Gaussian Mixture-based Background/Foreground Segmentation Algorithm. More...

Inheritance diagram for OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2:

Public Member Functions
int	getHistory ()
	Returns the number of last frames that affect the background model. More...

void	setHistory (int history)
	Sets the number of last frames that affect the background model. More...

int	getNMixtures ()
	Returns the number of gaussian components in the background model. More...

void	setNMixtures (int nmixtures)
	Sets the number of gaussian components in the background model. More...

double	getBackgroundRatio ()
	Returns the "background ratio" parameter of the algorithm. More...

void	setBackgroundRatio (double ratio)
	Sets the "background ratio" parameter of the algorithm. More...

double	getVarThreshold ()
	Returns the variance threshold for the pixel-model match. More...

void	setVarThreshold (double varThreshold)
	Sets the variance threshold for the pixel-model match. More...

double	getVarThresholdGen ()
	Returns the variance threshold for the pixel-model match used for new mixture component generation. More...

void	setVarThresholdGen (double varThresholdGen)
	Sets the variance threshold for the pixel-model match used for new mixture component generation. More...

double	getVarInit ()
	Returns the initial variance of each gaussian component. More...

void	setVarInit (double varInit)
	Sets the initial variance of each gaussian component. More...

double	getVarMin ()

void	setVarMin (double varMin)

double	getVarMax ()

void	setVarMax (double varMax)

double	getComplexityReductionThreshold ()
	Returns the complexity reduction threshold. More...

void	setComplexityReductionThreshold (double ct)
	Sets the complexity reduction threshold. More...

bool	getDetectShadows ()
	Returns the shadow detection flag. More...

void	setDetectShadows (bool detectShadows)
	Enables or disables shadow detection. More...

int	getShadowValue ()
	Returns the shadow value. More...

void	setShadowValue (int value)
	Sets the shadow value. More...

double	getShadowThreshold ()
	Returns the shadow threshold. More...

void	setShadowThreshold (double threshold)
	Sets the shadow threshold. More...

override void	apply (Mat image, Mat fgmask, double learningRate)
	Computes a foreground mask. More...

override void	apply (Mat image, Mat fgmask)
	Computes a foreground mask. More...

Public Member Functions inherited from OpenCVForUnity.VideoModule.BackgroundSubtractor
virtual void	getBackgroundImage (Mat backgroundImage)
	Computes a background image. More...

Public Member Functions inherited from OpenCVForUnity.CoreModule.Algorithm
IntPtr	getNativeObjAddr ()

virtual void	clear ()
	Clears the algorithm state. More...

virtual bool	empty ()
	Returns true if the Algorithm is empty (e.g. in the very beginning or after unsuccessful read. More...

void	save (string filename)

virtual string	getDefaultName ()

Public Member Functions inherited from OpenCVForUnity.DisposableObject
void	Dispose ()

void	ThrowIfDisposed ()

Static Public Member Functions
static new BackgroundSubtractorMOG2	__fromPtr__ (IntPtr addr)

Static Public Member Functions inherited from OpenCVForUnity.VideoModule.BackgroundSubtractor
static new BackgroundSubtractor	__fromPtr__ (IntPtr addr)

Static Public Member Functions inherited from OpenCVForUnity.CoreModule.Algorithm
static Algorithm	__fromPtr__ (IntPtr addr)

Static Public Member Functions inherited from OpenCVForUnity.DisposableObject
static IntPtr	ThrowIfNullIntPtr (IntPtr ptr)

Protected Member Functions
override void	Dispose (bool disposing)

Protected Member Functions inherited from OpenCVForUnity.DisposableOpenCVObject
	DisposableOpenCVObject ()

	DisposableOpenCVObject (IntPtr ptr)

	DisposableOpenCVObject (bool isEnabledDispose)

	DisposableOpenCVObject (IntPtr ptr, bool isEnabledDispose)

Protected Member Functions inherited from OpenCVForUnity.DisposableObject
	DisposableObject ()

	DisposableObject (bool isEnabledDispose)

Additional Inherited Members
Properties inherited from OpenCVForUnity.DisposableObject
bool	IsDisposed `[get, protected set]`

bool	IsEnabledDispose `[get, set]`

Detailed Description

Gaussian Mixture-based Background/Foreground Segmentation Algorithm.

The class implements the Gaussian mixture model background subtraction described in [Zivkovic2004] and [Zivkovic2006] .

Member Function Documentation

◆ fromPtr()

static new BackgroundSubtractorMOG2 OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.__fromPtr__ ( IntPtr addr )

static

◆ apply() [1/2]

override void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.apply	(	Mat	image,
		Mat	fgmask,
		double	learningRate
	)

virtual

Computes a foreground mask.

Parameters

image	Next video frame. Floating point frame will be used without scaling and should be in range \([0,255]\).
fgmask	The output foreground mask as an 8-bit binary image.
learningRate	The value between 0 and 1 that indicates how fast the background model is learnt. Negative parameter value makes the algorithm to use some automatically chosen learning rate. 0 means that the background model is not updated at all, 1 means that the background model is completely reinitialized from the last frame.

Reimplemented from OpenCVForUnity.VideoModule.BackgroundSubtractor.

◆ apply() [2/2]

override void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.apply	(	Mat	image,
		Mat	fgmask
	)

virtual

Computes a foreground mask.

