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RegionPredetectionModes

Parameter RegionPredetectionModes controls how to find a region of interest (ROI) within the image or frame.

{
    "RegionPredetectionModes": [
        {
            "Mode": "RPM_GENERAL_GRAY_CONTRAST", 
            "Sensitivity": 5
        },
        {
            "Mode": "RPM_GENERAL_RGB_CONTRAST", 
            "Sensitivity": 5
        },
        {
            "Mode": "RPM_GENERAL_HSV_CONTRAST", 
            "ForeAndBackgroundColours":"[20,170,10]",
            "WidthRange": "[100, 200]"
        },
        {
            "Mode": "RPM_NEURAL_NETWORK",
            "DetectionModelName": ""
        }        
    ]
}

Parameter Summary

Mode Arguments

Parameter RegionPredetectionModes consist of a group of region predetection mode objects. Each region predetection mode object includes a candidate mode and a series of mode arguments. The mode arguments of the region predetection mode object is shown as follow:

Mode Argument Name	Mode Argument Summary
Mode (Required)	Description Any one in Candidate Mode List as string
	Type String
	Candidate Mode List RPM_SKIP RPM_AUTO RPM_GENERAL RPM_GENERAL_RGB_CONTRAST RPM_GENERAL_GRAY_CONTRAST RPM_GENERAL_HSV_CONTRAST RPM_GRAY_CONSISTENCY
AspectRatioRange (Optional)	Description Specifies one or multiple sets of aspect ratio ranges as a string for filtering the predetected region. Aspect Ratio = BoundingRectHeight/BoundingRectWidth 100*
	Type String
	Substruct Define one range: "[MinAspectRatio, MaxAspectRatio]" Define multiple ranges: "[MinAspectRatio, MaxAspectRatio];[MinAspectRatio, MaxAspectRatio];..."
	Range MinAspectRatio: [0,10000] MaxAspectRatio: [0,10000]
	Valid For RPM_GENERAL_HSV_CONTRAST
FindAccurateBoundary (Optional)	Description Sets whether to enable finding accurate boundary: 0: disable. 1: enable.
	Type int
	Range [0,1]
	Valid For RPM_GENERAL_HSV_CONTRAST RPM_GENERAL_RGB_CONTRAST RPM_GENERAL_GRAY_CONTRAST
ForeAndBackgroundColours (Required by RPM_GENERAL_HSV_CONTRAST )	Description Specifies a set (or multiple sets) of the foreground and background colours used for region predetection algorithm based on HSV colour space:
	Type String
	Substruct Define one range: "[ForegroundColour,BackgroundColour,Tolerance]" Define multiple ranges: "[ForegroundColour,BackgroundColour,Tolerance];[ForegroundColour,BackgroundColour,Tolerance];..."
	Range ForegroundColour: [-1,360] BackgroundColour: [-1,360] Tolerance: [0, 360]
	Valid For RPM_GENERAL_HSV_CONTRAST
HeightRange (Optional)	Description Specifies a set (or multiple sets) of height range for filtering the predetected region. The height is measured by the height of the bounding rect of the predetected region.
	Type String
	Substruct Define one range: "[MinHeight, MaxHeight]" Define multiple ranges: "[MinHeight, MaxHeight];[MinHeight, MaxHeight];..."
	Range MinHeight: [1, 0x7fffffff] MaxHeight: [1, 0x7fffffff]
	Valid For RPM_GENERAL_HSV_CONTRAST
WidthRange (Optional)	Description Specifies a set (or multiple sets) of width range for filtering the predetected region. The width is measured by the width of the bounding rect of the predetected region.
	Type String
	Substruct Define one range: "[MinWidth, MaxWidth]" Define multiple ranges: "[MinWidth, MaxWidth];[MinWidth, MaxWidth];..."
	Range A string value representing height range sets.
	Valid For RPM_GENERAL_HSV_CONTRAST
MinImageDimension (Optional)	Description Sets the minimum image dimension (in pixels) to enable region pre-detection. The library will enable the region pre-detection feature only when the image dimension is larger than the given value.
	Type int
	Range [16384, 0x7fffffff]
	Valid For RPM_GENERAL_HSV_CONTRAST RPM_GENERAL_RGB_CONTRAST RPM_GENERAL_GRAY_CONTRAST
RelativeRegions (Optional)	Description Sets the barcode regions relative to the pre-detected region.
	Type String
	Substruct Define one region: "[Left,Top,Right,Bottom,Index]" Define multiple region: "[Left,Top,Right,Bottom,Index];[Left,Top,Right,Bottom,Index];..."
	Range Left, Top, Right, Bottom: [-10000,10000] Index: [-1,0x7fffffff]
	Valid For RPM_GENERAL_HSV_CONTRAST
	Remarks Parameters Left, Top, Right, Bottom are measured in percentage. Parameter Index points to a specific colour that set in ForeAndBackgroundColours. Set it to -1 to apply the current RelativeRegion to all ForeAndBackgroundColours.
Sensitivity (Optional)	Description Sets the sensitivity used for region predetection algorithm, a larger value means the library will take more effort to detect regions.
	Type int
	Range [1,9]
	Valid For RPM_GENERAL_HSV_CONTRAST RPM_GENERAL_RGB_CONTRAST RPM_GENERAL_GRAY_CONTRAST
SpatialIndexBlockSize (Optional)	Description Sets the spatial index block size used for region predetection algorithm. The block size used for region predetection would be 2 to the power of N. The allowed values of SpatialIndexBlockSize is the power number (N=1,2,3…).
	Type int
	Range [1, 32]
	Default Value 5
	Valid For RPM_GENERAL_HSV_CONTRAST RPM_GENERAL_RGB_CONTRAST RPM_GENERAL_GRAY_CONTRAST
GrayRange (Optional)	Description Sets the target grayscale value range, formatted as [MinGrayValue, MaxGrayValue], for candidate regions.
	Type Int Array
	Range MinGrayValue: [0,255] MaxGrayValue: [0,255]
	Default Value [0,255]
	Valid For RPM_GRAY_CONSISTENCY.
MatchRatio (Optional)	Description Sets the minimum percentage of pixels within a spatial block that must fall into the `GrayRange` for the block to be considered consistent.
	Type Int
	Range [0, 100]
	Default Value 50
	Valid For RPM_GRAY_CONSISTENCY

