Image processing method and system for reproducing color image using structural color replication

Abstract

The present application provides an image processing method for reproducing a color image by structural color replication, comprising: performing pre-press image processing on a first original image to obtain a second original image; separating RGB color channel information of the second original image to obtain three second sub-gray scale images; performing frequency modulation screening on the three second sub-gray scale images to obtain an r channel bitmap, a g channel bitmap and a b channel bitmap; converting the r channel bitmap, the g channel bitmap and the b channel bitmap into a gray scale mode according to a 1:1 ratio conversion image mode to obtain r channel gray scale, g channel gray scale and b channel gray scale; merging the three second sub-gray scale images and the r channel gray scale, the g channel gray scale and the b channel gray scale in an RGB channel mode to obtain a third image; extracting same color value pixels in the third image to obtain a plurality of third sub-images; merging the third sub-images into a special color image in a multi-channel mode to obtain a fourth image for simulating true color of the first original image.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of physical optical anti-counterfeiting and printing packaging, and in particular to an image processing method and system for reproducing a color image using structural color replication. BACKGROUND

[0002] In recent years, with the continuous introduction of new card materials and the rapid development of IC card technology, the use of card base materials is also changing. Some new card base materials that are environmentally friendly, resistant to high temperature, and can be stored for a long period of time have been introduced, such as PETG (modified PET), PC (polycarbonate), PC / PBT (PC and PBT blended material), etc. Different materials with different characteristics are selected according to different card making needs. Among them, PC (polycarbonate) material is a material with excellent properties such as rigidity, toughness, high transparency, high gloss on the surface, impact resistance, high temperature resistance, long service life of the card, and no harmful gas release at high temperature. It is applied to some high-end identification cards such as ID cards, passports, driver's licenses, and social security cards. At the same time, because PC has a high carbon content, adding a photosensitizer to PC material can use laser etching to make it black, so that the information of the cardholder can be etched inside the material, preventing tampering, counterfeiting, and ensuring the effectiveness of the information, and prolonging the service life of the card.

[0003] However, the color produced by laser etching is black, such as black and white photos and black text on important identification cards. Some people are reluctant to have black and white photos on important identification cards, considering them to be unattractive.

[0004] The existing PC card making process for implementing the cardholder's color photo is completed in a centralized manner at a printing card factory. Multiple cardholder photo information is printed on a large PC film through unified layout and inkjet printing, then the multiple layers of large PC film constituting the card are bound, laminated, and cut into single cards, the electronic chip is milled and packaged, the corresponding personalized electronic information is written, and after inspection, the cards are packaged and distributed to administrative service centers for issuance to individuals.

[0005] With the government's informationization construction, technological progress, and the requirement of convenient services, important identification cards also require fast issuance at administrative service centers.

[0006] In order to realize the PC certificate card holder color photo and the convenient issuance of the certificate at the administrative service center terminal, the solution provided by the certificate making system CN211000509U is: the first solution: connecting the color printer and the laser etching machine in the certificate making system: "…step one: the laser etching module is used for etching the user identity information on the target certificate in the form of laser etching on the to-be-printed area of the target certificate, and the user identity information includes image information and text information; step two: the UV color printing module is used for printing a color image above the image information printed by the laser etching module, so that the color image and the image information are aligned and overlapped with each other; step three: and the UV color printing module can also print a protective layer on the to-be-printed area of the target certificate, so as to play a protective and anti-fake role; …". However, the above method is only a mechanical process superposition, and the UV ink of the color photo image is attached to the surface of the certificate card. Even if the protective layer is printed on it, its protective effect is limited, and the UV ink protruding on the surface of the card is not beautiful, at the same time, the friction opportunity is increased, the personalized information is lost, and the service life of the certificate card is greatly reduced. SUMMARY

[0007] The purpose of the present application is to provide an image processing method and system for reproducing a color image by using structural color copying. Through the present application, true color images can be conveniently, efficiently and universally produced.

[0008] The technical solutions provided by the present application are as follows:

[0009] The present application provides an image processing method for reproducing a color image by using structural color copying, comprising:

[0010] Input a first original image, which includes a continuous-tone digital color image in RGB color mode;

[0011] Perform pre-press image processing on the first original image to obtain a second original image;

[0012] Separate the RGB color channel information of the second original image to obtain three second sub-gray images;

[0013] Perform frequency modulation screening on the three second sub-gray images to obtain an r channel bitmap, a g channel bitmap and a b channel bitmap;

[0014] Convert the mode of the r channel bitmap, the g channel bitmap and the b channel bitmap to a gray mode in a 1:1 ratio to obtain an r channel gray image, a g channel gray image and a b channel gray image;

[0015] Merge the r channel gray image, the g channel gray image and the b channel gray image in RGB channel mode to obtain a third image;

[0016] extracting pixels of the same color value in the third image to obtain a plurality of third sub-images;

[0017] merging the third sub-images into a special color image in a multi-channel mode to obtain the fourth image for simulating the true color of the first original image.

