Operator Reference
do_ocr_multi_class_cnn (Operator)
do_ocr_multi_class_cnn
— Classify multiple characters with an CNN-based OCR classifier.
Signature
do_ocr_multi_class_cnn(Character, Image : : OCRHandle : Class, Confidence)
Description
do_ocr_multi_class_cnn
computes the best class for each of
the characters given by the regions Character
and the gray
values Image
with the OCR classifier OCRHandle
and
returns the classes in Class
and the corresponding
confidences (probabilities) of the classes in Confidence
.
In contrast to do_ocr_single_class_cnn
,
do_ocr_multi_class_cnn
can classify multiple characters in
one call, and therefore typically is faster than a loop that uses
do_ocr_single_class_cnn
to classify single characters.
However, do_ocr_multi_class_cnn
can only return the best
class of each character. Because the confidences can be interpreted as
probabilities, it is easier to check whether a character has been
classified with too much uncertainty. This is usually not a disadvantage,
except in cases where the classes overlap so much that in many cases the
second best class must be examined to be able to decide the class of the
character. In these cases, do_ocr_single_class_cnn
should be used.
A string of the number
(alternatively
displayed as ) in
Class
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).
- Automatically parallelized on internal data level.
Parameters
Character
(input_object) region(-array) →
object
Characters to be recognized.
Image
(input_object) singlechannelimage →
object (byte / uint2)
Gray values of the characters.
OCRHandle
(input_control) ocr_cnn →
(handle)
Handle of the OCR classifier.
Class
(output_control) string(-array) →
(string)
Result of classifying the characters with the CNN.
Number of elements: Class == Character
Confidence
(output_control) real(-array) →
(real)
Confidence of the class of the characters.
Number of elements: Confidence == Character
Result
If the parameters are valid, the operator
do_ocr_multi_class_cnn
returns the value 2 (
H_MSG_TRUE)
. If
necessary, an exception is raised.
Possible Predecessors
Alternatives
do_ocr_word_cnn
,
do_ocr_single_class_cnn
Module
OCR/OCV