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TextLineSpecification Object

Set the CharacterModel, ImageProcessing parameters and other configurations for the specified text lines. This is the parameter that defines how the algorithm extract characters from each text lines of a LabelRecognizer task. You can leave this area empty to use the default character recognizing settings.

{
    "Name":"LS_1",
    "CharacterModelName" : "NumberLetter",
    "ApplicableTextLineNumbers":"",
    "GrayscaleEnhancementModes" : [],
    "BinarizationModes" : [],
    "CharacterNormalizationModes" : [],
    "BaseTextLineSpecificationName" : "LS_0",
    "StringLengthRange" : [44,44],
    "StringRegExPattern" : "",
    "FirstPoint" : [ 0, 0 ],
    "SecondPoint" : [ 100, 0 ],
    "ThirdPoint" : [ 100, 20 ],
    "FourthPoint" : [ 0, 20 ],
    "CharHeightRange" : [ 800, 1000, 1 ]
}

If the number first text line is not in the area, only the third and fifth text lines are processed.

Usage Instructions

Parameter Configurations

Select CharacterModel

Select one of the CharacterModel for the text line(s) by specifying the name of the model. View CharacterModel page for how to configure the models.

Set Targeting Text Lines

Parameter ApplicableTextLineNumbers defines which text lines shall apply the settings of this TextLineSpecification object.

  • If ApplicableTextLineNumbers is null, all the text lines will use the default settings.
  • If ApplicableTextLineNumbers is not applied to all the text lines, the remaining text lines will use the default settings.

You can also specify the location of the targeting text lines with 4 point coordinates. The targeting text line is filtered based on the combination of ApplicableTextLineNumbers and area definition. For example:

text-line-specification

Example Text Line Specification

You can use the following parameters to process the above image:

{
    "ApplicableTextLineNumbers" : "7,8",
    "FirstPoint" : [ 0, 60 ],
    "SecondPoint" : [ 70, 60 ],
    "ThirdPoint" : [ 70, 100 ],
    "FourthPoint" : [ 0, 100 ]
}

If your set the ApplicableTextLineNumbers as “1-8”, the text line from 1 to 6 are not recognized because they are not in the specified area.

Configure ImageProcessing Modes

GrayscaleEnhancementModes enhance the quality of the grayscale image.

BinarizationModes configurations finally reflect in the quality of the binary image. It determines how the charaters are presented on the text areas before they recognized by the library. The higher quality of the binary image, the higher read rate and accuracy of the character recognition result.

CharacterNormalizationModes are additional settings that further improve the quality of characters. Genarally, they are morphological transformations. You can view more about them from Image-Processing in OpenCV - Morphological Transformations.

Quick Settings

Based on a existing TextLineSpecification object, you can use BaseTextLineSpecificationName with other minor changes to configure a new TextLineSpecification object. For example;

{
    "Name":"LS_0",
    "CharacterModelName" : "NumberLetter",
    "ApplicableTextLineNumbers":"1-3",
    "BinarizationModes" : [
        {
            "Mode": "BM_LOCAL_BLOCK",
            "BlockSizeX": 5,
            "BlockSizeY": 5,
        }
    ],
    "CharacterNormalizationModes" : [
        {
            "Mode": "CNM_MORPH",
            "MorphOperation": "Close",
            "MorphArgument": "3",
        }
    ],
    "StringLengthRange" : [44,44],
    "StringRegExPattern" : "Dynamsoft",
    "CharHeightRange" : [ 800, 1000, 1 ]
},
{
    "Name":"LS_1",    
    "BaseTextLineSpecificationName" : "LS_0", // Use the same settings with LS_0 but add some changes.
    "ApplicableTextLineNumbers":"4-7",
    "CharHeightRange" : [ 600, 800, 1 ]
}

Additional Annotations

LabelRecognizerTaskSetting determines how a label recognizer task works from initializing to finializing. As a parameter of LabelRecognizerTaskSetting, TextLineSpecification decides how the text lines are processed when they are detected in the label recognizer task. A group of default settings has been allocated for the TextLineSpecification so that the LabelRecognizerTaskSetting still works without specifying TextLineSpecification parameters.

This page is compatible for:

Version 1.0

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