[0018] In some embodiments, the separating the RGB color channel information of the second original image to obtain three second sub-grayscale images comprises:

[0019] analyzing and separating the RGB color channel information of the original image to obtain three second sub-grayscale images, which are R channel grayscale image, G channel grayscale image and B channel grayscale image respectively.

[0020] In some embodiments, the merging the r channel grayscale image, the g channel grayscale image and the b channel grayscale image in an RGB channel mode to obtain a third image comprises:

[0021] setting the r channel grayscale image as R channel, the g channel grayscale image as G channel and the b channel grayscale image as B channel.

[0022] wherein the color values of R, G and B in the third image are all 255.

[0023] In some embodiments, the extracting pixels of the same color value in the third image to obtain a plurality of third sub-images comprises:

[0024] extracting pixels of 8 color values in the third image respectively to obtain third sub-images in 8-bit grayscale mode with the same image size;

[0025] adjusting the grayscale value of the third sub-image to K100%;

[0026] wherein the third sub-images comprise R channel grayscale image, G channel grayscale image, B channel grayscale image, Y channel grayscale image, M channel grayscale image, C channel grayscale image, W channel grayscale image and K channel grayscale image.

[0027] In some embodiments, the merging the third sub-images into a special color image in a multi-channel mode comprises:

[0028] setting a corresponding color special color for each of the third sub-images and merging the third sub-images.

[0029] In some embodiments, the setting a corresponding color special color for each of the third sub-images comprises:

[0030] setting the color special color of R channel grayscale image as red special color.

[0031] The color spot of the G channel grayscale image is set as a green spot color;

[0032] The color spot of the B channel grayscale image is set as a blue spot color;

[0033] The color spot of the Y channel grayscale image is set as a yellow spot color;

[0034] The color spot of the M channel grayscale image is set as a magenta spot color;

[0035] The color spot of the C channel grayscale image is set as a cyan spot color;

[0036] The color spot of the W channel grayscale image is set as a white spot color;

[0037] The color spot of the K channel grayscale image is set as a black spot color.

[0038] In some embodiments, the pre-press image processing of the first original image obtains a second original image, comprising:

[0039] The first original image is color adjusted and image size adjusted, so that the color of the output reconstructed image conforms to the preset color and the image size is the actual size matching the output resolution.

[0040] In some embodiments, further comprising: simulating the fourth image through a display to mix out the true color of the first original image.

[0041] In some embodiments, further comprising: using the fourth image to perform image filling on an SM film, so that a color image is reproduced on the SM film using structural color.

[0042] In some embodiments, the present application provides an image processing device for reproducing a color image using structural color, which applies the image processing method for reproducing a color image using structural color, comprising:

[0043] An input module is configured to input a first original image, wherein the first original image comprises a continuous-tone digital color image in RGB color mode;

[0044] A pre-press image processing module is configured to perform pre-press image processing on the first original image to obtain a second original image;

[0045] A separation module is configured to separate the RGB color channel information of the second original image to obtain three second sub-grayscale images;

[0046] A frequency modulation screening module is configured to perform frequency modulation screening on the three second sub-grayscale images to obtain an r channel bitmap, a g channel bitmap, and a b channel bitmap;

[0047] The conversion module is configured to convert the r channel bitmap, the g channel bitmap and the b channel bitmap into a mode of the image into a gray mode in a 1:1 ratio, to obtain a r channel gray image, a g channel gray image and a b channel gray image.

[0048] The merging module is configured to merge the r channel gray image, the g channel gray image and the b channel gray image in an RGB channel mode to obtain a third image.

[0049] The extraction module is configured to extract same color value pixels in the third image to obtain a plurality of third sub-images.

[0050] The acquisition module is configured to merge the third sub-images into a special color image in a multi-channel mode to obtain the fourth image for simulating the true color of the first original image.

