Creates an OCR multilayer perceptron model.
|inNormalizationSize||Size||The character size after normalization|
|inHiddenLayerSizes||IntegerArray*||Internal structure of neuron layers used in classifier|
|inRandomSeed||Integer*||0 - +||Random seed used by MLP classifier|
|inPreprocessing||MlpPreprocessing||Input preprocessing method performed before calculations|
|inCharacterFeatures||CharacterFeatures||Character features used to distinguish characters from each other|
|outOcrModel||OcrMlpModel||Result OcrMlpModel used to recognize characters|
Parameters inHiddenLayerSizes, inRandomSeed are used in the process of learning of a newly created MLP classifier. For further parameter description please refer to the documentation of the MLP_Init filter.
All the input regions in filters RecognizeCharacters_MLP_Deprecated and TrainOcr_MLP_Deprecated will be resized to the size specified in the inNormalizationSize input parameter. The further character classification will be performed on the normalized images. Therefore, it is important to select the appropriate normalization size. The selection of too small normalization size may result in loss of character details. However, too large value of normalization size increases the classifier learning time. The best character recognition accuracy is obtained when the size of character is nearly the same as the classifier normalization size.
The character classification depends on character features that are selected in the inCharacterFeatures parameter. At least one feature must be selected. By default the feature "Pixels" is selected.
The table below contains the description of each available character feature:
|Feature name||Description||Filter origin||Normalized|
|Pixels||Values of the image pixels after normalization.||False|
|NormalizedPixels||Values of the image pixels after normalization normalized to range <0, 1.0>.||True|
|Convexity||Ratio of the input region area to area of its convex hull.||RegionConvexity||True|
|Circularity||Ratio of the region area to area of its bounding circle.||RegionCircularity||True|
|NumberOfHoles||Number of holes found in the input region.||RegionHoles||True|
|AspectRatio||Ratio of input region width to its height.||RegionBoundingBox||False|
|Width||Region bounding box width.||RegionBoundingBox||False|
|Height||Region bounding box height.||RegionBoundingBox||False|
|AreaRatio||Ratio of the input region area to area of its bounding box.||True|
|DiameterRatio||Ratio of the input region diameter to diameter of its bounding box.||RegionDiameter||True|
|Elongation||Ratio of longer axis of the approximating ellipse to the shorter one.||RegionElongation||False|
|Orientation||Further details in the filter RegionOrientation documentation.||RegionOrientation||True|
|Zoning4x4||Normalized pixel values of region reduced to size 4x4 pixel.||True|
|HorizontalProjection||Values of normalized image projection normalized by region height.||ImageProjection||True|
|VerticalProjection||Values of normalized image projection normalized by region height.||ImageProjection||True|
|HoughCircles||Count of circles found in the normalized image.||True|
|Moment_11||Character geometric moment type M11.||RegionMoment||False|
|Moment_20||Character geometric moment type M20.||RegionMoment||False|
|Moment_02||Character geometric moment type M02.||RegionMoment||False|
The table above shows which of the presented character features give normalized results. Learning process of not-normalized data can be a bit slower than learning of normalized data. To reduce this effect the option Normalization should be selected for the input inPreprocessing.
It is recommended not to set normalization size greater than 50 pixels in each dimension. That could make learning time too long.
For more remarks about using MLP classifier please refer to the documentation of the MLP_Init filter.
To read more about how to use OCR technique, refer to Machine Vision Guide: Optical Character Recognition
This filter can throw an exception to report error. Read how to deal with errors in Error Handling.
List of possible exceptions:
|DomainError||Hidden layer should have at least a single hidden layer in InitOcr_MLP_Deprecated.|
|DomainError||Invalid normalization size in InitOcr_MLP_Deprecated.|
This filter is available on Advanced Complexity Level.