/*! * pixaAddBorderGeneral() * * Input: pixad (can be null or equal to pixas) * pixas (containing pix of all depths; colormap ok) * left, right, top, bot (number of pixels added) * val (value of added border pixels) * Return: pixad (with border added to each pix), including on error * * Notes: * (1) For binary images: * white: val = 0 * black: val = 1 * For grayscale images: * white: val = 2 ** d - 1 * black: val = 0 * For rgb color images: * white: val = 0xffffff00 * black: val = 0 * For colormapped images, use 'index' found this way: * white: pixcmapGetRankIntensity(cmap, 1.0, &index); * black: pixcmapGetRankIntensity(cmap, 0.0, &index); * (2) For in-place replacement of each pix with a bordered version, * use @pixad = @pixas. To make a new pixa, use @pixad = NULL. * (3) In both cases, the boxa has sides adjusted as if it were * expanded by the border. */ PIXA * pixaAddBorderGeneral(PIXA *pixad, PIXA *pixas, l_int32 left, l_int32 right, l_int32 top, l_int32 bot, l_uint32 val) { l_int32 i, n, nbox; BOX *box; BOXA *boxad; PIX *pixs, *pixd; PROCNAME("pixaAddBorderGeneral"); if (!pixas) return (PIXA *)ERROR_PTR("pixas not defined", procName, pixad); if (left < 0 || right < 0 || top < 0 || bot < 0) return (PIXA *)ERROR_PTR("negative border added!", procName, pixad); if (pixad && (pixad != pixas)) return (PIXA *)ERROR_PTR("pixad defined but != pixas", procName, pixad); n = pixaGetCount(pixas); if (!pixad) pixad = pixaCreate(n); for (i = 0; i < n; i++) { pixs = pixaGetPix(pixas, i, L_CLONE); pixd = pixAddBorderGeneral(pixs, left, right, top, bot, val); if (pixad == pixas) /* replace */ pixaReplacePix(pixad, i, pixd, NULL); else pixaAddPix(pixad, pixd, L_INSERT); pixDestroy(&pixs); } nbox = pixaGetBoxaCount(pixas); boxad = pixaGetBoxa(pixad, L_CLONE); for (i = 0; i < nbox; i++) { if ((box = pixaGetBox(pixas, i, L_COPY)) == NULL) { L_WARNING_INT("box %d not found", procName, i); break; } boxAdjustSides(box, box, -left, right, -top, bot); if (pixad == pixas) /* replace */ boxaReplaceBox(boxad, i, box); else boxaAddBox(boxad, box, L_INSERT); } boxaDestroy(&boxad); return pixad; }
/*! * pixFindPageForeground() * * Input: pixs (full resolution (any type or depth) * threshold (for binarization; typically about 128) * mindist (min distance of text from border to allow * cleaning near border; at 2x reduction, this * should be larger than 50; typically about 70) * erasedist (when conditions are satisfied, erase anything * within this distance of the edge; * typically 30 at 2x reduction) * pagenum (use for debugging when called repeatedly; labels * debug images that are assembled into pdfdir) * showmorph (set to a negative integer to show steps in * generating masks; this is typically used * for debugging region extraction) * display (set to 1 to display mask and selected region * for debugging a single page) * pdfdir (subdirectory of /tmp where images showing the * result are placed when called repeatedly; use * null if no output requested) * Return: box (region including foreground, with some pixel noise * removed), or null if not found * * Notes: * (1) This doesn't simply crop to the fg. It attempts to remove * pixel noise and junk at the edge of the image before cropping. * The input @threshold is used if pixs is not 1 bpp. * (2) There are several debugging options, determined by the * last 4 arguments. * (3) If you want pdf output of results when called repeatedly, * the pagenum arg labels the images written, which go into * /tmp/<pdfdir>/<pagenum>.png. In that case, * you would clean