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TwoFramesDifferenceDetector Class
Motion detector based on two continues frames difference.
Inheritance Hierarchy
SystemObject
  Accord.Vision.MotionTwoFramesDifferenceDetector

Namespace:  Accord.Vision.Motion
Assembly:  Accord.Vision (in Accord.Vision.dll) Version: 3.8.0
Syntax
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public class TwoFramesDifferenceDetector : IMotionDetector
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The TwoFramesDifferenceDetector type exposes the following members.

Constructors
  NameDescription
Public methodTwoFramesDifferenceDetector
Initializes a new instance of the TwoFramesDifferenceDetector class.
Public methodTwoFramesDifferenceDetector(Boolean)
Initializes a new instance of the TwoFramesDifferenceDetector class.
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Properties
  NameDescription
Public propertyDifferenceThreshold
Difference threshold value, [1, 255].
Public propertyMotionFrame
Motion frame containing detected areas of motion.
Public propertyMotionLevel
Motion level value, [0, 1].
Public propertySuppressNoise
Suppress noise in video frames or not.
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Methods
  NameDescription
Public methodEquals
Determines whether the specified object is equal to the current object.
(Inherited from Object.)
Protected methodFinalize
Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.
(Inherited from Object.)
Public methodGetHashCode
Serves as the default hash function.
(Inherited from Object.)
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Protected methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Public methodProcessFrame
Process new video frame.
Public methodReset
Reset motion detector to initial state.
Public methodToString
Returns a string that represents the current object.
(Inherited from Object.)
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Extension Methods
  NameDescription
Public Extension MethodHasMethod
Checks whether an object implements a method with the given name.
(Defined by ExtensionMethods.)
Public Extension MethodIsEqual
Compares two objects for equality, performing an elementwise comparison if the elements are vectors or matrices.
(Defined by Matrix.)
Public Extension MethodTo(Type)Overloaded.
Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.
(Defined by ExtensionMethods.)
Public Extension MethodToTOverloaded.
Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.
(Defined by ExtensionMethods.)
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Remarks

The class implements the simplest motion detection algorithm, which is based on difference of two continues frames. The difference frame is thresholded and the amount of difference pixels is calculated. To suppress stand-alone noisy pixels erosion morphological operator may be applied, which is controlled by SuppressNoise property.

Although the class may be used on its own to perform motion detection, it is preferred to use it in conjunction with MotionDetector class, which provides additional features and allows to use moton post processing algorithms.

Sample usage:

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// create motion detector
MotionDetector detector = new MotionDetector(
    new TwoFramesDifferenceDetector( ),
    new MotionAreaHighlighting( ) );

// continuously feed video frames to motion detector
while ( ... )
{
    // process new video frame and check motion level
    if ( detector.ProcessFrame( videoFrame ) > 0.02 )
    {
        // ring alarm or do somethng else
    }
}
See Also