Point-and-click region based method for color editing and control for digital color printers

To meet ever changing customer demand, the commercial printing industry requires the capability of producing colors accurately and consistently. In this presentation, we propose to use a region growing process with a spatial (i.e., 2-D) color gradient matrix in RGB or L*a*b* or CMYK space to pick a region/object of interest. A grid with Laplacian edge map is constructed for the whole image a priori using the spatial color gradient matrix. The Laplacian edge map (a template), if needed, is shown on the GUI to guide the user to point at his or her object of interest. After clicking the mouse, the algorithm will grow the region until it coincides with the Laplacian edge map. A color constrained cost function is introduced to prevent leakage through mild transitions between different objects. Once the object is selected, a customized rendering LUT is applied to improve the color quality of the object. We also present control-based techniques to create inverse transformation that produce more accurate CMYK values. Control based techniques minimize the rendering errors normally occur during inversion and gamut mapping process.