Active perception is the selecting of behaviors to increase information from the flow of data those behaviors produce in a particular environment. In other words, to understand the world, we move around and explore it—sampling the world through our senses to construct an understanding of the environment on the basis of that behavior. Within the construct of active perception, interpretation of sensory data is inherently inseparable from the behaviors required to capture that data. Action and perception are tightly coupled. This has been developed most comprehensively with respect to vision where an agent changes position to improve the view of a specific object, or where an agent uses movement to perceive the environment. By a more formal definition, active perception is: The theory of optical flow derives from concepts of active perception, and while optical flow is now typically considered a vector representation of motion captured by a vision sensor, it was originally described in terms of active perception. The behavior of the agent in the world generates a flow of data over the visual sensor, which is sampled by the sensor and interpreted into a percept of the environment by the agent, through some computation. On the basis of this percept the agent selects another behavior that generates more data flow. Thus optical flow is the data flow carried by light from the environment to the vision sensor as a result of movement in the environment. A related but narrower definition of active perception represents perception and action within the brain as the same thing. It states that when a person sees an action, it internally translates into, and is understood within the context of, a possible action. This supports the capability in people and animals of learning what to do based on what they see others doing.
There is a wide range of work on the application of active perception to robotics, including ground vehicles, underwater vehicles, and air vehicles. As one would expect, when optical flow is included in the definition of active perception then the volume of related work significantly increases.
