System design for anti-interference of smoke in metal liquid level detecting

In order to eliminate the smoke noise in metal liquid level laser detecting for cast machine, a new system is integrated with semiconductor laser, optical lens, Charge-Coupled Device (CCD), high speed analog signal processor, Field Programmable Gate Array (FPGA). It is based on the theory of triangulation method and the idea of real time surface compensation. The location of the scattering spot will change with the change of metal liquid level, so the level can be calculated by the relationship between the location of the scattering spot and the metal liquid level. However, smoke will influence the location of spot. This system can improve the received light intensity by adjusting the light integration time, and as a result eliminate the interference of smoke, improve the displacement measuring accuracy in smoke environment.