An optical flow sensor is a vision sensor capable of measuring optical flow

Optical flow

Optical flow or optic flow is the pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by the relative motion between an observer and the scene. The concept of optical flow was first studied in the 1940s and ultimately published by American psychologist James J....

 or visual motion and outputting a measurement based on optical flow. Various configurations of optical flow sensors exist. One configuration is an image sensor chip connected to a processor programmed to run an optical flow algorithm. Another configuration uses a vision chip, which is an integrated circuit having both the image sensor

Image sensor

An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras and other imaging devices...

 and the processor on the same die, allowing for a compact implementation. An example of this is a generic optical mouse sensor used in an optical mouse

Optical mouse

An optical computer mouse or "optic mouse" uses a light-emitting diode and photodiodes to detect movement relative to a surface, unlike a mechanical mouse which has a ball which rotates orthogonal shafts which drive chopper wheels for distance measurement.- Early optical mice :Early optical mice,...

. In some cases the processing circuitry may be implemented using analog or mixed-signal circuits to enable fast optical flow computation using minimal current consumption.

One area of contemporary research is the use of neuromorphic engineering techniques to implement circuits that respond to optical flow, and thus may be appropriate for use in an optical flow sensor. Such circuits may draw inspiration from biological neural circuitry that similarly responds to optical flow.

Applications

Optical flow sensors are used extensively in computer optical mice

Optical mouse

An optical computer mouse or "optic mouse" uses a light-emitting diode and photodiodes to detect movement relative to a surface, unlike a mechanical mouse which has a ball which rotates orthogonal shafts which drive chopper wheels for distance measurement.- Early optical mice :Early optical mice,...

, as the main sensing component for measuring the motion of the mouse across a surface.

Optical flow sensors are also being used in robotics

Robotics

Robotics is the branch of technology that deals with the design, construction, operation, structural disposition, manufacture and application of robots...

 applications, primarily where there is a need to measure visual motion

Optical flow

Optical flow or optic flow is the pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by the relative motion between an observer and the scene. The concept of optical flow was first studied in the 1940s and ultimately published by American psychologist James J....

 or relative motion between the robot and other objects in the vicinity of the robot. The use of optical flow sensors in unmanned aerial vehicles (UAVs)

Unmanned aerial vehicle

An unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...

, for stability and obstacle avoidance, is also an area of current research.