Discrete cosine transform (DCT) implementation method and system based on randomized computation

The invention discloses a discrete cosine transform (DCT) implementation method and system based on randomized computation. The method comprises the following steps: mapping the ratio of an image transform unit (TU) to DCT into a decimal within a preset range, and transforming the decimal into a random sequence; transforming the random sequence into a randomized computation domain sequence, and computing by using a randomized computation multiplier and a randomized computation adder; transforming a computed result into a two's complement form in order to realize DCT. By adopting the method and the system, the hardware consumption can be lowered greatly, and the working clock frequency of the system is increased.