In-situ fringe projection using coherent image fibers

Fast in-situ inspection of functional geometries, such as tools, is an essential task in many production processes. Increasing integration of machinery results in a limited accessibility for measuring systems. To enable the detection of geometry deviations under these conditions, an optical measuring system based on the fringe projection principle is in development. Compact dimensions and versatile positioning of the system’s sensor head are achieved by using gradient index lenses and flexible image fibers, which are connected to a base unit containing the pattern generator and camera sensor. This contribution gives an overview over the optical design of the new system with a focus on the imaging artifacts emerging from the fibers and gradient lenses, followed by a description of the adapted image processing, calibration and reconstruction algorithms for fringe projection profilometry. Measurements of calibrated reference geometries and industrial forming tools are shown to demonstrate the capabilities of the new system.