JP4258735B2 - Image processing method, apparatus, program, and printer - Google Patents

Description

  The present invention relates to an image processing method, apparatus, program, and printer, and more particularly to a technique for whitening a human face.

  Conventionally, in an amusement sticker printing machine that synthesizes and prints a photographed face image and a template image, the following two methods are adopted so that a photographic print having a brightness desired by the user can be output.

  (a) Have the user select the brightness before shooting, and shoot with shooting conditions (aperture value, shutter speed) corresponding to the selected brightness.

  (b) Allow the user to select the brightness after shooting and adjust the brightness by performing image processing (for example, changing the highlight portion of the tone curve to be convex upward).

  Conventionally, when a light and dark film image is exposed to a photosensitive material, so-called dodging is performed so that the highlight portion of the film image does not fly out and the shadow portion does not collapse black. An image processing method that can obtain the same effect as the above has been proposed (Patent Document 1).

The image processing method described in Patent Document 1 generates a blurred image from an original image, and based on the blurred image, darkens the brightness of the pixels of the original image corresponding to the pixels of the highlight portion of the blurred image. By obtaining a correction amount to increase the brightness of the pixels of the original image corresponding to the shadow portion of the blurred image, and adding this correction amount to the original image, while maintaining the sharpness of the image, whiteout or blackout A high-quality processed image with no image is obtained.
JP-A-9-130609

  In a conventional amusement sticker printing machine, when obtaining a photo print of the user's preferred brightness, if the brightness is adjusted by the method (b) above, the slope of the tone curve in the highlight area will be reduced, so that the processed image There is a problem that the gradation change in the highlight portion (for example, the face) in the inside becomes small and whitening occurs, but the face image lacks stereoscopic effect.

  On the other hand, the image processing method described in Patent Document 1 is an image process that eliminates whiteout in a highlight portion and blackout in a shadow portion in an image, and is not image processing that makes whitening.

  The present invention has been made in view of such circumstances, and can perform a process (whitening process) to brighten the highlight portion in the image without losing the stereoscopic effect of the highlight portion in the image. An object is to provide an image processing method, an apparatus, a program, and a printer.

In order to achieve the above object, an image processing method according to claim 1 is configured to generate a first blurred image from a digital original image, and based on brightness of each pixel of the first blurred image. A process for brightening only the pixels of only the highlight portion of the first blurred image, and gradation conversion so that the pixels of only the highlight portion of the first blurred image are convex upward according to the brightness adding a step to produce a difference image by subtracting the first blurred image from the original image, and the difference image and the second blurred image to generate a second blurred image by performing a process of And a step of generating a whitened image.

  In the image processing method according to the first aspect, first, a first blurred image is generated from a digital original image. For example, the original image is converted into a blurred image through a predetermined digital filter such as an IIR (Infinite Impulse Response) type filter or FIR (Finite Impulse Response) type filter. Next, using the first blurred image, a second blurred image in which only the highlight portion of the first blurred image is brightened is generated. On the other hand, a difference image is generated by subtracting the first blurred image from the original image. By adding the difference image and the second blurred image, an image having a whitening effect is generated. The difference image includes, for example, a high-frequency component that bears detail information such as the unevenness of the face. Therefore, the processed image to which the difference image is added loses the stereoscopic effect of the highlight portion (face). It will never be.

The image processing method according to claim 2 includes a step of generating a blurred image from a digital original image, and an original image corresponding to pixels of only a highlight portion of the blurred image based on brightness of each pixel of the blurred image. A correction amount for making the brightness of the pixel more bright, the step of obtaining a correction amount that protrudes upward according to the brightness of the pixel of the highlight portion, and the correction amount obtained for the original image And a step of generating an image subjected to whitening by adding.

  The invention according to claim 2 differs from the invention according to claim 1 in processing steps, but the image after the whitening process is the same.

  The image processing method according to claim 1 or 2, wherein the original image is a color image composed of R, G, and B color images, and the whitening process is performed for each color image. It is a feature.

  The image processing method according to claim 1 or 2, wherein the original image is a color image composed of a luminance image and a color difference image, and the whitening process is performed only on the luminance image. It is characterized by.

The image processing apparatus according to claim 5 includes: a first blurred image generating unit configured to generate a first blurred image from a digital original image; and the first blurred image based on brightness of each pixel of the blurred image. A process of making the pixels of only the highlight portion of the first image brighter, and performing a gradation conversion so that the pixels of only the highlight portion of the first blurred image are convex upward according to the brightness. Second blur image generating means for generating a second blurred image, subtracting means for generating a difference image obtained by subtracting the first blurred image from the original image, the second blurred image, And adding means for adding the difference image to generate a whitened image.

