Position camera🔗

Calculates the position of a matrix camera with respect to the world coordinate system. The tool needs a picture of VisionAppster matrix camera calibration plate, which is taken with a calibrated camera. It is important that the intrinsic calibration parameters in the image are correct. See CalibrateCameraTool.

The tool will detect the origin of the calibration plate and use that as the origin of the world coordinate system for the image output. It is possible to adjust the position of the world origin using the worldFrame input parameter.

Inputs🔗

  • image: A picture of the standard VisionAppster matrix camera calibration plate taken with a calibrated camera. The image may be obtained directly from a calibrated camera or from a .kuva file. Other file formats don’t contain calibration information.

  • markerSpacing: The spacing (distance between centers) of calibration markers on the calibration plate in world units.

  • markerRows: Number of marker rows on the calibration plate. A row is a sequence of markers along the long edge of the plate. The number must be odd.

  • markerColumns: Number of marker columns on the calibration plate A columns is a sequence of markers along the short edge of the plate. The number must be odd.

  • worldFrame: The position of the world coordinate system in the coordinate system of the calibration plate. Note that the input image does not yet contain a valid world coordinate system. This frame is only valid in the context of the new world coordinate system, which is present in the image output.

Outputs🔗

  • image: The input image with the calibration plate’s coordinate system attached.

  • frame: The position of the calibration plate in the camera coordinate system. Drawing this frame on top of an image using its world coordinate system is not meaningful. Similarly, this frame does not work as an input to tools that expect a frame in the world coordinate system. To permanently store camera position, this parameter can be copied to the frame input parameter of Image Source. This will move the world origin to the center of the calibration plate.

  • worldFrame: The position of the world coordinate frame in the camera coordinate system. Drawing this frame on top of an image using its world coordinate system is not meaningful. Similarly, this frame does not work as an input to tools that expect a frame in the world coordinate system. To permanently store camera position, this parameter can be copied to the frame input parameter of Image Source. This will move the world origin to the place defined by the worldFrame input parameter.

  • rotationAngles: A 1-by-3 matrix containing rotation angles of the camera line about Z (roll), Y (yaw) and X (pitch) axes in degrees.

  • detectedMarkerCount: The number of detected markers on the matrix camera calibration plate.

  • errorMeasure: A measure of how successful the positioning procedure was. The smaller the value, the better. A value between 0 and 1 is good, between 1 and 2 is fair and larger than 2 is poor. If the positioning fails completely, the value is infinite. In that case it is likely that the calibration plate was not detected at all.

  • labels: Labeled image in which detected markers are marked with unique integers. The image can be used for checking which markers are possibly missing or disfigured due to poor image quality and make necessary corrections.