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tesseract/cube/word_size_model.cpp

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/**********************************************************************
* File: word_size_model.cpp
* Description: Implementation of the Word Size Model Class
* Author: Ahmad Abdulkader
* Created: 2008
*
* (C) Copyright 2008, Google Inc.
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
** http://www.apache.org/licenses/LICENSE-2.0
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*
**********************************************************************/
#include <math.h>
#include <string>
#include <vector>
#include "word_size_model.h"
#include "cube_utils.h"
namespace tesseract {
WordSizeModel::WordSizeModel(CharSet * char_set, bool contextual) {
char_set_ = char_set;
contextual_ = contextual;
}
WordSizeModel::~WordSizeModel() {
for (int fnt = 0; fnt < font_pair_size_models_.size(); fnt++) {
FontPairSizeInfo fnt_info = font_pair_size_models_[fnt];
delete []fnt_info.pair_size_info[0];
delete []fnt_info.pair_size_info;
}
}
WordSizeModel *WordSizeModel::Create(const string &data_file_path,
const string &lang,
CharSet *char_set,
bool contextual) {
WordSizeModel *obj = new WordSizeModel(char_set, contextual);
if (!obj) {
fprintf(stderr, "Cube ERROR (WordSizeModel::Create): unable to allocate "
"new word size model object\n");
return NULL;
}
if (!obj->Init(data_file_path, lang)) {
delete obj;
return NULL;
}
return obj;
}
bool WordSizeModel::Init(const string &data_file_path, const string &lang) {
string stats_file_name;
stats_file_name = data_file_path + lang;
stats_file_name += ".cube.size";
// read file to memory
string str_data;
if (!CubeUtils::ReadFileToString(stats_file_name, &str_data)) {
return false;
}
// split to words
vector<string> tokens;
CubeUtils::SplitStringUsing(str_data, "\t\r\n", &tokens);
if (tokens.size() < 1) {
fprintf(stderr, "Cube ERROR (WordSizeModel::Init): invalid "
"file contents: %s\n", stats_file_name.c_str());
return false;
}
font_pair_size_models_.clear();
// token count per line depends on whether the language is contextual or not
int token_cnt = contextual_ ?
(kExpectedTokenCount + 4) : kExpectedTokenCount;
// the count of size classes depends on whether the language is contextual
// or not. For non contextual languages (Ex: Eng), it is equal to the class
// count. For contextual languages (Ex: Ara), it is equal to the class count
// multiplied by the position count (4: start, middle, final, isolated)
int size_class_cnt = contextual_ ?
(char_set_->ClassCount() * 4) : char_set_->ClassCount();
string fnt_name = "";
for (int tok = 0; tok < tokens.size(); tok += token_cnt) {
// a new font, write the old font data and re-init
if (tok == 0 || fnt_name != tokens[tok]) {
FontPairSizeInfo fnt_info;
fnt_info.pair_size_info = new PairSizeInfo *[size_class_cnt];
if (!fnt_info.pair_size_info) {
fprintf(stderr, "Cube ERROR (WordSizeModel::Init): error allcoating "
"memory for font pair size info\n");
return false;
}
fnt_info.pair_size_info[0] =
new PairSizeInfo[size_class_cnt * size_class_cnt];
if (!fnt_info.pair_size_info[0]) {
fprintf(stderr, "Cube ERROR (WordSizeModel::Init): error allocating "
"memory for font pair size info\n");
return false;
}
memset(fnt_info.pair_size_info[0], 0, size_class_cnt * size_class_cnt *
sizeof(PairSizeInfo));
for (int cls = 1; cls < size_class_cnt; cls++) {
fnt_info.pair_size_info[cls] =
fnt_info.pair_size_info[cls - 1] + size_class_cnt;
}
// strip out path and extension
string stripped_font_name = tokens[tok].substr(0, tokens[tok].find('.'));
string::size_type strt_pos = stripped_font_name.find_last_of("/\\");
if (strt_pos != string::npos) {
fnt_info.font_name = stripped_font_name.substr(strt_pos);
} else {
fnt_info.font_name = stripped_font_name;
}
font_pair_size_models_.push_back(fnt_info);
}
// parse the data
int cls_0;
int cls_1;
double delta_top;
double wid_0;
double hgt_0;
double wid_1;
double hgt_1;
int size_code_0;
int size_code_1;
// read and parse the tokens
if (contextual_) {
int start_0;
int end_0;
int start_1;
int end_1;
// The expected format for a character size bigram is as follows:
// ClassId0<delim>Start-flag0<delim>End-flag0<delim>String0(ignored)
// Width0<delim>Height0<delim>
// ClassId1<delim>Start-flag1<delim>End-flag1<delim>String1(ignored)
// HeightDelta<delim>Width1<delim>Height0<delim>
// In case of non-contextual languages, the Start and End flags are
// omitted
if (sscanf(tokens[tok + 1].c_str(), "%d", &cls_0) != 1 ||
sscanf(tokens[tok + 2].c_str(), "%d", &start_0) != 1 ||
sscanf(tokens[tok + 3].c_str(), "%d", &end_0) != 1 ||
sscanf(tokens[tok + 5].c_str(), "%lf", &wid_0) != 1 ||
sscanf(tokens[tok + 6].c_str(), "%lf", &hgt_0) != 1 ||
sscanf(tokens[tok + 7].c_str(), "%d", &cls_1) != 1 ||
sscanf(tokens[tok + 8].c_str(), "%d", &start_1) != 1 ||
sscanf(tokens[tok + 9].c_str(), "%d", &end_1) != 1 ||
sscanf(tokens[tok + 11].c_str(), "%lf", &delta_top) != 1 ||
sscanf(tokens[tok + 12].c_str(), "%lf", &wid_1) != 1 ||
sscanf(tokens[tok + 13].c_str(), "%lf", &hgt_1) != 1 ||
(start_0 != 0 && start_0 != 1) || (end_0 != 0 && end_0 != 1) ||
(start_1 != 0 && start_1 != 1) || (end_1 != 0 && end_1 != 1)) {
fprintf(stderr, "Cube ERROR (WordSizeModel::Init): bad format at "
"line %d\n", 1 + (tok / token_cnt));
return false;
}
size_code_0 = SizeCode(cls_0, start_0, end_0);
size_code_1 = SizeCode(cls_1, start_1, end_1);
} else {
if (sscanf(tokens[tok + 1].c_str(), "%d", &cls_0) != 1 ||
sscanf(tokens[tok + 3].c_str(), "%lf", &wid_0) != 1 ||
sscanf(tokens[tok + 4].c_str(), "%lf", &hgt_0) != 1 ||
sscanf(tokens[tok + 5].c_str(), "%d", &cls_1) != 1 ||
sscanf(tokens[tok + 7].c_str(), "%lf", &delta_top) != 1 ||
sscanf(tokens[tok + 8].c_str(), "%lf", &wid_1) != 1 ||
sscanf(tokens[tok + 9].c_str(), "%lf", &hgt_1) != 1) {
fprintf(stderr, "Cube ERROR (WordSizeModel::Init): bad format at "
"line %d\n", 1 + (tok / token_cnt));
return false;
}
size_code_0 = cls_0;
size_code_1 = cls_1;
}
// copy the data to the size tables
FontPairSizeInfo fnt_info = font_pair_size_models_.back();
fnt_info.pair_size_info[size_code_0][size_code_1].delta_top =
static_cast<int>(delta_top * kShapeModelScale);
fnt_info.pair_size_info[size_code_0][size_code_1].wid_0 =
static_cast<int>(wid_0 * kShapeModelScale);
fnt_info.pair_size_info[size_code_0][size_code_1].hgt_0 =
static_cast<int>(hgt_0 * kShapeModelScale);
fnt_info.pair_size_info[size_code_0][size_code_1].wid_1 =
static_cast<int>(wid_1 * kShapeModelScale);
fnt_info.pair_size_info[size_code_0][size_code_1].hgt_1 =
static_cast<int>(hgt_1 * kShapeModelScale);
fnt_name = tokens[tok];
}
return true;
}
int WordSizeModel::Cost(CharSamp **samp_array, int samp_cnt) const {
if (samp_cnt < 2) {
return 0;
}
double best_dist = static_cast<double>(WORST_COST);
int best_fnt = -1;
for (int fnt = 0; fnt < font_pair_size_models_.size(); fnt++) {
const FontPairSizeInfo *fnt_info = &font_pair_size_models_[fnt];
double mean_dist = 0;
int pair_cnt = 0;
for (int smp_0 = 0; smp_0 < samp_cnt; smp_0++) {
int cls_0 = char_set_->ClassID(samp_array[smp_0]->StrLabel());
if (cls_0 < 1) {
continue;
}
// compute size code for samp 0 based on class id and position
int size_code_0;
if (contextual_) {
size_code_0 = SizeCode(cls_0,
samp_array[smp_0]->FirstChar() == 0 ? 0 : 1,
samp_array[smp_0]->LastChar() == 0 ? 0 : 1);
} else {
size_code_0 = cls_0;
}
int char0_height = samp_array[smp_0]->Height();
int char0_width = samp_array[smp_0]->Width();
int char0_top = samp_array[smp_0]->Top();
for (int smp_1 = smp_0 + 1; smp_1 < samp_cnt; smp_1++) {
int cls_1 = char_set_->ClassID(samp_array[smp_1]->StrLabel());
if (cls_1 < 1) {
continue;
}
// compute size code for samp 0 based on class id and position
int size_code_1;
if (contextual_) {
size_code_1 = SizeCode(cls_1,
samp_array[smp_1]->FirstChar() == 0 ? 0 : 1,
samp_array[smp_1]->LastChar() == 0 ? 0 : 1);
} else {
size_code_1 = cls_1;
}
double dist = PairCost(
char0_width, char0_height, char0_top, samp_array[smp_1]->Width(),
samp_array[smp_1]->Height(), samp_array[smp_1]->Top(),
fnt_info->pair_size_info[size_code_0][size_code_1]);
if (dist > 0) {
mean_dist += dist;
pair_cnt++;
}
} // smp_1
} // smp_0
if (pair_cnt == 0) {
continue;
}
mean_dist /= pair_cnt;
if (best_fnt == -1 || mean_dist < best_dist) {
best_dist = mean_dist;
best_fnt = fnt;
}
}
if (best_fnt == -1) {
return static_cast<int>(WORST_COST);
} else {
return static_cast<int>(best_dist);
}
}
double WordSizeModel::PairCost(int width_0, int height_0, int top_0,
int width_1, int height_1, int top_1,
const PairSizeInfo& pair_info) {
double scale_factor = static_cast<double>(pair_info.hgt_0) /
static_cast<double>(height_0);
double dist = 0.0;
if (scale_factor > 0) {
double norm_width_0 = width_0 * scale_factor;
double norm_width_1 = width_1 * scale_factor;
double norm_height_1 = height_1 * scale_factor;
double norm_delta_top = (top_1 - top_0) * scale_factor;
// accumulate the distance between the model character and the
// predicted one on all dimensions of the pair
dist += fabs(pair_info.wid_0 - norm_width_0);
dist += fabs(pair_info.wid_1 - norm_width_1);
dist += fabs(pair_info.hgt_1 - norm_height_1);
dist += fabs(pair_info.delta_top - norm_delta_top);
}
return dist;
}
} // namespace tesseract
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