Make 3D Images with Your Own Camera
Photosynth, described by Microsoft as "the next step in the evolution of digital photography," analyses hundreds of pictures and stitches them together to create a composite image with super-high resolution. The software, released recently to the public after nearly two years of trials, lets anyone with a computer create a 3D image known as a synth using their own pictures or those from photo-sharing websites such as Flickr.
"Photosynth analyses the photographs you send it and creates a 3D world in which to present those photographs," Paul Foster, of Microsoft, said.
Unlike other photo-stitching tools, Photosynth requires no human guidance. The software package works out how the photographs fit together by recognising features within them.
"It's got some very clever image analysis algorithms in it, but basically it's looking for shape, for patterns, for texture," Mr Foster said. "It identifies those key points and then maps them across the photos to create the 3D model."
Anyone wanting to use the software must first download a free application from photosynth.com. This enables a home PC to create the 3D image and allows web browsers to view the results. Navigation tools let users view the images from a range of angles, zooming into a detail or pulling back for a wide-angle view.
The viewer uses technology from a company called Seadragon, which Microsoft bought in February 2006. This enables a web browser to display small parts of huge images without downloading the whole picture, speeding up data transfer and enabling smoother scrolling and zooming.
The playful nature of Photosynth marks a departure for Microsoft, whose corporate image is stuffier and more conservative than that of Google. The search giant has held onto much of its quirky public persona despite its huge market share and vast cash reserves, in part because of fun, engaging applications such as Google Earth and Street View.
Mr Foster parried comparisons with Google by suggesting that Photosynth was more in keeping with the community principles of web 2.0. "It's all about the community," he said. "This isn't a company that's generating stuff centrally. It's up to people to capture what they want to capture."
Photosynth looks unlikely to be an immediate money-spinner for Microsoft – the website will carry no advertising nor other commercial content – but the company does expect to find practical uses for the technology.
The London Eye has created a 3D interactive tour of the attraction, while television has hinted at darker applications. An episode of CSI New York shown in the US earlier this year used Photosynth to reconstruct a murder scene so that detectives could analyse it in detail days and weeks after the crime was committed.
Top Ten Tips for Creating Super Synths
Microsoft has put together the following advice for people working with Photosynth, based on the experiences of people who have used the trial version. Sample synths created during the trial phase can be seen on the Photosynth website.
Take lots of photos
Not all photos will connect well and picking the right ones is a matter of experience. To give you plenty of choice, take two to three times more photos than you think you‘ll need, up to a maximum of about 300, and experiment until you find the right combination.
Have lots of overlap
You should try for at least 50 per cent overlap on average between photos. This overlap makes the 3D construction possible.
Panorama first, then move around
Start by taking a panorama of your scene, then move around and take more photos from different angles and positions.
Remember the “rule of three”
Each part of the scene you‘re shooting should appear in three separate photos, taken from different locations.
Limit the angles between photos
Try to get one photo every 25 degrees or so. That will make the synth work better. Extreme angle differences on a subject won‘t match up.
Shoot scenes with lots of detail and texture
The features in the photos are what tie them together. A blank wall won‘t synth, but one with lots of art or posters will work well.
Don’t crop images
Cropping eliminates important information that Photosynth needs, or makes the focal length inaccurate.
Shoot wide shots
Wide-angle shots reconstruct more reliably than closer shots. It‘s good to have close-ups, too, but you‘ll want to have good coverage of your subject with lots of nice overlapping wide shots.
Limit post processingYou can adjust anything that won‘t drastically alter the photos (brightness, contrast, red-eye and so on). Other than that, leave it alone.
Orientation
Make sure your photos are all the right way up before you start synthing.
By Holden Frith, Times Online