The image processing apparatus according to claim 6 corresponds to a blur image generation unit that generates a blur image from a digital original image, and only pixels in the highlight portion of the blur image based on the brightness of each pixel of the blur image. Correction amount generating means for obtaining a correction amount for making the brightness of the pixel of the original image brighter , which is convex upward according to the brightness of the pixel of the highlight portion, and the original image And adding means for adding the obtained correction amount to generate a whitened image.

  According to a seventh aspect of the present invention, in the image processing apparatus according to the fifth aspect, the first blurred image generation unit is configured to reduce the blur for the low-luminance pixels of the original image. It is characterized by generating a blurred image. For example, the pupil region may become brighter than before blur due to the blur effect, and may shift to a brightness that is whitened. In this case, whitening processing is also performed on the pupil region, and the pupil becomes brighter, resulting in an adverse effect that the sharpness is lost and the image is not clear. In order to prevent this, in the invention described in claim 7, the blur effect in a dark region is lowered.

  The image processing apparatus according to claim 6, wherein the blur image generation unit generates the blur image so that blur is reduced with respect to a low-luminance pixel of the original image. It is characterized by.

  The image processing apparatus according to claim 5 or 6, wherein the original image is a color image composed of R, G, B color images, and the whitening process is performed for each color image. It is a feature.

  The image processing apparatus according to claim 5 or 6, wherein the original image is a color image including a luminance image and a color difference image, and the whitening process is performed only on the luminance image. It is characterized by.

  According to an eleventh aspect of the present invention, in the image processing apparatus according to the fifth aspect, the second blurred image generation unit preliminarily corresponds to the brightness information of the input pixel in the highlight portion of the first blurred image. A lookup table for storing brightness information for making the pixels brighter, and reading the corresponding brightness information from the lookup table each time the brightness information of each pixel of the first blurred image is input And outputting as the second blurred image. Note that a plurality of lookup tables may be provided according to the degree of whitening processing, and an appropriately selected lookup table may be used.

  The image processing apparatus according to claim 6, wherein the correction amount generation unit corresponds to an original image corresponding to a pixel in a highlight portion of the blurred image corresponding to brightness information of the input pixel in advance. A look-up table that stores a correction amount for making the brightness of the pixels brighter, and reads the corresponding correction amount from the look-up table each time the brightness information of each pixel of the blurred image is input. It is characterized by output.

  The image processing device according to claim 5 or 6, wherein the image display means displays the image after the whitening process, and the instruction means changes the degree of the whitening process on the original image. It is further characterized by the provision. Thus, the user can instruct the degree of whitening processing step by step or continuously while viewing the image after the whitening processing displayed on the image display means, and can execute the desired whitening processing.

  The image processing apparatus according to claim 5 or 6, wherein the image display means displays a plurality of images after whitening processing with different degrees of whitening processing on the original image, and the displayed plurality of images. And a selecting means for selecting one image from the images. That is, a plurality of images after whitening processing having different whitening processing levels (for example, strong, medium, weak, etc.) prepared in advance are generated and displayed on the image display means. Select an image.

  A printer according to a fifteenth aspect includes the image processing apparatus according to any one of the fifth to fourteenth aspects, and a printing unit that prints an image subjected to whitening by the image processing apparatus on photographic paper. Yes.

  According to a sixteenth aspect of the present invention, the printer according to the fifteenth aspect further includes a camera that captures a person and acquires a digital original image.

The image processing program according to claim 17 is a highlight of the first blurred image based on a function of generating a first blurred image from a digital original image and brightness of each pixel of the first blurred image. A process of making the pixels of only the portion brighter , and performing a gradation conversion so that the pixels of only the highlight portion of the first blurred image are convex upward according to the brightness . A function for generating a blurred image, a function for generating a difference image obtained by subtracting the first blurred image from the original image, and an image obtained by adding the second blurred image and the difference image to perform whitening. It is characterized by having a computer realize the function to be generated.

An image processing program according to claim 18 is an original image corresponding to a pixel of only a highlight portion of the blurred image based on a function of generating a blurred image from a digital original image and brightness of each pixel of the blurred image. A correction amount for increasing the brightness of the pixels of the highlight portion, and a correction amount that is convex upward according to the brightness of the pixels of the highlight portion, and the correction amount obtained for the original image And a function of generating a whitened image by adding the image to a computer.

