Handwriting recognition system

• US 7,054,510 B1
• Filed: 03/21/2000
• Issued: 05/30/2006
• Est. Priority Date: 03/24/1999
• Status: Expired due to Fees

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Milner, Benjamin P
• Primary Examiner(s): Ahmed, Samir
• Assistant Examiner(s): LE, BRIAN Q
• Application Number:
  US09/914,262
• Time in Patent Office: 2,261 Days
• Field of Search: 382/119, 382/120, 382/121, 382/122, 382/123, 382/187, 382/188, 382/189
• US Class Current: 382/313
• CPC Class Codes: G06V 30/1423 the instrument generating sequences of position coordinates corresponding to handwriting preprocessing or recognising digital ink G06V30/32

Abstract

In order to improve the accuracy of recognition of hand-written input using a stylus, output signals from a plurality of accelerometers representing x and y axis acceleration and deceleration are sampled at a predetermined rate and passed through a digital bandpass filter to remove high frequency components and dc components arising from gravity. X and y vectors derived from the original x and y input signals are passed to a classifier using a hidden Markov model. Bandpass filtering improves the robustness of the interpretation of the vectors against stored templates which may be templates of individual characterizations or of whole words.

Claims

1. A method of analyzing signals from a moving handheld device, the method comprising:

sampling signals at a predetermined rate,

passing signals through a bandpass filter to remove dc level and high frequency components,

sampling the filtered output to provide a series of vectors representing the position of the handheld device at periodic intervals; and

using a classifier to compare the sample sets with predetermined templates to determine the character for output.