US3771129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical processor fingerprint identification apparatus
Assignee: Unisys Corp
•
Filing: 1972-07-27
•
Granted: 1973-11-06
•
Expires: 1992-07-27
Abstract
Abstract An incoherent optical processor fingerprint identification apparatus employing a rotatable grating for inspecting the line orientation in a plurality of preselected finite sample areas of a fingerprint. A detector array including a plurality of detectors each relating to a discrete sample area is disposed to receive an image of the fingerprint filtered through the grating. An incoherent light source and a lens and retroreflective prism assembly function in cooperation with the grating to produce an image thereof superposed on the grating such that minimum light is propagated to the detector array in the absence of an input fingerprint at the prism whereas in the presence of a fingerprint light is diffracted thereby to filter through the grating to the detectors. Maximum light occurs at each detector under a condition of spatial alignment of the grating lines with the ridge lines of the related sample area whereby the time interval between a reference orientation of the grating and the instant of maximum light at each detector may be converted to equivalent electrical signals uniquely representative of a particular fingerprint.
Inventors
- 👤 Mahon D Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:59
CPC Classifications
G; G06; G06V; G06V40/00; G06V40/10; G06V40/12; G06V40/1365; G06V10/00; G06V10/88
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
356 words
Pattern inspection apparatus comprising a rotatable grating having alternate light transmissive and reflective lines, means including a light source for directing a light beam onto the grating, means disposed in the path of light propagated from a part of said grating irradiated by the light beam of the light source for directing light received from the grating back onto the grating to produce in superposed relation with said grating part an equivalent size image thereof wherein the image light impinges on alternate lines of the grating, said grating image producing means including means for supporting an input pattern to be inspected in the light received from the grating, said input pattern being characterized by light transmissive or reflective lines of random orientation over the area of the pattern having the effect when present at said supporting means of diffracting light which is spatially separated from the grating image light at the location of the grating, means for rotating the grating to move the grating lines illuminated by the grating image in a common plane transversely of the light beam directed thereon from the light source whereby the superposed grating image light continuously impinges on alternate lines of the grating, means disposed to receive, under the condition of an input pattern present at said supporting means, light diffracted by the pattern and filtered by the grating to the exclusion of substantially all of the grating image light for producing an image of the pattern, a detector array disposed for receiving the light of the pattern image, said detector array including a plurality of detectors each arranged to receive light forming an image of a discrete sample area of the input pattern, the image light of each said descrete sample area being diffracted in a prescribed direction in accordance with the line orientation in the respective sample areas whereby the diffracted light reaching each detector passes through an extremum value during each half revolution of the grating, and means for determining the angular orientation of the grating relative to a reference orientation at the instant of an extremum value of the light intensity at the respective light detectors.
Claim 2
Dependent Claim
356 words
Pattern inspection apparatus comprising a rotatable grating having alternate light transmissive and reflective lines, means including a light source for directing a light beam onto the grating, means disposed in the path of light propagated from a part of said grating irradiated by the light beam of the light source for directing light received from the grating back onto the grating to produce in superposed relation with said grating part an equivalent size image thereof wherein the image light impinges on alternate lines of the grating, said grating image producing means including means for supporting an input pattern to be inspected in the light received from the grating, said input pattern being characterized by light transmissive or reflective lines of random orientation over the area of the pattern having the effect when present at said supporting means of diffracting light which is spatially separated from the grating image light at the location of the grating, means for rotating the grating to move the grating lines illuminated by the grating image in a common plane transversely of the light beam directed thereon from the light source whereby the superposed grating image light continuously impinges on alternate lines of the grating, means disposed to receive, under the condition of an input pattern present at said supporting means, light diffracted by the pattern and filtered by the grating to the exclusion of substantially all of the grating image light for producing an image of the pattern, a detector array disposed for receiving the light of the pattern image, said detector array including a plurality of detectors each arranged to receive light forming an image of a discrete sample area of the input pattern, the image light of each said descrete sample area being diffracted in a prescribed direction in accordance with the line orientation in the respective sample areas whereby the diffracted light reaching each detector passes through an extremum value during each half revolution of the grating, and means for determining the angular orientation of the grating relative to a reference orientation at the instant of an extremum value of the light intensity at the respective light detectors.
Claim 3
Dependent Claim
31 words
The apparatus of claim 1 wherein the angle determining means includes means for generating a signal representative of each angle, and further comprising means for storing the respective angle representative signals.
Claim 4
Dependent Claim
44 words
The apparatus of claim 1 wherein the grating lines are of substantially uniform width, and the grating rotational axis passes through the boundary of adjoining grating lines and is coincident with the axis of the light beam directed onto the grating from the source.
