The digital camera mega pixel race continues — 10, 20, 50, 100 megapixels? More?
According to the BBC, researchers at Rice University are developing a single pixel camera. Yup, that's a big 1 pixel, not 1 megapixel. The BBC article explains that the big advantage of the one-pixel approach is it is more efficient, requiring less processing power in the camera and therefore extending battery life. At first I couldn't work out how they made the jump from having just one pixel to a more efficient camera, but the Compressive Sensing Group at Rice University have a more detailed description (as well as references to published papers).
In current cameras a two-dimension sensor captures the image and, typically, the data from that two-dimensional array is compressed using a lossy-compression algorithm, like JPEG. Lossy means that the compression process is throwing away information that was in the captured image. Lossy compression is used so you can store more pictures on your card (and also because then you can download to your PC or email those snappy memories faster). You might ask what's the point in collecting all that image information, only to waste compute power in throwing some of it away? That's the position the Rice team have taken, and the clever bit about the single pixel camera isn't that it has a single pixel, but that someone has figured out how to sample the image by (pseudo)randomly projecting portions of it onto a single sensor in a way that means you only record the information you want to keep.
That's clever, but there's no clear indication that a more efficient capture process will lead to more efficient cameras. There's a load of computation required to reconstruct an image from the information captured by the single pixel camera. Presumably that's deemed okay because you can do that processing on the PC after you've got back from a photo excursion. Except that means no ability to preview the image on the camera. There's also the power consumption of the component that projects samples of the image onto the sensor to consider. A benefit might be sensitivity - because in theory you can make a bigger, more sensitive, single sensor than you can an array of sensors. But it's not clear how quickly the system would be able to sample the areas required to reconstruct the whole image and therefore whether a sensitive single-pixel camera would be useful for moving subjects.
Tags: digital - photography - cameras - technology - megapixels
