makerow.cpp

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

  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;
}


/**********************************************************************
 * 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;
}


/**********************************************************************
 * 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
  float top, bottom;             //coords of blob
  inT32 width;                   //of blob
  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
      top = blob_box.top ();
      bottom = blob_box.bottom ();
      width =
        (inT32) floor ((FLOAT32) (blob_box.right () - blob_box.left ()));
      if ((inT32) floor (bottom) < min_y
        || (inT32) floor (bottom) - min_y >= line_count)
        fprintf (stderr,
          "Bad y coord of bottom, " INT32FORMAT "(" INT32FORMAT ","
          INT32FORMAT ")\n", (inT32) floor (bottom), min_y, max_y);
                                 //count transitions
      index = (inT32) floor (bottom) - min_y;
      deltas[index] += width;
      if ((inT32) floor (top) < min_y
        || (inT32) floor (top) - min_y >= line_count)
        fprintf (stderr,
          "Bad y coord of top, " INT32FORMAT "(" INT32FORMAT ","
          INT32FORMAT ")\n", (inT32) floor (top), min_y, max_y);
      index = (inT32) floor (top) - min_y;
      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
}


/**********************************************************************
 * 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);
}


/**********************************************************************
 * 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);