Method and apparatus for performing cup earing test

An apparatus and method for testing a drawn metal cup for earing, including using a sensing device operable to obtain a first data set representing the height of the rim portion of the cup by rotating the cup relative to the sensing device and recording rim height data each time the cup rotates a given number of degrees, generating a second data set which represents the first derivative of the first data set, and calculating the percent earing for the cup by using values in the first data set which correspond to zero-crossings in the second data set. The method further includes determining the number of peaks and valleys represented in the first data set by counting the number of zero-crossings in the second data set and, if the number of zero-crossings is less than the known minimum number of peaks and valleys on the cup, incrementally biasing the first data set in a manner which increases the detectability of the peaks and valleys and regenerating the second data set until the number of zero-crossings therein equals the known number of peaks and valleys on the cup.