vclip,vclipx − clip a region of a VisionX file

vclip
if=infile of=outfile [xl=<x>] [xh=<x>] [yl=<y>] [yh=<y>] [zl=<z>] [zh=<z>]
[c=x,y] [p=x,y] [s=x,y] [xy=x[,y]] [xs=x] [ys=y] [xp=x] [yp=y]
[zp=<z>] [zs=<x>] [-v] [-img] [f=n1[,n2]]
vclipx
if=infile of=outfile [cf=cfile]

Vclip extracts a contiguous three-dimensional region of a VisionX image file. It is a very general tool for extracting a subset of the information from files. A modified bounding box is specified by the parameters and all the data elements are clipped to fit into the modified bounding box. Vector elements are deleted if they have any part outside of the modified bounding box. Images are trimmed so that any sections that are outside of the modified bounding box are deleted.

Vclipx extracts the command line from a VisionX file that has been created with vclip and clips the specified input file. If no clip file is spcified then vclipx uses "clip.vx" which is the default file created by xvx(1).

Each of the bounding box parameters may be individually specified or left unmodified. for example

xl=20 yh=90

Specifies the the lowest x coordinate value is 20 and the highest y coordinate is 90; the other four bounding box parameters are unconstrained.

An absolute bound may be specified for any bounding box parameter. Some other methods of specifying these parameters are also made available for convenience.

For example:

p=10,20 s=40

is equivalent to specifying

xl=10 xh=50 yl=20 yh=60

The location of the lower left hand corner of the image region to extract is specified by "p=x,y". If only the x location is specified the then the y location defaults to the same value. Alternatively, the center of the image region extracted can be specified by "c=x,y". The region size in x-y space may be specified by "s=x,y" or by "xy=x,y".

The z dimension, (corresponding to the frames for image files), may be specified with zl= and zh= parameters. The f= option permits a single image frame to be selected.

The VisionX coordinate system, has x increasing from left to right, y increasing for low to high and z increasing from near to far (space) or sooner to later (time).

Images have their index origin (0,0,0) located at the lower left corner of the viewing screen; that is, the y direction increases in an upward direction. Many vision systems follow the raster convention and index images from the top left corner of the screen. Vclip will use this alternative convention if the -img option is specified.

There are two selection methods for selecting image frames: absolute index, supported by f= and z coordinate specification. (only the f= option is currently supported).

Vclip makes obsolete the old VisionX V3 commands iselect, vtrim and vgtrim.

xl=<value>

Specify the low x coordinate of the modified bounding box.

xh=<value>

Specify the high x coordinate of the modified bounding box.

yl=<value>

Specify the low y coordinate of the modified bounding box.

yh=<value>

Specify the high y coordinate of the modified bounding box.

zl=<value>

Specify the low z coordinate of the modified bounding box.

zh=<value>

Specify the high z coordinate of the modified bounding box.

s=x[,y]

xy=x[,y]

Specify the size in the x-y coordinate space of the region to be extracted.

xs=<x>

Specify the range of the region in just the x dimension.

ys=<y>

Specify the range of the region in just the y dimension.

p=x[,y]

Specify the location of the lower left corner of the region to be extracted. If only x is specified the y defaults to the same value.

xp=x

Specify the x location of the extracted region.

yp=y

Specify the y location of the extracted region.

c=x[,y]

Specify the location of the center of the region to be extracted.

-v

The -v option specifies a verbose mode of operation in which some information is printed (via standard error).

-img

The -img option selects the old conventional coordinate system for indexing images.

f=f1[,f2]

The f= parameter specifies a range of image frames to be selected.

cf=<clipfile>

The f= parameter for vclipx only, specifies a file that has been created with vclip that will supply the clipping parameters.

A. P. Reeves