Japanese scientists are using a Sun Microsystems Sun-4 workstation to develop a system that prints out holograms of computerdesigned objects, according to a recent report in the New Scientist. The Sun-4 is said run at 10 times the speed of standard personal computers, but it still takes 50 hours to record a hologram. The team developing the new system is based at the Tokyo Institute of Technology, and it is collaborating with Matsushita Electric Industrial Co to resolve some of the visual problems which include contrast between black and white and different shades of grey. The system itself begins with a designer drawing an object on the computer through a grid wire. The system scans the object through one hole on that grid and sends a signal to a liquid crystal display. A laser beam passes through the display on to a photographic plate and crosses a second beam at the surface of the plate. The collision creates a pattern which forms a hologram of the object as it was viewed through the hole in the grid. This process is repeated until the object has been viewed through every hole and reconstructed in hologram form. These holograms are equivalent to pixels in a two dimensional image, and are known as voxels. These voxels enable the user to view the image from two perspectives since each eye focuses on different voxels and produces different views, and the view from each voxel changes as the viewer changes his position. The drawback is the time it takes to transfer data from the computer memory to the memory of the printer, although scientists are optimistic that storing pictures on optical disks and playing them back later could cut that time considerably. The Japanese team believes that with six optical heads, the time to generate a hologram of 1,000 by 1,000 voxels could be reduced to less than five hours.
