We’ve seen a number of photographers who have taken to the Pi as a way to bring down the cost of the sort of kit that was, pre-Pi, outside the budgets of mere mortals. Case in point: gigapixel photography. A gigapixel image is made up of (at least) a billion pixels, which means you’ve now got access to the sort of fine and vivid detail on your monitor that we mere humans with our shonky eyeballs could only dream of until recently.
At the moment, a camera that can take a gigapixel image all in one shot is the sort of fantasy hardware that the military is pouring millions into. But if you’re not in charge of a defence silo, you can still take your own gigapixel images by stitching together many megapixel-sized images from an SLR camera on a motorised mount into a giant, seamless mosaic with very fine detail. You’ll need something approaching a defence budget if you’re going to do this yourself without building your own hardware, though; I spent a few seconds googling and found that off-the-shelf motorised rigs for your camera can cost nearly $1000.
Tim and Jack Stocker thought this was daft, so they built their own out of MDF, some Lego turntables, and a Pi with a cheap stepper motor attached.
The Pi has a lot of computation to do here: Jack’s software (which you can download on GitHub) works out the horizontal and vertical angles required, the camera sensor size, the length of zoom used and the image overlap required to stitch everything together into a tidy mosaic later on. It figures out how many photos are needed to complete the picture, when the stepper motors should be moved, and by how much and in what order; and when and for how long the shutter should be opened – it also deals with the focus.
You’ll find a long description of how to reproduce the Stockers’ setup, with a parts list, enough information for you to make your own shutter control circuit and more at GigaPi.
For obvious reasons, I can’t host a sample gigapixel image here. But you can find some pictures taken with the Stockers’ rig, one of which is a simply ridiculous 15.2 gigapixels (and enormous fun; it’s full of Easter eggs, and the detail’s so good that you can count how many peanuts are left in the bird feeder) at gigapan.com.
Bonus fact of the day: Sophie Wilson, of ARM and BBC Micro fame, is also a gigapixel photographer, and she’s created some really beautiful pictures using the technique – the architectural photos are my favourites. She occasionally gives talks in and around Cambridge on the subject, minus the Raspberry Pi (I spotted an advert for one in my local post office last week). Keep an eye out if you’re in town.