Path: utzoo!attcan!uunet!nitrex!rbl
From: rbl@nitrex.UUCP ( Dr. Robin Lake )
Newsgroups: comp.dsp
Subject: Re: Hartley transforms
Keywords: transforms, Hartley, Fourier, FFT, FHT
Message-ID: <471@nitrex.UUCP>
Date: 6 Aug 90 11:55:18 GMT
References: <9706@life.ai.mit.edu>
Reply-To: rbl@nitrex.UUCP (Robin Lake)
Organization: BP Research International - Research Center Warrensville,  Cleveland, OH
Lines: 36

In article <9706@life.ai.mit.edu> tmb@ai.mit.edu writes:
| >Does anyone know or have pointers to the literature or code about how
| >to do multidimensional Hartley transforms (i.e., is it obvious that a
| >2D HT is the same as 2 1D HT's, or do I need some correction), and what
| >the correlation and convolution theorems look like for multidimensional
| >Hartley transforms?
| >
...
| >
| >Also, does anyone have code for the FHT (C/Fortran)? Currently, I am
| >using a REALFFT routine and re-arrange the output, which is probably
| >not very inefficient, but not quite as fast as it could be.  Have the
| >patent issues involving the FHT been resolved?
| >
| >					Thanks, Thomas.
| >					tmb@ai.mit.edu
| >
| >PS: the Hartley transform is a real transform that is
| >closely related to the Fourier transform and has some
| >practical advantages over it if all you want to do is
| >operate on real data.


Perhaps not right on target, but I find the following at hand:

R. N. Bracewell "Numerical Transforms"  Science, 11 May 1990, pg 697ff.

P. Duhamel and M.  Vetterli "Improved Fourier and Hartley Transform Algorithms ... "
IEEE Trans ASSP.  #6, June 1987, pg.818 ff.

Surprisingly, nothing in the books on Fast Algorithms or MultiDimensional
Signal Processing.

Rob Lake
BP Research
rbl@BP.COM