View Source Evision.ArUco.ArucoDetector (Evision v0.1.28)

Link to this section Summary

Types

t()

Type that represents an ArUco.ArucoDetector struct.

Functions

Basic ArucoDetector constructor

Basic ArucoDetector constructor

Clears the algorithm state

Basic marker detection

Basic marker detection

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

getDefaultName

getDetectorParameters

getDictionary

getRefineParameters

Reads algorithm parameters from a file storage

Refind not detected markers based on the already detected and the board layout

Refind not detected markers based on the already detected and the board layout

simplified API for language bindings

Link to this section Types

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

Type that represents an ArUco.ArucoDetector struct.

  • ref. reference()

    The underlying erlang resource variable.

Link to this section Functions

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

Basic ArucoDetector constructor

Keyword Arguments
  • dictionary: Dictionary.

    indicates the type of markers that will be searched

  • detectorParams: DetectorParameters.

    marker detection parameters

  • refineParams: RefineParameters.

    marker refine detection parameters

Return
  • self: Evision.ArUco.ArucoDetector.t()

Python prototype (for reference only):

ArucoDetector([, dictionary[, detectorParams[, refineParams]]]) -> <aruco_ArucoDetector object>
@spec arucoDetector([{atom(), term()}, ...] | nil) :: t() | {:error, String.t()}

Basic ArucoDetector constructor

Keyword Arguments
  • dictionary: Dictionary.

    indicates the type of markers that will be searched

  • detectorParams: DetectorParameters.

    marker detection parameters

  • refineParams: RefineParameters.

    marker refine detection parameters

Return
  • self: Evision.ArUco.ArucoDetector.t()

Python prototype (for reference only):

ArucoDetector([, dictionary[, detectorParams[, refineParams]]]) -> <aruco_ArucoDetector object>
@spec clear(t()) :: t() | {:error, String.t()}

Clears the algorithm state

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()

Python prototype (for reference only):

clear() -> None
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detectMarkers(self, image)

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

Basic marker detection

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()

  • image: Evision.Mat.t().

    input image

Return
  • corners: [Evision.Mat].

    vector of detected marker corners. For each marker, its four corners are provided, (e.g std::vector<std::vector<cv::Point2f> > ). For N detected markers, the dimensions of this array is Nx4. The order of the corners is clockwise.

  • ids: Evision.Mat.t().

    vector of identifiers of the detected markers. The identifier is of type int (e.g. std::vector<int>). For N detected markers, the size of ids is also N. The identifiers have the same order than the markers in the imgPoints array.

  • rejectedImgPoints: [Evision.Mat].

    contains the imgPoints of those squares whose inner code has not a correct codification. Useful for debugging purposes.

Performs marker detection in the input image. Only markers included in the specific dictionary are searched. For each detected marker, it returns the 2D position of its corner in the image and its corresponding identifier. Note that this function does not perform pose estimation. Note: The function does not correct lens distortion or takes it into account. It's recommended to undistort input image with corresponging camera model, if camera parameters are known @sa undistort, estimatePoseSingleMarkers, estimatePoseBoard

Python prototype (for reference only):

detectMarkers(image[, corners[, ids[, rejectedImgPoints]]]) -> corners, ids, rejectedImgPoints
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detectMarkers(self, image, opts)

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

Basic marker detection

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()

  • image: Evision.Mat.t().

    input image

Return
  • corners: [Evision.Mat].

    vector of detected marker corners. For each marker, its four corners are provided, (e.g std::vector<std::vector<cv::Point2f> > ). For N detected markers, the dimensions of this array is Nx4. The order of the corners is clockwise.

  • ids: Evision.Mat.t().

    vector of identifiers of the detected markers. The identifier is of type int (e.g. std::vector<int>). For N detected markers, the size of ids is also N. The identifiers have the same order than the markers in the imgPoints array.

  • rejectedImgPoints: [Evision.Mat].

    contains the imgPoints of those squares whose inner code has not a correct codification. Useful for debugging purposes.

Performs marker detection in the input image. Only markers included in the specific dictionary are searched. For each detected marker, it returns the 2D position of its corner in the image and its corresponding identifier. Note that this function does not perform pose estimation. Note: The function does not correct lens distortion or takes it into account. It's recommended to undistort input image with corresponging camera model, if camera parameters are known @sa undistort, estimatePoseSingleMarkers, estimatePoseBoard

Python prototype (for reference only):

detectMarkers(image[, corners[, ids[, rejectedImgPoints]]]) -> corners, ids, rejectedImgPoints
@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.ArUco.ArucoDetector.t()
Return
  • retval: bool

Python prototype (for reference only):

empty() -> retval
@spec getDefaultName(t()) :: binary() | {:error, String.t()}

getDefaultName

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.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
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getDetectorParameters(self)

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@spec getDetectorParameters(t()) ::
  Evision.ArUco.DetectorParameters.t() | {:error, String.t()}

getDetectorParameters

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()
Return
  • retval: DetectorParameters

Python prototype (for reference only):

getDetectorParameters() -> retval
@spec getDictionary(t()) :: Evision.ArUco.Dictionary.t() | {:error, String.t()}

getDictionary

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()
Return
  • retval: Dictionary

Python prototype (for reference only):

getDictionary() -> retval
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getRefineParameters(self)

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@spec getRefineParameters(t()) ::
  Evision.ArUco.RefineParameters.t() | {:error, String.t()}

getRefineParameters

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()
Return
  • retval: RefineParameters

Python prototype (for reference only):

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

Reads algorithm parameters from a file storage

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()
  • fn_: Evision.FileNode.t()

Python prototype (for reference only):

read(fn_) -> None
Link to this function

refineDetectedMarkers(self, image, board, detectedCorners, detectedIds, rejectedCorners)

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Refind not detected markers based on the already detected and the board layout

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()

  • image: Evision.Mat.t().

    input image

  • board: Board.

    layout of markers in the board.

