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NAME

tceencode, tcedecode - encode/decode an image using the TCE algorithm

SYNOPSIS

tceencode [-w wavelet] [-b boundary] [-nl levels] [-ss stepsize] [-r rate] [-vo] imgfile bitstream

tcedecode [-w wavelet] [-b boundary] [-r rate] bitstream imgfile

OPTIONS

-w wavelet
String. Name of the wavelet file (FBK or LFT format); default = "CohenDaubechiesFeauveau.9-7.lft"
-b boundary
String. Type of boundary extension; default = "symmetric".
-nl levels
Integer. Number of levels of dyadic decomposition; default value is 5 levels.
-ss stepsize
Float. The initial quantization stepsize; if this option is specified, the coder will encode until all bitplanes of the quantized coefficients are encoded.
-r rate
Float. The target encode/decode bit rate.
-vo
Print only the value of the rate to stdout (terse output); default is verbose output.

DESCRIPTION

tceencode codes an image, imgfile, using the TCE algorithm by Tian and Hemami. The TCE (tarp coding using classification to achieve embedding) algorithm is based on the tarp algorithm (see QccWAVTarpEncode(3) ), but is designed to provide better rate-distortion performance when used in an embedded fashion; i.e., when decoding is performed at a rate less than that at which the bitstream was produced. See QccWAVtceEncode(3) for more detail on the TCE algorithm.

The transform is the usual discrete wavelet transform (DWT), with the -w option specifying the wavelet, and the -b option specifying the boundary extension.

tceencode supports two encoding modes. Mode 1 consists of first applying a scalar quantizer to all DWT coefficients and then encoding the coefficients, bitplane by bitplane, until all bitplanes are encoded. Mode 2 consists of direct bitplane encoding without any scalar quantization of coefficients; in this mode, encoding stops when the target bitrate is reached. Mode 1 is selected by specifying a quantization stepsize with the -ss option. Mode 2 is selected by specifying a target encoding rate with the -r option. Note that one, and only one, of -ss and -r must be specified.

tceencode prints to stdout a small amount of information concerning the target bitrate and the actual bitrate achieved, as well as some run time information. Usually these rates are identical, but may differ slightly. If the -vo (value-only) option is given, all printed output is suppressed except for the actual bitrate.

tcedecode performs the corresponding decoding using the TCE algorithm, decoding the bitstream made by tceencode and producing a reconstructed image, imgfile. For sane results, wavelet and boundary should be the same as they were for tceencode. The -r option for tcedecode specifies the rate at which to stop decoding, which may be any rate less than that at which bitstream was originally produced.

tceencode and tcedecode call QccWAVtceEncode(3) and QccWAVtceDecode(3) , respectively, to perform TCE encoding and decoding. Refer to the man pages for these functions for more information on the details of the QccPack implementation of the TCE algorithm.

SEE ALSO

QccWAVtceEncode(3) , QccWAVtceDecode(3) , QccWAVTarpEncode(3) , QccWAVTarpDecode(3) , imgdwt(1) , QccWAVSubbandPyramid(3) , QccPackWAV(3) , QccPackIMG(3) , QccPack(3)

C. Tian and S. S. Hemami, "An Embedded Image Coding System Based on Tarp Filter with Classification," in Proceedings of the International Conference on Acoustics, Speech, and Signal Processing, Montreal, Quebec, Canada, May 2004, vol. 3, pp. 49-52.

AUTHOR

Written by Chao Tian, Cornell University

Copyright (C) 1997-2021 James E. Fowler


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