JP4207381B2 - Image processing apparatus, image processing method, and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing technique for an image composed of a plurality of pixels having a signal value with a predetermined range.
[0002]
[Prior art]
For image processing such as sharpness correction, processing is performed in which the amount of enhancement is calculated by a filter such as an unsharp mask or Laplacian, and this is added to the pixel value of each pixel of the original image. When the pixel value after processing exceeds the range, that is, exceeds white (255 for 8 bits), the pixel value is set to white.
[0003]
[Problems to be solved by the invention]
However, in the above-described sharpness correction, when the gain for calculating the enhancement amount is large, the number of whiteout pixels increases. However, as the proportion of white pixels in the image increases, the enhancement amount gain is suppressed. ing. In this case, sufficient sharpness correction with a desired gain cannot be performed.
[0004]
In addition, since still images are displayed one after another in moving images, whiteout is more conspicuous than in the case of only a still image, and processing for preventing whiteout is important.
[0005]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an image processing technique capable of preventing image deterioration due to overexposure while ensuring desired image processing.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of claim 1 is an image processing apparatus that performs image processing on an image composed of a plurality of pixels having a first signal value with a defined range, wherein (a) performs image processing on a predetermined pixel group according to the image, and processing means for performing image processing to generate a second signal value based on the first signal value, (b) a first intermediate of the range Setting means for setting a section from a value to one limit value as an end region; (c) whether or not the first signal value belongs to the end region; and the second signal value is the end portion A determination means for determining whether or not it belongs to an area; and (d) for the predetermined pixel group, when the determination means determines that the first signal value belongs to the end area, A first output control means for outputting a first signal value; (e) for the predetermined pixel group, By serial determination means, said first signal value is not belong to the said end regions, and when the second signal value is determined to belong to the end region, the away from one of the limit values ( 2 ) a second output control means for outputting a signal value not exceeding the set second intermediate value; and (f) the first signal value and the second signal value for the predetermined pixel group by the determination means. And a third output control means for outputting the second signal value when it is determined that both do not belong to the end region .
[0007]
According to a second aspect of the invention, in the image processing apparatus according to the first aspect of the invention, the first intermediate value is set to a fixed value.
[0008]
According to a third aspect of the present invention, in the image processing apparatus according to the first or second aspect of the present invention, (g) the first information is based on statistical information relating to the second signal value in the predetermined pixel group. Further provided is a determining means for determining the intermediate value.
[0009]
According to a fourth aspect of the present invention, in the image processing apparatus according to the third aspect of the present invention, the statistical information includes the number of pixels for which the processed signal value is close to the one limit value, and the predetermined pixel. Obtained based on the ratio to the total number of pixels in the group.
[0010]
According to a fifth aspect of the present invention, in the image processing device according to any one of the first to fourth aspects, the first intermediate value and the second intermediate value are equal.
[0011]
According to a sixth aspect of the present invention, in the image processing apparatus according to any one of the first to fifth aspects, the image is a frame of a moving image, and the brightness of the range is high when the image is reproduced. The said edge part area | region is set to the edge part used as the side.
[0012]
According to a seventh aspect of the present invention, in the image processing apparatus according to any one of the first to sixth aspects, the image processing performed by the processing means is processing relating to sharpness correction.
Further, the invention of claim 8 is an image processing method for performing image processing on an image composed of a plurality of pixels having a first signal value with a defined range, and (a) a predetermined value related to the image performs image processing on the pixel group, wherein the processing step of performing image processing to generate a second signal value based on the first signal value, one of the limitations from the first intermediate value of (b) the range a setting step of setting a section up to a value as an end region, (c) whether the first signal value belongs to the end region, whether or not the second signal value belongs to the end region A determination step for determining whether or not (d) for the predetermined pixel group , if it is determined in the determination step that the first signal value belongs to the end region, the first signal value a first output control step of outputting, for (e) the predetermined pixel group, wherein the determining step smell When it is determined that the first signal value does not belong to the end region and the second signal value belongs to the end region, the first signal value is set apart from the one limit value. A second output control step for outputting a signal value not exceeding two intermediate values; and (f) for the predetermined pixel group, in the determination step, both the first signal value and the second signal value are the end values. And a third output control step for outputting the second signal value when it is determined that it does not belong to the partial area .
According to a ninth aspect of the invention, in the image processing method according to the eighth aspect of the invention, the first intermediate value is set to a fixed value.
