BackgroundSubtractorMOG2 Properties

Pointer to the unmanaged Algorithm object

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.

Pointer to the unmanaged BackgroundSubtractor object

The maximum variance

If true, the algorithm detects shadows and marks them.

The number of last frames that affect the background model

The number of gaussian components in the background model

Pointer to the unmanaged object

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.

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.

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.

The minimum variance

The initial variance of each gaussian component

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.

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 =%gt