JP2007094917A - Image processing device, image processing method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct luminance unevenness with consideration given not only to the characteristics of a lens and an imaging sensor in an imaging device, but also to the characteristics and content of an object image. <P>SOLUTION: This image processing device is provided with a projection system, including a lens optical system 12 photographing the objective image for acquiring an image signal and a CCD 13; a control part 22 determining the type of image from the image signal acquired by the projection system, setting the correction coefficient for luminance unevenness, according to the determination result, and making a JPEG circuit 28 correct the luminance value of the image signal acquired by the projection system by using the correction coefficient on a pixel basis; and a built-in memory 29 or a memory card 30 storing the image signal with luminance correction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, a pixel processing method, and a program suitable for a digital camera, for example.

  Conventionally, in an imaging apparatus that performs imaging using a solid-state imaging device such as a CCD, luminance unevenness may occur in a captured image due to the influence of an optical system such as a CCD or a lens. There was a need for technology to remove it.

Therefore, there is a technique for storing a correction value calculated in consideration of the distance from the center of the lens when a reference image is captured in advance, and correcting luminance unevenness of the captured image based on the correction value. It was thought. (For example, Patent Document 1)
JP 2004-200908 A

  The technique described in the above-mentioned patent document applies the correction value calculated based on the reference image uniformly, and the content of the subject image to be photographed, such as black and white characters with very high contrast, etc. It seems that the degree to which it is affected by uneven brightness depends on whether it is a document image consisting of or an image with little change in which a uniform color is extended throughout. Is not considered at all.

  The present invention has been made in view of the above circumstances, and the object of the present invention is not only the characteristics of the lens and the image sensor in the imaging apparatus, but also the luminance and brightness of the target image. An object is to provide an image processing apparatus, a pixel processing method, and a program capable of performing unevenness correction.

  According to the first aspect of the present invention, the input means for inputting the image signal, the determination means for determining the type of the image from the image signal obtained by the input means, and the luminance unevenness according to the determination result obtained by the determination means Setting means for setting a correction coefficient, luminance correction means for correcting the luminance value of the image signal obtained by the input means by a correction coefficient set by the setting means in pixel units, and luminance correction after passing through the luminance correction means Output means for outputting an image signal.

  According to the first aspect of the present invention, it is possible to perform luminance unevenness correction in consideration of the type of target image.

  Hereinafter, an embodiment when the present invention is applied to a digital camera will be described with reference to the drawings.

  FIG. 1 shows a functional configuration of an electronic circuit of the digital camera 10. In the figure, in the monitoring state in the photographing mode, the positions of some lenses in the lens optical system 12 constituting the photographing lens, specifically the zoom lens and the focus lens, are appropriately set by driving the motor (M) 11. Moved. A CCD 13, which is a solid-state image sensor, is disposed via an unillustrated mechanical shutter at an imaging position behind the photographing optical axis of the lens optical system 12.

  The CCD 13 is scanned and driven by a timing generator (TG) 14 and a CCD driver 15, and outputs a photoelectric conversion output corresponding to a light image formed at fixed intervals for one screen.

  The photoelectric conversion output is appropriately gain-adjusted for each primary color component of RGB in the state of an analog value signal, sampled and held by a sample hold circuit (S / H) 16, and digital data by an A / D converter 17. The color process circuit 18 performs color process processing including pixel interpolation processing and gamma correction processing in the color process circuit 18 to generate a digital luminance signal Y and color difference signals Cb, Cr, and a DMA (Direct Memory Access) controller 19. Is output.

  The DMA controller 19 once uses the luminance signal Y and the color difference signals Cb and Cr output from the color process circuit 18 by using the composite synchronization signal, the memory write enable signal, and the clock signal from the color process circuit 18 once. And the DMA transfer to the DRAM 21 used as a buffer memory through the DRAM interface (I / F) 20.

  The control unit 22 includes a CPU, a non-volatile memory in which an operation program including processing for correcting luminance unevenness in a shooting mode, which will be described later, is fixedly stored, a work memory, and the like. The control operation of the entire digital camera 10 is performed. After the DMA transfer of the luminance and color difference signals to the DRAM 21 is completed, the luminance and color difference signals are read from the DRAM 21 via the DRAM interface 20 and written to the VRAM 24 via the VRAM controller 23.

