MEASUREMENT 22 VSET Measuring. Measurement of raw-part geometry by Photogrammetry technology The measurement module mainly consists of a set of optical mar- kers and calibrated bars, a self-calibrating digital photogrammetry camera and a laptop, all presented in trolleys and safety cases that are easily used in these industrial environments. Photogrammetry is a technique for calculating the 3D coordi- nates of a number of points of an object. Several photographs of an object are obtained from different camera positions and/or orientations. By identification of corresponding points at different images by artificial vision it is then possible to calculate both the positions and orientations of the camera for each of the images and the coordinates of the points identified. Figure 3. Photogrammetric measurement: optical markers, reference crosshead and reference bars. An in-process computing strategy was developed for solving the photogrammetric adjustment, divided in two main steps: first, computation of an initial approach for camera location and orien- tations (so called extrinsic parameters) and marked point 3D coordinates, and second, final computation of the complete photo- grammetric adjustment. A reference crosshead (Figure 3) with coded markers with known coordinates is used as the input data for the initial approach, ser- ving for two purposes: determining the reference frame for solving the photogrammetric adjustment, and providing a first scaling reference for the scene. For measuring some specific points of the part, the most relevant methods are the laser tracker and photogrammetry Raw part automatic fitting algorithm The best module is a software development related to the measu- rement module, which based on optimisation algorithms almost immediately carries out the 3D best fit calculations of the finished workpiece, comparing it with the scatter plot that defines the raw workpiece. VSET Fitting module allows the user to match a point cloud to from a raw piece to an ideal CAD model. It also allows the user to set points with specific overstock needs that the algorithm will try to comply. To allow the usage of this fitting afterwards, the soft- ware is able to show different flags in the 3D view. The software can calculate and show distances between selected points. It can also calculate fitting circles to selected points and show that information. Additionally, the software enables the creation of reports of this measurement and best fit is a references’ report that will make it possible to carry out the alignment in the machine in a simple manner by means of set-up procedures that are usually already integrated in the machine. Figure 4 shows a schematic view of a raw part characterization result by photogrammetry given by the 3D coordinates of the markers located on the surfaces to be machined. In machine integration After the virtual alignment is obtained with adequate overstock distribution in all surfaces to be machined, the location of the raw part is verified by the use of the due and actual location of some of the optical targets.This software module allows the automatic integration of fitting results into the machine control and, through calculation algorithms, makes it possible to carry out an automa- ted, guided alignment process, facilitating and further reducing the time of this work.