Enter the gigapix

Gigapixel-resolution images that let scientists virtually walk the Martian surface also let you zoom into Obama’s inauguration.

Your phone camera shoots a couple of megapixels, and the latest digital camera you got last month does 10 megapixels. Would you ever need more?

Well, how about a gigapixel (Gp) - a billion pixels? What could you do with that? One of the most popular photos online in the past few weeks has been David Bergman's amazing shot of Obama's inaugural address on January 22 (Go to tinyurl.com/ht-obama with your web browser, or to gigapan.org and search for "obama"). On one site alone, the image has been viewed five million times.

What's special about it? Well, for one thing, this is a gigapixel image - nearly 1.5 Gp. Double-click anywhere, and you can zoom in all the way till faces in the crowd show up clearly (you may need to wait a few seconds while the image sharpens). You can see George Bush's bored expression, or zoom into the distant crowd and see faces clearly.

No, there is no gigapixel camera, yet. This 'super-image' was simply stitched together from 220 high-resolution photos. Bergman clamped a Gigapan Imager to the railing. That's a robotic camera mount that let him take many images and stitch them into a giant image file. The software did the stitching up automatically, taking seven hours on a Macbook. (See tinyurl.com/obama-how).

In the US, or online, you can buy a Gigapan imager even for your little point-and-shoot digital camera, for $379 (see tinyurl.com/giga09). You stick your camera into it, set it up, and it will start shooting dozens of adjacent images, which will be stitched together by the Stitcher software included.

If you want a taste of panoramas, though, you don't even need to spend that money. Many point-and-shoot digital cameras today in the ₹10k range support a panorama or photo-stitch function. You take a series of side-by-side photos, aligning them correctly (the camera guides you, so it's not difficult). The camera then stitches them together seamlessly, on the fly.

The Devil's in the Detail
So what do you do with a gigapixel image? You could of course print out massive posters, with superb detail. But put them up online using Gigapan technology, and you could do some useful things. The biggest example is Google Earth.

If you haven't tried it, just download it from earth.google.com. Zoom in anywhere on the planet, and get photos down to street level - each photo re-drawing and sharpening as you zoom in. Or simply go to Google Maps on your web browser, and click Satellite. When you zoom in, the image gradually sharpens - it's actually a fresh image that is loading, but it's all seamless.

Gigapan tech came from NASA: Its Mars rovers have used it to photograph the red planet, stitching together gigapixel images that let you see the planet from a distance, or zoom into a crater or a rock as if you were walking the planet. Gigapan is a US-based project involving NASA, Google, and Carnegie Mellon University.

The same tech can now let you photograph just about anything where you may need to see 'the big picture', but may also need to zoom into tiny details. (The Obama shot is a great security aid for Secret Service folks looking for a particular face.) Or you could have fun with panoramas. Using a 10-megapixel camera with panorama support, you could get a 40-megapixel panorama - and print posters, or just zoom in to see details in the scenery, when you get home from your travel, that you may have missed.

Or, if you feel like some weekend voyeurism, just take a 13-gigapixel image of your neighbourhood, like someone did in Harlem, New York, and spend your weekend browsing all the bedroom windows... Or just go to tinyurl.com/ht-harlem2 on your web browser!

Prasanto K Roy ( pkr@cybermedia.co.in ) is chief editor at CyberMedia, publisher of 15 specialty titles such as Voice&Data and Living Digital