Patent ID: 8620033

Claim:
A surface measurement method using a computer system, comprising: inspecting a plurality of samples of a first irregular workpiece surface in two dimensions, each of the plurality of samples having substantially the same size; determining with the computer system, based on the inspections of the samples, a total number of surface peaks on each of the plurality of samples; deriving a control limit with the computer system from a statistical variation of the total number of surface peaks on each of the plurality of samples, the control limit for specifying an out-of-tolerance condition for the total number of surface peaks on a second irregular workpiece surface; inspecting a portion of the second irregular workpiece surface in two dimensions, the portion having substantially the same size as one of the plurality of samples; determining with the computer system, based on the inspection of the portion of the second irregular workpiece surface, a total number of surface peaks on the portion; and comparing with the computer system the total number of surface peaks on the portion to the control limit to determine whether the second irregular workpiece surface is in the out-of-tolerance condition.