The invention according to claim 10 is the image processing method according to claim 8 or 9, wherein (g) the first information is based on statistical information relating to the second signal value in the predetermined pixel group. The method further includes a determination step of determining the intermediate value.
The invention according to claim 11 is the image processing method according to claim 10, wherein the statistical information includes the number of pixels in which the second signal value is in the vicinity of the one limit value, and the predetermined pixel. Obtained based on the ratio to the total number of pixels in the group.
According to a twelfth aspect of the present invention, in the image processing method according to any of the eighth to eleventh aspects, the first intermediate value and the second intermediate value are equal.
According to a thirteenth aspect of the present invention, in the image processing method according to any one of the eighth to twelfth aspects, the image is a frame of a moving image, and the brightness of the range is high when the image is reproduced. The said edge part area | region is set to the edge part used as the side.
According to a fourteenth aspect of the present invention, in the image processing method according to any one of the eighth to thirteenth aspects, the image processing performed in the processing step is processing relating to sharpness correction.
[0013]
According to a fifteenth aspect of the present invention, there is provided a computer-readable recording in which a program for causing a computer built in the image processing apparatus to execute the image processing method according to any of the eighth to fourteenth aspects is recorded. It is a medium .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
<First Embodiment>
<Configuration of main part of image processing apparatus>
FIG. 1 is a perspective view showing a main configuration of an image processing apparatus 1 according to the first embodiment of the present invention.
[0015]
The image processing apparatus 1 is configured as a personal computer, and includes a processing unit 2 having a box shape, an operation unit 3, and a monitor 4.
[0016]
The processing unit 2 is a part that performs image processing, and has an insertion unit 21 that inserts a recording medium 9 such as an optical disk on the front surface thereof.
[0017]
The operation unit 3 includes a mouse 31 and a keyboard 32, and receives an input operation on the image processing apparatus 1 from a user.
[0018]
The monitor 4 is displayed based on an instruction from the processing unit 2.
[0019]
FIG. 2 is a diagram illustrating functional blocks of the image processing apparatus 1.
[0020]
The processing unit 2 of the image processing apparatus 1 includes an input / output I / F 22 connected to the mouse 31, the keyboard 32, and the monitor 4, and a control unit 23 electrically connected to the input / output I / F 22. The processing unit 2 includes a storage unit 24 that is electrically connected to the control unit 23 and an input / output I / F 25.
[0021]
The input / output I / F 22 is an interface for controlling transmission / reception of data between the mouse 31, the keyboard 32 and the monitor 4 and the control unit 23.
[0022]
The storage unit 24 is configured as a hard disk, and stores an operation system (OS) 24a, an arithmetic processing program 24b for performing image processing, and the like.
[0023]
The input / output I / F 25 is an interface for inputting / outputting data to / from the recording medium 9 via the insertion unit 21.
[0024]
The control unit 23 includes a CPU 231 and a memory 232, and is a part that performs overall control of the operation of the image processing apparatus 1 by organically controlling the above-described units. Program data recorded on the recording medium 9 can be stored in the memory 232 of the control unit 23 via the input / output I / F 25. Thereby, the stored program can be reflected in the operation of the image processing apparatus 1.
[0025]
<Operation of Image Processing Apparatus 1>
FIG. 3 is a flowchart showing an image processing operation in the image processing apparatus 1. This operation is for performing sharpness correction using an unsharp mask, that is, enhancement processing, on an image constituted by a pixel array, and is automatically executed by the CPU 231 of the control unit 23.
[0026]
The image processing apparatus 1 can handle both still images and moving images. Here, a case where processing is performed on each frame image of a moving image will be considered. Although only one frame will be described below, the same processing is performed for each frame image. The same applies to other embodiments described later.
[0027]
Further, the pixel value (signal value) of each pixel to be subjected to the main image processing has a range (dynamic range) of 8 bits, that is, a lower limit value 0 to an upper limit value (limit value) 255. Note that the pixel value indicates a luminance value.
[0028]
In step S1, the color space is converted from RGB signals to HSL signals for each pixel.
[0029]
In step S2, each pixel (pixel group) forming an image is converted by an unsharp mask. Specifically, the pixel value of the pixel in the i row and j column of the pixel array forming the image is Kij, Aij is the local average value for this pixel, C is the gain coefficient for calculating the enhancement amount, and Hij is the pixel after processing. If it is a value, the calculation shown in the following equation 1 is performed.
