Geometric Tolerance Evaluation Using Combined Vision – Contact Techniques and Other Data Fusion Approaches

Abstract

The development of ever-pressing requirements for geometric tolerances has produced two main measuring needs: to obtain the geometric values of industrial products with higher precision and to obtain these values in a reduced time span. In order to accomplish these objectives, one of the most investigated and applied approaches is the use of multiple sensors on a traditional coordinate measuring machine (CMM). The resulting machine is usually referred to as a hybrid CMM and it is able to combine the data from optical and contact sensors in order to produce the measurement of a specific object with higher precision and in less time with respect to the traditional CMM approach. This chapter briefly explains the hybrid CMM characteristics and the working principles of the most used sensors. Then the method for the treatment of the data acquired by the multiple sensors is presented, starting from the basic problem of data registration to the algorithm to integrate and fuse the optical and touch probe data.