A Lightweight and Cost-Effective 3D Omnidirectional Depth Sensor Based on Laser Triangulation

In this paper, we propose a new lightweight and cost-effective 3D omnidirectional depth sensor based on laser triangulation in order to ensure a wide field of view (FOV) while achieving portability and affordability. The proposed sensor is tiny palm-sized and hence easily installed even on small moving objects, which is largely composed of a structured light-based 2D sensor and a rotating motor for creating a full 360 degree horizontal FOV, thus providing a 3D omnidirectional sensing capability. The structured light-based 2D sensor is specially designed to maximize the vertical FOV by employing a fisheye camera and a laser beam passing through two cylindrical lenses for projecting a line onto a surface. From the rotational movement of the 2D sensor due to the mounted motor, its surroundings are scanned by extracting the corresponding 3D omnidirectional depth information from laser triangulation. The actual implementation is carried out to examine the technical feasibility of realizing the proposed 3D omnidirectioanl depth sensor. It turns out that the proposed depth sensor covers over 97 % area of its surrounding sphere. It is also observed through experiments that the proposed 3D omnidirectional depth sensor has similar accuracy to that of a Velodyne HDL-32, 32-channel light detection and ranging (LIDAR) sensor, at a range of $5~m$ to $6~m$ while providing much wider vertical FOV and higher vertical resolution.