Directional image processing using a pinhole camera with a rectangular aperture.

This paper describes a new method of directional image processing based on a pinhole camera with a rectangular aperture.

Incoherent 2-D spatial filtering of screened images.

Incoherent 2-D spatial filtering can be achieved by means of an astigmatic system. Double screened pictures can be easily descreened with this method. Theoretical analysis and experimental results are presented.

Visual speckle technique for alignment and centering of a translucent rough surface.

A simple visual method is described which is based on the direct analysis of speckle pattern movement. It permits aligning a transparent diffuser, placing its rotation axis on the mean plane of the rough surface and simultaneously determining the optical axis. As a consequence, the direction of the illuminating light beam can be determined.