US4764017A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for identifying timber surface properties
Assignee: Altim Control Oy
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Filing: 1987-01-20
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Granted: 1988-08-16
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Expires: 2007-01-20
Abstract
Abstract A method for identifying timber surface properties using linearly polarized electromagnetic radiation containing various different wavelength components. Of the scattered radiation are measured by wavelength ranges the intensity components I min and I max that are mutually perpendicular as regards their polarization plane, wherein the polarization plane of the component I max is the same as that of the radiation directed to the surface. The identification of the surface types is made on the basis of the information about the color tone of the surface and the fiber structure achieved from the variables I min and P=(I max -I min )/(I max +I min ).
Inventors
- 👤 Kullervo Hirvonen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:05
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89; G01N21/892; G01N21/898; G01N21/8986; G01N21/17; G01N21/21
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
160 words
A method for determining timber surface characteristics comprising the steps of: directing electromagnetic radiation of at least two different wavelengths to the surface to be examined such that each wavelength component is linearly polarized with the polarization plane parallel or perpendicular to the normal growth direction of the wood fibers of the surface to be examined; measuring separately for each wavelength component the intensity components I min and I max of the scattered radiation, the intensity components I min and I max having polarization planes of scattered radiation perpendicular to one another with the polarization plane of the component I max being the same as the polarization plane of the incident radiation; determining the degree of depolarization for one of said wavelength components by using P=(I max -I min )/(I max +I min ); and determining timber surface characteristics using information about the color tones of the variables I min and the degree of depolarization P for one wavelength component.
Claim 2
Independent Claim
160 words
A method for determining timber surface characteristics comprising the steps of: directing electromagnetic radiation of at least two different wavelengths to the surface to be examined such that each wavelength component is linearly polarized with the polarization plane parallel or perpendicular to the normal growth direction of the wood fibers of the surface to be examined; measuring separately for each wavelength component the intensity components I min and I max of the scattered radiation, the intensity components I min and I max having polarization planes of scattered radiation perpendicular to one another with the polarization plane of the component I max being the same as the polarization plane of the incident radiation; determining the degree of depolarization for one of said wavelength components by using P=(I max -I min )/(I max +I min ); and determining timber surface characteristics using information about the color tones of the variables I min and the degree of depolarization P for one wavelength component.
Claim 3
Dependent Claim
36 words
A method according to claim 1 wherein the step of directing electromagnetic radiation includes the step of scanning the timber surface with the red wavelength of a HeNe laser and one wavelength of a blue-green laser.
Claim 4
Dependent Claim
14 words
A method according to claim 2 wherein the blue-green laser is a HeNe laser.
Claim 5
Dependent Claim
14 words
A method according to claim 2 wherein the blue-green laser is an argon laser.
Claim 6
Dependent Claim
29 words
A method according to claim 1 wherein the step of determining the timber surface characteristics includes using the color tones to distinguish rot and bluestain in the timber surface.
Claim 7
Dependent Claim
29 words
A method according to claim 1 wherein the step of determining timber surface characteristics includes using information about the degree of depolarization P for more than one wavelength component.
Claim 8
Dependent Claim
164 words
Apparatus for determining timber surface characteristics comprising: means for directing electromagnetic radiation of at least two different wavelengths to the surface to be examined such that each wavelength component is linearly polarized with the polarization plane parallel or perpendicular to the normal growth direction of the wood fibers of the surface to be examined; means for measuring separately for each wavelength component the intensity component I min and I max of the scattered radiation, the intensity components I min and I max having polarization planes of scattered radiation perpendicular to one another with the polarization plane of the component I max being the same as the polarization plane of the incident radiation; means for determining the degree of polarization for one of said wavelength components by using P=(I max -I min )/(I max +I min ); and means for determining timber surface characteristics using information about the color tones of the components I min and the degree of polarization P for one wavelength component.
Claim 9
Dependent Claim
164 words
Apparatus for determining timber surface characteristics comprising: means for directing electromagnetic radiation of at least two different wavelengths to the surface to be examined such that each wavelength component is linearly polarized with the polarization plane parallel or perpendicular to the normal growth direction of the wood fibers of the surface to be examined; means for measuring separately for each wavelength component the intensity component I min and I max of the scattered radiation, the intensity components I min and I max having polarization planes of scattered radiation perpendicular to one another with the polarization plane of the component I max being the same as the polarization plane of the incident radiation; means for determining the degree of polarization for one of said wavelength components by using P=(I max -I min )/(I max +I min ); and means for determining timber surface characteristics using information about the color tones of the components I min and the degree of polarization P for one wavelength component.
Claim 10
Dependent Claim
27 words
Apparatus according to claim 7 including means for scanning the timber surface with the red wavelength of a HeNe laser and one wavelength of a blue-green laser.
Claim 11
Dependent Claim
13 words
Apparatus according to claim 8 wherein the blue-green laser is a HeNe laser.
Claim 12
Dependent Claim
13 words
Apparatus according to claim 8 wherein the blue-green laser is an argon laser.
Claim 13
Dependent Claim
22 words
Apparatus according to claim 7 including means for using information about the degree of depolarization P for more than one wavelength component.
Claim 14
Dependent Claim
27 words
Apparatus according to claim 7 including means for scanning the timber surface with the red wavelength of a HeNe laser and one wavelength of a blue-green laser.
Claim 15
Dependent Claim
13 words
Apparatus according to claim 12 wherein the blue-green laser is a HeNe laser.
Claim 16
Dependent Claim
13 words
Apparatus according to claim 12 wherein the blue-green laser is an argon laser.
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) | 1991-08-16 | 1992-02-15 | 1992-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-16 | 2000-02-15 | 2000-08-16 | $7700.00 | Window Closed / Lapsed |