the downstream side in the X-axis direction by the amount becomes the position of the first pixel of the strip area 82 to be processed next, the process returns to step 106. When a setting instruction signal is input, the processing target strip / input start position setting unit 56 is located at a position moved in the X-axis direction by the calculated movement amount from the position of the first pixel of the strip area 82 processed last time. After setting the input start position so that the pixel becomes the first pixel of the strip area 82 to be processed next, the process returns to step 106.

  As the maximum distortion amount in the X-axis direction in the strip area 82 is reduced by the processing in step 202, the movement from the first pixel of the strip area 82 processed last time to the first pixel of the next strip area 82 is increased. The quantity can be determined.

  As described above, in the present embodiment, the movement amount to the strip region 82 to be processed next can be calculated based on the maximum optical distortion amount in the X-axis direction for each strip region 82. The number of strip regions 82 set in the image data obtained by the above can be further reduced as compared with the optical distortion correction method according to the first embodiment, so that the image data stored in the main memory 38 can be used. The number of pixels to be read can be further reduced, and optical distortion correction can be performed efficiently.

  That is, as shown in FIG. 12 (A), in the conventional strip processing, the amount of movement of all the strip processing is the same, but in the present invention, as shown in FIG. Since the amount of movement can be determined so that the amount of movement increases as the maximum distortion amount in the predetermined direction of the image data of the image data in the strip area decreases for each strip area 82, the amount of movement of the strip area 82 to be read for correction can be determined. Since the number can be further reduced, the speed of the optical distortion correction process can be increased, and the optical distortion correction process can be performed efficiently.

  In the processing flow of FIG. 7 described above, the case of the barrel mold has been described. However, the optical distortion correction process can be efficiently performed by performing the same process for the pincushion mold.

  Since the amount of optical distortion is determined according to the distance from the optical center 81, each strip region 82 has the same optical property so as to be symmetrical in the X-axis direction about the strip region 82 including the optical center 81. There is a pair of strip regions 82 having a distortion amount. That is, a strip region 82 including a margin 87 region that is the same as the margin 87 region of each strip region 82 on the minus side in the X-axis centering on the strip region 82 including the optical center 81 is also present on the plus side in the X-axis direction. .

  Therefore, in the above embodiment, the movement amount is calculated for each strip region 82. However, the calculated movement amount corresponding to each strip region 82 located on the minus side in the X-axis direction from the strip region 82 including the optical center 81 is calculated. The movement amount calculation of each strip area 82 having the corresponding optical distortion amount is stored in the memory not shown in the CPU 36, and the movement amount calculation of each strip area 82 having the corresponding optical distortion amount stored in the memory not shown in the figure. If the movement amount is used, the optical distortion correction process can be further performed at high speed.

It is a schematic diagram which shows schematic structure of the digital camera which concerns on 1st embodiment. It is a schematic diagram which shows the detailed structure of the distortion correction part which concerns on 1st embodiment. It is a schematic diagram which shows the reading method which reads the image of image data for every strip area | region. (A) is a schematic diagram showing optical distortion of a pincushion mold, (B) is a schematic diagram showing optical distortion of a barrel mold, and (C) shows distortion curves of the pincushion mold and the barrel mold. FIG. (A) is a schematic diagram showing a margin 87 generation direction for each strip region 82 according to the distance from the optical center 81 when correcting an image having a barrel-shaped optical distortion, and (B), It is a schematic diagram showing a margin 87 generation direction for each strip region 82 according to the distance from the optical center 81 when correcting an image having a pincushion type optical distortion. It is a schematic diagram which shows the optical distortion correction direction corresponding to the position of a strip area | region for every kind of optical distortion. It is a schematic diagram which shows an optical distortion correction process, (A) is a schematic diagram which shows setting the image of image data for every strip area | region 82, (B) is the image data read for every strip area | region 82 It is a schematic diagram which shows the overlapping state of these images, (C) is a schematic diagram which shows the image by which the optical distortion was correct | amended. It is a flowchart which shows the correction process of the optical distortion which concerns on 1st embodiment. (A) is a schematic diagram which shows the movement amount of the conventional strip area | region, (B) is a schematic diagram which shows the movement amount of the strip area | region which concerns on 1st embodiment. It is a schematic diagram which shows the detailed structure of the distortion correction part which concerns on 2nd embodiment. It is a flowchart which shows the correction process of the optical distortion which concerns on 2nd embodiment. (A) is a schematic diagram which shows the movement amount of the conventional strip area | region, (B) is a schematic diagram which shows the movement amount of the strip area | region which concerns on 2nd embodiment. (A) is a schematic diagram showing the amount of movement of the strip region in the case of the spool type in the second embodiment, and (B) is the movement of the strip region in the case of the barrel in the second embodiment. It is a schematic diagram which shows quantity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Optical unit 24 Distortion correction | amendment part 38 Main memory 52 Input strip process control part 54 Operation processing part 56 Process target strip and input start position setting part 57 Process target strip and input start position setting part

