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/*====================================================================*
- Copyright (C) 2001 Leptonica. All rights reserved.
- This software is distributed in the hope that it will be
- useful, but with NO WARRANTY OF ANY KIND.
- No author or distributor accepts responsibility to anyone for the
- consequences of using this software, or for whether it serves any
- particular purpose or works at all, unless he or she says so in
- writing. Everyone is granted permission to copy, modify and
- redistribute this source code, for commercial or non-commercial
- purposes, with the following restrictions: (1) the origin of this
- source code must not be misrepresented; (2) modified versions must
- be plainly marked as such; and (3) this notice may not be removed
- or altered from any source or modified source distribution.
*====================================================================*/
/*
* comparetest.c
*
* comparetest filein1 filein2 type fileout
*
* where
* type = {0, 1} for {abs-diff and subtraction} comparisons
*
* Compares two images, using either the absolute value of the
* pixel differences or the difference clipped to 0. For RGB,
* the differences are computed separately on each component.
* If one has a colormap and the other doesn't, the colormap
* is removed before making the comparison.
*
* Warning: you usually want to use abs-diff to compare
* two grayscale or color images. If you use subtraction,
* the result you get will depend on the order of the input images.
* For example, if pix2 = pixDilateGray(pix1), then every
* pixel in pix1 will be equal to or greater than pix2. So if
* you subtract pix2 from pix1, you will get 0 for all pixels,
* which looks like they're the same!
*
* Here's an interesting observation. Take an image that has
* been jpeg compressed at a quality = 75. If you re-compress
* the image, what quality factor should be used to minimize
* the change? Answer: 75 (!)
*/
#include <stdio.h>
#include <stdlib.h>
#include "allheaders.h"
main(int argc,
char **argv)
{
l_int32 type, comptype, d1, d2, same, first, last;
l_float32 fract, diff, rmsdiff;
char *filein1, *filein2, *fileout;
GPLOT *gplot;
NUMA *na1, *na2;
PIX *pixs1, *pixs2, *pixd;
static char mainName[] = "comparetest";
if (argc != 5)
exit(ERROR_INT(" Syntax: comparetest filein1 filein2 type fileout",
mainName, 1));
filein1 = argv[1];
filein2 = argv[2];
type = atoi(argv[3]);
pixd = NULL;
fileout = argv[4];
if ((pixs1 = pixRead(filein1)) == NULL)
exit(ERROR_INT("pixs1 not made", mainName, 1));
if ((pixs2 = pixRead(filein2)) == NULL)
exit(ERROR_INT("pixs2 not made", mainName, 1));
d1 = pixGetDepth(pixs1);
d2 = pixGetDepth(pixs2);
if (d1 == 1 && d2 == 1) {
if (type == 0)
comptype = L_COMPARE_XOR;
else
comptype = L_COMPARE_SUBTRACT;
pixCompareBinary(pixs1, pixs2, comptype, &fract, &pixd);
fprintf(stderr, "Fraction of different pixels: %10.6f\n", fract);
pixWrite(fileout, pixd, IFF_PNG);
}
else {
if (type == 0)
comptype = L_COMPARE_ABS_DIFF;
else
comptype = L_COMPARE_SUBTRACT;
pixCompareGrayOrRGB(pixs1, pixs2, comptype, GPLOT_X11, &same, &diff,
&rmsdiff, &pixd);
if (type == 0) {
if (same)
fprintf(stderr, "Images are identical\n");
else {
fprintf(stderr, "Images differ: <diff> = %10.6f\n", diff);
fprintf(stderr, " <rmsdiff> = %10.6f\n", rmsdiff);
}
}
else { /* subtraction */
if (same)
fprintf(stderr, "pixs2 strictly greater than pixs1\n");
else {
fprintf(stderr, "Images differ: <diff> = %10.6f\n", diff);
fprintf(stderr, " <rmsdiff> = %10.6f\n", rmsdiff);
}
}
pixWrite(fileout, pixd, IFF_JFIF_JPEG);
}
na1 = pixCompareRankDifference(pixs1, pixs2);
fprintf(stderr, "na1[150] = %20.10f\n", na1->array[150]);
fprintf(stderr, "na1[200] = %20.10f\n", na1->array[200]);
fprintf(stderr, "na1[250] = %20.10f\n", na1->array[250]);
numaGetNonzeroRange(na1, 0.00005, &first, &last);
fprintf(stderr, "Nonzero diff range: first = %d, last = %d\n", first, last);
na2 = numaClipToInterval(na1, first, last);
gplot = gplotCreate("/usr/tmp/junkrank", GPLOT_X11,
"Pixel Rank Difference", "pixel val",
"rank");
gplotAddPlot(gplot, NULL, na2, GPLOT_LINES, "rank");
gplotMakeOutput(gplot);
gplotDestroy(&gplot);
numaDestroy(&na1);
numaDestroy(&na2);
pixDestroy(&pixs1);
pixDestroy(&pixs2);
pixDestroy(&pixd);
exit(0);
}
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