Mercurial > hg > aim92
diff man/man1/acgram.1 @ 0:5242703e91d3 tip
Initial checkin for AIM92 aimR8.2 (last updated May 1997).
author | tomwalters |
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date | Fri, 20 May 2011 15:19:45 +0100 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/man/man1/acgram.1 Fri May 20 15:19:45 2011 +0100 @@ -0,0 +1,104 @@ +.TH ACGRAM 1 "1 September 1993" + +.SH NAME +acgram \- Autocorrelogram auditory image. + +.SH SYNTAX +acgram [arguments] [file] + + +.SH DESCRIPTION +Short-time autocorrelation function applied to each row of input frames. +Output frames consist of row-wise autocorrelation coefficients. +The autocorrelation function (acf) is computed using the fft. Strictly +speaking this generates an autocovariance function, but an optional +normalization (dividing each coefficient by the zeroth coefficient) produces +the autocorrelation function. + +The program expects to read an AIM header, and interprets input as one large +frame in column-wise format (eg output from genbmm, gennap, etc.), to be +divided into input frames, each to be processed as an autocorrelogram. +A new header is constructed, and each autocorrelogram frame is output in +row-wise format (eg as if output from gensai). + +The input is divided into frames according to the given options. +The options 'start' and 'length' specify the input file. +The special option value length=max specifies all the input file from +the given start to its end. +The options 'width' and 'frstep' specify the input frames. +The width option is the framewidth of each input frame and the frstep +option is the frameshift between input frames in the input file. +The special option value width=max specifies the input framewidth as equal +to the given input file length, (and if this is also 'max', then the +input framewidth is the remainder of the input file). + +Most options in the input header are copied to the output header. +This enables options which are needed for the eventual display +to pass straight through. Some options are set so that they can override +the input header. For example, the display option is set on to enable +display even when input has display=off. The animate option can be set on +even when the input has animate=off. +Some parts of the header are changed for the output format: +(frames, frameshift, framewidth, frameheight, framebytes). + +Each row of each input frame is padded with zeroes to the next +power of 2 larger than either the original input framewidth or twice the +max acf lag (whichever is the larger). +If necessary, extra padding can be enforced using the (silent) padding option +to add extra zeroes, padding to a larger power of 2. +The amount of extra padding is 'exponential', expanding the basic size to: +.nf + ( framewidth + padding ) * 2**n + +where the padding option is n. +.fi + +(n=0 by default, so that no extra padding is added. When n=1 then padding is +added to double the size, and when n=2 the size is quadrupled, etc.). + +.SH EXAMPLES + +1. Autocorrelogram of a NAP, animated and normalized, with max lag 16ms: + +gennap len=128ms output=stdout display=off file | acgram lag=16ms norm=on \ +anim=on > file.sai + +gensai useprev=on headr=5 top=1000 file -(for landscape plot) + +genspl useprev=on headr=5 top=1000 pensize=2 file -(for spiral plot) + +2. Autocorrelogram of an SAI: + (gensai removes file.sai, so you must use some other name, eg foo.sai). + +gensai len=64 pwidth=64 nwidth=0 output=stdout display=off file | \ +saitonap frame=3 | acgram lag=32ms frame=1 > foo.sai + +gensai useprev=on top=1000 headr=5 mag=2 foo + + +.SH COPYRIGHT +.LP +Copyright (c) Applied Psychology Unit, Medical Research Council, 1995 +.LP +Permission to use, copy, modify, and distribute this software without fee +is hereby granted for research purposes, provided that this copyright +notice appears in all copies and in all supporting documentation, and that +the software is not redistributed for any fee (except for a nominal +shipping charge). Anyone wanting to incorporate all or part of this +software in a commercial product must obtain a license from the Medical +Research Council. +.LP +The MRC makes no representations about the suitability of this +software for any purpose. It is provided "as is" without express or +implied warranty. +.LP +THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, +INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO +EVENT SHALL THE A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR +CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF +USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR +OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR +PERFORMANCE OF THIS SOFTWARE. + + +