tesseract v5.3.3.20231005
lm_consistency.cpp
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1
2// File: lm_consistency.cpp
3// Description: Struct for recording consistency of the paths representing
4// OCR hypotheses.
5// Author: Rika Antonova
6// Created: Mon Jun 20 11:26:43 PST 2012
7//
8// (C) Copyright 2012, Google Inc.
9// Licensed under the Apache License, Version 2.0 (the "License");
10// you may not use this file except in compliance with the License.
11// You may obtain a copy of the License at
12// http://www.apache.org/licenses/LICENSE-2.0
13// Unless required by applicable law or agreed to in writing, software
14// distributed under the License is distributed on an "AS IS" BASIS,
15// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16// See the License for the specific language governing permissions and
17// limitations under the License.
18//
20
21#include "lm_consistency.h"
22
23#include "associate.h"
24#include "dict.h"
25#include "ratngs.h"
26
27namespace tesseract {
28
31 return; // It isn't going to get any better.
32 }
33
34 // Compute xheight consistency.
35 bool parent_null = xht_sp < 0;
36 int parent_sp = xht_sp;
37 // Debug strings.
40 } else if (b->yshift() < -LMConsistencyInfo::kShiftThresh) {
42 } else {
44 }
46 if (is_punc) {
48 }
49 if (!parent_null) {
50 xpos_entropy += abs(parent_sp - xht_sp);
51 }
52 // TODO(eger): Figure out a better way to account for small caps.
53 // For the first character not y-shifted, we only care if it is too small.
54 // Too large is common in drop caps and small caps.
55 // int16_t small_xht = b->min_xheight();
56 // if (parent_vse == nullptr && sp == LanguageModelConsistencyInfo::kNORM) {
57 // small_xht = 0;
58 // }
60
61 // Compute xheight inconsistency kinds.
62 if (parent_null) {
63 if (xht_count[kNORM] == 1) {
65 } else {
67 }
68 return;
69 }
70
71 // When we intersect the ranges of xheights in pixels for all characters in
72 // each position (subscript, normal, superscript),
73 // How much range must be left? 0? [exactly one pixel height for xheight] 1?
74 // TODO(eger): Extend this code to take a prior for the rest of the line.
75 const int kMinIntersectedXHeightRange = 0;
76 for (int i = 0; i < kNumPos; i++) {
77 if (xht_lo[i] > xht_hi[i] - kMinIntersectedXHeightRange) {
79 return;
80 }
81 }
82
83 // Reject as improbable anything where there's much punctuation in subscript
84 // or superscript regions.
85 if (xht_count_punc[kSUB] > xht_count[kSUB] * 0.4 ||
88 return;
89 }
90
91 // Now check that the subscript and superscript aren't too small relative to
92 // the mainline.
93 auto mainline_xht = static_cast<double>(xht_lo[kNORM]);
94 double kMinSizeRatio = 0.4;
95 if (mainline_xht > 0.0 && (static_cast<double>(xht_hi[kSUB]) / mainline_xht < kMinSizeRatio ||
96 static_cast<double>(xht_hi[kSUP]) / mainline_xht < kMinSizeRatio)) {
98 return;
99 }
100 // TODO(eger): Check into inconsistency of super/subscript y offsets.
103 return;
104 }
105 if (xht_count[kSUB] == 0 && xht_count[kSUP] == 0) {
107 return;
108 }
110}
111
112} // namespace tesseract
@ XH_GOOD
Definition: dict.h:81
@ XH_SUBNORMAL
Definition: dict.h:81
@ XH_INCONSISTENT
Definition: dict.h:81
void IntersectRange(const T &lower1, const T &upper1, T *lower2, T *upper2)
Definition: helpers.h:141
float min_xheight() const
Definition: ratngs.h:124
float yshift() const
Definition: ratngs.h:130
float max_xheight() const
Definition: ratngs.h:127
void ComputeXheightConsistency(const BLOB_CHOICE *b, bool is_punc)
static const int kShiftThresh
int16_t xht_count_punc[kNumPos]
XHeightConsistencyEnum xht_decision
static const int kMaxEntropy