CogLineMaxEdgeDetectionParams.ContrastThreshold Property

CogLineMaxEdgeDetectionParams ContrastThreshold Property

Cognex VisionPro 9.8 SR1

Gets or sets the minimum contrast constraint. Edge points are not created for gradients with a contrast below this value.

Namespace: Cognex.VisionPro.LineMax
Assembly: Cognex.VisionPro.LineMax (in Cognex.VisionPro.LineMax.dll) Version: 75.0.0.0

Syntax

C++

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public double ContrastThreshold { get; set; }

public double ContrastThreshold { get; set; }

Public Property ContrastThreshold As Double 
	Get 
	Set

Public Property ContrastThreshold As Double 
	Get 
	Set

public:
property double ContrastThreshold {
	double get ();
	void set (double value);
}

public:
property double ContrastThreshold {
	double get ();
	void set (double value);
}

Property Value

Type: Double
The absolute contrast in the range 0.0 to 255.0, inclusive. The default is 5.

Events

Event Type	Reason
ICogChangedEvent Changed	Fires when this property changes. The following state flag may be affected: SfContrastThreshold

Event Type

Reason

ICogChangedEvent Changed

Fires when this property changes.

The following state flag may be affected:

SfContrastThreshold

Exceptions

Exception	Condition
ArgumentOutOfRangeException	Thrown if set to a value less than 0.

Remarks

Unlike normalized contrast, which is a measure of relative intensity difference, contrast is a measure of absolute intensity difference. See NormalizedContrastThreshold for information on applying a constraint on the normalized contrast measurement.

The contrast measurement is computed using:

sqrt(g_x² + g_y²)

Where g_x is the gradient contrast in the direction of the x-axis of the input image selected space; and g_y is the contrast in the direction of the y-axis.

Note that the GradientMagnitude of an edge point is the contrast measurement of the edge point.