White Balance Calibration Method of Color Digital Camera Based on Chromatic Adaptation Model

Abstract

The invention discloses a method for correcting the white balance of a color digital camera based on a color adaptation model. The invention uses a root-polynomial regression (Root-Polynomial Regression) method to calculate a color correction matrix, so that several common light sources (hereinafter referred to as calibration light sources) ) under the device-dependent response value RGB to the device-independent CIE1931 tristimulus value XYZ under the same light source. Use the pre-calibrated color correction matrix to convert the RGB response value of the unknown light source (hereinafter referred to as the test light source) in the actual scene to the XYZ color space, and use the CAT02 color adaptation transformation model to calculate its corresponding color under the reference light source. Color is the color perceived by the visual system of the observer after chromatic adaptation to the test light source.

Description

Technical field [0001] The invention relates to a method for adjusting the white balance correction result of a color digital camera by using a color adaptation model. The method can enable the color digital camera to achieve color reproduction more in line with human eye perception for a shooting scene. Background technique [0002] The same object often has different chromaticity parameters under different light sources. Due to the color constancy of the human visual system, these differences in chromaticity can be automatically compensated by the human eye and brain to a certain extent, so as to restore the "real" color of objects under different light sources. The white balance module in the image signal processing flow (ISP Pipeline) of color digital cameras, by calculating the difference between the chromaticity of the actual light source and the chromaticity of the standard light source, corrects the color cast phenomenon of the object under the non-standard light source, ...

AI Technical Summary

Problems solved by technology

[0004] If any lighting source, especially some light sources whose chromaticity deviates significantly from the reference white point, uses a unified reference light source as the target of white balance correction, the following disadvantages will occur to the image after white balance correction: 1) The output image is too " 2) The rendering effect of the light source on the scene atmosphere is completely suppressed; 3) Forcibly correcting the light source with serious color cast to the reference light source will increase the subsequent processing of the image signal processing process. Processing difficulty of modules (such as lens shading correction, color correction, etc.), which may even lead to image degradation

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