tesseract  4.0.0-1-g2a2b
lm_pain_points.cpp
Go to the documentation of this file.
1 // File: pain_points.cpp
3 // Description: Functions that utilize the knowledge about the properties
4 // of the paths explored by the segmentation search in order
5 // to "pain points" - the locations in the ratings matrix
6 // which should be classified next.
7 // Author: Rika Antonova
8 // Created: Mon Jun 20 11:26:43 PST 2012
9 //
10 // (C) Copyright 2012, Google Inc.
11 // Licensed under the Apache License, Version 2.0 (the "License");
12 // you may not use this file except in compliance with the License.
13 // You may obtain a copy of the License at
14 // http://www.apache.org/licenses/LICENSE-2.0
15 // Unless required by applicable law or agreed to in writing, software
16 // distributed under the License is distributed on an "AS IS" BASIS,
17 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 // See the License for the specific language governing permissions and
19 // limitations under the License.
20 //
22 
23 #include "lm_pain_points.h"
24 
25 #include "associate.h"
26 #include "dict.h"
27 #include "genericheap.h"
28 #include "lm_state.h"
29 #include "matrix.h"
30 #include "pageres.h"
31 
32 #include <algorithm>
33 
34 namespace tesseract {
35 
37 const float LMPainPoints::kLooseMaxCharWhRatio = 2.5f;
38 
40  for (int h = 0; h < LM_PPTYPE_NUM; ++h) {
41  if (pain_points_heaps_[h].empty()) continue;
42  *priority = pain_points_heaps_[h].PeekTop().key;
43  *pp = pain_points_heaps_[h].PeekTop().data;
44  pain_points_heaps_[h].Pop(nullptr);
45  return static_cast<LMPainPointsType>(h);
46  }
47  return LM_PPTYPE_NUM;
48 }
49 
51  MATRIX *ratings = word_res->ratings;
52  AssociateStats associate_stats;
53  for (int col = 0; col < ratings->dimension(); ++col) {
54  int row_end = std::min(ratings->dimension(), col + ratings->bandwidth() + 1);
55  for (int row = col + 1; row < row_end; ++row) {
56  MATRIX_COORD coord(col, row);
57  if (coord.Valid(*ratings) &&
58  ratings->get(col, row) != NOT_CLASSIFIED) continue;
59  // Add an initial pain point if needed.
60  if (ratings->Classified(col, row - 1, dict_->WildcardID()) ||
61  (col + 1 < ratings->dimension() &&
62  ratings->Classified(col + 1, row, dict_->WildcardID()))) {
63  GeneratePainPoint(col, row, LM_PPTYPE_SHAPE, 0.0,
64  true, max_char_wh_ratio_, word_res);
65  }
66  }
67  }
68 }
69 
70 void LMPainPoints::GenerateFromPath(float rating_cert_scale,
71  ViterbiStateEntry *vse,
72  WERD_RES *word_res) {
73  ViterbiStateEntry *curr_vse = vse;
74  BLOB_CHOICE *curr_b = vse->curr_b;
75  // The following pain point generation and priority calculation approaches
76  // prioritize exploring paths with low average rating of the known part of
77  // the path, while not relying on the ratings of the pieces to be combined.
78  //
79  // A pain point to combine the neighbors is generated for each pair of
80  // neighboring blobs on the path (the path is represented by vse argument
81  // given to GenerateFromPath()). The priority of each pain point is set to
82  // the average rating (per outline length) of the path, not including the
83  // ratings of the blobs to be combined.
84  // The ratings of the blobs to be combined are not used to calculate the
85  // priority, since it is not possible to determine from their magnitude
86  // whether it will be beneficial to combine the blobs. The reason is that
87  // chopped junk blobs (/ | - ') can have very good (low) ratings, however
88  // combining them will be beneficial. Blobs with high ratings might be
89  // over-joined pieces of characters, but also could be blobs from an unseen
90  // font or chopped pieces of complex characters.
