/********************************************************************** * File: makerow.cpp (Formerly makerows.c) * Description: Code to arrange blobs into rows of text. * Author: Ray Smith * Created: Mon Sep 21 14:34:48 BST 1992 * * (C) Copyright 1992, Hewlett-Packard Ltd. ** Licensed under the Apache License, Version 2.0 (the "License"); ** you may not use this file except in compliance with the License. ** You may obtain a copy of the License at ** http://www.apache.org/licenses/LICENSE-2.0 ** Unless required by applicable law or agreed to in writing, software ** distributed under the License is distributed on an "AS IS" BASIS, ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. ** See the License for the specific language governing permissions and ** limitations under the License. * **********************************************************************/ #ifdef __UNIX__ #include #endif #include "stderr.h" #include "blobbox.h" #include "ccstruct.h" #include "detlinefit.h" #include "statistc.h" #include "drawtord.h" #include "blkocc.h" #include "sortflts.h" #include "oldbasel.h" #include "textord.h" #include "tordmain.h" #include "underlin.h" #include "makerow.h" #include "tprintf.h" #include "tovars.h" // Include automatically generated configuration file if running autoconf. #ifdef HAVE_CONFIG_H #include "config_auto.h" #endif BOOL_VAR(textord_heavy_nr, FALSE, "Vigorously remove noise"); BOOL_VAR(textord_show_initial_rows, FALSE, "Display row accumulation"); BOOL_VAR(textord_show_parallel_rows, FALSE, "Display page correlated rows"); BOOL_VAR(textord_show_expanded_rows, FALSE, "Display rows after expanding"); BOOL_VAR(textord_show_final_rows, FALSE, "Display rows after final fitting"); BOOL_VAR(textord_show_final_blobs, FALSE, "Display blob bounds after pre-ass"); BOOL_VAR(textord_test_landscape, FALSE, "Tests refer to land/port"); BOOL_VAR(textord_parallel_baselines, TRUE, "Force parallel baselines"); BOOL_VAR(textord_straight_baselines, FALSE, "Force straight baselines"); BOOL_VAR(textord_old_baselines, TRUE, "Use old baseline algorithm"); BOOL_VAR(textord_old_xheight, FALSE, "Use old xheight algorithm"); BOOL_VAR(textord_fix_xheight_bug, TRUE, "Use spline baseline"); BOOL_VAR(textord_fix_makerow_bug, TRUE, "Prevent multiple baselines"); BOOL_VAR(textord_debug_xheights, FALSE, "Test xheight algorithms"); BOOL_VAR(textord_biased_skewcalc, TRUE, "Bias skew estimates with line length"); BOOL_VAR(textord_interpolating_skew, TRUE, "Interpolate across gaps"); INT_VAR(textord_skewsmooth_offset, 4, "For smooth factor"); INT_VAR(textord_skewsmooth_offset2, 1, "For smooth factor"); INT_VAR(textord_test_x, -MAX_INT32, "coord of test pt"); INT_VAR(textord_test_y, -MAX_INT32, "coord of test pt"); INT_VAR(textord_min_blobs_in_row, 4, "Min blobs before gradient counted"); INT_VAR(textord_spline_minblobs, 8, "Min blobs in each spline segment"); INT_VAR(textord_spline_medianwin, 6, "Size of window for spline segmentation"); INT_VAR(textord_max_blob_overlaps, 4, "Max number of blobs a big blob can overlap"); INT_VAR(textord_min_xheight, 10, "Min credible pixel xheight"); double_VAR(textord_spline_shift_fraction, 0.02, "Fraction of line spacing for quad"); double_VAR(textord_spline_outlier_fraction, 0.1, "Fraction of line spacing for outlier"); double_VAR(textord_skew_ile, 0.5, "Ile of gradients for page skew"); double_VAR(textord_skew_lag, 0.02, "Lag for skew on row accumulation"); double_VAR(textord_linespace_iqrlimit, 0.2, "Max iqr/median for linespace"); double_VAR(textord_width_limit, 8, "Max width of blobs to make rows"); double_VAR(textord_chop_width, 1.5, "Max width before chopping"); double_VAR(textord_expansion_factor, 1.0, "Factor to expand rows by in expand_rows"); double_VAR(textord_overlap_x, 0.375, "Fraction of linespace for good overlap"); double_VAR(textord_minxh, 0.25, "fraction of linesize for min xheight"); double_VAR(textord_min_linesize, 1.25, "* blob height for initial linesize"); double_VAR(textord_excess_blobsize, 1.3, "New row made if blob makes row this big"); double_VAR(textord_occupancy_threshold, 0.4, "Fraction of neighbourhood"); double_VAR(textord_underline_width, 2.0, "Multiple of line_size for underline"); double_VAR(textord_min_blob_height_fraction, 0.75, "Min blob height/top to include blob top into xheight stats"); double_VAR(textord_xheight_mode_fraction, 0.4, "Min pile height to make xheight"); double_VAR(textord_ascheight_mode_fraction, 0.08, "Min pile height to make ascheight"); double_VAR(textord_descheight_mode_fraction, 0.08, "Min pile height to make descheight"); double_VAR(textord_ascx_ratio_min, 1.25, "Min cap/xheight"); double_VAR(textord_ascx_ratio_max, 1.8, "Max cap/xheight"); double_VAR(textord_descx_ratio_min, 0.25, "Min desc/xheight"); double_VAR(textord_descx_ratio_max, 0.6, "Max desc/xheight"); double_VAR(textord_xheight_error_margin, 0.1, "Accepted variation"); INT_VAR(textord_lms_line_trials, 12, "Number of linew fits to do"); BOOL_VAR(textord_new_initial_xheight, TRUE, "Use test xheight mechanism"); BOOL_VAR(textord_debug_blob, FALSE, "Print test blob information"); #define MAX_HEIGHT_MODES 12 const int kMinLeaderCount = 5; // Factored-out helper to build a single row from a list of blobs. // Returns the mean blob size. static float MakeRowFromBlobs(float line_size, BLOBNBOX_IT* blob_it, TO_ROW_IT* row_it) { blob_it->sort(blob_x_order); blob_it->move_to_first(); TO_ROW* row = NULL; float total_size = 0.0f; int blob_count = 0; // Add all the blobs to a single TO_ROW. for (; !blob_it->empty(); blob_it->forward()) { BLOBNBOX* blob = blob_it->extract(); int top = blob->bounding_box().top(); int bottom = blob->bounding_box().bottom(); if (row == NULL) { row = new TO_ROW(blob, top, bottom, line_size); row_it->add_before_then_move(row); } else { row->add_blob(blob, top, bottom, line_size); } total_size += top - bottom; ++blob_count; } return blob_count > 0 ? total_size / blob_count : total_size; } // Helper to make a row using the children of a single blob. // Returns the mean size of the blobs created. float MakeRowFromSubBlobs(TO_BLOCK* block, C_BLOB* blob, TO_ROW_IT* row_it) { // The blobs made from the children will go in the small_blobs list. BLOBNBOX_IT bb_it(&block->small_blobs); C_OUTLINE_IT ol_it(blob->out_list()); // Get the children. ol_it.set_to_list(ol_it.data()->child()); if (ol_it.empty()) return 0.0f; for (ol_it.mark_cycle_pt(); !ol_it.cycled_list(); ol_it.forward()) { // Deep copy the child outline and use that to make a blob. C_BLOB* blob = new C_BLOB(C_OUTLINE::deep_copy(ol_it.data())); // Correct direction as needed. blob->CheckInverseFlagAndDirection(); BLOBNBOX* bbox = new BLOBNBOX(blob); bb_it.add_after_then_move(bbox); } // Now we can make a row from the blobs. return MakeRowFromBlobs(block->line_size, &bb_it, row_it); } /** * @name make_single_row * * Arrange the blobs into a single row... well actually, if there is * only a single blob, it makes 2 rows, in case the top-level blob * is a container of the real blobs to recognize. */ float make_single_row(ICOORD page_tr, bool allow_sub_blobs, TO_BLOCK* block, TO_BLOCK_LIST* blocks) { BLOBNBOX_IT blob_it = &block->blobs; TO_ROW_IT row_it = block->get_rows(); // Include all the small blobs and large blobs. blob_it.add_list_after(&block->small_blobs); blob_it.add_list_after(&block->noise_blobs); blob_it.add_list_after(&block->large_blobs); if (block->blobs.singleton() && allow_sub_blobs) { blob_it.move_to_first(); float size = MakeRowFromSubBlobs(block, blob_it.data()->cblob(), &row_it); if (size > block->line_size) block->line_size = size; } else if (block->blobs.empty()) { // Make a fake blob. C_BLOB* blob = C_BLOB::FakeBlob(block->block->bounding_box()); // The blobnbox owns the blob. BLOBNBOX* bblob = new BLOBNBOX(blob); blob_it.add_after_then_move(bblob); } MakeRowFromBlobs(block->line_size, &blob_it, &row_it); // Fit an LMS line to the rows. for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) fit_lms_line(row_it.data()); float gradient; float fit_error; // Compute the skew based on the fitted line. compute_page_skew(blocks, gradient, fit_error); return gradient; } /** * @name make_rows * * Arrange the blobs into rows. */ float make_rows(ICOORD page_tr, TO_BLOCK_LIST *port_blocks) { float port_m; // global skew float port_err; // global noise TO_BLOCK_IT block_it; // iterator block_it.set_to_list(port_blocks); for (block_it.mark_cycle_pt(); !block_it.cycled_list(); block_it.forward()) make_initial_textrows(page_tr, block_it.data(), FCOORD(1.0f, 0.0f), !(BOOL8) textord_test_landscape); // compute globally compute_page_skew(port_blocks, port_m, port_err); block_it.set_to_list(port_blocks); for (block_it.mark_cycle_pt(); !block_it.cycled_list(); block_it.forward()) { cleanup_rows_making(page_tr, block_it.data(), port_m, FCOORD(1.0f, 0.0f), block_it.data()->block->bounding_box().left(), !