Fly Eyes for Spying Cameras

Roland Piquepaille writes "Even with sophisticated cameras, we can sometimes get poor pictures. This usually happens because cameras use an average light setting to control brightness. When parts of a scene are much brighter than others, the result is that you don't catch accurately all the parts. According to National Geographic News, by mimicking how flies see, Australian researchers can now produce digital videos in which you can see every detail. This technique could be used to develop better video cameras, military target-detection systems and surveillance equipment. Read more for additional pictures and references about these future surveillance cameras."

Comments

Multi-contrast zone recording

[BadAnalogyGuy]

The problem, in short, is that digital sensors have pretty terrible contrast limitations. Film does too, to some extent, but with many years of experience these problems have been dealt with. You can only capture menaingful data within certain contrast zones. A good sensor may have 4 usable zones of contrast while your consumer digicam can probably only handle 2 and a half or three stops worth of contrast.

So what do you do? Well, since it's digital, take more pictures! expose the frame for a certain set of contrast zones and then repeatedly take the same shot with different contrast settings. Digitally combine the pics in Photoshop to render a frame with full contrast from the blackest black to the whitest white. The pictures look a little weird because we usually aren't able to see that much contrast rendered in Nature due to limitations of our eyes, but the results are pretty astounding.

Re:articles missing lots of details.

[SharpFang]

or expose multiple frames per $interval (each with a different electronic shutter length) and then composite them.. however this last technique creates smear,

That's likely what could be nicely improved with the right electronics: the smear would be at worst equal to smear of the longest exposition shot.

You'd need a shot that doesn't reset current state of exposition of the sensor between readouts. Instead of:
start, wait 1/120 s, stop, save, reset
start, wait 1/60 s, stop, save, reset
start, wait 1/30 s, stop, save, reset

but one which does:
start, wait 1/120 s, save,
wait 1/120 s (total 1/60 from start), save
wait 1/60 s (total 1/30 from start), save
stop, reset.

Still, displaying the result remains a problem. Real World is a medium of incredibly wide range of luminescences. Screen, paper, plasma TV, all have the dynamic range much smaller. You can squeeze the range of data you gathered into range of the device (and get horrible contrast), you can vary ranges of displayed areas (which creates bloom effects, looks cool, but for data processing - can't see shit, captain), extract variable info from the image (good for image processing but looks like shit for people), splice it into several images of various luminances (so why compounding it into one in the first place?) or... wait for a better display medium. Yeah, sucks.

My solution

[Bombula]

Crazy as it sounds, I solve this problem with both my film and digital cameras using an amazingly sophisticated trick called bracketing.

Seriously. With bracketing you simply take multiple shots at different exposures in quick succession. Most modern cameras with computer controls offer automated bracketing functions. And for compositing afterwards there's a nifty program called Photoshop...

Re:A tad bit off...

[Anonymous Coward]

Perhaps they should try mimick the human eye's optical nerve instead. For those billions of you out there who haven't paid attention during your lives, our optical nerve is also versatile in exposure - we don't quite suffer from the monotonous exposure syndrome that film and ccd does. We can actually adjust exposure on several separate areas of our visual. We don't need a million different eyes to do it, and we don't need to do multiple exposure passes like certain digital cameras have begun to incorporate.

It's a difference movie!

[oneiros27]

Unless there's a whole lot more going on than the article says, based on what it's talking about, and the example images, it's nothing but a difference movie.

(you look at changes from one frame to the next, and make a movie of those changes).

There's nothing new about this -- scientists have been using it for years (if not decades) for instruments that they don't have enough data to fully calibrate (eg, those on spacecraft, where they might not be able to focus on fixed targets to calibrate it in its environment). It's also useful to tell when only small portions of the image are changing, or it's changing very slightly in relation to the whole image.

Here are some examples:

• SOHO (LASCO C2/EIT)
• Vortex Dynamics in Superconductor
• TRACE