A method for color correction of ceramic printing

Abstract

The present invention discloses a color correction method for ceramic printing, which comprises the following steps: (1) Collecting the chromaticity values of the designed printing pictures; (2) Photographing the printed tiles; (3) Collecting the chromaticity values of the photographed pictures; (4) Calculating the color difference between the chromaticity values of the photographed pictures and the background; (5) Calculating the adjustment value of each color block; (6) Recalculating the chromaticity values of each color block of the output file; (7) Regenerating the output file in the Lab color model; (8) Outputting the ICC profile. The beneficial effects of the present invention are as follows: The present invention collects the color of the ceramic surface, compares it with the designed background color, corrects the color of the designed pattern file in units of color blocks, and finally outputs the corrected ICC profile for actual production, enabling high fineness and high color reproducibility after the printed patterns are overprinted.

Description

Technical Field

[0001] The present invention relates to a printing method, in particular to a color correction method for ceramic printing. Background Art

[0002] The patterns for ceramic printing are designed according to a specific background color. The color on the ceramic surface will be overlaid (registered) with the printed pattern to restore the color of the printed pattern. Since the designed pattern is based on a specific background color, in the actual production process, the surface color of ceramics such as ceramic tiles is affected by raw materials, firing processes, etc., and the color of the tile surface will deviate from the specific design. For the same tile, there are also deviations in the local parts of the entire surface, which results in deviations in the printed pattern after printing according to the designed pattern, and cannot meet the requirements of high fineness and high restoration of the printed pattern. Summary of the Invention

[0003] In order to overcome the deficiencies of the prior art, the present invention provides a color correction method for ceramic printing.

[0004] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0005] A color correction method for ceramic printing includes the following steps:

[0006] (1). Input the designed print picture into a computer, divide the picture into color blocks of 9 mm × 9 mm, identify the coordinates of each color block and the chromaticity value of each color block. The chromaticity value of the color block of the designed print picture with coordinates xy is denoted as: L*a*b* xy设计 .

[0007] (2). Under a black environment and a standard light source, use a area array camera to take a picture of the ceramic tile. The center point of the camera picture coincides with the center point of the pattern to be printed, and adjust the lens focal length to make the ceramic tile fill the entire camera picture.

[0008] (3). Input the taken photo into a computer, cut off the redundant part, trim the photo, adjust the image size to be the same as the designed print picture, divide the picture into color blocks of 9 mm × 9 mm, identify the coordinates of each color block and the chromaticity value of each color block. The chromaticity value of the color block of the taken photo with coordinates xy is denoted as: L*a*b* xy拍摄 .

[0009] (4). Use the CIE1976 color difference formula to calculate the color difference value △E xy拍摄 between the chromaticity value L*a*b* 背景 of each color block of the taken photo and the background chromaticity value Lab xy ; the color difference value △E xy is the chromaticity value of the taken photo with coordinates xy and the background chromaticity value Lab 背景Color difference value.

[0010] (5) Calculate the adjustment value Δ of each color patch xy；

[0011] Δ xy = △E xy * W1 + △E （x-1）y * W2 + △E （x+1）y * W3 + △E x（y-1） * W4 + △E x（y+1） * W5

[0012] where, Δ xy is the adjustment value of the color patch with coordinates xy.

[0013] W1, W2, W3, W4, W5 are weighting coefficients.

[0014] △E （x-1）y is the color difference value between the chromaticity value of the photographed image with coordinates (x - 1)y and the background chromaticity value Lab 背景 Color difference value.

[0015] △E （x+1）y is the color difference value between the chromaticity value of the photographed image with coordinates (x + 1)y and the background chromaticity value Lab 背景 Color difference value.

[0016] △E x（y-1） is the color difference value between the chromaticity value of the photographed image with coordinates x(y - 1) and the background chromaticity value Lab 背景 Color difference value.

[0017] △E x（y+1） is the color difference value between the chromaticity value of the photographed image with coordinates x(y + 1) and the background chromaticity value Lab 背景 Color difference value.

[0018] (6) Recalculate the chromaticity value L*a*b* of each color patch in the output file xy调整

[0019] L*a*b* xy调整 = L*a*b* xy设计 + Δ xy .

[0020] (7) Regenerate the output file in Lab mode according to the calculation results of each color patch.

[0021] (8) Convert the output file to CMYK color mode and output it as an ICC profile for actual production.

[0022] It is stated that W1 = 0.6, W2 = 0.1, W3 = 0.1, W4 = 0.1 、 W5 = 0.1.

[0023] The beneficial effects of the present invention are as follows: The present invention collects the color on the surface of the ceramic, compares it with the designed background color, corrects the color of the designed pattern file in units of color blocks, and finally outputs a corrected ICC profile for actual production, enabling high fineness and high color reproducibility after the printed patterns are overprinted. Embodiment

[0024] A color correction method for ceramic printing includes the following steps:

[0025] (1) Input the designed printed picture into a computer, divide the picture into color blocks of 9 mm × 9 mm, identify the coordinates of each color block and the chromaticity value of each color block. The chromaticity value of the color block in the designed printed picture with coordinates xy is denoted as: L*a*b* xy设计 . The size of the color block can also be changed according to the area size to be spray-painted.

[0026] (2) In a black environment and under a standard light source, use a area array camera to take a picture of the ceramic tile. The center point of the camera picture coincides with the center point of the pattern to be printed. Adjust the lens focal length so that the ceramic tile fills the entire camera picture.

