.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