RETRO (vipl) functions
LIBRARY ROUTINE
lvgamth - Generate a binary image (value or 0) by thresholding the input image
LIBRARY CALL
/* ARGS_USED */
int lvgamth(
xvimage *image,
int rupper,
int rlower,
int gupper,
int glower,
int bupper,
int blower,
int lrflag,
int urflag,
int lgflag,
int ugflag,
int lbflag,
int ubflag,
int vflag,
int value)
INPUT
- image - input pseudo colored image in byte format
- rupper - upper threshold value for map column #1 pixel value
- rlower - lower threshold value for map column #1 pixel value
- gupper - upper threshold value for map column #2 pixel value
- glower - lower threshold value for map column #2 pixel value
- bupper - upper threshold value for map column #3 pixel value
- blower - lower threshold value for map column #3 pixel value
- lrflag - flag that says map column #1 lower thresh value is
valid
- urflag - flag that says map column #1 upper thresh value is
valid
- lgflag - flag says map column #2 lower thresh value is valid
- ugflag - flag says map column #2 upper thresh value is valid
- lbflag - flag says map map column #3 lower thresh value is
valid
- ubflag - flag says map column #3 upper thresh value is valid
- value - Value for the non-zero pixel.
OUTPUT
- image - thresheld binary output image.
RETURN VALUE
TRUE (1) on success, FALSE (0) on failure
DESCRIPTION
Generate a binary image (value or 0) by thresholding the input
color image. A color image implies the Image is of data type
BYTE, It contains 3 map columns of data type BYTE with Map
enable set to FORCE. The resulting image is of data type BYTE.
The output pixel is given the value specified by the input
variable value, if the input pixel has a value above the lower
threshold, below the upper threshold, or between the two
threshold levels.
If the lower threshold flag is set then any pixel
with value larger than the lower threshold is set
to true, otherwise false. If the upper threshold
flag is set then any pixel with value larger
than the upper threshold level is set to false,
otherwise true. If both flags are set then it is
possible to isolate a band of pixel values. If the
lower and upper threshold flags are set and the lower
and upper threshold values are equal, then the output
is set to true if it is exactly equal to the threshold
level. The region specified by the upper and lower
threshold values must be true for colormap #1 ,
colormap #2 and colormap #3 pixel values for the
above to work.
ADDITIONAL INFORMATION
none
EXAMPLES
none
SIDE EFFECTS
none
RESTRICTIONS
lvgamth will only operate on 1 band images of data type BYTE,
with the map enable FORCE, and map data type BYTE.
MODIFICATION
none
FILES
$RETRO/objects/library/vipl/src/lvgamth.c
SEE ALSO
vipl(3)
COPYRIGHT
Copyright (C) 1993 - 1997, Khoral Research, Inc. ("KRI") All rights reserved.