Quantization is originally defined as the digitization of a continuous signal. The signal may represent a monochromatic tone varying between black and white, and may be measured by its intensity. The task of quantization is to map the signal’s intensity values into a series of gray levels (e.g., 256 levels from black to white along the gray axis). The signal may also carry chromatic information with multiple attributes that characterize the signal within a multidimensional color space (e.g., c = (r, g, b) for the red, green, and blue [RGB] space). In this case, quantization amounts to mapping color points onto a grid that discretizes the color space (e.g., 256 levels in each dimension).