In "Chip Miniaturizes Holography," Technology Review says that Japanese researchers have developed a hologram generator on a single circuit board. The electroholographic system consists of a special-purpose computational chip and a high-resolution, reflective mode, liquid-crystal display panel as a spatial light modulator. With this system, they were able to generate an hologram at a resolution of 800x600 in half a second for an object of 1,000 points. Their solution is scalable in two ways: the computation is done in parallel streams, and several chips can work on a single hologram. The researchers think that there will be real-time 3D applications for television or medical imaging within five to ten years.
Below are two images of the device (Credit: Tomoyoshi Ito, Chiba University; Tomoyoshi Shimobaba, Institute of Physical and Chemical Research (RIKEN)).
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Here is a diagram of the optical setup including the computer-generated hologram (CGH) calculation system. |
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And here is a photograph showing the physical top view of the one-unit system board. |
Here are some details about this hologram generator, provided by Technology Review.
The researchers' system consists of a special-purpose computer chip and a high-resolution liquid-crystal display panel. The system generates holograms on the screen with a half second delay for an object that consists of 1,000 points, according to the researchers.
The key to generating a hologram in near real-time is being able to compute a very large number of pixels very quickly. A good three-dimensional picture must have a dot pitch, or pixel size, of less than 5 microns to look right to both eyes. A hologram that is 10 centimeters by 10 centimeters with a 5-micron dot pitch contains 20,000 by 20,000 pixels.
A real-time reconstruction of an image with that many pixels requires a computation speed faster than today's computers by one million times, according to the researchers. The researchers' scheme speeds the computation by programming the chip to calculate the data in parallel streams. The scheme is also scalable; multiple chips can be used to increase the speed of the system or the size of the image.
The research paper has been published by the Optics Express journal. Here is a link to this paper, "One-unit system for electroholography by use of a special-purpose computational chip with a high-resolution liquid-crystal display toward a three-dimensional television."
You'll be able to read the full paper (PDF format, 6 pages, 632 KB) or watch a short video (312 KB). Below is the text of the abstract.
We developed a one-unit system for electroholography, which consists of a special-purpose computational chip and a high-resolution, reflective mode, liquid-crystal display panel as a spatial light modulator. We implemented them on one board whose size is approximately 20 cm × 20 cm. The chip makes a computer-generated hologram whose size is 800 ×600 at nearly real time (~0.5 s) for an object consisting of 1000 points. The pixel pitch of the display panel is 12 µm, and the resolution is 800 × 600. It reconstructs a three-dimensional motion image whose size is approximately 3 cm × 3 cm × 3 cm. The system can be readily scaled up, since the units consisting of the chip and the display are easily set in parallel.
Sources: Technology Research News June 14, 2004; Optics Express, May 3, 2004, Vol. 12, No. 9, Pages 1788 - 1793
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