[0030]
[Equation 1]
Hij = Kij + C (Kij-Aij)
In step S3, it is determined whether the pixel value Kij is a threshold value Th, for example, 230 or more. The pixel value corresponding to this threshold Th = 230 is a gray value of about 90%. If the pixel value Kij is greater than or equal to the threshold value Th, the process proceeds to step S4. If the pixel value Kij is smaller than the threshold value Th, the process proceeds to step S5.
[0031]
In step S4, Kij is substituted for the pixel value H'ij. This means that for the high-brightness pixels in the original image before processing that are equal to or higher than the threshold Th, the pixel value Kij before sharpness correction is substituted for the pixel value H′ij in order to respect the expression state of the original image.
[0032]
In step S5, it is determined whether or not the pixel value Hij is equal to or greater than a threshold value Th that is an intermediate value of the range and a fixed value. If the pixel value Hij is greater than or equal to the threshold Th, the process proceeds to step S6. If the pixel value Hij is smaller than the threshold Th, the process proceeds to step S7.
[0033]
In step S6, a threshold value Th that is an intermediate value of the range is substituted into the pixel value H′ij. This is a conversion for preventing overexposure.
[0034]
In step S7, the pixel value Hij is substituted for the pixel value H'ij.
[0035]
In step S8, the pixel value of each pixel in the image is updated with the processed pixel value H′ij, and then the color space is restored. That is, the color space is converted from the HSL signal to the RGB signal.
[0036]
The above operation will be described with reference to FIG.
[0037]
FIG. 4 is a diagram for explaining the processing operation of steps S5 to S7. Here, the horizontal axis regarding the graph of FIG. 4 indicates the pixel value Hij after sharpness correction, and the vertical axis indicates the pixel value H′ij after the whiteout prevention conversion.
[0038]
In the conversion function Fn, the linear functions F1 and F2 are connected at a point P (230, 230). Here, the linear function F1 is a straight line with H′ij = Hij, and the linear function F2 is a straight line with H′ij = 230. That is, a section having both ends of the threshold Th and one limit value (255) of the range (dynamic range) of the image signal is set as an end region (transformation region) TR that excludes the processed signal value. Has been. This end TR is set to an end on the high brightness side during reproduction of the image in the range of the image signal. The example considered here is a positive image. Therefore, when the pixel value Hij after image correction processing such as an unsharp mask enters the end region TR, the pixel value Hij is an intermediate value. Saturation occurs at a certain H′ij = 230.
[0039]
By the pixel value conversion by the conversion function Fn, the pixel value after processing does not exceed the threshold Th and is suppressed to gray whose luminance is lower than that of white, so that whiteout can be prevented.
[0040]
By the operation of the image processing apparatus 1 described above, the whiteout prevention process is performed independently of the sharpness correction, so that the whiteout can be prevented while ensuring the desired sharpness correction.
[0041]
Second Embodiment
<Configuration of main part of image processing apparatus>
The configuration of the image processing apparatus 1A according to the second embodiment of the present invention is similar to the configuration of the image processing apparatus 1 described above, but a program for performing an image processing operation described later is an overall control shown in FIG. It is stored in the memory 232 of the unit 23A.
[0042]
<Operation of Image Processing Apparatus 1A>
FIG. 5 is a flowchart showing an image processing operation in the image processing apparatus 1A. This operation is to perform sharpness correction by Laplacian for an image composed of pixel arrays, and is automatically executed by the CPU 231 of the control unit 23A.
[0043]
Further, the pixel value of each pixel on which the main image processing is performed has a range of 8 bits, that is, a range from the lower limit value 0 to the upper limit value 255, as in the first embodiment.
[0044]
In step S11, the same operation as step S1 shown in the flowchart of FIG. 3 is performed.
[0045]
In step S12, each pixel (pixel group) forming the image is converted by Laplacian ² . Specifically, if the pixel value in the pixel of the i-th row and j-th column of the pixel array forming the image is Kij, C is the gain coefficient for calculating the enhancement amount, and Hij is the processed pixel value, the following equation 2 is obtained. The operation shown is performed.
[0046]
[Equation 2]
Hij = Kij-C · ∇ ² Kij
Note that the Laplacian の^{2 in the} above equation is expressed by a second order differential, that is, ∂ ² / ∂x ² + ∂ ² / ∂y ² .
