Application of Blue Laser Triangulation Sensors for Displacement Measurement Through Fire
Matthew S. Hoehler, Christopher M. Smith
This paper explores using blue laser triangulation sensors to measure displacement of a target located behind or in the close proximity of natural gas diffusion flames. This application is relevant for building fire testing. Distortion of the measurement by thermal gradients around the flame is predominantly normally distributed and the soot present in natural gas flames did not noticeably diminish the signal under the investigated conditions. The position of the laser relative to the flame envelope can significantly affect the measurement scatter, but has little influence on the mean values. We observe that the measurement scatter increases linearly with the distance of the target from the flame along the beam path. Based on these observations, we demonstrate how time-averaging can be used to achieve a standard deviation of the mean value of target displacement error of less than 0.1 mm, which is typically sufficient for structural fire testing applications.