Patent ID: 8320669

Claim:
An image processing method by which each small area including pixels within a color image is expressed by a predetermined or smaller number of representative colors, the method comprising: an obtaining step for obtaining values of individual color parameters for cyan, magenta, yellow, and black by which each pixel is expressed; a value calculation step for obtaining values of individual post-conversion color parameters from the values of the individual color parameters for cyan, magenta, yellow, and black, the values of the individual post-conversion color parameters each having a degree of variation being compensated to become smaller as the value of the color parameter for black becomes larger; a selection step for selecting one post-conversion color parameter to be targeted with respect to the pixels included in the small area based on variation values, which indicate degrees of variation in the small area, of the values of the individual post-conversion color parameters obtained in the value calculation step; a reference value calculation step for obtaining a reference value to be used for grouping the pixels based on the value of the post-conversion color parameter to be targeted in the small area; a grouping step for grouping the pixels included in the small area based on the reference value obtained in the reference value calculation step; and a representative color calculation step for obtaining a representative color for each group in the small area based on the values of the individual color parameters for pixels belonging to said each group.