Tesseract 3.02

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tesseract::TesseractCubeCombiner Class Reference

`#include <tesseract_cube_combiner.h>`

List of all members.

## Public Member Functions
| TesseractCubeCombiner (CubeRecoContext *cube_cntxt)
virtual | ~TesseractCubeCombiner ()
float | CombineResults (WERD_RES *tess_res, CubeObject *cube_obj)
float | CombineResults (WERD_RES *tess_res, CubeObject *cube_obj, WordAltList *alt_list)
bool | ComputeCombinerFeatures (const string &tess_res, int tess_confidence, CubeObject *cube_obj, WordAltList *cube_alt_list, vector< double > *features, bool *agreement)
bool | ValidWord (const string &str)
bool | LoadCombinerNet ()

## Detailed Description

Definition at line 47 of file tesseract_cube_combiner.h.

## Constructor & Destructor Documentation

tesseract::TesseractCubeCombiner::TesseractCubeCombiner | ( | CubeRecoContext * | cube_cntxt | ) |
| explicit

Definition at line 39 of file tesseract_cube_combiner.cpp.

{
cube_cntxt_ = cube_cntxt;
combiner_net_ = NULL;
}

tesseract::TesseractCubeCombiner::~TesseractCubeCombiner | ( |  | ) |
| virtual

Definition at line 44 of file tesseract_cube_combiner.cpp.

{
if (combiner_net_ != NULL) {
delete combiner_net_;
combiner_net_ = NULL;
}
}

## Member Function Documentation

float tesseract::TesseractCubeCombiner::CombineResults | ( | WERD_RES * | tess_res,
|  | CubeObject * | cube_obj
| ) |  |

Definition at line 242 of file tesseract_cube_combiner.cpp.

{
// If no combiner is loaded or the cube object is undefined,
// tesseract wins with probability 1.0
if (combiner_net_ == NULL || cube_obj == NULL) {
tprintf("Cube WARNING (TesseractCubeCombiner::CombineResults): "
"Cube objects not initialized; defaulting to Tesseract\n");
return 1.0;
}
// Retrieve the alternate list from the CubeObject's current state.
// If the alt list empty, tesseract wins with probability 1.0
WordAltList *cube_alt_list = cube_obj->AlternateList();
if (cube_alt_list == NULL)
cube_alt_list = cube_obj->RecognizeWord();
if (cube_alt_list == NULL || cube_alt_list->AltCount() <= 0) {
tprintf("Cube WARNING (TesseractCubeCombiner::CombineResults): "
"Cube returned no results; defaulting to Tesseract\n");
return 1.0;
}
return CombineResults(tess_res, cube_obj, cube_alt_list);
}

float tesseract::TesseractCubeCombiner::CombineResults | ( | WERD_RES * | tess_res,
|  | CubeObject * | cube_obj,
|  | WordAltList * | alt_list
| ) |  |

Definition at line 270 of file tesseract_cube_combiner.cpp.

{
// If no combiner is loaded or the cube object is undefined, or the
// alt list is empty, tesseract wins with probability 1.0
if (combiner_net_ == NULL || cube_obj == NULL ||
cube_alt_list == NULL || cube_alt_list->AltCount() <= 0) {
tprintf("Cube WARNING (TesseractCubeCombiner::CombineResults): "
"Cube result cannot be retrieved; defaulting to Tesseract\n");
return 1.0;
}
// Tesseract result string, tesseract confidence, and cost of
// tesseract result according to cube
string tess_str = tess_res->best_choice->unichar_string().string();
// Map certainty [-20.0, 0.0] to confidence [0, 100]
int tess_confidence = MIN(100, MAX(1, static_cast<int>(
100 + (5 * tess_res->best_choice->certainty()))));
// Compute the combiner features. If feature computation fails or
// answers are identical, tesseract wins with probability 1.0
vector<double> features;
bool agreement;
bool combiner_success = ComputeCombinerFeatures(tess_str, tess_confidence,
cube_obj, cube_alt_list,
&features, &agreement);
if (!combiner_success || agreement)
return 1.0;
// Classify combiner feature vector and return output (probability
// of tesseract class).
double net_out[2];
if (!combiner_net_->FeedForward(&features[0], net_out))
return 1.0;
return net_out[1];
}

bool tesseract::TesseractCubeCombiner::ComputeCombinerFeatures | ( | const string & | tess_res,
|  | int | tess_confidence,
|  | CubeObject * | cube_obj,
|  | WordAltList * | cube_alt_list,
|  | vector< double > * | features,
|  | bool * | agreement
| ) |  |

Definition at line 130 of file tesseract_cube_combiner.cpp.

