Method of character recognition by linear traverse employing shifted edge lines

• US 3,899,771 A
• Filed: 06/17/1974
• Issued: 08/12/1975
• Est. Priority Date: 08/17/1971
• Status: Expired due to Term

• Current Assignee: Peter Roy Wavish, Peter Saraga
• Original Assignee: Peter Roy Wavish, Peter Saraga
• Inventors: Saraga, Peter, Wavish, Peter Roy
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US05/479,904
• Time in Patent Office: 421 Days
• Field of Search: 340/146.3AE,146.3AC,146.3R,146.3AQ,146.3MA
• US Class Current: 382/198
• CPC Class Codes: C08G 18/3887 Phosphite compounds
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/1823 using vector-coding

Abstract

A method of recognizing characters of varying stroke width by linear traverse is disclosed. A character is stored in a matrix of electrical storage cells with character cell positions distinguished from background cell positions by the presence of digital signals. A stored character is examined by using a predetermined group form (for example, a 2 X 2 square, a cruciform, a triangle or a 4 X 4 square) to sense for predetermined form characteristics (for example, two adjacent character cell positions of a 2 X 2 square) to generate a shifted edge line lying between character cell positions and adjacent background cell positions. The shifted edge line of the character defined by directional vectors is then compared with standard combinations in order to recognize the character.

Claims

1. A method of recognizing a character of varying stroke width comprising the steps of:

a. storing digital electrical signals identifying the shape of the character in a first matrix of storage cells whereby a character cell is distinguished from a background cell position by the presence of a digital signal;

b. sensing the digital signal characteristics of a predetermined group form of storage cells starting from a first predetermined group and sensing the condition of all cells within that group;

c. assigning for said sensed group of cells an appropriate operator, said operation being selected from a predetermined set of unique operators, said assigned operator establishing the center of said group and an associated vector direction for said group, said center being an interstitial point between cells of said group;

d. establishing the next group of cells whose digital information is to be sensed by employing the center and vector direction information of said first group of cells;

e. determining and storing in a second matrix a shifted edge line by repeated application of said sensing, assigning and establishing steps in a complete circuit of said character, said shifted line lying between the outermost character cell positions and adjacent background cell positions;

f. comparing said shifted edge line with a standard edge line in order to recognize the charActer.

2. A method as claimed in claim 1 wherein the form of said predetermined group form of storage cells is a 2 X 2 square block of cells, and either an operator having vector direction along the diagonal formed by two oppositely positioned background cells is selected when a group having one character cell and three background cells occurs or an operator is selected having a vector direction along the line through two character cells when a group having two adjacent character cells and two background cells occurs.

3. A method as claimed in claim 1, wherein the form of said predetermined group form of storage cells is a first triangle of six cell positions and said set of operators being chosen upon receipt of three cells which are arranged in a second triangle in a corresponding triangular orientation as said first triangle, said operators initially selectable upon first receiving indication of at least one character position and one background position within a triangle which does not form an edge of said first triangle, said operator being then selected for the assignment of an elementary edge vector originating in the center of said first triangle and being directed parallel to a line connecting two corresponding positions within said second triangle.

4. In a method for determining an edge of a character figure which is imaged on a two-dimensional pattern of positions arranged along rows and columns whereby a character position is distinguished from a background position by the presence of digital information, said method comprising the steps of;

sensing the information of a 2 X 2 block of positions;

applying said information to a number of operator-forming logical means;

generating by use of said operator-forming logical means upon reception of a single character position and three background positions an elementary edge vector along the diagonal formed by the two oppositely positioned background positions;

or generating by use of said operator-forming logical means upon reception of two adjacent character positions and two adjacent background positions an elementary edge vector along the line through said two character positions;

sensing and storing the output signals of said operator-forming logical means;

repeating all of the above steps for groups of cells along the edge of the character.

