We describe experimental tests of a spatial extension to the CIELAB color metric for measuring color reproduction errors of digital images. The standard CIELAB /spl Delta/E metric is suitable for use on large uniform color targets, but not on images, because color sensitivity changes as a function of spatial pattern. The S-CIELAB extension includes a spatial processing step, prior to the CIELAB /spl Delta/E calculation, so that the results correspond better to color difference perception by the human eye. The S-CIELAB metric was used to predict texture visibility of printed halftone patterns. The results correlate with perceptual data better than standard CIELAB and point the way to various improvements.
['Xuemei Zhang', 'D.A. Silverstein', 'Joyce E. Farrell', 'Brian A. Wandell']
Color image quality metric S-CIELAB and its application on halftone texture visibility