Keyword Arguments
  • cameraMatrix: Evision.Mat.t().

    optional input 3x3 floating-point camera matrix \f$A = \vecthreethree{f_x}{0}{c_x}{0}{f_y}{c_y}{0}{0}{1}\f$

  • distCoeffs: Evision.Mat.t().

    optional vector of distortion coefficients \f$(k_1, k_2, p_1, p_2[, k_3[, k_4, k_5, k_6],[s_1, s_2, s_3, s_4]])\f$ of 4, 5, 8 or 12 elements

Return
  • detectedCorners: [Evision.Mat].

    vector of already detected marker corners.

  • detectedIds: Evision.Mat.t().

    vector of already detected marker identifiers.

  • rejectedCorners: [Evision.Mat].

    vector of rejected candidates during the marker detection process.

  • recoveredIdxs: Evision.Mat.t().

    Optional array to returns the indexes of the recovered candidates in the original rejectedCorners array.

This function tries to find markers that were not detected in the basic detecMarkers function. First, based on the current detected marker and the board layout, the function interpolates the position of the missing markers. Then it tries to find correspondence between the reprojected markers and the rejected candidates based on the minRepDistance and errorCorrectionRate parameters. If camera parameters and distortion coefficients are provided, missing markers are reprojected using projectPoint function. If not, missing marker projections are interpolated using global homography, and all the marker corners in the board must have the same Z coordinate.

Python prototype (for reference only):

refineDetectedMarkers(image, board, detectedCorners, detectedIds, rejectedCorners[, cameraMatrix[, distCoeffs[, recoveredIdxs]]]) -> detectedCorners, detectedIds, rejectedCorners, recoveredIdxs
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refineDetectedMarkers(self, image, board, detectedCorners, detectedIds, rejectedCorners, opts)

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Refind not detected markers based on the already detected and the board layout

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()

  • image: Evision.Mat.t().

    input image

  • board: Board.

    layout of markers in the board.

Keyword Arguments
  • cameraMatrix: Evision.Mat.t().

    optional input 3x3 floating-point camera matrix \f$A = \vecthreethree{f_x}{0}{c_x}{0}{f_y}{c_y}{0}{0}{1}\f$

  • distCoeffs: Evision.Mat.t().

    optional vector of distortion coefficients \f$(k_1, k_2, p_1, p_2[, k_3[, k_4, k_5, k_6],[s_1, s_2, s_3, s_4]])\f$ of 4, 5, 8 or 12 elements

Return
  • detectedCorners: [Evision.Mat].

    vector of already detected marker corners.

  • detectedIds: Evision.Mat.t().

    vector of already detected marker identifiers.

  • rejectedCorners: [Evision.Mat].

    vector of rejected candidates during the marker detection process.

  • recoveredIdxs: Evision.Mat.t().

    Optional array to returns the indexes of the recovered candidates in the original rejectedCorners array.

This function tries to find markers that were not detected in the basic detecMarkers function. First, based on the current detected marker and the board layout, the function interpolates the position of the missing markers. Then it tries to find correspondence between the reprojected markers and the rejected candidates based on the minRepDistance and errorCorrectionRate parameters. If camera parameters and distortion coefficients are provided, missing markers are reprojected using projectPoint function. If not, missing marker projections are interpolated using global homography, and all the marker corners in the board must have the same Z coordinate.

Python prototype (for reference only):

refineDetectedMarkers(image, board, detectedCorners, detectedIds, rejectedCorners[, cameraMatrix[, distCoeffs[, recoveredIdxs]]]) -> detectedCorners, detectedIds, rejectedCorners, recoveredIdxs
@spec save(t(), binary()) :: t() | {:error, String.t()}

save

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.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
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setDetectorParameters(self, detectorParameters)

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@spec setDetectorParameters(t(), Evision.ArUco.DetectorParameters.t()) ::
  t() | {:error, String.t()}

setDetectorParameters

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()
  • detectorParameters: DetectorParameters

Python prototype (for reference only):

setDetectorParameters(detectorParameters) -> None
Link to this function

setDictionary(self, dictionary)

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@spec setDictionary(t(), Evision.ArUco.Dictionary.t()) :: t() | {:error, String.t()}

setDictionary

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()
  • dictionary: Dictionary

Python prototype (for reference only):

setDictionary(dictionary) -> None
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setRefineParameters(self, refineParameters)

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@spec setRefineParameters(t(), Evision.ArUco.RefineParameters.t()) ::
  t() | {:error, String.t()}

setRefineParameters

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()
  • refineParameters: RefineParameters

Python prototype (for reference only):

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

simplified API for language bindings

Positional Arguments
  • self: Evision.ArUco.ArucoDetector.t()
  • fs: Evision.FileStorage.t()
  • name: String

Python prototype (for reference only):

write(fs, name) -> None