In this section, we will demonstrate how to perform a pixel-wise Vector Quantization (VQ) of the pepper image, reducing the number of colors required to show the image from 250 unique colors down to four colors, while preserving the overall appearance quality. In this example, pixels are represented in a 3D space and k-means is used to find four color clusters.
In image processing literature, the codebook is obtained from k-means (the cluster centers) and is called the color palette. In a color palette, using a single byte, up to 256 colors can be addressed, whereas an RGB encoding requires 3 bytes per pixel. The GIF file format uses such a palette. For comparison, we will ...
