Arrangement for two-dimensional DPCM coding

DETAILED DESCRIPTION It is therefore an object of the present invention to provide an arrangement for DPCM coding/decoding which can be realized in a simple manner.
The above object is achieved in that a plurality of registers connected in series are provided, the picture element values of the television line which are adjacent to the processing picture element signal being stored in these registers.
The quantizer controller contains a comparison device which executes an amplitude comparison between the picture element signal values of the preceding television line.
A selection control is connected to the outputs of the comparison device.
A peak value control is provided which through-connects two peak values of the picture element signal values to a subtraction device via a multiplex device, the most recently-calculated picture element signal value also being supplied to the subtraction device and the difference between the most recently-calculated picture element signal value and the peak values, as well as between the peak values being formed therein.
A difference selection control to which the operational sign bit of the differences are supplied is provided.
A multiplexer is connected to the outputs of the subtraction device, the difference selection control through-connecting the highest, amount-wise, difference via the multiplexer to a threshold logic which controls the quantizer.
The assessed value x must be determined in the coder.
In order for the decoder to be able to execute the same calculation as the coder, the assessed value may not be determined from the original picture element signal values, but only from the picture element signal values from the so-called local output which have already been calculated in the coder.
The highest and the lowest picture element values, the extrema, are first identified in the coder from the picture element signal values of the preceding line.
Only simple comparators and the multiplexer are required for this purpose.
The computational operation with the last picture element signal value A is always time-critical