Two Japanese scientists have developed technology they hope will one day turn the humble telephone booth into a high-tech chamber for beaming holographic images. At a Tokyo University laboratory, a woman stands inside a booth where a 360-degree digital camera surrounding her face sends data to a cylindrical tube. Soon, she appears to be staring out from the tube. Viewed from the side, only the side of her head is visible. Go round to the back, and only her hair can be seen.

"We can see the 3-D image as if it's inside the cylinder," said Susumu Tachi, a Tokyo University professor of computer science and physics. With the device, "we can have a family gathering or conference at a remote place".

Mr Tachi and colleague Tomohiro Endo developed the cylinder - dubbed SeeLinder - by combining fibre optics, electronics and white LEDs.

The hologram cylinder resembles a zoetrope, a primitive motion-picture wheel.

Inside the cylinder, an outer wheel with vertical slits revolves clockwise at a fast clip, while an inner wheel moving counterclockwise at a slower speed lined vertically with LEDs projects thin slices of a person's face. The rapid succession of image slices seen through the slits produces the illusion that the viewer can see the person's entire face at once, in 3-D.

The image appears to be about 20cm in diameter and 25cm high.

There are limitations. Looking at the cylinder from above or below doesn't change the image, and the hologram is still fuzzier than modern TV screens.

It's also pricey. One cylinder costs 10 million ($124,000), though Tachi and Endo expect that to fall if the gadget is ever mass-produced.

The technolgoy was being refined, and given demand, the technology could be commercialised soon, Mr Endo said.

"We think this can be on the market in the near future," he said.