The author presents an optoelectronic system called CREHOS: a high-speed, high-resolution, and large-area laser scanner for the fully automated detection of narrow cracks in large rough surfaces. The main application is the survey of road pavements (a 4-m-wide lane at 80 km/h, 1 x 2-mm resolution). The system includes two original elements: a large multifacet holographic light collector and a custom parallel processor for real-time recognition of cracks. A prototype has been built. The author presents the general concept of CREHOS, the principle of the holographic collector, and the robot that has been built to record this special hologram. The electronic device is also sketched.
Max Monti, Max Monti,
"Large-area laser scanner with holographic detector optics for real-time recognition of cracks in road surfaces," Optical Engineering 34(7), (1 July 1995). https://doi.org/10.1117/12.204793