DSP-based automatic color reduction using multiscale clustering
Hyuk-Joon Oh, Nasser Kehtarnavaz · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2001
This paper presents a modification of the multi-scale clustering algorithm in order to reduce the color content of an image in an automatic manner without requiring the specification of the number of colors. The clustering space is chosen to be the YCbCr color space as used in the JPEG compression standard. Although multi-scale clustering is capable of defining prominent data clusters in an automatic manner, it may not generate all perceptibly distinctive colors when applied to the YCbCr color space. In this work, we have modified the multi-scale clustering algorithm to overcome this limitation for color reduction purposes. Our color reduction algorithm consists of two parts. The first part is a modification of multi-scale clustering to obtain a set of primary color prototypes. The second part is a color sectoring method to obtain a set of secondary color prototypes. The developed color reduction algorithm has been implemented on a high performance DSP processor, namely TMS320C6201, due to the computational requirement associated with multi-scale clustering. The result show on average 50 percent more compression over that of the JPEG standard for the color portion of images with comparable levels of color distortion.