[0047]
Steps S13 to S18 perform the same operations as steps S3 to S8 shown in the flowchart of FIG.
[0048]
By the above-described operation of the image processing apparatus 1A, the whiteout prevention process is performed independently of the sharpness correction in the same manner as the image processing apparatus 1 of the first embodiment. Therefore, whiteout is prevented while ensuring the desired sharpness correction. it can.
[0049]
<Third Embodiment>
<Configuration of main part of image processing apparatus>
The configuration of the image processing apparatus 1B according to the third embodiment of the present invention is similar to the configuration of the image processing apparatus 1 described above, but a program for performing an image processing operation described later is an overall control shown in FIG. It is stored in the memory 232 of the unit 23B.
[0050]
<Operation of Image Processing Device 1B>
FIG. 6 is a flowchart showing an image processing operation in the image processing apparatus 1B. This operation is performed by extracting an edge region corresponding to a predetermined pixel group from an image composed of a pixel array and performing sharpness correction only on the edge region, and is automatically executed by the CPU 231 of the control unit 23B. Is done.
[0051]
Further, the pixel value of each pixel on which the main image processing is performed has a range of 8 bits, that is, a range from the lower limit value 0 to the upper limit value 255, as in the first embodiment.
[0052]
In step S21, the same operation as step S1 shown in the flowchart of FIG. 3 is performed.
[0053]
In step S22, all the pixels of the image are converted by primary differentiation. Specifically, when the pixel value in the pixel in the i-th row and j-th column of the pixel array forming the image is Kij and Eij is the primary differential amount, the following calculation is performed.
[0054]
[Equation 3]
Eij = grad Kij
Here, the primary differential grad is expressed as ∂ / ∂x + ∂ / ∂y in the case of differentiation in a 45-degree oblique direction.
[0055]
In step S23, it is determined whether the absolute value of the primary differential amount Eij is greater than or equal to a threshold value Th1. In other words, it is determined whether the image is the edge region in the processing target image. If Eij is greater than or equal to the threshold value Th1, the process proceeds to step S24. If Eij is smaller than the threshold value Th1, the process proceeds to step S31.
[0056]
In steps S24 to S30, operations similar to those in steps S12 to S18 shown in the flowchart of FIG. 3 are performed.
[0057]
By the operation of the image processing apparatus 1B described above, it is possible to prevent overexposure while ensuring desired sharpness correction, and it is possible to perform sharpness correction particularly targeting only the edge region.
[0058]
For the first-order differential filter for edge extraction, it is not essential to use the grad, and the Sobel shown in FIG. 7 or Previt shown in FIG. 8 may be used. 7 (a) and 8 (a) show a matrix in the case of processing in the horizontal direction, and FIGS. 7 (b) and 8 (b) show a case of processing in the vertical direction. A matrix is shown.
[0059]
<Fourth embodiment>
<Configuration of main part of image processing apparatus>
The configuration of the image processing apparatus 1C according to the fourth embodiment of the present invention is similar to the configuration of the image processing apparatus 1 described above, but a program for performing an image processing operation described later is an overall control shown in FIG. It is stored in the memory 232 of the unit 23C.
[0060]
<Operation of Image Processing Device 1C>
FIG. 9 is a flowchart showing an image processing operation in the image processing apparatus 1C. This operation differs from the operations of the above-described embodiments in that an operation for determining a threshold Thd is performed based on information on the entire image. The image processing operation in the image processing apparatus 1C is automatically executed by the CPU 231 of the control unit 23C.
[0061]
It should be noted that the pixel value of each pixel on which the image processing is performed has a range of 8 bits, that is, a lower limit value 0 to an upper limit value 255, as in the first embodiment.
[0062]
In steps S41 and S42, operations similar to those in steps S11 and S12 shown in the flowchart of FIG. 5 are performed.
[0063]
In step S43, a histogram is created as shown in FIG. 10 for the processed pixel value Hij converted in step S42. The horizontal axis in FIG. 10 indicates the pixel value Hij, and the vertical axis indicates the number of pixels n.
[0064]
In step S44, based on the histogram shown in FIG. 10, the number of pixels in the section HR exceeding the threshold value Thd in the vicinity of the upper limit value 255 of the range (see the parallel hatched portion) is, for example, A threshold value Thd is obtained such that the ratio is 3%.
