Method and arrangement for storing or transmitting and for recovering image signals

摘要

During the transformation coding of images, an increase in the range of values of the coefficients generated during this process is produced by the arithmetic operation on the image signals. To reduce or completely to eliminate this increase, the possible range of values of the coefficients is determined as a function of the preceding coefficients and the quantising characteristic is set accordingly. For this purpose, it is only necessary to store the maximum value of the preceding coefficients or the minimum difference between the preceding coefficients and half the maximum value range and, as a function of this, to switch over the characteristics memory which controls the quantiser. During the decoding, the characteristic of the decoder is correspondingly switched over as a function of the previously decoded coefficients.