pyransac3d.circle

Circle Objects

class Circle()

Implementation for Circle RANSAC.

This class finds the circle's parameters based on 3 sampled points. This method uses 3 points to find the circle's plane, center and radius.

Attributes:

• center - Center of the circle, np.array (3,).
• axis - Unit normal vector of the plane which contains the circle, np.array (3,).
• radius - Radius of the circle.
• inliers - Index of the points of pts which fit the circle.
• plane_equation - Equation of the plane which contains the circle, using Ax+By+Cz+D, np.array (4,), where A, B and C are the same as axis.
• plane_distances - Signed distance from each point of pts to the plane of the circle, np.array (N,), in the same order of pts.
• radial_distances - Distance from each point of pts to the hull of the circle if it was extruded along its axis, np.array (N,), in the same order of pts, which is negative for points inside of it.
• distances - Distance from each point of pts to the hull of the circle, np.array (N,), in the same order of pts.

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fit

def fit(pts: NDArray[np.float64],
        thresh: float = 0.2,
        maxIteration: int = 1000,
        callback: Callable[[FitState], bool | None] | None = None
        ) -> CircleResult

Find the parameters (axis and radius and center) to define a circle.

Arguments:

• pts: 3D point cloud as a numpy array (N,3).
• thresh: Threshold distance from the cylinder hull which is considered inlier.
• maxIteration: Number of maximum iteration which RANSAC will loop over.
• callback: Optional callable which receives a FitState after every iteration. Return a truthy value from it to stop the fit early.

Returns:

CircleResult with the center, the axis and the radius of the circle, and its inliers.

Everything else measured while fitting is kept on the object, described in the attributes of this class.

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