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TextDetectionMode

Parameter TextDetectionMode determines how to detect the text area. For tasks like barcode reading or border detection, the text part is not important; while for the task of text recognition, the results of detected text zone are mandatory.

Example

{
    "TextDetectionMode":
    {
        "Mode": "TTDM_WORD",
        "Direction": "HORIZONTAL",
        "CharHeightRange": [1,1000,1]
    }
}

Parameter Summary

Parameter TextDetectionMode consist of a group of text detection mode objects. Each text detection mode object includes a candidate mode and a series of mode arguments. The mode arguments of the text detection mode object is shown as follow:

Mode Arguments

Mode Argument Name	Mode Argument Summary
Mode (Required)	Description Any one in Candidate Mode List as string
	Type String
	Candidate Mode List TTDM_WORD TTDM_LINE TTDM_LAYOUT TTDM_SKIP
Direction (Optional)	Description Set the direction to perform text zone detection.
	Type String
	Range "HORIZONTAL", "VERTICAL", "OBLIQUE", "UNKNOWN"
	Default Value "UNKNOWN"
	Valid For All modes
CharHeightRange (Optional)	Description Sets the range of letter height in pixel or a percentage. Format: [MinHeight, MaxHeight, ByThousandth]. if ByThousandth=1, the allowed values for MinHeight/MaxHeight=[1, 1000] if ByThousandth=0, the allowed values for MinHeight/MaxHeight=[1, 0x7fffffff]
	Type int array
	Range [1, 0x7fffffff]
	Valid For All modes
MaxSpacingInALine (Optional)	Description Sets the maximum spacing between characters treated as one line.
	Type int
	Range [-1, 0x7fffffff]
	Default Value -1
	Valid For TTDM_LINE
	Remarks -1: means automatically set by the library. It is a percentage value relative to the average letter height of each line.
Sensitivity (Optional)	Description Sets the sensitivity of text detection.
	Type int
	Range [1, 9]
	Valid For All modes
StringLengthRange (Optional)	Description Sets a range to restrict the string length.
	Type int[]
	Range Each member of the array should be in [0, 0x7fffffff]
	Default Value LabelRecognizer: [3,50]. BarcodeReader & DocumentNormalizer: null
	Valid For All modes
LibraryFileName (Optional)	Description Sets the file name of the library to load dynamically.
	Type String
	Range A string value representing file name.
	Default Value ""
	Valid For All modes.
LibraryParameters (Optional)	Description The library must be in the same place with Dynamsoft Barcode Reader Library.
	Type String
	Range A string value representing parameters.
	Default Value ""
	Valid For All modes.

Default Setting

For Barcode Decoding

{
    "TextDetectionMode" : 
    {
        "Mode" : "TTDM_LINE",
        "Direction" : "UNKNOWN",
        "CharHeightRange" : [1, 1000, 1],
        "MaxSpacingInALine" : -1,
        "Sensitivity" : 3
    }
}

For Label Recognizing

{
    "TextDetectionMode" : 
    {
        "Mode" : "TTDM_LINE",
        "Direction" : "HORIZONTAL",
        "CharHeightRange" : [20, 1000, 1],
        "MaxSpacingInALine" : -1,
        "Sensitivity" : 7
    }
}

For Document Scanning

{
    "TextDetectionMode" : 
    {
        "Mode" : "TTDM_WORD",
        "Direction" : "HORIZONTAL",
        "CharHeightRange" : [1, 1000, 1],
        "Sensitivity" : 7
    }
}

Candidate Modes Introduction

TTDM_WORD

Find the text area based on the “word” objects. It is the fastest text detection mode but has the lowest accuracy.

TTDM_LINE

Find the text area based on the “text line” objects. This mode has higher accuracy than the TTDM_WORD. It is currently implemented as the default mode for text line recognizing.

TTDM_LAYOUT

Find the text area based on the layout. A mode with even higher accuracy than the TTDM_LINE. Not supported yet.