[0051] The image processing method and device for reproducing a color image by using structural color provided by the application have at least the following beneficial effects:

[0052] The image processing method for reproducing a color image by using structural color provided by the application aims to ensure the fast issuance of certificates and realizes the presentation of personalized color photo information in a PC certificate card by a terminal certification system of an administrative service center, improves the aesthetic degree of the certificate card and prolongs the service life of the certificate card. BRIEF DESCRIPTION OF DRAWINGS

[0053] The above features, technical characteristics, advantages and implementation modes of the image processing method and device for reproducing a color image by using structural color will be further described in a clear and understandable manner in combination with the preferred embodiments and the accompanying drawings.

[0054] Figure 1 is a schematic diagram of one embodiment of the image processing method for reproducing a color image by using structural color provided by the application;

[0055] Figure 2 is a schematic diagram of the calculation and conversion by the CIE color space provided by the application;

[0056] Figure 3 is a schematic diagram of another embodiment of the image processing method for reproducing a color image by using structural color provided by the application;

[0057] Figure 4 is a structural schematic diagram of a PC certificate card film color photo printing system provided by the application. DETAILED DESCRIPTION

[0058] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, devices, circuits, and

[0059] It is to be understood that the terminology "includes", "has", "holds", "contains" and / or "comprising", when used in this specification and in the following claims, indicates the presence of the described features, integers, steps, operations, elements, and / or components but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0060] In order to make the drawing simple, only the parts related to the present application are shown in the drawings, and they do not represent the actual structure of the product. In addition, in order to make the drawing simple and easy to understand, in some drawings, only one of the parts with the same structure or function is shown schematically, or only one of them is marked. In this document, "one" not only means "only one", but also means "more than one" in some cases.

[0061] It should be further understood that the term "and / or" used in the description and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0062] In addition, in the description of the present application, the terms "first", "second", etc. are only used for differentiation of description, and cannot be understood as indicating or implying relative importance.

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, specific implementation manners of the present application will be described below with reference to the drawings. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.

[0064] One embodiment of the present application, as shown in Figure 1 An image processing method for reproducing a color image by structural color replication, comprising:

[0065] S101 inputting a first original image, the first original image comprising a continuous tone digital color image in RGB color mode;

[0066] S102 performing pre-press image processing on the first original image to obtain a second original image;

[0067] S103 separates the RGB color channel information of the second original image to obtain three second sub-gray images;

[0068] S104 frequency modulation screening on the three second sub-gray images to obtain r channel bitmap, g channel bitmap and b channel bitmap.

[0069] Specifically, the R channel gray image, the G channel gray image and the B channel gray image are frequency modulation screened to be named as r channel bitmap, g channel bitmap and b channel bitmap respectively. Thus, the continuous tone image is converted into a halftone binary dot array bitmap, and all dot array pixels of the bitmap carry the brightness information of each channel of the original image. It is particularly pointed out that the frequency modulation screening is preferred instead of amplitude modulation screening. The dot size of the frequency modulation screening is equal, and the dot distance changes randomly, which expresses the tone by controlling the density of the dot. The dot of the light tone part of the image is sparse, and the dot of the dark tone part of the image is dense.

[0070] The output resolution of the frequency modulation screening is set according to the output resolution of the laser dot array photo printer. Preferably, the output resolution is 1200 dpi-3400 dpi.

[0071] S105 converts the r channel bitmap, the g channel bitmap and the b channel bitmap into the gray mode according to the 1:1 ratio of the image mode to obtain the r channel gray image, the g channel gray image and the b channel gray image.

[0072] S106 merges the r channel gray image, the g channel gray image and the b channel gray image in the RGB channel mode to obtain a third image.

[0073] S107 extracts the same color value pixels in the third image to obtain a plurality of third sub-images.

[0074] S108 merges the third sub-images into a special color image in the multi-channel mode to obtain the fourth image for simulating the true color of the first original image.

[0075] In the embodiment, the image processing method for reproducing a color image by using structural color is provided, which is intended to realize the personal color photo information in the PC card of the administrative service center terminal certification system under the premise of quick certification, improve the appearance of the card and prolong the service life of the card.

[0076] In one embodiment, the separating the RGB color channel information of the second original image to obtain three second sub-gray images comprises:

[0077] The RGB color channel information of the original image is parsed and separated to obtain three second sub-gray images, which are R channel gray image, G channel gray image and B channel gray image respectively.

[0078] Specifically, the RGB color channel information of the second image is parsed and separated to form three independent second sub-gray images, which are named as R channel gray image, G channel gray image and B channel gray image. Common image processing software such as Photoshop can realize it.

