Caltech professor makes 3D imaging breakthrough
The new Nanophotonic Coherent Imager (NCI) may revolutionise 3D imaging in the future.
Professor Ali Hajimiri of Caltech’s Electrical Engineering department and a team of other researchers, has created a device that radically reduces the size of the imaging sensor while simultaneously improving on the technology’s accuracy.
The new sensor allows for light intensity as well as precise distance measurements to be made from an object such that a 3D map of the object can be created.
The device uses the established LIDAR technique for range-finding using lasers, but performs it on a tiny scale where each “pixel” acts as a tiny LIDAR device. The device also employs the optical phenomena of light coherence resulting in the most accurate depth-sensing achieved to date by silicon photonics.
It is also this use of coherent light that allows the device to be reduced in size. In a Caltech news article by Jessica Stoller-Conrad, Professor Hajimiri stated, "By coupling, confining, and processing the reflected light in small pipes on a silicon chip, we were able to scale each LIDAR element down to just a couple of hundred microns in size—small enough that we can form an array of 16 of these coherent detectors on an active area of 300 microns by 300 microns”.
The research device was a small array of just 4 pixels by 4 pixels, but it is envisaged that this will be significantly increased for real world applications. Professor Hajimiri already foresees a large amount of applications for the technology, and the low cost of this technology should see it become a reality.
The associated images of the coin shown here were stitched together using multiple data captures from the 16 pixel sensor looking straight down on the coin. Once the final image is tilted you can see the way the 3D data was captured in peaks and troughs. Quite impressive for an early stage sensor, especially when you consider the imaging was done at half a meter distance from the coin.