Computing Now Exclusive Content — April 2010

News Archive

July 2012

Gig.U Project Aims for an Ultrafast US Internet

June 2012

Bringing Location and Navigation Technology Indoors

May 2012

Plans Under Way for Roaming between Cellular and Wi-Fi Networks

Encryption System Flaw Threatens Internet Security

April 2012

For Business Intelligence, the Trend Is Location, Location, Location

Corpus Linguistics Keep Up-to-Date with Language

March 2012

Are Tomorrow's Firewalls Finally Here Today?

February 2012

Spatial Humanities Brings History to Life

December 2011

Could Hackers Take Your Car for a Ride?

November 2011

What to Do about Supercookies?

October 2011

Lights, Camera, Virtual Moviemaking

September 2011

Revolutionizing Wall Street with News Analytics

August 2011

Growing Network-Encryption Use Puts Systems at Risk

New Project Could Promote Semantic Web

July 2011

FBI Employs New Botnet Eradication Tactics

Google and Twitter "Like" Social Indexing

June 2011

Computing Commodities Market in the Cloud

May 2011

Intel Chips Step up to 3D

Apple Programming Error Raises Privacy Concerns

Thunderbolt Promises Lightning Speed

April 2011

Industrial Control Systems Face More Security Challenges

Microsoft Effort Takes Down Massive Botnet

March 2011

IP Addresses Getting Security Upgrade

February 2011

Studios Agree on DRM Infrastructure

January 2011

New Web Protocol Promises to Reduce Browser Latency

To Be or NAT to Be?

December 2010

Intel Gets inside the Helmet

Tuning Body-to-Body Networks with RF Modeling

November 2010

New Wi-Fi Spec Simplifies Connectivity

Expanded Top-Level Domains Could Spur Internet Real Estate Boom

October 2010

New Weapon in War on Botnets

September 2010

Content-Centered Internet Architecture Gets a Boost

Gesturing Going Mainstream

August 2010

Is Context-Aware Computing Ready for the Limelight?

Flexible Routing in the Cloud

Signal Congestion Rejuvenates Interest in Cell Paging-Channel Protocol

July 2010

New Protocol Improves Interaction among Networked Devices and Applications

Security for Domain Name System Takes a Big Step Forward

The ROADM to Smarter Optical Networking

Distributed Cache Goes Mainstream

June 2010

New Application Protects Mobile-Phone Passwords

WiGig Alliance Reveals Ultrafast Wireless Specification

Cognitive Radio Adds Intelligence to Wireless Technology

May 2010

New Product Uses Light Connections in Blade Server

April 2010

Browser Fingerprints Threaten Privacy

New Animation Technique Uses Motion Frequencies to Shake Trees

March 2010

Researchers Take Promising Approach to Chemical Computing

Screen-Capture Programming: What You See is What You Script

Research Project Sends Data Wirelessly at High Speeds via Light

February 2010

Faster Testing for Complex Software Systems

IEEE 802.1Qbg/h to Simplify Data Center Virtual LAN Management

Distributed Data-Analysis Approach Gains Popularity

Twitter Tweak Helps Haiti Relief Effort

January 2010

2010 Rings in Some Y2K-like Problems

Infrastructure Sensors Improve Home Monitoring

Internet Search Takes a Semantic Turn

December 2009

Phase-Change Memory Technology Moves toward Mass Production

IBM Crowdsources Translation Software

Digital Ants Promise New Security Paradigm

November 2009

Program Uses Mobile Technology to Help with Crises

More Cores Keep Power Down

White-Space Networking Goes Live

Mobile Web 2.0 Experiences Growing Pains

October 2009

More Spectrum Sought for Body Sensor Networks

Optics for Universal I/O and Speed

High-Performance Computing Adds Virtualization to the Mix

ICANN Accountability Goes Multinational

RFID Tags Chat Their Way to Energy Efficiency

September 2009

Delay-Tolerant Networks in Your Pocket

Flash Cookies Stir Privacy Concerns

Addressing the Challenge of Cloud-Computing Interoperability

Ephemeralizing the Web

August 2009

Bluetooth Speeds Up

Grids Get Closer

DCN Gets Ready for Production

The Sims Meet Science

Sexy Space Threat Comes to Mobile Phones

July 2009

WiGig Alliance Makes Push for HD Specification

New Dilemnas, Same Principles:
Changing Landscape Requires IT Ethics to Go Mainstream

Synthetic DNS Stirs Controversy:
Why Breaking Is a Good Thing

New Approach Fights Microchip Piracy

Technique Makes Strong Encryption Easier to Use

New Adobe Flash Streams Internet Directly to TVs

June 2009

Aging Satellites Spark GPS Concerns

The Changing World of Outsourcing

North American CS Enrollment Rises for First Time in Seven Years

Materials Breakthrough Could Eliminate Bootups

April 2009

Trusted Computing Shapes Self-Encrypting Drives

March 2009

Google, Publishers to Try New Advertising Methods

Siftables Offer New Interaction Model for Serious Games

Hulu Boxed In by Media Conglomerates

February 2009

Chips on Verge of Reaching 32 nm Nodes

Hathaway to Lead Cybersecurity Review

A Match Made in Heaven: Gaming Enters the Cloud

January 2009

Government Support Could Spell Big Year for Open Source

25 Reasons For Better Programming

Web Guide Turns Playstation 3 Consoles into Supercomputing Cluster

Flagbearers for Technology: Contemporary Techniques Showcase US Artifact and European Treasures

December 2008

.Tel TLD Debuts As New Way to Network

Science Exchange

November 2008

The Future is Reconfigurable

New Animation Technique Uses Motion Frequencies to Shake Trees

by George Lawton

UK researchers have developed a new way of making high-quality animations of trees from video footage. Animators for films or computer games could use this approach, called animated foliage, to automatically generate trees that move in a natural way. Animated foliage overcomes many difficulties in creating lifelike tree movements, which normally require hand drawing.

