DMZ_INTERNAL void gather_character_rects(GroupedRects &group, const GroupedRects &sub_group) {
group.sum += sub_group.sum;
if (sub_group.character_rects.size() == 0) {
group.character_rects.push_back(CharacterRect(sub_group.top, sub_group.left, sub_group.sum));
}
else {
group.character_rects.insert(group.character_rects.end(), sub_group.character_rects.begin(), sub_group.character_rects.end());
}
}
// FOR CYTHON USE ONLY
GroupedRects cythonGroupedRects_to_GroupedRects(CythonGroupedRects *cython_group) {
GroupedRects group;
group.top = cython_group->top;
group.left = cython_group->left;
group.width = cython_group->width;
group.height = cython_group->height;
group.character_width = cython_group->character_width;
group.pattern = (ExpiryPattern) cython_group->pattern;
group.scores = cythonScores_to_ExpiryGroupScores(cython_group->scores);
group.recently_seen_count = cython_group->recently_seen_count;
group.total_seen_count = cython_group->total_seen_count;
for (int character_index = 0; character_index < cython_group->number_of_character_rects; character_index++) {
CythonCharacterRect cython_rect = cython_group->character_rects[character_index];
CharacterRect rect = CharacterRect(cython_rect.top, cython_rect.left, 0);
group.character_rects.push_back(rect);
}
return group;
}
DMZ_INTERNAL void regrid_group(IplImage *sobel_image, GroupedRects &group) {
// Choose grid-spacing (and starting column) to minimize the sum of pixel-values covered by the grid lines,
// while maximizing the sum of pixel-values within the grid squares.
// I.e., minimize the ratio of the former to the latter.
#define MIN_GRID_SPACING 11
#define MAX_GRID_SPACING 15
int best_grid_spacing = 0;
int best_starting_col_offset = 0;
float best_ratio = MAXFLOAT;
int bounds_left = MAX(group.left - 2 * kSmallCharacterWidth, 0);
int bounds_right = MIN(group.left + group.width + 2 * kSmallCharacterWidth, kCreditCardTargetWidth);
int bounds_width = bounds_right - bounds_left;
int minimum_allowable_number_of_grid_lines = (int)(floorf(float(bounds_width) / float(MIN_GRID_SPACING)));
long group_sum = 0;
long col_sums[bounds_width];
for (int col = bounds_left; col < bounds_right; col++) {
long col_sum = 0;
for (int row = group.top; row < group.top + group.height; row++) {
col_sum += CV_IMAGE_ELEM(sobel_image, short, row, col);
}
col_sums[col - bounds_left] = col_sum;
group_sum += col_sum;
}
for (int grid_spacing = MIN_GRID_SPACING; grid_spacing <= MAX_GRID_SPACING; grid_spacing++) {
for (int starting_col_offset = 0; starting_col_offset < grid_spacing; starting_col_offset++) {
float grid_line_sum = 0.0;
int number_of_grid_lines = 0;
int grid_line_offset = starting_col_offset;
while (grid_line_offset < bounds_width) {
number_of_grid_lines += 1;
grid_line_sum += col_sums[grid_line_offset];
grid_line_offset += grid_spacing;
}
float average_grid_line_sum = grid_line_sum / float(number_of_grid_lines);
grid_line_sum = average_grid_line_sum * minimum_allowable_number_of_grid_lines;
float ratio = grid_line_sum / (group_sum - grid_line_sum);
if (ratio < best_ratio) {
best_ratio = ratio;
best_grid_spacing = grid_spacing;
best_starting_col_offset = starting_col_offset;
}
}
}
CharacterRectList regridded_rects;
int grid_line_offset = best_starting_col_offset;
while (grid_line_offset + 1 < bounds_width) {
long sum = 0;
for (int col = grid_line_offset + 1; col < MIN(grid_line_offset + best_grid_spacing, bounds_width); col++) {
sum += col_sums[col];
}
regridded_rects.push_back(CharacterRect(group.top, bounds_left + grid_line_offset + 1, sum));
grid_line_offset += best_grid_spacing;
}
group.character_rects = regridded_rects;
group.character_width = best_grid_spacing - 1;
group.left = group.character_rects[0].left;
group.width = (group.character_rects.end() - 1)->left + group.character_width - group.left;
strip_group_white_space(group);
}