Perception

Exteroception

Exteroception is sensing directed at the external environment, encompassing cameras, LiDAR, radar, microphones, and tactile arrays, in contrast to proprioception, which senses the robot's own internal state such as joint positions and body orientation. The distinction structures robot state estimation and policy design: exteroceptive streams are high-dimensional and semantically rich but subject to occlusion and lighting, while proprioceptive streams are low-dimensional, fast, and reliable.

Why it matters for physical AI

How policies fuse exteroception with proprioception defines their robustness envelope, exemplified by legged controllers that walk proprioceptively when vision fails but anticipate terrain when it is available.