do_ocr_single_class_cnnT_do_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnndo_ocr_single_class_cnn (Operator)

Name

do_ocr_single_class_cnnT_do_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnndo_ocr_single_class_cnn — Classify a single character with an CNN-based OCR classifier.

Signature

do_ocr_single_class_cnn(Character, Image : : OCRHandle, Num : Class, Confidence)

Description

do_ocr_single_class_cnndo_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnndo_ocr_single_class_cnn computes the best classification for the character given by the region CharacterCharacterCharacterCharactercharactercharacter and the gray values ImageImageImageImageimageimage with the OCR classifier OCRHandleOCRHandleOCRHandleOCRHandleOCRHandleocrhandle and returns the best NumNumNumNumnumnum classes in ClassClassClassClassclassValclass and the corresponding confidences (probabilities) of the classes in ConfidenceConfidenceConfidenceConfidenceconfidenceconfidence. Because multiple classes may be returned by do_ocr_single_class_cnndo_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnndo_ocr_single_class_cnn, CharacterCharacterCharacterCharactercharactercharacter may only contain a single region (a single character). If multiple characters should be classified in a single call, do_ocr_multi_class_cnndo_ocr_multi_class_cnnDoOcrMultiClassCnnDoOcrMultiClassCnnDoOcrMultiClassCnndo_ocr_multi_class_cnn must be used.

In most cases, do_ocr_multi_class_cnndo_ocr_multi_class_cnnDoOcrMultiClassCnnDoOcrMultiClassCnnDoOcrMultiClassCnndo_ocr_multi_class_cnn should be preferred over do_ocr_single_class_cnndo_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnndo_ocr_single_class_cnn, since do_ocr_multi_class_cnndo_ocr_multi_class_cnnDoOcrMultiClassCnnDoOcrMultiClassCnnDoOcrMultiClassCnndo_ocr_multi_class_cnn is typically faster than a loop with do_ocr_single_class_cnndo_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnndo_ocr_single_class_cnn. Furthermore, the resulting confidences can be interpreted as probabilities. They indicate the uncertainty of a character's classification result. The operator do_ocr_single_class_cnndo_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnndo_ocr_single_class_cnn has to be used if the nth-best class has to be examined explicitly for n greater than one.

A string of the number '\032'"\032""\032""\032""\032""\032" (alternatively displayed as '\0x1A'"\0x1A""\0x1A""\0x1A""\0x1A""\0x1A") in ClassClassClassClassclassValclass signifies that the region has been classified as rejection class.

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

CharacterCharacterCharacterCharactercharactercharacter (input_object) region → object

Character to be recognized.

ImageImageImageImageimageimage (input_object) singlechannelimage → object (byte / uint2)

Gray values of the character.

OCRHandleOCRHandleOCRHandleOCRHandleOCRHandleocrhandle (input_control) ocr_cnn → (handle)

Handle of the OCR classifier.

NumNumNumNumnumnum (input_control) integer-array → (integer)

Number of best classes to determine.

Default value: 1

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

ClassClassClassClassclassValclass (output_control) string(-array) → (string)

Result of classifying the character with the CNN.

ConfidenceConfidenceConfidenceConfidenceconfidenceconfidence (output_control) real(-array) → (real)

Confidence(s) of the class(es) of the character.

Example (HDevelop)

read_image(Image, 'bottle2')
OffsetRow := 100
OffsetCol := 108
read_ocr_class_cnn('Universal_0-9_NoRej.occ', OCRHandle)
* Select each digit and use do_ocr_single_class_cnn to apply OCR
gen_rectangle1(ROI_Date, OffsetRow, OffsetCol, OffsetRow, OffsetCol)
for I := 1 to 6 by 1
  Offset := I % 2 * 10
  smallest_rectangle1(ROI_Date, Row1, Col1, Row2, Col2)
  gen_rectangle1(ROI_Date, OffsetRow, Offset + Col2, OffsetRow + 42, \
  Col2 + Offset + 31)
  do_ocr_single_class_cnn(ROI_Date, Image, OCRHandle, 1, Class, Confidence)
endfor

Result

If the parameters are valid, the operator do_ocr_single_class_cnndo_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnndo_ocr_single_class_cnn returns the value 2 (H_MSG_TRUE). If necessary, an exception is raised.

Possible Predecessors

read_ocr_class_cnnread_ocr_class_cnnReadOcrClassCnnReadOcrClassCnnReadOcrClassCnnread_ocr_class_cnn

Alternatives

do_ocr_multi_class_cnndo_ocr_multi_class_cnnDoOcrMultiClassCnnDoOcrMultiClassCnnDoOcrMultiClassCnndo_ocr_multi_class_cnn

Module

OCR/OCV

Operators