基于色域范围划分的印刷黑版生成算法

Black Generation Algorithm for Printing Reproduction Based on Gamut-Range Division

为解决胞元纽介堡反向颜色转换中的黑版控制问题,本研究提出了一种基于色域范围划分的黑版生成算法。该方法采用阶调分段式处理,通过特定设计的色标打印,获取不同黑版条件下的色域范围;然后判别输入颜色所在的色域组范围,以确定其K值取值范围。在取值范围内,根据图像阶调和颜色特征设定最佳黑版量,以此代入纽介堡方程计算唯一解。色差评价结果显示:在各种不同的黑版替代率条件下,K值色域检索算法所产生的均值色差范围都明显低于2个标准色差单位,且与主流色彩管理软件i1 Profiler相差低于1个色差单位;最大均值色差稍大1~2个色差单位。图像测试结果表明,本研究算法较好地再现了图像暗调部位细节,可以满足印刷工业图像复制要求。

In order to solve the problem of black control in the reverse color conversign of cellular Neugebauer model,a black generation algorithm based on the gamut range division was proposed in this study.First,the gamut ranges under different black conditions were obtained by printing the color target especially designed.Then,the black value range was determined by obtaining the gamut group which the input color was belong to.On this basis the optimal black value was determined according to the tone and color characteristics of the image,and then the unique solution was calculated by inputting the optimal black value into the reverse Neugeberg equation.The experimental results showed color difference range caused by the new algorithm was significantly lower than 2 standard color difference units(based on CIEDE2000 Equation)under the conditions of different black replacement rates.Compared with the commercial color management software i1 Profiler,the mean color difference of the new algorithm was only less than about 1 color difference unit,and the maximum mean color difference was slightly larger by 1-2 color difference units.The results of image quality evaluation showed that the new algorithm can reproduce the details of the dark part of the image well and meet the requirements of the printing industry for image reproduction.