  According to the present invention, since the blurred image of the original image to be processed is generated and the process of brightening the highlight portion (whitening process) is performed using the blurred image, for example, the unevenness of the face, etc. High-frequency components that carry detail information are retained, and whitening processing can be performed without losing the stereoscopic effect of the highlight portion in the original image.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an image processing method, apparatus, program, and printer according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an embodiment of a printer according to the present invention.

  As shown in the figure, the printer 100 of this embodiment is an amusement sticker printing machine installed at a game center or a store, and mainly includes a camera unit 110, an image processing unit 120, a display control unit 130, The display 140 includes a central processing unit (CPU) 150, a main memory 160, a storage 170, a print engine 180, and an operation unit 190.

  The camera unit 110 captures a user's face and outputs digital color image data (R, G, B signals). The image processing unit 120 is prepared in advance with a function for performing image processing according to the present invention (hereinafter referred to as “whitening process”) based on the R, G, and B signals output from the camera unit 110 and a face image of the user. For example, a function for synthesizing a template image or graffiti, and a function for creating data for printing from the synthesized image data. Details of the whitening process will be described later.

  The image processing unit 120 converts R, G, and B signals that have undergone various types of image processing into Y, M, and C (yellow, magenta, and cyan) signals, and converts the converted Y, M, and C signals to the print engine 180. Output to.

  The display control unit 130 creates image data for display for displaying the user's face image on the display 140 from the image data (image data indicating a moving image) input from the camera unit 110, and this is displayed on the display 140. The image is output and displayed, and the synthesized image obtained by synthesizing the user's face image and the template image prepared in advance is displayed on the display 140, and further, the whitened image after photographing is displayed. .

  The CPU 150 is a processing unit that performs overall control of the entire system. By the CPU 150, a shooting instruction to the camera unit 110, reading of image data from the camera unit 110, processing instructions for the read image data, and each control Various instructions such as delivery of image data to the block and execution of printing are given. Various processing instructions to the CPU 150 are given from the operation unit 190 based on user operations. For example, the operation unit 190 is configured to select a template image used for image composition while viewing a template image displayed on the display device 140, a button for selecting a print type to be printed, and a degree of whitening processing. It has a button to select or an operation lever. Note that the operation unit 190 may be realized by a soft button of a touch panel on the display 140.

  The main memory 160 stores a control program for the printer and is used as a work area when the program is executed. The storage 170 is a non-volatile storage unit, and includes various template images and look-up tables (LUTs) for whitening processing. ) Etc. are stored.

  The print engine 180 employs, for example, a TA (Thermo Autochrome) system as a printing system, and heats color photographic paper (hereinafter referred to as “TA paper”) having C, M, and Y color layers. It is colored and fixed by irradiation with light of a predetermined wavelength, and has means for conveying TA paper, a thermal head, a fixing lamp, and the like. When printing a color image on TA paper, the TA paper is first transported and the thermal head is controlled by the Y signal to develop the yellow layer of the TA paper, and then the yellow color is fixed by the fixing lamp. Color development of the magenta layer and cyan layer of the TA paper is similarly performed based on the M signal and the C signal, thereby printing a color image on the TA paper. The printer of this embodiment is a TA printer. However, the present invention is not limited to this, and the present invention can also be applied to other types of printers such as other thermal printers and inkjet printers.

  Next, the whitening processing unit in the image processing unit 120 will be described.

  FIG. 2 is a block diagram showing a first embodiment of the whitening processing unit in the image processing unit 120.

  The whitening processing unit 200 shown in FIG. 1 includes a blurred image generation unit 202, a whitening look-up table (LUT) 204, a subtracter 206, and an adder 208. The whitening processing unit 200 has a 3-channel processing system in which original images R / G / B for each color of R (red), G (green), and B (blue) are input. In FIG. 2, only one channel is shown.

  The blurred image generation unit 202 generates a first blurred image based on the input digital original image R / G / B.

  FIG. 3 is a flowchart of a processing procedure in the blurred image generation unit 202, and FIG. 4 is a diagram illustrating an image of each process in the blurred image generation unit 202.

  The blurred image generation unit 202 inputs a digital original image R / G / B. An example of the original image R / G / B (image (1)) is shown in FIG.

  The blurred image generation unit 202 generates an image (2) reduced by decimating the image (1) (step S10 in FIG. 3, FIG. 4B). As shown in FIG. 4B, the image size (number of pixels) of the reduced image (2) is ¼ of the number of pixels of the original image (1), so the subsequent processing reduces the computation time. can do.

