Christoph B. Burckhardt

Formation and Inversion of Pseudoscopic Images

The reconstruction from an integral photograph is pseudoscopic. It is usually inverted into an orthoscopic image by a second recording and reconstruction process. Some schemes are described which perform this inversion without the need for a second recording. All schemes use some form of autocollimating screen, i.e., a screen which reflects a ray of light back onto itself. The inversion can either be formed on the scene (inversion from orthoscopic to pseudoscopic) before the integral photograph is recorded or it can be performed on the pseudoscopic reconstruction. Some theoretical considerations concerning the optimum screen are given. The relation between these schemes and integral photography,image dissection, and a previously proposed scheme are given.

Beaded plate recording of integral photographs.

The beaded plate is a simple inexpensive medium for recording integral photographs. It consists of a monolayer of glass balls laid down on a photographic emulsion. The preparation of beaded plates is described. The beaded plate is exposed in the central plane of a pseudoscopic real image reconstructed from a hologram or an integral photograph. When the beaded plate is developed in reversal and illuminated from the rear, a three-dimensional image is produced. Experimental results are given and some of the problems are discussed.

A bleach process for high-efficiency low-noise holograms.

A bleach process is described which gives high-efficiency, low-noise holograms. Potassium ferricyanide is used as the bleaching agent. The main differences between this process and earlier uses of potassium ferricyanide for bleaching are a different developer and a special drying procedure. The following values for the efficiency were obtained: 45% for a plane grating, 25% for a hologram of a diffuse subject, and between 10% and 15% for holograms of data masks. The bleached holograms are stable in an ordinary laboratory atmosphere but degrade in very high humidity.