Implementation Of Fast Cosine Transforms With Digital Signal Processors For Image Compression
Kelby K. Chan · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1988
The use of the discrete cosine transform (DCT) in imaging applications is still not as extensive as it's properties would imply, due to a comparative lack of available hardware for fast computation. Commercially available image processors typically implement the Fourier transform, and most do not have the word size necessary to handle the wide dynamic range required for radiological images with up to 2K x 2K size and 8 or more bits resolution. Efficient and easy to implement algorithms exist for the computation of the DCT. The advent of programmable single chip digital signal processors (DSP's) with fast multiplier-accumulator (MAC) units and large word sizes (24 to 32 bits) allow for hardware solutions that are economical, fast, and flexible. A special module utilizing multiple DSP's for performing the fast cosine transform (FCT) for image compression has been built. The flexibility afforded by DSP programming allows for handling of input data with different formats, dynamical scaling, and any necessary pre- or post-processing operations.