doc/C/errvec.html

   1 <HTML><HEAD><TITLE>Manpage of </TITLE>
   2 </HEAD><BODY BGCOLOR="#FFFFFF">
   3 Name: <B>ERRVEC</B><BR>
   4 Section: User Commands  (1)
   5 <HR>
   6
   7 <A NAME="NAME" id="NAME">&nbsp;</A><A NAME="lbAB" id="lbAB">&nbsp;</A>
   8 <H2>NAME</H2>
   9
  10 errvec - Searches erroneous vectors in a PIV data file and substitutes
  11 with new values.
  12 <A NAME="SYNOPSIS" id="SYNOPSIS">&nbsp;</A><A NAME="lbAC" id="lbAC">&nbsp;</A>
  13 <H2>SYNOPSIS</H2>
  14
  15 <P>
  16 <B>errvec</B> [<B>-f </B><I>filename</I>]
  17 [<B>-h</B>][<B>-p</B>] [<B>-b </B> || --b] [<B>-bn </B><I>N</I>] [<B>-g</B>][<B>-h</B>]
  18 [<B>-r </B><I>N</I>] [<B>-s </B><I>N</I>] [<B>-t </B><I>F</I>] [<B>-ta</B>] [<B>-v</B>]  &lt; <I>stdin</I> &gt; <I>stdout</I>
  19 <P>
  20
  21 <P>
  22 <A NAME="DESCRIPTION" id="DESCRIPTION">&nbsp;</A><A NAME="lbAD" id="lbAD">&nbsp;</A>
  23 <H2>DESCRIPTION</H2>
  24
  25 <P>
  26 <B>errvec</B> searches erroneous outliers in a PIV data stream and
  27 substitutes with new values, if possible, i.e. if (the majority) of its
  28 surroundings are non-erroneous.  Evaluation of erroneous vectors is
  29 done by looking up the Signal to Noise Ratio (SNR) value in the PIV
  30 data file or by calculating the median residu of the vector with its
  31 surroundings. A new displacement is obtained by the mean value of the
  32 surrounding values or by the x-and y displacements belonging to the
  33 median value or by the location of the next higher peak in the
  34 covariance function. The latter needs the use of <I>rr</I>.
  35 <P>
  36 The parameters and options to be used for <I>errvec</I> are
  37 subsequently searched <I>errvec.par</I> at local directory at
  38 <I>~/.gpivrc</I> or at<I>/etc/gpivrc</I>. Each parameter is
  39 described by the program key (Err_V)
  40 and the parameter name, separated by a dot (.), followed by its
  41 value. Some of the parameters are optional. The parameters may be
  42 defined in arbitrary order. Blank lines and comment (starting with a
  43 pound sign (#) at the first column) may be included in the parameter
  44 files.  The parameters may be overruled by the command line options,
  45 as explained below.
  46 <P>
  47 <A NAME="Options_" id="Options_">&nbsp;</A><A NAME="lbAE" id="lbAE">&nbsp;</A>
  48 <H2>Options </H2>
  49
  50 <DL COMPACT>
  51 <DT><B>-b </B><I>N</I><DD>
  52 Calculate statistics of the median residues and print a histogram of
  53 <I>N</I> bins.
  54 <DT><B>-f </B><I>filename</I> <DD>
  55 Overrides stdin and stdout with <I>filename</I>. The filename has to be
  56 given without its <B>.piv</B> extension. Output will be written to
  57 <I>filename</I><B>.erv.piv</B>. The parameters will be written or appended
  58 to <I>filename</I><B>.par</B>. Other files, like image header file
  59 <I>filename</I><B>.h</B> and raw data file(s) <I>filename.</I><B>1.r</B> and
  60 <I>filename</I><B>.1.r</B> (in case of cross-correlation) or
  61 <I>filename</I><B>.r</B> (in case of auto-correlation) are needed if a
  62 particle displacement will have to be estimated by <B>rr</B>.
  63 <DT><B>-g</B><DD>
  64 Graphical visualization of residu statistcs with gnuplot.
  65 <DT><B>-h</B><DD>
  66 On-line help.
  67 <DT><B>-p</B><DD>
  68 Print parameters, command line options and eventually used input and
  69 output filenames to stdout. The output may be used as parameters of
  70 <B>errvec</B> for future use by re-directing stdout to
  71 <B>errvec.par</B>.
  72 <DT><B>-r </B><I>N</I> <DD>
  73 Erroneous vector determined by SNR of the covariance function
  74 (<I>N</I> = 0) or median residu (<I>N</I> = 1).
  75 <DT><B>-s </B><I>N</I><DD>
  76 Substitution of the erroneous vectors by the mean of
  77 the surrounding values
  78 (<I>N</I> = 0), median (<I>N</I> = 1) or next highest covariance peak
  79 (<I>N</I> = 2).
  80 <DT><B>-t </B><I>F</I> <DD>
  81 Threshhold value <I>F</I> of SNR or median residu to
  82 determine validity of particle displacement.
  83 <DT><B>-ta</B> <DD>
  84 Automatic threshold; calculates threshhold value from residu histogram.
  85 <DT><B>-v</B><DD>
  86 Print version information on standard output, then exit successfully.
  87 </DL>
  88 <A NAME="SEE_ALSO" id="SEE_ALSO">&nbsp;</A><A NAME="lbAF" id="lbAF">&nbsp;</A>
  89 <H2>SEE ALSO</H2>
  90
  91 batch-gp, dav2piv, manipiv, hilo, rr, scale, s-avg, t-avg, peaklck,
  92 piv2vec,vorstra
  93 <P>
  94 <A NAME="NOTES" id="NOTES">&nbsp;</A><A NAME="lbAG" id="lbAG">&nbsp;</A>
  95 <H2>NOTES</H2>
  96
  97 stdin and stdout has still to be implemented.
  98 [<B>-f</B> <I>filename </I>] will be added.
  99 <P>
 100 <A NAME="AUTHOR" id="AUTHOR">&nbsp;</A><A NAME="lbAH" id="lbAH">&nbsp;</A>
 101 <H2>AUTHOR</H2>
 102
 103 Gerber Van der Graaf
 104 <P>
 105 <A NAME="BUGS" id="BUGS">&nbsp;</A><A NAME="lbAI" id="lbAI">&nbsp;</A>
 106 <H2>BUGS</H2>
 107
 108 The program has been tested for artifical generated DPIV images. So far, no
 109 serious bugs have been found.
 110 <P>
 111
 112 <HR>
 113 <A NAME="index">&nbsp;</A><H2>Table of Contents</H2>
 114 <OL>
 115 <LI><A HREF="#lbAB">Name</A>
 116 <LI><A HREF="#lbAC">Synopsis</A>
 117 <LI><A HREF="#lbAD">Description</A>
 118 <LI><A HREF="#lbAE">Options </A>
 119 <LI><A HREF="#lbAF">See also</A>
 120 <LI><A HREF="#lbAG">Notes</A>
 121 <LI><A HREF="#lbAH">Author</A>
 122 <LI><A HREF="#lbAI">Bugs</A>
 123 </OL>
 124 </BODY>
 125 </HTML>