Abstract: A facsimile scene typically includes a plurality of lines, each line having a plurality of picture elements (pels). Often, pel signals are adaptable for run-length coding, a run being one or more successive pels having the same brightness level. To increase the length of a run and hence to permit a more efficient use of a transmission link, a processor is disclosed for permuting a measure of the pel signals responsive to a reference signal. Illustratively, the reference signal is the pel signal from a previous line. In one exemplary bi-level pel signal embodiment, the measure is the current pel signal. Specifically, if the reference pel signal is a logic one, the current pel signal is loaded beginning at one end of a memory; if the reference pel signal is a logic zero, the current pel signal is loaded beginning at the other end of the memory. In a second embodiment, the measure is an error signal for indicating a difference between the reference signal and the current pel signal.

Abstract: A facsimile scene typically includes a plurality of lines, each line having a plurality of picture elements (pels). Often, pel signals are adaptable for run-length coding, a run being one or more successive pels having the same brightness level. To increase the length of a run and hence to permit more efficient use of a transmission link between transmitter and receiver, a processor arrangement is disclosed for permuting a measure of the pel signals responsive to a reference signal. The reference signal is a calibration signal. The measure is an error signal for indicating a difference between the current pel signal and a prediction thereof. In an illustrative bi-level facsimile system embodiment, if the calibration signal is a logic one, the error signal is loaded beginning at one end of a memory; if the calibration pel signal is a logic zero, the error signal is loaded beginning at the other end of the memory.

Abstract: In PCM and DPCM systems, a Hadamard orthogonal transformation of picture element signals is known to offer a means for reducing the bit rate for transmission of the signals. The first Hadamard coefficient, called H.sub.1, equals the sum of the picture element signals. Accordingly, still further reduction in the transmission bit rate can be achieved by efficiently coding H.sub.1. The disclosed coder includes a control signal generator for providing a control signal corresponding to a predetermined function of the quantized Hadamard coefficient signals. Several illustrative arrangements are disclosed. In three arrangements, the respective control signals are employed to adaptively select one of a plurality of quantizers, the selected quantizer for coding H.sub.1. In a fourth arrangement, the control signal is employed to predict H.sub.1, the predictor control signal being thereafter used for coding H.sub.1.