# Rebuilding the world one pixel at a time

##### January 10, 2011 By Miles O' Brien and Jon Baime

Who says Rome wasn't built in a day? With the muscle of about 500 computers and 150,000 still images, Steve Seitz, a professor in the Department of Computer Science and Engineering at the University of Washington's Seattle campus, and his colleagues have reconstructed many of Rome's famous landmarks in just 21 hours.

"The idea behind "Rome in a Day"' is that we wanted to see how big of a city or model we could build from photos on the internet," says Steve Seitz from the university's and imaging laboratory. With support from the National Science Foundation (NSF), they're rebuilding Rome by pixel rather than brick by brick.

Calculations that once took months now take hours. "This is the largest 3-D reconstruction that anyone has ever tried," explains Seitz. "It's completely organic; it works just from any image set."

The project starts with a trip to the photo-sharing site Flickr to search for images of the real thing. Once pictures are identified, the computer starts the process of making 3-D objects from 2-D stills. Sameer Agarwal, a former postdoctoral scholar, at the university is mostly responsible for creating the that makes 3-D objects in from thousands of 2-D images.

"If I am a sculpture and there were three photographs of me, we would try to find three points in each that point to my nose. From that we know that there are three points in these images that correspond to a single point in the 3-D world," explains Agarwal. "We would be able to say where in a particular image corresponding to that camera, the image of my nose should show up. This statement can be written as an equation involving the position and orientation of the camera, the position of my nose and where in the image my nose shows up. And you can connect all of these equations together and solve them to, in one shot, obtain both the positions of the cameras as well as the position of my nose in the 3-D world relative to those cameras."

Computers map huge clusters of points in 3-D space creating ghost-like images called "Point Clouds."

Seitz says the imaging is very accurate. "For the buildings, I think we can get accuracy to within a few centimeters. We've measured this. For individual objects that are photographed closer, we can potentially do a lot better, like millimeter accuracy."

Finally, color and texture are added. What Seitz and his colleagues have gotten are virtual 3-D tours of cities like Dubrovnik, Croatia or Venice, Italy.

"What excites me is the ability to capture the real world; to be able to reconstruct the experience of being somewhere without actually being there," says Seitz.

In the future this "next generation" technology may show up in places online like mapping sites, video games or real estate sites--it's a virtual guarantee.

## Related Stories

#### Rome was built in a day, with hundreds of thousands of digital photos

September 15, 2009

(PhysOrg.com) -- The ancient city of Rome was not built in a day. It took nearly a decade to build the Colosseum, and almost a century to construct St. Peter's Basilica. But now the city, including these landmarks, can be ...

#### Worth a thousand million words: Researchers create 3-D models from online photo databases (w/ Video)

November 23, 2010

Who says Rome wasn't built in a day? Computer scientists have invented a technique that automatically creates 3-D models of landmarks and geographical locations, using ordinary two-dimensional pictures available through Internet ...

#### A 360 degree camera that sees in 3D (w/ Video)

December 1, 2010

Surround sight has come to the camera. Inspired by the eye of a fly, EPFL scientists have invented a camera that can take pictures and film in 360° and reconstruct the images in 3D.

#### Researchers Teach Computers to Search for Photos Based on Their Contents

October 8, 2008

A pair of Penn State researchers has developed a statistical approach, called Automatic Linguistic Indexing of Pictures in Real-Time (ALIPR), that one day could make it easier to search the Internet for photographs. The public ...

#### Patients find computer imaging before rhinoplasty moderately accurate, useful

November 15, 2010

Computer imaging to predict how patients will look following plastic surgery involving the nose appears to be moderately accurate, and patients value its inclusion in the preoperative consultation, according to a report in ...

#### New technology could make TV more exciting

February 2, 2005

Live TV outside broadcasts that combine real action and computer-generated images could become possible for the first time, thanks to camera navigation technology now under development. The work is opening up the prospect ...

## Recommended for you

#### Energy from electric cars could power our lives—but only if we improve the system

November 22, 2017

Power stored in electric cars could be sent back to the grid - thereby supporting the grid and acting as a potential storage for clean energy - but it will only be economically viable if we upgrade the system first. In a ...

#### A 'half-hearted' solution to one-sided heart failure—Soft robotic system provides support

November 22, 2017

Soft robotic actuators, which are pneumatic artificial muscles designed and programmed to perform lifelike motions, have recently emerged as an attractive alternative to more rigid components that have conventionally been ...

#### Uber reveals cover-up of hack affecting 57M riders, drivers (Update)

November 22, 2017

Uber is coming clean about its cover-up of a year-old hacking attack that stole personal information about more than 57 million of the beleaguered ride-hailing service's customers and drivers.

#### US regulator unveils plan to end 'net neutrality' (Update)

November 21, 2017

The top US telecom regulator formally unveiled plans Tuesday to roll back "net neutrality" rules adopted in 2015 aimed at treating all online traffic equally.

#### New human mobility prediction model offers scalability, requires less data

November 21, 2017

A new method to predict human mobility—which can be used to chart the potential spread of disease or determine rush hour bottlenecks—has been developed by a team of researchers, including one from Arizona State University.

#### Volvo to supply Uber with self-driving cars (Update)

November 20, 2017

Swedish carmaker Volvo Cars said Monday it has signed an agreement to supply "tens of thousands" of self-driving cars to Uber, as the ride-sharing company battles a number of different controversies.

## 5 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

##### fixer
not rated yet Jan 10, 2011
Sim city...
##### nuge
not rated yet Jan 10, 2011
It won't be long until Google Earth 3D is launched
##### scidog
not rated yet Jan 11, 2011
i'm sure this is just the up front, public release of a system that the military uses to look thru Kim Jong il's bathroom window.
##### nevermark
not rated yet Jan 11, 2011
Next Grand Theft Auto in a true to life recreated city? That would be something to learn a real city through a game.

I vote for Chechnya Russia or Ciudad Jaurez, Mexico. Either one would make New York, Miami or Los Angeles look like an organized crime holiday.
##### El_Nose
not rated yet Jan 13, 2011
Combine this with Microsoft Image Composite Editor and Multi-Image Fusion and you could have something unbelieveable ...

goto to youtube and type in the keywords Multi-Image Fusion and watch the video

now combine that concept with lets say Google Earth + every picture on the internet that has a shot of landscape -- I'm talking google's image archive + a full web crawl of facebook and flikr and think of what you could create.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.