View Source Evision.BackgroundSubtractor (Evision v0.2.9)

Summary

Types

t()

Type that represents an BackgroundSubtractor struct.

Functions

Computes a foreground mask.

Computes a foreground mask.

Clears the algorithm state

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

Computes a background image.

Computes a background image.

Reads algorithm parameters from a file storage

Stores algorithm parameters in a file storage

Types

@type t() :: %Evision.BackgroundSubtractor{ref: reference()}

Type that represents an BackgroundSubtractor struct.

  • ref. reference()

    The underlying erlang resource variable.

Functions

@spec apply(Keyword.t()) :: any() | {:error, String.t()}
@spec apply(t(), Evision.Mat.maybe_mat_in()) :: Evision.Mat.t() | {:error, String.t()}

Computes a foreground mask.

Positional Arguments
  • self: Evision.BackgroundSubtractor.t()

  • image: Evision.Mat.

    Next video frame.

Keyword Arguments
  • learningRate: double.

    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.

Return
  • fgmask: Evision.Mat.t().

    The output foreground mask as an 8-bit binary image.

Python prototype (for reference only):

apply(image[, fgmask[, learningRate]]) -> fgmask
Link to this function

apply(self, image, opts)

View Source
@spec apply(t(), Evision.Mat.maybe_mat_in(), [{:learningRate, term()}] | nil) ::
  Evision.Mat.t() | {:error, String.t()}

Computes a foreground mask.

Positional Arguments
  • self: Evision.BackgroundSubtractor.t()

  • image: Evision.Mat.

    Next video frame.

Keyword Arguments
  • learningRate: double.

    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.

Return
  • fgmask: Evision.Mat.t().

    The output foreground mask as an 8-bit binary image.

Python prototype (for reference only):

apply(image[, fgmask[, learningRate]]) -> fgmask
@spec clear(Keyword.t()) :: any() | {:error, String.t()}
@spec clear(t()) :: t() | {:error, String.t()}

Clears the algorithm state

Positional Arguments
  • self: Evision.BackgroundSubtractor.t()

Python prototype (for reference only):

clear() -> None
@spec empty(Keyword.t()) :: any() | {:error, String.t()}
@spec empty(t()) :: boolean() | {:error, String.t()}

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

Positional Arguments
  • self: Evision.BackgroundSubtractor.t()
Return
  • retval: bool

Python prototype (for reference only):

empty() -> retval
Link to this function

getBackgroundImage(named_args)

View Source
@spec getBackgroundImage(Keyword.t()) :: any() | {:error, String.t()}
@spec getBackgroundImage(t()) :: Evision.Mat.t() | {:error, String.t()}

Computes a background image.

Positional Arguments
  • self: Evision.BackgroundSubtractor.t()
Return
  • backgroundImage: Evision.Mat.t().

    The output background image.

Note: Sometimes the background image can be very blurry, as it contain the average background statistics.

Python prototype (for reference only):

getBackgroundImage([, backgroundImage]) -> backgroundImage
Link to this function

getBackgroundImage(self, opts)

View Source
@spec getBackgroundImage(t(), [{atom(), term()}, ...] | nil) ::
  Evision.Mat.t() | {:error, String.t()}

Computes a background image.

Positional Arguments
  • self: Evision.BackgroundSubtractor.t()
Return
  • backgroundImage: Evision.Mat.t().

    The output background image.

Note: Sometimes the background image can be very blurry, as it contain the average background statistics.

Python prototype (for reference only):

getBackgroundImage([, backgroundImage]) -> backgroundImage
Link to this function

getDefaultName(named_args)

View Source
@spec getDefaultName(Keyword.t()) :: any() | {:error, String.t()}
@spec getDefaultName(t()) :: binary() | {:error, String.t()}

getDefaultName

Positional Arguments
  • self: Evision.BackgroundSubtractor.t()
Return

Returns the algorithm string identifier. This string is used as top level xml/yml node tag when the object is saved to a file or string.

Python prototype (for reference only):

getDefaultName() -> retval
@spec read(Keyword.t()) :: any() | {:error, String.t()}
@spec read(t(), Evision.FileNode.t()) :: t() | {:error, String.t()}

Reads algorithm parameters from a file storage

Positional Arguments

Python prototype (for reference only):

read(fn) -> None
@spec save(Keyword.t()) :: any() | {:error, String.t()}
@spec save(t(), binary()) :: t() | {:error, String.t()}

save

Positional Arguments
  • self: Evision.BackgroundSubtractor.t()
  • filename: String

Saves the algorithm to a file. In order to make this method work, the derived class must implement Algorithm::write(FileStorage& fs).

Python prototype (for reference only):

save(filename) -> None
@spec write(Keyword.t()) :: any() | {:error, String.t()}
@spec write(t(), Evision.FileStorage.t()) :: t() | {:error, String.t()}

Stores algorithm parameters in a file storage

Positional Arguments

Python prototype (for reference only):

write(fs) -> None
@spec write(t(), Evision.FileStorage.t(), binary()) :: t() | {:error, String.t()}

write

Positional Arguments

Has overloading in C++

Python prototype (for reference only):

write(fs, name) -> None