[0027] (3) Input the taken photo into a computer, crop the redundant part in Photoshop, trim the photo, adjust the image size to be the same as that of the designed printed picture, divide the picture into color blocks of 9 mm × 9 mm, and in the graphic recognition software, identify the coordinates of each color block and the chromaticity value of each color block. The chromaticity value of the color block in the taken photo with coordinates xy is denoted as: L*a*b* xy拍摄 .

[0028] (4) Use the CIE1976 color difference formula to calculate the color difference ΔE between the chromaticity value L*a*b* of each color block in the taken photo xy拍摄 and the background chromaticity value Lab 背景 ; The color difference ΔE xy is the color difference between the chromaticity value of the taken photo with coordinates xy and the background chromaticity value Lab xy . 背景

[0029] (5) Calculate the adjustment value Δ xy；

[0030] Δ xy = △E xy * W1 + △E （x-1）y * W2 + △E （x+1）y * W3 + △E x（y-1） * W4 + △E x（y+1） * W5

[0031] Wherein, Δ xyAdjust the value for the color patch with coordinates xy.

[0032] W1, W2, W3, W4, and W5 are weighting coefficients. In this embodiment, W1 = 0.6, W2 = 0.1, W3 = 0.1, W4 = 0.1 、 W5 = 0.1.

[0033] △E （x-1）y is the color difference value between the chromaticity value of the captured photo with coordinates (x - 1)y and the background chromaticity value Lab 背景 of the color difference.

[0034] △E （x+1）y is the color difference value between the chromaticity value of the captured photo with coordinates (x + 1)y and the background chromaticity value Lab 背景 of the color difference.

[0035] △E x（y-1） is the color difference value between the chromaticity value of the captured photo with coordinates x(y - 1) and the background chromaticity value Lab 背景 of the color difference.

[0036] △E x（y+1） is the color difference value between the chromaticity value of the captured photo with coordinates x(y + 1) and the background chromaticity value Lab 背景 of the color difference.

[0037] In the above calculations, the color difference values of the color patches above, below, left, and right are considered. On the one hand, it can avoid shooting errors, and on the other hand, it can prevent large jumps in the colors of the picture.

[0038] (6), Recalculate the chromaticity values L*a*b* of each color patch in the output file xy调整

[0039] L*a*b* xy调整 = L*a*b* xy设计 +Δ xy .

[0040] (7), According to the calculation results of each color patch, regenerate the output file in Lab mode.

[0041] (8), Convert the output file into CMYK color mode and output it as an ICC profile for actual production.

[0042] The present invention collects the colors on the ceramic surface, compares them with the designed background color, corrects the colors of the designed pattern file in units of color patches, and finally outputs a corrected ICC profile for actual production, enabling high fineness and high color restoration after the printed patterns are overprinted.

[0043] The above embodiments cannot limit the protection scope of the present invention. Equivalent modifications and variations made by those skilled in the technical field without departing from the overall concept of the present invention still fall within the scope covered by the present invention.

Claims

1. A color correction method for ceramic printing, characterized in that Including the following steps: (1) Input the design printed picture into the computer, divide the picture into color patches of 9mm×9 mm, identify the coordinates of each color patch and the chromaticity value of each color patch, and record the chromaticity value of the color patch of the design printed picture with coordinates xy as: L*a*b* xy设计 ; (2) Under a black environment and a standard light source, use an area array camera to take a picture of the ceramic tile. The center point of the camera screen coincides with the center point of the pattern to be printed. Adjust the lens focal length so that the ceramic tile fills the entire camera screen; (3) Input the taken photo into the computer, crop the redundant part, retouch the photo, adjust the image size to be the same as the designed printed picture, divide the picture into color patches of 9 mm×9 mm, identify the coordinates of each color patch and the chromaticity value of each color patch, and record the chromaticity value of the color patch in the taken photo with coordinates xy as: L*a*b* xy拍摄 ; (4) Use the CIE1976 color difference formula to calculate the chromaticity values L*a*b* of each color patch in the photographed image xy拍摄 and the background chromaticity value Lab 背景 of the color difference value △E xy ; The color difference value △E xy is the color difference value between the chromaticity value of the photographed image with coordinates xy and the background chromaticity value Lab 背景 ; (5) Calculate the adjustment value Δ for each color block xy； Δ xy =△E xy *W1+△E （x-1）y *W2+△E （x+1）y *W3+△E x（y-1） *W4+△E x（y+1） *W5 where Δ xy is the adjustment value of the color block with coordinates xy; W1, W2, W3, W4, and W5 are weighting coefficients; △E （x-1）y is the color difference value between the chromaticity value of the photographed image with coordinates (x - 1)y and the background chromaticity value Lab 背景 ; △E （x+1）y is the chromaticity difference between the chromaticity value of the captured photo with coordinates (x + 1)y and the background chromaticity value Lab 背景 ; △E x（y-1） is the color difference value between the chromaticity value of the captured photo with coordinates x(y - 1) and the background chromaticity value Lab 背景 ; △E x（y+1） is the color difference value between the chromaticity value of the captured photo with coordinates x(y + 1) and the background chromaticity value Lab 背景 ; (6) Recalculate the chromaticity values L*a*b* of each color patch in the output file xy调整 L*a*b* xy调整 = L*a*b* xy设计 +Δ xy ; (7) According to the calculation results of each color block, regenerate the output file in the Lab color model; (8) Convert the output file into the CMYK color model and output it as the ICC profile for actual production.

2. The color correction method for ceramic printing according to claim 1, characterized in that It is described that W1 = 0.6, W2 = 0.1, W3 = 0.1, W4 = 0.1 、 W5 = 0.1.