Abstract: The correction consists in correcting the overall luminance, while retaining the original chromaticity of the analyzed picture. For this purpose, the device according to the invention comprises a correcting circuit receiving the color signals V.sub.e1, V.sub.e2 and V.sub.e3 and supplying corrected color signals, a matrixing circuit supplying the overall luminance signal V.sub.e, and a control circuit calculating eight transfer parameters defining the transfer function F, which transforms the signal V.sub.e into a signal F(V.sub.e) covering the scale of luminances in accordance with an equal distribution in order to satisfy the optimum vision conditions. The control circuit processes the signal (F(V.sub.e)/V.sub.e) and the correcting circuit supplies corrected color signals respectively corresponding to the products V.sub.e1 .multidot.(F(V.sub.e)/V.sub.e), V.sub.e2 .multidot.(F(V.sub.e)/V.sub.e) and V.sub.e3 .multidot.(F(V.sub.e)/V.sub.e).

Abstract: The device comprises a variable-characteristic nonlinear four-terminal network having one input for receiving a video signal V.sub.e and eight inputs for controlling transfer parameters. Statistical analysis of the amplitude of the signal V.sub.e permits acquisition of the luminance distribution function of said signal. On the basis of this distribution function, computing means determine the values of the transfer parameters to be applied to the control inputs of the four-terminal network in order to deliver at the output of the network a video signal V.sub.s which extends over the entire luminance scale and has the desired distribution for satisfying optimum conditions of vision.

Abstract: A method and apparatus for positioning an object in space in such a manner as to permit duplication of the positioning in a precise position wherein three characteristic points on the object wherein the coordinates of the points are determined and are electrically synthesized for generation of a signal for reproducing the points on the coordinates, and utilizing a television camera and monitor forming an image of the object on the screen and causing the points of the object to coincide with the reference points by means of a photosensitive sensor in such a manner that the characteristic points on the body are displaced so as to coincide with the synthesized points on the television screen.