out the /tmp directory before calling this * function on each page: * lept_rmdir(pdfdir); * lept_mkdir(pdfdir); */ BOX * pixFindPageForeground(PIX *pixs, l_int32 threshold, l_int32 mindist, l_int32 erasedist, l_int32 pagenum, l_int32 showmorph, l_int32 display, const char *pdfdir) { char buf[64]; l_int32 flag, nbox, intersects; l_int32 w, h, bx, by, bw, bh, left, right, top, bottom; PIX *pixb, *pixb2, *pixseed, *pixsf, *pixm, *pix1, *pixg2; BOX *box, *boxfg, *boxin, *boxd; BOXA *ba1, *ba2; PROCNAME("pixFindPageForeground"); if (!pixs) return (BOX *)ERROR_PTR("pixs not defined", procName, NULL); /* Binarize, downscale by 0.5, remove the noise to generate a seed, * and do a seedfill back from the seed into those 8-connected * components of the binarized image for which there was at least * one seed pixel. Also clear out any components that are within * 10 pixels of the edge at 2x reduction. */ flag = (showmorph) ? -1 : 0; /* if showmorph == -1, write intermediate * images to /tmp/seq_output_1.pdf */ pixb = pixConvertTo1(pixs, threshold); pixb2 = pixScale(pixb, 0.5, 0.5); pixseed = pixMorphSequence(pixb2, "o1.2 + c9.9 + o3.5", flag); pixsf = pixSeedfillBinary(NULL, pixseed, pixb2, 8); pixSetOrClearBorder(pixsf, 10, 10, 10, 10, PIX_SET); pixm = pixRemoveBorderConnComps(pixsf, 8); if (display) pixDisplay(pixm, 100, 100); /* Now, where is the main block of text? We want to remove noise near * the edge of the image, but to do that, we have to be convinced that * (1) there is noise and (2) it is far enough from the text block * and close enough to the edge. For each edge, if the block * is more than mindist from that edge, then clean 'erasedist' * pixels from the edge. */ pix1 = pixMorphSequence(pixm, "c50.50", flag - 1); ba1 = pixConnComp(pix1, NULL, 8); ba2 = boxaSort(ba1, L_SORT_BY_AREA, L_SORT_DECREASING, NULL); pixGetDimensions(pix1, &w, &h, NULL); nbox = boxaGetCount(ba2); if (nbox > 1) { box = boxaGetBox(ba2, 0, L_CLONE); boxGetGeometry(box, &bx, &by, &bw, &bh); left = (bx > mindist) ? erasedist : 0; right = (w - bx - bw > mindist) ? erasedist : 0; top = (by > mindist) ? erasedist : 0; bottom = (h - by - bh > mindist) ? erasedist : 0; pixSetOrClearBorder(pixm, left, right, top, bottom, PIX_CLR); boxDestroy(&box); } pixDestroy(&pix1); boxaDestroy(&ba1); boxaDestroy(&ba2); /* Locate the foreground region; don't bother cropping */ pixClipToForeground(pixm, NULL, &boxfg); /* Sanity check the fg region. Make sure it's not confined * to a thin boundary on the left and right sides of the image, * in which case it is likely to be noise. */ if (boxfg) { boxin = boxCreate(0.1 * w, 0, 0.8 * w, h); boxIntersects(boxfg, boxin, &intersects); if (!intersects) { L_INFO("found only noise on page %d\n", procName, pagenum); boxDestroy(&boxfg); } boxDestroy(&boxin); } boxd = NULL; if (!boxfg) { L_INFO("no fg region found for page %d\n", procName, pagenum); } else { boxAdjustSides(boxfg, boxfg, -2, 2, -2, 2); /* tiny expansion */ boxd = boxTransform(boxfg, 0, 0, 2.0, 2.0); /* Write image showing box for this page. This is to be * bundled up into a pdf of all the pages, which can be * generated by convertFilesToPdf() */ if (pdfdir) { pixg2 = pixConvert1To4Cmap(pixb); pixRenderBoxArb(pixg2, boxd, 3, 255, 0, 0); snprintf(buf, sizeof(buf), "/tmp/%s/%05d.png", pdfdir, pagenum); if (display) pixDisplay(pixg2, 700, 100); pixWrite(buf, pixg2, IFF_PNG); pixDestroy(&pixg2); } } pixDestroy(&pixb); pixDestroy(&pixb2); pixDestroy(&pixseed); pixDestroy(&pixsf); pixDestroy(&pixm); boxDestroy(&boxfg); return boxd; }