| 摘要 |
A varifocal mirror is typically comprised of a thin aluminized Mylar film that is stretched over a loudspeaker driven sinusoidally at low frequencies. When an object is placed a short distance from the film and the film is oscillated, the position of the image of the object in the mirror will be constantly swept back and forth in the image space with an amplitude typically several times the mirror displacement. In the system herein described a first varifocal mirror is used to sweep a virtual image of a three-dimensional scene that is to be recorded through the first of a pair of conjugate planes of a large aperture, low f-number lens. Inasmuch as such a lens has a small depth of field, only one depth plane of the scene at a time will be in focus at the second, of the pair of conjugate planes of the lens. Thus, as the varifocal mirror oscillates, the images of a series of two-dimensional depth planes are projected onto a back projection screen placed at the second of the conjugate planes. These images can there be recorded for subsequent storage or transmission. At the other end of the system, the images are projected into an appropriate display screen and this screen is viewed through a second varifocal mirror vibrating at the same frequency as the first mirror but 180 DEG out of phase. Consequently, this mirror forms a series of two-dimensional virtual images each located in the correct depth plane so as to recreate the original three-dimensional scene.
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