  Subsequently, the blurred image generation unit 202 applies the IIR low-pass filter (LPF) to the reduced image (2) to generate a blurred image (3) (step S12, FIG. 4C).

  FIG. 5 shows a model of IIR type LPF. As shown in the figure, the IIR type LPF includes an adder 202A, a one-pixel delay element 202B, and multipliers 202C and 202D. In the multipliers 202C and 202D, predetermined filter coefficients α and (1−α) are multiplied.

  The blurred image (3) is obtained by applying the IIR LPF having the above configuration to the input image (2) four times in the vertical and horizontal directions. Further, the filter coefficient α is appropriately 31/32, 15/16, 7/8, or the like.

  The filter for generating the blurred image (3) is not limited to the IIR LPF, and may be, for example, an FIR LPF, or any filter as long as it digitally blurs the image.

  Next, the blurred image (3) is enlarged twice to generate a blurred image (4) having the same number of pixels as the original image (1) (step S14, FIG. 4D). The enlargement process of the blurred image (3) is performed by interpolating the brightness data of adjacent pixels to generate a new pixel. Note that the reduction and enlargement processes in steps S10 and S14 are 1/2 thinning and x2 enlargement in FIG. 3, but not limited to this, 1/3 thinning, x3 enlargement, or 1/4 thinning, × 4 enlargement may be used.

  Returning to FIG. 2, the first blurred image generated by the blurred image generation unit 202 is output to the whitening LUT 204 and the subtractor 206.

  The whitening LUT 204 is, for example, a gradation conversion table in which an 8-bit output signal is stored corresponding to an 8-bit (0-255) input signal. For example, the input / output characteristics shown in the graph of FIG. 6 are stored. ing. That is, as shown in the figure, the whitening LUT 204 performs gradation conversion on the input / output characteristics indicated by the dotted line so that the highlight portion is convex upward (becomes brighter). The blurred image (second blurred image) whose gradation is converted so that the highlight portion becomes brighter by the whitening LUT 204 is output to the adder 208.

  The subtractor 206 subtracts the first blurred image from the original image R / G / B and outputs an image (difference image) indicating the difference value to the adder 208. This difference image is information including a shadow of the original image R / G / B (for example, a shadow indicating the unevenness of the face).

  The adder 208 adds the second blurred image input from the whitening LUT 204 and the difference image, and outputs the added image as an image R ′ / G ′ / B ′ after whitening processing. The image R ′ / G ′ / B ′ after the whitening process is an image in which the stereoscopic effect of the original image is not lost and the highlight portion becomes brighter.

  FIG. 7 is a block diagram showing a second embodiment of the whitening processing unit in the image processing unit 120.

  The whitening processing unit 210 shown in FIG. 1 includes a luminance / color difference (Y / C) processing unit 212, a blurred image generation unit 214, a whitening LUT 216, a subtracter 218, an adder 220, and a matrix processing unit 222. It is configured.

The Y / C processing unit 212 generates a luminance image Y and color difference images C _b and C _r based on the input digital original image R / G / B. Image Y is output to the blurred image generating unit 214, an image C _b, C _r is output to the matrix processing unit 222.

  The blur image generation unit 214, the whitening LUT 216, the subtractor 218, and the adder 220 perform whitening processing on the image Y. The blur image generation unit 202, the whitening LUT 204, the subtractor 206, and the adder 208 illustrated in FIG. Since the same processing is performed, detailed description is omitted here.

The image Y ′ obtained by performing the whitening process on the image Y output from the adder 220 is added to the matrix processing unit 222. Images C _b and C _r are added to other inputs of the matrix processing unit 222. The matrix processing unit 222 performs R, R based on the image Y ′ subjected to whitening processing and the images C _b and C _r . The image R ′ / G ′ / B ′ after the whitening process of G and B is generated.

  FIG. 8 is a block diagram showing a third embodiment of the whitening processing unit in the image processing unit 120.

  The whitening processing unit 230 shown in the figure includes a blurred image generation unit 232, a whitening LUT 234, and an adder 236. The whitening processing unit 230 has a three-channel processing system for inputting R, G, and B original images R / G / B for each color, but in FIG. Show.

  The blurred image generation unit 232 generates a blurred image based on the input original image R / G / B, and outputs the generated blurred image to the whitening LUT 234. Note that the blur image generation unit 232 performs the same processing as the blur image generation unit 202 illustrated in FIG. 2, and thus detailed description thereof is omitted here.