91  while (curr_vse->parent_vse != nullptr) {
92  ViterbiStateEntry* parent_vse = curr_vse->parent_vse;
93  const MATRIX_COORD& curr_cell = curr_b->matrix_cell();
94  const MATRIX_COORD& parent_cell = parent_vse->curr_b->matrix_cell();
95  MATRIX_COORD pain_coord(parent_cell.col, curr_cell.row);
96  if (!pain_coord.Valid(*word_res->ratings) ||
97  !word_res->ratings->Classified(parent_cell.col, curr_cell.row,
98  dict_->WildcardID())) {
99  // rat_subtr contains ratings sum of the two adjacent blobs to be merged.
100  // rat_subtr will be subtracted from the ratings sum of the path, since
101  // the blobs will be joined into a new blob, whose rating is yet unknown.
102  float rat_subtr = curr_b->rating() + parent_vse->curr_b->rating();
103  // ol_subtr contains the outline length of the blobs that will be joined.
104  float ol_subtr =
105  AssociateUtils::ComputeOutlineLength(rating_cert_scale, *curr_b) +
106  AssociateUtils::ComputeOutlineLength(rating_cert_scale,
107  *(parent_vse->curr_b));
108  // ol_dif is the outline of the path without the two blobs to be joined.
109  float ol_dif = vse->outline_length - ol_subtr;
110  // priority is set to the average rating of the path per unit of outline,
111  // not counting the ratings of the pieces to be joined.
112  float priority = ol_dif > 0 ? (vse->ratings_sum-rat_subtr)/ol_dif : 0.0;
113  GeneratePainPoint(pain_coord.col, pain_coord.row, LM_PPTYPE_PATH,
114  priority, true, max_char_wh_ratio_, word_res);
115  } else if (debug_level_ > 3) {
116  tprintf("NO pain point (Classified) for col=%d row=%d type=%s\n",
117  pain_coord.col, pain_coord.row,
118  LMPainPointsTypeName[LM_PPTYPE_PATH]);
119  BLOB_CHOICE_IT b_it(word_res->ratings->get(pain_coord.col,
120  pain_coord.row));
121  for (b_it.mark_cycle_pt(); !b_it.cycled_list(); b_it.forward()) {
122  BLOB_CHOICE* choice = b_it.data();
123  choice->print_full();
124  }
125  }
126 
127  curr_vse = parent_vse;
128  curr_b = curr_vse->curr_b;
129  }
130 }
131 
133  ViterbiStateEntry *vse,
134  WERD_RES *word_res) {
135  // Begins and ends in DANGERR vector now record the blob indices as used
136  // by the ratings matrix.
137  for (int d = 0; d < fixpt.size(); ++d) {
138  const DANGERR_INFO &danger = fixpt[d];
139  // Only use dangerous ambiguities.
140  if (danger.dangerous) {
141  GeneratePainPoint(danger.begin, danger.end - 1,
142  LM_PPTYPE_AMBIG, vse->cost, true,
143  kLooseMaxCharWhRatio, word_res);
144  }
145  }
146 }
147 
149  int col, int row, LMPainPointsType pp_type, float special_priority,
150  bool ok_to_extend, float max_char_wh_ratio,
151  WERD_RES *word_res) {
152  MATRIX_COORD coord(col, row);
153  if (coord.Valid(*word_res->ratings) &&
154  word_res->ratings->Classified(col, row, dict_->WildcardID())) {
155  return false;
156  }
157  if (debug_level_ > 3) {
158  tprintf("Generating pain point for col=%d row=%d type=%s\n",
159  col, row, LMPainPointsTypeName[pp_type]);
160  }
161  // Compute associate stats.
162  AssociateStats associate_stats;
163  AssociateUtils::ComputeStats(col, row, nullptr, 0, fixed_pitch_,
164  max_char_wh_ratio, word_res, debug_level_,
165  &associate_stats);
166  // For fixed-pitch fonts/languages: if the current combined blob overlaps
167  // the next blob on the right and it is ok to extend the blob, try extending
168  // the blob until there is no overlap with the next blob on the right or
169  // until the width-to-height ratio becomes too large.
