Digital Signal Processing/Discrete Cosine Transform

Discrete Cosine Transform in dsp
The Discrete Cosine Transform (DCT) is a transform that is very common when encoding video and audio tracks on computers. Many "codecs" for movies rely on DCT concepts for compressing and encoding video files. The DCT can also be used to analyze the spectral components of images as well. The DCT is very similar to the DFT, except the output values are all real numbers, and the output vector is approximately twice as long as the DFT output. It expresses a sequence of finite data points in terms of sum of cosine functions.

Uses of DCT
The JPEG process is a widely used form of lossy image compression that centers around the Discrete Cosine Transform. The DCT works by separating images into parts of differing frequencies.