Method and apparatus for improving the picture quality in multi-dimensional differential pulse code modulation

Claim 1

A method for improving the picture quality in multidimensional DPCM coding of line scanned video signals comprising, the steps of computing at a transmitter an estimated signal value s at a present point from at least adjacent scanning signal values (B, C, D) in a preceding picture line which has previously been scanned and wherein one of the scanning signal values (D) is for a point after said present point, calculating at said transmitter an associated DPCM-value signal (Δs) from a current scanning signal value (X) for said present point and from said estimated signal value (s), and transmitting said associated DPCM-value signal (Δs), receiving said transmitted associated DPCM-value signal (Δs), calculating at a receiver said estimated signal values (s) and reconstructed scanning signal values (B r , C r , A r , X r . . . ) wherein during said calculation of said receiver estimated signal values (s) and said reconstructed scanning signal values, at least reconstructed signal values (B r , C r , D r ) for adjacent points in a preceding line and said associated DPCM-value signals (Δs) are used and for calculating a last reconstructed scanning signal value (X r ) of the picture line the associated DPCM-value signal (Δs) and at least said reconstructed adjacent scanning signal values (B r , C r ,) and an auxiliary scanning signal value (Hc) of the preceding picture line are used wherein said auxiliary scanning signal value (H c ) corresponds to a point after the end of each preceding picture line (AZ) and is occuring in a blanking gap, and wherein for said coding of corresponding line scanned video signals at the transmitter and for calculating and reconstructing the last scanning signal value (X r ) of the picture line at the receiver the same said auxiliary scanning values (H c ) are used.

Claim 2

A method for improving the picture quality in multidimensional DPCM coding of line scanned video signals comprising, the steps of computing at a transmitter an estimated signal value s at a present point from at least adjacent scanning signal values (B, C, D) in a preceding picture line which has previously been scanned and wherein one of the scanning signal values (D) is for a point after said present point, calculating at said transmitter an associated DPCM-value signal (Δs) from a current scanning signal value (X) for said present point and from said estimated signal value (s), and transmitting said associated DPCM-value signal (Δs), receiving said transmitted associated DPCM-value signal (Δs), calculating at a receiver said estimated signal values (s) and reconstructed scanning signal values (B r , C r , A r , X r . . . ) wherein during said calculation of said receiver estimated signal values (s) and said reconstructed scanning signal values, at least reconstructed signal values (B r , C r , D r ) for adjacent points in a preceding line and said associated DPCM-value signals (Δs) are used and for calculating a last reconstructed scanning signal value (X r ) of the picture line the associated DPCM-value signal (Δs) and at least said reconstructed adjacent scanning signal values (B r , C r ,) and an auxiliary scanning signal value (Hc) of the preceding picture line are used wherein said auxiliary scanning signal value (H c ) corresponds to a point after the end of each preceding picture line (AZ) and is occuring in a blanking gap, and wherein for said coding of corresponding line scanned video signals at the transmitter and for calculating and reconstructing the last scanning signal value (X r ) of the picture line at the receiver the same said auxiliary scanning values (H c ) are used.