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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.
*====================================================================*/
/*
* otsutest.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "allheaders.h"
static const l_int32 NTests = 5;
static const l_int32 gaussmean1[5] = {20, 40, 60, 80, 60};
static const l_int32 gaussstdev1[5] = {10, 20, 20, 20, 30};
static const l_int32 gaussmean2[5] = {220, 200, 140, 180, 150};
static const l_int32 gaussstdev2[5] = {15, 20, 40, 20, 30};
static const l_float32 gaussfract1[5] = {0.2, 0.3, 0.1, 0.5, 0.3};
static char buf[256];
static l_int32 GenerateSplitPlot(l_int32 i);
static NUMA *MakeGaussian(l_int32 mean, l_int32 stdev, l_float32 fract);
main(int argc,
char **argv)
{
l_int32 i;
PIX *pix;
PIXA *pixa;
for (i = 0; i < NTests; i++)
GenerateSplitPlot(i);
/* Read the results back in ... */
pixa = pixaCreate(0);
for (i = 0; i < NTests; i++) {
sprintf(buf, "junkplot.%d.png", i);
pix = pixRead(buf);
pixSaveTiled(pix, pixa, 1, 1, 25, 32);
pixDestroy(&pix);
sprintf(buf, "junkplots.%d.png", i);
pix = pixRead(buf);
pixSaveTiled(pix, pixa, 1, 0, 25, 32);
pixDestroy(&pix);
}
/* ... and save into a tiled pix */
pix = pixaDisplay(pixa, 0, 0);
pixWrite("junkotsuplot.png", pix, IFF_PNG);
pixDisplay(pix, 100, 100);
pixaDestroy(&pixa);
pixDestroy(&pix);
return 0;
}
static l_int32
GenerateSplitPlot(l_int32 i)
{
char title[256];
l_int32 split;
l_float32 ave1, ave2, num1, num2, maxnum, maxscore;
GPLOT *gplot;
NUMA *na1, *na2, *nascore, *nax, *nay;
PIX *pixs, *pixd;
/* Generate */
na1 = MakeGaussian(gaussmean1[i], gaussstdev1[i], gaussfract1[i]);
na2 = MakeGaussian(gaussmean2[i], gaussstdev1[i], 1.0 - gaussfract1[i]);
numaArithOp(na1, na1, na2, L_ARITH_ADD);
/* Otsu splitting */
numaSplitDistribution(na1, 0.08, &split, &ave1, &ave2, &num1, &num2,
&nascore);
fprintf(stderr, "split = %d, ave1 = %6.1f, ave2 = %6.1f\n",
split, ave1, ave2);
fprintf(stderr, "num1 = %8.0f, num2 = %8.0f\n", num1, num2);
/* Prepare for plotting a vertical line at the split point */
nax = numaMakeConstant(split, 2);
numaGetMax(na1, &maxnum, NULL);
nay = numaMakeConstant(0, 2);
numaReplaceNumber(nay, 1, (l_int32)(0.5 * maxnum));
/* Plot the input histogram with the split location */
sprintf(buf, "junkplot.%d", i);
sprintf(title, "Plot %d", i);
gplot = gplotCreate(buf, GPLOT_PNG,
"Histogram: mixture of 2 gaussians",
"Grayscale value", "Number of pixels");
gplotAddPlot(gplot, NULL, na1, GPLOT_LINES, title);
gplotAddPlot(gplot, nax, nay, GPLOT_LINES, NULL);
gplotMakeOutput(gplot);
gplotDestroy(&gplot);
numaDestroy(&na1);
numaDestroy(&na2);
/* Plot the score function */
sprintf(buf, "junkplots.%d", i);
sprintf(title, "Plot %d", i);
gplot = gplotCreate(buf, GPLOT_PNG,
"Otsu score function for splitting",
"Grayscale value", "Score");
gplotAddPlot(gplot, NULL, nascore, GPLOT_LINES, title);
numaGetMax(nascore, &maxscore, NULL);
numaReplaceNumber(nay, 1, maxscore);
gplotAddPlot(gplot, nax, nay, GPLOT_LINES, NULL);
gplotMakeOutput(gplot);
gplotDestroy(&gplot);
numaDestroy(&nax);
numaDestroy(&nay);
numaDestroy(&nascore);
return 0;
}
static NUMA *
MakeGaussian(l_int32 mean, l_int32 stdev, l_float32 fract)
{
l_int32 i, total;
l_float32 norm, val;
NUMA *na;
na = numaMakeConstant(0.0, 256);
norm = fract / ((l_float32)stdev * sqrt(2 * 3.14159));
total = 0;
for (i = 0; i < 256; i++) {
val = norm * 1000000. * expf(-(l_float32)((i - mean) * (i - mean)) /
(l_float32)(2 * stdev * stdev));
total += (l_int32)val;
numaSetValue(na, i, val);
}
fprintf(stderr, "Total = %d\n", total);
return na;
}
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