NAME

       gpiv_combing  -  Combines  two  single-exposed  images  into  one  image  file  for cross-
       correlation.

SYNOPSIS

       gpiv_combing [-a | --suf_a S] [-b | --suf_b S] [-d | --dt S] [-h | --help] [-p |  --print]
       [-s  |  --skip S] [-t | --type] [-u | --suf_num N] [-v | --version] [-V | --verbose] [-w |
       --warning] file_basename

DESCRIPTION

       gpiv_combing combines two images from a common image format that use lossless  compressing
       schemes  into a Portable Network Graphics image with extension .png. The resulting ´double
       frame´ image is used for cross-correlation with gpiv_rr (or gpiv). Additional  information
       is  added  to  the  image  header,  like  the  parameter  for  enabling cross correlation,
       separation time between the recordings of the two images and the name of this program.

       This program uses the IMG configuration parameters. As the input images  are  single-frame
       and  will probably not contain the required X_corr parameter in its header, the IMG.X_corr
       setting will have to be set to 0 for the correct loading.

       The default settings may be overruled by the command line options, as explained below.

Options

       -h | --help
              On-line help.

       -a | --suf_a S
              The filename of the first image is generated from the file_basename, the  suffix  S
              (default: _a) and from the image extension type.

       -b | --suf_b S
              The  filename of the second image is generated from the file_basename, the suffix S
              (default: _b) and from the image extension type.

       -d | --dt S
              The time between subsequent images in milliseconds. The value will  be  written  to
              the  image  header.  If -s | --skip is used, the separation time will be adapted to
              the correct value.

       -p | --print
              Prints parameters to stdout.

       -s | --skip S
              Skip S numbers; the first image with number N (defined by -u | --suf_num N) will be
              combined with the second image N+S+1 (default: S = 0)

       -t | --type
              Type  or format of the input image (default png). Supported formats are: raw binary
              (r), hdf5 (gpi), gif, tif, bmp and pgm. The format of the output image will  always
              be png.

       -u | --suf_num N
              If images are numbered instead of having suffixes _a and _b. N represents the first
              of the two numbered frames which will be combined with frame N +  1.  The  combined
              image  will  be  named to file_basenameN.png.  So, only odd or even numbered images
              will result to be loaded in gpiv_rr (or gpiv) for cross-correlation.

       -v | --version
              Print version information on standard output, then exit successfully.

       -V | --verbose
              Program behaves verbose during operation, like printing filenames, separation time.

       -w | --warning
              Checks and warns if one of the two input images already contain an image pair, i.e.
              the header parameter X-corr is set TRUE. The program will exit if this is the case.
              Besides this warning, the program will always check if  the  images  are  of  equal
              sizes.  If  an input image does not contain the X-corr parameter in its header, the
              parameter will be read from the parameter resources. Not using this  option  allows
              one to keep the settings in the parameter resources in any state.

       file_basename
              The  filename  without  the  image  extension  (like  .png, .tif etc) and suffix or
              number.

       Examples

       Suppose two single-exposed images will have to  be  combined  for  cross-correlation  with
       names  image_a.gif  and  image_b.gif:  so the file_basename will be "image", _a and _b are
       default suffixes and the image type has to be defined. The program is used following:
              gpiv_combing -t gif image

       As  PNG  is  default  image  format,  -t  key  is  not  needed.  Two  images  with   names
       turtle_slow.png and turtle_fast.png are combined with:
              gpiv_combing -a _slow -b _fast turtle

       For  two  numbered  images  img03.png  and img04.png only the starting number will have to
       defined:
              gpiv_combing -u 3 img0

       Two numbered images img03.png and img09.png will have to be combined by skipping 5  images
       in-between.  If  -d  |  --dt  S  is used, the correct separation time between the combined
       frames is calculated from S:
              gpiv_combing -u 3 -s 5 img0

       SEE ALSO
              gpivtools

NOTES

       The program uses netpbm.

AUTHOR

       Gerber Van der Graaf

                                         31 October 2006                          GPIV_COMBING(1)