do_ocr_single_class_cnnT_do_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnn (Operator)

Name

do_ocr_single_class_cnnT_do_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnn — 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_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnn computes the best classification for the character given by the region CharacterCharacterCharacterCharactercharacter and the gray values ImageImageImageImageimage with the OCR classifier OCRHandleOCRHandleOCRHandleOCRHandleOCRHandle and returns the best NumNumNumNumnum classes in ClassClassClassClassclassVal and the corresponding confidences (probabilities) of the classes in ConfidenceConfidenceConfidenceConfidenceconfidence. Because multiple classes may be returned by do_ocr_single_class_cnndo_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnn, CharacterCharacterCharacterCharactercharacter 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_cnnDoOcrMultiClassCnnDoOcrMultiClassCnnDoOcrMultiClassCnn must be used.

In most cases, do_ocr_multi_class_cnndo_ocr_multi_class_cnnDoOcrMultiClassCnnDoOcrMultiClassCnnDoOcrMultiClassCnn should be preferred over do_ocr_single_class_cnndo_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnn, since do_ocr_multi_class_cnndo_ocr_multi_class_cnnDoOcrMultiClassCnnDoOcrMultiClassCnnDoOcrMultiClassCnn is typically faster than a loop with do_ocr_single_class_cnndo_ocr_single_class_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnn. 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_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnn 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" (alternatively displayed as '\0x1A'"\0x1A""\0x1A""\0x1A""\0x1A") in ClassClassClassClassclassVal 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

CharacterCharacterCharacterCharactercharacter (input_object) region → object

Character to be recognized.

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

Gray values of the character.

OCRHandleOCRHandleOCRHandleOCRHandleOCRHandle (input_control) ocr_cnn → (handle)

Handle of the OCR classifier.

NumNumNumNumnum (input_control) integer-array → (integer)

Number of best classes to determine.

Default value: 1

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

ClassClassClassClassclassVal (output_control) string(-array) → (string)

Result of classifying the character with the CNN.

ConfidenceConfidenceConfidenceConfidenceconfidence (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_cnnDoOcrSingleClassCnnDoOcrSingleClassCnnDoOcrSingleClassCnn returns the value 2 (H_MSG_TRUE). If necessary, an exception is raised.

Possible Predecessors

read_ocr_class_cnnread_ocr_class_cnnReadOcrClassCnnReadOcrClassCnnReadOcrClassCnn

Alternatives

do_ocr_multi_class_cnndo_ocr_multi_class_cnnDoOcrMultiClassCnnDoOcrMultiClassCnnDoOcrMultiClassCnn

Module

OCR/OCV

Operators