Abstract: A device for detecting deformations in the surface of a workpiece includes a light source for illuminating the surface of the workpiece; a detector situated at a fixed predetermined distance from the light source and a displacing arrangement for effecting a relative movement between the workpiece and the light source. The detector comprises a photoreceiver for receiving reflected light from the workpiece and for generating a first output signal having a frequency dependent from the deformation of the workpiece. The photoreceiver is position-sensitive perpendicularly to a direction of the relative movement. A frequency analyzer is operatively connected to the receiver for receiving the first output signal from the photoreceiver and for generating a second output signal when the frequency of the first output signal exceeds a cutoff frequency.

Abstract: An optoelectronic viewing system for imaging a field of view on a monitor includes a telescope for generating an optical image of the field of view, a scanning device for electronically scanning the optical image and an electronic evaluation unit for processing the scanning signals and displaying the image on the monitor. In order to create a field of view which is large enough for surveillance with a long-range viewing system that has sufficient resolution, a mirror system for pivoting the direction of beam incidence in the vertical and horizontal direction is placed ahead of the telescope. The mirror system is driven for reproducibly and consecutively passing through a succession of fixed predetermined pivoted positions. The scanned image signals obtained from the individual pivoted positions are combined into a field of view.

Abstract: A method and apparatus for compensating sensitivity fluctuations in signals received from respective groups of hydrophones for the purpose of subsequent signal processing, the groups being arranged in a predetermined sequence (0, 1, 2, . . . i) to form a transducer arrangement, wherein the received signals are influenced by the sensitivity of the hydrophones and/or the gain of preamplifiers connected to the outputs of the hydrophones. The energy value (W.sub.i) for the received signals of each group of hydrophones is determined and a median energy curve (W.sub.m (.theta.)) is derived from the energy values (W.sub.i) as a function of the sequence of the groups of hydrophones. A correction value is formed for the signals received from each group of hydrophones from a comparison of the respective energy value (W.sub.i) with the energy curve (W.sub.m (.theta.)) and the received signals are corrected with the correction value.