Apparatus and method for non-invasive measurement of stretch
OwnerNejat Guzelsu, Thomas W. Findley +3inventors
InventorsNejat Guzelsu, Thomas W. Findley, John Federici, Hans R. Chaudhry, Arthur B. Ritter
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Abstract
A method and apparatus for noninvasive, non-contacting measurement of stretches and deformations on the surface of a material or an object by utilizing changes which occur in the reflection characteristics of the material due to an applied stretch load is presented. The present invention may assume various embodiments for different applications, such as soft tissue stretch determination, plastic material deformation measurements and sensors which can be integrated into various measurement devices.
Claims66
A method for determining the amount of stretch at a diffuse reflectance surface of an object under an applied load, the method comprising:
- exposing the diffuse reflectance surface of the object to an incident light beam;
- and
- measuring changes in the reflection characteristics of the diffuse reflectance surface due to the applied load.
A method for quantitatively assessing the amount of stretch induced by an applied load on an object which has a diffuse reflectance surface, the method comprising the following sequence of steps:
- producing a light beam;
- polarizing the light beam into a desired first of two perpendicular orientations which include a first orientation wherein the incident light is polarized perpendicular to the plane of incidence (s polarization) and a second orientation wherein the incident light is polarized parallel to the plane of incidence (p polarization);
- exposing the diffuse reflectance surface of the object to the incident chopped, polarized light beam;
- polarizing at least a portion of the light reflected from the diffuse reflectance surface into the desired first of said two perpendicular orientations;
- and
- detecting the intensity of the polarized, reflected light of the first orientation;
- wherein the amount of stretch induced by the applied load on the object is correlated to the intensity of polarized, reflected light.
A method for noninvasively, quantitatively determining the amount of stretch in soft tissue under an applied load, the method comprising:
- producing a focused light beam;
- polarizing the light beam into a desired one of two perpendicular orientations which include a first orientation wherein the incident light is polarized perpendicular to the plane of incidence (s polarization) and a second orientation wherein the incident light is polarized parallel to the plane of incidence (p polarization);
- exposing the tissue to the incident chopped, polarized light beam;
- polarizing at least a portion of the light reflected from the tissue into the desired one of said two perpendicular orientations;
- aperturing at least a portion of the reflected light in order to define a solid angle of collected light;
- focusing at least a portion of the reflected light;
- and
- detecting the intensity of the polarized, reflected light;
- wherein the amount of stretch induced by the applied load on the tissue is correlated to the intensity of polarized, reflected light.
An apparatus for use in noninvasively determining the mechanical deformation at a diffuse reflectance surface of a material, the apparatus comprising:
- a light source for generating a light beam;
- means for polarizing the light beam into a desired one of two perpendicular orientations;
- a lens for focusing the light beam onto the diffuse reflectance surface of the material;
- a light analyzer means for selectively collecting light reflected from the diffuse reflectance surface and polarizing the collected light into one of said two perpendicular orientations;
- and
- light intensity measurement means for measuring the intensity of the collected, polarized light emitted from said polarization analyzer means;
- whereby changes in light intensity provide an indication of the amount of stretch in the material.
A method for quantitatively assessing the amount of stress by measuring stretch induced by an applied load on an object which has a diffuse reflectance surface, the method comprising the following sequence of steps:
- producing a light beam;
- polarizing the light beam into a desired first of two perpendicular orientations which include a first orientation wherein the incident light is polarized perpendicular to the plane of incidence (s polarization) and a second orientation wherein the incident light is polarized parallel to the plane of incidence (p polarization);
- exposing the diffuse reflectance surface of the object to the incident chopped, polarized light beam;
- polarizing at least a portion of the light reflected from the diffuse reflectance surface into the desired first of said two perpendicular orientations;
- and
- detecting the intensity of the polarized, reflected light of the first orientation;
- wherein the amount of stretch induced by the applied load on the object is correlated to the intensity of polarized, reflected light and
- determining the amount of stress by measuring stretch.
Dependencies are inferred from the claim text.