  The digital video encoder 25 periodically reads the luminance and color difference signals from the VRAM 24 via the VRAM controller 23, generates a video signal based on these data, and outputs the video signal to the display unit 26.

  The display unit 26 functions as a monitor display unit (electronic finder) in the shooting mode, and performs display based on the video signal from the digital video encoder 25, and captures from the digital video encoder 25 at that time. An image based on the image information is displayed in real time.

  In this way, a key input unit 27 (to be described later) is configured at a timing at which still image shooting is desired in a so-called through image display state in which an image at that time is displayed in real time on the display unit 26 as a monitor image. When a shutter key that is an element is operated, a trigger signal is generated.

  In response to the trigger signal, the control unit 42 cancels the DMA transfer of the luminance and color difference signals for one screen currently captured from the CCD 13 to the DRAM 21 and sets an aperture value according to the appropriate exposure condition again. Further, the mechanical shutter (not shown) and the CCD 13 are driven at the set shutter speed to obtain one-screen start-up and color difference signals and transfer them to the DRAM 21. Then, this path is stopped, and the state is changed to the storage and storage state.

  In this storage and storage state, the control unit 22 outputs the luminance and color difference signals for one frame written in the DRAM 21 through the DRAM interface 20 for each of Y, Cb, and Cr components of 8 pixels × 8 pixels horizontally. Are written in a unit called a basic block of JPEG (Joint Photographic Coding Experts Group) circuit 28, which is an image processing engine. Data compression is performed by a process such as Huffman coding.

  Then, the obtained code data is read out from the JPEG circuit 28 as a data file of one image, and written into the built-in memory 29 which is a storage medium of the digital camera 10 or a memory card 30 which is detachably attached to the digital camera 10. .

  Then, along with the compression processing of the luminance and color difference signals for one frame and the completion of writing of all the compressed data to the built-in memory 29 or the memory card 30, the control unit 22 activates the path from the CCD 13 to the DRAM 21 again.

  Here, it is assumed that the internal memory 29 and the memory card 30 write and read various data including still image data with priority given to the memory card 30. That is, when the memory card 30 is removed and does not exist, writing / reading to / from the built-in memory 29 is performed, while when the memory card 30 is mounted, data writing / reading is performed to / from the memory card 30. To do.

  In addition, a key input unit 27, an audio processing unit 31, and a strobe driving unit 32 are connected to the control unit 22.

  The key input unit 27 includes a power key, a tele / wide key, a shooting mode key, a playback mode key, a ring key, a set key, a menu key, a macro key, a strobe key, and the like in addition to the shutter key described above. Signals accompanying these key operations are sent directly to the control unit 22.

  The sound processing unit 31 includes a sound source circuit such as a PCM sound source. When recording sound, the sound processing unit 31 digitizes the sound signal input from the microphone unit (MIC) 33 provided on the front surface of the housing of the digital camera 10 to obtain predetermined sound data. In accordance with a file format, for example, MP3 (MPEG-1 audio layer 3) standard, the data is compressed to create an audio data file and sent to the internal memory 29 or the memory card 30. On the other hand, when reproducing the audio, the internal memory 29 or the memory card The audio data file sent from 30 is uncompressed and converted into an analog signal, and the speaker unit (SP) 34 provided on the back of the casing of the digital camera 10 is driven to emit a loud sound.

  The strobe driving unit 32 charges a large-capacitance capacitor for strobe (not shown) at the time of still image shooting, and then, based on control from the control unit 22, a strobe light emitting unit 35 provided on the upper front of the casing of the digital camera 10. The flash drive.

  However, when shooting of a moving image instead of a still image is selected, the above-described still image data is acquired and compressed by the JPEG circuit 28 when the first shutter key is operated, and the built-in memory 29 or a series of operations of storing in the memory card 30 is started as a continuous execution at an appropriate frame rate, for example, 30 [frame / second], and the shutter key is operated for the second time, or a predetermined operation is performed. When a time limit, for example, 30 seconds elapses, the series of still image data files are collectively set as a motion JPEG data file (AVI file).

  In the playback mode, the control unit 22 selectively reads out the image data stored in the built-in memory 29 or the memory card 30, and is compressed by a procedure completely opposite to the procedure of data compression in the shooting mode by the JPEG circuit 28. The decompressed image data is decompressed, and the decompressed image data is held in the DRAM 21 via the DRAM interface 20, and then the content held in the DRAM 21 is stored in the VRAM 24 via the VRAM controller 23. Is read out to generate a video signal which is reproduced and output by the display unit 26.

