Bulletin Spring‧Summer 1994

Dr. C.S. Choy (left) and Dr. W.K. Cham (middle) with their self-developed ASIC chips. Standing on the right is Dr. Raymond Yeung. Dr. W.K. Cham obtained his B.Sc. in electronics from CUHK in 1979, and his Ph.D. from Loughborough University of Technology, UK in 1983. He returned to the Department of Electronic Engineering as lecturer in 1985, becoming senior lecturer in 1992. Dr. C.S. Choy obtained his B.Sc. and Ph.D. from Manchester University in 1983 and 1987 respectively. He joined the Department of Electronic Engineering as an assistant lecturer in 1986 and was promoted to lecturer in 1987. can rearrange the arithmetic so that nearly all the multiplications required can be reduced effectively to multiplication by 2 or 4, something which the computer on board the Galileo can easily handle. Dr. Cham, together with another colleague Dr. Raymond Yeung of the Department of Information Engineering, was invited to join the team of consultants at the Jet Propulsion Laboratory, NASA, for the Galileo project in mid-1993 ， and submitted his research report to the laboratory earlier this year. Dr. Cham's reseach findings also make image compression on earth that much easier. Using integer cosine transforms, one can achieve a compression ratio of 20. Fig. 2a shows an untreated image. Fig. 2b is the corresponding image recovered after compression by a factor of 20. Specialist CPUs Given the importance of cosine transform in image coding and Dr. Cham's contribution to a much improved algorithm, it becomes a logical and natural step to study how computer hardware can facilitate and speed up ICTs. The objective is to design Application Specific Integrated Circuits (ASIC) that can perform ICT calculations very fast. In this task, Dr. Cham teamed up with Dr. C.S. Choy, a colleague in the Department of Electronic Engineering. They have now developed and fabricated an ASIC chip which can compute nearly a million ICTs every second. They have also designed and fabricated a data sequencer chip which is to be used with the ICT chip to transform the pixels of a TV picture twice — once in the horizontal direction and once in the vertical direction. I f one has a factor of 4 compression in each direction, the overall result will be a factor of 16. This is called a two-dimensional transform, and is used in international standards such as H.261, JPEG, MPEG1 and MPEG2. Most recently, Dr. Choy and Dr. Cham have designed a single chip that integrates the ICT and data sequencer functions, doing the two-dimensional transform in one step. New design techniques and faster chips are the next tasks to be tackled. With these new inventions, one can look forward to better planetary photos, better TV pictures, and cheaper video phones. Fig. 2a Fig. 2b Research Projects 10