Open AccessSelecting the don't care bits in JPEG2000 ROI coding
Author(s) -
Jamshid Ameli,
J. Vaisey,
Tong Jin
Publication year - 2004
Publication title -
proceedings of spie, the international society for optical engineering/proceedings of spie
Language(s) - English
Resource type - Conference proceedings
SCImago Journal Rank - 0.192
H-Index - 176
eISSN - 1996-756X
pISSN - 0277-786X
DOI - 10.1117/12.529453
Subject(s) - jpeg 2000 , computer science , bit plane , encoder , coding (social sciences) , bitstream , variable length code , entropy encoding , algorithm , transform coding , entropy (arrow of time) , decoding methods , image compression , bit field , computer vision , image processing , mathematics , discrete cosine transform , image (mathematics) , mechanical engineering , drilling , statistics , engineering , operating system , physics , quantum mechanics
Region of interest coding is an important feature in JPEG2000 and it is accomplished by pre-emphasizing the wavelet coefficients participating in the reconstruction of the ROI. In the general scaling-based method, a number of extra bits appear in the right side of the least significant bit of the ROI samples after the shifting process. These bits need be coded at the time of bit-plane coding, but they are discarded by the decoder. The usual procedure is for the encoder to set these "don't care" bits to zero. In this paper, we propose a method that exploits the state of the JPEG2000 entropy coder to set the values of these bits in a more intelligent way. The method can be implemented with only a small increase in coder complexity and improvements of up to 6% in the number of bits required to represent a code-block has been observed. The bit-stream remains JPEG2000 compliant.
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