2008年8月27日 星期三

From Snapshots, a 3-D View

State of the Art

From Snapshots, a 3-D View

Stuart Goldenberg

Published: August 21, 2008

How do you describe a place? How do you express its essence to people who aren’t there?

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Photosynth technology from Microsoft turns Parthenon photos into a three-dimensional world.

You use the best technology you have available.

In the beginning, there was the printed word (“Dear Queen Isabella: You gotta see this place!”). Then there was audio (“My God, it’s full of stars!”). Eventually, photos (“That’s us in Hawaii. Or is it Cape Cod?”).

Wednesday, Microsoft introduced yet another way to represent a place: Photosynth. This sophisticated technology does a simple thing. It turns a bunch of overlapping photos into a 3-D panorama.

The result, called a photosynth, is a little bit like a virtual world. You can move sideways, up or down into neighboring photos. You can turn around to look behind you. And at any time, you can zoom forward incredibly far into a photo, since it retains all of its original, multi-megapixel resolution.

Creating a photosynth is free and automatic. You visit www.photosynth.com, click to install the necessary Web browser plug-in, and start uploading your photos. (You need a Windows PC and either Internet Explorer or Firefox 3. A Mac version is under development.)

Photosynth is brought to you by a 15-person team at Microsoft Research, a division of Microsoft whose projects aren’t expected to generate income. This team hopes that the popularity of Photosynth will explode and that it will actually become a new medium. In fact, someday Microsoft hopes to design a way to connect these photosynths, eventually building a complete photographic, navigable, digital version of our real world.

In the meantime, Photosynth is a great way to visit a place before you go there, to remember a place after you’ve been there, or to show your inner sanctum to the whole world.

It’s also great for museums, galleries and anyplace else where extremely close-up inspection by the masses would be desirable, but not otherwise practical. And it doesn’t take much imagination to see how Photosynth might appeal to real-estate agents.

In a Photosynth demonstration at the annual TED conference last year, the presenter blew the crowd’s mind with a photosynth of the Notre Dame cathedral in Paris, made up of photos mined from Flickr.com. In other words, Microsoft had created a seamless, successful photosynth using hundreds of existing photos, taken by different people at different times using all kinds of cameras.

That, frankly, is a far more amazing prospect than what Photosynth is today. If using existing Web photos were an option, you could have a substantial amount of the world photosynthed already.

But for technical and legal reasons, Microsoft has backed away from that approach. Now you have to take the pictures yourself, expressly for the purpose of photosynthing.

You have to take lots and lots of overlapping pictures. Ideally, every inch of the room or space should be included in at least three photos. You stand at each corner of the room and sweep the interior, snapping away; then repeat while standing against the wall. Stand on chairs, walk to a new spot, walk up close to interesting objects.

Eventually, your photosynth is given a “synthiness” score, meaning the degree of recognizable overlap. The synthiness determines how seamlessly your 3-D panorama flows from view to view.

You can also walk completely around a stationary object, taking at least 24 photos during your circumnavigation. Later, you can rotate that object online using a doughnut-shaped scroll bar.

Once you’ve transferred the photos to your PC, you sign in to Photosynth; bizarrely, you need both a Microsoft Passport account and a Photosynth account, both free. Then you click the Create Photosynth button. Technically, your PC, not the Web site, does the analysis to knit all of those photos together, so the speed of the analysis-and-uploading process depends on your computer’s horsepower.

When it’s all over, your photosynth is live on the Web, visible for all to see. (In this version, you can’t create private photosynths.)

Amazingly, the software figures out how your photos relate, even though they’re taken at different angles, zoom amounts, exposures and so on.

It’s also amazing how, when you’re exploring the resulting photosynth, the full resolution of the original photos is available. You can zoom in, and in, and in, revealing more and more detail along the way, without ever waiting for even the biggest photo files to “load.” In one example on the Photosynth site, you start in the marbled gallery of the National Archives building in Washington — and you can zoom all the way in to the words “We the People” on the Constitution in its display case.

(This is one crucial difference between Photosynth and Apple’s QuickTime VR, which has been around for years. You can zoom in slightly in a QuickTime scene, but you can’t fly nearly infinitely into one of the component photos. Other differences: Making a QuickTime VR scene requires a special, 360-degree tripod apparatus and commercial software. And a QuickTime VR scene is rooted to one spot; you can’t freely walk through a space, as you can with Photosynth.)

