US3723648A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for discriminating against masking reflections
Assignee: SRI International Inc
•
Filing: 1971-02-01
•
Granted: 1973-03-27
•
Expires: 1991-02-01
Abstract
Abstract A method and means for discriminating against masking reflections reflected by an object or medium separating an observer from an object which it is desired to view. The desired object and medium are both illuminated by two alternating light sources emitting light of two different wave lengths. The light sources are adjusted so that a detector detects equal amounts of light reflected by the masking medium due to each light source. Assuming, however, that the object which it is desired to view has different spectral characteristics than the masking medium, it will reflect varying amounts of light from the two light sources as the light sources alternate. The reflected light from both the medium and the desired object is incident on a sensing means such as an image dissector and means are provided to separate the AC signal which will be due to reflections from the desired object from the DC signal which will be due to reflections from the masking medium.
Inventors
- 👤 T Cornsweet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:58
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
141 words
A method for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising the sTeps of illuminating the object and masking medium with alternating light from two light sources having different spectral outputs, adjusting the intensities of the two light sources so that the amount of light from one light source that is reflected by the masking medium is approximately equal to the amount of light from the other light source that is reflected by the masking medium, sensing the total light reflected by the object and masking medium as the two light sources alternate and generating an electrical signal in response thereto, filtering the electrical signal to extract the AC portion thereof and displaying the AC portion whereby a view of only the object is displayed.
Claim 2
Independent Claim
141 words
A method for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising the sTeps of illuminating the object and masking medium with alternating light from two light sources having different spectral outputs, adjusting the intensities of the two light sources so that the amount of light from one light source that is reflected by the masking medium is approximately equal to the amount of light from the other light source that is reflected by the masking medium, sensing the total light reflected by the object and masking medium as the two light sources alternate and generating an electrical signal in response thereto, filtering the electrical signal to extract the AC portion thereof and displaying the AC portion whereby a view of only the object is displayed.
Claim 3
Independent Claim
140 words
A method for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising the steps of illuminating the object and masking medium with light to form a reflected object beam and a reflected masking beam, alternately filtering the reflected object and masking beams with at least two filters having different spectral characteristics with light transmissivity of the at least two filters adjusted so that equal intensities of the reflected masking beam are transmitted therethrough, sensing the filtered reflected object and masking beams as the at least two filters are alternated and generating an electrical signal in response thereto, separating AC components of the electrical signals from DC components thereof and converting the AC portion to a display whereby a view of only the object is obtained.
Claim 4
Independent Claim
140 words
A method for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising the steps of illuminating the object and masking medium with light to form a reflected object beam and a reflected masking beam, alternately filtering the reflected object and masking beams with at least two filters having different spectral characteristics with light transmissivity of the at least two filters adjusted so that equal intensities of the reflected masking beam are transmitted therethrough, sensing the filtered reflected object and masking beams as the at least two filters are alternated and generating an electrical signal in response thereto, separating AC components of the electrical signals from DC components thereof and converting the AC portion to a display whereby a view of only the object is obtained.
Claim 5
Dependent Claim
174 words
Apparatus for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising alternately excited first and second light sources for illuminating the object and masking medium whereby object and masking reflected light beams are formed, said first and second light sources being adjusted so that the masking reflected light beams due to each source are of the same intensity, sensing means responsive to said reflected object and masking light beams for developing an electrical signal, and display means responsive to said electrical signal for generating a display which is a view of the object uncontaminated by masking reflections, said sensing means comprising a television camera having a frame rate approximately equal to the rate of alternation of said first and second light sources and including means for subtracting succeeding frames to form a difference signal whereby said display means is responsive to said difference signal for generating a display which is a view of the object uncontaminated by masking reflections.
Claim 6
Dependent Claim
174 words
Apparatus for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising alternately excited first and second light sources for illuminating the object and masking medium whereby object and masking reflected light beams are formed, said first and second light sources being adjusted so that the masking reflected light beams due to each source are of the same intensity, sensing means responsive to said reflected object and masking light beams for developing an electrical signal, and display means responsive to said electrical signal for generating a display which is a view of the object uncontaminated by masking reflections, said sensing means comprising a television camera having a frame rate approximately equal to the rate of alternation of said first and second light sources and including means for subtracting succeeding frames to form a difference signal whereby said display means is responsive to said difference signal for generating a display which is a view of the object uncontaminated by masking reflections.
