US5141303A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for discriminating eye fundus blood vessels
Assignee: Kowa Co Ltd
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Filing: 1990-05-07
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Granted: 1992-08-25
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Expires: 2010-05-07
Abstract
Abstract Light beams of predetermined different wavelengths are projected into an eye fundus and light scattered therefrom is detected to distinguish blood vessels from surrounding tissue in the eye fundus. The method and apparatus of the invention makes full use of differences in light absorbing/reflecting characteristics in the fundus blood vessels and surrounding tissue and is therefore able to reliably distinguish whether light projected at the eye fundus is scattered by a blood vessel or by surrounding tissue.
Inventors
- 👤 Tetsuya Yamamoto
- 👤 Koji Ogino
- 👤 Toshiaki Sugita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:43
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/12; A61B3/1225; A61B3/1233
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
146 words
A method for discriminating eye fundus blood vessels in which a light beam of predetermined wavelength is projected into the eye fundus and light scattered therefrom is detected to distinguish blood vessels from surrounding tissue in the eye fundus, comprising the steps of: projecting light of predetermined first and second wavelengths onto an eye fundus, the first wavelength light effective to better reflect from the surrounding tissue than the second wavelength light and the second wavelength light effective to better reflect from the blood vessels than the first wavelength light; separately detecting first and second wavelength light scattered from fundus blood vessels and surrounding tissue; obtaining the difference or the ratio, or the common logarithm of the ratio, between the detected light of the first and second wavelengths; and comparing the value thus obtained with a predetermined value to distinguish the blood vessels from surrounding tissue.
Claim 2
Independent Claim
146 words
A method for discriminating eye fundus blood vessels in which a light beam of predetermined wavelength is projected into the eye fundus and light scattered therefrom is detected to distinguish blood vessels from surrounding tissue in the eye fundus, comprising the steps of: projecting light of predetermined first and second wavelengths onto an eye fundus, the first wavelength light effective to better reflect from the surrounding tissue than the second wavelength light and the second wavelength light effective to better reflect from the blood vessels than the first wavelength light; separately detecting first and second wavelength light scattered from fundus blood vessels and surrounding tissue; obtaining the difference or the ratio, or the common logarithm of the ratio, between the detected light of the first and second wavelengths; and comparing the value thus obtained with a predetermined value to distinguish the blood vessels from surrounding tissue.
Claim 3
Dependent Claim
25 words
The method according to claim 1, wherein the scattered light is imaged and detected at an image plane that is conjugate with the eye fundus.
Claim 4
Dependent Claim
14 words
The method according to claim 1, wherein the projected light scans the eye fundus.
Claim 5
Dependent Claim
42 words
The method according to claim 1, wherein the first wavelength light has a predetermined wavelength selected from the range 560 nm to 580 nm and the second wavelength light has a predetermined wavelength selected from the range 600 nm to 660 nm.
Claim 6
Independent Claim
99 words
A method for discriminating eye fundus blood vessels, comprising the steps of: projecting a first wavelength light and a second wavelength light onto an eye fundus; detecting the fist and second wavelength light scattered by the eye fundus blood vessels and surrounding tissue to produce a detected output; calculating from the detected output at least one of a difference, ratio or common logarithm of a ratio between the detected scattered first and second wavelength light to produce a corresponding calculated value; and comparing each corresponding calculated value with a respective predetermined value to discriminate the eye fundus blood vessels.
Claim 7
Independent Claim
99 words
A method for discriminating eye fundus blood vessels, comprising the steps of: projecting a first wavelength light and a second wavelength light onto an eye fundus; detecting the fist and second wavelength light scattered by the eye fundus blood vessels and surrounding tissue to produce a detected output; calculating from the detected output at least one of a difference, ratio or common logarithm of a ratio between the detected scattered first and second wavelength light to produce a corresponding calculated value; and comparing each corresponding calculated value with a respective predetermined value to discriminate the eye fundus blood vessels.
Claim 8
Dependent Claim
20 words
A method for discriminating eye fundus blood vessels according to claim 5; wherein the projected light scans the eye fundus.
Claim 9
Dependent Claim
31 words
A method for discriminating eye fundus blood vessels according to claim 5; wherein the scattered light is imaged and detected at an image plane that is conjugate with the eye fundus.
Claim 10
Dependent Claim
48 words
A method for discriminating eye fundus blood vessels according to claim 5; wherein the first wavelength light has a predetermined wavelength selected from the range 560 nm to 580 nm and the second wavelength light has a predetermined wavelength selected from the range 600 nm to 660 nm.
Claim 11
Dependent Claim
66 words
A method for discriminating eye fundus blood vessels according to claim 5; further comprising the step of correcting the detected output to maintain a detected relationship wherein the first wavelength light is detected as being better reflected from the surrounding tissue than the second wavelength light and the second wavelength light is detected as being better reflected from the blood vessels than the first wavelength light.
Claim 12
Independent Claim
110 words
An apparatus for discriminating eye fundus blood vessels, comprising: projecting means for projecting a first wavelength light and a second wavelength light onto an eye fundus; detecting means for detecting the first and second wavelength light scattered by the eye fundus blood vessels and surrounding tissue to produce a detected output signal; calculating means for calculating from the detected output signal at least one of a difference, ratio or common logarithm of a ratio between the detected scattered first and second wavelength light to produce a corresponding calculated value; and comparing means for comparing each corresponding calculated value with a respective predetermined value to discriminate the eye fundus blood vessels.
Claim 13
Independent Claim
110 words
An apparatus for discriminating eye fundus blood vessels, comprising: projecting means for projecting a first wavelength light and a second wavelength light onto an eye fundus; detecting means for detecting the first and second wavelength light scattered by the eye fundus blood vessels and surrounding tissue to produce a detected output signal; calculating means for calculating from the detected output signal at least one of a difference, ratio or common logarithm of a ratio between the detected scattered first and second wavelength light to produce a corresponding calculated value; and comparing means for comparing each corresponding calculated value with a respective predetermined value to discriminate the eye fundus blood vessels.
Claim 14
Dependent Claim
23 words
An apparatus for discriminating eye fundus blood vessels according to claim 10; wherein the projecting means includes means for scanning the eye fundus.
Claim 15
Dependent Claim
36 words
An apparatus for discriminating eye fundus blood vessels according to claim 10; wherein the detecting means includes means for detecting and imaging the scattered light at an image plane that is conjugate with the eye fundus.
Claim 16
Dependent Claim
48 words
An apparatus for discriminating eye fundus blood vessels according to claim 10; wherein the first wavelength light has a predetermined wavelength selected from the range 560 nm to 580 nm and the second wavelength light has a predetermined wavelength selected from the range 600 nm to 660 nm.
Claim 17
Dependent Claim
67 words
An apparatus for discriminating eye fundus blood vessels according to claim 10; further comprising correcting means for correcting the detected output signal to maintain a detected relationship wherein the first wavelength light is detected as being better reflected from the surrounding tissue than the second wavelength light and the second wavelength light is detected as being better reflected from the blood vessels than the first wavelength light.
References Cited (Backward Citations)
US4157708A
Cited
US4854692A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-08-25 | 1996-02-24 | 1996-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-25 | 2000-02-24 | 2000-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-25 | 2004-02-24 | 2004-08-25 | $7700.00 | Window Closed / Lapsed |