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114 lines
3.8 KiB
C++
114 lines
3.8 KiB
C++
///////////////////////////////////////////////////////////////////////
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// File: lm_consistency.cpp
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// Description: Struct for recording consistency of the paths representing
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// OCR hypotheses.
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// Author: Rika Antonova
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// Created: Mon Jun 20 11:26:43 PST 2012
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//
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// (C) Copyright 2012, Google Inc.
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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////////////////////////////////////////////////////////////////////////
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#include "lm_consistency.h"
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#include "associate.h"
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#include "dict.h"
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#include "ratngs.h"
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namespace tesseract {
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void LMConsistencyInfo::ComputeXheightConsistency(
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const BLOB_CHOICE *b, bool is_punc) {
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if (xht_decision == XH_INCONSISTENT)
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return; // It isn't going to get any better.
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// Compute xheight consistency.
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bool parent_null = xht_sp < 0;
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int parent_sp = xht_sp;
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// Debug strings.
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if (b->yshift() > LMConsistencyInfo::kShiftThresh) {
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xht_sp = LMConsistencyInfo::kSUP;
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} else if (b->yshift() < -LMConsistencyInfo::kShiftThresh) {
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xht_sp = LMConsistencyInfo::kSUB;
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} else {
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xht_sp = LMConsistencyInfo::kNORM;
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}
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xht_count[xht_sp]++;
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if (is_punc) xht_count_punc[xht_sp]++;
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if (!parent_null) {
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xpos_entropy += abs(parent_sp - xht_sp);
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}
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// TODO(eger): Figure out a better way to account for small caps.
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// For the first character not y-shifted, we only care if it is too small.
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// Too large is common in drop caps and small caps.
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// int16_t small_xht = b->min_xheight();
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// if (parent_vse == nullptr && sp == LanguageModelConsistencyInfo::kNORM) {
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// small_xht = 0;
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// }
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IntersectRange(b->min_xheight(), b->max_xheight(),
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&(xht_lo[xht_sp]), &(xht_hi[xht_sp]));
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// Compute xheight inconsistency kinds.
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if (parent_null) {
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if (xht_count[kNORM] == 1) {
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xht_decision = XH_GOOD;
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} else {
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xht_decision = XH_SUBNORMAL;
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}
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return;
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}
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// When we intersect the ranges of xheights in pixels for all characters in
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// each position (subscript, normal, superscript),
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// How much range must be left? 0? [exactly one pixel height for xheight] 1?
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// TODO(eger): Extend this code to take a prior for the rest of the line.
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const int kMinIntersectedXHeightRange = 0;
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for (int i = 0; i < kNumPos; i++) {
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if (xht_lo[i] > xht_hi[i] - kMinIntersectedXHeightRange) {
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xht_decision = XH_INCONSISTENT;
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return;
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}
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}
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// Reject as improbable anything where there's much punctuation in subscript
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// or superscript regions.
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if (xht_count_punc[kSUB] > xht_count[kSUB] * 0.4 ||
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xht_count_punc[kSUP] > xht_count[kSUP] * 0.4) {
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xht_decision = XH_INCONSISTENT;
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return;
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}
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// Now check that the subscript and superscript aren't too small relative to
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// the mainline.
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double mainline_xht = static_cast<double>(xht_lo[kNORM]);
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double kMinSizeRatio = 0.4;
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if (mainline_xht > 0.0 &&
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(static_cast<double>(xht_hi[kSUB]) / mainline_xht < kMinSizeRatio ||
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static_cast<double>(xht_hi[kSUP]) / mainline_xht < kMinSizeRatio)) {
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xht_decision = XH_INCONSISTENT;
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return;
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}
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// TODO(eger): Check into inconsistency of super/subscript y offsets.
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if (xpos_entropy > kMaxEntropy) {
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xht_decision = XH_INCONSISTENT;
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return;
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}
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if (xht_count[kSUB] == 0 && xht_count[kSUP] == 0) {
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xht_decision = XH_GOOD;
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return;
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}
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xht_decision = XH_SUBNORMAL;
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}
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} // namespace tesseract
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