Rambus Fellow and Research Director Dr. David Stork recently spoke with Smithers Apex about lensless smart sensor (LSS) technology on the sidelines of the Image Sensors 2015 conference in the United Kingdom.
According to Stork, Rambus lensless smart sensors consist of special optical phase gratings affixed to standard CMOS image sensor arrays.
“Light from the scene diffracts through the grating and yields an apparently chaotic and unintelligible blob on the sensor array—appearing nothing like a familiar image in a traditional camera,” Stork told the publication.
“The grating preserves nearly all the visual information from the scene, up to the two-dimensional Nyquist limit, and thus the blob on the sensor can be processed with special algorithms to yield the final digital image.”
In short, says Stork, the grating produces an image “blob” on the sensor array that is meant for computers, rather than humans. Indeed, unlike traditional cameras, lensless smart sensors compute an image using special algorithms.
He adds, “We view the gratings less as an optical device and more as a computational device, that is, one that transforms the information from the scene into a representation on the sensor appropriate for the sensing task at hand. The grating performs its ‘computation’ in parallel, unbelievably fast (the time it takes for light to pass through the thin grating) and not merely at low electrical power, but instead at zero electrical power. Our challenge as sensor designers is to make the grating do as much of the total computation as possible, leaving the digital algorithms to finish the task.”
As Stork notes, there are a myriad of potential applications for small, flat, inexpensive sensors and imagers such as LSS. Specific examples include adding simple vision to mobile devices and appliances, toys, in the internet of things (IoT); simple human interfaces based on gestures or other visual information; biomedical sensing such as endoscopy; and automotive sensors for collision avoidance.
“Some of the best applications for our technology will be identified by others who have unique requirements [that are] hard to meet using traditional sensing methods [for] tasks such as image change detection, visual flow estimation, face detection, object tracking, people counting and so on,” he explained.
“[That being said], I’m particularly intrigued and encouraged by our most recent work on designing gratings and subsequent digital processing to address particular image sensing tasks such as image change detection, visual flow estimation, face detection, object tracking [and] people counting.”
Interested in learning more about Rambus lensless smart sensor technology? You can check out our LSS article archive here.