Parameters

image	Next video frame. Floating point frame will be used without scaling and should be in range \([0,255]\).
fgmask	The output foreground mask as an 8-bit binary image.
learningRate	The value between 0 and 1 that indicates how fast the background model is learnt. Negative parameter value makes the algorithm to use some automatically chosen learning rate. 0 means that the background model is not updated at all, 1 means that the background model is completely reinitialized from the last frame.

Reimplemented from OpenCVForUnity.VideoModule.BackgroundSubtractor.

◆ Dispose()

override void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.Dispose ( bool disposing )

protectedvirtual

Reimplemented from OpenCVForUnity.VideoModule.BackgroundSubtractor.

◆ getBackgroundRatio()

double OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getBackgroundRatio ( )

Returns the "background ratio" parameter of the algorithm.

If a foreground pixel keeps semi-constant value for about backgroundRatio*history frames, it's considered background and added to the model as a center of a new component. It corresponds to TB parameter in the paper.

◆ getComplexityReductionThreshold()

double OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getComplexityReductionThreshold ( )

Returns the complexity reduction threshold.

This parameter defines the number of samples needed to accept to prove the component exists. CT=0.05 is a default value for all the samples. By setting CT=0 you get an algorithm very similar to the standard Stauffer&Grimson algorithm.

◆ getDetectShadows()

bool OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getDetectShadows ( )

Returns the shadow detection flag.

If true, the algorithm detects shadows and marks them. See createBackgroundSubtractorMOG2 for details.

◆ getHistory()

int OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getHistory ( )

Returns the number of last frames that affect the background model.

◆ getNMixtures()

int OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getNMixtures ( )

Returns the number of gaussian components in the background model.

◆ getShadowThreshold()

double OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getShadowThreshold ( )

Returns the shadow threshold.

A shadow is detected if pixel is a darker version of the background. The shadow threshold (Tau in the paper) is a threshold defining how much darker the shadow can be. Tau= 0.5 means that if a pixel is more than twice darker then it is not shadow. See Prati, Mikic, Trivedi and Cucchiara, Detecting Moving Shadows...*, IEEE PAMI,2003.

◆ getShadowValue()

int OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getShadowValue ( )

Returns the shadow value.

Shadow value is the value used to mark shadows in the foreground mask. Default value is 127. Value 0 in the mask always means background, 255 means foreground.

◆ getVarInit()

double OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getVarInit ( )

Returns the initial variance of each gaussian component.

◆ getVarMax()

double OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getVarMax ( )

◆ getVarMin()

double OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getVarMin ( )

◆ getVarThreshold()

double OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getVarThreshold ( )

Returns the variance threshold for the pixel-model match.

The main threshold on the squared Mahalanobis distance to decide if the sample is well described by the background model or not. Related to Cthr from the paper.

◆ getVarThresholdGen()

double OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.getVarThresholdGen ( )

Returns the variance threshold for the pixel-model match used for new mixture component generation.

Threshold for the squared Mahalanobis distance that helps decide when a sample is close to the existing components (corresponds to Tg in the paper). If a pixel is not close to any component, it is considered foreground or added as a new component. 3 sigma => Tg=3*3=9 is default. A smaller Tg value generates more components. A higher Tg value may result in a small number of components but they can grow too large.

◆ setBackgroundRatio()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setBackgroundRatio ( double ratio )

Sets the "background ratio" parameter of the algorithm.

◆ setComplexityReductionThreshold()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setComplexityReductionThreshold ( double ct )

Sets the complexity reduction threshold.

◆ setDetectShadows()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setDetectShadows ( bool detectShadows )

Enables or disables shadow detection.

◆ setHistory()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setHistory ( int history )

Sets the number of last frames that affect the background model.

◆ setNMixtures()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setNMixtures ( int nmixtures )

Sets the number of gaussian components in the background model.

The model needs to be reinitalized to reserve memory.

◆ setShadowThreshold()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setShadowThreshold ( double threshold )

Sets the shadow threshold.

◆ setShadowValue()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setShadowValue ( int value )

Sets the shadow value.

◆ setVarInit()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setVarInit ( double varInit )

Sets the initial variance of each gaussian component.

◆ setVarMax()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setVarMax ( double varMax )

◆ setVarMin()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setVarMin ( double varMin )

◆ setVarThreshold()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setVarThreshold ( double varThreshold )

Sets the variance threshold for the pixel-model match.

◆ setVarThresholdGen()

void OpenCVForUnity.VideoModule.BackgroundSubtractorMOG2.setVarThresholdGen ( double varThresholdGen )

Sets the variance threshold for the pixel-model match used for new mixture component generation.

The documentation for this class was generated from the following file:

OpenCVForUnity/Assets/OpenCVForUnity/org/opencv/video/BackgroundSubtractorMOG2.cs

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ __fromPtr__()

◆ apply() [1/2]

◆ apply() [2/2]

◆ Dispose()

◆ getBackgroundRatio()

◆ getComplexityReductionThreshold()

◆ getDetectShadows()

◆ getHistory()

◆ getNMixtures()

◆ getShadowThreshold()

◆ getShadowValue()

◆ getVarInit()

◆ getVarMax()

◆ getVarMin()

◆ getVarThreshold()

◆ getVarThresholdGen()

◆ setBackgroundRatio()

◆ setComplexityReductionThreshold()

◆ setDetectShadows()

◆ setHistory()

◆ setNMixtures()

◆ setShadowThreshold()

◆ setShadowValue()

◆ setVarInit()

◆ setVarMax()

◆ setVarMin()

◆ setVarThreshold()

◆ setVarThresholdGen()

◆ fromPtr()