CAMBRIDGE, Mass. (AP) _ Massachusetts Institute of Technology researchers on Tuesday unveiled a refinement in holography that allows them to project a three-dimensional picture in the air.

Previous holograms were confined to special chambers, usually made of glass.

The MIT scientists said their floating images, much like one depicted in the science-fiction movie ''Star Wars,'' can be designed on a computer or transferred from sources like a medical CAT-scan to project body organs.

''Using our system, the image is completely projected into space, suspended ... in front of the observer,'' Dr. Stephen A. Benton said of his development, a complex combination of lasers, fiberoptics, mirrors and computers.

Speaking at a news conference, the MIT professor cautioned that the holographic technique was still at an early stage of development and gave no estimate of when the technique would yield practical applications.

He predicted everyday use by surgeons to examine the body and by architects who could have realistic depictions of proposed buildings.

Automobile designers would be able to use computer-generated holograms instead of clay models, he said.

The remaining goal of the three-year, $450,000 research program is perfecting a sharper image in full color and up to 3 1/2 -feet long, he said.

At present the holograms are less than 12 inches long and only one hue.

''We have proved that the principle works and we are going on from there,'' he said. ''Holographic technology is about where photography was in the 1860s. Perhaps someday these images will come out of laser-age copying machines for a few dollars apiece.''

Benton and two assistants displayed floating green holograms of a sports car and a hip joint.

''There have been three-dimensional holograms before,'' said Mark Holzbach, an assistant. ''But this is the first undistorted, wide-angle holographic image that's out in the viewer space. This provides a much more realistic and vivid image of something that really may not exist.''

The holographic stereogram is beamed up by laser light bounced off a semicircle of film, creating a walk-around view of the object in space, instead of behind a flat or cylindrical piece of plastic or glass.

While viewers cannot go behind the image, they can have a 180-degree viewing field, which allows them to examine it from the front and sides.

To create the three-dimensional hologram, the MIT Media Laboratory researchers compute nearly 1,000 views of the image. The side-to-side views are recorded on 35mm film, which is processed and taken to a laser laboratory.

There, each image is projected onto holographic film at a specific angle. Once processed, the film is affixed to a plexiglass semicircle, or alcove, illuminated from behind with laser light reflected by a curved mirror.

All of the angular views are reproduced simultaneously, overlapping to provide a solid-appearing image suspended within the alcove.

''We compute all the views and fire them into a hologram, which later fires them back to our eyes,'' Benson said.

It several days between formulating a computer design and projecting a hologram in space, but, Benton said, ''We want to be able to see on a computer one day, and as a walk-around image hanging in space the next day.''