[0079] In one embodiment, the r channel gray image, the g channel gray image and the b channel gray image are merged in RGB channel mode to obtain a third image, which includes:

[0080] The r channel gray image is set as R channel, the g channel gray image is set as G channel, and the b channel gray image is set as B channel.

[0081] Wherein, the color values of R, G and B in the third image are all 255.

[0082] Specifically, the three r channel gray images, g channel gray images and b channel gray images are merged into a third image in RGB channel mode. The gray mode image includes r channel gray image, g channel gray image and b channel gray image.

[0083] Wherein, the r channel gray image is set as R channel, the g channel gray image is set as G channel, and the b channel gray image is set as B channel.

[0084] The R, G and B color scale values in the merged image are all 255.

[0085] In the RGB three-channel dot matrix image, there are single-color light pixels that independently occupy a dot matrix position, there are mixed light pixels that overlap each other, and there are dot matrix positions that are not occupied by pixels. Their combination modes include the following eight kinds:

[0086] The red R channel 1 pixel alone occupies a dot matrix position and still displays red light, which is represented as: R ;

[0087] The green G channel 1 pixel alone occupies a dot matrix position and still displays green light, which is represented as: G ;

[0088] The blue B channel 1 pixel alone occupies a dot matrix position and still displays blue light, which is represented as: B ;

[0089] One pixel in the red (R) channel, superimposed with one pixel in the green (G) channel, occupies one pixel position and is displayed as yellow light, represented as: R+G = Y ;

[0090] One pixel in the red (R) channel, superimposed with one pixel in the green (B) channel, occupies one pixel position in the matrix and is displayed as magenta light, represented as: R + B = M ;

[0091] One pixel in the green (G) channel, superimposed with one pixel in the blue (B) channel, occupies one pixel position and is displayed as cyan light, represented as: G+B = C ;

[0092] One pixel from the red (R) channel, one pixel from the green (G) channel, and one pixel from the blue (B) channel occupying one pixel position in the pixel matrix, are displayed as white light, represented as: R+G+B = W ;

[0093] A pixel location with no pixels is displayed as black, i.e., no light. K .

[0094] In one embodiment, extracting pixels of the same color value from the third image to obtain multiple third sub-images includes:

[0095] The pixels with the eight color values ​​in the third image are extracted to obtain a third sub-image of the same image size in 8-bit grayscale mode.

[0096] Adjust the grayscale value of the third sub-image to K100%;

[0097] The third sub-image includes an R-channel grayscale image, a G-channel grayscale image, a B-channel grayscale image, a Y-channel grayscale image, an M-channel grayscale image, a C-channel grayscale image, a W-channel grayscale image, and a K-channel grayscale image.

[0098] Specifically, extract pixels of the same color value from the third image and create a new third sub-image. Then, extract the pixels of the same color value from the third image. R , G , B , Y , M , C , W , K Pixels of each of the eight color values ​​were extracted, and three separate 8-bit grayscale sub-images of the same size were created. The grayscale value was adjusted to K100%, and each sub-image was named... R Channel grayscale image, G Channel grayscale image, B Channel grayscale image, Y Channel grayscale image, M Channel grayscale image, C Channel grayscale image,W channel gray scale image, K channel gray scale image. Prepare for the next step of merging channel operation.

[0099] In one embodiment, the third sub-image is merged into a multi-channel mode special color image, comprising:

[0100] Set a corresponding color special color for each third sub-image, and merge the third sub-image.

[0101] In one embodiment, the third sub-image is set to a corresponding color special color, comprising:

[0102] The color special color of the R channel gray scale image is set to red special color;

[0103] The color special color of the G channel gray scale image is set to green special color;

[0104] The color special color of the B channel gray scale image is set to blue special color;

[0105] The color special color of the Y channel gray scale image is set to yellow special color;

[0106] The color special color of the M channel gray scale image is set to magenta special color;

[0107] The color special color of the C channel gray scale image is set to cyan special color;

[0108] The color special color of the W channel gray scale image is set to white special color;

[0109] The color special color of the K channel gray scale image is set to black special color.

[0110] In one embodiment, the first original image is pre-press image processed to obtain a second original image, comprising:

[0111] The first original image is color adjusted and image size adjusted, so that the color of the output reconstructed image conforms to the preset color and the image size is the actual size matching the output resolution.

