Abstract: A method of compressing an image frame composed of an array of pixels in the form of digital signals comprises a two stage codebook search. In the first stage the pixelated image frame and the pixelated codebook patches are transformed to frequency domain coefficients and a pattern comparison is made between the coefficients of the image patch and the codebook patches to identify a short list of possible match codebook patches by discarding incorrectly matching patterns. In the second stage the image frame is compared with the short list of codebook patches by any desired method, e.g. by pixel comparisons, to select the best matching codebook patch.

Abstract: A method of compressing an image frame composed of an array of pixels in the form of digital signals comprises a two stage codebook search. In the first stage the pixelated image frame and the pixelated codebook patches are transformed to frequency domain coefficients and a pattern comparison is made between the coefficients of the image patch and the codebook patches to identify a short list of possible match codebook patches by discarding incorrectly matching patterns. In the second stage the image frame is compared with the short list of codebook patches by any desired method, e.g. by pixel comparisons, to select the best matching codebook patch.

Abstract: A recognition system of the self-organizing artificial neural network type is arranged to classify input data according to stored categories which have been determined by a training process. In the training process the initial category representations are selectively iteratively updated in response to a series of training patterns and in accordance with a competitive learning routine. this routine uses measures of category utilization based on the proportion of all inputs received over a representative period, particularly long term utilisation and short term utilization, to ensure that all available categories will be used and that the system is stable. The training rate which determines the amount of modification to a category representation at an up-date is local to each category and is based upon the maturity of the category and on the similarity measure between the internal representative pattern and the training input so that the training duration can be minimized.

Abstract: A method of compressing an image frame composed of an array of pixels in the form of digital electrical signals, the method comprising the steps of: (a) providing a reference image as a first approximation to the original image to be compressed; (b) dividing the original image into patches of one or more sizes; (c) for each patch determining a compressed encoding of the data contained therein where the compressed encoding can be uncompressed to provide an approximation to the patch; (d) selecting that one of the compressed encodings which, when uncompressed and added to the reference image, gives the biggest improvement therein relative to the original image; (e) adding the selected compressed encoding in uncompressed form to the reference image and in compressed form to a compressed representation of the original image; and (f) recursively repeating step (d) for the remaining compressed encodings until either a desired quality level of the reference image or a maximum data size of the compressed representati