TY - JOUR
T1 - Optimisation of multi-level block truncation coding
AU - Chan, K. W.
AU - Chan, K. L.
PY - 2001/1
Y1 - 2001/1
N2 - Block truncation coding (BTC) is very attractive for real-time image coding at moderate bit-rate due to its low computation and storage demands. One major artefact of this image compression technique is edge raggedness. Modifications are mainly in two areas: bit-rate reduction and improvement of the quality of reconstructed image. Our investigation is in the latter area. In our integrated multi-level BTC scheme, the visual quality is substantially improved, the bit-rate is maintained the same as standard BTC and the computational demand is still kept low. We exploit various algorithms and derive new techniques to optimise the performance of multi-level BTC. Dynamic range tuning (DRT) is used to tackle 2-level BTC. Middle group settlement is used to carry out binary classification for tri-modal distribution. For 4-level BTC, an iterative DRT is derived. Based on our experience on 2- and 4-level BTCs, an optimised 3-level BTC is derived. Extensive testing has been carried out on 30 images. The resultant visual quality is nearly perfect and the PSNR may be boasted by up to 7 dB. © 2001 Elsevier Science B.V. All rights reserved.
AB - Block truncation coding (BTC) is very attractive for real-time image coding at moderate bit-rate due to its low computation and storage demands. One major artefact of this image compression technique is edge raggedness. Modifications are mainly in two areas: bit-rate reduction and improvement of the quality of reconstructed image. Our investigation is in the latter area. In our integrated multi-level BTC scheme, the visual quality is substantially improved, the bit-rate is maintained the same as standard BTC and the computational demand is still kept low. We exploit various algorithms and derive new techniques to optimise the performance of multi-level BTC. Dynamic range tuning (DRT) is used to tackle 2-level BTC. Middle group settlement is used to carry out binary classification for tri-modal distribution. For 4-level BTC, an iterative DRT is derived. Based on our experience on 2- and 4-level BTCs, an optimised 3-level BTC is derived. Extensive testing has been carried out on 30 images. The resultant visual quality is nearly perfect and the PSNR may be boasted by up to 7 dB. © 2001 Elsevier Science B.V. All rights reserved.
KW - Block truncation coding
KW - Image compression
KW - Multi-level quantization
UR - http://www.scopus.com/inward/record.url?scp=0035095497&partnerID=8YFLogxK
UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-0035095497&origin=recordpage
U2 - 10.1016/S0923-5965(00)00009-6
DO - 10.1016/S0923-5965(00)00009-6
M3 - RGC 21 - Publication in refereed journal
SN - 0923-5965
VL - 16
SP - 445
EP - 459
JO - Signal Processing: Image Communication
JF - Signal Processing: Image Communication
IS - 5
ER -