Flatlands fly to third dimension

Researchers at the Technion-Israel Institute of Technology have developed fast software which turns flat-looking satellite pictures into landscapes with a realistic three-dimensional look. The landscape can be shown as it would appear from any angle or height.

Craig Gotsman and Gennady Agranov of the Technion's faculty of computer science worked together on the special software. John Hall of the Geological Survey of Israel prepared digital terrain models from detailed topographic maps. Richard Cleave of Rohr Productions in Nicosia provided satellite data obtained by merging images from the American Landsat 5 and French SPOT satellites.

The satellite imagery was eventually "draped over" the digital terrain models to create realistically coloured high-resolution bird's eye views of scenes of the Holy Land. Some of the images were published in National Geographic magazine on account of the unique insights they give into the geography of the Holy Land.

The images are in colour and show features as small as 10 metres. The researchers achieved this by combining Landsat 5 colour images, which have a resolution of 30 metres, with grey-scale data recorded at 10 metre resolution by a French SPOT satellite. The researchers have already made movies of imaginary flights over the country, recorded on video discs. But the ultimate aim of the research is to improve the quality and speed of flight simulation, which will require the images to be rendered in real time. While similar work exists in other countries, the Technion researchers believe they lead with their technology, which they hope will deliver professional quality flight simulation on computers costing less than $20,000. According to Dr Gotsman, "NASA is working towards the same goals, but their parameters are different. We are aiming for speed and quality. The question is, at what speed can you produce those images and what is the quality of the image?" To achieve that combination requires either a powerful computer or some clever software. "We've come up with a bunch of algorithms which produce quality and speed," says Dr Gotsman. "The same algorithms may be used in flight simulation."

The project cost several hundred thousand dollars and was funded by several Israeli government agencies, including the ministries of science and industry, and a number of industrial sponsors. Although the main aim of the software is flight simulation, it can also be used for other applications, Dr Gotsman says. "It would be good for urban planning, but the most exciting thing is to 'fly' through the data - not just through one picture, but as a moving picture."