Abstract: Process and apparatus for the white balancing of the opto-electrical converters of the scanning elements in reproducers for the point-by-point and line-by-line scanning of black and white documents and color documents. The light from the illuminant of the documents being scanned is converted in the opto-electrical converters into video signal levels or color signal levels, and the sensitivity or amplification of the opto-electric converters is so set that the video signal levels or color signal levels correspond to preset reference signal levels. The inconvenient process of scanning the illuminant of the document to be scanned, in order to obtain the light required for white balance, is replaced by a process by which the light from the scanning light source may be dimmed by means of a regulable iris diaphragm, thus corresponding to the scanning light from the illuminant of the document to be scanned.

Abstract: The present invention relates to a method and to an apparatus for acoustic supervision of the adjustment of a light bundle with respect to position and/or direction. A measuring surface lying in the beam path of the light bundle is divided into sectors. Apexes of centering angles of the sectors define a rated position. Light components of the light bundle incident into the individual sectors are measured opto-electronically as a measure of the positional deviations. Oscillations are generated for the individual sectors. Respective parameters of the oscillations are modified dependent on the measured positional deviations, and the modified oscillations are made audible as measuring tones. For the directional adjustment of the light bundle, the light bundle is focused onto the measuring surface whereby apexes of the centering angles of the sectors define the point of penetration of the rated direction through the measuring surface.

Abstract: A method and apparatus for acoustic supervision of adjustment of a light bundle composed of component beams with respect to its intensity distribution in an expanse of a reference plane situated in a beam path at right angles to an optical axis of the light bundle. Intensity values I of the component beams lying at a margin of the light wave are measured and the differential intensity values .DELTA.I are identified according to amount and operational sign. An oscillation is generated whose parameters are modified dependent on the amounts and operational signs of the respective differential intensity values. The modified oscillation is made audible as a distinguishable measuring tone for amounts and operational signs of the differential intensity values .DELTA.I.

Abstract: A method and apparatus for acoustic supervision of adjustment of a light bundle with respect to its intensity distribution in a reference plane which is at right angles to the optical axis of the light bundle. The reference plane is subdivided into surface elements. The intensity values corresponding to a rated intensity distribution are prescribed and stored for the individual surface elements of the reference plane. The intensity values for the individual surface elements respectively existing in the adjustment are successively measured in rapid cyclical succession. The intensity deviation from the prescribed intensity value is identified and stored for each surface element. The stored intensity values are read-out in slow cyclical succession and are made audible as measuring tones for the supervision of the adjustment.