  If the selected image data is not a still image but a moving image, playback of the individual still image data constituting the selected moving image file is executed continuously in time, and playback of the last still image data is finished. At that time, the image is reproduced and displayed using only the still image data located at the head until the next reproduction instruction is given.

Next, the operation of the above embodiment will be described.
In this digital camera 10 as well, other shutter cameras have a two-step operation stroke, and the first step is an operation up to about half of the full stroke, generally called half-press. The automatic focusing (AF) process and the automatic exposure (AE) process are executed in the operation state to lock the respective processing values, and then the second stage is a full stroke operation, generally referred to as a full press. In this state, it is assumed that a shooting operation based on the operation logic of executing the main shooting with the AF value and the AE value is executed.

  In the following shooting modes, the operation in a state where both “brightness unevenness correction function” and “(rectangular) contour extraction function” are set to “present” by the user mode setting is shown. The operation control is executed by the control unit 22 based on an operation program stored in an internal nonvolatile memory.

  FIG. 2 shows the contents of processing executed when still image shooting is performed in the shooting mode. At the beginning, the processing is performed at a predetermined frame rate, for example, 30 [frames / second]. A simple AF process and AE process are executed, and the CCD 13 is continuously driven at a high shutter speed in consideration of the frame rate, whereby the state of the through image display in which the content captured by the CCD 13 is displayed on the display unit 26 is displayed. While maintaining (step M01), it is determined whether or not the shutter key of the key input unit 27 has been half-pressed (step M02). stand by.

  Thus, when the shutter key is half-pressed, this is determined in step M02, and AF processing is executed at a focal length corresponding to the zoom lens position of the lens optical system 12 at that time to lock the focus position. (Step M03), an appropriate aperture and shutter speed are obtained by AE processing and locked (step M04).

  With the AF value and the AE value locked, it is repeatedly determined whether the shutter key is further fully pressed (step M05) and whether it is still half-pressed (step M06). It waits until the shutter key is fully pressed or the half-pressed state is released while locking each state of the value and the AE value.

  Here, when the half-press operation of the shutter key is released, this is determined in step M06, it is assumed that the photographing has not been completed, and the process returns to step M01 again.

  When the shutter key is fully pressed from the state in which the AF value and the AE value are locked, this is determined in step M06, and a still image is shot with the AF value and the AE value being locked. (Step M07), image data is obtained and stored in the DRAM 21 (Step M08).

Then, the type of the image is determined based on the content of the image data held in the DRAM 21 (step M09).
FIG. 3 shows a subroutine of detailed processing contents relating to the discrimination of the type of image, and at the beginning, a process of extracting a (rectangular) contour from the photographed image is executed (step S01).

  This is because the “contour extraction function” is selected as “present” by the user's mode setting as described above, and when a rectangular region occupying a predetermined area or more in the captured image including the center of the image is extracted, Next, a total SCD value of the amount of change of the color difference signal component of the image signal within the extracted rectangular outline is calculated (step S02).

  Then, it is determined whether or not the calculated total SCD value of the change amount of the color difference signal component exceeds a preset first threshold value (step S03).

  Here, when it is determined that the total amount of change of the color difference signal components exceeds a preset first threshold value, the image in the contour is a colorful image in which various color patterns are mixed. 3 is recognized and the recognition result is held (step S04). Then, the subroutine for determining the image type in FIG. 3 is terminated, and the process returns to the main routine in FIG.

  FIG. 4 exemplifies a colorful photographed image IM1, and shows a state in which a pamphlet for displaying a colorful image is placed on a table with an oblique stripe pattern prepared for contour extraction. Here, since various colors are used for the background photographic part and the character part, the amount of change in the color difference signal component is large, and it can be easily recognized that the image is colorful.

  If it is determined in step S03 that the total SCD value of the change amounts of the color difference signal components is equal to or less than a preset threshold value, then the second SC in which the total sum SC value of the color difference signal components is set in advance. It is determined whether or not the threshold value is exceeded (step S05).

  If it is determined that the total SC value of the color difference signal components is equal to or smaller than a second threshold value set in advance, the image in the contour is recognized as a monochrome image with poor color, and the recognition is performed. After holding the result (step S06), the subroutine for determining the image type in FIG. 3 is terminated, and the process returns to the main routine in FIG.

