GPIV_COMBING(1) 					      General Commands Manual						   GPIV_COMBING(1)

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 sepa-
	      ration 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  for-
	      mat 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 com-
	      bined 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_base-
       name 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)