Portable Crack Measurement Vision System Based on Parallel Laser

Crack measurement technology has important application requirements in highway bridges protection, cultural relic protection, and industrial production etc. But many target cannot be directly touched and measured. And most of the existing measuring tools are big. A portable crack width measurement system based on parallel laser is proposed in this paper. A parallel laser is designed as the measurement datum, and the intelligent cellphone is used as computing platform. Comparing with the traditional vision measurement method, it does not need the camera's internal parameters and the measuring distance, and it does not communicate with the cellphone except for take photos. So it can be used with any smartphone conveniently. The experiment shows that this system can be used as high accuracy portable non-contact measurement tool.