Research On LED Color Gamut Transformation Based On Polynomial Regression And Approximation

Chroma parameters of XYZ should be acquired before calibration to LED display.There are two kinds of existing chroma collecting devices: point collection device andsurface collection device. Point collection device is inexpensive, being simple tooperate, but it can not be mass collecting. Surface collection device can be masscollecting, but it is very expensive and not easy to operate. One of the commonchroma collection devices is CCD prototype. It can collect data of RGB color gamutof LED pixels. Its tristimulus values are different from human·s vision. They shouldbe changed to a device independent color gamut, for example, XYZ. This paperproposes a color gamut transformation technology of LED based on polynomialregression and approximation. Using this method can transform the acquired RGBdata of color CCD prototype to CIE standard XYZ color gamut data. Chromacollection can be finished consequently. It is not expensive, easy to operate. It canaccomplish collecting of color gamut in mass surface and give consideration toadvantages of point collecting device and surface device. It is a convenient andeffective color gamut collecting method.Full text can be mainly devided into three parts:At first, related contents on collection of sample data for color gamuttransformation are introduced, include: curved surface modification and noisereduction for color CCD prototype, location and recognition of LED pixels, extraction of sample·s color gamut data in RGB and XYZ. It can provide data for color gamuttransformation.Secondly, LED display·s color gamut is transformed using method of polynomialregression and approximation. The relationships between spectral response curve ofCCD prototype, tristimulus of CIE XYZ and curve of spectrum of LED are analysed.Characterized convergence factors of the matrix can be obtained. Then polynomialmethod in target color analysis methods should be used to find out the multinomialcoefficients in best situation of matching when sample LED pixels· values of RGBand XYZ are substituted. Minimum error is counted out. Transfer matrix of red, greenand blue from RGB to XYZ of LED display is acquired consequently.At last, in order to test and verify validity of transformation, chromatic aberration,photos before calibration and after calibration are given out. Furthermore,comparisons between polynomial regression method and neural network method andLUT method are made. Accuracy and validity of this method is tested and verified.Color gamut transformation technology of LED base on polynomial regressionand approximation sets up the relationship between color gamut of RGB and XYZand then accomplish the collection of chroma. The research result of this paper opensup the precedent that only using CCD prototype to collect LED display·s chroma andcalibrate the LED display. It is valuable both in theory and in practice. It lays a solidfoundation for theoretical basis and practical experience for future.