Pulsed sandwich holography.
A new method is introduced which utilizes sandwich holography combined with a pulsed laser. In a special rotating hologram holder two plates sandwiched together are exposed through a slit during the double pulse operation of a laser. The two pulses are separated by less than 1 msec. Afterward, in an evaluating holder, one plate is rotated in relation to the other so that the images from the two pulses are overlapped. Then the two plates are glued together. If the emulsions are separated, fringes caused by object tilt between the two pulses can be eliminated by an analogous, but much larger, tilt of the sandwich hologram during reconstruction. Even the direction of tilt, forward or backward, is found this way.
Bjelkhagen
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