gpiv_combing(1) Combines two single-exposed images into one image file


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


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.


-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.

| --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.

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


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


The program uses netpbm.


Gerber Van der Graaf