US5847394A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Imaging of objects based upon the polarization or depolarization of light
Assignee: Research Foundation of City University of New York
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Filing: 1996-08-28
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Granted: 1998-12-08
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Expires: 2016-08-28
Abstract
Abstract A method and apparatus for imaging objects based upon the polarization or depolarization of light. According to one embodiment, there is provided a method for imaging the surface of a turbid medium, the method comprising the steps of: (a) illuminating the surface of the turbid medium with light, whereby light is backscattered from the illuminated surface of the turbid medium; (b) detecting a pair of complementary polarization components of the backscattered light; and (c) forming an image of the illuminated surface using the pair of complementary polarization components. Preferably, the illuminating light is polarized (e.g., linearly polarized, circularly polarized, elliptically polarized). Where, for example, the illuminating light is linearly polarized, the pair of complementary polarization components are preferably the parallel and perpendicular components to the polarized illuminating light, and the image may be formed by subtracting the perpendicular component from the parallel component, by taking a ratio of the parallel and perpendicular components or by using some combination of a ratio and difference of the parallel and perpendicular components.
Inventors
- 👤 Robert R. Alfano
- 👤 Stavros G. Demos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:35
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/0059; A61B5/0082; A61B5/0091; A61B1/00; A61B1/04; A61B1/042; A61B5/0084; A61B5/0086; A61B5/43; A61B5/4306; A61B5/4312; G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/4795; G01N21/49
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
164 words
A method for imaging a turbid medium at a depth below the surface thereof, said method comprising the steps of: (a) illuminating the turbid medium with a first light of a first wavelength, the first light being polarized and having a first state of polarization, whereby said first light, after entering the turbid medium, emerges therefrom partially depolarized; (b) detecting a component of the partially depolarized first light that is normal to said first state of polarization; (c) illuminating the turbid medium with a second light of a second wavelength, said second wavelength being different from said first wavelength, the second light being polarized and having a second state of polarization, whereby said second light, after entering the turbid medium, emerges therefrom partially depolarized; (d) detecting a component of the partially depolarized second light that is normal to said second state of polarization; and (e) forming an image of the turbid medium using the normal components of the partially depolarized first and second lights.
Claim 2
Independent Claim
164 words
A method for imaging a turbid medium at a depth below the surface thereof, said method comprising the steps of: (a) illuminating the turbid medium with a first light of a first wavelength, the first light being polarized and having a first state of polarization, whereby said first light, after entering the turbid medium, emerges therefrom partially depolarized; (b) detecting a component of the partially depolarized first light that is normal to said first state of polarization; (c) illuminating the turbid medium with a second light of a second wavelength, said second wavelength being different from said first wavelength, the second light being polarized and having a second state of polarization, whereby said second light, after entering the turbid medium, emerges therefrom partially depolarized; (d) detecting a component of the partially depolarized second light that is normal to said second state of polarization; and (e) forming an image of the turbid medium using the normal components of the partially depolarized first and second lights.
Claim 3
Dependent Claim
15 words
The method as claimed in claim 1 wherein the turbid medium is a tissue sample.
Claim 4
Dependent Claim
21 words
The method as claimed in claim 1 wherein the illuminating light comes from a pulsed or continuous light source (lamp, laser).
Claim 5
Dependent Claim
33 words
The method as claimed in claim 1 wherein said image forming step is performed point-by-point or over an area using a photomultiplier or a photodiode or a CCD camera or an equivalent photodetector.
Claim 6
Dependent Claim
54 words
The method as claimed in claim 1 wherein the first and second lights are pulsed or continuous, laser source or any other light source operating in the spectral region between 400 and 1600 nm such as semiconductor laser, Ti:Sapphire laser (800-1000 nm), Cr 4+ :Forsterite laser (1100-1350 nm) or Cr 4+ :YAG (1300-1600 nm).
Claim 7
Dependent Claim
24 words
The method as claimed in claim 1 wherein the different wavelengths used are composed of spectral bands with different central wavelength of the band.
Claim 8
Dependent Claim
34 words
The method as claimed in claim 1 wherein the first and second wavelengths are appropriately chosen to enable the first and second lights, respectively, to reach different mean photon-visit depths in the turbid medium.
Claim 9
Dependent Claim
42 words
The method as claimed in claim 1 wherein each of said first and said second lights is linearly polarized and wherein said detecting steps comprise detecting the perpendicular components of the partially depolarized backscattered light from said first and second lights, respectively.
Claim 10
Dependent Claim
39 words
The method as claimed in claim 1 wherein said forming step comprises calculating a difference between the normal components of the partially depolarized first and second lights and using said difference to form an image of the turbid medium.
Claim 11
Dependent Claim
30 words
The method as claimed in claim 1 wherein said first light has a wavelength of about 570 nm and wherein said second light has a wavelength of about 600 nm.
Claim 12
Dependent Claim
29 words
The method as claimed in claim 1 wherein the delivery of the illuminating light and the light collection for image formation is performed using an endoscope or similar system.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-12-07 | 2002-06-08 | 2002-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-07 | 2006-06-08 | 2006-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-07 | 2010-06-08 | 2010-12-08 | $7700.00 | Window Closed / Lapsed |