  The whitening LUT 234 is, for example, a conversion table in which a correction amount smaller than 8 bits is stored corresponding to an input signal of 8 bits (0 to 255). For example, the input / output characteristics shown in the graph of FIG. 9 are stored. ing. In other words, as shown in the figure, the whitening LUT 234 outputs a correction amount that is 0 for the shadow portion of the input signal and convex upward for the highlight portion.

  A correction amount that brightens only the highlight portion output from the whitening LUT 204 is added to the adder 236. The original image R / G / B is added to the other input of the adder 236. The adder 236 adds these two inputs, and the image R ′ / G after the whitening process is added to the added image. Output as '/ B'. The image R ′ / G ′ / B ′ after the whitening process is the same image as that of the first embodiment shown in FIG. 2, and the stereoscopic effect of the original image is not lost and the highlight portion becomes brighter. It is an image.

  FIG. 10 is a block diagram showing a fourth embodiment of the whitening processing unit in the image processing unit 120.

  The whitening processing unit 240 shown in the figure includes a Y / C processing unit 242, a blurred image generation unit 244, a whitening LUT 246, an adder 248, and a matrix processing unit 250.

  The Y / C processing unit 242 and the matrix processing unit 250 are the same as the Y / C processing unit 212 and the matrix processing unit 222 of the whitening processing unit 210 of the second embodiment shown in FIG. The generation unit 244, the whitening LUT 246, and the adder 248 perform whitening processing on the image Y, and perform the same processing as the blurred image generation unit 232, whitening LUT 234, and adder 236 shown in FIG. Detailed description is omitted.

  The whitened image R ′ / G ′ / B ′ output from the matrix processing unit 250 of the whitening processing unit 240 is the same image as that of the second embodiment shown in FIG. This is an image in which the feeling is not lost and the highlight portion becomes brighter.

  By the way, when a user is photographed by the camera unit 110 shown in FIG. 1, the aperture value and the shutter speed are determined and photographed so that the highlight portion is slightly under-saturated so as not to be saturated.

In this case, a histogram showing the density distribution of the captured image is as shown in FIG. That is, a gap is generated between the right end value (X _max ) of the histogram and 255 which is the maximum value of 8 bits. Since there is no input information in this gap portion, it is preferable to correct the level so that the right end value (X _max ) of the histogram becomes 255.

In order to set the right end value (X _max ) of the histogram to 255, gradation correction is performed by a level correction LUT having input / output characteristics indicated by a solid line in FIG. This level correction LUT uses the original image R / G / B as input information, and outputs the original image R / G / B after gradation correction. Further, this level correction LUT can be integrated with the whitening LUT shown in FIG. 6 to form one LUT.

  FIG. 13 is a flowchart showing a processing procedure from photographing by the user to printing out a photo sticker by the amusement sticker printing machine shown in FIG.

  As shown in the figure, first, a user's face image is photographed by the camera unit 110 (step S10). For example, six frames are shot while changing poses and facial expressions. Next, images for six frames are displayed on the display 140 on a multi-screen, and the user is allowed to select an image to be printed from among the six frames (step S12). In this embodiment, four frames are selected.

  Subsequently, the image after the whitening process of the selected first frame image is displayed on the display 140 (step S14). The image displayed on the display 140 is a thinned or reduced image having a pixel density that is coarser than the image to be printed. In this case, the cutoff frequency of the LPF for generating a blurred image is also low in pixel density. It is desirable to shift by minutes.

  While viewing the image displayed on the display 140, the user operates the operation unit 190 to instruct a desired brightness (whitening process). That is, as shown in FIG. 14, a LUT with a high degree of whitening (LUT indicated by a solid line), a LUT with a normal degree of whitening (LUT indicated by a one-dot chain line), and a LUT with a low degree of whitening (shown by a broken line). 3 LUTs) are prepared in advance, and the user is allowed to select the intensity of the whitening process using the buttons and operation levers of the operation unit 190. Thereby, the user can perform favorite whitening processing. Note that the degree of whitening processing may be instructed in stages such as strong, medium, and weak, or may be instructed continuously from strong to weak. When continuously instructing the degree of whitening processing, for example, an appropriate LUT may be created by interpolating three LUTs shown in FIG. 14 and using the LUT.

  When the degree of whitening processing is instructed as described above, whitening processing is performed in accordance with the instruction, and the image after whitening processing displayed on the display 140 is updated.

