Histograms are generated for one or more of the image components. Each histogram is clipped at each end to exclude outlying values and to identify initial minimum and maximum values. Conservatism terms are included in each of the initial minimum and maximum values to generated final minimum and maximum values that are used as thresholds to define the color range used in chroma-key processing. In one embodiment, the first frame of a video sequence is designated as a chroma-key frame that is analyzed to determine the chroma-key color range.