/**
* @name call_matcher
*
* Called from Tess with a blob in tess form.
* The blob may need rotating to the correct orientation for classification.
*/
BLOB_CHOICE_LIST *Wordrec::call_matcher(TBLOB *tessblob) {
// Rotate the blob for classification if necessary.
TBLOB* rotated_blob = tessblob->ClassifyNormalizeIfNeeded();
if (rotated_blob == nullptr) {
rotated_blob = tessblob;
}
BLOB_CHOICE_LIST *ratings = new BLOB_CHOICE_LIST(); // matcher result
AdaptiveClassifier(rotated_blob, ratings);
if (rotated_blob != tessblob) {
delete rotated_blob;
}
return ratings;
}
/**
* @name call_matcher
*
* Called from Tess with a blob in tess form.
* The blob may need rotating to the correct orientation for classification.
*/
BLOB_CHOICE_LIST *Wordrec::call_matcher(const DENORM* denorm, TBLOB *tessblob) {
// Rotate the blob for classification if necessary.
TBLOB* rotated_blob = tessblob->ClassifyNormalizeIfNeeded(&denorm);
if (rotated_blob == NULL) {
rotated_blob = tessblob;
}
BLOB_CHOICE_LIST *ratings = new BLOB_CHOICE_LIST(); // matcher result
AdaptiveClassifier(rotated_blob, *denorm, ratings, NULL);
if (rotated_blob != tessblob) {
delete rotated_blob;
delete denorm;
}
return ratings;
}
void Tesseract::tess_bn_matcher( //call tess
PBLOB *pblob, //previous blob
PBLOB *blob, //blob to match
PBLOB *nblob, //next blob
WERD *word, //word it came from
DENORM *denorm, //de-normaliser
BLOB_CHOICE_LIST *ratings //list of results
) {
TBLOB *tessblob; //converted blob
TEXTROW tessrow; //dummy row
tess_bn_matching.set_value(true); //turn it on
tess_cn_matching.set_value(false);
//convert blob
tessblob = make_rotated_tess_blob(denorm, blob, true);
//make dummy row
make_tess_row(denorm, &tessrow);
//classify
AdaptiveClassifier(tessblob, NULL, &tessrow, ratings, NULL);
free_blob(tessblob);
}
void tess_default_matcher( //call tess
PBLOB *pblob, //previous blob
PBLOB *blob, //blob to match
PBLOB *nblob, //next blob
WERD *word, //word it came from
DENORM *denorm, //de-normaliser
BLOB_CHOICE_LIST &ratings //list of results
) {
LIST result; //tess output
TBLOB *tessblob; //converted blob
TEXTROW tessrow; //dummy row
tess_bn_matching = FALSE; //turn it off
tess_cn_matching = FALSE;
//convert blob
tessblob = make_tess_blob (blob, TRUE);
//make dummy row
make_tess_row(denorm, &tessrow);
//classify
result = AdaptiveClassifier (tessblob, NULL, &tessrow);
free_blob(tessblob);
//make our format
convert_choice_list(result, ratings);
}
// Adapt to recognize the current image as the given character.
// The image must be preloaded and be just an image of a single character.
void TessBaseAPI::AdaptToCharacter(const char *unichar_repr,
int length,
float baseline,
float xheight,
float descender,
float ascender) {
UNICHAR_ID id = unicharset.unichar_to_id(unichar_repr, length);
LINE_STATS LineStats;
TEXTROW row;
fill_dummy_row(baseline, xheight, descender, ascender, &row);
GetLineStatsFromRow(&row, &LineStats);
TBLOB *blob = make_tesseract_blob(baseline, xheight, descender, ascender);
float threshold;
int best_class = 0;
float best_rating = -100;
// Classify to get a raw choice.
LIST result = AdaptiveClassifier(blob, NULL, &row);
LIST p;
for (p = result; p != NULL; p = p->next) {
A_CHOICE *tesschoice = (A_CHOICE *) p->node;
if (tesschoice->rating > best_rating) {
best_rating = tesschoice->rating;
best_class = tesschoice->string[0];
}
}
FLOAT32 GetBestRatingFor(TBLOB *Blob, LINE_STATS *LineStats, CLASS_ID ClassId);
// We have to use char-level adaptation because otherwise
// someone should do forced alignment somewhere.
void AdaptToChar(TBLOB *Blob,
LINE_STATS *LineStats,
CLASS_ID ClassId,
FLOAT32 Threshold);
if (id == best_class)
threshold = GoodAdaptiveMatch;
else {
/* the blob was incorrectly classified - find the rating threshold
needed to create a template which will correct the error with
some margin. However, don't waste time trying to make
templates which are too tight. */
threshold = GetBestRatingFor(blob, &LineStats, id);
threshold *= .9;
const float max_threshold = .125;
const float min_threshold = .02;
if (threshold > max_threshold)
threshold = max_threshold;
// I have cuddled the following line to set it out of the strike
// of the coverage testing tool. I have no idea how to trigger
// this situation nor I have any necessity to do it. --mezhirov
if (threshold < min_threshold) threshold = min_threshold;
}
if (blob->outlines)
AdaptToChar(blob, &LineStats, id, threshold);
free_blob(blob);
}