(BOOL8)textord_test_landscape); } return port_m; // global skew } /** * @name make_initial_textrows * * Arrange the good blobs into rows of text. */ void make_initial_textrows( //find lines ICOORD page_tr, TO_BLOCK *block, //block to do FCOORD rotation, //for drawing BOOL8 testing_on //correct orientation ) { TO_ROW_IT row_it = block->get_rows (); #ifndef GRAPHICS_DISABLED ScrollView::Color colour; //of row if (textord_show_initial_rows && testing_on) { if (to_win == NULL) create_to_win(page_tr); } #endif //guess skew assign_blobs_to_rows (block, NULL, 0, TRUE, TRUE, textord_show_initial_rows && testing_on); row_it.move_to_first (); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) fit_lms_line (row_it.data ()); #ifndef GRAPHICS_DISABLED if (textord_show_initial_rows && testing_on) { colour = ScrollView::RED; for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { plot_to_row (row_it.data (), colour, rotation); colour = (ScrollView::Color) (colour + 1); if (colour > ScrollView::MAGENTA) colour = ScrollView::RED; } } #endif } /** * @name fit_lms_line * * Fit an LMS line to a row. */ void fit_lms_line(TO_ROW *row) { float m, c; // fitted line tesseract::DetLineFit lms; BLOBNBOX_IT blob_it = row->blob_list(); for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) { const TBOX& box = blob_it.data()->bounding_box(); lms.Add(ICOORD((box.left() + box.right()) / 2, box.bottom())); } double error = lms.Fit(&m, &c); row->set_line(m, c, error); } /** * @name compute_page_skew * * Compute the skew over a full page by averaging the gradients over * all the lines. Get the error of the same row. */ void compute_page_skew( //get average gradient TO_BLOCK_LIST *blocks, //list of blocks float &page_m, //average gradient float &page_err //average error ) { inT32 row_count; //total rows inT32 blob_count; //total_blobs inT32 row_err; //integer error float *gradients; //of rows float *errors; //of rows inT32 row_index; //of total TO_ROW *row; //current row TO_BLOCK_IT block_it = blocks; //iterator TO_ROW_IT row_it; row_count = 0; blob_count = 0; for (block_it.mark_cycle_pt (); !block_it.cycled_list (); block_it.forward ()) { POLY_BLOCK* pb = block_it.data()->block->poly_block(); if (pb != NULL && !pb->IsText()) continue; // Pretend non-text blocks don't exist. row_count += block_it.data ()->get_rows ()->length (); //count up rows row_it.set_to_list (block_it.data ()->get_rows ()); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) blob_count += row_it.data ()->blob_list ()->length (); } if (row_count == 0) { page_m = 0.0f; page_err = 0.0f; return; } gradients = (float *) alloc_mem (blob_count * sizeof (float)); //get mem errors = (float *) alloc_mem (blob_count * sizeof (float)); if (gradients == NULL || errors == NULL) MEMORY_OUT.error ("compute_page_skew", ABORT, NULL); row_index = 0; for (block_it.mark_cycle_pt (); !block_it.cycled_list (); block_it.forward ()) { POLY_BLOCK* pb = block_it.data()->block->poly_block(); if (pb != NULL && !pb->IsText()) continue; // Pretend non-text blocks don't exist. row_it.set_to_list (block_it.data ()->get_rows ()); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { row = row_it.data (); blob_count = row->blob_list ()->length (); row_err = (inT32) ceil (row->line_error ()); if (row_err <= 0) row_err = 1; if (textord_biased_skewcalc) { blob_count /= row_err; for (blob_count /= row_err; blob_count > 0; blob_count--) { gradients[row_index] = row->line_m (); errors[row_index] = row->line_error (); row_index++; } } else if (blob_count >= textord_min_blobs_in_row) { //get gradient gradients[row_index] = row->line_m (); errors[row_index] = row->line_error (); row_index++; } } } if (row_index == 0) { //desperate for (block_it.mark_cycle_pt (); !block_it.cycled_list (); block_it.forward ()) { POLY_BLOCK* pb = block_it.data()->block->poly_block(); if (pb != NULL && !pb->IsText()) continue; // Pretend non-text blocks don't exist. row_it.set_to_list (block_it.data ()->get_rows ()); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { row = row_it.data (); gradients[row_index] = row->line_m (); errors[row_index] = row->line_error (); row_index++; } } } row_count = row_index; row_index = choose_nth_item ((inT32) (row_count * textord_skew_ile), gradients, row_count); page_m = gradients[row_index]; row_index = choose_nth_item ((inT32) (row_count * textord_skew_ile), errors, row_count); page_err = errors[row_index]; free_mem(gradients); free_mem(errors); } const double kNoiseSize = 0.5; // Fraction of xheight. const int kMinSize = 8; // Min pixels to be xheight. /** * Return true if the dot looks like it is part of the i. * Doesn't work for any other diacritical. */ static bool dot_of_i(BLOBNBOX* dot, BLOBNBOX* i, TO_ROW* row) { const TBOX& ibox = i->bounding_box(); const TBOX& dotbox = dot->bounding_box(); // Must overlap horizontally by enough and be high enough. int overlap = MIN(dotbox.right(), ibox.right()) - MAX(dotbox.left(), ibox.left()); if (ibox.height() <= 2 * dotbox.height() || (overlap * 2 < ibox.width() && overlap < dotbox.width())) return false; // If the i is tall and thin then it is good. if (ibox.height() > ibox.width() * 2) return true; // The i or ! must be tall and thin. // It might still be tall and thin, but it might be joined to something. // So search the outline for a piece of large height close to the edges // of the dot. const double kHeightFraction = 0.6; double target_height = MIN(dotbox.bottom(), ibox.top()); target_height -= row->line_m()*dotbox.left() + row->line_c(); target_height *= kHeightFraction; int left_min = dotbox.left() - dotbox.width(); int middle = (dotbox.left() + dotbox.right())/2; int right_max = dotbox.right() + dotbox.width(); int left_miny = 0; int left_maxy = 0; int right_miny = 0; int right_maxy = 0; bool found_left = false; bool found_right = false; bool in_left = false; bool in_right = false; C_BLOB* blob = i->cblob(); C_OUTLINE_IT o_it = blob->out_list(); for (o_it.mark_cycle_pt(); !o_it.cycled_list(); o_it.forward()) { C_OUTLINE* outline = o_it.data(); int length = outline->pathlength(); ICOORD pos = outline->start_pos(); for (int step = 0; step < length; pos += outline->step(step++)) { int x = pos.x(); int y = pos.y(); if (x >= left_min && x < middle && !found_left) { // We are in the left part so find min and max y. if (in_left) { if (y > left_maxy) left_maxy = y; if (y < left_miny) left_miny = y; } else { left_maxy = left_miny = y; in_left = true; } } else if (in_left) { // We just left the left so look for size. if (left_maxy - left_miny > target_height) { if (found_right) return true; found_left = true; } in_left = false; } if (x <= right_max && x > middle && !found_right) { // We are in the right part so find min and max y. if (in_right) { if (y > right_maxy) right_maxy = y; if (y < right_miny) right_miny = y; } else { right_maxy = right_miny = y; in_right = true; } } else if (in_right) { // We just left the right so look for size. if (right_maxy - right_miny > target_height) { if (found_left) return true; found_right = true; } in_right = false; } } } return false; } void vigorous_noise_removal(TO_BLOCK* block) { TO_ROW_IT row_it = block->get_rows (); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { TO_ROW* row = row_it.data(); BLOBNBOX_IT b_it = row->blob_list(); // Estimate the xheight on the row. int max_height = 0; for (b_it.mark_cycle_pt(); !b_it.cycled_list(); b_it.forward()) { BLOBNBOX* blob = b_it.data(); if (blob->bounding_box().height() > max_height) max_height = blob->bounding_box().height(); } STATS hstats(0, max_height + 1); for (b_it.mark_cycle_pt(); !b_it.cycled_list(); b_it.forward()) { BLOBNBOX* blob = b_it.data(); int height = blob->bounding_box().height(); if (height >= kMinSize) hstats.add(blob->bounding_box().height(), 1); } float xheight = hstats.median(); // Delete small objects. BLOBNBOX* prev = NULL; for (b_it.mark_cycle_pt(); !b_it.cycled_list(); b_it.forward()) { BLOBNBOX* blob = b_it.data(); const TBOX& box = blob->bounding_box(); if (box.height() < kNoiseSize * xheight) { // Small so delete unless it looks like an i dot. if (prev != NULL) { if (dot_of_i(blob, prev, row)) continue; // Looks OK. } if (!b_it.at_last()) { BLOBNBOX* next = b_it.data_relative(1); if (dot_of_i(blob, next, row)) continue; // Looks OK. } // It might be noise so get rid of it. delete blob->cblob(); delete b_it.extract(); } else { prev = blob; } } } } /** * cleanup_rows_making * * Remove overlapping rows and fit all the blobs to what's left. */ void cleanup_rows_making( //find lines ICOORD page_tr, //top right TO_BLOCK *block, //block to do float gradient, //gradient to fit FCOORD rotation, //for drawing inT32 block_edge, //edge of block BOOL8 testing_on //correct orientation ) { //iterators BLOBNBOX_IT blob_it = &block->blobs; TO_ROW_IT row_it = block->get_rows (); #ifndef GRAPHICS_DISABLED if (textord_show_parallel_rows && testing_on) { if (to_win == NULL) create_to_win(page_tr); } #endif //get row coords fit_parallel_rows(block, gradient, rotation, block_edge, textord_show_parallel_rows &&testing_on); delete_non_dropout_rows(block, gradient, rotation, block_edge, textord_show_parallel_rows &&testing_on); expand_rows(page_tr, block, gradient, rotation, block_edge, testing_on); blob_it.set_to_list (&block->blobs); row_it.set_to_list (block->get_rows ()); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) blob_it.add_list_after (row_it.data ()->blob_list ()); //give blobs back assign_blobs_to_rows (block, &gradient, 1, FALSE, FALSE, FALSE); //now new rows must be genuine blob_it.set_to_list (&block->blobs); blob_it.add_list_after (&block->large_blobs); assign_blobs_to_rows (block, &gradient, 2, TRUE, TRUE, FALSE); //safe to use big ones now blob_it.set_to_list (&block->blobs); //throw all blobs in blob_it.add_list_after (&block->noise_blobs); blob_it.add_list_after (&block->small_blobs); assign_blobs_to_rows (block, &gradient, 3, FALSE, FALSE, FALSE); } /** * delete_non_dropout_rows * * Compute the linespacing and offset. */ void delete_non_dropout_rows( //find lines TO_BLOCK *block, //block to do float gradient, //global skew FCOORD rotation, //deskew vector inT32 block_edge, //left edge BOOL8 testing_on //correct orientation ) { TBOX block_box; //deskewed block inT32 *deltas; //change in occupation inT32 *occupation; //of pixel coords inT32 max_y; //in block inT32 min_y; inT32 line_index; //of scan line inT32 line_count; //no of scan lines inT32 distance; //to drop-out inT32 xleft; //of block inT32 ybottom; //of block TO_ROW *row; //current row TO_ROW_IT row_it = block->get_rows (); BLOBNBOX_IT blob_it = &block->blobs; if (row_it.length () == 0) return; //empty block block_box = deskew_block_coords (block, gradient); xleft = block->block->bounding_box ().left (); ybottom = block->block->bounding_box ().bottom (); min_y = block_box.bottom () - 1; max_y = block_box.top () + 1; for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { line_index = (inT32) floor (row_it.data ()->intercept ()); if (line_index <= min_y) min_y = line_index - 1; if (line_index >= max_y) max_y = line_index + 1; } line_count = max_y - min_y + 1; if (line_count <= 0) return; //empty block deltas = (inT32 *) alloc_mem (line_count * sizeof (inT32)); occupation = (inT32 *) alloc_mem (line_count * sizeof (inT32)); if (deltas == NULL || occupation == NULL) MEMORY_OUT.error ("compute_line_spacing", ABORT, NULL); compute_line_occupation(block, gradient, min_y, max_y, occupation, deltas); compute_occupation_threshold ((inT32) ceil (block->line_spacing * (tesseract::CCStruct::kDescenderFraction + tesseract::CCStruct::kAscenderFraction)), (inT32) ceil (block->line_spacing * (tesseract::CCStruct::kXHeightFraction + tesseract::CCStruct::kAscenderFraction)), max_y - min_y + 1, occupation, deltas); #ifndef GRAPHICS_DISABLED if (testing_on) { draw_occupation(xleft, ybottom, min_y, max_y, occupation, deltas); } #endif compute_dropout_distances(occupation, deltas, line_count); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { row = row_it.data (); line_index = (inT32) floor (row->intercept ()); distance = deltas[line_index - min_y]; if (find_best_dropout_row (row, distance, block->line_spacing / 2, line_index, &row_it, testing_on)) { #ifndef GRAPHICS_DISABLED if (testing_on) plot_parallel_row(row, gradient, block_edge, ScrollView::WHITE, rotation); #endif blob_it.add_list_after (row_it.data ()->blob_list ()); delete row_it.extract (); //too far away } } for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { blob_it.add_list_after (row_it.data ()->blob_list ()); } free_mem(deltas); free_mem(occupation); } /** * @name find_best_dropout_row * * Delete this row if it has a neighbour with better dropout characteristics. * TRUE is returned if the row should be deleted. */ BOOL8 find_best_dropout_row( //find neighbours TO_ROW *row, //row to test inT32 distance, //dropout dist float dist_limit, //threshold distance inT32 line_index, //index of row TO_ROW_IT *row_it, //current position BOOL8 testing_on //correct orientation ) { inT32 next_index; // of neighbouring row inT32 row_offset; //from current row inT32 abs_dist; //absolute distance inT8 row_inc; //increment to row_index TO_ROW *next_row; //nextious row if (testing_on) tprintf ("Row at %g(%g), dropout dist=%d,", row->intercept (), row->parallel_c (), distance); if (distance < 0) { row_inc = 1; abs_dist = -distance; } else { row_inc = -1; abs_dist = distance; } if (abs_dist > dist_limit) { if (testing_on) { tprintf (" too far - deleting\n"); } return TRUE; } if ((distance < 0 && !row_it->at_last ()) || (distance >= 0 && !row_it->at_first ())) { row_offset = row_inc; do { next_row = row_it->data_relative (row_offset); next_index = (inT32) floor (next_row->intercept ()); if ((distance < 0 && next_index < line_index && next_index > line_index + distance + distance) || (distance >= 0 && next_index > line_index && next_index < line_index + distance + distance)) { if (testing_on) { tprintf (" nearer neighbour (%d) at %g\n", line_index + distance - next_index, next_row->intercept ()); } return TRUE; //other is nearer } else if (next_index == line_index || next_index == line_index + distance + distance) { if (row->believability () <= next_row->believability ()) { if (testing_on) { tprintf (" equal but more believable at %g (%g/%g)\n", next_row->intercept (), row->believability (), next_row->believability ()); } return TRUE; //other is more believable } } row_offset += row_inc; } while ((next_index == line_index || next_index == line_index + distance + distance) && row_offset < row_it->length ()); if (testing_on) tprintf (" keeping\n"); } return FALSE; } /** * @name deskew_block_coords * * Compute the bounding box of all the blobs in the block * if they were deskewed without actually doing it. */ TBOX deskew_block_coords( //block box TO_BLOCK *block, //block to do float gradient //global skew ) { TBOX result; //block bounds TBOX blob_box; //of block FCOORD rotation; //deskew vector float length; //of gradient vector TO_ROW_IT row_it = block->get_rows (); TO_ROW *row; //current row BLOBNBOX *blob; //current blob BLOBNBOX_IT blob_it; //iterator length = sqrt (gradient * gradient + 1); rotation = FCOORD (1 / length, -gradient / length); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { row = row_it.data (); blob_it.set_to_list (row->blob_list ()); for (blob_it.mark_cycle_pt (); !blob_it.cycled_list (); blob_it.forward ()) { blob = blob_it.data (); blob_box = blob->bounding_box (); blob_box.rotate (rotation);//de-skew it result += blob_box; } } return result; } /** * @name compute_line_occupation * * Compute the pixel projection back on the y axis given the global * skew. Also compute the 1st derivative. */ void compute_line_occupation( //project blobs TO_BLOCK *block, //block to do float gradient, //global skew inT32 min_y, //min coord in block inT32 max_y, //in block inT32 *occupation, //output projection inT32 *deltas //derivative ) { inT32 line_count; //maxy-miny+1 inT32 line_index; //of scan line int index; //array index for daft compilers TO_ROW *row; //current row TO_ROW_IT row_it = block->get_rows (); BLOBNBOX *blob; //current blob BLOBNBOX_IT blob_it; //iterator float length; //of skew vector TBOX blob_box; //bounding box FCOORD rotation; //inverse of skew line_count = max_y - min_y + 1; length = sqrt (gradient * gradient + 1); rotation = FCOORD (1 / length, -gradient / length); for (line_index = 0; line_index < line_count; line_index++) deltas[line_index] = 0; for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { row = row_it.data (); blob_it.set_to_list (row->blob_list ()); for (blob_it.mark_cycle_pt (); !blob_it.cycled_list (); blob_it.forward ()) { blob = blob_it.data (); blob_box = blob->bounding_box (); blob_box.rotate (rotation);//de-skew it int32_t width = blob_box.right() - blob_box.left(); index = blob_box.bottom() - min_y; ASSERT_HOST(index >= 0 && index < line_count); // count transitions deltas[index] += width; index = blob_box.top() - min_y; ASSERT_HOST(index >= 0 && index < line_count); deltas[index] -= width; } } occupation[0] = deltas[0]; for (line_index = 1; line_index < line_count; line_index++) occupation[line_index] = occupation[line_index - 1] + deltas[line_index]; } /** * compute_occupation_threshold * * Compute thresholds for textline or not for the occupation array. */ void compute_occupation_threshold( //project blobs inT32 low_window, //below result point inT32 high_window, //above result point inT32 line_count, //array sizes inT32 *occupation, //input projection inT32 *thresholds //output thresholds ) { inT32 line_index; //of thresholds line inT32 low_index; //in occupation inT32 high_index; //in occupation inT32 sum; //current average inT32 divisor; //to get thresholds inT32 min_index; //of min occ inT32 min_occ; //min in locality inT32 test_index; //for finding min divisor = (inT32) ceil ((low_window + high_window) / textord_occupancy_threshold); if (low_window + high_window < line_count) { for (sum = 0, high_index = 0; high_index < low_window; high_index++) sum += occupation[high_index]; for (low_index = 0; low_index < high_window; low_index++, high_index++) sum += occupation[high_index]; min_occ = occupation[0]; min_index = 0; for (test_index = 1; test_index < high_index; test_index++) { if (occupation[test_index] <= min_occ) { min_occ = occupation[test_index]; min_index = test_index; //find min in region } } for (line_index = 0; line_index < low_window; line_index++) thresholds[line_index] = (sum - min_occ) / divisor + min_occ; //same out to end for (low_index = 0; high_index < line_count; low_index++, high_index++) { sum -= occupation[low_index]; sum += occupation[high_index]; if (occupation[high_index] <= min_occ) { //find min in region min_occ = occupation[high_index]; min_index = high_index; } //lost min from region if (min_index <= low_index) { min_occ = occupation[low_index + 1]; min_index = low_index + 1; for (test_index = low_index + 2; test_index <= high_index; test_index++) { if (occupation[test_index] <= min_occ) { min_occ = occupation[test_index]; //find min in region min_index = test_index; } } } thresholds[line_index++] = (sum - min_occ) / divisor + min_occ; } } else { min_occ = occupation[0]; min_index = 0; for (sum = 0, low_index = 0; low_index < line_count; low_index++) { if (occupation[low_index] < min_occ) { min_occ = occupation[low_index]; min_index = low_index; } sum += occupation[low_index]; } line_index = 0; } for (; line_index < line_count; line_index++) thresholds[line_index] = (sum - min_occ) / divisor + min_occ; //same out to end } /** * @name compute_dropout_distances * * Compute the distance from each coordinate to the nearest dropout. */ void compute_dropout_distances( //project blobs inT32 *occupation, //input projection inT32 *thresholds, //output thresholds inT32 line_count //array sizes ) { inT32 line_index; //of thresholds line inT32 distance; //from prev dropout inT32 next_dist; //to next dropout inT32 back_index; //for back filling inT32 prev_threshold; //before overwrite distance = -line_count; line_index = 0; do { do { distance--; prev_threshold = thresholds[line_index]; //distance from prev thresholds[line_index] = distance; line_index++; } while (line_index < line_count && (occupation[line_index] < thresholds[line_index] || occupation[line_index - 1] >= prev_threshold)); if (line_index < line_count) { back_index = line_index - 1; next_dist = 1; while (next_dist < -distance && back_index >= 0) { thresholds[back_index] = next_dist; back_index--; next_dist++; distance++; } distance = 1; } } while (line_index < line_count); } /** * @name expand_rows * * Expand each row to the least of its allowed size and touching its * neighbours. If the expansion would entirely swallow a neighbouring row * then do so. */ void expand_rows( //find lines ICOORD page_tr, //top right TO_BLOCK *block, //block to do float gradient, //gradient to fit FCOORD rotation, //for drawing inT32 block_edge, //edge of block BOOL8 testing_on //correct orientation ) { BOOL8 swallowed_row; //eaten a neighbour float y_max, y_min; //new row limits float y_bottom, y_top; //allowed limits TO_ROW *test_row; //next row TO_ROW *row; //current row //iterators BLOBNBOX_IT blob_it = &block->blobs; TO_ROW_IT row_it = block->get_rows (); #ifndef GRAPHICS_DISABLED if (textord_show_expanded_rows && testing_on) { if (to_win == NULL) create_to_win(page_tr); } #endif adjust_row_limits(block); //shift min,max. if (textord_new_initial_xheight) { if (block->get_rows ()->length () == 0) return; compute_row_stats(block, textord_show_expanded_rows &&testing_on); } assign_blobs_to_rows (block, &gradient, 4, TRUE, FALSE, FALSE); //get real membership if (block->get_rows ()->length () == 