Abstract: For making use of interactive services, it is essential that the individual needs of the users be satisfied while taking the security aspect into consideration. The method resolves this in that a connection setup to the user is only handled when an authorization of the appertaining user can be verified based on the comparison of two numerical values.

Abstract: An arrangement for optimized weighting of transmitted transformation coefficients in transformation coders for the purpose of minimizing convolution distortions in the transformation coding of image signals for the purpose of a data reduction and/or for the purpose of achieving a prescribed channel rate, has weighting circuitry whereby coefficients to be transmitted are additionally subjected to a weighting or windowing; and the selection of suitable weighting factors which effect a minimization of the convolution distortions in the reconstructed image is executed, dependent on the plurality of coefficients to be transmitted.

Abstract: Method and apparatus for the reduction of picture data for digital video signals comprising a processing of the signals by means of block by block transformation method so that a transformed and quantized signal which was generated at a time t-1 and placed in an image storage is subtracted from a transformed signal that occurs at a time t and whereby the difference signal obtained is subject to quantization and the quantized difference signal is subjected to an analysis and to a time delay which corresponds to the time requirement for the analysis for updating the content of the image storage.