Three-Dimensional Visual Reconstruction of Path Shape Using a Cart with a Laser Scanner

A movable three-dimensional measurement system of the shape of a path (road) surface has been developed. The measurement can be taken by rolling the proposed measurement cart along the path. The measurement system is composed of a laser scanner, CCD camera, omni-directional camera and a computer. The laser scanner measures the cross-sectional shape of the path at a rate of 40 Hz. The direction of the CCD view is downward to observe the texture of the path surface. The relative movement of the measurement cart to the path is detected by analysing the optical flow of the texture movement. Crosssectional shapes of the path are accumulated, and the three-dimensional path shape is reconstructed on the basis of the movement of the measurement cart. The image data recorded by the omni-directional camera are allocated to the three-dimensional shape data, and the three-dimensional path is visualized in color on the computer. The reconstructed path data can be used for repair and design of a path in the field of civil engineering. The experimental results show the feasibility of our system.