  FIG. 5 exemplifies a black-and-white photographed image IM2, and a document in which characters, numbers, ruled lines, etc. are printed in black on a blank sheet is placed on a table with an oblique stripe pattern prepared for contour extraction. The state that has been done. Here, since the components of the color difference signal are hardly calculated in the contour, it can be easily recognized that the image is a monochrome image.

  Further, when it is determined in step S05 that the total SC value of the color difference signal components exceeds a preset second threshold value, the image in the contour is recognized as a single color image, After holding the recognition result (step S07), the subroutine for determining the image type in FIG. 3 is terminated, and the process returns to the main routine in FIG.

  In the above example, the total SCD value of the change amount of the chrominance signal component and the total SC value of the chrominance signal component are used to distinguish the images, but other methods that refer to the contrast of the image or the like may be used. It doesn't matter.

  FIG. 6 exemplifies a single-color photographed image IM3, and shows a state in which a solid, single-color file-like object is placed on a table with an oblique stripe pattern prepared for contour extraction. . Here, although the sum SC value of the color difference signal components is a certain amount or more, there is almost no sum of the amount of change of the color difference signal components, so that it can be easily recognized that the image is a single color image.

  If “None” is selected as the “contour extraction function” by the user mode setting, the contour extraction processing in step S01 is not performed, and the processing in step S02 and subsequent steps is also performed on the entire captured image. Therefore, depending on the case, there is a high possibility that the type of image to be captured is erroneously determined.

  Therefore, in the main routine of FIG. 2, after the processing of the subroutine for determining the image type in step M09, the fineness of the image, that is, the resolution is determined by the number of pixels of the image size set at that time, The determination result is held (step M10).

  Next, based on the image type determination result in step M09 and the image resolution determination result in step M10, a correction coefficient A for correcting luminance unevenness is determined (step M11).

Here, the correction coefficient A is a multiplier,
"Black and white image> Single color image> Colorful image"
In addition to the case of a monochrome image and a colorful image, the resolution is high according to the determination result of the above resolution. As such, it may be appropriately increased so as to have a larger value.

  A colorful image may have a completely different hue from the original image if too much correction is applied, or the pattern may be crushed and become unnatural. May be set relatively low.

  Similarly to a colorful image, it is not good for a monochrome image to change its hue too much, but a correction coefficient A larger than a colorful image may be set as long as there is no pattern.

  In black and white images, the colors used are only white and black, and there is no concern that the hue or pattern will change, so it is better to increase the correction coefficient A within a range where black lines and characters do not disappear. Since a result is obtained, a larger correction coefficient A may be set.

  Thereafter, the JPEG circuit 28 reads the photographed image to be corrected for luminance unevenness and divides it into a plurality of blocks, calculates the pixel with the maximum luminance value for each block (step M12), and sets the maximum luminance value for all the paths. An average value is calculated (step M13).

  FIG. 7 illustrates block division of the photographed image. Here, the image data IM obtained by photographing is divided in units of 8 vertical pixels × 8 horizontal pixels, which are called basic blocks in JPEG and MPEG. To do.

The luminance unevenness correction process is executed in a state where the maximum luminance value is calculated for each of the divided blocks and the average value of the maximum luminance values in all the roads is calculated (step M14). That is, each block is Bxy, the luminance of each pixel in the block is Kab, the maximum luminance is Kmax, and the average value of the maximum luminance values in all blocks is Kave.
Bxy (Kab) '= Bxy (Kab)
−A × [Bxy (Kmax) −Kave]
… (1)
(Bxy (Kmax): Maximum brightness of each block,
Kave: Average value of maximum luminance values in all blocks,
Bxy (Kab): luminance before correction of each pixel of each block,
Bxy (Kab) ′: luminance after correction of each pixel of each block,
A: Correction coefficient. )
A process of correcting the luminance value of each pixel using the following equation (1) and rewriting the corrected luminance value is executed in units of blocks.

  When the photographed image is a single color image as shown in FIG. 6 due to the brightness unevenness correction process, adjustment is desired so that the brightness level does not increase so much and the brightness unevenness is eliminated. Luminance correction processing with a small correction coefficient A is executed.

  On the other hand, when the photographed image is a black and white image as shown in FIG. 5 above, it is desired to finely express a fine line having a very high spatial frequency, but on the other hand, it is a stain on the document expressed in a region having a low spatial frequency. Since it is desirable to process the image so as not to be conspicuous, the luminance correction processing with a larger correction coefficient A is executed as compared with the case of the monochromatic image.

