Patent ID: 7792654

Claim:
A measurement probe for dimensional measurement of an object, comprising: a stylus having an object contacting area and having a stem extending along a first axis; a stylus contact determination device having a plurality of sensor elements, each sensor element having an output for detecting physical contact of the object by the object contacting area of the stylus; and a processor for processing the outputs of the sensor elements; wherein the outputs of the sensor elements are combined in the processor such that the sensitivity when an object is approached along an approach direction parallel to the first axis is different compared with the sensitivity when an object is approached along an approach direction perpendicular to the first axis, whereby the processor provides an object contact trigger signal caused by a predefined displacement of the stylus object contacting area, the predefined displacement being approximately independent of the approach direction between the measurement probe and the object, and the processor combines the outputs of the sensor elements to form a gauge output (G) according to the algorithm or equation G = 1 α ⁢ { Δ ⁢ ⁢ R 1 2 + Δ ⁢ ⁢ R 2 2 + Δ ⁢ ⁢ R 3 2 + β ⁡ ( Δ ⁢ ⁢ R 1 ⁢ Δ ⁢ ⁢ R 2 + Δ ⁢ ⁢ R 2 ⁢ Δ ⁢ ⁢ R 3 + Δ ⁢ ⁢ R 3 ⁢ Δ ⁢ ⁢ R 1 ) } where the terms ΔR 1 , ΔR 2 and ΔR 3 refer to the outputs of the sensor elements and α and β are scaling factors.