im_heq, im_lhisteq, im_lhisteq_raw, im_hsp - process an image using grey level transformations
#include <vips/vips.h> int im_heq( in, out, bandno ) IMAGE *in, *out; int bandno; int im_lhisteq( in, out, xw, yw ) IMAGE *in, *out; int xw, yw; int im_hsp( in, ref, out ) IMAGE *in, *ref, *out;
im_heq(3) histogram equalises the unsigned char image held by the IMAGE descriptor in. The result is written to the IMAGE descriptor out. If bandno is -1 then all input bands are equalised independently. In all other cases the input image is equalised using the histogram of bandno only. The latter processing produces better results..
All functions returns 0 on success and -1 on error.
im_histgr(3), im_histplot(3), im_histspec(3), im_lineprof(3), im_stdif(3).
1991--1996 The National Gallery and Birkbeck College 10 May 1991