Introduction

Transform coding is an integral component of image and video processing applications. The main goal is to map a set of pixel values into a few transform coefficients with certain desired properties. The mapping process, or transform, must fulfill two important features: The coefficients in the transform domain should be decorrelated and the total energy must be conveyed by only a few coefficients with the remaining coefficients carrying insignificant energy. A number of transformation techniques exist that fulfill the above properties, although their energy packing capabilities vary. Sinusoidal transforms, like the discrete cosine transforms and discrete Fourier transforms use image-independent transformations. The discrete cosine transform is preferred over the Karhunen–Loeve transform because it is separable, real, orthogonal and has a fast algorithm.