Color image quality metric S-CIELAB and its application on halftone texture visibility

We describe experimental tests of a spatial extension to the CIELAB color metric for measuring color reproduction errors of digital images. The standard CIELAB AE metric is suitable for use on large uniform color targets, but not on images, because color sensitiviq changes as a function of spatial pattern. The S-CIELAB extension includes a spatial processing step, prior to the CIELAB AE calculation, so that the results correspond better to color difference perception by the human eye. The S-CIELAB metric was used to predict texture visibil-it): of printed halftone patterns. The results correlate with perceptual data better than starzdard CIELAB arzd poirlt the way to various improvements. 1