So yes, it’s amazing. But in its current version (“call it beta, call it 1.0, call it whatever you want,” as the Web site puts it), Photosynth is also very frustrating.

First, synthing takes practice and patience. There’s no easy way to track whether you’ve taken enough photos to cover your space. You don’t know that you’ve failed until you’ve uploaded all the pictures and discovered blank spots or clumps of detached photos.

It’s also incredibly frustrating to navigate a photosynth. There are three ways to move around in your 3-D space: the mouse, the arrow keys or the letter keys. But what you press may not be what you get. If you press the up-arrow key, hoping to look upward, you may suddenly be teleported to a totally different part of the room. That can happen, Microsoft explains, if that other photo is the only one showing a patch of ceiling. Well, fine, but it’s totally disorienting.

At other times, you might want to scroll onto an adjoining photo — but all you get is black space and a bunch of white, dusty pixels known as the “point cloud.” That’s because Microsoft has decided that once you’ve magnified a photo enough to fill the screen, you can’t scroll to any other photo until you zoom back out. Frustrating.

These annoyances add up to the most frustrating thing of all: Photosynth’s photo-centric nature. I’ve probably made it sound like a photosynth gives you a seamless virtual environment, but it’s really not that; the component photos very much retain their “photoness.” You see their outlines flicker into view as you move your mouse around a scene. When you scroll between photos, Photosynth makes no effort to make them appear as a single image; one just fades into the next.

Finally, only one photo is ever in sharp focus at a time; neighboring photos are blurred and dimmed, which destroys the illusion of being in a virtual space.

In other words, Microsoft has designed Photosynth to be less a virtual-reality tool than a glorified slideshow, a clever way to arrange a bunch of discrete photos in space. That’s fine, but it does make photosynths less magical than they could be. Compare Photosynth’s one-photo-at-a-time focus with, say, the seamless views of a QuickTime VR scene (Google “QuickTime VR gallery” to see some), where everything is in focus as you look up, down, left, right, forward or back, as if you’re inside a giant wraparound photo.

Even so, Photosynth is wicked cool, and it will find all kinds of new uses. At the very least, it represents another milestone in the evolution of place-description technologies. Until someone comes up with brain-to-brain image sharing, that will have to do.


軟(Microsoft)有點像是科技領域的通用汽車(General Motors)。當然﹐這個軟件巨頭無論是在財務狀況還是市場份額上都要比那個陷入困境的汽車製造商成功得多。不過﹐和通用汽車一樣﹐微軟的規模──員工人數已逾9萬──及其官僚體系常常讓這家公司看上去比規模較小的競爭對手谷歌(Google)和蘋果公司(Apple)更加遲鈍﹐更缺乏創新。

由於微軟的Windows Vista操作系統獲得的評論不及蘋果的Leopard平台熱烈﹐其Live Web互聯網搜索服務和谷歌的差距也不斷加大﹐近年來﹐創新性上的對比越來越鮮明。此外﹐與蘋果光滑的iPhone和谷歌即將推出的手機操作系統Android相比﹐微軟的手機軟件Windows Mobile看起來要老笨些。

不過在微軟位於華盛頓州雷德蒙德的大片園區裡﹐確實存在著創新。舉例來講﹐去年Microsoft Office進行了大膽、激進的重新設計﹐無論是在口碑方面還是商業上都大獲成功。

現在﹐微軟內部有個專門開發創新產品的“游擊隊”﹐其任務就是更快地設計出更多創新產品。該部門名為Live Labs﹐它致力於更快地把科技理論轉化成現實的、基於Web的產品。這個小組只有約125個人﹐而且還進一步分成了研究不同具體項目的若干小組。

本週﹐微軟的Live Labs將推出首個面向大眾消費者的Web服務──Photosynth。這項服務能將一個場面或是場所──比如一個畫廊或是一座建築物──的多張照片轉換成三維場景﹐讓你在Web上能有置身其中之感。






安裝了一個小插件後﹐你就可以在網絡瀏覽器中使用Photosynth了。目前﹐它只能在Windows操作系統下運行﹐可用的瀏覽器只有微軟的Internet Explorer及其競爭對手的Firefox。用於蘋果電腦的版本還在研發之中﹐目前在蘋果操作系統中你甚至無法看到其他人製作的synth。





Walter S. Mossberg