[0112] Specifically, in addition to the conventional processing such as beautification editing and layout, necessary color adjustment and image size adjustment are performed to ensure that the color of the output reconstructed image is optimal and the actual size matches the output resolution. The color adjustment here also includes the specific color space conversion calculation in technical solution one.

[0113] In one embodiment, it further comprises simulating the fourth image through a display to mix the true color of the first original image.

[0114] Specifically, by using the Photoshop image processing software, the true color of the first original image can be mixed by simulating 8-channel spot color synthesis on the display.

[0115] In one embodiment, further comprising: image filling the SM film with the fourth image so that the color image is reproduced on the SM film by structural color replication.

[0116] Specifically, the SM film is image filled based on the above-mentioned image processing method and device, so that the color image is reproduced on the SM film by structural color replication.

[0117] Different pulse energies and scanning speeds produce different structural colors. And the color in the overlapping area will change.

[0118] The ultrafast laser receives different color etching instructions of the image processing system, and performs etching operation with different energies on different positions of the SM film, that is, etching with a preset thickness on different positions of the SM film, so that different structural colors are presented on the SM film, and finally the corresponding true color image is reproduced on the SM film.

[0119] In one embodiment, the present application provides an image processing device for reproducing color images by structural color replication, which applies the image processing method for reproducing color images by structural color replication, comprising:

[0120] An input module is configured to input a first original image, wherein the first original image comprises a continuous-tone digital color image in RGB color mode;

[0121] A pre-press image processing module is configured to perform pre-press image processing on the first original image to obtain a second original image;

[0122] A separation module is configured to separate RGB color channel information of the second original image to obtain three second sub-gray scale images;

[0123] A frequency modulation screening module is configured to perform frequency modulation screening on the three second sub-gray scale images to obtain an r channel bitmap, a g channel bitmap and a b channel bitmap;

[0124] A conversion module is configured to convert the mode of the r channel bitmap, the g channel bitmap and the b channel bitmap to a gray scale mode according to a 1:1 ratio to obtain an r channel gray scale image, a g channel gray scale image and a b channel gray scale image;

[0125] A merging module is configured to merge the r channel gray scale image, the g channel gray scale image and the b channel gray scale image in RGB channel mode to obtain a third image;

[0126] An extraction module is configured to extract same color value pixels in the third image to obtain a plurality of third sub-images;

[0127] The acquisition module is configured to merge the third sub-image into a spot color image in a multi-channel mode to obtain the fourth image for simulating true color of the first original image.

[0128] In one embodiment, the present application provides an image processing method for reproducing a color image by structural color copying, specifically comprising:

[0129] Researchers from the Westlake University, including Geng Jiao and Shi Liping, published a paper in the Journal of the Chinese Optical Engineering Society

[0130] The paper "Wear-resistant structural color based on superhard ceramic materials" published on PhotoniX (June 28, 2022) presents a super-thin color optical coating with super wear resistance realized by three superhard ceramic materials: titanium nitride (TiN), aluminum nitride (AlN), and titanium aluminum nitride (TiAlN). Researchers used the high loss (large imaginary part of refractive index) of TiAlN in the visible and near-infrared bands and the metal-like complex refractive index of TiN to construct a SM thin film with a total thickness of <100 nm. By changing the thickness of the TiAlN absorption layer with ultrafast laser, the SM thin film can exhibit bright reflective structural color. In addition, due to the extremely thin film thickness of the SM thin film, changing the incident angle within a large range will not cause significant phase shift. Unlike traditional Fabry-Perot thin films, the SM thin film has the characteristic that the structural color is independent of the incident angle, realizing a thin film structural color with the same transmission and reflection colors.

[0131] Based on this research result, combined with the practical demand of presenting personalized color photos on PC certificates and fast terminal issuance, the present application proposes a new solution:

[0132] An SM film is arranged on the surface of the PC film at the portrait position. The PC film with the SM film on the surface is hot laminated with other printed films, laser films, protective films, chip packaging layers, and other materials to produce a blank PC card. The blank PC card is input into the terminal issuance system of the administrative service center. When the blank PC card runs to the photo printing station, the color photo printing system in the PC card film prints a personalized color photo on the surface of the SM film by laser, realizing the purpose of presenting personalized color photo information in the PC card by the terminal issuance system of the administrative service center. In addition, since the SM film is arranged inside the card, it is necessary to damage the card surface to replace the portrait and other personal information, thereby achieving the anti-counterfeiting effect.

