Document security system

A method of storing an encoded signal representative of a signature of a user onto a magnetic stripe on a document, the method comprising the steps of:

• digitising the user's signature;
• compressing the digitised signature to 160 bytes or less by setting an image size of the signature, and setting a level of digital data to fit into said image size;
• scanning the digitised signature line by line;
• on the first scan line removing multiple dots and storing a number of dots and a number of dot displacements;
• on the second and subsequent scan lines, for each stored dot on the previous line, counting and storing increment values, and counting and storing the number and position of stray dots;
• comparing a total dot count in the compressed digital data with the level of digital data;
• scaling the image size of the signature by the dot count in the vertical and horizontal directions;
• repeating the method steps until the compressed digital data is less than the set level of digital data;
• and magnetically recording the compressed signature onto the document so that it cannot be read directly by the unaided eye.

A method of compressing a digitised image of a signature, comprising the steps of:

• setting an image size of the signature, setting a level of digital data to fit into said image size;
• scanning the digitised image of the signature line by line;
• on a first scan line removing multiple dots and storing a number of dots and a number of dot displacements;
• on a second and subsequent scan lines for each dot on the previous line counting and storing increment values, and counting and storing the number and position of stray dots;
• comparing a total dot count in the compressed digitised signature with the digital data level;
• scaling the image size of the signature by a target/dot count in the vertical and horizontal directions;
• and
• repeating the method steps until the compressed digital signature is less than the set level of digital data.