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

Calculates a sparse optical flow.

Positional Arguments

• self: Evision.SparseOpticalFlow.t()

• prevImg: Evision.Mat.

  First input image.

• nextImg: Evision.Mat.

  Second input image of the same size and the same type as prevImg.

• prevPts: Evision.Mat.

  Vector of 2D points for which the flow needs to be found.

Return

• nextPts: Evision.Mat.t().

  Output vector of 2D points containing the calculated new positions of input features in the second image.

• status: Evision.Mat.t().

  Output status vector. Each element of the vector is set to 1 if the flow for the corresponding features has been found. Otherwise, it is set to 0.

• err: Evision.Mat.t().

  Optional output vector that contains error response for each point (inverse confidence).

Python prototype (for reference only):

calc(prevImg, nextImg, prevPts, nextPts[, status[, err]]) -> nextPts, status, err

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

Calculates a sparse optical flow.

Positional Arguments

• self: Evision.SparseOpticalFlow.t()

• prevImg: Evision.Mat.

  First input image.

• nextImg: Evision.Mat.

  Second input image of the same size and the same type as prevImg.

• prevPts: Evision.Mat.

  Vector of 2D points for which the flow needs to be found.

Return

• nextPts: Evision.Mat.t().

  Output vector of 2D points containing the calculated new positions of input features in the second image.

• status: Evision.Mat.t().

  Output status vector. Each element of the vector is set to 1 if the flow for the corresponding features has been found. Otherwise, it is set to 0.

• err: Evision.Mat.t().

  Optional output vector that contains error response for each point (inverse confidence).

Python prototype (for reference only):

calc(prevImg, nextImg, prevPts, nextPts[, status[, err]]) -> nextPts, status, err

@spec clear(Keyword.t()) :: any() | {:error, String.t()}

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

Clears the algorithm state

Positional Arguments

• self: Evision.SparseOpticalFlow.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.SparseOpticalFlow.t()

Return

• retval: bool

Python prototype (for reference only):

empty() -> retval

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

@spec getDefaultName(t()) :: binary() | {:error, String.t()}

getDefaultName

Positional Arguments

• self: Evision.SparseOpticalFlow.t()

Return

• retval: String

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(t(), Evision.FileNode.t()) :: t() | {:error, String.t()}

Reads algorithm parameters from a file storage

Positional Arguments

• self: Evision.SparseOpticalFlow.t()
• func: Evision.FileNode

Python prototype (for reference only):

read(fn) -> None

@spec save(t(), binary()) :: t() | {:error, String.t()}

save

Positional Arguments

• self: Evision.SparseOpticalFlow.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(t(), Evision.FileStorage.t()) :: t() | {:error, String.t()}

Stores algorithm parameters in a file storage

Positional Arguments

• self: Evision.SparseOpticalFlow.t()
• fs: Evision.FileStorage

Python prototype (for reference only):

write(fs) -> None

@spec write(t(), Evision.FileStorage.t(), binary()) :: t() | {:error, String.t()}

write

Positional Arguments

• self: Evision.SparseOpticalFlow.t()
• fs: Evision.FileStorage
• name: String

Has overloading in C++

Python prototype (for reference only):

write(fs, name) -> None