  Further, when the photographed image is a colorful image as shown in FIG. 4 above, it is preferable to clearly express the level of the brightness, so that the image is sharper and therefore larger than the case of the black and white image. A luminance correction process using the correction coefficient A is executed.

  In addition, when the captured image is a black and white image or a colorful image, it is better to clearly express the brightness level in a fine (= high resolution) image according to the resolution result determined in step M10. In order to obtain a preferable image, the correction coefficient is further increased as the resolution increases.

  However, after the luminance unevenness correction process is performed on the entire captured image data, the JPEG circuit 28 continues to compress the data amount to convert the image data into a data file (step M15), and the filed image data is stored in the built-in memory 29. Alternatively, the data is recorded in the memory card 30 (step M16), and the series of processing from shooting to recording is completed as described above, and the processing returns to step M01 to prepare for the next shooting again.

  In this way, after determining the type of the target image and determining the correction coefficient according to the determination result to correct the brightness unevenness, the brightness unevenness correction is performed without darkness. It is possible to always correct luminance unevenness at an appropriate level.

  In addition, when performing the above-described luminance unevenness correction calculation, luminance correction is performed by dividing adjacent pixels into blocks and correcting the luminance unevenness in units of blocks, instead of performing the entire image collectively. This process can be executed more efficiently.

  In this case, the block size of the JPEG circuit 28 is corrected by performing luminance unevenness correction processing based on a basic block of 8 vertical pixels × 8 horizontal pixels, which is a basic unit of image processing technology represented by JPEG and MPEG. It is highly compatible with other image processing steps to be executed in the above, and the application range can be further expanded.

  Furthermore, in addition to determining the type of image, the correction calculation is performed after adjusting the correction coefficient in consideration of the resolution of the image, so there is no sense of incongruity and more natural correction of luminance unevenness is performed. Can be made.

  Further, in the above-described embodiment, a rectangular outline is extracted from a captured image, and luminance unevenness is corrected for an image within the extracted rectangular outline.

  As a result, not only a general digital camera but also, for example, a document camera that projects and displays an image captured by connecting to a projector device, images a document document placed on a document table, and the like. As in the case of correcting the luminance unevenness of the image, the image range to be corrected for the luminance unevenness can be accurately extracted, and the luminance unevenness can be corrected with higher accuracy.

  Furthermore, if the captured image is an image that appears to be colorful as a whole because the amount of change in the color difference signal constituting the image signal is particularly large, the correction coefficient of the luminance unevenness correction calculation is set to a larger value. By determining, it is possible to obtain an image that is not noticeably uneven in brightness and that is sharp on the whole.

  In addition, the entire image is assumed to be monochromatic, especially when the amount of change in the color difference signal constituting the image signal is below a certain level and the absolute amount of the color difference signal exceeds a certain level. If the image is a non-uniform image, it is possible to obtain an image with a natural depiction by not correcting the luminance unevenness by reducing the correction coefficient and adding sharpness.

  Furthermore, the entire captured image is a monochrome document document or the like in which the change amount of the color difference signal constituting the image signal is not more than a certain degree and the absolute amount of the color difference signal is not more than a certain degree. In the case of an expected image, it is possible to obtain an image that is easier to read by correcting the luminance unevenness so that the thin lines are clearly expressed while the dirt on the document is attenuated.

  Although the above embodiment is applied to the digital camera 10 and has been described as taking an image with the CCD 13 which is a solid-state image pickup device as means for inputting an image, the solid-state image pickup device is a CCD or CMOS. Any of image sensors may be used.

  Further, the present embodiment has been described for a case where the present invention is applied to a digital camera, and image data is input by taking a picture, and after correcting luminance unevenness of the input image, the built-in memory 29 or the memory card However, the present invention is not limited to this, and for example, a projector device, a mobile phone with a camera function, and a memory card are attached, and the image data in the memory card is displayed on a large screen. Liquid crystal viewers to be displayed on LCD panels, PDAs (Personal Digital Assistants) with personal communication functions, personal computers regardless of notebook type / desktop type, portable music players that can handle image data, Other image data handling It can be applied to all devices.

