A method for detecting an ellipsoid includes: extracting an ellipsoid
candidate; extracting an ellipsoid contour; calculating an ellipsoid
parameter; calculating an adaptability ratio; and eliminating the
ellipsoid candidate. Extracting the ellipsoid candidate includes:
inputting an image with figures; selecting the ellipsoid candidate from
the figures; and extracting a contour candidate point and a center point.
Extracting the ellipsoid contour includes: drawing straight lines;
determining contour candidate points; calculating first and second
distances; and defining ellipsoid contour points. Calculating the
ellipsoid parameter is based on the ellipsoid contour points and the
center point. Calculating the adaptability ratio includes: drawing a
complete ellipsoid; and calculating the adaptability ratio between the
complete ellipsoid and the ellipsoid candidate. Eliminating the ellipsoid
candidate is performed when the adaptability ratio is equal to or smaller
than a threshold.