CORAL: COLLECTIVE RATIONALITY FOR THE ALLOCATION OF BITS

CORAL: COLLECTIVE RATIONALITY FOR THE ALLOCATION OF BITS

(Version: 1.0: CORAL.HTML v. 1.0 2002/10/4)

Table of Contents

Introduction

CORAL is a software-based implementation of the codec specified in the paper "CORAL: Collective rationality for the allocation of bits"by J.A Garcia et al..
The CORAL scheme in absence of a priori knowledge about regions of interest propose a new method for bit allocation which can be used with reasonable internal consistency and acceptable image fidelity. The CORAL scheme exploits a space-varying filterbank tree representation of the image by applying a novel solution to the problem of bit allocation among subimages: Each may benefit only on terms which permit proportionately equal benefits to others.It is applicable in realist settings where images may have locally varying space-frequency characteristics and without assumptions about the subband or transform coding that is to be used to decompose the image into several regions and how the regions are quantized individually.
The CORAL scheme is firstly based on the principles of competitive rationality to achieve the pre-agreement position and secondly in a general procedure for cooperative action that takes into account the relative magnitude of the utility loss that each region suffers at a particular allocation
The CORAL software is written in the C programming language. This language was chosen mainly due to the availability of C development enviroments for most of today's computing platforms. There are two executable programs, encoder program, and decoder program.The CORAL software handles image data in PGM format. The coding scheme was not optimized by entropy-coding the output, and thus, the bitstreams (put out with the coding algorithm) are binary uncoded (without entropy coding).

Examples

The next sentences show how to use the commands coral and uncoral on the barbara image ( a 512x512 graylevels pgm image). (r = 0.25 is equivalent to a ratio of 32:1)

The following examples show images encoded/decoded using (with entropy coding )JPEG 2000 (The JASPER Project Home Page.) and (without entropy coding) CORAL.The images are decomposed by a 6-level 9-7 tap biorthogonal Daubechies filter.


Computation Times

The computational time (in seconds) after running CORAL for different images is showed in the next table. CORAL was run on a 1.70 GHz Pentium IV under LINUX operating system.
Computational time (in seconds) for CORAL
IMAGE
Rate (bpp)
TIME
SEAPORT
1
56
0.5
56
0.25
56
0.125
23
TEIDE
1
59
0.5
56
0.25
56
0.125
23
BUTFISH1
1
60
0.5
60
0.25
57
0.125
24

Related links

Copyright

These programs are Copyright (c) 2002 by Rosa Rodriguez-Sanchez et al. They may not be redistributed without the consent of the copyright holders. In no circumstances may the copyright notice be removed. Permission to use, copy, or modify this software and its documentation for educational and research purposes only and without fee is hereby granted, provided that this copyright notice and the original authors' names appear on all copies and supporting documentation. For any other uses of this software, in original or modified form, including but not limited to distribution in whole or in part, specific prior permission must be obtained from the authors. These programs shall not be used, rewritten, or adapted as the basis of a commercial software or hardware product without first obtaining appropriate licenses from authors. Each program is provided as is, without any express or implied warranty, without even the warranty of fitness for a particular purpose.