METHOD OF MODIFYING CLASSIFICATION SCHEME FOR HAND-WRITTEN CHARACTERS

• US 20110110593A1
• Filed: 01/12/2011
• Published: 05/12/2011
• Est. Priority Date: 10/15/2001
• Status: Active Grant

• Current Assignee: Silverbrook Research Pty Limited
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Napper, Jonathon Leigh
• Granted Patent: US 8,019,160 B2
• Time in Patent Office: Days
• US Class Current: 382/186
• CPC Class Codes: G06V 30/244 using graphical properties, e.g. alphabet type or font

Abstract

A method of modifying a classification scheme for classifying hand-written characters. The method includes the steps of: receiving digital ink representing a handwritten character from an optically imaging pen; determining a selection value based on the similarity of the received character and a respective prototype vector of the stored classification scheme; selecting a prototype vector of the stored classification scheme in accordance with the determined selection value; selecting a class of the stored classification scheme in accordance with a selected prototype representing the character; selecting a stored user dependent weighted allograph in accordance with the selected prototype vector representing the character; modifying an allograph in the respective class; and storing a modified classification scheme which includes the modified allograph.

Claims

1. A method of modifying a classification scheme for classifying hand-written characters, said method comprising the steps of:

storing the classification scheme in a memory, said classification scheme including a plurality of classes and user dependent weighted allographs, each class representing a respective letter and containing one or more of the allographs, each allograph including an associated weighting and representing a respective style of a respective letter and containing one or more prototypes, each prototype representing a variation in the respective allograph and being represented as a prototype vector, each prototype vector being formed from a number of values, each value quantifying a respective feature of the respective prototype vector;

receiving digital ink representing at least one handwritten character from an optically imaging pen;

determining a selection value based on the similarity of the received character and a respective prototype vector of the stored classification scheme;

selecting a respective one of the prototype vectors of the stored classification scheme in accordance with the determined selection value;

selecting a class of the stored classification scheme in accordance with a selected prototype representing the character to thereby determine a letter represented by the character;

selecting a stored user dependent weighted allograph in accordance with the selected prototype vector representing the character;

modifying one or more of the allographs in the respective class in accordance with the selection by modifying the weighting of said one or more of the allographs; and

storing a modified classification scheme which includes said modified allographs.

2. The method according to claim 1, further comprising the steps of:

determining a feature vector representing the character, the feature vector being formed from a number of values, each value quantifying a respective feature of the character; and

determining a distance value representing the distance between the determined feature vector and the respective prototype vector.

3. The method according to claim 1, wherein the selection value is determined in accordance with the determined distance value and the weighting associated with the respective allograph.

4. The method according to claim 1, wherein the weightings are modified by at least one of:

decreasing the weighting for the allograph containing the selected prototype; and

,

increasing the weighting for one or more of the allographs that do not contain the selected prototype.

5. The method according to claim 1, further comprising the steps of:

selecting a reference prototype for each allograph to be modified;

determining the distance value for each reference prototype;

determining an average of the determined distance values; and

,

modifying the weighting of each allograph in accordance with the distance value of the respective reference prototype and the average distance value.

6. The method according to claim 5, wherein the reference prototype is selected on the basis of being the prototype having the lowest distance value for the respective allograph.