Method for transmitting a facsimile signal by sequential edge differential coding

Claim 1

A method for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture being of a first level or a second level of optical character, said method comprising the steps of: scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; progressively storing said scan data of each successive line as current line information to be coded, and said scan data of the immediately preceding scanned line as preceding line information; simultaneously accessing corresponding said stored current line information and said stored preceding line information to determine, for each of said current line and said preceding line, the presence of transitions in said optical character between adjacent ones of said successively scanned picture elements; identifying, for each successive two of said determined transitions in said current line information and preceding line information, whether said transitions are of: a. a First state in which the two transition points exist on the preceding line and the current line, respectively, b. a Second state in which the two transition points exist only on the preceding line, and c. a Third state in which the two transition points exist only on the current line; measuring: d. as to each First state, only the number of picture elements between the locations of the two transition points on the preceding line and the current line, and the direction of the difference, and e. as to each Third state, the first distance between the second transition point in the state immediately preceding the Third state and the first transition point in the Third stage, and the second distance between the first transition point in the Third state and the second transition point in the Third state; and generating digital outputs respectively comprising: f. in the First stage, a signal indicating the number of picture elements measured in step d., and identifying the First state, g. in the Second state, a signal identifying the Second state, and h. in the Third state, a signal indicating the first and second distances, and identifying the Third state.

Claim 2

A method for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture being of a first level or a second level of optical character, said method comprising the steps of: scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; progressively storing said scan data of each successive line as current line information to be coded, and said scan data of the immediately preceding scanned line as preceding line information; simultaneously accessing corresponding said stored current line information and said stored preceding line information to determine, for each of said current line and said preceding line, the presence of transitions in said optical character between adjacent ones of said successively scanned picture elements; identifying, for each successive two of said determined transitions in said current line information and preceding line information, whether said transitions are of: a. a First state in which the two transition points exist on the preceding line and the current line, respectively, b. a Second state in which the two transition points exist only on the preceding line, and c. a Third state in which the two transition points exist only on the current line; measuring: d. as to each First state, only the number of picture elements between the locations of the two transition points on the preceding line and the current line, and the direction of the difference, and e. as to each Third state, the first distance between the second transition point in the state immediately preceding the Third state and the first transition point in the Third stage, and the second distance between the first transition point in the Third state and the second transition point in the Third state; and generating digital outputs respectively comprising: f. in the First stage, a signal indicating the number of picture elements measured in step d., and identifying the First state, g. in the Second state, a signal identifying the Second state, and h. in the Third state, a signal indicating the first and second distances, and identifying the Third state.

Claim 7

A method for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture element being of a first level or a second level of optical character, said method comprising the steps of: scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; progressively storing said scan data of each successive line as current line information to be coded, and said scan data of the immediately preceding scanned line as preceding line information; simultaneously accessing corresponding said stored current line information and said stored preceding line information to determine, for each of said current line and said preceding line, the presence of transitions in said optical character between adjacent ones of said successively scanned picture elements; identifying, for each successive two of said determined transitions in said current line information and preceding line information, whether said transitions are of: a. a First state in which the two transition points exist on the preceding line and the current line, respectively, b. a Second state in which the two transition points exist only on the preceding line, and c. a Third state in which the two transition points exist only on the current line; measuring: d. as to each First state, only the number of picture elements between the locations of the two transition points on the preceding line and the current line, and the direction of the difference, and e. as to each Third state, the first distance between the second transition point in the state immediately preceding the Third state and the first transition point in the Third state, and the second distance between the first transition point in the Third state and the second transition point in the Third state; and generating digital outputs respectively comprising: f. in the First state, a signal indicating the number of picture elements measured in step d., and identifying the First state, g. in the Second state, a signal identifying the Second state, and h. in the Third state, a signal indicating the first and second distances, and identifying the Third state; said method further comprising the steps of detecting whether or not the second transition point occurs at the same location on the current line and the preceding line after the first transition point occurs on one of the preceding line and the current line, and establishing a state identification priority for each of the First, Second and Third states in anticipation of the case where the second transition point occurs at the same location on the both scan lines; said method including the additional steps of subdividing the scan lines, each represented by binary picture elements having one of said first and second levels, into predetermined segments; generating a first control code for detecting errors immediately before coding of each scan segment; generating a self-synchronized second control code for recovery from an error state immediately before coding of every K (K=1, 2, 3, . . . ) scan lines; and coding the first scan segment of every K scan lines using only picture signal information of the scan segment without using picture signal information of the preceding scan line.

Claim 8

A method for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture element being of a first level or a second level of optical character, said method comprising the steps of: scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; progressively storing said scan data of each successive line as current line information to be coded, and said scan data of the immediately preceding scanned line as preceding line information; simultaneously accessing corresponding said stored current line information and said stored preceding line information to determine, for each of said current line and said preceding line, the presence of transitions in said optical character between adjacent ones of said successively scanned picture elements; identifying, for each successive two of said determined transitions in said current line information and preceding line information, whether said transitions are of: a. a First state in which the two transition points exist on the preceding line and the current line, respectively, b. a Second state in which the two transition points exist only on the preceding line, and c. a Third state in which the two transition points exist only on the current line; measuring: d. as to each First state, only the number of picture elements between the locations of the two transition points on the preceding line and the current line, and the direction of the difference, and e. as to each Third state, the first distance between the second transition point in the state immediately preceding the Third state and the first transition point in the Third state, and the second distance between the first transition point in the Third state and the second transition point in the Third state; and generating digital outputs respectively comprising: f. in the First state, a signal indicating the number of picture elements measured in step d., and identifying the First state, g. in the Second state, a signal identifying the Second state, and h. in the Third state, a signal indicating the first and second distances, and identifying the Third state; said method further comprising the steps of detecting whether or not the second transition point occurs at the same location on the current line and the preceding line after the first transition point occurs on one of the preceding line and the current line, and establishing a state identification priority for each of the First, Second and Third states in anticipation of the case where the second transition point occurs at the same location on the both scan lines; said method including the additional steps of subdividing the scan lines, each represented by binary picture elements having one of said first and second levels, into predetermined segments; generating a first control code for detecting errors immediately before coding of each scan segment; generating a self-synchronized second control code for recovery from an error state immediately before coding of every K (K=1, 2, 3, . . . ) scan lines; and coding the first scan segment of every K scan lines using only picture signal information of the scan segment without using picture signal information of the preceding scan line.

Claim 9

An apparatus for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture element being of a first level or a second level of optical character, said apparatus comprising: means for scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; first line memory means for storing said scan data of said preceding line, the latter scan data including transition points between said first level and said second level adjacent to said current line to be coded, and which scan data comprise a two-level signal; second line memory means for storing said scan data of the current line to be coded, the latter also including transition points between said first level and said second level adjacent to said preceding line, and which scan data also comprise a two-level signal; mode data developing means responsive to said scan data from said first and second line memory means, and to said transition points included therein, for developing successive mode data representing the combined optical character of corresponding picture elements from said preceding line and said current line; mode comparator means for comparing each successive mode data developed by said mode data developing means with the immediately preceding mode data developed by said mode data developing means so as to detect transitions therebetween; state identification logic means for indicating a first state when two transition points occur successively along said scan line of said current line and said scan line of said preceding line, respectively, a second state when said successively occurring two transition points occur only on said preceding line, and a third state when said successively occurring two transition points occur only on said current line; run-length counter means for counting the number of picture elements having the same mode data until a picture element of a different mode data is encountered to develop a first count value, and for counting the number of picture elements from the second of said successively occurring two transition points for the preceding mode data to the first of said successively occurring two transition points for the current mode data to develop a second count value; state code generator means for generating state codes indicating the indentification of said second and third states, respectively; polarity code generator means for generating, upon identification of said first state, one of a plus, minus or zero code in accordance with whether said transition point of said preceding line respectively precedes, coincides with, or succeeds corresponding said transition point of said current line; difference code generator means for converting, in the case of identification of said first state, the second count value of said run-length counter means into a difference code; and run-length code generator means for sequentially converting, in the case of identification of said third state, the first count value of said run-length counter means into a run-length code; wherein said mode data developing means comprises: a first mode register connected to both said first and second line memory means for receiving successive, combined outputs of said first and second line memory means, said successive combined outputs identifying the combined optical character of successive, corresponding picture elements of said preceding and current lines, said first mode register providing, as its own output, each successive combined output of said first and second line memory means; and a second mode register connected to said output of said first mode register for receiving each successively provided combined output of said first and second line memory means; said mode comparator means being connected to said first and second mode registers for comparing each combined output sequentially provided by said first and second line memory means to said first mode register with the immediately preceding sequentially provided combined output of said first and second line memory means as held by said second mode register.

