采用查找表的超四色打印光谱色彩校正方法

Spectral color calibration method for the multi-ink printer using the look-up table

为解决多光谱图像打印输出时的色彩校正问题,提出一种采用查找表进行打印光谱色彩校正的方法.首先在超四色打印机色空间规则采样并测量采样点的光谱值,将光谱值变换至一个低维空间,建立正向查找表;然后在低维光谱空间中采样,运用非线性优化技术确定采样点在打印机色空间中的映射点,根据采样点确定优化参数来提高优化精度和时间效率,建立反向查找表;最后采用高维线性插值方法,在正向和反向查找表中插值以实现打印光谱色彩校正.实验结果表明,在相同的仿真环境下,新方法与常用的建立光谱打印色彩校正模型法相比,在正向校正的色度精度和光谱精度上分别提高了40%和44%,在反向校正精度上分别提高了51%及41%,且反向校正的时间效率提高了96%.

To achieve the color calibration in the multi-spectral image print output, a new calibration method for the multi-ink printer is proposed. By sampling in the multi-ink print color space, measuring the spectral reflectance of the samples and then transforming the reflectance data to a low-dimensional spectral space, a forward look-up table is established firstly. Then by sampling in the low-dimensional spectral space and using the nonlinear optimization to determine the mapping points of the samples in the printer color space, a backward look-up table is created. Meanwhile, optimization parameters are determined according to the samples, which improves the optimization accuracy and shortens the computing time. Finally a multi-linear interpolation method is carried out on the forward and backward look-up table to achieve the spectral color calibration of the multi-ink printer. Experiments show that compared with the spectral color calibration model methods, the new method increases the colorimetric and spectral precision by 40% and 44%, respectively, in forward calibration, and 51% and 41% in backward calibration. The time efficiency is improved by 96% in backward calibration.