libvips/man/im_thresh.3

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.TH IM_THRESH 3 "26 April 1991"
.SH NAME
im_thresh, im_slice \- threshold an image
.SH SYNOPSIS
#include <vips/vips.h>
int im_thresh(in, out, threshold)
.br
IMAGE *in, *out;
.br
double threshold;
int im_slice(in, out, threshold1, threshold2)
.br
IMAGE *in, *out;
.br
double threshold1, threshold2;
.SH DESCRIPTION
These functions have been replaced with the relational and boolean
packages - see
.B im_lessconst()
and
.B im_and()
for much better ways of doing this.
These functions operate on any non-complex input. The output image is a
unsigned char image with the same sizes and the same number of channels as
input.
im_slice() thresholds the image held by image descriptor in and writes the
result on the image descriptor out. Output is a byte image with values less
than threshold1) set to 0, values in [threshold1, threshold2) set to 128 and
values greater than threshold2 set to 255 (x in range [a,b) means a<=x<b).
im_threshold() thresholds the image held by image descriptor in and writes the
result on the image descriptor out. Output is a byte image with values less
than threshold set to 0, and values greater or equal to threshold set to 255.
.SH RETURN VALUE
The function returns 0 on success and -1 on error.
.SH SEE\ ALSO
im_dilate(3), im_erode(3), im_lessconst(3), im_and(3).
.SH COPYRIGHT
.br
N. Dessipris,
.SH AUTHOR
N. Dessipris \- 26/04/1991