Claim 10

An apparatus for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture element being of a first level or a second level of optical character, said apparatus comprising: means for scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; first line memory means for storing said scan data of said preceding line, the latter scan data including transition points between said first level and said second level adjacent to said current line to be coded, and which scan data comprise a two-level signal; second line memory means for storing said scan data of the current line to be coded, the latter also including transition points between said first level and said second level adjacent to said preceding line, and which scan data also comprise a two-level signal; mode data developing means responsive to said scan data from said first and second line memory means, and to said transition points included therein, for developing successive mode data representing the combined optical character of corresponding picture elements from said preceding line and said current line; mode comparator means for comparing each successive mode data developed by said mode data developing means with the immediately preceding mode data developed by said mode data developing means so as to detect transitions therebetween; state identification logic means for indicating a first state when two transition points occur successively along said scan line of said current line and said scan line of said preceding line, respectively, a second state when said successively occurring two transition points occur only on said preceding line, and a third state when said successively occurring two transition points occur only on said current line; run-length counter means for counting the number of picture elements having the same mode data until a picture element of a different mode data is encountered to develop a first count value, and for counting the number of picture elements from the second of said successively occurring two transition points for the preceding mode data to the first of said successively occurring two transition points for the current mode data to develop a second count value; state code generator means for generating state codes indicating the indentification of said second and third states, respectively; polarity code generator means for generating, upon identification of said first state, one of a plus, minus or zero code in accordance with whether said transition point of said preceding line respectively precedes, coincides with, or succeeds corresponding said transition point of said current line; difference code generator means for converting, in the case of identification of said first state, the second count value of said run-length counter means into a difference code; and run-length code generator means for sequentially converting, in the case of identification of said third state, the first count value of said run-length counter means into a run-length code; wherein said mode data developing means comprises: a first mode register connected to both said first and second line memory means for receiving successive, combined outputs of said first and second line memory means, said successive combined outputs identifying the combined optical character of successive, corresponding picture elements of said preceding and current lines, said first mode register providing, as its own output, each successive combined output of said first and second line memory means; and a second mode register connected to said output of said first mode register for receiving each successively provided combined output of said first and second line memory means; said mode comparator means being connected to said first and second mode registers for comparing each combined output sequentially provided by said first and second line memory means to said first mode register with the immediately preceding sequentially provided combined output of said first and second line memory means as held by said second mode register.

Claim 12

An apparatus for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture element being of a first level or a second level of optical character, said apparatus comprising: means for scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; means for progressively storing said scan data of each successive line as current line information to be coded, and said scan data of the immediately preceding scanned line as preceding line information; means for simultaneously accessing corresponding said stored current line information and said stored preceding line information to determine, for each of said current line and said preceding line, the presence of transitions in said optical character between adjacent ones of said successively scanned picture elements; means for identifying: a first state in response to the two transition points existing on the preceding line and the current line, respectively, a second state in response to the two transition points existing only on the preceding line, and a third state in response to the two transition points existing only on the current line; means for measuring: as to each first state, only the number of picture elements between the locations of the two transition points on the preceding line and the current line, respectively, and the direction of the difference, and as to each third state, the first distance between the second transition point in the state immediately preceding the third state and the first transition point in the third state, and the second distance between the first transition point in the third state and the second transition point in the third state; and means for generating digital outputs respectively comprising: in the first state, a signal indicating the number of picture elements measured as to each first state, and identifying the first state, in the second state, a signal identifying the second state, and in the third state, a signal indicating the first and second distances, and identifying the third state.

Claim 13

An apparatus for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture element being of a first level or a second level of optical character, said apparatus comprising: means for scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; means for progressively storing said scan data of each successive line as current line information to be coded, and said scan data of the immediately preceding scanned line as preceding line information; means for simultaneously accessing corresponding said stored current line information and said stored preceding line information to determine, for each of said current line and said preceding line, the presence of transitions in said optical character between adjacent ones of said successively scanned picture elements; means for identifying: a first state in response to the two transition points existing on the preceding line and the current line, respectively, a second state in response to the two transition points existing only on the preceding line, and a third state in response to the two transition points existing only on the current line; means for measuring: as to each first state, only the number of picture elements between the locations of the two transition points on the preceding line and the current line, respectively, and the direction of the difference, and as to each third state, the first distance between the second transition point in the state immediately preceding the third state and the first transition point in the third state, and the second distance between the first transition point in the third state and the second transition point in the third state; and means for generating digital outputs respectively comprising: in the first state, a signal indicating the number of picture elements measured as to each first state, and identifying the first state, in the second state, a signal identifying the second state, and in the third state, a signal indicating the first and second distances, and identifying the third state.