  In addition, a plurality of images after whitening processing having different levels of whitening processing such as strong, medium, and weak are displayed on a multi-screen on the display 140, and the user's favorite whitening processing is selected from the images displayed on the multi-screen. The selected image may be selected by the operation unit 190.

  When the whitening process of the image of the first frame is determined, the image display showing the processing result for determining the whitening process of each image of the second frame, the third frame, and the fourth frame in the same manner, and the degree of the whitening process Is designated (steps S18 to S28).

  When the whitening process for each frame is determined and the print button is pressed, the whitening LUT applied to the whitening process for each frame image is determined, and the whitening process is performed on the print image using the whitening LUT (step S30).

  FIG. 15 is a block diagram showing another embodiment of the blurred image generation unit 202 shown in FIG.

  The blur image generation unit 300 shown in the figure includes a luminance weight signal generation unit 310 and a luminance weighted blur image generation unit 320.

The luminance weight signal generation unit 310 includes a matrix circuit 312, a low-pass filter 314, and a weight (weight) signal calculation circuit 316. The matrix circuit 312 calculates a luminance signal Y by the following equation based on the input R, G, and B color signals, and outputs the luminance signal Y to the low-pass filter 314.
[Equation 1]
Y = 0.3 R + 0.6 G + 0.1 B
The low pass filter 314 calculates an average luminance value YL of the luminance signals Y of surrounding 5 × 5 pixels including the target pixel, and outputs the luminance value YL to the weight signal calculation circuit 316. It should be noted that the low-pass filter 314 can output a luminance value YL whose change is gradual even if the luminance signal Y in a region where the luminance changes abruptly is input.

In the weight signal calculation circuit 316, luminance weight table parameters Y1, Y2, and Wdark as shown in the graph of FIG. 16 are set, and the weight signal generation unit 316 inputs the input luminance value YL and the luminance weight table parameter Y1. , Y2, and Wdark are used to calculate the luminance weight signal W by the following equation.
[Equation 2]
W = Wdark (0 ≦ YL <Y1)
W = {(1.0−Wdark) / (Y2−Y1)} (YL−Y2) +1.0
(Y2 ≦ YL <Y2)
W = 1.0 (Y2 ≦ YL)
The luminance weight signal W calculated in this way becomes a smaller value as the luminance decreases. Instead of the weight signal calculation circuit 316, an LUT having the input / output characteristics shown in the graph of FIG. 16 may be used.

  On the other hand, the luminance weighted blur image generation unit 320 includes a blur image generation unit 321, multipliers 322 and 323, a subtracter 324, and an adder 325. The blurred image generation unit 321 includes the IIR type LPF shown in FIG. Note that the blurred image generation unit 321 corresponds to the blurred image generation unit 202 in FIG. 2, and a detailed description thereof will be omitted.

  The blurred image generated by the blurred image generation unit 321 is output to the multiplier 322. The luminance weight signal W is added to the other input of the multiplier 322, and the multiplier 322 multiplies these two inputs and outputs the multiplied value to the adder 325.

  The original image R / G / B is added to one input of the multiplier 323, and the signal (1-W) obtained by subtracting the luminance weight signal W from 1 by the subtractor 324 is added to the other input. The subtractor 324 multiplies these two inputs and outputs the multiplied value to the adder 325.

  The adder 325 adds the multiplication values input from the multipliers 322 and 323, respectively, and outputs the addition value as a first blurred image.

  Next, the operation of the blurred image generation unit 300 configured as described above will be described.

  In the first blurred image output from the blurred image generation unit 300, the blur is small for the low-luminance pixels of the original image R / G / B, and the blur is large for the high-luminance pixels. .

  For example, if the blur is increased for a pixel in a low-luminance region such as a pupil, the area of the pupil is small, and the surrounding area is a white eye or a bright skin color region. The brightness is shifted to the brighter side (increased brightness). As a result of increasing the blur, if the brightness of the pupil area is shifted to the brightness that is whitened, the whitening process is also performed on the pupil area. Note that if the whitening process is performed so that the pupil is brighter than the original brightness, the sharpness disappears and the image becomes dull.

  The blur image generation unit 300 according to the embodiment illustrated in FIG. 15 is configured such that blur is reduced with respect to pixels in a low luminance region. That is, the pixels in the low luminance area are not shifted greatly to the brighter side. As a result, it is possible to prevent the whitening process from being performed on the pixels in the low luminance area (particularly, the area having a small area), and the effect of whitening the face while maintaining the pupil density can be obtained.

