Rice Professors Developing Single-Pixel Digital Camera
by: Laurie Johnson, October 2, 2006 12:10:00 am
A standard digital camera has millions of pixels, which make up the tiny colored dots that compose a picture. Rice University Assistant Professor Kevin Kelly says all of those pixels end up being compressed into a much smaller file. So he and a colleague decided to invent a camera that would eliminate the compression process while still producing a high-resolution image.
"Normally, digital cameras, of course, are composed you know of four or five or six megapixels and that tells you how good of resolution of an image you're going to capture. What we're working on here is a single pixel camera because what your camera is really doing when it records six megapixels is it's really throwing away like 90 or 99 percent of those when it stores it."
Instead of capturing a million points of light like a regular digital camera, this camera captures one point of light thousands of times in succession. Rice University Professor Richard Baraniuk says a grid of bacterium-sized mirrors are used to turn light into electrical signals.
"The camera looks just like a regular camera -- digital or film camera -- the big difference is that we replace the film with a detector array with a set of mirrors that are throwing light in a randomized fashion and then we're collecting that light at the single pixel photo detector."
Don't expect to see a single-pixel camera on the consumer market any time soon. Megapixel cameras are small, cheap and easy to use so there's no real need to alter the technology. But Baraniuk says this camera could be used to capture images on wavelengths outside the visible spectrum.
"There's a lot of applications in say the infrared wavelengths or terahertz wavelengths where there's really two fundamental problems. The first is physical size. You can't make those detectors small enough in order to miniaturize like you can in a digital camera. And the second is cost. These can be tens or even hundreds of dollars or more per sensor and so imagine trying to build an array of a million detector, each of which costs a hundred dollars. That would be a very expensive camera.
Things like security screening devices, cat scans and satellite cameras could be developed using single-pixel technology. It's all still new and in development, so it takes a long time to collect the image, as much as five minutes depending on the resolution. But the technology will improve and get to the point where it takes well under a second to take the snapshot.
"And I think the thing to compare against is that the world's first photograph ever taken took eight hours to acquire. So we're already well under the world's first photograph taken with a conventional film camera."
Laurie Johnson, Houston Public Radio News.