The extraction system for color regions and their features has four stages: (1) transformation, quantization and filtering of the image, (2) back-projection of binary color sets onto the image, (3) region labeling and thresholding and (4) region feature extraction (see Figure 6). The goal of system is to reduce the color gamut and the insignificant color information in the image and emphasize the prominent color regions.
Figure 6: The color region and feature extraction system, T = color space transformation, 
color space vector quantization, BProj = back-projection, NL = non-linear filter, SL = sequential labeling, 
= thresholding and FE = feature extraction.