  Note that the blurred image generation unit 300 can also be applied to the blurred image generation unit 232 illustrated in FIG. 8. The blur generation units 214 and 244 shown in FIGS. 7 and 10 can also be applied. In this case, since the blur generation units 214 and 244 originally input the luminance signal Y, the blur image generation unit 300 includes The matrix circuit 312 for generating the luminance signal Y is not necessary.

  In the embodiment shown in FIG. 1, the amusement sticker printing machine has been described as an example. However, the present invention can also be applied to whitening processing by a general personal computer (personal computer).

  FIG. 17 is a system configuration diagram showing another embodiment of the image processing apparatus according to the present invention, which is composed of a personal computer (PC) 400 and its peripheral devices, a camera unit 410, a display 420 and a printer 430. ing.

  The PC 400 mainly includes a CPU 402 that controls the operation of each component, a main memory 404 that stores a control program for the apparatus and a work area when the program is executed, an operating system (OS) of a personal computer, and an image according to the present invention. A hard disk device 406 storing processing programs, various application software, images, and the like, an interface 408 for performing communication between the camera unit 410, the display unit 420, and the printer 430, a keyboard and a mouse (not shown), etc. Input means and a CD-ROM drive. The PC 400 having the above configuration is a well-known one, and a detailed description of each component will be omitted.

  The image processing program in the hard disk device 406 is installed, for example, by setting a CD-ROM on which the image processing program is recorded in the CD-ROM drive of the PC 400, or via a network (not shown). By starting this image processing program, the PC 400 can perform whitening processing similar to the whitening processing performed by the amusement sticker printing machine described above on the original image input from the camera unit 410 or the like. The image after the whitening process is displayed on the display device 420 and printed out by the printer 430.

FIG. 1 is a block diagram showing an embodiment of a printer according to the present invention. FIG. 2 is a block diagram showing a first embodiment of a whitening processing unit of the image processing unit shown in FIG. FIG. 3 is a flowchart showing a processing procedure in the blurred image generation unit shown in FIG. FIGS. 4A to 4D are diagrams showing images of the images at each processing stage of the blurred image generation unit. FIG. 5 is a diagram showing a model of the IIR low-pass filter. FIG. 6 is a diagram showing an example of the whitening LUT shown in FIG. FIG. 7 is a block diagram showing a second embodiment of the whitening processing unit of the image processing unit shown in FIG. FIG. 8 is a block diagram showing a third embodiment of the whitening processing unit of the image processing unit shown in FIG. FIG. 9 is a diagram showing an example of the whitening LUT shown in FIG. FIG. 10 is a block diagram showing a fourth embodiment of the whitening processing unit of the image processing unit shown in FIG. FIG. 11 is a histogram showing an example of the density distribution of a photographed image photographed by the camera unit of FIG. FIG. 12 is a diagram showing an LUT for performing tone conversion of the captured image having the density distribution shown in FIG. FIG. 13 is a flowchart showing a processing procedure from photographing by the user to printing out a photo sticker by the amusement sticker printing machine shown in FIG. FIG. 14 is a diagram showing an example of each whitening LUT of strong, medium and weak. FIG. 15 is a block diagram showing another embodiment of the blurred image generation unit. FIG. 16 is a graph used to explain the luminance weight table parameters Y1, Y2, and Wdark. FIG. 17 is a system configuration diagram showing another embodiment of the image processing apparatus according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100, 430 ... Printer, 110, 410 ... Camera part, 120 ... Image processing part, 130 ... Display control part, 140, 420 ... Display, 150, 402 ... Central processing unit (CPU), 160, 404 ... Main memory, 170, storage, 180, print engine, 190, operation unit, 200, 210, 230, 240 ... whitening processing unit, 202, 214, 232, 244300, 321 ... blurred image generation unit, 204, 216, 234, 246 ... whitening LUT, 206, 218, 324 ... subtractor, 208, 220, 236, 248, 325 ... adder, 212, 242 ... Y / C processing unit, 222, 250 ... matrix processing unit, 310 ... luminance weight signal generation unit, 312 ... Matrix circuit, 314 ... Low pass filter, 316 ... Weight signal calculation circuit, 320 ... Blur with luminance weight Image generation unit, 322, 323 ... multiplier, 406 ... hard disk drive

Claims (18)

