Data compression

In a system for processing video signals for purposes of compression, the combination comprising:

• first means for converting the video signals into a train of bi-valued bits wherein bits of a first value represent white or light image increments and bits of the opposite value represent black or dark image increments;
• second means connected to the first means and counting the number of continuous bits of the same value and providing a stream of count numbers, separately in two channels for counted bits of opposite values, so that the numbers follow in a continuous sequence in the two channels and distinguish alternatingly in the two channels;
• and
• third means connected to receive the bits of the two channels and converting them in a stream of symbols using at least one bit per channel in parallel for generating representation of the symbols.

In a system for transmitting data in compressed format and which includes a pick-up to provide a train of two level signals and a reproduction unit operating in response to a train of control signals to obtain reproduction of the two level signal, further having a transmitter for transmitting modulated carrier signals and a receiver for receiving such signals;

• comprising:
• first means for converting the two level signals into a sequence of run length numbers represented by a train of ternary digits;
• second means connected for converting the train of ternary digits into a stream of symbols represented by electrical signals permitting distinction among plural symbols wherein one or two consecutive ternary digits appear as one distinct symbol in the stream depending on the value of the digit or digits;
• third means for causing the transmitter to transmit the symbols to be received by the receiver;
• fourth means for converting a stream of received symbols into a train of ternary digits;
• and
• sixth means for interpreting the train of ternary digits as provided by the fifth means as a sequence of run length numbers and providing a sequence of control signals for obtaining said reproduction of the two level signal.

A system for compressing data represented by or converted into a stream of two level signals, where signal portions of the first level are followed respectively by signals of a second level and vice versa, comprising:

• first means for alternatingly counting the length of runs of signal portions of the two levels as they are alternatingly presented and setting the count numbers arrived at by counting run length of signals of the first level into a first channel and setting count numbers arrived at by counting run length of signals of the second level into a second channel, respectively with zero bits being set into the second and first channels accompanying each count bit in the first and second channels;
• second means connected to the first means for processing bit pairs as presented concurrently in the first and second channels to obtain modulation control signals, distinguishing among different modulations in excess of two to modulate a carrier frequency accordingly;
• and
• means for transmitting the modulated carrier.

A system for compressing data represented by or converted into a stream of two level signals, where signal portions of the first level and vice versa, comprising:

• first means for alternatingly counting the length of runs of signal portions of the two levels as they are alternatingly presented and setting the count numbers arrived at by counting run length of signals of the first level into a first channel and setting count numbers arrived at by counting run length of signals of the second level into a second channel, respectively with zero bits being set into the second and first channels accompanying each count bit in the first and second channels;
• buffer means including a first pair and a second pair of registers connected alternatingly to the first and to the second channel so that the registers of each pair respectively receive said count numbers in alternating sequence as to the first and second pair;
• storage means alternatingly connected to the second and first pair of registers for extracting therefrom the bits as respectively previously received from the first means for temporarily storing these signals;
• and
• circuit means connected to the storage means and obtaining retrieval of said bits and causing them to be transmitted.

A system for transmitting data developed as two level source data wherein runs of a first signal level are respectively followed by runs of a second signal level and necessarily vice versa, comprising:

• counting means for counting the lengths of said runs and providing the count numbers in sequence of ternary bits for identifying therewith each number as to the type of level it represents as to length of a run thereof;
• modulating means connected to receive said ternary bits and phase modulate a carrier on a seven level basis, six phases plus off, in accordance with groups of one or two consecutive bits;
• means for transmitting the said modulated carrier;
• means for receiving the said transmitted modulated carrier;
• demodulating means responsive to the received transmitted modulated carrier and including first circuit means particularly responsive to particular ones of the phase modulations to provide plural outputs differing in amplitude from the different phase modulations, further including several circuit means responsive to said plural outputs to provide demodulation outputs depending on the combination in values of the plural outputs;
• and
• means responsive to the demodulation outputs to reconstruct said two level data.

In a system for transmitting facsimile signals comprising:

• first means for generating a stream of digits defining the lengths of consecutively scanned runs of white and runs of black as detected in alternating sequence, and providing such digits at a variable rate;
• second means connected to the first means and being responsive to particular values of digits individually and of the values of digits of groups of digits in said stream as generated by the first means, and including means (a) for providing signals representing distinguishable symbols as representing individual groups of digits of particular values and individual digits for at least one value thereof and including means (b) to provide a stream of symbols at a constant rate, wherein at least one of the symbols represents a digit of particular value and other symbols represent groups of digits of particular value combinations, so that the symbols as provided at a constant rate represent a digit flow at a variable rate;
• and
• third means connected to the second means for transmitting the symbols at the constant symbol rate.