Abstract: A wave front sensor having a focusing optical system (1), a perforated diaphragm (2) with a plurality of perforations (21) situated simultaneously in the beam path (3), in an encoded arrangement, in particular according to and a cyclic Hadamard code, a device (22) for advancing the perforated diaphragm (2), so that a multiplicity of different encoded arrangements of perforations (21) are situated successively in the beam path (3).

Abstract: Process and apparatus for testing optical components (12) or systems which are contained in an apparatus consisting of a focusing optical system (1) and a space-resolving light detector (2) close to the focal plane thereof, it being provided that a source (3), containing a collimator (32), for a narrowly delimited precisely parallel light beam with a plane wavefront is moved rectilinearly in a plane parallel to the wavefront, at a plurality of positions of the source (3) the signal of the light detector (2) is determined, tilting movements of the source (3) perpendicular to the line direction are detected by an apparatus with a second collimator (52) and space-sensitive detector (51), and the aperture of the optical system (1) is scanned twice with line directions rotated relative to one another through approximately 90.degree., and in addition an individual line coming close to the axis of rotation is scanned in a position rotated through approximately 45.degree..

Abstract: The measuring device is used for determining a relative position between a first item and a second item or the image thereof. The items are displaceable or rotatable relative to one another. The first item has a code carrier, which is arranged along a path. The code carrier is provided with a code pattern at right angles to the path. The second item has a code reader oriented on the code carrier path. A computer is connected downstream of the code reader and has means for quantifying the signal supplied by the code reader and for comparing with a stored code image of the code carrier, as well as for calculating the relative position from the comparison result. This measure permits automatic reading of the position, accompanied by a very high measuring accuracy. The measured result can be digitally displayed and, if required, can be directly stored on a data carrier and/or can be further processed in a computer.