5. In a method for determining an edge of a character figure which is imaged on a two-dimensional pattern of positions arranged along rows and columns whereby a character position is distinguished from a background position by the presence of digital information, said method comprising the steps of:

sensing the information of twelve positions that are arranged according to a 4 X 4 matrix minus the four corner positions;

applying the information of a number of positions thereof which are arranged within a cross to one of a number of operator-forming logical means;

enabling said operator-forming logical means upon reception of a single first character position and two adjacent background positions within the three positions forming part of a central 2 X 2 block of said 4 X 4 matrix;

activating an enabled operator-forming logical means alternatively upon reception of three background positions lying in-line for generating an elementary edge vector along said line;

or activating an enabled operator-forming logical means upon reception of two further character positions within said cross for generating an elementary edge vector along two opposite positioned character positions within said cross;

or activating an enabled operator-forming logical means upon reception of a further character position and a further background position within said cross, the three background positions forming an L shape for generating an elementary edge vector along a connection line connecting the two character positions within said cross;

sensing and storing the output signals of said operator-forming logical means; and

repeating all of the above steps for groups of cells along the edge of the character.

6. In a method for determining an edge of a character figure which is imaged on a two-dimensional pattern of positions arranged along rows and columns whereby a character position is distinguished from a background position by the presence of digital information said method comprising the steps of:

sensing the information of a block of 4 X 4 positions, which are consecutively numbered from 1 to 16 along rows and columns, the value 1 being assigned to a character position and the value 0 to a background position;

applying the information of a number of positions within said block to one of a number of operatorforming logical means;

activating said operator-forming logical means for generating elementary edge vectors originating from the center of said block, said elementary edge vector being directed towards the position 1 if the function (1+5).2.3.6.7.(10+11) is '"'"''"'"''"'"''"'"'true,'"'"''"'"''"'"''"'"' said elementary edge vector being directed towards the center between positions 2 and 3 if the function (2+3).6.7.(10+11) is '"'"''"'"''"'"''"'"'true,'"'"''"'"''"'"''"'"' said elementary edge vector being directed towards the center between positions 2 and 3 if the function (2+6).3.4.7.8.(6+10).11.12 is '"'"''"'"''"'"''"'"'true,'"'"''"'"''"'"''"'"' said elementary edge vector having a zero length so that an isolated edge point is found if the function (2.3.4.6.7.8.10.11.12) is '"'"''"'"''"'"''"'"'true,'"'"''"'"''"'"''"'"' the other isolated edge points and elementary edge vectors being found by cyclic changing of the axis directions and the position information;

sensing and storing the output signals of said operator-forming logical means; and

repeating all of the above steps for groups of cells along the edge of the character.

7. In a method for determining an edge of a character figure which is imaged on a two-dimensional pattern of positions whereby a character is distinguished from a background position by the presence of digital information, said method comprising the steps of:

sensing the information of six positions that are arranged in a first triangle;

applying the information of three positions of said first triangle which are arranged according to second triangles, said second triangles being correspondingly oriented as said first triangle, to operator-forming logical means;

enabling said operator-forming logical means upon reception of at least one character position and one background position whithin a second triangle that does not form an edge of said first triangle, said enabled operator-forming logical means being operative for generating an elementary edge vector originating in the center of said first triangle and being directed parallel to a line connecting two corresponding positions within an enabling second triangle;

sensing and storing the output signals of said operator-forming logical means; and

repeating all of the above steps for groups of cells along the edge of the character.

8. A method as claimed in claim 2, wherein the total number in said set of unique operators is eight.

9. A method as claimed in claim 1, wherein the form of said predetermined group form of storage cells is a cruciform comprising a group of twelve storage cells arranged according to a 4 X 4 square block minus the four corner positions and said set of operators being selectable upon initially receiving indication of a single character cell position and two adjacent background cell positions within three cell positions forming part of a central 2 X 2 square block of said 4 X 4 matrix, said operators being selected upon receipt of either:

a. two further character cell positions within the cruciform for determining an elementary edge vector parallel to two oppositely positioned character cell positions within the cruciform, or b. a further character cell position and a further background cell position within the cruciform, the three background cell positions forming an L shape for determining an elementary edge vector parallel to a connection line connecting the two character cell positions within the cruciform;

or c. three background cell positions in a line for determining an elementary edge vector parallel to that line.

10. A method as claimed in claim 9 wherein the total number in said set of operators is 12.

11. A method as claimed in claim 3 wherein the total number in said set of operators is six.