Stacey Maples, GIS Assistant, from the Map Library, demoed Photosynth, a web-based free service that takes unstructured collections of photographs (of a single object or place) and reconstructs a 3D image from sets of flat photographs. You can download Photosynth from Microsoft Live Labs.

Stace showed a small pocket map he rendered as a Photosynth by using a lazy susan, which he spray-painted black and marked off 20 degree marks for rotating the object at 20 degrees for each photograph. Using a Canon Powershot (available in CLC Media Checkout Service) he took over 200 images of the pocket globe.  Photosynth works by matching the texture and patterns in the photos and finds corresponding pixels to stitch the separate images together as a 3D object. An additional features is that Photosynth creates a point cloud thus enabling geocoding of an object. Stace found it is possible to hack the point cloud out of Photosynth and use it in open source software which means you can work with the object locally rather than on the Microsoft server. It is possible to share, embed, and send Photosynths via email.

Photosynth should work across all browers and is cross-platform. You need to install the SilverLight plugin. Stace discovered that it is faster to do video-synthing rather than with photographs. It is less laborious to and takes less time. You can go directly to a huge collection of photos via video. First, shoot panarama video then use VirtualDub create frame grabs frames. Stace was able to get 400 grabs from 90 seconds of video using a handheld video camera to create a photosynth of the Sterling Memorial Library. The ideal would be to use a high quality HD video camera with image stabilization.

The point cloud is what is really interesting, especially for archaeology. This technology could be helpful for field work excavations to record the site each day to record the progress daily. Helpful since it can be done with cheap equipment that can safely be brought into the field.

Sharing Photosynths is easy via web sites and email. You own your photos in Photosynth, Microsoft ends up owning your point cloud and the data on the running of the algorithms. They don’t own the photos even in the 3D context.

Alternatives to Photosynth - Bundler is the open source version of Photosynth. Does require some level of command-line based computing and open source software. Need to install some packages and other libraries on your computer to make this work.

Arc3D is another option from the Netherlands. Arc3D has a web server that provides processing of photo collections similar to Photosynth but with direct access to the 3D point cloud that serves as the superstructre for the photo environments in Photosynth. This software is meant to be used with fewer images, 50 rather than the 400 used in Photosynth.

For Stace Maples’ PowerPoint Presentation, please click  microsoft-photosynth

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