If you read yesterday’s post about the inner workings of the CCD, you’ll know that the camera sensors store images in an analog form. The subsequent amplification and conversion to digital introduces all sorts of noise, and is one of the reasons big chips are expensive, and why sensors in general don’t usually do well in low light.

But did you know that a memory chip, the kind found in any modern-day electronic device, is actually very sensitive to light? Pop one open and as the photons stream in, they kick up a particular storm and excite the electrons inside.

These two facts are behind the invention of the Gigavision by Edoardo Charbon and his team at the Technical University of Delft, Netherlands. They discovered that if you actually focus light on a memory chip, each cell therein will store a charge proportional to the amount of light that hits it.

Why is this exciting? Because that data is already digital. What memory chips do, after all, is store digital information and send it quickly to the computer ’s brain. And because the data doesn’t need to be converted to be used, the number of components needed at each photo-site falls dramatically. In fact, the chips will be two orders of magnitude smaller. This means that, where only one pixel would fit before, 100 pixels can now take its place.

There are drawbacks. While these chips would be as cheap to produce, there are technical problems. First, the tiny pixels are not very sensitive to light — the bigger the pixel, the more light it can gather. Second, because these are digital pixels, they store a 1 or a 0. This means black or white, with no grayscale. Charbon is currently using oversampling to average a gray value from arrays of 100 pixels. As it turns out, this works pretty well.

“It’s turning out to be a lot more accurate than the greyscale values you get from regular CMOS sensors,” Martin Vetterli, a member of Charbon’s team, told New Scientist. “Analog-to-digital conversion gives only poor estimates of the actual analog light value.” Low-light and highlight performance is also better than that of current technology.

And while we won’t be seeing 100-megapixel cellphones anytime soon, Vetterli says that the team should have a large-scale chip by the end of the year, and could be snapping pictures with it early in 2010.

Cheap Naked Chips Snap a Perfect Picture [New Scientist]

Photo: jurvetson/Flickr