Claim 5
Dependent Claim
189 words
The apparatus of claim 1 wherein the rotational axis of the grating is skewed relative to the axis of the light beam directed thereon from the light source which is positioned on one side of the grating, and the detector array and the gratinG image producing means are disposed in angularly spaced relation to the light source on the side of the grating opposite from the light source, said grating image producing means being so constructed and arranged relative to the grating that the light beam from the light source incident on the grating is transmitted through the transmissive grating lines to impinge on said grating image producing means and be directed therefrom to propagate back onto the transmissive grating lines whereby in the absence of an input pattern substantially none of the light directed back to the grating reaches the detector array whereas in the presence of an input pattern at said supporting means some of the light impinging on said grating image producing means is diffracted by the input pattern so as to propagate onto the reflective grating lines to be reflected therefrom to the detector array.
Claim 6
Dependent Claim
88 words
The apparatus of claim 4 wherein the grating image producing means includes a lens and retroreflective prism, the lens being positioned intermediate the prism and grating at a distance from the grating equal to the focal length of the lens, and the prism being oriented so that light enters the prism from the lens and leaves the prism to return to the lens through a first surface adjacent the lens, a second surface of the prism constituting the supporting means for supporting the input pattern to be inspected.
Claim 7
Dependent Claim
210 words
The apparatus of claim 5 wherein the size of the first surface of the prism relative to the light impinging thereon is such that a first part of the impinging light passes through the first prism surface to strike the second surface, which is adapted for supporting the input pattern, and be deflected therefrom to a third surface of the prism from which the light is reflected back through the first surface and adjacent lens to the grating while a second part of the impinging light passes through the first prism surface to strike the third surface and be deflected therefrom to the second surface from which the light is reflected back through the first surface and adjacent lens to the grating, the prism being oriented relative to the lens so that the pathlength of the first part of the beam from the pattern supporting surface to the lens is different than the pathlength of the second part of the beam from the pattern supporting surface to the lens thereby providing two spatially separated images of an input pattern present at the second prism surface, one of said pattern images being formed at the detector array and the other image being formed at a location apart from the detector array.
Claim 8
Dependent Claim
180 words
The apparatus of claim 1 wherein the rotational axis of the grating is skewed relative to the axis of the light beam directed thereon from the light source, the detector array is positioned on one side of the grating, and the light source and the grating image porducing means are disposed in spaced relation on the side of the grating opposite from the detector array, said grating image producing means being so constructed and arranged relative to the grating that the light beam from the light source incident on the grating is reflected from the reflective grating lines to impinge on said grating image producing means and be directed therefrom to propagate back onto the reflective grating lines whereby in the absence of an input pattern substantially none of the light directed back to the grating reaches the detector array whereas in the presence of an input pattern at said supporting means some of the light impinging on said grating image producing means is diffracted by the input pattern to propagate through the transmissive grating lines to the detector array.
Claim 9
Dependent Claim
88 words
The apparatus of claim 7 wherein the grating image producing means includes a lens and retroreflective prism, the lens being positioned intermediate the prism and grating at a distance from the grating equal to the focal length of the lens, and the prism being oriented so that light enters the prism from the lens and leaves the prism to retuRn to the lens through a first surface adjacent the lens, a second surface of the prism constituting the supporting means for supporting the input pattern to be inspected.
Claim 10
Dependent Claim
210 words
The apparatus of claim 8 wherein the size of the first surface of the prism relative to the light impinging thereon is such that a first part of the impinging light passes through the first prism surface to strike the second surface, which is adapted for supporting the input pattern, and be deflected therefrom to a third surface of the prism from which the light is reflected back through the first surface and adjacent lens to the grating while a second part of the impinging light passes through the first prism surface to strike the third surface and be deflected therefrom to the second surface from which the light is reflected back through the first surface and adjacent lens to the grating, the prism being oriented relative to the lens so that the pathlength of the first part of the beam from the pattern supporting surface to the lens is different than the pathlength of the second part of the beam from the pattern supporting surface to the lens thereby providing two spatially separated images of an input pattern present at the second prism surface, one of said pattern images being formed at the detector array and the other image being formed at a location apart from the detector array.
Claim 11
Dependent Claim
62 words
The apparatus of claim 4 wherein the grating image producing means includes a light reflective member and a lens positioned intermediate the grating and light reflective member at a distance from the grating equal to the focal length of the lens and further including means for supporting a transparency of the input pattern intermediate the lens and reflective member adjacent the latter.
Claim 12
Dependent Claim
62 words
The apparatus of claim 7 wherein the grating image producing means includes a light reflective member and a lens positioned intermediate the grating and light reflective member at a distance from the grating equal to the focal length of the lens and further including means for supporting a transparency of the input pattern intermediate the lens and reflective member adjacent the latter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |