comparison man/man1/smooth.1 @ 0:5242703e91d3 tip

Initial checkin for AIM92 aimR8.2 (last updated May 1997).
author tomwalters
date Fri, 20 May 2011 15:19:45 +0100
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1 .TH SMOOTH 1 "1 September 1993"
2
3 .SH NAME
4 smooth \- Data smoothing by convolution with Gaussian window.
5
6 .SH SYNTAX
7 smooth [options] [file]
8
9 .SH DESCRIPTION
10 Low-pass filter by convolving the input with a unit area Gaussian window
11 in the time or frequency domain.
12 The transform between domains uses the FFT.
13
14
15 .SH OPTIONS
16
17 1. length
18
19 The amount of input to smooth in time units (ms or s) or samples (no units).
20 Time units are converted to samples using the given `samplerate' option.
21 The string "max" is recognised as the remainder of input.
22
23 2. domain
24
25 Select algorithm for smoothing.
26 In the time domain ("domain=time") the discrete convolution formula is applied
27 directly as a local averaging operation on the input with weights obtained
28 by time-reversing and shifting a Gaussian window.
29 In the frequency domain ("domain=frequency") the FFT of the whole input is
30 multiplied by a Gaussian frequency response function (the FFT of the
31 Gaussian window), and the result inverse FFT'd.
32
33 3. variance, range
34
35 The variance of the Gaussian window and its
36 ordinal range in standard deviations either side of the mode.
37 The window is assumed to be zero for all time outside the specified range.
38 These parameters control the size of the window and consequently the amount
39 of smoothing. The larger the variance, the more smoothing.
40 The size of the window is given by:
41
42 .nf
43 [ 2 * range * sqrt( variance ) ] samples + 1 sample
44 .fi
45
46 The variance can be given with time units (ms or s) or samples (no units).
47 Time units are converted to samples using the given `samplerate' option.
48
49 4. type
50
51 The input and output data type. Recognised types are "short" and "float".
52
53 .SH "SEE ALSO"
54 options gauss filt1 conv
55
56 .SH COPYRIGHT
57 .LP
58 Copyright (c) Applied Psychology Unit, Medical Research Council, 1995
59 .LP
60 Permission to use, copy, modify, and distribute this software without fee
61 is hereby granted for research purposes, provided that this copyright
62 notice appears in all copies and in all supporting documentation, and that
63 the software is not redistributed for any fee (except for a nominal
64 shipping charge). Anyone wanting to incorporate all or part of this
65 software in a commercial product must obtain a license from the Medical
66 Research Council.
67 .LP
68 The MRC makes no representations about the suitability of this
69 software for any purpose. It is provided "as is" without express or
70 implied warranty.
71 .LP
72 THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
73 ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
74 THE A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES
75 OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
76 WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
77 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
78 SOFTWARE.
79