MR image compression by spiral coding

Investigates the encoding of magnetic resonance (MR) images of the human brain using various lossless techniques and presents a new form of spiral encoding. The algorithm used relies partially on the overall shape of the bounding contour of the image in achieving the compression and uses a traditional run-based technique to generate a set of tuples for a complete image. Comparisons are made between the feature-directed spiral encoding and the traditional paths; they include the scanning pattern associated with the normal raster scanned display and the path for a display that could be used in following a linearised quadtree encoding. The new method tracks the `greater´ contour of the overall image and once this path has been established and tuples recorded, then the inner contours are generated. From the one greater contour each of the inner contours, with a reducing radius towards the centre, can be created. The results for various techniques in terms of the number of bytes required to store the image are given. The new spiralling method achieves an average compression ratio of 1.49 for the set of MR images