do_ocr_word_svm T_do_ocr_word_svm DoOcrWordSvm DoOcrWordSvm do_ocr_word_svm (Operator)
Name
do_ocr_word_svm T_do_ocr_word_svm DoOcrWordSvm DoOcrWordSvm do_ocr_word_svm
— Classify a related group of characters with an OCR classifier.
Signature
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_svm do_ocr_word_svm DoOcrWordSvm DoOcrWordSvm do_ocr_word_svm
works like do_ocr_multi_class_svm do_ocr_multi_class_svm DoOcrMultiClassSvm DoOcrMultiClassSvm do_ocr_multi_class_svm
insofar
as it computes the best class for each of the characters given by the
regions Character Character Character character character
and the gray values Image Image Image image image
with the OCR
classifier OCRHandle OCRHandle OCRHandle OCRHandle ocrhandle
, and returns the results in Class Class Class classVal class
.
In contrast to do_ocr_multi_class_svm do_ocr_multi_class_svm DoOcrMultiClassSvm DoOcrMultiClassSvm do_ocr_multi_class_svm
, do_ocr_word_svm do_ocr_word_svm DoOcrWordSvm DoOcrWordSvm do_ocr_word_svm
treats the group of characters as an entity which yields a Word Word Word word word
by concatenating the class names for each character region. This allows
to restrict the allowed classification results on a textual level by
specifying an Expression Expression Expression expression expression
describing the expected word.
The Expression Expression Expression expression expression
may restrict the word to belong to a predefined
lexicon created using create_lexicon create_lexicon CreateLexicon CreateLexicon create_lexicon
or import_lexicon import_lexicon ImportLexicon ImportLexicon import_lexicon
,
by specifying the name of the lexicon in angular
brackets as in '<mylexicon>' "<mylexicon>" "<mylexicon>" "<mylexicon>" "<mylexicon>" . If the Expression Expression Expression expression expression
is of
any other form, it is interpreted as a regular expression with the same
syntax as specified for tuple_regexp_match tuple_regexp_match TupleRegexpMatch TupleRegexpMatch tuple_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_match tuple_regexp_match TupleRegexpMatch TupleRegexpMatch tuple_regexp_match
, do_ocr_word_svm do_ocr_word_svm DoOcrWordSvm DoOcrWordSvm do_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 Expression Expression Expression expression expression
, do_ocr_word_svm do_ocr_word_svm DoOcrWordSvm DoOcrWordSvm do_ocr_word_svm
attempts to correct it by
considering the NumAlternatives NumAlternatives NumAlternatives numAlternatives num_alternatives
best classes for each character.
The alternatives used are identical to those returned by
do_ocr_single_class_svm do_ocr_single_class_svm DoOcrSingleClassSvm DoOcrSingleClassSvm do_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 NumCorrections NumCorrections NumCorrections numCorrections num_corrections
character regions.
Note that NumAlternatives NumAlternatives NumAlternatives numAlternatives num_alternatives
and NumCorrections NumCorrections NumCorrections numCorrections num_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 Expression Expression Expression expression expression
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 NumCorrections NumCorrections NumCorrections numCorrections num_corrections
edit operations for the
correction (see suggest_lexicon suggest_lexicon SuggestLexicon SuggestLexicon suggest_lexicon
).
The resulting word is graded by a Score Score Score score score
between 0.0 (no correction
found) and 1.0 (original word correct). The Score Score Score score score
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 Expression Expression Expression expression expression
:
with num_corr
being the actual number of applied corrections and
num_alt
the total number of discarded alternatives.
Execution Information
Multithreading type: reentrant (runs in parallel with non-exclusive operators).
Multithreading scope: global (may be called from any thread).
Processed without parallelization.
Parameters
Character Character Character character character
(input_object) region(-array) →
object HRegion HObject HObject Hobject
Characters to be recognized.
Image Image Image image image
(input_object) singlechannelimage →
object HImage HObject HObject Hobject (byte / uint2)
Gray values of the characters.
OCRHandle OCRHandle OCRHandle OCRHandle ocrhandle
(input_control) ocr_svm →
HOCRSvm , HTuple HHandle HTuple Htuple (handle) (IntPtr ) (HHandle ) (handle )
Handle of the OCR classifier.
Expression Expression Expression expression expression
(input_control) string →
HTuple str HTuple Htuple (string) (string ) (HString ) (char* )
Expression describing the allowed word structure.
NumAlternatives NumAlternatives NumAlternatives numAlternatives num_alternatives
(input_control) integer →
HTuple int HTuple Htuple (integer) (int / long) (Hlong ) (Hlong )
Number of classes per character considered for the
internal word correction.
Default:
3
Suggested values:
3, 4, 5
Value range:
1
≤
NumAlternatives
NumAlternatives
NumAlternatives
numAlternatives
num_alternatives
NumCorrections NumCorrections NumCorrections numCorrections num_corrections
(input_control) integer →
HTuple int HTuple Htuple (integer) (int / long) (Hlong ) (Hlong )
Maximum number of corrected characters.
Default:
2
Suggested values:
1, 2, 3, 4, 5
Value range:
0
≤
NumCorrections
NumCorrections
NumCorrections
numCorrections
num_corrections
Class Class Class classVal class
(output_control) string(-array) →
HTuple Sequence[str] HTuple Htuple (string) (string ) (HString ) (char* )
Result of classifying the characters with the
SVM.
Number of elements:
Class == Character
Word Word Word word word
(output_control) string →
HTuple str HTuple Htuple (string) (string ) (HString ) (char* )
Word text after classification and correction.
Score Score Score score score
(output_control) real →
HTuple float HTuple Htuple (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_svm do_ocr_word_svm DoOcrWordSvm DoOcrWordSvm do_ocr_word_svm
returns the value 2 (
H_MSG_TRUE )
. If
necessary an exception is raised.
Possible Predecessors
trainf_ocr_class_svm trainf_ocr_class_svm TrainfOcrClassSvm TrainfOcrClassSvm trainf_ocr_class_svm
,
read_ocr_class_svm read_ocr_class_svm ReadOcrClassSvm ReadOcrClassSvm read_ocr_class_svm
Alternatives
do_ocr_multi_class_svm do_ocr_multi_class_svm DoOcrMultiClassSvm DoOcrMultiClassSvm do_ocr_multi_class_svm
See also
create_ocr_class_svm create_ocr_class_svm CreateOcrClassSvm CreateOcrClassSvm create_ocr_class_svm
,
classify_class_svm classify_class_svm ClassifyClassSvm ClassifyClassSvm classify_class_svm
Module
OCR/OCV