Spectral colour calibration for multi-ink printer
Ying Wang, Zhongmin Wang, Sheping Zhai
School of Computer Science & Technology, Xi’an Univ. of Posts & Telecommunications, Xi’an, China
To implement colour calibration during outputting multispectral images on a multi-ink printer, a new spectral colour calibration method is proposed. Firstly, by uniform sampling in the multi-ink printer colour space, measuring the spectral reflectance of the samples and then transforming the reflectance data to a low dimension spectral space, a forward look-up table is created. Then by sampling in the low dimension spectral space and using a nonlinear optimization to calculate the mapping points of these samples in the printer colour space, a backward look-up table is established. Meanwhile, to improve the optimization accuracy and shorten the computing time, an algorithm is designed to determine the optimization parameters based the samples. Finally, a multi-linear interpolation method is carried out on the forward and backward look-up table to achieve the spectral colour calibration of the multi-ink printer. Experiments show that the new method not only takes advantage of the high calibration precision and less time-consuming of the look-up table, but also solves the problem brought by the high dimension of the spectral data to the look-up table method by utilizing the nonlinear optimization and dimension reduction. Compared with the spectral colour calibration model methods, the new method improves the colorimetric and spectral precision obviously. It also raises the time efficiency of the inverse calibration significantly.