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Diffstat (limited to 'leptonica/prog/otsutest2.c')
| -rw-r--r-- | leptonica/prog/otsutest2.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/leptonica/prog/otsutest2.c b/leptonica/prog/otsutest2.c new file mode 100644 index 00000000..cbe94f45 --- /dev/null +++ b/leptonica/prog/otsutest2.c @@ -0,0 +1,129 @@ +/*====================================================================* + - Copyright (C) 2001 Leptonica. All rights reserved. + - + - Redistribution and use in source and binary forms, with or without + - modification, are permitted provided that the following conditions + - are met: + - 1. Redistributions of source code must retain the above copyright + - notice, this list of conditions and the following disclaimer. + - 2. Redistributions in binary form must reproduce the above + - copyright notice, this list of conditions and the following + - disclaimer in the documentation and/or other materials + - provided with the distribution. + - + - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + - ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + - A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY + - CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + - EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + - PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + - PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + - OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + - NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + - SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + *====================================================================*/ + +/* + * otsutest2.c + * + * This demonstrates the usefulness of the modified version of Otsu + * for thresholding an image that doesn't have a well-defined + * background color. + * + * Standard Otsu binarization is done with scorefract = 0.0, which + * returns the threshold at the maximum value of the score. However. + * this value is up on the shoulder of the background, and its + * use causes some of the dark background to be binarized as foreground. + * + * Using the modified Otsu with scorefract = 0.1 returns a threshold + * at the lowest value of this histogram such that the score + * is at least 0.9 times the maximum value of the score. This allows + * the threshold to be taken in the histogram minimum between + * the fg and bg peaks, producing a much cleaner binarization. + */ + + +#ifdef HAVE_CONFIG_H +#include <config_auto.h> +#endif /* HAVE_CONFIG_H */ + +#include "allheaders.h" + + +int main(int argc, + char **argv) +{ +char textstr[256]; +l_int32 i, thresh, fgval, bgval; +l_float32 scorefract; +L_BMF *bmf; +PIX *pixs, *pixb, *pixg, *pixp, *pix1, *pix2, *pix3; +PIXA *pixa1, *pixad; + + setLeptDebugOK(1); + lept_mkdir("lept/otsu"); + + pixs = pixRead("1555.007.jpg"); + pixg = pixConvertTo8(pixs, 0); + bmf = bmfCreate(NULL, 8); + pixad = pixaCreate(0); + for (i = 0; i < 3; i++) { + pixa1 = pixaCreate(2); + scorefract = 0.1 * i; + + /* Get a 1 bpp version; use a single tile */ + pixOtsuAdaptiveThreshold(pixg, 2000, 2000, 0, 0, scorefract, + NULL, &pixb); + pixaAddPix(pixa1, pixg, L_COPY); + pixaAddPix(pixa1, pixb, L_INSERT); + + /* Show the histogram of gray values and the split location */ + pixSplitDistributionFgBg(pixg, scorefract, 1, + &thresh, &fgval, &bgval, &pixp); + lept_stderr("thresh = %d, fgval = %d, bgval = %d\n", + thresh, fgval, bgval); + pixaAddPix(pixa1, pixp, L_INSERT); + + /* Join these together and add some text */ + pix1 = pixaDisplayTiledInColumns(pixa1, 3, 1.0, 20, 2); + snprintf(textstr, sizeof(textstr), + "Scorefract = %3.1f ........... Thresh = %d", scorefract, thresh); + pix2 = pixAddSingleTextblock(pix1, bmf, textstr, 0x00ff0000, + L_ADD_BELOW, NULL); + + /* Save and display the result */ + pixaAddPix(pixad, pix2, L_INSERT); + snprintf(textstr, sizeof(textstr), "/tmp/lept/otsu/%03d.png", i); + pixWrite(textstr, pix2, IFF_PNG); + pixDisplay(pix2, 100, 100); + pixDestroy(&pix1); + pixaDestroy(&pixa1); + } + + /* Use a smaller tile for Otsu */ + for (i = 0; i < 2; i++) { + scorefract = 0.1 * i; + pixOtsuAdaptiveThreshold(pixg, 300, 300, 0, 0, scorefract, + NULL, &pixb); + pix1 = pixAddBlackOrWhiteBorder(pixb, 2, 2, 2, 2, L_GET_BLACK_VAL); + pix2 = pixScale(pix1, 0.5, 0.5); + snprintf(textstr, sizeof(textstr), + "Scorefract = %3.1f", scorefract); + pix3 = pixAddSingleTextblock(pix2, bmf, textstr, 1, + L_ADD_BELOW, NULL); + pixaAddPix(pixad, pix3, L_INSERT); + pixDestroy(&pixb); + pixDestroy(&pix1); + pixDestroy(&pix2); + } + + lept_stderr("Writing to: /tmp/lept/otsu/result1.pdf\n"); + pixaConvertToPdf(pixad, 75, 1.0, 0, 0, "Otsu thresholding", + "/tmp/lept/otsu/result1.pdf"); + bmfDestroy(&bmf); + pixDestroy(&pixs); + pixDestroy(&pixg); + pixaDestroy(&pixad); + return 0; +} |