Pn. Nicholl et Rj. Millar, FEATURE-DIRECTED SPIRAL CODING OF MAGNETIC-RESONANCE IMAGES, IEE proceedings. Vision, image and signal processing, 145(2), 1998, pp. 131-136
The authors investigate the encoding of magnetic resonance (MR) images
of the human body using various lossless techniques, and presents a n
ew form of spiral encoding. The algorithm used relies partially on the
overall shape of the bounding contour of the image in achieving the c
ompression and uses a traditional run-based technique combined with an
adaptive Huffman coder to encode the complete image. Comparisons are
made between the feature-directed spiral encoding and the traditional
paths; the latter include the scanning pattern associated with the nor
mal raster scanned display and the path for a display that could be us
ed in following a linearised quadtree encoding. The new method tracks
the 'greater' contour of the overall image and, once the path has been
established and tuples recorded. the inner contours are automatically
generated. The process is repeated for each of the inner contours wit
h a reducing radius towards the centre. The results are given for the
various techniques in terms of compression ratios. The new spiralling
method achieves an approximate 5.29% saving over the traditional techn
iques and also gives structure to the compressed image.