H. Yuen

Graphical Communications

Our current research interests are handwriting encoding, handwriting/signature recognition/verification, multimedia image coding and wireless transmission of handwriting signals.

Handwriting signals can be captured by an electronic writing tablet with a writing pen. The tablet produces the (x,y) coordinates of the pen-tip when the pen is in writing. There are different approaches for handwriting encoding. Chain coding is efficient for encoding two-dimensional planar curves and usually requires spatial re-sampling when encoding handwriting signal. On the other hand, coding schemes such as zone coding can be used to directly encode the handwriting signal without spatial re-sampling.

So far, we have developed 3 new coding schemes for handwriting encoding: Delta Modulation-like differential chain coding (DM-DCC), Fixed-length differential chain coding (FL-DCC) and Lossless Generalized Chain Coding (GCC). DM-DCC and FL-DCC are lossy differential chain coding (DCC) schemes with reduced bit rate. Lossless GCC is a direct encoding scheme similar to zone coding except it is based on chain coding.

We have six DOS "*.exe" files which implement the various coding schemes: DM-DCC, FL-DCC, DCC, SCC, zone coding and lossless GCC. You can run these programs in DOS to evaluate the different coding results such as decoded graphical quality and bit rate. When running the programs, remember to have "egavga.bgi" driver in the same directory.

To download these programs click here.

Please refer to our papers for further details.

Our publications on chain coding:

  1. H. Yuen, "A chain coding approach for real-time recognition of on-line handwritten characters", ICASSP'96, Atlanta, USA, 1996.
    Abstract - Lossless GCC coding scheme is proposed for directly encoding the coordinate differences from a writing tablet.

  2. H. Yuen, "DM-like differential chain codes for handwriting and line graphics", to appear in IEE Proceedings-Vision, Image and Signal Proceesing April 1996. pp.96-100.
    Abstract - DM-DCC coding scheme is proposed, which offers the lowest bit rate at the expense of increased quantisation distortion.

  3. H. Yuen and L. Hanzo, "Adaptive fixed-length differential chain coding for transmission of line graphics", Electronics Letters, Vol 31, No 11, May 1995, pp. 862-863.
    Abstract - An adaptively defined fixed-length differential chain coding scheme is proposed, which offers better error performance, a reduced bit rate and a more uniform data syntax than the differential chain coding (DCC) scheme.

  4. H. Yuen and L. Hanzo, "Robust differential chain coding scheme", Electronics Letters, Vol 31, No 16, August 1995 pp. 1334-1335.
    Abstract - The error sensitivity problem in the relative vectors of DCC scheme is addressed. An error robust technique is proposed, which combines the error-resistant absolute vectors with the bandwidth-efficient relative vectors, without increasing the relative vector's bandwidth.

  5. H. Yuen and L. Hanzo, "A new coding scheme for transmission of on-line handwriting", IEEE 1995 Global Telecommunications Conference, GLOBECOM'95, Nov. 1995, Singapore, pp. 2284-2288.

  6. H. Yuen and L. Hanzo, "Wireless multi-level graphical correspondence", IEEE International Conference on Universal Personal Communications, ICUPC'95, Nov. 1995, Tokyo, Japan, pp. 17-21.

  7. H. Yuen and L. Hanzo, "New chain coding scheme for cursive script and line drawings", Third International Computer Science Conference on Image Analysis Applications and Computer Graphics", ICSC'95, Dec. 1995, Hong Kong, pp. 233-240.

Department of Electronics & Computer Science,
University of Southampton,
Highfield, Southampton SO17 1BJ
Telephone: (01703) 592422
FAX: (01703) 592865
Email: enhyuen@hkpu01.polyu.edu.hk --OR-- hy94r@ecs.soton.ac.uk