Claim 21

An apparatus for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture element being of a first level or a second level of optical character, said apparatus comprising: means for scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; means for progressively storing said scan data of each successive line as current line information to be coded, and said scan data of the immediately preceding scanned line as preceding line information; means for simultaneously accessing corresponding said stored current line information and said stored preceding line information to determine, for each of said current line and said preceding line, the presence of transitions in said optical character between adjacent ones of said successively scanned picture elements; means for identifying: a first state in response to the two transition points existing on the preceding line and the current line, respectively, a second state in response to the two transition points existing only on the preceding line, and a third state in response to the two transition points existing only on the current line; means for measuring: as to each first state, only the number of picture elements between locations of the two transition points on the preceding line and the current line, respectively, and the direction of the difference, and as to each third state, the first distance between the second transition point in the state immediately preceding the third state and the first transition point in the third state, and the second distance between the first transition point in the third state and the second transition point in the third state; and means for generating digital outputs respectively comprising: in the first state, a signal indicating the number of picture elements measured as to each first state, and identifying the first state, in the second state, a signal identifying the second state, and in the third state, a signal indicating the first and second distances, and identifying the third state; said system further comprising: means for detecting whether or not the second transition point occurs at the same location on the current preceding line after the first transition point occurs on one of the preceding line and the current line, and means for establishing a state identification priority for each of the first, second and third states in anticipation of the case where the second transition point occurs at the same location on both scan lines; means for subdividing the scan lines, each represented by binary picture elements having one of said first and second levels, into predetermined segments; means for generating a first control code for detecting errors immediately before coding of each scan segment; means for generating a self-synchronized second control code for recovery from an error state immediately before coding of every K (K=1, 2, 3, . . . ) scan lines; and means for coding the first scan segment of every K scan lines using only picture signal information of the scan segment without using picture signal information of the preceding scan line.

Claim 22

An apparatus for developing a facsimile signal for transmission by sequential edge differential coding of picture information contained on a document, said picture information corresponding to a plurality of picture elements grouped into successive lines on said document, each picture element being of a first level or a second level of optical character, said apparatus comprising: means for scanning successive said picture elements along each of said successive lines to generate scan data representing said optical character of said picture elements; means for progressively storing said scan data of each successive line as current line information to be coded, and said scan data of the immediately preceding scanned line as preceding line information; means for simultaneously accessing corresponding said stored current line information and said stored preceding line information to determine, for each of said current line and said preceding line, the presence of transitions in said optical character between adjacent ones of said successively scanned picture elements; means for identifying: a first state in response to the two transition points existing on the preceding line and the current line, respectively, a second state in response to the two transition points existing only on the preceding line, and a third state in response to the two transition points existing only on the current line; means for measuring: as to each first state, only the number of picture elements between locations of the two transition points on the preceding line and the current line, respectively, and the direction of the difference, and as to each third state, the first distance between the second transition point in the state immediately preceding the third state and the first transition point in the third state, and the second distance between the first transition point in the third state and the second transition point in the third state; and means for generating digital outputs respectively comprising: in the first state, a signal indicating the number of picture elements measured as to each first state, and identifying the first state, in the second state, a signal identifying the second state, and in the third state, a signal indicating the first and second distances, and identifying the third state; said system further comprising: means for detecting whether or not the second transition point occurs at the same location on the current preceding line after the first transition point occurs on one of the preceding line and the current line, and means for establishing a state identification priority for each of the first, second and third states in anticipation of the case where the second transition point occurs at the same location on both scan lines; means for subdividing the scan lines, each represented by binary picture elements having one of said first and second levels, into predetermined segments; means for generating a first control code for detecting errors immediately before coding of each scan segment; means for generating a self-synchronized second control code for recovery from an error state immediately before coding of every K (K=1, 2, 3, . . . ) scan lines; and means for coding the first scan segment of every K scan lines using only picture signal information of the scan segment without using picture signal information of the preceding scan line.