IMAGE-CODING THROUGH PROGRESSIVE RESOLUTION TRANSFORMS

Visual information must be represented digitally to allow its processing by computer. This representation by means of a finite amount of digital data conveys an enormous amount of superfluous information that can be eliminated. We can consider two kinds of superfluous information: statistical redundant and subjective redundant. Discrete transform coding takes blocks of pixels and transforms them into another domain, the transform domain, prior to coding and transmission. An important property is that coefficients need not to be transmitted all in order to obtain good-quality reconstructions. We have applied a special nonorthogonal transform in order to compress radiographic images.