Research On Technology Of Spectral Color Calibration Based On Lookup Table

ICC color calibration tends to result in metameric color matching. The matched color in particular view condition will mismatch when the view condition is changed. In order to make the color of the samples consistent in different view conditions, the technology of spectral color calibration is proposed.The technology of spectral color calibration based on lookup table using an interim connection space (ICS) is researched in this dissertation. First, this dissertation contrasts two algorithms to conduct spectral color calibration. Second, this dissertation selects an algorithm called Sequential Quadratic Programming(SQP) that is used for inverse uniformity of high-dimensional interim connection space, points out its defect when it is used for inverse uniformity and then designs its objective function; Third, two methods are designed to reduce the large amount of data caused by the high-dimensional interim connection space. One is to decrease the dimensions of interim connection space and the other is to decrease the numbers of grids in each dimension of interim connection space; Fourth, on the basis of the spectral characteristics of the six-ink printer, to solve the problem that the one-to-many mapping between the spectrum and the ink of the six-ink printer results in inferior accuracy of color calibration and the problem that the iterative times of the Sequential Quadratic Programming method slow down the speed of setting up the lookup table, the selections of the initial value and the constraint for the Sequential Quadratic Programming method can improve these problems. Ultimately, the lookup table is set up and spectral color calibration is finished. Experiments indicate that the special selections of the initial value and the constraint can improve the accuracy of the color calibration and reduce iterative times of the Sequential Quadratic Programming method to increase the speed of setting up the lookup table.