Claim 7
Dependent Claim
185 words
Apparatus for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising light source means forming a light beam for illuminating the object and masking medium whereby object and masking medium reflected light beams are formed, an optical filter having at least two portions having different spectral characteristics, means for positioning said optical filter so that in an alternate fashion each of the two portions thereof filters both said object and masking medium reflected light beams to form filtered object and masking medium reflected light beams, a detector on which said filtered object and masking medium reflected light beams are incident, said detector adapted to generate an electrical signal, having an AC and a DC component in response thereto, the light transmissivity of said two portions being adjusted so that as the two portions alternate equal intensities of masking medium filtered reflected light beams are transmitted therethrough as sensed by said detector, and display means responsive to said AC component for generating a display of the object uncontaminated by masking reflections.
Claim 8
Dependent Claim
185 words
Apparatus for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising light source means forming a light beam for illuminating the object and masking medium whereby object and masking medium reflected light beams are formed, an optical filter having at least two portions having different spectral characteristics, means for positioning said optical filter so that in an alternate fashion each of the two portions thereof filters both said object and masking medium reflected light beams to form filtered object and masking medium reflected light beams, a detector on which said filtered object and masking medium reflected light beams are incident, said detector adapted to generate an electrical signal, having an AC and a DC component in response thereto, the light transmissivity of said two portions being adjusted so that as the two portions alternate equal intensities of masking medium filtered reflected light beams are transmitted therethrough as sensed by said detector, and display means responsive to said AC component for generating a display of the object uncontaminated by masking reflections.
Claim 9
Dependent Claim
30 words
Apparatus in accordance with claim 4 including filtering mEans for separating said electrical signal into AC and DC components and wherein said display means is responsive to said AC component.
Claim 10
Dependent Claim
249 words
Apparatus for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising light source means forming a light beam for illuminating the object and masking medium whereby object and masking medium reflected light beams are formed, an optical filter having at least two portions having different spectral characteristics, means for positioning said optical filter so that in an alternate fashion each of the two portions thereof filters both said object and masking medium reflected light beams to form filtered object and masking medium reflected light beams, a detector on which said filtered object and masking medium reflected light beams are incident, said detector adapted to generate an electrical signal having an AC and a DC component in response thereto, the light transmissivity of said two portions being adjusted so that as the two portions alternate equal intensities of masking medium filtered reflected light beams are transmitted therethrough as sensed by said detector, and display means responsive to said AC component for generating a display of the object uncontaminated by masking reflections, said detector comprising a television camera having a frame rate approximately equal to the rate of alternation of said first and second portions of said optical filter and including means for subtracting succeeding frames to form a difference signal whereby said display means is responsive to said difference signal for generating a display which is a view of the object uncontaminated by masking reflections.
Claim 11
Dependent Claim
249 words
Apparatus for viewing an object separated from a viewer by a masking medium wherein the object and the masking medium have different spectral reflection characteristics comprising light source means forming a light beam for illuminating the object and masking medium whereby object and masking medium reflected light beams are formed, an optical filter having at least two portions having different spectral characteristics, means for positioning said optical filter so that in an alternate fashion each of the two portions thereof filters both said object and masking medium reflected light beams to form filtered object and masking medium reflected light beams, a detector on which said filtered object and masking medium reflected light beams are incident, said detector adapted to generate an electrical signal having an AC and a DC component in response thereto, the light transmissivity of said two portions being adjusted so that as the two portions alternate equal intensities of masking medium filtered reflected light beams are transmitted therethrough as sensed by said detector, and display means responsive to said AC component for generating a display of the object uncontaminated by masking reflections, said detector comprising a television camera having a frame rate approximately equal to the rate of alternation of said first and second portions of said optical filter and including means for subtracting succeeding frames to form a difference signal whereby said display means is responsive to said difference signal for generating a display which is a view of the object uncontaminated by masking reflections.
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) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |