do_ocr_word_svmT_do_ocr_word_svmDoOcrWordSvmDoOcrWordSvmdo_ocr_word_svm (Operator)

Name

do_ocr_word_svmT_do_ocr_word_svmDoOcrWordSvmDoOcrWordSvmdo_ocr_word_svm — Classify a related group of characters with an OCR classifier.

Signature

do_ocr_word_svm(Character, Image : : OCRHandle, Expression, NumAlternatives, NumCorrections : Class, Word, Score)

Herror T_do_ocr_word_svm(const Hobject Character, const Hobject Image, const Htuple OCRHandle, const Htuple Expression, const Htuple NumAlternatives, const Htuple NumCorrections, Htuple* Class, Htuple* Word, Htuple* Score)

void DoOcrWordSvm(const HObject& Character, const HObject& Image, const HTuple& OCRHandle, const HTuple& Expression, const HTuple& NumAlternatives, const HTuple& NumCorrections, HTuple* Class, HTuple* Word, HTuple* Score)

HTuple HRegion::DoOcrWordSvm(const HImage& Image, const HOCRSvm& OCRHandle, const HString& Expression, Hlong NumAlternatives, Hlong NumCorrections, HString* Word, double* Score) const

HTuple HRegion::DoOcrWordSvm(const HImage& Image, const HOCRSvm& OCRHandle, const char* Expression, Hlong NumAlternatives, Hlong NumCorrections, HString* Word, double* Score) const

HTuple HRegion::DoOcrWordSvm(const HImage& Image, const HOCRSvm& OCRHandle, const wchar_t* Expression, Hlong NumAlternatives, Hlong NumCorrections, HString* Word, double* Score) const   (Windows only)

HTuple HOCRSvm::DoOcrWordSvm(const HRegion& Character, const HImage& Image, const HString& Expression, Hlong NumAlternatives, Hlong NumCorrections, HString* Word, double* Score) const

HTuple HOCRSvm::DoOcrWordSvm(const HRegion& Character, const HImage& Image, const char* Expression, Hlong NumAlternatives, Hlong NumCorrections, HString* Word, double* Score) const

HTuple HOCRSvm::DoOcrWordSvm(const HRegion& Character, const HImage& Image, const wchar_t* Expression, Hlong NumAlternatives, Hlong NumCorrections, HString* Word, double* Score) const   (Windows only)

static void HOperatorSet.DoOcrWordSvm(HObject character, HObject image, HTuple OCRHandle, HTuple expression, HTuple numAlternatives, HTuple numCorrections, out HTuple classVal, out HTuple word, out HTuple score)

HTuple HRegion.DoOcrWordSvm(HImage image, HOCRSvm OCRHandle, string expression, int numAlternatives, int numCorrections, out string word, out double score)

HTuple HOCRSvm.DoOcrWordSvm(HRegion character, HImage image, string expression, int numAlternatives, int numCorrections, out string word, out double score)

def do_ocr_word_svm(character: HObject, image: HObject, ocrhandle: HHandle, expression: str, num_alternatives: int, num_corrections: int) -> Tuple[Sequence[str], str, float]

def do_ocr_word_svm_s(character: HObject, image: HObject, ocrhandle: HHandle, expression: str, num_alternatives: int, num_corrections: int) -> Tuple[str, str, float]

Description

do_ocr_word_svmdo_ocr_word_svmDoOcrWordSvmDoOcrWordSvmDoOcrWordSvmdo_ocr_word_svm works like do_ocr_multi_class_svmdo_ocr_multi_class_svmDoOcrMultiClassSvmDoOcrMultiClassSvmDoOcrMultiClassSvmdo_ocr_multi_class_svm insofar as it computes the best class for each of the characters given by the regions CharacterCharacterCharacterCharactercharactercharacter and the gray values ImageImageImageImageimageimage with the OCR classifier OCRHandleOCRHandleOCRHandleOCRHandleOCRHandleocrhandle, and returns the results in ClassClassClassClassclassValclass.

In contrast to do_ocr_multi_class_svmdo_ocr_multi_class_svmDoOcrMultiClassSvmDoOcrMultiClassSvmDoOcrMultiClassSvmdo_ocr_multi_class_svm, do_ocr_word_svmdo_ocr_word_svmDoOcrWordSvmDoOcrWordSvmDoOcrWordSvmdo_ocr_word_svm treats the group of characters as an entity which yields a WordWordWordWordwordword by concatenating the class names for each character region. This allows to restrict the allowed classification results on a textual level by specifying an ExpressionExpressionExpressionExpressionexpressionexpression describing the expected word.

The ExpressionExpressionExpressionExpressionexpressionexpression may restrict the word to belong to a predefined lexicon created using create_lexiconcreate_lexiconCreateLexiconCreateLexiconCreateLexiconcreate_lexicon or import_lexiconimport_lexiconImportLexiconImportLexiconImportLexiconimport_lexicon, by specifying the name of the lexicon in angular brackets as in '<mylexicon>'"<mylexicon>""<mylexicon>""<mylexicon>""<mylexicon>""<mylexicon>". If the ExpressionExpressionExpressionExpressionexpressionexpression is of any other form, it is interpreted as a regular expression with the same syntax as specified for tuple_regexp_matchtuple_regexp_matchTupleRegexpMatchTupleRegexpMatchTupleRegexpMatchtuple_regexp_match. Note that you will usually want to use an expression of the form '^...$' when using variable quantifiers like '*', to ensure that the entire word is used in the expression. Also note that in contrast to tuple_regexp_matchtuple_regexp_matchTupleRegexpMatchTupleRegexpMatchTupleRegexpMatchtuple_regexp_match, do_ocr_word_svmdo_ocr_word_svmDoOcrWordSvmDoOcrWordSvmDoOcrWordSvmdo_ocr_word_svm does not support passing extra options in an expression tuple.

If the word derived from the best class for each character does not match the ExpressionExpressionExpressionExpressionexpressionexpression, do_ocr_word_svmdo_ocr_word_svmDoOcrWordSvmDoOcrWordSvmDoOcrWordSvmdo_ocr_word_svm attempts to correct it by considering the NumAlternativesNumAlternativesNumAlternativesNumAlternativesnumAlternativesnum_alternatives best classes for each character. The alternatives used are identical to those returned by do_ocr_single_class_svmdo_ocr_single_class_svmDoOcrSingleClassSvmDoOcrSingleClassSvmDoOcrSingleClassSvmdo_ocr_single_class_svm for a single character. It does so by testing all possible corrections for which the classification result is changed for at most NumCorrectionsNumCorrectionsNumCorrectionsNumCorrectionsnumCorrectionsnum_corrections character regions. Note that NumAlternativesNumAlternativesNumAlternativesNumAlternativesnumAlternativesnum_alternatives and NumCorrectionsNumCorrectionsNumCorrectionsNumCorrectionsnumCorrectionsnum_corrections affect the complexity of the algorithm, so that in some cases internal restrictions are made. See the section 'Complexity' below for further information.

In case the ExpressionExpressionExpressionExpressionexpressionexpression is a lexicon and the above procedure did not yield a result, the most similar word in the lexicon is returned as long as it requires less than NumCorrectionsNumCorrectionsNumCorrectionsNumCorrectionsnumCorrectionsnum_corrections edit operations for the correction (see suggest_lexiconsuggest_lexiconSuggestLexiconSuggestLexiconSuggestLexiconsuggest_lexicon).

The resulting word is graded by a ScoreScoreScoreScorescorescore between 0.0 (no correction found) and 1.0 (original word correct). The ScoreScoreScoreScorescorescore is lowered by adding a penalty according to the number of corrected characters and another (minor) penalty depending on how many better classes have been ignored in order to match the ExpressionExpressionExpressionExpressionexpressionexpression:

with num_corr being the actual number of applied corrections and num_alt the total number of discarded alternatives.

Execution Information

Parameters

CharacterCharacterCharacterCharactercharactercharacter (input_object)  region(-array) objectHRegionHObjectHRegionHobject

Characters to be recognized.

ImageImageImageImageimageimage (input_object)  singlechannelimage objectHImageHObjectHImageHobject (byte / uint2)

Gray values of the characters.

OCRHandleOCRHandleOCRHandleOCRHandleOCRHandleocrhandle (input_control)  ocr_svm HOCRSvm, HTupleHHandleHTupleHtuple (handle) (IntPtr) (HHandle) (handle)

Handle of the OCR classifier.

ExpressionExpressionExpressionExpressionexpressionexpression (input_control)  string HTuplestrHTupleHtuple (string) (string) (HString) (char*)

Expression describing the allowed word structure.

NumAlternativesNumAlternativesNumAlternativesNumAlternativesnumAlternativesnum_alternatives (input_control)  integer HTupleintHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Number of classes per character considered for the internal word correction.

Default value: 3

Suggested values: 3, 4, 5

Typical range of values: 1 ≤ NumAlternatives NumAlternatives NumAlternatives NumAlternatives numAlternatives num_alternatives

NumCorrectionsNumCorrectionsNumCorrectionsNumCorrectionsnumCorrectionsnum_corrections (input_control)  integer HTupleintHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Maximum number of corrected characters.

Default value: 2

Suggested values: 1, 2, 3, 4, 5

Typical range of values: 0 ≤ NumCorrections NumCorrections NumCorrections NumCorrections numCorrections num_corrections

ClassClassClassClassclassValclass (output_control)  string(-array) HTupleSequence[str]HTupleHtuple (string) (string) (HString) (char*)

Result of classifying the characters with the SVM.

Number of elements: Class == Character

WordWordWordWordwordword (output_control)  string HTuplestrHTupleHtuple (string) (string) (HString) (char*)

Word text after classification and correction.

ScoreScoreScoreScorescorescore (output_control)  real HTuplefloatHTupleHtuple (real) (double) (double) (double)

Measure of similarity between corrected word and uncorrected classification results.

Complexity

The complexity of checking all possible corrections is of magnitude , where a is the number of alternatives, n is the number of character regions, and c is the number of allowed corrections. However, to guard against a near-infinite loop in case of large n, c is internally clipped to 5, 3, or 1 if a*n >= 30, 60, or 90, respectively.

Result

If the parameters are valid, the operator do_ocr_word_svmdo_ocr_word_svmDoOcrWordSvmDoOcrWordSvmDoOcrWordSvmdo_ocr_word_svm returns the value TRUE. If necessary an exception is raised.

Possible Predecessors

trainf_ocr_class_svmtrainf_ocr_class_svmTrainfOcrClassSvmTrainfOcrClassSvmTrainfOcrClassSvmtrainf_ocr_class_svm, read_ocr_class_svmread_ocr_class_svmReadOcrClassSvmReadOcrClassSvmReadOcrClassSvmread_ocr_class_svm

Alternatives

do_ocr_multi_class_svmdo_ocr_multi_class_svmDoOcrMultiClassSvmDoOcrMultiClassSvmDoOcrMultiClassSvmdo_ocr_multi_class_svm

See also

create_ocr_class_svmcreate_ocr_class_svmCreateOcrClassSvmCreateOcrClassSvmCreateOcrClassSvmcreate_ocr_class_svm, classify_class_svmclassify_class_svmClassifyClassSvmClassifyClassSvmClassifyClassSvmclassify_class_svm

Module

OCR/OCV