A Cute New Imaging Technique Named Compressive Imaging
The latest Physics News Update (see the reference above) points to very interesting new research on a new imaging technique, suitable e.g. for remote cameras. Here, light from an object is reflected from a digital micromirror device (DMD), and part of the reflected light hits a single photodiode or other photodetector. The measured light intensity is now recorded for thousands of different pseudorandom binary patterns of the micromirrors, where each mirror either reflects light or is an “off” position. A computer can later reconstruct an image from these data. Anyone being familiar with Fourier optics may immediately have at least some vague idea how that might work, but I won't try to explain this here.
The method doesn't only look cute, it is also potentially very useful. First of all, it requires only a single-pixel detector, which enormously expands the range of usable photodetectors. Second, it requires fairly little memory in the device; several thousand bytes are enough for images which hundreds of thousands of pixels, since the image information is automatically obtained in a somehow compressed form. This compression also facilitates data transmission e.g. with a wireless connection. The computational burden for reconstructing the image may not be a severe problem, since this job can be done offline. The camera itself can be very simple. Overall, the method could be very efficient compared to the traditional way of recording a full image, compressing it locally with corresponding hardware and software in the camera (using e.g. a JPEG algorithm), sending it, and decompressing it again in the computer.
This article is a posting of the Photonics Spotlight, authored by Dr. Rüdiger Paschotta. You may link to this page and cite it, because its location is permanent. See also the RP Photonics Encyclopedia.
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