[0133] However, the current "anti-wear structural color based on superhard ceramic material" only proves that the thin film of SM can present bright reflective structural color, and in fact, it is only filled with a certain color pattern, not an image, not to copy the real color of the original image, so the problem of "how to copy the real color image on the SM film" needs to be solved first.

[0134] Based on the color mode and color space theory of digital image, RGB model is a commonly used color information expression method, which uses the brightness of red, green and blue three primary colors to quantitatively represent color. CIE (International Commission on Illumination) stipulates that 700nm (red), 545.1nm (green) and 435.8nm (blue) are three primary colors, also known as physical three primary colors. The digital image acquired by digital camera is in RGB mode, in which mode each image has R, G and B values, and each value can be taken from 0 to 255. In accordance with the principle of color light additive color method, the larger the value, the brighter the color, that is, the larger the RGB value, the brighter the color. RGB is 255 for white color, and RGB value is 0 for black color. Each value of RGB has 256 possibilities, so the color represented in this mode can have 256*256*256 = 216, that is, more than 1670 million colors. The image in RGB mode is called true color image.

[0135] Although the structural color produced by the laser effect introduced in the background art is rich, it still cannot produce structural reflection of red (R), green (G), blue (B) and yellow (Y), magenta (M) and cyan (C) wavelengths by accurately applying laser dose. Therefore, after measuring the actual color, calculation and conversion are carried out through CIE color space, as shown in Figure 2 .

[0136] As shown in Figure 3 , the method steps for realizing multi-channel color mixing and reconstructing color image include:

[0137] First step, input the original image. Input a continuous tone digital color image in RGB color mode, defined as the first original image.

[0138] Second step, pre-press image processing is carried out on the first original image to obtain the second image.

[0139] In addition to the conventional processing such as beautification, editing and layout, necessary color adjustment and image size adjustment should be carried out to ensure that the color of the output reconstructed image is optimal and the actual size matches the output resolution. The color adjustment here also includes the specific color space conversion calculation in technical solution one.

[0140] Third step, separate channel. The RGB color channel information of the second image is parsed and separated to form three independent second sub-gray images, named: R channel gray image, G channel gray image, B channel gray image. Common image processing software such as Photoshop can achieve this.

[0141] Fourth step, frequency modulation screening. R channel gray image, G channel gray image, B channel gray image are screened respectively, and are named as r channel bitmap, g channel bitmap, b channel bitmap.

[0142] In this way, the continuous tone image is transformed into a halftone binary dot bitmap, and all the dot pixels of the bitmap carry the brightness information of each channel of the original image. It is particularly pointed out that frequency modulation screening should be preferred instead of amplitude modulation screening. The dot size of frequency modulation screening is equal, and the dot distance changes randomly, which is used to express the tone by controlling the density of the dots. The dots of the light tone part of the image are sparse, and the dots of the dark tone part are dense.

[0143] The output resolution of frequency modulation screening is set according to the output resolution of the laser dot photolithography printer. Preferably, it is 1200dpi-3400dpi.

[0144] Fifth step, bitmap gray scale. The r channel bitmap, g channel bitmap, and b channel bitmap are converted to gray scale images in a 1:1 ratio, and are named as r channel gray, g channel gray, and b channel gray, respectively, to facilitate the next step of merging channel operation.

[0145] Sixth step, merge RGB channel. The three r channel gray, g channel gray, and b channel gray images are merged into a third image in RGB channel mode, in which the r channel gray is set as the R channel, the g channel gray is set as the G channel, and the b channel gray is set as the B channel.

[0146] Specifically, the original image is in gray scale mode after separating the channel, and becomes a black and white binary bitmap mode (non-gray scale mode) after frequency modulation screening, but the three images need to be merged into one RGB mode image. Figure 1 Therefore, there is a step of converting the bitmap to gray scale between the three gray scale images. Figure 4 :1 to gray scale is for this purpose.

[0147] The R, G, and B color scale values in the merged image are all 255. In the RGB three-channel dot array image, there are single-color light pixels that independently occupy one dot array position, mixed light pixels that overlap each other, and dot array positions that are not occupied by pixels, and their combination modes include the following eight types:

[0148] The red R channel 1 pixel alone occupies one dot array position and still displays red light, which is represented as: R;

[0149] Green G channel 1 pixel alone occupies a dot matrix position still shows green light, represented as: G;

[0150] Blue B channel 1 pixel alone occupies a dot matrix position still shows blue light, represented as: B;

[0151] Red R channel 1 pixel superimposed on a dot matrix position occupied by Green G channel 1 pixel shows yellow light, represented as: R+G=Y;

[0152] Red R channel 1 pixel superimposed on a dot matrix position occupied by Green B channel 1 pixel shows magenta light, represented as: R+B=M;

[0153] Green G channel 1 pixel superimposed on a dot matrix position occupied by Blue B channel 1 pixel shows cyan light, represented as: G+B=C;

[0154] Red R channel 1 pixel superimposed on a dot matrix position occupied by Green G channel 1 pixel and then superimposed on Blue B channel 1 pixel shows white light, represented as: R+G+B=W;

[0155] No pixel occupies a dot matrix position shows no light, that is, black, represented as: K.

