Patent ID: 8390826

Claim:
A method for optically inspecting a part having a length, a diameter and an axis, the method comprising: supporting the part; linearly scanning at least one plane of radiation having a width wider than the diameter of the part onto an exterior side surface of the supported part so that the part occludes the at least one plane of radiation at a plurality of spaced apart locations along the axis to create unobstructed left and right planar portions of the at least one plane of radiation passing by and not blocked by the part wherein the unobstructed left and right planar portions contain an amount of radiation which is representative of a respective diameter of the part at the plurality of spaced apart locations; measuring the amount of radiation present in the unobstructed left and right planar portions during the step of scanning to obtain measurement signals which represent diameter of the part at each of the plurality of spaced apart locations along the axis; processing the measurement signals to obtain input data; forming a virtual representation of an outer profile of the part in a reference frame based on the input data; providing a virtual representation of an inner bore of a physical gauge in the reference frame, the inner bore having a diameter; determining an interference position between the part and the gauge using the virtual representations wherein the interference position is a position along the axis where the bore diameter is substantially equal to the part diameter; calculating a distance along the axis based on the interference position; and storing the distance.