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From: paul@neopath.com (Paul Wilhelm)
Subject: Re: What is HADAMARD and DCT
Message-ID: <1994Oct24.203553.6241@neopath.com>
Followup-To: paul@neopath.com
Keywords: Image compression
Sender: paul@neopath.com
Organization: NeoPath Inc.
References: <1994Oct20.153302.18964@lorienne.oleane.com>
Date: Mon, 24 Oct 1994 20:35:53 GMT
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Xref: glinda.oz.cs.cmu.edu comp.graphics.algorithms:9549 sci.image.processing:10524

In article <1994Oct20.153302.18964@lorienne.oleane.com> malaingr@lorienne.oleane.com (Herve Malaingre) writes:
>Could somebody tell to me where I can find the description or better  
>sources files of (for my brither who is a student in a french university)  
>the HADAMARD and Discret Cosine Transform algorithms.
>
>Thanks
>
>Herve MALAINGRE
>Director of Sales

The Hadamard Transform is described in (see top of page 1249):

Shu Yuan and Kai-bor Yu, "Zonal Sampling and Bit Allocation of HT Coefficients
in Image Data Compression," IEEE Transactions on Communications, Vol. Com-34,
No. 12, Dec 1986.


The Discrete Cosine Transform is described in:

N. Ahmed, et.al, "Discrete Cosine Transform," IEEE Transactions on Computers,
Jan. 1974.

M. J. Narasimha, et.al., "On the Computation of the Discrete Cosine Transform,"
IEEE Transactions on Communications, Vol. Com-26, No. 6, Jun. 1978.

and

Wen-Hsiung Chen, et.al., "A Fast Computational Algorithm for the Discrete
Cosine Transform," IEEE Transactions on Communications, Vol. Com-25. No. 9,
Sep. 1977.


I have C code which implements the algorithm in the Chen article (with
modifications I made to order the output in bit-reversed order), if you have
interest, I can send that to you.


Paul.