  Further, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention in the implementation stage. In addition, the functions executed in the above-described embodiments may be combined as appropriate as possible. The above-described embodiment includes various stages, and various inventions can be extracted by an appropriate combination according to a plurality of disclosed structural requirements. For example, even if several constituent requirements are deleted from all the constituent requirements shown in the embodiment, if an effect is obtained, the configuration from which the constituent requirements are deleted can be extracted as an invention.

1 is a block diagram showing a functional circuit configuration of a digital camera according to an embodiment of the present invention. The flowchart which shows the processing content of the main routine at the time of the imaging | photography mode which concerns on the embodiment. 7 is a flowchart showing the processing contents of a subroutine related to image type discrimination in the shooting mode according to the embodiment. The figure which illustrates the picked-up image which concerns on the same embodiment. The figure which illustrates the picked-up image which concerns on the same embodiment. The figure which illustrates the picked-up image which concerns on the same embodiment. The figure for demonstrating the blocking of the image which concerns on the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Digital camera, 11 ... Motor (M), 12 ... Lens optical system, 13 ... CCD, 14 ... Timing generator (TG), 15 ... CCD driver, 16 ... Sample hold circuit (S / H), 17 ... A / D converter, 18 ... color process circuit, 19 ... DMA controller, 20 ... DRAM interface (I / F), 21 ... DRAM, 22 ... control unit, 23 ... VRAM controller, 24 ... VRAM, 25 ... digital video encoder, 26 ... Display unit, 27 ... Key input unit, 28 ... JPEG circuit, 29 ... Built-in memory, 30 ... Memory card, 31 ... Audio processing unit, 32 ... Strobe drive unit, 33 ... Microphone unit (MIC), 34 ... Speaker unit (SP), 35... Strobe light emitting unit.

Claims (10)

An input means for inputting an image signal;
Discriminating means for discriminating the type of image from the image signal obtained by the input means;
Setting means for setting a correction coefficient for luminance unevenness according to the determination result obtained by the determination means;
Luminance correction means for correcting the luminance value of the image signal obtained by the input means by a correction coefficient set by the setting means in units of pixels;
An image processing apparatus comprising: output means for outputting an image signal after brightness correction that has passed through the brightness correction means.   The luminance correction means divides the image signal into a plurality of blocks, and corrects the luminance value by further using the maximum luminance value of the pixel in each divided block and the average value of the maximum luminance value in all blocks. The image processing apparatus according to claim 1.   3. The image processing apparatus according to claim 2, wherein the block into which the image signal is divided has a basic block of 8 vertical pixels × 8 horizontal pixels as a unit.   The image processing apparatus according to claim 1, wherein the setting unit sets a correction coefficient for luminance unevenness according to the determination result obtained by the determination unit and the resolution of the image signal.   The image processing apparatus according to claim 1, wherein the determination unit performs a contour extraction process on the image signal obtained by the input unit, and determines a type of an image in the extracted contour. The discrimination means discriminates this when the change amount of the color difference signal constituting the image signal exceeds a certain degree,
The image processing apparatus according to claim 1, wherein the setting unit sets a correction coefficient prepared in advance according to the determination result. The discrimination means discriminates when the change amount of the color difference signal constituting the image signal is equal to or less than a certain degree and the absolute amount of the color difference signal exceeds a certain degree,
The image processing apparatus according to claim 1, wherein the setting unit sets a correction coefficient prepared in advance according to the determination result. The discrimination means discriminates this when the change amount of the color difference signal constituting the image signal is not more than a certain degree and the absolute amount of the color difference signal is not more than a certain degree,
The image processing apparatus according to claim 1, wherein the setting unit sets a correction coefficient prepared in advance according to the determination result. An input process for inputting an image signal;
A discrimination step for discriminating the type of image from the image signal obtained in this input step;
A setting step of setting a correction coefficient for luminance unevenness according to the determination result obtained in this determination step;
A luminance correction step of correcting the luminance value of the image signal obtained in the input step by the correction coefficient set in the setting step in units of pixels;
An image processing method comprising: an output step of outputting an image signal after luminance correction after the luminance correction step. An input step for inputting an image signal;
A determination step of determining the type of image from the image signal obtained in this input step;
A setting step for setting a correction coefficient for luminance unevenness according to the determination result obtained in this determination step;
A luminance correction step for correcting the luminance value of the image signal obtained in the input step by a correction coefficient set in the setting step in units of pixels;
A program for causing a computer to execute an output step of outputting an image signal after luminance correction after the luminance correction step.

Images