Digital colourimetry method based on imaging device

Abstract

The invention discloses a digital colourimetry method based on an imaging device. According to application needs, two to three illumination bodies or light sources are selected, and a color card with the same medium as a shooting target sample is designed to serve as a training sample color card; a 45o / 0o illumination shooting environment is built, and parameters of the imaging device are set manually; digital images of the training sample color card and the target sample are obtained respectively on the basis, and illumination evenness and repeatability correction are carried out; by means of polynomials and other models, prediction from an RGB value of the target sample to CIEXYZ tri-stimulus values under the selected illumination bodies or the light sources is achieved, and prediction of a spectrum value is achieved by means of pseudo-inverse and other methods. The method can be widely used in the application fields with high color precision requirements for color image obtaining such as textiles, printing and dyeing, printing, leather, plastics, coating, paint, cultural relics, medical care, machine vision and artwork digital repositories and reproduction.

Description

technical field

[0001] The invention belongs to the field of image processing, and specifically relates to a digital color measurement method based on imaging equipment, which can be widely used in textiles, printing and dyeing, printing, leather, plastics, paints, paints, cultural relics, medical treatment, machine vision, digital art collections and Reproduction and other application fields that require high color accuracy for color image acquisition. Background technique

[0002] Color information has always been one of the key core indicators for product production control and quality evaluation in the fields of textiles, printing and dyeing, printing, leather, plastics, coatings, paints, medical treatment, machine vision, digital collection and reproduction of cultural relics and artworks, etc. . At present, in practical applications, the color information of objects is qualitatively or quantitatively described mainly by visual methods, colorimeters, and spectrophotome...

Examples

Embodiment Construction

[0028] Such as figure 1 As shown, the present invention is a digital color measurement method based on an imaging device. The spectral color measurement method based on a digital camera is taken as an example below to specifically illustrate the pixel-level digital imaging spectral color measurement method based on a digital imaging device. Specific steps are as follows:

[0029] Step 1: Select three illuminants of CIE A, D65 and E as the reference illuminants for calculating the tristimulus value of the sample CIEXYZ.

[0030] Step 2: Design a four-dimensional look-up table (LUT, Look Up Table) digital color card with a CMYK dot area of ​​0, 20, 40, 60, 80, and 100. It contains a total of 1296 color blocks, which are evenly distributed in the CMYK color space. The digital LUT color card is printed out by HP inkjet printer. Select the printed LUT color card as the training sample color card for digital color measurement. In addition, the ECI (European Color Initiative) colo...

technical field

[0001] The invention belongs to the field of image processing, and specifically relates to a digital color measurement method based on imaging equipment, which can be widely used in textiles, printing and dyeing, printing, leather, plastics, paints, paints, cultural relics, medical treatment, machine vision, digital art collections and Reproduction and other application fields that require high color accuracy for color image acquisition. Background technique

[0002] Color information has always been one of the key core indicators for product production control and quality evaluation in the fields of textiles, printing and dyeing, printing, leather, plastics, coatings, paints, medical treatment, machine vision, digital collection and reproduction of cultural relics and artworks, etc. . At present, in practical applications, the color information of objects is qualitatively or quantitatively described mainly by visual methods, colorimeters, and spectrophotome...

Examples

Embodiment Construction

[0028] Such as figure 1 As shown, the present invention is a digital color measurement method based on an imaging device. The spectral color measurement method based on a digital camera is taken as an example below to specifically illustrate the pixel-level digital imaging spectral color measurement method based on a digital imaging device. Specific steps are as follows:

[0029] Step 1: Select three illuminants of CIE A, D65 and E as the reference illuminants for calculating the tristimulus value of the sample CIEXYZ.

[0030] Step 2: Design a four-dimensional look-up table (LUT, Look Up Table) digital color card with a CMYK dot area of ​​0, 20, 40, 60, 80, and 100. It contains a total of 1296 color blocks, which are evenly distributed in the CMYK color space. The digital LUT color card is printed out by HP inkjet printer. Select the printed LUT color card as the training sample color card for digital color measurement. In addition, the ECI (European Color Initiative) colo...

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