Scientists develop lensless photography system
posted Tuesday, June 4, 2013 at 11:31 AM EDT
A new breakthrough from Bell Labs has created a lensless photography system based on off-the-shelf parts, that can assemble an image out of far less data than most cameras. While it's not going to unseat traditional photography, this lensless camera opens up some intriguing possibilities for the future of imaging.
While most cameras use lenses to capture the light for recording images, lensless systems are not exactly revolutionary. After all, a pinhole camera is technically a lensless photography system. But this new set-up from Bell Labs uses "compressive sensing" to put together an image in a way wholly novel from most digital cameras.
The rig is essentially two parts: a controllable array of small apertures, in this case an LCD panel, and a single pixel sensor. It was assembled from cheap, readily available components. The system works because much of the information recorded by a traditional camera is highly redundant, and this attempts to account for that by creating the image using the least possible amount of data.
To function, a random array of the apertures are opened, and the sensor records the image. This happens again and again, and the data is analyzed, and used to create the photograph. While the resolution (at least for now) is very low, and it requires countless iterations to work (making it very slow). But there are some very interesting advantages. For one, it has an infinite depth of field, and doesn't suffer from optical aberrations from the lens. It was also assembled from common hardware, can be used for other wavelengths of light, and can be tied to multiple sensors for multiple views of the same scene.
For an example of how efficient the system is, the prototype device was made using a 302x217 LCD. For a perfect representation of the image, each of the 65534 squares in the LCD would have to be sampled from, requiring 65,534 different exposures. However, the image of the books (below) was taken using 16384 measurements, just 25% of the maximum. Not exactly practical for day to day shooting, but nonetheless very interesting.
If you want to read more of the research behind this new system, the paper for it is freely available at arXiv.