Transform-coding of images with reduced complexity

Image Segmentation Using Human Visual System Properties With Applications In Image Compression

“…A disadvantage to transform coding is the number of computations required to perform the image pixel transformation. For this reason, fast transform algorithms have been developed and are often used for transform image coding [67,71,72]. Also, transform compression algorithms are nearly always implemented on a block-wise basis to help reduce the computation time required [24].…”

Fast algorithms for the real discrete Fourier transform

“…When the other discrete trigonometric transforms are expressed in terms of the RDFT, the best fast algorithms for the RDFT also correspond to the best fast algo rithms for the other transforms in terms of the number of operations [7]. The scram bled RDFT (SRDFT) gives basically the same performance in image compression as the discrete cosine transform (DCT) with much fewer number of operations [8]. A number of claims such as Walsh-filtering being more efficient than Fourier-filtering can be shown to be untrue once the RDFT is utilized [8j.…”