Progressive perceptually transparent coder for very high quality
images
Next: Perceptually Transparent Coding
Progressive perceptually transparent coder for very high quality
images
V. R. Algazi - G. E. Ford - R. R. Estes Jr. - A.
El-Fallah - A. Najmi
Abstract:
In the perceptually transparent coding of images, we use representation
and quantization strategies that exploit properties of human perception
to obtain an approximate digital image indistinguishable from the
original. This image is then encoded in an error free manner. The
resulting coders have better performance than error free coding for a
comparable quality. Further, by considering changes to images that do
not produce perceptible distortion, we identify image characteristics
onerous for the encoder, but perceptually unimportant. One such
characteristic is the typical noise level, often imperceptible,
encountered in still images. Thus, we consider adaptive noise removal to
improve coder performance, without perceptible degradation of quality.
In this paper, several elements contribute to coding efficiency while
preserving image quality: adaptive noise removal, additive decomposition
of the image with a high activity remainder, coarse quantization of the
remainder, progressive representation of the remainder, using bilinear or
directional interpolation methods, and efficient encoding of the sparse
remainder.
The overall coding performance improvement due to noise removal and the
use of a progressive code is about 18%, as compared to our previous
results for perceptually transparent coders. The compression ratio for a
set of nine test images is 3.72 for no perceptible loss of quality.
Next: Perceptually Transparent Coding
Robert Estes
Wed Sep 21 01:32:39 PDT 1994