170  if (ok_to_extend) {
171  while (associate_stats.bad_fixed_pitch_right_gap &&
172  row + 1 < word_res->ratings->dimension() &&
173  !associate_stats.bad_fixed_pitch_wh_ratio) {
174  AssociateUtils::ComputeStats(col, ++row, nullptr, 0, fixed_pitch_,
175  max_char_wh_ratio, word_res, debug_level_,
176  &associate_stats);
177  }
178  }
179  if (associate_stats.bad_shape) {
180  if (debug_level_ > 3) {
181  tprintf("Discarded pain point with a bad shape\n");
182  }
183  return false;
184  }
185 
186  // Insert the new pain point into pain_points_heap_.
187  if (pain_points_heaps_[pp_type].size() < max_heap_size_) {
188  // Compute pain point priority.
189  float priority;
190  if (pp_type == LM_PPTYPE_PATH) {
191  priority = special_priority;
192  } else {
193  priority = associate_stats.gap_sum;
194  }
195  MatrixCoordPair pain_point(priority, MATRIX_COORD(col, row));
196  pain_points_heaps_[pp_type].Push(&pain_point);
197  if (debug_level_) {
198  tprintf("Added pain point with priority %g\n", priority);
199  }
200  return true;
201  } else {
202  if (debug_level_) tprintf("Pain points heap is full\n");
203  return false;
204  }
205 }
206 
212  for (int i = 0; i < LM_PPTYPE_NUM; ++i) {
213  GenericVector<MatrixCoordPair>* heap = pain_points_heaps_[i].heap();
214  for (int j = 0; j < heap->size(); ++j)
215  (*heap)[j].data.MapForSplit(index);
216  }
217 }
218 
219 } // namespace tesseract
bool GeneratePainPoint(int col, int row, LMPainPointsType pp_type, float special_priority, bool ok_to_extend, float max_char_wh_ratio, WERD_RES *word_res)
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)
Definition: associate.cpp:34
UNICHAR_ID WildcardID() const
Definition: dict.h:413
int size() const
Definition: genericvector.h:71
BLOB_CHOICE * curr_b
Pointers to BLOB_CHOICE and parent ViterbiStateEntry (not owned by this).
Definition: lm_state.h:158
GenericVector< Pair > * heap()
Definition: genericheap.h:83
bool dangerous
Definition: stopper.h:42
void RemapForSplit(int index)
void print_full() const
Definition: ratngs.h:187
bool Valid(const MATRIX &m) const
Definition: matrix.h:615
int bandwidth() const
Definition: matrix.h:535
static const float kDefaultPainPointPriorityAdjustment
#define NOT_CLASSIFIED
Definition: matrix.h:44
int begin
Definition: stopper.h:40
static const float kLooseMaxCharWhRatio
LMPainPointsType Deque(MATRIX_COORD *pp, float *priority)
void GenerateInitial(WERD_RES *word_res)
int dimension() const
Definition: matrix.h:533
const Pair & PeekTop() const
Definition: genericheap.h:108
DLLSYM void tprintf(const char *format,...)
Definition: tprintf.cpp:37
void Push(Pair *entry)
Definition: genericheap.h:95
void GenerateFromPath(float rating_cert_scale, ViterbiStateEntry *vse, WERD_RES *word_res)
const MATRIX_COORD & matrix_cell()
Definition: ratngs.h:115
float rating() const
Definition: ratngs.h:80
static float ComputeOutlineLength(float rating_cert_scale, const BLOB_CHOICE &b)
Definition: associate.h:80
bool Classified(int col, int row, int wildcard_id) const
Definition: matrix.cpp:41
MATRIX * ratings
Definition: pageres.h:231
Definition: matrix.h:575
ViterbiStateEntry * parent_vse
Definition: lm_state.h:159
void GenerateFromAmbigs(const DANGERR &fixpt, ViterbiStateEntry *vse, WERD_RES *word_res)
bool Pop(Pair *entry)
Definition: genericheap.h:118
T get(ICOORD pos) const
Definition: matrix.h:228