[0156] The seventh step is to extract the same color value pixels in the third image and build a new third sub-image. The R, G, B, Y, M, C, W, K 8 color value pixels in the third image are extracted respectively, and 8-bit depth gray mode third sub-images of the same image size are newly built, the gray value is adjusted to K100%, and are named as R channel gray image, G channel gray image, B channel gray image, Y channel gray image, M channel gray image, C channel gray image, W channel gray image, K channel gray image respectively. Prepare for the next step of merging channel operation.

[0157] The eighth step is to merge the multi-channel image into a fourth image. The R channel gray image, G channel gray image, B channel gray image, Y channel gray image, M channel gray image, C channel gray image, W channel gray image, K channel gray image 8 gray images are merged into a multi-channel mode special color image. Among them, the R channel gray image is set as red special color, the G channel gray image is set as green special color, the B channel gray image is set as blue special color, the Y channel gray image is set as yellow special color, the M channel gray image is set as magenta special color, the C channel gray image is set as cyan special color, the W channel gray image is set as white special color, and the K channel gray image is set as black special color. The fourth image thus reproduces the true color of the first original image.

[0158] Through Photoshop image processing software, 8-channel special color synthesis can mix out the true color of the first original image on the display.

[0159] In the embodiment, the 8-channel color group contains all pixels of the image, does not overlap each other, does not miss any point, and has high resolution and clear image.

[0160] The application preserves more color information, and can obtain a luminance plane with little or no distortion during reconstruction, thereby obtaining not only a high-quality gray-scale image, but also a high-quality reconstructed color image.

[0161] The application also provides a device comprising a laser dot array photoetching printer and a raster image processor for executing the method.

[0162] The SM film is filled with images based on the image processing method and device, so that the color image is reproduced on the SM film by using the structural color copying.

[0163] In the embodiment, different pulse energies and scanning speeds produce different structural colors, and the color in the overlapping area is changed.

[0164] The ultrafast laser receives different color etching instructions of the image processing system, and performs etching operation with different energies on different positions of the SM film, that is, etching with a preset thickness on different positions of the SM film, so that different structural colors are presented on the SM film, and finally the corresponding true color image is reproduced on the SM film.

[0165] On the other hand, as ​ shown, the application also provides a PC certificate card film color photo printing system. Under the premise of ensuring fast issuance of certificates, the terminal certificate issuing system of the administrative service center presents personalized color photo information in the PC certificate card, improves the wear resistance and aesthetic degree of the certificate card, prolongs the service life of the certificate card, and enhances the anti-forging characteristics.

[0166] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above program modules is taken as an example for illustration, and in actual application, the above functions can be completed by different program modules according to needs, that is, the internal structure of the device is divided into different program units or modules to complete all or part of the functions described above. Each program module in the embodiment can be integrated in one processing unit, or each unit can be physically present alone, or two or more units can be integrated in one processing unit. The integrated unit can be realized in the form of hardware or in the form of software program unit. In addition, the specific names of each program module are only for easy distinction, and do not limit the protection scope of the application.

[0167] It should be noted that the above embodiments can be freely combined as needed. The above only describes the preferred embodiments of the present application, and it should be pointed out that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application.

Claims

1. An image processing method for reproducing a color image using structural color replication, characterized by, The method comprises the following steps: inputting a first original image, wherein the first original image comprises a continuous-tone digital color image in RGB color mode; performing pre-press image processing on the first original image to obtain a second original image; separating RGB color channel information of the second original image to obtain three second sub-gray images; frequency-modulating and screening the three second sub-gray images to obtain an r channel bitmap, a g channel bitmap and a b channel bitmap; converting the r channel bitmap, the g channel bitmap and the b channel bitmap into a gray mode in a 1:1 ratio to obtain an r channel gray image, a g channel gray image and a b channel gray image; merging the r channel gray image, the g channel gray image and the b channel gray image in RGB channel mode to obtain a third image; extracting same-color-value pixels in the third image to obtain a plurality of third sub-images; merging the third sub-images into a special color image in a multi-channel mode to obtain a fourth image for simulating true colors of the first original image.

