A vision chip is an integrated circuit having both image sensing circuitry and image processing circuitry on the same die. The image sensing circuitry may be implemented using charge-coupled devices, active pixel sensor

Active pixel sensor

An active-pixel sensor is an image sensor consisting of an integrated circuit containing an array of pixel sensors, each pixel containing a photodetector and an active amplifier. There are many types of active pixel sensors including the CMOS APS used most commonly in cell phone cameras, web...

 circuits, or any other light sensing mechanism. The image processing circuitry may be implemented using analog, digital, or mixed signal (analog and digital) circuitry. One area of research is the use of neuromorphic engineering techniques to implement processing circuits inspired by biological neural systems. The output of a vision chip is generally a partially processed image or a high level information signal revealing something about the observed scene. Although there is no standard definition of a vision chip, the processing performed may comprise anything from processing individual pixel values to performing complex image processing functions and outputting a single value or yes/no signal based on the scene.

Types of processing performed in a vision chip

There is no standard definition of what constitutes a vision chip and thus the type of circuitry that may be performed. Below is a sample list of processing steps reported in vision chip designs, as reported in several books.:

Light sensing techniques

• Active pixel sensors (APS)
• Charge coupled devices
• Logarithmic compression pixels
• Microbolometers for thermal imaging

Spatial processing techniques

• Lateral inhibition
• Artificial silicon retina circuits
• Contrast enhancement
• Edge or other static feature detection

Temporal processing techniques

• Intensity change detection
• Detection of visual motion / optical flow

Commercially available vision chips

The overwhelming majority of vision chip designs were executed largely by academic institutions as part of research projects. However several designs have, at one point or another, been commercialized as a product.

• Optical mouse sensor: The sensor chip 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,...
  
   is a vision chip.
• Mitsubishi silicon retina chip

See also

• optical flow sensor
  Optical flow sensor
  An optical flow sensor is a vision sensor capable of measuring optical flow 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...
  
  
• active pixel sensor
  Active pixel sensor
  An active-pixel sensor is an image sensor consisting of an integrated circuit containing an array of pixel sensors, each pixel containing a photodetector and an active amplifier. There are many types of active pixel sensors including the CMOS APS used most commonly in cell phone cameras, web...
  
  
• charge-coupled device
  Charge-coupled device
  A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
  
  
• neuromorphic engineering