Scanner characterization for color measurement and diagnostics

bstract. We propose a novel scanner characterization approach or applications requiring color measurement of hardcopy output in alibration, characterization, and diagnostics applications. The ethod is advantageous for common practical color printing sysems that use more than the minimum of three colorants necessary or subtractive color reproduction; printing with cyan (C), magenta M), yellow (Y), and black (K) is the most prevalent example we use n our description. The proposed method exploits the fact that for the cenarios in consideration, in addition to the scanner RGB values or a scanned patch, the CMYK control values used to print the atch are also available and can be exploited in characterization. An ndexed family of 3D scanner characterizations is created, each haracterization providing a mapping from scanner RGB to CIELAB or a fixed value of K, the latter constituting the index for the charcterization. Combined together, the family of 3D characterizations rovides a single 4D characterization that maps scanner RGB obained from scanning a patch and the K control value used for printng the patch to a colorimetric CIELAB measurement for the patch. A ignificant improvement in the robustness of the method to variaions in printing is obtained by modifying the K index to utilize the canned output for a black-only patch printed with the correspondng K value instead of directly utilizing the control K value used at he printer. Results show that the proposed 4D scanner characterzation technique can significantly outperform standard 3D aproaches in the target applications. © 2007 SPIE and IS&T. DOI: 10.1117/1.2803833