makerow.cpp

来自「一个google的OCR源码」· C++ 代码 · 共 1,682 行 · 第 1/5 页

// 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;
}

static 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.
        if (blob->blob() != NULL)
          delete blob->blob();
        if (blob->cblob() != NULL)
          delete blob->cblob();
        delete b_it.extract();
      } else {
        prev = blob;
      }
    }
  }
}

/**********************************************************************
 * cleanup_rows
 *
 * Remove overlapping rows and fit all the blobs to what's left.
 **********************************************************************/

void cleanup_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
                 ) {
                                 //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);
  //no rows for noise
  row_it.set_to_list (block->get_rows ());
  for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ())
    row_it.data ()->blob_list ()->sort (blob_x_order);
  fit_parallel_rows(block, gradient, rotation, block_edge, FALSE);
  if (textord_heavy_nr) {
    vigorous_noise_removal(block);
  }
  separate_underlines(block, gradient, rotation, testing_on);
  pre_associate_blobs(page_tr, block, rotation, testing_on);

#ifndef GRAPHICS_DISABLED
  if (textord_show_final_rows && testing_on) {
    if (to_win == NULL)
      create_to_win(page_tr);
  }
#endif

  fit_parallel_rows(block, gradient, rotation, block_edge, FALSE);
  //              textord_show_final_rows && testing_on);
  make_spline_rows(block,
                   gradient,
                   rotation,
                   block_edge,
                   textord_show_final_rows &&testing_on);
  if (!textord_old_xheight || !textord_old_baselines)
    compute_block_xheight(block, gradient);
  if (textord_restore_underlines)
                                 //fix underlines
    restore_underlined_blobs(block);
#ifndef GRAPHICS_DISABLED
  if (textord_show_final_rows && testing_on) {
    plot_blob_list (to_win, &block->blobs,
                    ScrollView::MAGENTA, ScrollView::WHITE);
    //show discarded blobs
    plot_blob_list (to_win, &block->underlines,
                    ScrollView::YELLOW, ScrollView::CORAL);
  }
  if (textord_show_final_rows && testing_on && block->blobs.length () > 0)
    tprintf ("%d blobs discarded as noise\n", block->blobs.length ());
  if (textord_show_final_rows && testing_on) {
    draw_meanlines(block, gradient, block_edge, ScrollView::WHITE, rotation);
  }
#endif
}


/**********************************************************************
 * 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 *
    (textord_merge_desc +
    textord_merge_asc)),
    (inT32) ceil (block->line_spacing *
    (textord_merge_x +
    textord_merge_asc)),
    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);
}


/**********************************************************************
 * 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 neigbouring row