TY - RPRT
T1 - Lossless, Near-Lossless, and Refinement Coding of Bi-level
Images
AU - Martins, Bo
AU - Forchhammer, Søren Otto
PY - 1997
Y1 - 1997
N2 - We present general and unified algorithms for lossy/lossless
codingof bi-level images. The compression is realized by applying
arithmetic coding to conditional probabilities. As in the current
JBIG standard the conditioning may be specified by a template.For
better compression, the more general free tree may be used. Loss
may be introduced in a preprocess on the encoding side to increase
compression. The primary algorithm is a rate-distortion controlled
greedy flipping of pixels. Though being general, the algorithms
are primarily aimed at material containing halftoned images as a
supplement to the specialized soft pattern matching techniques
which work better for text. Template based refinement coding is
applied for lossy-to-lossless refinement.We demonstrate that both
single pass refinement coding and multiple pass refinement coding
yielding progressive build-up may be carried out very efficiently.
Introducing only a small amount of loss in halftoned test images,
compression is increased by up to a factor of four compared with
JBIG. Lossy, lossless, and refinement decoding speed and lossless
encoding speed are less than a factor of two slower than JBIG. The
(de)coding method is proposed as part of JBIG-2, an emerging
international standard for lossless/lossy compression of bi-level
images.
AB - We present general and unified algorithms for lossy/lossless
codingof bi-level images. The compression is realized by applying
arithmetic coding to conditional probabilities. As in the current
JBIG standard the conditioning may be specified by a template.For
better compression, the more general free tree may be used. Loss
may be introduced in a preprocess on the encoding side to increase
compression. The primary algorithm is a rate-distortion controlled
greedy flipping of pixels. Though being general, the algorithms
are primarily aimed at material containing halftoned images as a
supplement to the specialized soft pattern matching techniques
which work better for text. Template based refinement coding is
applied for lossy-to-lossless refinement.We demonstrate that both
single pass refinement coding and multiple pass refinement coding
yielding progressive build-up may be carried out very efficiently.
Introducing only a small amount of loss in halftoned test images,
compression is increased by up to a factor of four compared with
JBIG. Lossy, lossless, and refinement decoding speed and lossless
encoding speed are less than a factor of two slower than JBIG. The
(de)coding method is proposed as part of JBIG-2, an emerging
international standard for lossless/lossy compression of bi-level
images.
M3 - Report
BT - Lossless, Near-Lossless, and Refinement Coding of Bi-level
Images
ER -