Photosynth: build interactive 3D environments from multiple 2D images

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Microsoft Photosynth is a program that can combine multiple images taken at or around a single location from multiple perspectives into a single, unified whole. The resulting synth can be viewed as a single object from different perspectives and browsed in and out of, and it incorporates many of the details that might have been contained in the various source images.

Microsoft’s Photosynth technology is based on the premise that different images of the same place – even images that are taken by different people and uploaded all over the internet – can be combined automatically such that they ultimately provide a simulated 3D environment (see the video at the bottom of this post).

This review, however, will focus on the recently released Photosynth desktop client that can be used by individual users to process their own images.

To understand what this program does consider the following example: imagine that you are at a gallery or a museum looking at a massive wall-size painting from across the room. At that vantage point the entire painting is visible as a single image, but as you step closer to the painting from the left, that side of the painting becomes more prominent as its right-hand side recedes into the distance. As you get nearer to it, you start to notice the deliberately rough texture of the surface of the painting, something which was not apparent from your initial vantage point. Stepping even closer, you can now see detail sections of the painting but not the image in its entirety; however individual brush strokes and scratches on the surface of the painting are now visible, and you can see surfaces where the paint is cracking, as well as, say, any random materials (paper, cloth, sand) that the artist might have applied to the surface, etc.

A simple digital image, of course, will not capture the above experience no matter how high it’s resolution may be. What Microsoft Photosynth can do, however, is consolidate a few dozen (or a few hundred) snapshots of the painting that are taken from various distances and points of view into a complete whole. The more information you give it (i.e. images taken from different angles and distances, closer-ups that clearly show the surface texture, etc) the more Photosynth is able to generate a browsable “synth” that approximates the experience described above. Here are more notes on this program:

  • How to install: you will have to download and install the Photosynth software and log in using a Hotmail or Windows Live ID (if you don’t have one you will have to get one). You will then have to create a Photosynth login name. Note that this is an online service, and that (a) you can upload up to 20 gigs (yes, gigabytes) worth of images into your Photosynth account, Several stills taken while browsing a synthand (b) any Photosynths created are public and can be viewed/browsed by all users.
  • How to use: take a lot of pictures, then upload them. That’s it; however before uploading make sure that all pictures are correctly rotated (i.e. no upside down pics). You can manipulate your pictures prior to uploading (say, for color correction) but do not crop them.
  • Tips for taking pics: start with the corners of the room and work your away around, snapping every detail. Go around objects (e.g. tables) and snap away, getting as much info as possible. Focus your efforts on textures and contrasts, not, say expanses of walls where nothing much is happening. (These tips are taken from the “How to Synth” video which can be found here).
  • Photosynth in action: it will take a few minutes for your “synth” to be built, depending on how much data you are uploading. Typically not all of the uploaded images can be used in a 3D construct, and the program will let you know the percentage of images that it could use to create a synth (will say something like “75% synthy” at the end of the Photosynth process).
  • Viewing Photosynths: you will need to install (a) a Photosynth browser plugin, and (b) the Photosynth local app. Firefox and IE are both supported.
  • Contols: you can browse synths using a multitude of controls, including on-screen clickable arrows, the arrow keys, the mouse scroll wheel and the mouse (left click and move the mouse to simulate arrow keys). Hovering over the synth will display rectangles denoting individual stills that you can zoom into. Pressing the left mouse button for a long time will display a “disc” that can be used to rotate your view by 360°. Other contorls can be accessed using the icons on the top right of a synth.

Wish list:

  • Not sure why you need to install Photosynth locally to view synths online; seems like a browser plugin should have been sufficient. Seems like the. Also I would love to be able to embedd a synths such that it is freely viewable inside a web page.

The verdit: this is proof positive that Microsoft does create cool things. What’s great about this program is the ease that of creating these things; all the user has to do is snap pictures and upload; there are absolutely ZERO decisions that have to be taken on the user’s part.

I experimented with building a synth of one of my own paintings, pictured in the screenshot above (you can see it here, but will have to install Photosynth first). I uploaded 37 pictures totalling 45 megabytes; the results were good but not as good as I had hoped; however I am sure that with more data (more pictures focusing on textured areas) the results would be better.

From a practical point of view, imagine the applications this could have in terms of, say, creating synths for products sold on sites like Amazon or eBay, etc. As far as this is concerned I really hope that Microsoft will offer embeddable synths or a simple synth viewer that can be inserted into any web page freely.

Check out the following video that described Photosynth technology:

Version Tested: 2.0.1403.5

Compatibility: Windows XP sp2 or sp3 or Vista. Internet Explorer browser or Firefox (v. 2.0 or 3.0) required. 32 MB graphics card minimum set to full graphics acceleration. Runs on some DirectX6 capable cards and all DirectX7 cards.

Go to the Photosynth Home Page to download the latest version (approx 8.17 megs).