Method and apparatus for aggressive compression, storage and verification of the dynamics of handwritten signature signals
First Claim
1. In a system that captures handwriting on a digitizer tablet, a method performed by a processor for generating and storing data representing the handwriting comprising:
- said processor processing the captured handwriting to identify strokes of the handwriting;
said processor partitioning each stroke into a plurality of segments;
said processor generating a plurality of parameters for each segment;
said processor generating a compressed representation for each given segment by transforming the parameters for the given segment;
said processor generating data representing the handwriting based upon the compressed representation for each given segment; and
said processor storing the data representing the handwriting.
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Accused Products
Abstract
The fields of biometrics and commerce can benefit from the aggressive compression techniques presented here. A novel approach to compressing the on-line handwriting signal without losing the dynamic information (i.e., velocity and order) is presented which provides the means to fit almost any signature sample within the 57-byte limit of one of the free magnetic strips on the back of conventional transaction cards such as credit or debit cards or other identity cards. The apparatus requires an on-line signature capture tablet capable of sampling the handwritten signature in a series of sampled X and Y coordinates. The compression method starts with segmenting the on-line handwriting signal into portions which may be approximated with a set of features from which the velocity and position may be reconstructed. These features are then compressed further using standard compression techniques. A Huffman coding technique is used to demonstrate this step. The size of the average signature including its dynamic information is stored in a space less than 57 bytes which is the magic limit imposed by conventional, magnetic transaction (credit or debit) card strips. This is by far less than about 1000 bytes required if only loss-less techniques were used. A loss-less compression technique is also briefly presented. Normally, out of the three strips which are provided on the back of a card, two strips are available and may be used for storing the template of the owner'"'"'s signature for future verification.
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Citations
23 Claims
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1. In a system that captures handwriting on a digitizer tablet, a method performed by a processor for generating and storing data representing the handwriting comprising:
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said processor processing the captured handwriting to identify strokes of the handwriting; said processor partitioning each stroke into a plurality of segments; said processor generating a plurality of parameters for each segment; said processor generating a compressed representation for each given segment by transforming the parameters for the given segment; said processor generating data representing the handwriting based upon the compressed representation for each given segment; and said processor storing the data representing the handwriting. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification