Patent EA-001936-B1 (EA)
Title: Method and apparatus for reflected imaging analysis
Inventor: GRONER WARREN
IPC: G06F19/00
Filed: 1996-10-21
Abstract: 1. A method for measuring characteristics of an absorbing object located within and below the surface of a body, comprising: directing light polarized in a first plane onto the surface of the body; passing light reflected from a subsurface region of the body located behind the object to be measured through an analyzer having a second plane of polarization substantially orthogonal to the first plane of polarization; detecting the reflected light after it has passed through the analyzer; and measuring characteristics of the object as a function of the relationship between the intensity of reflected light that is absorbed by the object to and the intensity of reflected light that is not absorbed by the object. 2. The method according to claim 1, wherein measuring characteristics of an object is carried out by detecting the reflected light with the first wavelength absorbed by the object and reflected light with the second wavelength that is not absorbed by the object and determining the negative logarithm of the quotient obtained by dividing the intensity of the reflection with the first wavelength by the intensity of reflection with the second wavelength. 3. The method according to claim 2, wherein the reflection with the first and second wavelength is obtained by passing the reflected light through the first and second filters of wavelengths respectively. 4. The method according to claims 1 to 3, wherein the detected reflected light is in the form of an image of the object to be measured. 5. The method according to claim 4, wherein the image to be analyzed is segmented from an image of the object to be measured. 6. The method according to claims 1 to 5, wherein the body comprises subject's capillary vascular system, and an object to be measured is blood being in a vessel of said system. 7. The method according to claim 6, wherein separating a moving portion of the raw reflected image from a stationary portion of the raw reflected image is obtained of the same vessel portion in the first and second span of time and extract the first image from the second image. 8. The method according to claim 6, wherein the first wavelength is 550 nm and the second wavelength is 650 nm. 9. The method according to claim 6, wherein the image to be analyzed is carried out using a spatial frequency criterion of blood cells. 10. The method according to claim 6, wherein a characteristic to be measured is a volume hemoglobin concentration in blood determined by a mean reflected light intensity. 11. The method according to claim 6, wherein characteristics to be measured are hematocrit number determined by a volume of cells per unit volume of blood, a volume hemoglobin concentration in blood determined by a mean reflected light intensity. 12. The method according to claim 6, wherein characteristic to be measured is a volume bilirubin concentration in blood determined by a mean reflected light intensity. 13. The method according to claim 12 wherein the first wavelength is 450 nm and the second wavelength is 600 nm. 14. Apparatus for carrying out the method of claim 1, comprising a light source (1502) for illuminating an absorbing object located below the surface of a body, a polarizer (1510) for polarizing radiation of the light source, a detecting means (1560) for detecting the radiation reflected from a subsurface region of the body, an analyzer (1520) disposed in the path of said reflected radiation between the object and the detecting means with its plane of polarization being orthogonal to the plane of polarization of the said polarizer, and a means for measuring optical characteristics of the reflected radiation detected by the detecting means as a function of the relationship between the intensity of the reflected radiation not absorbed by said object and the intensity of the reflected radiation after absorption by said object, said measuring means being coupled to an output of said detecting means. 15. Apparatus according to claim 14, further comprising a beam splitter (1540) for forming a light path between said light source and the illuminated object and a reflected light path fox a reflected image reflected from the illuminated object at a depth less than a multiple scattering length. 16. Apparatus according to claims 14 and 15, wherein said detecting means comprises a camera for capturing the reflected image. 17. Apparatus according to claims 14 to 16, wherein an illuminating object is blood, and said detecting means comprises an image capturing means for capturing a reflected image reflected from the illuminated blood at a depth less than a multiple scattering length, the reflected image traveling along a reflected light path between the illuminated blood and said image capturing means. 18. Apparatus according to claim 17, wherein comprises a dichroic mirror (1540), disposed in the reflected light path between said analyzer and said detecting means for separating the reflected image, passing the first portion of the reflected image to said detecting means, and an additional image capturing means (1570) for capturing the second portion of the reflected image. 19. The apparatus of claim 18, further comprising a first spectral selection means (1552) disposed in the reflected light path between said dichroic mirror and said second image capturing means, and second spectral selection means (1554) disposed in the reflected light path between said dichroic mirror and said additional image capturing means. 20. The apparatus according to claims 19, wherein said first spectral selection means is centered at a wavelength of 550 nm and said second spectral selection means is centered at a wavelength of 650 nm. 21. The apparatus according to claims 14-17, further comprising an objective lens disposed between said polarizer and the object, wherein said detecting means is in a magnified image plane of said objective lens. 22. The apparatus according to claims 14-17, further comprising reflected light separating means (1540) disposed in the reflected light path between said analyzer and said detecting means for separating the reflected light reflected from the illuminated object, wherein a first portion of the reflected light is transmitted through said reflected light separating means to said detecting means, and a second portion of the reflected light is reflected by said reflected light separating means and a second detecting means for detecting the second portion of the reflected light. 23. The apparatus according to claims 14-17, wherein said detecting means further comprises a photodetector. 24. The apparatus according to claims 14-17, wherein further comprising a dichroic separator (1540) disposed in the reflected light path between said analyzer and said detecting means. 25. The apparatus according to claims 14-17, wherein further comprising image separating means (1540) disposed in the reflected light path between said analyzer and said image capturing means for separating the reflected image into a first portion and a second portion. 26. The apparatus according to claim 25, wherein said image separating means comprises a dichroic mirror, wherein the first portion of the reflected image is transmitted through said dichroic mirror to said image capturing means, and the second portion of the reflected image is reflected by said dichroic mirror. 27. The apparatus according to claim 25 or 26, wherein comprises a second image capturing means (1570) for capturing said second portion of the reflected image. 28. The apparatus according to claim 25, wherein comprises a second spectral selection means (1554) disposed in the reflected light path between said dichroic mirror and said second image capturing means. 29. The apparatus according to claims 14-17, wherein said means for measuring characteristics of the reflected image is an image correcting and analyzing means (1580) coupled to said image capturing means for correcting and analyzing the reflected image.