Robert Boschgmbh

Bts Broadcast Television Systems Gmbh

Friedrich Zimmermann

Dieter Poetsch

Klaus Lehmann

Klaus D M/u/ Ller

Gerd Bock

Hans-Wilhelm Zappen

Jurgen Klink

Andreas Hess

Herbert Zettl

Hans-W Zappen

R, G and B outputs from the corresponding preamplifiers of a television camera are supplied to a non-additive mixer (NAM) circuit for continuous selection of the greatest of the three outputs and the selected output is continuously supplied to a set of 9 electronic switches each selecting out a subdivision of the picture field (a, b . . . i). The switched outputs for each of the subfields are then provided to respective subfield measurement detectors which each produce an average value output and a peak value output. These are stored into subfield buffer units and then read out through a multiplexer and an analog to digital converter to a microprocessor. The various values are compared with corresponding past values for selecting between various measurement schemes for obtaining a camera diaphragm control signal, namely spot measurement, center-emphasized integral measurement and selective field measurement. Except when a decision for no setting change is made, the selected scheme of measurement is used to obtain a control signal from the average and dynamic range values of the several subfield video signals.

Automatic aperture control of a television camera

To eliminate or suppress amplifier noise in amplifiers (6, 7) connected to a semiconductor light sensor, for example of a charge coupled type, in which the noise introduced by the amplifiers has a frequency spectrum which is low with respect to the clock frequency of operation of the sensor, the minimum value signal from the light sensor, as amplified, is determined; the maximum value of the signal, as amplified, is determined; and a reference is derived based on the minimum value, for example by clamping the minimum value, or utilizing the minimum value as a dynamic reference for subtraction from the maximum value, to thereby eliminate the effect of low-frequency shift of signals due to low-frequency noise of the amplifiers; various circuits may be used, such as clamping circuits (FIG. 3), threshold or non-additive mixing circuits (FIGS. 4, 5) coupled to a subtraction stage (24), band-pass filtering and envelope demodulation (FIG. 6: 28, 29, 30) or synchronous demodulation (FIG. 7: 34, 35) using the scanning clock frequency (36, 37) for synchronous demodulation, coupled with frequency limiting the output to, for example, one-half clock frequency in a low-pass filter (39).

Method and system to reduce low-frequency noise in semiconductor sensors

A method and circuitry for reading out data from a TV pickup (image sensor) designed for the 525-line television standard, and operated in accordance with a line interlace process by once-repeated read-out of each line. In order to adapt the TV pickup (image sensor) to a 625-line television standard, every third line scan is repeated twice, i.e., every third line is read out three times. Both analog and digital circuits are presented.

Method and circuit for reading-out data from a television pickup (image

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Rossdorf, Germany

Friedrich Zimmermann