A cost-efficient solution to true color terrestrial laser scanning
This paper presents a low-cost true color terrestrial laser scanning system, described in terms of the hardware and software elements necessary to add color capability to existing non-color laser scanners. A purpose-built camera mount allows a digital camera to be positioned coincident and collinear with the beam detector of the laser scanner device, such that mismatch between color data and laser scan points is minimized. An analytic mapping implemented in a Matlab toolbox registers the photographs, after rectification, with the laser scan point cloud, by solving for two tie-points per image. The resulting true color point clouds are accurate and easily interpretable. The adjustable camera mount fits a range of cameras and, with minor adaptation, could be used with different laser scanner devices. A detailed error analysis will allow comparisons to be drawn with alternative technologies, such as photogrammetry and commercial true color laser scanners. This low-cost, accurate, and flexible true color laser scanning technology has the potential to make a significant improvement to existing methods of spatial data acquisition.