/*====================================================================* - 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. *====================================================================*/ /* * skewtest.c * * Tests various skew finding methods, optionally deskewing * the input (binary) image. The best version does a linear * sweep followed by a binary (angle-splitting) search. * The basic method is to find the vertical shear angle such * that the differential variance of ON pixels between each * line and it's neighbor, when summed over all lines, is * maximized. */ #ifdef HAVE_CONFIG_H #include #endif /* HAVE_CONFIG_H */ #include "allheaders.h" /* binarization threshold */ #define BIN_THRESHOLD 130 /* deskew */ #define DESKEW_REDUCTION 2 /* 1, 2 or 4 */ /* sweep only */ #define SWEEP_RANGE 10. /* degrees */ #define SWEEP_DELTA 0.2 /* degrees */ #define SWEEP_REDUCTION 2 /* 1, 2, 4 or 8 */ /* sweep and search */ #define SWEEP_RANGE2 10. /* degrees */ #define SWEEP_DELTA2 1. /* degrees */ #define SWEEP_REDUCTION2 2 /* 1, 2, 4 or 8 */ #define SEARCH_REDUCTION 2 /* 1, 2, 4 or 8 */ #define SEARCH_MIN_DELTA 0.01 /* degrees */ int main(int argc, char **argv) { char *filein; l_int32 ret; l_float32 deg2rad; l_float32 angle, conf, score, endscore; PIX *pix, *pixs, *pixd; static char mainName[] = "skewtest"; if (argc != 2) return ERROR_INT(" Syntax: skewtest filein", mainName, 1); filein = argv[1]; setLeptDebugOK(1); lept_rmdir("lept/deskew"); lept_mkdir("lept/deskew"); pixd = NULL; deg2rad = 3.1415926535 / 180.; if ((pixs = pixRead(filein)) == NULL) return ERROR_INT("pixs not made", mainName, 1); /* Find the skew angle various ways */ pix = pixConvertTo1(pixs, BIN_THRESHOLD); pixWrite("/tmp/lept/deskew/binarized.tif", pix, IFF_TIFF_G4); pixFindSkew(pix, &angle, &conf); lept_stderr("pixFindSkew():\n" " conf = %5.3f, angle = %7.3f degrees\n", conf, angle); pixFindSkewSweepAndSearchScorePivot(pix, &angle, &conf, &score, SWEEP_REDUCTION2, SEARCH_REDUCTION, 0.0, SWEEP_RANGE2, SWEEP_DELTA2, SEARCH_MIN_DELTA, L_SHEAR_ABOUT_CORNER); lept_stderr("pixFind...Pivot(about corner):\n" " conf = %5.3f, angle = %7.3f degrees, score = %.0f\n", conf, angle, score); pixFindSkewSweepAndSearchScorePivot(pix, &angle, &conf, &score, SWEEP_REDUCTION2, SEARCH_REDUCTION, 0.0, SWEEP_RANGE2, SWEEP_DELTA2, SEARCH_MIN_DELTA, L_SHEAR_ABOUT_CENTER); lept_stderr("pixFind...Pivot(about center):\n" " conf = %5.3f, angle = %7.3f degrees, score = %.0f\n", conf, angle, score); /* Use top-level */ pixd = pixDeskew(pixs, 0); pixWriteImpliedFormat("/tmp/lept/deskew/result1", pixd, 0, 0); pixDestroy(&pix); pixDestroy(&pixd); #if 1 /* Do skew finding and rotation separately. This fails if * the skew angle is outside the range. */ pix = pixConvertTo1(pixs, BIN_THRESHOLD); if (pixGetDepth(pixs) == 1) { pixd = pixDeskew(pix, DESKEW_REDUCTION); pixWrite("/tmp/lept/deskew/result2", pixd, IFF_PNG); } else { ret = pixFindSkewSweepAndSearch(pix, &angle, &conf, SWEEP_REDUCTION2, SEARCH_REDUCTION, SWEEP_RANGE2, SWEEP_DELTA2, SEARCH_MIN_DELTA); if (ret) L_WARNING("skew angle not valid\n", mainName); else { lept_stderr("conf = %5.3f, angle = %7.3f degrees\n", conf, angle); if (conf > 2.5) pixd = pixRotate(pixs, angle * deg2rad, L_ROTATE_AREA_MAP, L_BRING_IN_WHITE, 0, 0); else pixd = pixClone(pixs); pixWrite("/tmp/lept/deskew/result2", pixd, IFF_PNG); pixDestroy(&pixd); } } pixDestroy(&pix); #endif #if 1 pixFindSkewSweepAndSearchScore(pixs, &angle, &conf, &endscore, 4, 2, 0.0, 5.0, 1.0, 0.01); lept_stderr("angle = %8.4f, conf = %8.4f, endscore = %.0f\n", angle, conf, endscore); startTimer(); pixd = pixDeskew(pixs, DESKEW_REDUCTION); lept_stderr("Time to deskew = %7.4f sec\n", stopTimer()); pixWrite("/tmp/lept/deskew/result3", pixd, IFF_PNG); pixDestroy(&pixd); #endif #if 1 ret = pixFindSkew(pixs, &angle, &conf); lept_stderr("angle = %8.4f, conf = %8.4f\n", angle, conf); if (ret) { L_WARNING("skew angle not valid\n", mainName); return 1; } #endif #if 1 ret = pixFindSkewSweep(pixs, &angle, SWEEP_REDUCTION, SWEEP_RANGE, SWEEP_DELTA); lept_stderr("angle = %8.4f, conf = %8.4f\n", angle, conf); if (ret) { L_WARNING("skew angle not valid\n", mainName); return 1; } #endif #if 1 ret = pixFindSkewSweepAndSearch(pixs, &angle, &conf, SWEEP_REDUCTION2, SEARCH_REDUCTION, SWEEP_RANGE2, SWEEP_DELTA2, SEARCH_MIN_DELTA); lept_stderr("angle = %8.4f, conf = %8.4f\n", angle, conf); if (ret) { L_WARNING("skew angle not valid\n", mainName); return 1; } #endif pixDestroy(&pixs); return 0; }