Claims (5)

  Image data obtained by photographing a subject through an optical system having aberration, and an image in which a plurality of pixels are arranged in a direction intersecting the predetermined direction. Storage means for storing image data for displaying
  From the image data stored in the storage means, the pixel at the upstream end in the predetermined direction of the pixel row is the first pixel and intersects the predetermined direction in the previous period so that the predetermined direction has a predetermined number of pixels. The strip area is set in the direction to be moved, and the number of pixels corresponding to the input movement amount is sequentially moved in the predetermined direction so that the pixel value of each pixel in each strip area is set in each strip area. Correction means for reading out each pixel column in the predetermined direction and correcting optical distortion of the read image data;
  Based on the maximum optical distortion amount in the predetermined direction of the image data in the strip area previously processed by the correction means, the movement amount is calculated for each strip area so as to decrease as the maximum optical distortion amount increases. A movement amount calculation means for each strip movement amount that inputs the calculated movement amount to the correction means;
  An optical distortion correction apparatus including:   The moving amount calculation means for each moving amount of the strip has a position moved upstream in the predetermined direction by the number of pixels corresponding to the maximum optical distortion amount in the predetermined direction of the strip region from the downstream end portion in the predetermined direction of the strip region processed last time. The optical distortion correction apparatus according to claim 1, wherein the movement amount is calculated so as to be a position of a first pixel in a predetermined direction of a strip area to be processed next.   The movement amount calculating means for storing the movement amount calculated for each strip area upstream in a predetermined direction from the central strip area including the center position of the image corresponding to the center of the optical system. When the strip area downstream in the predetermined direction from the central strip area is a strip area to be processed next, the movement amount is calculated by reading the movement amount of the corresponding strip area stored in the movement amount storage means. The optical distortion correction apparatus according to claim 1 or 2.   Image data obtained by photographing a subject through an optical system having aberration, and an image in which a plurality of pixels are arranged in a direction intersecting the predetermined direction. Store the image data to display
  From the stored image data, a pixel in a direction intersecting with the predetermined direction in the previous period such that the pixel at the upstream end in the predetermined direction of the pixel row is the first pixel and the width in the predetermined direction is a predetermined number of pixels. The strip area is set and the number of pixels corresponding to the input movement amount is sequentially moved in the predetermined direction so that the pixel value of each pixel in each strip area is changed to each pixel row in each strip area. Read in the predetermined direction every time, correct the optical distortion of the read image data,
  Based on the maximum optical distortion amount in the predetermined direction of the image data in the strip area corrected last time, the movement amount is calculated for each strip area so as to decrease as the maximum optical distortion amount increases, and the calculated movement amount Calculating the movement amount for each strip movement amount input to the correction means,
  Optical distortion correction method.   Image data obtained by photographing a subject through an optical system having aberration, and an image in which a plurality of pixels are arranged in a direction intersecting the predetermined direction. Storage means for storing image data for displaying
  From the image data stored in the storage means, the pixel at the upstream end in the predetermined direction of the pixel row is the first pixel and intersects the predetermined direction in the previous period so that the predetermined direction has a predetermined number of pixels. The strip area is set in the direction to be moved, and the number of pixels corresponding to the input movement amount is sequentially moved in the predetermined direction so that the pixel value of each pixel in each strip area is set in each strip area. Correction means for reading out each pixel column in the predetermined direction and correcting optical distortion of the read image data;
  Based on the maximum optical distortion amount in the predetermined direction of the image data in the strip area previously processed by the correction means, the movement amount is calculated for each strip area so as to decrease as the maximum optical distortion amount increases. A movement amount calculation means for each strip movement amount that inputs the calculated movement amount to the correction means;
  An imaging apparatus including:

Images