Combined use of photogrammetry and stripe projection for quality control of an industrial workpiece

Industrial surveying is the profiling content of the Master course. By means of a practical project which includes planning, measurement and evaluation, the subject of industrial surveying and quality control is conveyed in a realistic way.

Project task:

A workpiece is to be checked for accuracy according to a given test plan. To do this, the object must first be measured with high accuracy using a combination of single image photogrammetry (GOM TRITOP) and stripe projection (GOM ATOS). The substructure of a car seat is to be recorded (approx. 0.9 x 0.8 x 0.7 [m]). A CAD model is available for the target/actual comparison of the workpiece. The measurements are evaluated and checked in GOM ATOS or GOM Inspect.

In the first step, a network of uncoded fixed points is created on the measurement object, which is required as a frame network for the ATOS measurement that follows in the second step. This is implemented with the GOM TRITOP photogrammetry system. Coded targets, scales and target crosses are used for the photogrammetric calculation of camera positions.

With the help of the previously determined fixed point network, the workpiece itself is measured with the ATOS fixture and an area-wide point cloud of the workpiece is generated. After meshing, a 3D model is created and the elements to be inspected (e.g. holes, planes, etc.) are modelled. Subsequently, nominal-actual comparisons can be made according to the specified inspection plan (angles, distances, positions to reference elements, etc.).

The specified workpiece is checked according to the specifications of the test plan, and reports and graphics are generated. The experience gained during measurement and evaluation is discussed in a subsequent project report.