Range sensors are devices that capture the three-dimensional (3-D ) structure of the world from the viewpoint of the sensor, usually measuring the depth to the nearest surfaces. These measurements could be at a single point, across a scanning plane, or a full image with depth measurements at every point. The benefits of this range data is that a robot can be relatively certain where the real world is, relative to the sensor, thus allowing the robot to more reliably find navigable routes, avoid obstacles, grasp objects, act on industrial parts, etc. This chapter introduces the main representations for range data (point sets, triangulated surfaces, voxels), the main methods for extracting usable features from the range data (planes, lines, triangulated surfaces), the main sensors for acquiring it (Sect. 31.1 – stereo and laser triangulation and ranging systems), how multiple observations of the scene, for example, as if from a moving robot, can be registered (Sect. 31.3) and several indoor and outdoor robot applications where range data greatly simplifies the task (Sect. 31.4). |