0) return; fit_parallel_rows(block, gradient, rotation, block_edge, textord_show_expanded_rows &&testing_on); if (!textord_new_initial_xheight) compute_row_stats(block, textord_show_expanded_rows &&testing_on); row_it.move_to_last (); do { row = row_it.data (); y_max = row->max_y (); //get current limits y_min = row->min_y (); y_bottom = row->intercept () - block->line_size * textord_expansion_factor * tesseract::CCStruct::kDescenderFraction; y_top = row->intercept () + block->line_size * textord_expansion_factor * (tesseract::CCStruct::kXHeightFraction + tesseract::CCStruct::kAscenderFraction); if (y_min > y_bottom) { //expansion allowed if (textord_show_expanded_rows && testing_on) tprintf("Expanding bottom of row at %f from %f to %f\n", row->intercept(), y_min, y_bottom); //expandable swallowed_row = TRUE; while (swallowed_row && !row_it.at_last ()) { swallowed_row = FALSE; //get next one test_row = row_it.data_relative (1); //overlaps space if (test_row->max_y () > y_bottom) { if (test_row->min_y () > y_bottom) { if (textord_show_expanded_rows && testing_on) tprintf("Eating row below at %f\n", test_row->intercept()); row_it.forward (); #ifndef GRAPHICS_DISABLED if (textord_show_expanded_rows && testing_on) plot_parallel_row(test_row, gradient, block_edge, ScrollView::WHITE, rotation); #endif blob_it.set_to_list (row->blob_list ()); blob_it.add_list_after (test_row->blob_list ()); //swallow complete row delete row_it.extract (); row_it.backward (); swallowed_row = TRUE; } else if (test_row->max_y () < y_min) { //shorter limit y_bottom = test_row->max_y (); if (textord_show_expanded_rows && testing_on) tprintf("Truncating limit to %f due to touching row at %f\n", y_bottom, test_row->intercept()); } else { y_bottom = y_min; //can't expand it if (textord_show_expanded_rows && testing_on) tprintf("Not expanding limit beyond %f due to touching row at %f\n", y_bottom, test_row->intercept()); } } } y_min = y_bottom; //expand it } if (y_max < y_top) { //expansion allowed if (textord_show_expanded_rows && testing_on) tprintf("Expanding top of row at %f from %f to %f\n", row->intercept(), y_max, y_top); swallowed_row = TRUE; while (swallowed_row && !row_it.at_first ()) { swallowed_row = FALSE; //get one above test_row = row_it.data_relative (-1); if (test_row->min_y () < y_top) { if (test_row->max_y () < y_top) { if (textord_show_expanded_rows && testing_on) tprintf("Eating row above at %f\n", test_row->intercept()); row_it.backward (); blob_it.set_to_list (row->blob_list ()); #ifndef GRAPHICS_DISABLED if (textord_show_expanded_rows && testing_on) plot_parallel_row(test_row, gradient, block_edge, ScrollView::WHITE, rotation); #endif blob_it.add_list_after (test_row->blob_list ()); //swallow complete row delete row_it.extract (); row_it.forward (); swallowed_row = TRUE; } else if (test_row->min_y () < y_max) { //shorter limit y_top = test_row->min_y (); if (textord_show_expanded_rows && testing_on) tprintf("Truncating limit to %f due to touching row at %f\n", y_top, test_row->intercept()); } else { y_top = y_max; //can't expand it if (textord_show_expanded_rows && testing_on) tprintf("Not expanding limit beyond %f due to touching row at %f\n", y_top, test_row->intercept()); } } } y_max = y_top; } //new limits row->set_limits (y_min, y_max); row_it.backward (); } while (!row_it.at_last ()); } /** * adjust_row_limits * * Change the limits of rows to suit the default fractions. */ void adjust_row_limits( //tidy limits TO_BLOCK *block //block to do ) { TO_ROW *row; //current row float size; //size of row float ymax; //top of row float ymin; //bottom of row TO_ROW_IT row_it = block->get_rows (); if (textord_show_expanded_rows) tprintf("Adjusting row limits for block(%d,%d)\n", block->block->bounding_box().left(), block->block->bounding_box().top()); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { row = row_it.data (); size = row->max_y () - row->min_y (); if (textord_show_expanded_rows) tprintf("Row at %f has min %f, max %f, size %f\n", row->intercept(), row->min_y(), row->max_y(), size); size /= tesseract::CCStruct::kXHeightFraction + tesseract::CCStruct::kAscenderFraction + tesseract::CCStruct::kDescenderFraction; ymax = size * (tesseract::CCStruct::kXHeightFraction + tesseract::CCStruct::kAscenderFraction); ymin = -size * tesseract::CCStruct::kDescenderFraction; row->set_limits (row->intercept () + ymin, row->intercept () + ymax); row->merged = FALSE; } } /** * @name compute_row_stats * * Compute the linespacing and offset. */ void compute_row_stats( //find lines TO_BLOCK *block, //block to do BOOL8 testing_on //correct orientation ) { inT32 row_index; //of median TO_ROW *row; //current row TO_ROW *prev_row; //previous row float iqr; //inter quartile range TO_ROW_IT row_it = block->get_rows (); //number of rows inT16 rowcount = row_it.length (); TO_ROW **rows; //for choose nth rows = (TO_ROW **) alloc_mem (rowcount * sizeof (TO_ROW *)); if (rows == NULL) MEMORY_OUT.error ("compute_row_stats", ABORT, NULL); rowcount = 0; prev_row = NULL; row_it.move_to_last (); //start at bottom do { row = row_it.data (); if (prev_row != NULL) { rows[rowcount++] = prev_row; prev_row->spacing = row->intercept () - prev_row->intercept (); if (testing_on) tprintf ("Row at %g yields spacing of %g\n", row->intercept (), prev_row->spacing); } prev_row = row; row_it.backward (); } while (!row_it.at_last ()); block->key_row = prev_row; block->baseline_offset = fmod (prev_row->parallel_c (), block->line_spacing); if (testing_on) tprintf ("Blob based spacing=(%g,%g), offset=%g", block->line_size, block->line_spacing, block->baseline_offset); if (rowcount > 0) { row_index = choose_nth_item (rowcount * 3 / 4, rows, rowcount, sizeof (TO_ROW *), row_spacing_order); iqr = rows[row_index]->spacing; row_index = choose_nth_item (rowcount / 4, rows, rowcount, sizeof (TO_ROW *), row_spacing_order); iqr -= rows[row_index]->spacing; row_index = choose_nth_item (rowcount / 2, rows, rowcount, sizeof (TO_ROW *), row_spacing_order); block->key_row = rows[row_index]; if (testing_on) tprintf (" row based=%g(%g)", rows[row_index]->spacing, iqr); if (rowcount > 2 && iqr < rows[row_index]->spacing * textord_linespace_iqrlimit) { if (!textord_new_initial_xheight) { if (rows[row_index]->spacing < block->line_spacing && rows[row_index]->spacing > block->line_size) //within range block->line_size = rows[row_index]->spacing; //spacing=size else if (rows[row_index]->spacing > block->line_spacing) block->line_size = block->line_spacing; //too big so use max } else { if (rows[row_index]->spacing < block->line_spacing) block->line_size = rows[row_index]->spacing; else block->line_size = block->line_spacing; //too big so use max } if (block->line_size < textord_min_xheight) block->line_size = (float) textord_min_xheight; block->line_spacing = rows[row_index]->spacing; block->max_blob_size = block->line_spacing * textord_excess_blobsize; } block->baseline_offset = fmod (rows[row_index]->intercept (), block->line_spacing); } if (testing_on) tprintf ("\nEstimate line size=%g, spacing=%g, offset=%g\n", block->line_size, block->line_spacing, block->baseline_offset); free_mem(rows); } /** * @name compute_block_xheight * * Compute the xheight of the individual rows, then correlate them * and interpret ascenderless lines, correcting xheights. * * First we compute our best guess of the x-height of each row independently * with compute_row_xheight(), which looks for a pair of commonly occurring * heights that could be x-height and ascender height. This function also * attempts to find descenders of lowercase letters (i.e. not the small * descenders that could appear in upper case letters as Q,J). * * After this computation each row falls into one of the following categories: * ROW_ASCENDERS_FOUND: we found xheight and ascender modes, so this must be * a regular row; we'll use its xheight to compute * xheight and ascrise estimates for the block * ROW_DESCENDERS_FOUND: no ascenders, so we do not have a high confidence in * the xheight of this row (don't use it for estimating * block xheight), but this row can't contain all caps * ROW_UNKNOWN: a row with no ascenders/descenders, could be all lowercase * (or mostly lowercase for fonts with very few ascenders), * all upper case or small caps * ROW_INVALID: no meaningful xheight could be found for this row * * We then run correct_row_xheight() and use the computed xheight and ascrise * averages to correct xheight values of the rows in ROW_DESCENDERS_FOUND, * ROW_UNKNOWN and ROW_INVALID categories. * */ namespace tesseract { void Textord::compute_block_xheight(TO_BLOCK *block, float gradient) { TO_ROW *row; // current row float asc_frac_xheight = CCStruct::kAscenderFraction / CCStruct::kXHeightFraction; float desc_frac_xheight = CCStruct::kDescenderFraction / CCStruct::kXHeightFraction; inT32 min_height, max_height; // limits on xheight TO_ROW_IT row_it = block->get_rows(); if (row_it.empty()) return; // no rows // Compute the best guess of xheight of each row individually. // Use xheight and ascrise values of the rows where ascenders were found. get_min_max_xheight(block->line_size, &min_height, &max_height); STATS row_asc_xheights(min_height, max_height + 1); STATS row_asc_ascrise(static_cast(min_height * asc_frac_xheight), static_cast(max_height * asc_frac_xheight) + 1); int min_desc_height = static_cast(min_height * desc_frac_xheight); int max_desc_height = static_cast(max_height * desc_frac_xheight); STATS row_asc_descdrop(min_desc_height, max_desc_height + 1); STATS row_desc_xheights(min_height, max_height + 1); STATS row_desc_descdrop(min_desc_height, max_desc_height + 1); STATS row_cap_xheights(min_height, max_height + 1); STATS row_cap_floating_xheights(min_height, max_height + 1); for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) { row = row_it.data(); // Compute the xheight of this row if it has not been computed before. if (row->xheight <= 0.0) { compute_row_xheight(row, block->block->classify_rotation(), gradient, block->line_size); } ROW_CATEGORY row_category = get_row_category(row); if (row_category == ROW_ASCENDERS_FOUND) { row_asc_xheights.add(static_cast(row->xheight), row->xheight_evidence); row_asc_ascrise.add(static_cast(row->ascrise), row->xheight_evidence); row_asc_descdrop.add(static_cast(-row->descdrop), row->xheight_evidence); } else