Researchers isolate 'shared elements' to speed 3D map rendering

Google Maps and Virtual Earth provide increasingly realistic and useful descriptions of the world, but present several technology challenges, the researchers’ state.

These challenges relate to the bandwidth needed to transmit detailed photographic images over the Internet and the memory space in consumer devices to store and render these types of images.

Researchers from Microsoft and the Georgia Institute of Technology hope that bandwidth and memory constraints can be reduced by exploiting what they call a
‘significant’ repetition of content in these types of images.

Textures “often contain repeated patterns such as bricks, tiles and windows,” say the researchers, and traditional image compression schemes aren’t designed to factor in and take advantage of these repetitive elements.

“Our goal is to exploit the tremendous sharing of imagery features, both within individual images and across collections of images,” explains Hugues Hoppe, a principal researcher in the Graphics Group within Microsoft Research and co-author of the paper.

“For instance, building façades often contain repeated elements, such as windows and bricks. And multiple images often reveal the same surfaces, only just slightly deformed.

“Our approach is to factor these elements efficiently so as to represent them only once,” says Hoppe.

Eliminating the rendering of repeated – ‘redundant’ – content will enable larger images to be rendered within existing device memory envelopes.

The approach also leaves open the option for further compression of the image, claims Hoppe.

“In a sense, our technology can be seen as orthogonal to traditional image compression such as JPEG,” Hoppe says.

“While JPEG looks for correlation at a local scale in the image, such as areas of constant color, we look for correlation of features at large scales.

“We think that this an exciting technological direction that will enable the representation of complicated 3-D environments on affordable devices.”

The paper , entitled ‘Factoring Repeated Content Within and Among Images’, is one of 13 from Microsoft Research to be accepted for SIGGRAPH 2008, the Association for Computer Machinery’s annual conference for its Special Interest Group on Graphics and Interactive Techniques.

googleimagemapsmicrosoftsoftware