tesseract
3.03
|
#include <associate.h>
Static Public Member Functions | |
static float | ComputeOutlineLength (float rating_cert_scale, const BLOB_CHOICE &b) |
static float | ComputeRating (float rating_cert_scale, float cert, int width) |
static void | ComputeStats (int col, int row, const AssociateStats *parent_stats, int parent_path_length, bool fixed_pitch, float max_char_wh_ratio, WERD_RES *word_res, bool debug, AssociateStats *stats) |
static float | FixedPitchWidthCost (float norm_width, float right_gap, bool end_pos, float max_char_wh_ratio) |
static float | FixedPitchGapCost (float norm_gap, bool end_pos) |
Static Public Attributes | |
static const float | kMaxFixedPitchCharAspectRatio = 2.0f |
static const float | kMinGap = 0.03f |
Definition at line 69 of file associate.h.
static float tesseract::AssociateUtils::ComputeOutlineLength | ( | float | rating_cert_scale, |
const BLOB_CHOICE & | b | ||
) | [inline, static] |
Definition at line 82 of file associate.h.
static float tesseract::AssociateUtils::ComputeRating | ( | float | rating_cert_scale, |
float | cert, | ||
int | width | ||
) | [inline, static] |
Definition at line 86 of file associate.h.
{ return static_cast<float>(width) * cert / rating_cert_scale; }
void tesseract::AssociateUtils::ComputeStats | ( | int | col, |
int | row, | ||
const AssociateStats * | parent_stats, | ||
int | parent_path_length, | ||
bool | fixed_pitch, | ||
float | max_char_wh_ratio, | ||
WERD_RES * | word_res, | ||
bool | debug, | ||
AssociateStats * | stats | ||
) | [static] |
Definition at line 37 of file associate.cpp.
{ stats->Clear(); ASSERT_HOST(word_res != NULL); if (word_res->blob_widths.empty()) { return; } if (debug) { tprintf("AssociateUtils::ComputeStats() for col=%d, row=%d%s\n", col, row, fixed_pitch ? " (fixed pitch)" : ""); } float normalizing_height = kBlnXHeight; ROW* blob_row = word_res->blob_row; // TODO(rays/daria) Can unicharset.script_has_xheight be useful here? if (fixed_pitch && blob_row != NULL) { // For fixed pitch language like CJK, we use the full text height // as the normalizing factor so we are not dependent on xheight // calculation. if (blob_row->body_size() > 0.0f) { normalizing_height = word_res->denorm.y_scale() * blob_row->body_size(); } else { normalizing_height = word_res->denorm.y_scale() * (blob_row->x_height() + blob_row->ascenders()); } if (debug) { tprintf("normalizing height = %g (scale %g xheight %g ascenders %g)\n", normalizing_height, word_res->denorm.y_scale(), blob_row->x_height(), blob_row->ascenders()); } } float wh_ratio = word_res->GetBlobsWidth(col, row) / normalizing_height; if (wh_ratio > max_char_wh_ratio) stats->bad_shape = true; // Compute the gap sum for this shape. If there are only negative or only // positive gaps, record their sum in stats->gap_sum. However, if there is // a mixture, record only the sum of the positive gaps. // TODO(antonova): explain fragment. int negative_gap_sum = 0; for (int c = col; c < row; ++c) { int gap = word_res->GetBlobsGap(c); (gap > 0) ? stats->gap_sum += gap : negative_gap_sum += gap; } if (stats->gap_sum == 0) stats->gap_sum = negative_gap_sum; if (debug) { tprintf("wh_ratio=%g (max_char_wh_ratio=%g) gap_sum=%d %s\n", wh_ratio, max_char_wh_ratio, stats->gap_sum, stats->bad_shape ? "bad_shape" : ""); } // Compute shape_cost (for fixed pitch mode). if (fixed_pitch) { bool end_row = (row == (word_res->ratings->dimension() - 1)); // Ensure that the blob has gaps on the left and the right sides // (except for beginning and ending punctuation) and that there is // no cutting through ink at the blob boundaries. if (col > 0) { float left_gap = word_res->GetBlobsGap(col - 1) / normalizing_height; SEAM *left_seam = word_res->seam_array[col - 1]; if ((!end_row && left_gap < kMinGap) || left_seam->priority > 0.0f) { stats->bad_shape = true; } if (debug) { tprintf("left_gap %g, left_seam %g %s\n", left_gap, left_seam->priority, stats->bad_shape ? "bad_shape" : ""); } } float right_gap = 0.0f; if (!end_row) { right_gap = word_res->GetBlobsGap(row) / normalizing_height; SEAM *right_seam = word_res->seam_array[row]; if (right_gap < kMinGap || right_seam->priority > 0.0f) { stats->bad_shape = true; if (right_gap < kMinGap) stats->bad_fixed_pitch_right_gap = true; } if (debug) { tprintf("right_gap %g right_seam %g %s\n", right_gap, right_seam->priority, stats->bad_shape ? "bad_shape" : ""); } } // Impose additional segmentation penalties if blob widths or gaps // distribution don't fit a fixed-pitch model. // Since we only know the widths and gaps of the path explored so far, // the means and variances are computed for the path so far (not // considering characters to the right of the last character on the path). stats->full_wh_ratio = wh_ratio + right_gap; if (parent_stats != NULL) { stats->full_wh_ratio_total = (parent_stats->full_wh_ratio_total + stats->full_wh_ratio); float mean = stats->full_wh_ratio_total / static_cast<float>(parent_path_length+1); stats->full_wh_ratio_var = parent_stats->full_wh_ratio_var + pow(mean-stats->full_wh_ratio, 2); } else { stats->full_wh_ratio_total = stats->full_wh_ratio; } if (debug) { tprintf("full_wh_ratio %g full_wh_ratio_total %g full_wh_ratio_var %g\n", stats->full_wh_ratio, stats->full_wh_ratio_total, stats->full_wh_ratio_var); } stats->shape_cost = FixedPitchWidthCost(wh_ratio, right_gap, end_row, max_char_wh_ratio); // For some reason Tesseract prefers to treat the whole CJ words // as one blob when the initial segmentation is particularly bad. // This hack is to avoid favoring such states. if (col == 0 && end_row && wh_ratio > max_char_wh_ratio) { stats->shape_cost += 10; } stats->shape_cost += stats->full_wh_ratio_var; if (debug) tprintf("shape_cost %g\n", stats->shape_cost); } }
static float tesseract::AssociateUtils::FixedPitchGapCost | ( | float | norm_gap, |
bool | end_pos | ||
) | [inline, static] |
Definition at line 118 of file associate.h.
{
return (norm_gap < 0.05 && !end_pos) ? 5.0f : 0.0f;
}
float tesseract::AssociateUtils::FixedPitchWidthCost | ( | float | norm_width, |
float | right_gap, | ||
bool | end_pos, | ||
float | max_char_wh_ratio | ||
) | [static] |
Definition at line 160 of file associate.cpp.
{ float cost = 0.0f; if (norm_width > max_char_wh_ratio) cost += norm_width; if (norm_width > kMaxFixedPitchCharAspectRatio) cost += norm_width * norm_width; // extra penalty for merging CJK chars // Penalize skinny blobs, except for punctuation in the last position. if (norm_width+right_gap < 0.5f && !end_pos) { cost += 1.0f - (norm_width + right_gap); } return cost; }
const float tesseract::AssociateUtils::kMaxFixedPitchCharAspectRatio = 2.0f [static] |
Definition at line 71 of file associate.h.
const float tesseract::AssociateUtils::kMinGap = 0.03f [static] |
Definition at line 72 of file associate.h.