Generating a first blurred image from a digital original image;
A process of making the pixels of only the highlight portion of the first blurred image brighter based on the brightness of each pixel of the first blurred image, the pixels of only the highlight portion of the first blurred image Generating a second blurred image by performing a gradation conversion process so as to be convex upward according to the brightness ;
Generating a difference image obtained by subtracting the first blurred image from the original image;
Adding the second blurred image and the difference image to generate a whitened image;
An image processing method comprising: Generating a blurred image from the original digital image;
Based on the brightness of each pixel of the blurred image, a correction amount for making the brightness of the pixel of the original image corresponding to only the pixel of the highlight portion of the blurred image brighter , the pixel of the highlight portion Obtaining a correction amount that is convex upward according to the brightness of
Adding the obtained correction amount to the original image to generate a whitened image;
An image processing method comprising:   The image processing method according to claim 1, wherein the original image is a color image made up of R, G, and B color images, and the whitening process is performed for each color image.   The image processing method according to claim 1, wherein the original image is a color image including a luminance image and a color difference image, and the whitening process is performed only on the luminance image. First blur image generation means for generating a first blur image from a digital original image;
A process of making the pixels of only the highlight portion of the first blurred image brighter based on the brightness of each pixel of the first blurred image, the pixels of only the highlight portion of the first blurred image Second blur image generation means for generating a second blur image by performing a gradation conversion process so as to be convex upward according to the brightness ,
Subtracting means for generating a difference image formed by subtracting the first blurred image from the original image;
Adding means for generating a whitened image by adding the second blurred image and the difference image;
An image processing apparatus comprising: A blurred image generating means for generating a blurred image from a digital original image;
Based on the brightness of each pixel of the blurred image, a correction amount for making the brightness of the pixel of the original image corresponding to only the pixel of the highlight portion of the blurred image brighter , the pixel of the highlight portion A correction amount generating means for calculating a correction amount that is convex upward according to the brightness of
Adding means for adding the obtained correction amount to the original image to generate a whitened image;
An image processing apparatus comprising:   The image processing according to claim 5, wherein the first blur image generation unit generates the first blur image so that blur is reduced with respect to a low-luminance pixel of the original image. apparatus.   The image processing apparatus according to claim 6, wherein the blur image generation unit generates the blur image so that blur is reduced with respect to a low-luminance pixel of the original image.   The image processing apparatus according to claim 5, wherein the original image is a color image including R, G, and B color images, and the whitening process is performed for each color image.   The image processing apparatus according to claim 5, wherein the original image is a color image including a luminance image and a color difference image, and the whitening process is performed only on the luminance image.   The second blurred image generation means has a look-up table for storing brightness information for making the pixels in the highlight portion of the first blurred image brighter in advance corresponding to the brightness information of the input pixels. The brightness information corresponding to each pixel of the first blurred image is read from the lookup table and output as the second blurred image each time the brightness information is input. An image processing apparatus according to 1.   The correction amount generation means stores in advance a correction amount for increasing the brightness of the pixel of the original image corresponding to the pixel of the highlight portion of the blurred image corresponding to the brightness information of the input pixel. The image processing apparatus according to claim 6, further comprising a table, wherein each time the brightness information of each pixel of the blurred image is input, a corresponding correction amount is read from the lookup table and output.   The image processing apparatus according to claim 5, further comprising: an image display unit that displays the image after the whitening process; and an instruction unit that changes a degree of the whitening process on the original image.   Image display means for displaying a plurality of images after whitening processing with different degrees of whitening processing on the original image, and selection means for selecting one image from the displayed plurality of images. The image processing apparatus according to claim 5 or 6.   15. A printer comprising: the image processing apparatus according to claim 5; and a printing unit that prints an image subjected to whitening by the image processing apparatus on a photographic paper.   The printer according to claim 15, further comprising a camera that captures a person and acquires a digital original image. A function for generating a first blurred image from a digital original image;
A process of making the pixels of only the highlight portion of the first blurred image brighter based on the brightness of each pixel of the first blurred image, the pixels of only the highlight portion of the first blurred image A function of generating a second blurred image by performing a gradation conversion process so as to be convex upward according to the brightness ,
A function of generating a difference image obtained by subtracting the first blurred image from the original image;
A function of adding the second blurred image and the difference image to generate a whitened image;
An image processing program for causing a computer to realize the above. A function to generate a blurred image from a digital original image;
Based on the brightness of each pixel of the blurred image, a correction amount for making the brightness of the pixel of the original image corresponding to only the pixel of the highlight portion of the blurred image brighter , the pixel of the highlight portion A function to obtain a correction amount that protrudes upward according to the brightness of
A function of adding the obtained correction amount to the original image and generating a whitened image;
An image processing program for causing a computer to realize the above.

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