@spec getDetectShadows(t()) :: boolean() | {:error, String.t()}

Returns the shadow detection flag

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()

Return

• retval: bool

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

Python prototype (for reference only):

getDetectShadows() -> retval

@spec getDist2Threshold(t()) :: number() | {:error, String.t()}

Returns the threshold on the squared distance between the pixel and the sample

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()

Return

• retval: double

The threshold on the squared distance between the pixel and the sample to decide whether a pixel is close to a data sample.

Python prototype (for reference only):

getDist2Threshold() -> retval

@spec getHistory(t()) :: integer() | {:error, String.t()}

Returns the number of last frames that affect the background model

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()

Return

• retval: int

Python prototype (for reference only):

getHistory() -> retval

@spec getkNNSamples(t()) :: integer() | {:error, String.t()}

Returns the number of neighbours, the k in the kNN.

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()

Return

• retval: int

K is the number of samples that need to be within dist2Threshold in order to decide that that pixel is matching the kNN background model.

Python prototype (for reference only):

getkNNSamples() -> retval

@spec getNSamples(t()) :: integer() | {:error, String.t()}

Returns the number of data samples in the background model

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()

Return

• retval: int

Python prototype (for reference only):

getNSamples() -> retval

@spec getShadowThreshold(t()) :: number() | {:error, String.t()}

Returns the shadow threshold

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()

Return

• retval: double

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.

Python prototype (for reference only):

getShadowThreshold() -> retval

@spec getShadowValue(t()) :: integer() | {:error, String.t()}

Returns the shadow value

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()

Return

• retval: int

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.

Python prototype (for reference only):

getShadowValue() -> retval

@spec setDetectShadows(t(), boolean()) :: :ok | {:error, String.t()}

Enables or disables shadow detection

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()
• detectShadows: bool

Python prototype (for reference only):

setDetectShadows(detectShadows) -> None

@spec setDist2Threshold(t(), number()) :: :ok | {:error, String.t()}

Sets the threshold on the squared distance

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()
• dist2Threshold: double

Python prototype (for reference only):

setDist2Threshold(_dist2Threshold) -> None

@spec setHistory(t(), integer()) :: :ok | {:error, String.t()}

Sets the number of last frames that affect the background model

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()
• history: int

Python prototype (for reference only):

setHistory(history) -> None

@spec setkNNSamples(t(), integer()) :: :ok | {:error, String.t()}

Sets the k in the kNN. How many nearest neighbours need to match.

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()
• nkNN: int

Python prototype (for reference only):

setkNNSamples(_nkNN) -> None

@spec setNSamples(t(), integer()) :: :ok | {:error, String.t()}

Sets the number of data samples in the background model.

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()
• nN: int

The model needs to be reinitalized to reserve memory.

Python prototype (for reference only):

setNSamples(_nN) -> None

@spec setShadowThreshold(t(), number()) :: :ok | {:error, String.t()}

Sets the shadow threshold

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()
• threshold: double

Python prototype (for reference only):

setShadowThreshold(threshold) -> None

@spec setShadowValue(t(), integer()) :: :ok | {:error, String.t()}

Sets the shadow value

Positional Arguments

• self: Evision.BackgroundSubtractorKNN.t()
• value: int

Python prototype (for reference only):

setShadowValue(value) -> None