Development of a high-precision vehicle-mounted laser scanning system and study on photosensitive parameters

Pavement texture detection is an important means of evaluating road safety performance. Compared with static scanners, vehicle-mounted scanners are widely used because of their high inspection efficiency. However, two major challenges remain in practical applications: (i) a trade-off between testing speed and measurement accuracy, and (ii) limited adaptability to pavements with different brightness levels under varying illumination conditions. Under high-speed scanning, the exposure time must be shortened to maintain a small longitudinal sampling interval, which reduces the reflected laser energy captured by the camera during each profile acquisition. This problem becomes more severe for low-reflectivity dark asphalt pavements, leading to insufficient returned laser intensity, invalid profile points, and increased measurement errors. To address this issue at the data-acquisition stage, a high-precision vehicle-mounted laser scanning system (HVLS) equipped with a supplemental lighting device was developed in this study. The supplemental lighting device provides additional 405 nm illumination aligned with the built-in laser line, thereby enhancing the reflected laser signal under short-exposure conditions. This system meets the sampling requirements for macroscopic texture in the direction of travel across a wavelength range of 0.5–50 mm. It improves high-speed pavement macro-texture measurement with a longitudinal sampling interval of 0.2 mm and increases the scanning speed by up to 300% compared with the HVLS without supplemental lighting, without compromising the accuracy of MPD, Ra, and RMS measurements. Through field tests conducted on pavements with different brightness levels under varying illumination conditions, adaptive photosensitive parameters were determined, enabling HVLS to meet multi-scenario pavement texture detection requirements.