Patent EP0442208A2 successfully refreshed from Google Patents.
EP0442208A2
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EP
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A device and method for verifying personal handwriting
Assignee: BTG International Ltd
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Filing: 1990-12-12
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Granted: —
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Expires: 2010-12-12
Abstract
Abstract The stress wave activity produced in a surface (12) by a writing instrument (13) during the generation of a given piece of handwriting is detected by a transducer (16) and is electrically processed. The stress wave activity is compared with a stress wave activity, produced during at least one previous generation of the given piece of handwriting, held in a store (26), by a processing unit (24) in order to determine whether the detected and stored handwriting pieces have a common author. If the detected and stored handwriting pieces are determined to have a common author a weighted average of the stored stress wave activity and the detected stress wave activity is produced. The weighted average includes a weighted average of the amplitudes and a weighted average of times of events. This weighted average stress wave activity then replaces the stored stress wave activity in the store (26). This allows natural variations in the way an individual writes a given piece of handwriting to be accommodated without false indications of inauthenticity.
Inventors
- 👤 John Richard Webster
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 23:39
CPC Classifications
G; G06; G06V; G06V40/00; G06V40/30; G06V40/37; G06F; G06F18/00; G06F18/20; G06F18/28; G07; G07C; G07C9/00; G07C9/30; G07C9/32; G07C9/35
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
237 words
A device (10) for verifying personal handwriting comprising means (16) for detecting a time varying characteristic produced by the motion of a writing instrument (13) on a surface of a body (12) during the generation of a given piece of handwriting, means (24) for comparing said detected time varying characteristic with a stored (26) time varying characteristic produced by the motion of the same or a different writing instrument (13) on the same or a different body (12) during the generation of at least one previous like piece of handwriting to provide an indication of whether the generation of said handwriting pieces produce substantially common time varying characteristics and thus whether the handwriting pieces have been generated by a common author characterised in that the means (24) for comparing said detected time varying characteristic with said stored time varying characteristic is arranged to compare each point or portion of said detected time varying characteristic with said stored time varying characteristic, means (24) is arranged to produce a weighted average of said stored (26) time varying characteristic and said detected time varying characteristic produced during the generation of a piece of handwriting by a common author, means (24) is arranged to replace said stored (26) time varying characteristic with the weighted average of said stored (26) time varying characteristic and said detected time varying characteristic produced during the generation of a piece of handwriting by a common author.
Claim 2
Dependent Claim
69 words
A device as claimed in claim 1 in which the means (24) for comparing the detected time varying characteristic with the stored (26) time varying characteristic is arranged to distort each point or portion of said detected time varying characteristic in time to obtain a best match with the stored (26) time varying characteristic and stores each of the values of time distortion required to obtain the best match.
Claim 3
Dependent Claim
130 words
A device as claimed in claim 2 in which the means (24) for producing a weighted average of the detected time varying characteristic and the stored (26) time varying characteristic is arranged to distort each point or portion of the detected time varying characteristic in time by the corresponding one of the values stored by the comparing means (24) to obtain the best match with the stored (26) time varying characteristics, and is arranged to produce weighted average magnitudes of said time varying characteristic between the stored (26) time varying characteristic and the time distorted detected time varying characteristic and is arranged to produce a weighted average of time of events by displacing the weighted average magnitudes of said time varying characteristic in time towards the detected time varying characteristic.
Claim 4
Dependent Claim
71 words
A device as claimed in claim 2 or claim 3 in which the means (24) for comparing the detected time varying characteristic with the stored (26) time varying characteristic is arranged to detect relatively low or zero magnitudes of the time varying characteristic and is arranged to reduce the errors associated with the stored values of time distortion required to obtain the best match with the stored (26) time varying characteristic.
Claim 5
Independent Claim
43 words
A device as claimed in any of claims 1 to 4 in which the time varying characteristic is capacitance, the means for detecting the time varying characteristic is a capacitor defined between the writing instrument (13) and the surface of the body (12).
Claim 6
Independent Claim
53 words
A device as claimed in any of claims 1 to 4 in which the time varying characteristic is load or pressure, the means for detecting the time varying characteristic is a load cell for detecting load or pressure produced by the motion of the writing instrument (13) on the surface of the body.
Claim 7
Independent Claim
57 words
A device as claimed in any of claims 1 to 4 in which the time varying characteristic is stress wave activity, the means (16) for detecting the time varying characteristic is an acoustic emission transducer for detecting the stress wave activity produced by the motion of the writing instrument (13) on the surface of the body (12).
Claim 8
Dependent Claim
23 words
A device as claimed in claim 7 in which the means for detecting the stress wave activity comprises a resonant acoustic emission transducer.
Claim 9
Dependent Claim
25 words
A device as claimed in claim 7 or claim 8 comprising a means (20) for processing the detected stress wave activity including an enveloping means.
Claim 10
Independent Claim
197 words
A method for verifying personal handwriting comprising detecting a time varying characteristic produced by the motion of a writing instrument on a surface of a body during the generation of a given piece of handwriting, comparing the detected time varying characteristic with a stored time varying characteristic produced by the motion of the same or a different writing instrument on the same or a different surface of the same or a different body during the generation of at least one previous like piece of handwriting to provide an indication of whether the generation of said handwriting pieces produce common time varying characteristics and thus whether the pieces have been generated by a common author, characterised by comparing each point or portion of the detected time varying characteristic with the stored time varying characteristic, producing a weighted average of the stored time varying characteristic and the detected time varying characteristic produced during the generation of a piece of handwriting by a common author, replacing the stored time varying characteristic with the weighted average of the stored time varying characteristic and the detected time varying characteristic produced during the generation of a piece of handwriting by a common author.
Claim 11
Dependent Claim
49 words
A method as claimed in claim 10 in which each part or portion of the detected time varying characteristic is distorted in time to obtain a best match with the stored time varying characteristic, each of the values of time distortion required to obtain the best match is stored.
Claim 12
Dependent Claim
93 words
A method as claimed in claim 11 in which each part or portion of the detected time varying characteristic is distorted in time by the corresponding one of the stored values to obtain the best match with the stored time varying characteristic, producing weighted average magnitudes of said time varying characteristic between the stored time varying characteristic and the time distorted detected time varying characteristic and producing a weighted average of time of events by displacing the weighted average magnitudes of said time varying characteristic in time towards the detected time varying characteristic.
Claim 13
Independent Claim
20 words
A method as claimed in any of claims 10 to 12 in which the time varying characteristic detected is capacitance.
Claim 14
Independent Claim
22 words
A method as claimed in any of claims 10 to 12 in which the time varying characteristic detected is load or pressure.
Claim 15
Independent Claim
22 words
A method as claimed in any of claims 10 to 12 in which the time varying characteristic detected is stress wave activity.
References Cited (Backward Citations)
No citation records indexed.
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