Utilization of Blue Ray 2D Laser CCD to Prevent Luminance Disturbance during Pavement Texture Measurement

In recent years, laser techniques have replaced the commonly used sand pitch method to measure pavement surface texture. However, the conventional red ray laser charge-coupled devices (CCDs), both the one-dimensional (1D) and two-dimensional (2D) versions, traditionally have been influenced by luminance. The study presented in this paper developed an intelligent texture measurement system (ITMS) with a blue ray 2D laser CCD instead of the red ray CCD used in previous pavement surface texture measurement research, in accordance with ISO 13473-3. In this study's light tests, a halogen lamp was adopted to simulate the light (Klux). The results indicated that the red ray 2D laser could not read the texture under lighting of more than 5 Klux while the blue ray 2D laser was minimally influenced by the light. In addition, when a 15-cm mask was used, the accuracy of the ITMS improved. Based on the presented results, the blue ray 2D laser CCD was found to be more stable than the red ray 2D laser CCD in texture measurement, and a light-protection mask (more than 15 cm) would further protect the laser from the disturbance of luminance.