a b s t r a c tDimensional inspection tasks are often carried out on conventional coordinate measuring machines (CMMs). These CMMs can differ in layout and size depending on the application area. They can have measurement volumes up to 100 m 3 . However, when measuring large objects it is not always possible to bring a large object to these conventional CMMs. That is why for these applications mobile measuring systems are an ideal solution. These systems often measure the dimensions through optical techniques, like interferometry and optical triangulation. After a short survey of common optical measurement techniques for mobile and large-scale measurements, this paper focuses on two industrial cases where different techniques were used to solve a measurement problem. The first case covers the measurement of a large iron casting with an optical LED-based triangulation system. It was possible to predict problems that would occur with the machining of the part, like unfinished surfaces after milling due to material shortage, and adapt the alignment of the part to prevent these problems. The second case covers the measurement of a double-decker train by means of photogrammetry, as an alternative for the currently used total station. Despite some specific drawbacks of photogrammetry systems it was possible to obtain the same accuracy and to reduce the overall inspection time significantly in comparison with the current situation.

a b s t r a c tThis paper presents a performance evaluation test for laser line scanners on 3D coordinate measuring machines (CMMs). Laser line scanners are becoming more popular in recent years, mainly for free form inspection tasks and reverse engineering. Error specification of these scanners is difficult because of many influencing factors like surface quality, surface orientation and scan depth. Therefore, procedures for evaluation and verification of conventional contact probes (e.g. touch-trigger probes) are not appropriate for non-contact laser line scanners. A straightforward test method that uses a planar test artefact is proposed. It enables to identify the influence of in-plane and out-of-plane angle, as well as scan depth on systematic and random errors of the laser scanner. Experimental results show that the tested commercial laser scanner, after calibration, exhibits systematic errors of about 10 mm.

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