RoboRetina™ image sensor is capable of producing satisfactory images even in non-uniform illumination conditions. Existing cameras requires uniform illumination to produce satisfactory results. Photographers vary camera's shutter speed to capture brightly illuminated or poor lit scenes. Amount of light falls on the image sensor (in olden days it was film) proportional to duration of time shutter is open. Thus sun-lit scenes need short shutter opening duration. In natural light conditions both bright and shadow regions (poor lit) will be available simultaneously. But camera can be made to capture either bright region or dark region and not both. Our eyes are able to adjust to natural light or non-uniform light with ease. This feat is barely noticed by us, until this article is read.
A surveillance camera system that monitors airport will fail to detect persons lurking under the shadows because of non-uniform illumination. Intrigue Technologies Incorporation having head quarters in Pittsburgh, Pennsylvania, USA has come out with RoboRetina™ image sensor that tries to mimic our human eye. They have developed a prototype with a resolution of 320x240. This is capable of seeing things under the shadow. They have used standard CMOS fabrication process to build the prototype. The 320x240 resolution is sufficient for a robot mounted with RoboRetina to navigate on a cloudy weather. Brightness adaptation operation is carried out without the use of traditional number crunching. This feature will amuse as all, as we are conditioned to think performing digital processing only. Array of photoreceptors is called image sensor. In the prototype each photoreceptor is added with an analog circuit that is stimulated by the light and they control the functioning of photoreceptor.
Silicon based integrated chips that tries to mimic working of eye is called Neuromorphic vision sensors. The term 'neuromorphic engineering' was coined by Mr.Carver Mead in mid 1980. He was working at California Institute Technology, Pasadena, USA. Analog circuit based vision chips were developed by University of Pennsylvania, in Philadelphia, USA and Johns Hopkins University, in Baltimore, USA. Analog circuit present in the chip vary the sensitivity of the detector depending upon the light fallen on the detector. This concept only is extended in RoboRetina. Here light falls on the surrounding detectors also play a vital role in sensitivity adjustment of photo detector. Success of RoboRetina depends on the accurate estimation of illumination field.
Around 2005 itself Intregue's eye was available as an Adobe Photoshop plug-in. It was rightly named 'Shadow Illuminator'. Medical X-ray images were taken as input and software was able to reveal unclear portions of medical image. Photographers use this software to do correction in their photos which is technically called as 'Enhancement'. Software that does not use RoboRetina technique produces "halo" effect on the sharp discontinuities.
CEO of Intrigue Mr. Vladimer Brajovic is an alumnus of The Robotics Institute at Carnegie Mellon University, Pittsburgh, USA. RoboRetina got the Frost & Sullivan Technology Innovation Award for the year 2006. Frost & Sullivan [4] is a growth consulting company with more than 1000 clients all over the world. This award is a feather in the cap for Intrigue Technology. After the emergence of neuromorphic sensor concept RoboRetina is the first breakthrough. Let us hope this will lead to the Autonomous Vision System revolution which will greatly enhance the performance of automotive systems, surveillance systems and unmanned systems.
Source:
[1] Intrigue Technologies, The Vision Sensor Company, Press Release, http://www.intriguetek.com/PR_020407.htm
[2] Robotic Vision gets Sharper by Prachi Patel Predd - IEEE Spectrum March 2005 http://spectrum.ieee.org/biomedical/imaging/robotic-vision-gets-sharper
[3] Photo Courtesy: https://www.intrigueplugins.com/moreInfo.php?pID=CBB
[4] Frost & Sullivan, http://www.frost.com
Thanks:
I want to personally thank Mr. B. Shrinath for emailing me 'RoboRetina' article, that was published in spectrum online.
