A depth camera is a sensor that captures per-pixel distance information alongside a conventional intensity image, producing a registered RGB-D data stream or raw point cloud. In robotics, depth cameras are used for 3D scene reconstruction, obstacle avoidance, object recognition, and SLAM. Common operating principles include structured light projection (e.g. Intel RealSense), time-of-flight measurement, and stereo triangulation; each involves different trade-offs in range, resolution, and outdoor usability.