if (row_category == ROW_DESCENDERS_FOUND) { row_desc_xheights.add(static_cast(row->xheight), row->xheight_evidence); row_desc_descdrop.add(static_cast(-row->descdrop), row->xheight_evidence); } else if (row_category == ROW_UNKNOWN) { fill_heights(row, gradient, min_height, max_height, &row_cap_xheights, &row_cap_floating_xheights); } } float xheight = 0.0; float ascrise = 0.0; float descdrop = 0.0; // Compute our best guess of xheight of this block. if (row_asc_xheights.get_total() > 0) { // Determine xheight from rows where ascenders were found. xheight = row_asc_xheights.median(); ascrise = row_asc_ascrise.median(); descdrop = -row_asc_descdrop.median(); } else if (row_desc_xheights.get_total() > 0) { // Determine xheight from rows where descenders were found. xheight = row_desc_xheights.median(); descdrop = -row_desc_descdrop.median(); } else if (row_cap_xheights.get_total() > 0) { // All the rows in the block were (a/de)scenderless. // Try to search for two modes in row_cap_heights that could // be the xheight and the capheight (e.g. some of the rows // were lowercase, but did not have enough (a/de)scenders. // If such two modes can not be found, this block is most // likely all caps (or all small caps, in which case the code // still works as intended). compute_xheight_from_modes(&row_cap_xheights, &row_cap_floating_xheights, textord_single_height_mode && block->block->classify_rotation().y() == 0.0, min_height, max_height, &(xheight), &(ascrise)); if (ascrise == 0) { // assume only caps in the whole block xheight = row_cap_xheights.median() * CCStruct::kXHeightCapRatio; } } else { // default block sizes xheight = block->line_size * CCStruct::kXHeightFraction; } // Correct xheight, ascrise and descdrop if necessary. bool corrected_xheight = false; if (xheight < textord_min_xheight) { xheight = static_cast(textord_min_xheight); corrected_xheight = true; } if (corrected_xheight || ascrise <= 0.0) { ascrise = xheight * asc_frac_xheight; } if (corrected_xheight || descdrop >= 0.0) { descdrop = -(xheight * desc_frac_xheight); } block->xheight = xheight; if (textord_debug_xheights) { tprintf("Block average xheight=%.4f, ascrise=%.4f, descdrop=%.4f\n", xheight, ascrise, descdrop); } // Correct xheight, ascrise, descdrop of rows based on block averages. for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) { correct_row_xheight(row_it.data(), xheight, ascrise, descdrop); } } /** * @name compute_row_xheight * * Estimate the xheight of this row. * Compute the ascender rise and descender drop at the same time. * Set xheigh_evidence to the number of blobs with the chosen xheight * that appear in this row. */ void Textord::compute_row_xheight(TO_ROW *row, // row to do const FCOORD& rotation, float gradient, // global skew int block_line_size) { // Find blobs representing repeated characters in rows and mark them. // This information is used for computing row xheight and at a later // stage when words are formed by make_words. if (!row->rep_chars_marked()) { mark_repeated_chars(row); } int min_height, max_height; get_min_max_xheight(block_line_size, &min_height, &max_height); STATS heights(min_height, max_height + 1); STATS floating_heights(min_height, max_height + 1); fill_heights(row, gradient, min_height, max_height, &heights, &floating_heights); row->ascrise = 0.0f; row->xheight = 0.0f; row->xheight_evidence = compute_xheight_from_modes(&heights, &floating_heights, textord_single_height_mode && rotation.y() == 0.0, min_height, max_height, &(row->xheight), &(row->ascrise)); row->descdrop = 0.0f; if (row->xheight > 0.0) { row->descdrop = static_cast( compute_row_descdrop(row, gradient, row->xheight_evidence, &heights)); } } } // namespace tesseract. /** * @name fill_heights * * Fill the given heights with heights of the blobs that are legal * candidates for estimating xheight. */ void fill_heights(TO_ROW *row, float gradient, int min_height, int max_height, STATS *heights, STATS *floating_heights) { float xcentre; // centre of blob float top; // top y coord of blob float height; // height of blob BLOBNBOX *blob; // current blob int repeated_set; BLOBNBOX_IT blob_it = row->blob_list(); if (blob_it.empty()) return; // no blobs in this row bool has_rep_chars = row->rep_chars_marked() && row->num_repeated_sets() > 0; do { blob = blob_it.data(); if (!blob->joined_to_prev()) { xcentre = (blob->bounding_box().left() + blob->bounding_box().right()) / 2.0f; top = blob->bounding_box().top(); height = blob->bounding_box().height(); if (textord_fix_xheight_bug) top -= row->baseline.y(xcentre); else top -= gradient * xcentre + row->parallel_c(); if (top >= min_height && top <= max_height) { heights->add(static_cast(floor(top + 0.5)), 1); if (height / top < textord_min_blob_height_fraction) { floating_heights->add(static_cast(floor(top + 0.5)), 1); } } } // Skip repeated chars, since they are likely to skew the height stats. if (has_rep_chars && blob->repeated_set() != 0) { repeated_set = blob->repeated_set(); blob_it.forward(); while (!blob_it.at_first() && blob_it.data()->repeated_set() == repeated_set) { blob_it.forward(); if (textord_debug_xheights) tprintf("Skipping repeated char when computing xheight\n"); } } else { blob_it.forward(); } } while (!blob_it.at_first()); } /** * @name compute_xheight_from_modes * * Given a STATS object heights, looks for two most frequently occurring * heights that look like xheight and xheight + ascrise. If found, sets * the values of *xheight and *ascrise accordingly, otherwise sets xheight * to any most frequently occurring height and sets *ascrise to 0. * Returns the number of times xheight occurred in heights. * For each mode that is considered for being an xheight the count of * floating blobs (stored in floating_heights) is subtracted from the * total count of the blobs of this height. This is done because blobs * that sit far above the baseline could represent valid ascenders, but * it is highly unlikely that such a character's height will be an xheight * (e.g. -, ', =, ^, `, ", ', etc) * If cap_only, then force finding of only the top mode. */ int compute_xheight_from_modes( STATS *heights, STATS *floating_heights, bool cap_only, int min_height, int max_height, float *xheight, float *ascrise) { int blob_index = heights->mode(); // find mode int blob_count = heights->pile_count(blob_index); // get count of mode if (textord_debug_xheights) { tprintf("min_height=%d, max_height=%d, mode=%d, count=%d, total=%d\n", min_height, max_height, blob_index, blob_count, heights->get_total()); heights->print(); floating_heights->print(); } if (blob_count == 0) return 0; int modes[MAX_HEIGHT_MODES]; // biggest piles bool in_best_pile = FALSE; int prev_size = -MAX_INT32; int best_count = 0; int mode_count = compute_height_modes(heights, min_height, max_height, modes, MAX_HEIGHT_MODES); if (cap_only && mode_count > 1) mode_count = 1; int x; if (textord_debug_xheights) { tprintf("found %d modes: ", mode_count); for (x = 0; x < mode_count; x++) tprintf("%d ", modes[x]); tprintf("\n"); } for (x = 0; x < mode_count - 1; x++) { if (modes[x] != prev_size + 1) in_best_pile = FALSE; // had empty height int modes_x_count = heights->pile_count(modes[x]) - floating_heights->pile_count(modes[x]); if ((modes_x_count >= blob_count * textord_xheight_mode_fraction) && (in_best_pile || modes_x_count > best_count)) { for (int asc = x + 1; asc < mode_count; asc++) { float ratio = static_cast(modes[asc]) / static_cast(modes[x]); if (textord_ascx_ratio_min < ratio && ratio < textord_ascx_ratio_max && (heights->pile_count(modes[asc]) >= blob_count * textord_ascheight_mode_fraction)) { if (modes_x_count > best_count) { in_best_pile = true; best_count = modes_x_count; } if (textord_debug_xheights) { tprintf("X=%d, asc=%d, count=%d, ratio=%g\n", modes[x], modes[asc]-modes[x], modes_x_count, ratio); } prev_size = modes[x]; *xheight = static_cast(modes[x]); *ascrise = static_cast(modes[asc] - modes[x]); } } } } if (*xheight == 0) { // single mode // Remove counts of the "floating" blobs (the one whose height is too // small in relation to it's top end of the bounding box) from heights // before computing the single-mode xheight. // Restore the counts in heights after the mode is found, since // floating blobs might be useful for determining potential ascenders // in compute_row_descdrop(). if (floating_heights->get_total() > 0) { for (x = min_height; x < max_height; ++x) { heights->add(x, -(floating_heights->pile_count(x))); } blob_index = heights->mode(); // find the modified mode for (x = min_height; x < max_height; ++x) { heights->add(x, floating_heights->pile_count(x)); } } *xheight = static_cast(blob_index); *ascrise = 0.0f; best_count = heights->pile_count(blob_index); if (textord_debug_xheights) tprintf("Single mode xheight set to %g\n", *xheight); } else if (textord_debug_xheights) { tprintf("Multi-mode xheight set to %g, asc=%g\n", *xheight, *ascrise); } return best_count; } /** * @name compute_row_descdrop * * Estimates the descdrop of this row. This function looks for * "significant" descenders of lowercase letters (those that could * not just be the small descenders of upper case letters like Q,J). * The function also takes into account how many potential ascenders * this row might contain. If the number of potential ascenders along * with descenders is close to the expected fraction of the total * number of blobs in the row, the function returns the descender * height, returns 0 otherwise. */ inT32 compute_row_descdrop(TO_ROW *row, float gradient, int xheight_blob_count, STATS *asc_heights) { // Count how many potential ascenders are in this row. int i_min = asc_heights->min_bucket(); if ((i_min / row->xheight) < textord_ascx_ratio_min) { i_min = static_cast( floor(row->xheight * textord_ascx_ratio_min + 0.5)); } int i_max = asc_heights->max_bucket(); if ((i_max / row->xheight) > textord_ascx_ratio_max) { i_max = static_cast(floor(row->xheight * textord_ascx_ratio_max)); } int num_potential_asc = 0; for (int i = i_min; i <= i_max; ++i) { num_potential_asc += asc_heights->pile_count(i); } inT32 min_height = static_cast(floor(row->xheight * textord_descx_ratio_min + 0.5)); inT32 max_height = static_cast(floor(row->xheight * textord_descx_ratio_max)); float xcentre; // centre of blob float height; // height of blob BLOBNBOX_IT blob_it = row->blob_list(); BLOBNBOX *blob; // current blob STATS heights (min_height, max_height + 1); for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) { blob = blob_it.data(); if (!blob->joined_to_prev()) { xcentre = (blob->bounding_box().left() + blob->bounding_box().right()) / 2.0f; height = (gradient * xcentre + row->parallel_c() - blob->bounding_box().bottom()); if (height >= min_height && height <= max_height) heights.add(static_cast(floor(height + 0.5)), 1); } } int blob_index = heights.mode(); // find mode int blob_count = heights.pile_count(blob_index); // get count of mode float total_fraction = (textord_descheight_mode_fraction + textord_ascheight_mode_fraction); if (static_cast(blob_count + num_potential_asc) < xheight_blob_count * total_fraction) { blob_count = 0; } int descdrop = blob_count > 0 ? -blob_index : 0; if (textord_debug_xheights) { tprintf("Descdrop: %d (potential ascenders %d, descenders %d)\n", descdrop, num_potential_asc, blob_count); heights.print(); } return descdrop; } /** * @name compute_height_modes * * Find the top maxmodes values in the input array and put their * indices in the output in the order in which they occurred. */ inT32 compute_height_modes(STATS *heights, // stats to search inT32 min_height, // bottom of range inT32 max_height, // top of range inT32 *modes, // output array inT32 maxmodes) { // size of modes inT32 pile_count; // no in source pile inT32 src_count; // no of source entries inT32 src_index; // current entry inT32 least_count; // height of smalllest inT32 least_index; // index of least inT32 dest_count; // index in modes src_count = max_height + 1 - min_height; dest_count = 0; least_count = MAX_INT32; least_index = -1; for (src_index = 0; src_index < src_count; src_index++) { pile_count = heights->pile_count(min_height + src_index); if (pile_count > 0) { if (dest_count < maxmodes) { if (pile_count < least_count) { // find smallest in array least_count = pile_count; least_index = dest_count; } modes[dest_count++] = min_height + src_index; } else if (pile_count >= least_count) { while (least_index < maxmodes - 1) { modes[least_index] = modes[least_index + 1]; // shuffle up least_index++; } // new one on end modes[maxmodes - 1] = min_height + src_index; if (pile_count == least_count) { // new smallest least_index = maxmodes - 1; } else { least_count = heights->pile_count(modes[0]); least_index = 0; for (dest_count = 1; dest_count < maxmodes; dest_count++) { pile_count = heights->pile_count(modes[dest_count]); if (pile_count < least_count) { // find smallest least_count = pile_count; least_index = dest_count; } } } } } } return dest_count; } /** * @name correct_row_xheight * * Adjust the xheight etc of this row if not within reasonable limits * of the average for the block. */ void correct_row_xheight(TO_ROW *row, float xheight, float ascrise, float descdrop) { ROW_CATEGORY row_category = get_row_category(row); if (textord_debug_xheights) { tprintf("correcting row xheight: row->xheight %.4f" ", row->acrise %.4f row->descdrop %.4f\n", row->xheight, row->ascrise, row->descdrop); } bool normal_xheight = within_error_margin(row->xheight, xheight, textord_xheight_error_margin); bool cap_xheight = within_error_margin(row->xheight, xheight + ascrise, textord_xheight_error_margin); // Use the average xheight/ascrise for the following cases: // -- the xheight of the row could not be determined at all // -- the row has descenders (e.g. "many groups", "ISBN 12345 p.3") // and its xheight is close to either cap height or average xheight // -- the row does not have ascenders or descenders, but its xheight // is close to the average block xheight (e.g. row with "www.mmm.com") if (row_category == ROW_ASCENDERS_FOUND) { if (row->descdrop >= 0.0) { row->descdrop = row->xheight * (descdrop / xheight); } } else if (row_category == ROW_INVALID || (row_category == ROW_DESCENDERS_FOUND && (normal_xheight || cap_xheight)) || (row_category == ROW_UNKNOWN && normal_xheight)) { if (textord_debug_xheights) tprintf("using average xheight\n"); row->xheight = xheight; row->ascrise = ascrise; row->descdrop = descdrop; } else if (row_category == ROW_DESCENDERS_FOUND) { // Assume this is a row with mostly lowercase letters and it's xheight // is computed correctly (unfortunately there is no way to distinguish // this from the case when descenders are found, but the most common // height is capheight). if (textord_debug_xheights) tprintf("lowercase, corrected ascrise\n"); row->ascrise = row->xheight * (ascrise / xheight); } else if (row_category == ROW_UNKNOWN) { // Otherwise assume this row is an all-caps or small-caps row // and adjust xheight and ascrise of the row. row->all_caps = true; if (cap_xheight) { // regular all caps if (textord_debug_xheights) tprintf("all caps\n"); row->xheight = xheight; row->ascrise = ascrise; row->descdrop = descdrop; } else { // small caps or caps with an odd xheight if (textord_debug_xheights) { if (row->xheight < xheight + ascrise && row->xheight > xheight) { tprintf("small caps\n"); } else { tprintf("all caps with irregular xheight\n"); } } row->ascrise = row->xheight * (ascrise / (xheight + ascrise)); row->xheight -= row->ascrise; row->descdrop = row->xheight * (descdrop / xheight); } } if (textord_debug_xheights) { tprintf("corrected row->xheight = %.4f, row->acrise = %.4f, row->descdrop" " = %.4f\n", row->xheight, row->ascrise, row->descdrop); } } static int CountOverlaps(const TBOX& box, int min_height, BLOBNBOX_LIST* blobs) { int overlaps = 0; BLOBNBOX_IT blob_it(blobs); for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) { BLOBNBOX* blob = blob_it.data(); const TBOX &blob_box = blob->bounding_box(); if (blob_box.height() >= min_height && box.major_overlap(blob_box)) { ++overlaps; } } return overlaps; } /** * @name separate_underlines * * Test wide objects for being potential underlines. If they are then * put them in a separate list in the block. */ void separate_underlines(TO_BLOCK *block, // block to do float gradient, // skew angle FCOORD rotation, // inverse landscape BOOL8 testing_on) { // correct orientation BLOBNBOX *blob; // current blob C_BLOB *rotated_blob; // rotated blob TO_ROW *row; // current row float length; // of g_vec TBOX blob_box; FCOORD blob_rotation; // inverse of rotation FCOORD g_vec; // skew rotation BLOBNBOX_IT blob_it; // iterator // iterator BLOBNBOX_IT under_it = &block->underlines; BLOBNBOX_IT large_it = &block->large_blobs; TO_ROW_IT row_it = block->get_rows(); int min_blob_height = static_cast(textord_min_blob_height_fraction * block->line_size + 0.5); // length of vector length = sqrt(1 + gradient * gradient); g_vec = FCOORD(1 / length, -gradient / length); blob_rotation = FCOORD(rotation.x(), -rotation.y()); blob_rotation.rotate(g_vec); // undoing everything for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) { row = row_it.data(); // get blobs blob_it.set_to_list(row->blob_list()); for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) { blob = blob_it.data(); blob_box = blob->bounding_box(); if (blob_box.width() > block->line_size * textord_underline_width) { ASSERT_HOST(blob->cblob() != NULL); rotated_blob = crotate_cblob (blob->cblob(), blob_rotation); if (test_underline( testing_on && textord_show_final_rows, rotated_blob, static_cast(row->intercept()), static_cast( block->line_size * (tesseract::CCStruct::kXHeightFraction + tesseract::CCStruct::kAscenderFraction / 2.0f)))) { under_it.add_after_then_move(blob_it.extract()); if (testing_on && textord_show_final_rows) { tprintf("Underlined blob at:"); rotated_blob->bounding_box().print(); tprintf("Was:"); blob_box.print(); } } else if (CountOverlaps(blob->bounding_box(), min_blob_height, row->blob_list()) > textord_max_blob_overlaps) { large_it.add_after_then_move(blob_it.extract()); if (testing_on && textord_show_final_rows) { tprintf("Large blob overlaps %d blobs at:", CountOverlaps(blob_box, min_blob_height, row->blob_list())); blob_box.print(); } } delete rotated_blob; } } } } /** * @name pre_associate_blobs * * Associate overlapping blobs and fake chop wide blobs. */ void pre_associate_blobs( //make rough chars ICOORD page_tr, //top right TO_BLOCK *block, //block to do FCOORD rotation, //inverse landscape BOOL8 testing_on //correct orientation ) { #ifndef GRAPHICS_DISABLED ScrollView::Color colour; //of boxes #endif BLOBNBOX *blob; //current blob BLOBNBOX *nextblob; //next in list TBOX blob_box; FCOORD blob_rotation; //inverse of rotation BLOBNBOX_IT blob_it; //iterator BLOBNBOX_IT start_it; //iterator TO_ROW_IT row_it = block->get_rows (); #ifndef GRAPHICS_DISABLED colour = ScrollView::RED; #endif blob_rotation = FCOORD (rotation.x (), -rotation.y ()); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { //get blobs blob_it.set_to_list (row_it.data ()->blob_list ()); for (blob_it.mark_cycle_pt (); !blob_it.cycled_list (); blob_it.forward ()) { blob = blob_it.data (); blob_box = blob->bounding_box (); start_it = blob_it; //save start point // if (testing_on && textord_show_final_blobs) // { // tprintf("Blob at (%d,%d)->(%d,%d), addr=%x, count=%d\n", // blob_box.left(),blob_box.bottom(), // blob_box.right(),blob_box.top(), // (void*)blob,blob_it.length()); // } bool overlap; do { overlap = false; if (!blob_it.at_last ()) { nextblob = blob_it.data_relative(1); overlap = blob_box.major_x_overlap(nextblob->bounding_box()); if (overlap) { blob->merge(nextblob); // merge new blob blob_box = blob->bounding_box(); // get bigger box blob_it.forward(); } } } while (overlap); blob->chop (&start_it, &blob_it, blob_rotation, block->line_size * tesseract::CCStruct::kXHeightFraction * textord_chop_width); //attempt chop } #ifndef GRAPHICS_DISABLED if (testing_on && textord_show_final_blobs) { if (to_win == NULL) create_to_win(page_tr); to_win->Pen(colour); for (blob_it.mark_cycle_pt (); !blob_it.cycled_list (); blob_it.forward ()) { blob = blob_it.data (); blob_box = blob->bounding_box (); blob_box.rotate (rotation); if (!blob->joined_to_prev ()) { to_win->Rectangle (blob_box.left (), blob_box.bottom (), blob_box.right (), blob_box.top ()); } } colour = (ScrollView::Color) (colour + 1); if (colour > ScrollView::MAGENTA) colour = ScrollView::RED; } #endif } } /** * @name fit_parallel_rows * * Re-fit the rows in the block to the given gradient. */ void fit_parallel_rows( //find lines TO_BLOCK *block, //block to do float gradient, //gradient to fit FCOORD rotation, //for drawing inT32 block_edge, //edge of block BOOL8 testing_on //correct orientation ) { #ifndef GRAPHICS_DISABLED ScrollView::Color colour; //of row #endif TO_ROW_IT row_it = block->get_rows (); row_it.move_to_first (); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { if (row_it.data ()->blob_list ()->empty ()) delete row_it.extract (); //nothing in it else fit_parallel_lms (gradient, row_it.data ()); } #ifndef GRAPHICS_DISABLED if (testing_on) { colour = ScrollView::RED; for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { plot_parallel_row (row_it.data (), gradient, block_edge, colour, rotation); colour = (ScrollView::Color) (colour + 1); if (colour > ScrollView::MAGENTA) colour = ScrollView::RED; } } #endif row_it.sort (row_y_order); //may have gone out of order } /** * @name fit_parallel_lms * * Fit an LMS line to a row. * Make the fit parallel to the given gradient and set the * row accordingly. */ void fit_parallel_lms(float gradient, TO_ROW *row) { float c; // fitted line int blobcount; // no of blobs tesseract::DetLineFit lms; BLOBNBOX_IT blob_it = row->blob_list(); blobcount = 0; for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) { if (!blob_it.data()->joined_to_prev()) { const TBOX& box = blob_it.data()->bounding_box(); lms.Add(ICOORD((box.left() + box.right()) / 2, box.bottom())); blobcount++; } } double error = lms.ConstrainedFit(gradient, &c); row->set_parallel_line(gradient, c, error); if (textord_straight_baselines && blobcount > textord_lms_line_trials) { error = lms.Fit(&gradient, &c); } //set the other too row->set_line(gradient, c, error); } /** * @name make_spline_rows * * Re-fit the rows in the block to the given gradient. */ namespace tesseract { void Textord::make_spline_rows(TO_BLOCK *block, // block to do float gradient, // gradient to fit BOOL8 testing_on) { #ifndef GRAPHICS_DISABLED ScrollView::Color colour; //of row #endif TO_ROW_IT row_it = block->get_rows (); row_it.move_to_first (); for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { if (row_it.data ()->blob_list ()->empty ()) delete row_it.extract (); //nothing in it else make_baseline_spline (row_it.data (), block); } if (textord_old_baselines) { #ifndef GRAPHICS_DISABLED if (testing_on) { colour = ScrollView::RED; for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { row_it.data ()->baseline.plot (to_win, colour); colour = (ScrollView::Color) (colour + 1); if (colour > ScrollView::MAGENTA) colour = ScrollView::RED; } } #endif make_old_baselines(block, testing_on, gradient); } #ifndef GRAPHICS_DISABLED if (testing_on) { colour = ScrollView::RED; for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ()) { row_it.data ()->baseline.plot (to_win, colour); colour = (ScrollView::Color) (colour + 1); if (colour > ScrollView::MAGENTA) colour = ScrollView::RED; } } #endif } } // namespace tesseract. /** * @name make_baseline_spline * * Fit an LMS line to a row. * Make the fit parallel to the given gradient and set the * row accordingly. */ void make_baseline_spline(TO_ROW *row, //row to fit TO_BLOCK *block) { inT32 *xstarts; // spline boundaries double *coeffs; // quadratic coeffs inT32 segments; // no of segments xstarts = (inT32 *) alloc_mem((row->blob_list()->length() + 1) * sizeof(inT32)); if (segment_baseline(row, block, segments, xstarts) && !textord_straight_baselines && !textord_parallel_baselines) { coeffs = linear_spline_baseline(row, block, segments, xstarts); } else { xstarts[1] = xstarts[segments]; segments = 1; coeffs = (double *) alloc_mem (3 * sizeof (double)); coeffs[0] = 0; coeffs[1] = row->line_m (); coeffs[2] = row->line_c (); } row->baseline = QSPLINE (segments, xstarts, coeffs); free_mem(coeffs); free_mem(xstarts); } /** * @name segment_baseline * * Divide the baseline up into segments which require a different * quadratic fitted to them. * Return TRUE if enough blobs were far enough away to need a quadratic. */ BOOL8 segment_baseline ( //split baseline TO_ROW * row, //row to fit TO_BLOCK * block, //block it came from inT32 & segments, //no fo segments inT32 xstarts[] //coords of segments ) { BOOL8 needs_curve; //needs curved line int blobcount; //no of blobs int blobindex; //current blob int last_state; //above, on , below int state; //of current blob float yshift; //from baseline TBOX box; //blob box TBOX new_box; //new_it box float middle; //xcentre of blob //blobs BLOBNBOX_IT blob_it = row->blob_list (); BLOBNBOX_IT new_it = blob_it; //front end SORTED_FLOATS yshifts; //shifts from baseline needs_curve = FALSE; box = box_next_pre_chopped (&blob_it); xstarts[0] = box.left (); segments = 1; blobcount = row->blob_list ()->length (); if (textord_oldbl_debug) tprintf ("Segmenting baseline of %d blobs at (%d,%d)\n", blobcount, box.left (), box.bottom ()); if (blobcount <= textord_spline_medianwin || blobcount < textord_spline_minblobs) { blob_it.move_to_last (); box = blob_it.data ()->bounding_box (); xstarts[1] = box.right (); return FALSE; } last_state = 0; new_it.mark_cycle_pt (); for (blobindex = 0; blobindex < textord_spline_medianwin; blobindex++) { new_box = box_next_pre_chopped (&new_it); middle = (new_box.left () + new_box.right ()) / 2.0; yshift = new_box.bottom () - row->line_m () * middle - row->line_c (); //record shift yshifts.add (yshift, blobindex); if (new_it.cycled_list ()) { xstarts[1] = new_box.right (); return FALSE; } } for (blobcount = 0; blobcount < textord_spline_medianwin / 2; blobcount++) box = box_next_pre_chopped (&blob_it); do { new_box = box_next_pre_chopped (&new_it); //get middle one yshift = yshifts[textord_spline_medianwin / 2]; if (yshift > textord_spline_shift_fraction * block->line_size) state = 1; else if (-yshift > textord_spline_shift_fraction * block->line_size) state = -1; else state = 0; if (state != 0) needs_curve = TRUE; // tprintf("State=%d, prev=%d, shift=%g\n", // state,last_state,yshift); if (state != last_state && blobcount > textord_spline_minblobs) { xstarts[segments++] = box.left (); blobcount = 0; } last_state = state; yshifts.remove (blobindex - textord_spline_medianwin); box = box_next_pre_chopped (&blob_it); middle = (new_box.left () + new_box.right ()) / 2.0; yshift = new_box.bottom () - row->line_m () * middle - row->line_c (); yshifts.add (yshift, blobindex); blobindex++; blobcount++; } while (!new_it.cycled_list ()); if (blobcount > textord_spline_minblobs || segments == 1) { xstarts[segments] = new_box.right (); } else { xstarts[--segments] = new_box.right (); } if (textord_oldbl_debug) tprintf ("Made %d segments on row at (%d,%d)\n", segments, box.right (), box.bottom ()); return needs_curve; } /** * @name linear_spline_baseline * * Divide the baseline up into segments which require a different * quadratic fitted to them. * @return TRUE if enough blobs were far enough away to need a quadratic. */ double * linear_spline_baseline ( //split baseline TO_ROW * row, //row to fit TO_BLOCK * block, //block it came from inT32 & segments, //no fo segments inT32 xstarts[] //coords of segments ) { int blobcount; //no of blobs int blobindex; //current blob int index1, index2; //blob numbers int blobs_per_segment; //blobs in each TBOX box; //blob box TBOX new_box; //new_it box //blobs BLOBNBOX_IT blob_it = row->blob_list (); BLOBNBOX_IT new_it = blob_it; //front end float b, c; //fitted curve tesseract::DetLineFit lms; double *coeffs; //quadratic coeffs inT32 segment; //current segment box = box_next_pre_chopped (&blob_it); xstarts[0] = box.left (); blobcount = 1; while (!blob_it.at_first ()) { blobcount++; box = box_next_pre_chopped (&blob_it); } segments = blobcount / textord_spline_medianwin; if (segments < 1) segments = 1; blobs_per_segment = blobcount / segments; coeffs = (double *) alloc_mem (segments * 3 * sizeof (double)); if (textord_oldbl_debug) tprintf ("Linear splining baseline of %d blobs at (%d,%d), into %d segments of %d blobs\n", blobcount, box.left (), box.bottom (), segments, blobs_per_segment); segment = 1; for (index2 = 0; index2 < blobs_per_segment / 2; index2++) box_next_pre_chopped(&new_it); index1 = 0; blobindex = index2; do { blobindex += blobs_per_segment; lms.Clear(); while (index1 < blobindex || (segment == segments && index1 < blobcount)) { box = box_next_pre_chopped (&blob_it); int middle = (box.left() + box.right()) / 2; lms.Add(ICOORD(middle, box.bottom())); index1++; if (index1 == blobindex - blobs_per_segment / 2 || index1 == blobcount - 1) { xstarts[segment] = box.left (); } } lms.Fit(&b, &c); coeffs[segment * 3 - 3] = 0; coeffs[segment * 3 - 2] = b; coeffs[segment * 3 - 1] = c; segment++; if (segment > segments) break; blobindex += blobs_per_segment; lms.Clear(); while (index2 < blobindex || (segment == segments && index2 < blobcount)) { new_box = box_next_pre_chopped (&new_it); int middle = (new_box.left() + new_box.right()) / 2; lms.Add(ICOORD (middle, new_box.bottom())); index2++; if (index2 == blobindex - blobs_per_segment / 2 || index2 == blobcount - 1) { xstarts[segment] = new_box.left (); } } lms.Fit(&b, &c); coeffs[segment * 3 - 3] = 0; coeffs[segment * 3 - 2] = b; coeffs[segment * 3 - 1] = c; segment++; } while (segment <= segments); return coeffs; } /** * @name assign_blobs_to_rows * * Make enough rows to allocate all the given blobs to one. * If a block skew is given, use that, else attempt to track it. */ void assign_blobs_to_rows( //find lines TO_BLOCK *block, //block to do float *gradient, //block skew int pass, //identification BOOL8 reject_misses, //chuck big ones out BOOL8 make_new_rows, //add rows for unmatched BOOL8 drawing_skew //draw smoothed skew ) { OVERLAP_STATE overlap_result; //what to do with it float ycoord; //current y float top, bottom; //of blob float g_length = 1.0f; //from gradient inT16 row_count; //no of rows inT16 