Abstract: A color calibration procedure for use with a color raster scanner includes the steps of: identifying small areas on the source chart, or medium to be scanned, which contain only one color and assigning a color number to each area; positioning the scan head of the color raster scanner at two locations within the area identified and establishing the coordinate values for each of these two areas so as to bound by the coordinate definition the corners of a rectangular portion within the identified area; recording at each of a plurality of samples between the defined coordinates in each area the color samples resident therein; comparing the color samples of each color number obtained from each area with the samples obtained for each other color number of the other areas to determine the percentage of interference between colors and identifying the number of color samples which interfere with two or more colors as uncalibrated samples; and modifying the limits for a selected one of the spectral parameters associate

Abstract: A color identification circuit for use in identifying color samples received by a color raster scanner from a multicolor cartographic source chart includes a plurality of color limit comparators, one for each spectral parameter data channel of the sampled color element, each limit comparator including for each resident color on the source chart, the range of spectral values for the spectral parameter associated therewith, the range of values for each parameter representing the variations in the same color as obtained through color measurement samples taken from the source chart prior to actual data raster scanning; the output identification of a defined color spectral parameter from each limit comparator being presented to a color encoder, the color encoder identifying a unique color in dependence on the spectral parameter identification signals from each of the color limit comparators.