{
features->clear();
*agreement = false;
if (cube_alt_list == NULL || cube_alt_list->AltCount() <= 0)
return false;
// Get Cube's best string; return false if empty
char_32 *cube_best_str32 = cube_alt_list->Alt(0);
if (cube_best_str32 == NULL || CubeUtils::StrLen(cube_best_str32) < 1)
return false;
string cube_best_str;
int cube_best_cost = cube_alt_list->AltCost(0);
int cube_best_bigram_cost = 0;
bool cube_best_bigram_cost_valid = true;
if (cube_cntxt_->Bigrams())
cube_best_bigram_cost = cube_cntxt_->Bigrams()->
Cost(cube_best_str32, cube_cntxt_->CharacterSet());
else
cube_best_bigram_cost_valid = false;
CubeUtils::UTF32ToUTF8(cube_best_str32, &cube_best_str);
// Get Tesseract's UTF32 string
string_32 tess_str32;
CubeUtils::UTF8ToUTF32(tess_str.c_str(), &tess_str32);
// Compute agreement flag
*agreement = (tess_str.compare(cube_best_str) == 0);
// Get Cube's second best string; if empty, return false
char_32 *cube_next_best_str32;
string cube_next_best_str;
int cube_next_best_cost = WORST_COST;
if (cube_alt_list->AltCount() > 1) {
cube_next_best_str32 = cube_alt_list->Alt(1);
if (cube_next_best_str32 == NULL ||
CubeUtils::StrLen(cube_next_best_str32) == 0) {
return false;
}
cube_next_best_cost = cube_alt_list->AltCost(1);
CubeUtils::UTF32ToUTF8(cube_next_best_str32, &cube_next_best_str);
}
// Rank of Tesseract's top result in Cube's alternate list
int tess_rank = 0;
for (tess_rank = 0; tess_rank < cube_alt_list->AltCount(); tess_rank++) {
string alt_str;
CubeUtils::UTF32ToUTF8(cube_alt_list->Alt(tess_rank), &alt_str);
if (alt_str == tess_str)
break;
}
// Cube's cost for tesseract's result. Note that this modifies the
// state of cube_obj, including its alternate list by calling RecognizeWord()
int tess_cost = cube_obj->WordCost(tess_str.c_str());
// Cube's bigram cost of Tesseract's string
int tess_bigram_cost = 0;
int tess_bigram_cost_valid = true;
if (cube_cntxt_->Bigrams())
tess_bigram_cost = cube_cntxt_->Bigrams()->
Cost(tess_str32.c_str(), cube_cntxt_->CharacterSet());
else
tess_bigram_cost_valid = false;
// Tesseract confidence
features->push_back(tess_confidence);
// Cube cost of Tesseract string
features->push_back(tess_cost);
// Cube Rank of Tesseract string
features->push_back(tess_rank);
// length of Tesseract OCR string
features->push_back(tess_str.length());
// Tesseract OCR string in dictionary
features->push_back(ValidWord(tess_str));
if (tess_bigram_cost_valid) {
// bigram cost of Tesseract string
features->push_back(tess_bigram_cost);
}
// Cube tess_cost of Cube best string
features->push_back(cube_best_cost);
// Cube tess_cost of Cube next best string
features->push_back(cube_next_best_cost);
// length of Cube string
features->push_back(cube_best_str.length());
// Cube string in dictionary
features->push_back(ValidWord(cube_best_str));
if (cube_best_bigram_cost_valid) {
// bigram cost of Cube string
features->push_back(cube_best_bigram_cost);
}
// case-insensitive string comparison, including punctuation
int compare_nocase_punc = CompareStrings(cube_best_str.c_str(),
tess_str.c_str(), false, true);
features->push_back(compare_nocase_punc == 0);
// case-sensitive string comparison, ignoring punctuation
int compare_case_nopunc = CompareStrings(cube_best_str.c_str(),
tess_str.c_str(), true, false);
features->push_back(compare_case_nopunc == 0);
// case-insensitive string comparison, ignoring punctuation
int compare_nocase_nopunc = CompareStrings(cube_best_str.c_str(),
tess_str.c_str(), true, true);
features->push_back(compare_nocase_nopunc == 0);
return true;
}

bool tesseract::TesseractCubeCombiner::LoadCombinerNet | ( |  | ) |

Definition at line 51 of file tesseract_cube_combiner.cpp.

{
ASSERT_HOST(cube_cntxt_);
// Compute the path of the combiner net
string data_path;
cube_cntxt_->GetDataFilePath(&data_path);
string net_file_name = data_path + cube_cntxt_->Lang() +
".tesseract_cube.nn";
// Return false if file does not exist
FILE *fp = fopen(net_file_name.c_str(), "rb");
if (fp == NULL)
return false;
else
fclose(fp);
// Load and validate net
combiner_net_ = NeuralNet::FromFile(net_file_name);
if (combiner_net_ == NULL) {
tprintf("Could not read combiner net file %s", net_file_name.c_str());
return false;
} else if (combiner_net_->out_cnt() != 2) {
tprintf("Invalid combiner net file %s! Output count != 2\n",
net_file_name.c_str());
delete combiner_net_;
combiner_net_ = NULL;
return false;
}
return true;
}

bool tesseract::TesseractCubeCombiner::ValidWord | ( | const string & | str | ) |

Definition at line 122 of file tesseract_cube_combiner.cpp.

{
return (cube_cntxt_->TesseractObject()->getDict().valid_word(str.c_str())
> 0);
}

The documentation for this class was generated from the following files:

- /mnt/data/src/tesseract-ocr/ccmain/tesseract_cube_combiner.h
- /mnt/data/src/tesseract-ocr/ccmain/tesseract_cube_combiner.cpp