[0065]
As a result, the threshold value Thd can be variably set according to the statistical information of the image, so that it is possible not to perform a fixed process but to perform a whiteout prevention process reflecting the information of the entire image.
[0066]
In steps S45 to S50, operations similar to those in steps S13 to S18 shown in the flowchart of FIG. 5 are performed.
[0067]
By the operation of the image processing apparatus 1C described above, the threshold value Thd is determined in consideration of the information of the entire image, so that it is possible to prevent whiteout more appropriately.
[0068]
<Modification>
In each of the above embodiments, image processing is performed on a color image, but image processing may be performed on a monochrome image. Specifically, in the first embodiment, the operation in step S1 and the operation in step S8 in the flowchart shown in FIG. 3 can be omitted. The same applies to the second to fourth embodiments.
[0069]
In each of the above embodiments, it is not essential to convert the RGB signal into an HSL signal, and the RGB signal may be converted into a Lab signal or a Luv signal having luminance or brightness information.
[0070]
For the whiteout prevention conversion in each of the above embodiments, the pixel value Hij may be converted by the conversion function Gn shown in FIG. This function Gn is a point Q (205, 205) where the linear functions G1 and G2 are connected. The linear function G2 is not a function parallel to the horizontal axis as in the function F2 shown in FIG. 4, and has a slope such that H′ij = Th (230) when Hij = 255. In this case, when the pixel value after image processing belongs to the end region from the first intermediate value 205 to the upper limit value 255 of the range, the pixel value is converted into the pixel value in the section SR according to the function G2. As a result, the same effects as in the above embodiments can be exhibited, and the change in the conversion characteristics of the pixel values near the connection point Q becomes relatively smooth.
[0071]
Further, the function related to the whiteout prevention conversion is not necessarily a combination of linear functions, and may include a nonlinear function such as a quadratic function.
[0072]
As for the threshold value Th in the first embodiment, the threshold value Th in step S5 and the threshold value Th in step S6 shown in the flowchart of FIG. 3 may be different values. As a result, conversion with a higher degree of freedom for preventing whiteout can be performed.
[0073]
Each of the above embodiments can be applied not only to a positive image but also to a negative image. Here, “out-of-white” in the negative image means that the pixel value is near the lower limit value 0 of the range.
[0074]
The present invention is not limited to sharpness correction, and can be applied to all image processing in which the pixel value after correction processing reaches the limit value of the range of pixel values.
[0075]
【The invention's effect】
As described above, according to claims 1 to an invention of claim 15, while ensuring the desired image processing can prevent image degradation such as whiteout.
[0076]
Particularly, in the inventions of claims 2 and 9 , since the first intermediate value is set to a fixed value, image quality deterioration such as overexposure can be easily prevented.
[0077]
In the inventions of claims 3 and 10 , since the first intermediate value is determined based on the statistical information relating to the second signal value in the predetermined pixel group, the information on the entire predetermined pixel group is reflected. Therefore, it is possible to appropriately prevent image quality deterioration such as whiteout.
[0078]
In the inventions of claims 4 and 11 , since the statistical information is a ratio between the number of pixels having the second signal value near the limit value of 1 and the number of pixels in the predetermined pixel group, Image quality deterioration such as overexposure can be prevented more appropriately.
[0079]
In the inventions according to claims 6 and 13 , since the end region is set at the end on the high brightness side when reproducing the image which is each frame of the moving image, the white area is effectively whitened with respect to the moving image in which whiteout is conspicuous. Jump prevention is possible.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a main configuration of an image processing apparatus 1 according to a first embodiment of the present invention.
FIG. 2 is a diagram showing functional blocks of the image processing apparatus 1;
FIG. 3 is a flowchart showing an image processing operation in the image processing apparatus 1;
4 is a diagram for explaining an image processing operation in the image processing apparatus 1. FIG.
FIG. 5 is a flowchart showing an image processing operation in the moving image processing apparatus 1A.
FIG. 6 is a flowchart showing an image processing operation in the moving image processing apparatus 1B.
FIG. 7 is a diagram illustrating a first-order differential filter for edge extraction.
FIG. 8 is a diagram illustrating a first-order differential filter for edge extraction.
FIG. 9 is a flowchart showing an image processing operation in the moving image processing apparatus 1C.