left_x; //left edge inT16 last_x; //previous edge float block_skew; //y delta float smooth_factor; //for new coords float near_dist; //dist to nearest row ICOORD testpt; //testing only BLOBNBOX *blob; //current blob TO_ROW *row; //current row TO_ROW *dest_row = NULL; //row to put blob in //iterators BLOBNBOX_IT blob_it = &block->blobs; TO_ROW_IT row_it = block->get_rows (); ycoord = (block->block->bounding_box ().bottom () + block->block->bounding_box ().top ()) / 2.0f; if (gradient != NULL) g_length = sqrt (1 + *gradient * *gradient); #ifndef GRAPHICS_DISABLED if (drawing_skew) to_win->SetCursor(block->block->bounding_box ().left (), ycoord); #endif testpt = ICOORD (textord_test_x, textord_test_y); blob_it.sort (blob_x_order); smooth_factor = 1.0; block_skew = 0.0f; row_count = row_it.length (); //might have rows if (!blob_it.empty ()) { left_x = blob_it.data ()->bounding_box ().left (); } else { left_x = block->block->bounding_box ().left (); } last_x = left_x; for (blob_it.mark_cycle_pt (); !blob_it.cycled_list (); blob_it.forward ()) { blob = blob_it.data (); if (gradient != NULL) { block_skew = (1 - 1 / g_length) * blob->bounding_box ().bottom () + *gradient / g_length * blob->bounding_box ().left (); } else if (blob->bounding_box ().left () - last_x > block->line_size / 2 && last_x - left_x > block->line_size * 2 && textord_interpolating_skew) { // tprintf("Interpolating skew from %g",block_skew); block_skew *= (float) (blob->bounding_box ().left () - left_x) / (last_x - left_x); // tprintf("to %g\n",block_skew); } last_x = blob->bounding_box ().left (); top = blob->bounding_box ().top () - block_skew; bottom = blob->bounding_box ().bottom () - block_skew; #ifndef GRAPHICS_DISABLED if (drawing_skew) to_win->DrawTo(blob->bounding_box ().left (), ycoord + block_skew); #endif if (!row_it.empty ()) { for (row_it.move_to_first (); !row_it.at_last () && row_it.data ()->min_y () > top; row_it.forward ()); row = row_it.data (); if (row->min_y () <= top && row->max_y () >= bottom) { //any overlap dest_row = row; overlap_result = most_overlapping_row (&row_it, dest_row, top, bottom, block->line_size, blob->bounding_box (). contains (testpt)); if (overlap_result == NEW_ROW && !reject_misses) overlap_result = ASSIGN; } else { overlap_result = NEW_ROW; if (!make_new_rows) { near_dist = row_it.data_relative (-1)->min_y () - top; //below bottom if (bottom < row->min_y ()) { if (row->min_y () - bottom <= (block->line_spacing - block->line_size) * tesseract::CCStruct::kDescenderFraction) { //done it overlap_result = ASSIGN; dest_row = row; } } else if (near_dist > 0 && near_dist < bottom - row->max_y ()) { row_it.backward (); dest_row = row_it.data (); if (dest_row->min_y () - bottom <= (block->line_spacing - block->line_size) * tesseract::CCStruct::kDescenderFraction) { //done it overlap_result = ASSIGN; } } else { if (top - row->max_y () <= (block->line_spacing - block->line_size) * (textord_overlap_x + tesseract::CCStruct::kAscenderFraction)) { //done it overlap_result = ASSIGN; dest_row = row; } } } } if (overlap_result == ASSIGN) dest_row->add_blob (blob_it.extract (), top, bottom, block->line_size); if (overlap_result == NEW_ROW) { if (make_new_rows && top - bottom < block->max_blob_size) { dest_row = new TO_ROW (blob_it.extract (), top, bottom, block->line_size); row_count++; if (bottom > row_it.data ()->min_y ()) row_it.add_before_then_move (dest_row); //insert in right place else row_it.add_after_then_move (dest_row); smooth_factor = 1.0 / (row_count * textord_skew_lag + textord_skewsmooth_offset); } else overlap_result = REJECT; } } else if (make_new_rows && top - bottom < block->max_blob_size) { overlap_result = NEW_ROW; dest_row = new TO_ROW(blob_it.extract(), top, bottom, block->line_size); row_count++; row_it.add_after_then_move(dest_row); smooth_factor = 1.0 / (row_count * textord_skew_lag + textord_skewsmooth_offset2); } else overlap_result = REJECT; if (blob->bounding_box ().contains(testpt) && textord_debug_blob) { if (overlap_result != REJECT) { tprintf("Test blob assigned to row at (%g,%g) on pass %d\n", dest_row->min_y(), dest_row->max_y(), pass); } else { tprintf("Test blob assigned to no row on pass %d\n", pass); } } if (overlap_result != REJECT) { while (!row_it.at_first() && row_it.data()->min_y() > row_it.data_relative(-1)->min_y()) { row = row_it.extract(); row_it.backward(); row_it.add_before_then_move(row); } while (!row_it.at_last() && row_it.data ()->min_y() < row_it.data_relative (1)->min_y()) { row = row_it.extract(); row_it.forward(); // Keep rows in order. row_it.add_after_then_move(row); } BLOBNBOX_IT added_blob_it(dest_row->blob_list()); added_blob_it.move_to_last(); TBOX prev_box = added_blob_it.data_relative(-1)->bounding_box(); if (dest_row->blob_list()->singleton() || !prev_box.major_x_overlap(blob->bounding_box())) { block_skew = (1 - smooth_factor) * block_skew + smooth_factor * (blob->bounding_box().bottom() - dest_row->initial_min_y()); } } } for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) { if (row_it.data()->blob_list()->empty()) delete row_it.extract(); // Discard empty rows. } } /** * @name most_overlapping_row * * Return the row which most overlaps the blob. */ OVERLAP_STATE most_overlapping_row( //find best row TO_ROW_IT *row_it, //iterator TO_ROW *&best_row, //output row float top, //top of blob float bottom, //bottom of blob float rowsize, //max row size BOOL8 testing_blob //test stuff ) { OVERLAP_STATE result; //result of tests float overlap; //of blob & row float bestover; //nearest row float merge_top, merge_bottom; //size of merged row ICOORD testpt; //testing only TO_ROW *row; //current row TO_ROW *test_row; //for multiple overlaps BLOBNBOX_IT blob_it; //for merging rows result = ASSIGN; row = row_it->data (); bestover = top - bottom; if (top > row->max_y ()) bestover -= top - row->max_y (); if (bottom < row->min_y ()) //compute overlap bestover -= row->min_y () - bottom; if (testing_blob && textord_debug_blob) { tprintf("Test blob y=(%g,%g), row=(%f,%f), size=%g, overlap=%f\n", bottom, top, row->min_y(), row->max_y(), rowsize, bestover); } test_row = row; do { if (!row_it->at_last ()) { row_it->forward (); test_row = row_it->data (); if (test_row->min_y () <= top && test_row->max_y () >= bottom) { merge_top = test_row->max_y () > row->max_y ()? test_row->max_y () : row->max_y (); merge_bottom = test_row->min_y () < row->min_y ()? test_row->min_y () : row->min_y (); if (merge_top - merge_bottom <= rowsize) { if (testing_blob) { tprintf ("Merging rows at (%g,%g), (%g,%g)\n", row->min_y (), row->max_y (), test_row->min_y (), test_row->max_y ()); } test_row->set_limits (merge_bottom, merge_top); blob_it.set_to_list (test_row->blob_list ()); blob_it.add_list_after (row->blob_list ()); blob_it.sort (blob_x_order); row_it->backward (); delete row_it->extract (); row_it->forward (); bestover = -1.0f; //force replacement } overlap = top - bottom; if (top > test_row->max_y ()) overlap -= top - test_row->max_y (); if (bottom < test_row->min_y ()) overlap -= test_row->min_y () - bottom; if (bestover >= rowsize - 1 && overlap >= rowsize - 1) { result = REJECT; } if (overlap > bestover) { bestover = overlap; //find biggest overlap row = test_row; } if (testing_blob && textord_debug_blob) { tprintf("Test blob y=(%g,%g), row=(%f,%f), size=%g, overlap=%f->%f\n", bottom, top, test_row->min_y(), test_row->max_y(), rowsize, overlap, bestover); } } } } while (!row_it->at_last () && test_row->min_y () <= top && test_row->max_y () >= bottom); while (row_it->data () != row) row_it->backward (); //make it point to row //doesn't overlap much if (top - bottom - bestover > rowsize * textord_overlap_x && (!textord_fix_makerow_bug || bestover < rowsize * textord_overlap_x) && result == ASSIGN) result = NEW_ROW; //doesn't overlap enough best_row = row; return result; } /** * @name blob_x_order * * Sort function to sort blobs in x from page left. */ int blob_x_order( //sort function const void *item1, //items to compare const void *item2) { //converted ptr BLOBNBOX *blob1 = *(BLOBNBOX **) item1; //converted ptr BLOBNBOX *blob2 = *(BLOBNBOX **) item2; if (blob1->bounding_box ().left () < blob2->bounding_box ().left ()) return -1; else if (blob1->bounding_box ().left () > blob2->bounding_box ().left ()) return 1; else return 0; } /** * @name row_y_order * * Sort function to sort rows in y from page top. */ int row_y_order( //sort function const void *item1, //items to compare const void *item2) { //converted ptr TO_ROW *row1 = *(TO_ROW **) item1; //converted ptr TO_ROW *row2 = *(TO_ROW **) item2; if (row1->parallel_c () > row2->parallel_c ()) return -1; else if (row1->parallel_c () < row2->parallel_c ()) return 1; else return 0; } /** * @name row_spacing_order * * Qsort style function to compare 2 TO_ROWS based on their spacing value. */ int row_spacing_order( //sort function const void *item1, //items to compare const void *item2) { //converted ptr TO_ROW *row1 = *(TO_ROW **) item1; //converted ptr TO_ROW *row2 = *(TO_ROW **) item2; if (row1->spacing < row2->spacing) return -1; else if (row1->spacing > row2->spacing) return 1; else return 0; } /** * @name mark_repeated_chars * * Mark blobs marked with BTFT_LEADER in repeated sets using the * repeated_set member of BLOBNBOX. */ void mark_repeated_chars(TO_ROW *row) { BLOBNBOX_IT box_it(row->blob_list()); // Iterator. int num_repeated_sets = 0; if (!box_it.empty()) { do { BLOBNBOX* bblob = box_it.data(); int repeat_length = 1; if (bblob->flow() == BTFT_LEADER && !bblob->joined_to_prev() && bblob->cblob() != NULL) { BLOBNBOX_IT test_it(box_it); for (test_it.forward(); !test_it.at_first();) { bblob = test_it.data(); if (bblob->flow() != BTFT_LEADER) break; test_it.forward(); bblob = test_it.data(); if (bblob->joined_to_prev() || bblob->cblob() == NULL) { repeat_length = 0; break; } ++repeat_length; } } if (repeat_length >= kMinLeaderCount) { num_repeated_sets++; for (; repeat_length > 0; box_it.forward(), --repeat_length) { bblob = box_it.data(); bblob->set_repeated_set(num_repeated_sets); } } else { bblob->set_repeated_set(0); box_it.forward(); } } while (!box_it.at_first()); // until all done } row->set_num_repeated_sets(num_repeated_sets); }