2. The image processing method for reproducing a color image using structural color replication according to claim 1, characterized by, The step of separating the RGB color channel information of the second original image to obtain three second sub-gray images comprises the following steps: analyzing and separating the RGB color channel information of the original image to obtain three second sub-gray images, which are an R channel gray image, a G channel gray image and a B channel gray image, respectively.

3. The image processing method for reproducing a color image using structural color replication according to claim 2, characterized in that, The step of merging the r channel gray image, the g channel gray image and the b channel gray image in RGB channel mode to obtain a third image comprises the following steps: setting the r channel gray image as an R channel, the g channel gray image as a G channel and the b channel gray image as a B channel; wherein the color values of R, G and B in the third image are all 255.

4. The image processing method for reproducing a color image using structural color replication according to claim 3, characterized by, The step of extracting same-color-value pixels in the third image to obtain a plurality of third sub-images comprises the following steps: extracting pixels with 8 color values in the third image to obtain third sub-images in 8-bit gray mode with the same image size; adjusting the gray values of the third sub-images to K100%; The third sub-image comprises R channel gray image, G channel gray image, B channel gray image, Y channel gray image, M channel gray image, C channel gray image, W channel gray image, K channel gray image.

5. The image processing method for reproducing a color image using structural color replication according to claim 4, characterized in that, The step of merging the third sub-images into a special color image in a multi-channel mode comprises the following steps: setting a corresponding color special color for each third sub-image and merging the third sub-images.

6. The image processing method for reproducing a color image using structural color replication according to claim 5, characterized in that, The step of setting a corresponding color special color for each third sub-image comprises the following steps: Will R The spot color of the grayscale image channel is set to red spot color; Will G The spot color of the grayscale image channel is set to green. The color spot of the channel grayscale image is set as a blue spot. B The color spot of the channel grayscale image is set as a blue spot. The color spot of the channel grayscale image is set as a yellow spot. Y The color spot of the channel grayscale image is set as a yellow spot. The color spot of the channel grayscale image is set as a magenta spot. M The color spot of the channel grayscale image is set as a magenta spot. Will C The color spot for the grayscale image channel is set to cyan spot color; The color spot of the channel grayscale image is set as a white spot. W The color spot of the channel grayscale image is set as a white spot. The color spot of the channel grayscale image is set as a black spot. K The color spot of the channel grayscale image is set as a black spot.

7. The image processing method for reproducing a color image using structural color replication according to any one of claims 1 to 6, characterized by, The step of performing pre-press image processing on the first original image to obtain a second original image comprises the following steps: color adjusting and image size adjusting the first original image, so that the color of the output reconstructed image meets the preset color and the image size is the actual size matching the output resolution.

8. The image processing method for reproducing a color image using structural color replication according to claim 7, characterized in that, The method further comprises the following steps: simulating the fourth image on a display to mix out true colors of the first original image.

9. The image processing method for reproducing a color image using structural color replication according to claim 8, characterized in that, The method further comprises the following steps: filling the fourth image on an SM film to reproduce a color image using structural color.

10. An image processing apparatus for reproducing a color image using structural color replication, characterized by comprising: The method for reproducing a color image using structural color comprises the following steps: an input module configured to input a first original image, wherein the first original image comprises a continuous-tone digital color image in RGB color mode; The pre-press image processing module is configured to perform pre-press image processing on the first original image to obtain a second original image. The separation module is configured to separate RGB color channel information of the second original image to obtain three second sub-gray scale images. The frequency modulation screening module is configured to perform frequency modulation screening on the three second sub-gray scale images to obtain an r channel bitmap, a g channel bitmap and a b channel bitmap. The conversion module is configured to convert the r channel bitmap, the g channel bitmap and the b channel bitmap into a gray scale mode according to a 1:1 ratio to obtain an r channel gray scale image, a g channel gray scale image and a b channel gray scale image. The merging module is configured to merge the r channel gray scale image, the g channel gray scale image and the b channel gray scale image in an RGB channel mode to obtain a third image. The extraction module is configured to extract same color value pixels in the third image to obtain a plurality of third sub-images. The acquisition module is configured to merge the third sub-images into a special color image in a multi-channel mode to obtain a fourth image for simulating true colors of the first original image.

Images