Rambus researchers are developing an ultra-small image sensor that allows to drastically reduce the cost and size of digital cameras as they will need no optical lens. David G. Stork, an optical expert who joined Rambus in 2011, has led the development of ultra-miniature sensors (0.8 x 0.8mm), which rely on special optical gratings affixed to photodetectors. The sensors enable to realize the main functions of a camera only with a CMOS sensor and signal processor.

These ultra-miniature computational imagers have no lens, have large effective depth of field (1mm to infinity), and are very inexpensive (a few Euro cents). The grating acts as a two-dimensional visual "chirp" and preserves image power throughout the Fourier plane (and hence preserves image information); the final digital image is not captured as in atraditional camera but instead computed from raw photodetector signals. This means tha the raw signals captured by the photodetectors do not resemble a traditional image in any way, but contain enough information that a final digital image can be computed in real time, using demanding signal processing algorithms.

Still, Rambus considers that there are some applications with which the advantage of eliminating optical components outweighs the disadvantage.

These sensors are so small they should find use in endoscopy, medical sensing, machine inspection, surveillance and the Internet of Things, and are so inexpensive that they should find use in distributed network applications and in a number of single-use scenarios, for instance in military theaters and hazardous natural and industrial conditions.

The details of the new technology will be announced at Trillion Sensors Summit Japan 2014, which will take place Feb 20 and 21, 2014, in Tokyo.