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)