- Edges in an image detected and placed in a database.
- Crater rim edges are selected from the edge database.
- Edges that belong to the same crater are grouped together.
- An ellipse is fitted to each group of crater edges.
- Ellipses are refined directly in the image domain to reduce errors introduced in the detection of edges and fitting of ellipses.
- The quality of each detected crater is evaluated.
It is planned to utilize this algorithm as the basis of a computer program for automated, real-time, onboard processing of crater-image data. Experimental studies have led to the conclusion that this algorithm is capable of a detection rate >93 percent, a false-alarm rate <5 percent, a geometric error <0.5 pixel, and a position error <0.3 pixel.