raygeo.geo.algo.trace

Contour extraction from binary images.

Provides boundary tracing of foreground regions in a boolean image, returning ordered point loops around each component in pixel coordinates (y increases downward).

Functions

find_external_contours()

find_external_contours(
    boolean_image: numpy.ndarray,
) -> list[list[tuple[float, float]]]

Trace the outer boundary of each foreground region.

Pixels with value 0 are treated as background; non-zero values are foreground. Each contour is an ordered loop of (x, y) points in pixel coordinates; contours with fewer than 3 points are dropped.

Parameter	Type	Description
boolean_image	numpy.ndarray	2D boolean array.
Returns	list[list[tuple[float, float]]]	List of contours, each a list of (x, y) points.
Complexity		O(wh) time, O(wh) space where w*h is the image size