Data compression system

A method for generating the minimum amount of digital data representing a character comprising the steps of

• (a) scanning the character to generate an array of digital signals representative of the configuration of the character;
• (b) storing the digital signals in a first storage unit;
• (c) sensing the number of digital signals in the thickness of the character;
• (d) scanning the digital signals in the outer boundary of the configuration in said first storage unit;
• (e) transferring the digital signals sensed in a first portion of the outer boundary of the configuration of the character to a second storage unit;
• (f) storing in the second storage unit the digital signals representing the remaining portion of the outer boundary of the configuration by transposing the location of each digital signal in the remaining portion of the outer boundary along a horizontal plane equal to the thickness of the character in a direction toward said first portion of the outer boundary;
• (g) generating a plurality of coded vector representations representing the direction of line segments interconnecting the digital signals in the boundary of the configuration stored in said second storage unit;
• (h) determining the number of digital signals in the coded vector representations;
• (i) determining the number of digital signals in the configuration of the character stored in said second storage unit;
• (j) and selecting the least number of digital signals determined in steps (h) and (i).

A method of recording a character printed on a document comprising the steps of

• (a) scanning the character to derive an array of binary bits representative of the configuration of the character whereby a character binary bit is distinguished from a background bit;
• (b) storing the binary bits in a matrix of first storage areas;
• (c) sensing the binary bits of a predetermined group of said first storage areas starting from a storage area containing a first character binary bit located in the outer boundary of the character and sensing the binary bits in the remaining areas within the group to locate the next character binary bit in the boundary of the character;
• (d) sensing the number of character binary bits in the character at right angles to the character binary bit sensed in the outer boundary of the character to determine the thickness of the character;
• (e) counting each time a number of character bits in the thickness of the character is sensed;
• (f) repeating steps (c), (d) and (e) until all of the character binary bits in the outer boundary have been sensed and the thickness of the character sensed have been counted;
• (g) selecting the highest number thicknesses counted as the thickness of the character;
• (h) scanning the outer boundary of the character in said first storage areas;
• (i) storing the portions of the outer boundary scanned corresponding to the left-hand boundary of the character in a second storage area;
• (j) storing in said second storage area the remaining portion of the outer boundary scanned corresponding to the right-hand boundary of the character at a position derived by moving the character binary bits in the right-hand boundry of the character in a horizontal direction toward the left-hand boundary of the character a distance equal to the thickness of the character to produce the left-hand boundary of the character;
• (k) tracing the character binary bits in the outer boundary of the character stored in said second storage area;
• (l) assigning a coded vector representation representing the direction between each of the character binary bits in the boundary traced;
• (m) generating a first binary value equal to the number of binary bits in the coded vector representations;
• (n) generating a second binary value equal to the number of binary bits in the character configuration stored in said second storage area;
• (o) comparing said first and second binary values to indicate the least number of binary bits generated in steps (n) and (o) on a recording medium;
• (p) and recording on a recording medium the binary bits indicated in step (o) as being the least number of binary bits representing the character printed on the document.

In a pattern recognition system having means for digitizing an analog pattern digital bits and background digital bits, means for determining the minimum amount of data describing the pattern comprising

• (a) means for storing pattern digital bits representing a character;
• (b) means for forming vector representation of line segments connecting adjacent pattern digital bits in the boundary of the character stored in said storage means;
• (c) means for adding the number of digital bits in said vector representation to produce a first digita value;
• (d) means for multiplying the number of digital bits in the height and width of the character to produce a second digital value;
• (e) and means for comparing said first and second digital values for indicating the minimum amount of digital bits between the vector representation and the pattern and background digital bits.