Oxford: New pixel design offers high dynamic range at low cost

Licensing opportunity

Researchers at Oxford University have developed an image pixel design with a high dynamic range and improved performance in low light intensity for use in sensors in automotive, industrial, security and consumer products.

The market for electronic imaging in devices including digital cameras, mobile telephones, computers and other sensors has spurred the development of single chip CMOS cameras.

The vast majority of these cameras create an image by integrating the photocurrent within each pixel for a predetermined period. This creates a voltage that is proportional to the photon flux at the corresponding pixel, a simple imaging strategy that achieves a large enough dynamic range for scenes with relatively uniform levels of illumination.

However, many scenes have much wider dynamic range, and as a result scenes are either underexposed in the darker areas, overexposed in brighter areas, or both. This is a particular problem for surveillance systems and may create a safety hazard in automotive applications.

The Oxford pixel design uses a logarithmic response to increase the dynamic range of imaging sensors. The new design also has improved performance in low light. The pixel design is similar to a conventional integrating pixel, but with a wide dynamic range and improved low light sensitivity. It can be controlled by the user to create either a true logarithmic response, or a response equivalent to a global tone-mapping generator.

The pixel is also easy to describe mathematically, which means that it is simple to determine the reference voltage that will create a particular pixel response. As a result, the design offers a better quality and more information from any image.

While it will suit low-cost mass market applications, it is also appropriate for more demanding applications, such as automotive sensors.

This work is the subject of a patent application and Isis, Oxford University’s technology transfer office, would like to talk to companies interested in developing commercial opportunities.

For more information, visit the project’s page at: http://www.isis-innovation.com/licensing/6614.html