Digital encoder for facsimile transmission

Claim 1

ENCODING APPARATUS FOR IMAGE SIGNALS WHICH COMPRISES A SOURCE OF ANALOG IMAGE SIGNALS, MEANS FOR GENERATING THRESHOLD FUNCTION SIGNALS, NETWORK MEANS SUPPLIED WITH SAID THRESHOLD FUNCTION SIGNALS AND WITH SAID IMAGE SIGNALS FOR ALGEBRAICALLY COMBINING SAID FUNCTION SIGNALS AND SAID IMAGE SIGNALS, NETWORK MEANS INCLUDING AMPLITUDE THRESHOLD MEANS FOR EVALUATING THE AMPLITUDE OF SAID COMBINED SIGNALS IN TERMS OF A PRESCRIBED THRESHOLD, NETWORK MEANS RESPONSIVE TO SAID EVALUATION FOR DEVELOPING SIGNALS OF A FIRST BINARY STATE FOR COMBINED SIGNAL LEVELS ABOVE SAID PRESCRIBED THRESHOLD AND SIGNALS OF A SECOND BINARY STATE FOR COMBINED SIGNALS LEVELS BELOW SAID PRESCRIBED THRESHOLD, AND MEANS FOR COORDINATING THE GENERATION OF SAID THRESHOLD FUNCTION SIGNALS AND THE DEVELOPMENT OF SAID BINARY SIGNALS.

Claim 3

THE METHOD OF DEVELOPING A BINARY SIGNAL REPRESENTATIVE TO AN IMAGE SCENE THAT MAY BE USED TO DEVELOP A MULTISHADE REPRODUCTION OF THE SCENE WHICH INCLUDES THE STEPS OF DEVELOPING ANALOG SIGNALS REPRESENTATIVE OF AN IMAGE SCENE, ESTABLISHING A THRESHOLD BETWEEN TWO DISCRETE IMAGE SIGNAL LEVELS, CARRYING THE THRESHOLD ACCORDING TO A PRESCRIBED SCHEDULE, UTILIZING THE SCHEDULED THRESHOLD TO ESTABLISH TWO SIGNAL LEVEL REGIONS, AND DEVELOPING BINARY SIGNAL REPRESENTATIONS OF THE TWO SIGNAL REGIONS ON A FUNCTION OF TIME.

Claim 4

THE METHOD OF DEVELOPING A BINARY SIGNAL REPRESENTATIVE TO AN IMAGE SCENE THAT MAY BE USED TO DEVELOP A MULTISHADE REPRODUCTION OF THE SCENE WHICH INCLUDES THE STEPS OF DEVELOPING ANALOG SIGNALS REPRESENTATIVE OF AN IMAGE SCENE, ESTABLISHING A THRESHOLD BETWEEN TWO DISCRETE IMAGE SIGNAL LEVELS, CARRYING THE THRESHOLD ACCORDING TO A PRESCRIBED SCHEDULE, UTILIZING THE SCHEDULED THRESHOLD TO ESTABLISH TWO SIGNAL LEVEL REGIONS, AND DEVELOPING BINARY SIGNAL REPRESENTATIONS OF THE TWO SIGNAL REGIONS ON A FUNCTION OF TIME.