Default Setting

The default settings of RegionPredetectionModes is:

{
    "RegionPredetectionModes" : 
    [
        {
            "AspectRatioRange" : "[]",
            "FindAccurateBoundary" : 0,
            "ForeAndBackgroundColours" : "[]",
            "HeightRange" : "[]",
            "ImageParameterName" : "",
            "MeasuredByPercentage" : 1,
            "MinImageDimension" : 262144,
            "Mode" : "RPM_GENERAL",
            "RelativeRegions" : "[]",
            "Sensitivity" : 1,
            "SpatialIndexBlockSize" : 5,
            "WidthRange" : "[]"
        }
    ],
}

Candidate Modes Introduction

RPM_SKIP

Skip region pre-detection process.

RPM_AUTO

Lets the library choose a mode automatically.

RPM_GENERAL

Takes the whole image as a region. This mode has the following arguments for further customizing.

RPM_GENERAL_RGB_CONTRAST

Detects region using the general algorithm based on RGB colour contrast. This mode has the following arguments for further customizing.

Available Mode Arguments:

MinImageDimension
Sensitivity
SpatialIndexBlockSize

RPM_GENERAL_GRAY_CONTRAST

Detects region using the general algorithm based on gray contrast. This mode has the following arguments for further customizing.

Available Mode Arguments:

MinImageDimension
Sensitivity
SpatialIndexBlockSize

RPM_GENERAL_HSV_CONTRAST

Detects region using the general algorithm based on HSV colour contrast. This mode has the following arguments for further customizing.

Available Mode Arguments:

AspectRatioRange
FindAccurateBoundary
ForeAndBackgroundColours
HeightRange
WidthRange
RelativeBarcodeRegions
MinImageDimension
Sensitivity
SpatialIndexBlockSize

RPM_GRAY_CONSISTENCY

Detects regions in a grayscale image where pixel values fall within a specified gray range and demonstrate local consistency. This is useful for locating areas with uniform brightness, such as document backgrounds or label zones.

Available Mode Arguments:

GrayRange
MatchRatio

Remarks

Introduced in Dynamsoft Barcode Reader SDK version 11.2.1000 and Dynamsoft Capture Vision version 3.2.1000.