The technique was developed by senior lecturer Peter M. Hall and engineering doctorate student Chris Li at the University of Bath and funded by the UK Engineering & Physical Sciences Research Council. It lets an animator draw a circle around an image of a tree in a single video frame. A Matlab program then uses machine-vision techniques to automatically extract a 3D model of the tree from the rest of the footage. The user can then specify the desired tree movement, even making it dance to music.

Tree-modeling research has been significant over the years. Hall said this project advances the field in five ways. First, it collects the data from video, so that the motion is inherent to the trees rather than modeled afterward by specifying a wind field. Second, the program minimizes the amount of human interaction, making the technique suitable for novices. Third, it can generate new trees automatically. Additionally, it uses a unique 3D reconstruction technique that avoids many problems seen in other animation techniques. Finally, it models tree motion as frequencies, shaking the trees rather than blowing on them.

Tracking the Trees

The research was partly funded to develop a tracker program that follows objects in a video. Hall said, "No one in the world knows how to do that for the vast variety of objects, and the way people do track objects remains a mystery."

The animated-foliage program tracks branches by following the big branches first, then the medium-size child branches, and so on down to small branches. This tracker isn't sensitive enough to go all the way to twigs.

One part of the tracker works out how the branches are connected together. If the tracker gets this wrong, then it can't follow the smaller branches, so it tries again until it gets it right. "Once the branching structure is right and the tracker can follow the tree, it's easy to collect data about the swaying motion," said Hall.

Users initiate the process by outlining the tree they want with a mouse cursor.

Modeling the Motion

Once the program has captured data about the swaying motion, it builds a probabilistic generative model for the fork shapes in tree branches. The model uses information about a branch and its two children that make up the fork. For a given sort of tree, such as an oak or pine, the fork triangles must be more or less the same shape, such as broad and fat or tall and thin.

To make a new tree, the program makes new forks and pieces them together like bricks. It can grow new trees by adding forks that start at the trunk and branch upward. Unlike the tracker, the modeler can make a tree all the way to its twigs.

One challenge Hall and Ping faced was stopping the tree from leaning to one side as it grows. They solved this program by reusing the original, user-created tree outline and fitting the growth pattern to fill that space as evenly as possible. Users can create a differently shaped tree by drawing a new outline of the original.

"This way is much better than just moving the branches of the original tree [from video] by some small random amount," noted Hall. "If we did that we'd just get the same tree again and again, but our way gives a unique individual every time."

Shaken Not Blown

The modeler can control tree movements for different weather conditions and seasons. It copies a tree's movement by extracting the dominant few motion frequencies, using a Fourier transform of the angular velocity. It looks at the shape of branch forks to compute the average shape, along with how much and in what ways it can change.

The researchers noted that the trees sway with resonant frequencies. As a parent branch sways, it pushes its children in just the right way, much like a human pushes a child's swing in time to work properly.

To simulate different weather conditions, the model adjusts the power in the push. To get the tree to dance, the modeler pushes the tree in time to the music frequencies. Hall said, "This is very different from state-of-art trees, which force users to specify a wind. It would be, at best, very hard to make trees dance that way."

Animated-foliage trees are initially built bare of leaves. The tracker sees through the leafy canopy to make a guess about the branches below. The program can add leaves as polygons that approximate the original tree’s texture. Users can also add other shapes, such as blossoms and fruit, and render trees as if they were painted or drawn.

Some Limitations

Hall said the technique has some weaknesses. The video must show a leafy tree. To change this, they would need to develop a new tracker.
All the tree forms have one parent and two children. This works well for most trees, but splitting branches into three or more children on occasion would increase the model's accuracy for a larger range of trees. However, it would also require a more complex statistical model.

Another problem is that the branch shapes are guesses and might not be fully accurate. Animators, gamers, and architects are usually satisfied with the results, but tree scientists would be disappointed.

The branches themselves do not bend. Instead, they rotate around the forking point they come from. To bend a branch more, users add more points along the branch’s length.

Hall would like to apply the same user-interface style to create models of other object types, such as clouds and fire. How to capture such object motions remains an open question. Researchers have only recently begun using dynamic textures to model natural phenomena.

There are no definitive plans for the animated-foliage research, except to use it as a platform for further study. A finished application would require a better user interface and translation into a standard language such as C++, Hall said. "Turning research code into a product takes money and time we don't have, but we'd be delighted to work with a partner to create a product."

George Lawton is a freelance journalist based in Guerneville, CA. Contact him at