FIG. 10 is a diagram for explaining an image processing operation in the image processing apparatus 1C.
FIG. 11 is a diagram for explaining an image processing operation according to a modification.
[Explanation of symbols]
1, 1A, 1B, 1C Image processing device 3 Operation unit 4 Monitor 9 Recording medium 23, 23A, 23B, 23C Control unit Fn, Gn Conversion function

Claims (15)

An image processing apparatus that performs image processing on an image composed of a plurality of pixels having a first signal value with a defined range,
(a) processing means for performing image processing for a given pixel group according to the image, performs image processing for generating the second signal value based on the first signal value,
(b) setting means for setting a section from the first intermediate value to one limit value in the range as an end region;
(c) determining means for determining whether or not the first signal value belongs to the end region, and whether or not the second signal value belongs to the end region;
(d) First output control means for outputting the first signal value when the determination means determines that the first signal value belongs to the end region for the predetermined pixel group. When,
(e) For the predetermined pixel group, when the determination unit determines that the first signal value does not belong to the end region and the second signal value belongs to the end region. includes a second output control means for outputting a signal value which does not exceed a second intermediate value which is set apart from the limit value of the one,
(f) For the predetermined pixel group, when the determination means determines that neither the first signal value nor the second signal value belongs to the end region, the second signal Third output control means for outputting a value;
An image processing apparatus comprising: The image processing apparatus according to claim 1.
The image processing apparatus according to claim 1, wherein the first intermediate value is set to a fixed value. The image processing apparatus according to claim 1 or 2,
(g) determining means for determining the first intermediate value based on statistical information relating to the second signal value in the predetermined pixel group;
An image processing apparatus further comprising: The image processing apparatus according to claim 3.
The statistical information is obtained based on a ratio between the number of pixels in which the second signal value is in the vicinity of the one limit value and the total number of pixels in the predetermined pixel group. . The image processing apparatus according to any one of claims 1 to 4,
The image processing apparatus, wherein the first intermediate value and the second intermediate value are equal. The image processing apparatus according to any one of claims 1 to 5,
The image is each frame of the video,
The image processing apparatus according to claim 1, wherein the end region is set at an end portion on the high brightness side during reproduction of the image. The image processing apparatus according to any one of claims 1 to 6,
The image processing apparatus characterized in that the image processing performed by the processing means is processing related to sharpness correction. An image processing method that performs image processing on an image that is executed by an image processing apparatus and includes a plurality of pixels having a first signal value with a defined range,
(a) A processing step of performing image processing on a predetermined pixel group related to the image and performing image processing to generate a second signal value based on the first signal value;
(b) A setting step of setting a section from the first intermediate value to one limit value of the range as an end region;
(c) A determination step of determining whether or not the first signal value belongs to the end region, and whether or not the second signal value belongs to the end region;
(d) A first output control step for outputting the first signal value when the determination step determines that the first signal value belongs to the end region for the predetermined pixel group;
(e) For the predetermined pixel group, in the determination step, when it is determined that the first signal value does not belong to the end region and the second signal value belongs to the end region, A second output control step for outputting a signal value that does not exceed a second intermediate value set apart from the one limit value;
(f) For the predetermined pixel group, when it is determined in the determination step that the first signal value and the second signal value do not belong to the end region, the second signal value is output. A third output control step to
An image processing method comprising: The image processing method according to claim 8.
The image processing method according to claim 1, wherein the first intermediate value is set to a fixed value. The image processing method according to claim 8 or 9,
(g) A determining step of determining the first intermediate value based on statistical information relating to the second signal value in the predetermined pixel group;
An image processing method further comprising: The image processing method according to claim 10,
The statistical information is obtained based on a ratio between the number of pixels in which the second signal value is close to the one limit value and the total number of pixels in the predetermined pixel group. . The image processing method according to any one of claims 8 to 11,
The image processing method, wherein the first intermediate value and the second intermediate value are equal. The image processing method according to any one of claims 8 to 12,
The image is each frame of the video,
The image processing method according to claim 1, wherein the end region is set at an end portion on the high brightness side during reproduction of the image. The image processing method according to any one of claims 8 to 13,
An image processing method, wherein the image processing performed in the processing step is processing related to sharpness correction. 15. A computer-readable recording medium on which a program for causing a computer built in the image processing apparatus to execute the image processing method according to claim 8 is recorded.

Images