Estimating material properties using speckle statistics
AssigneeCanon Kabushiki Kaisha
InventorSiu-Kei Tin
Life of this patent
Estimating the term…
Abstract
A surface roughness value and a sub-surface scattering property of a material are estimated. The material is illuminated with a light beam with controlled coherence properties at multiple incident angles. Multiple speckle patterns are recorded, each speckle pattern being recorded for a respective one of the multiple incident angles. Both of a surface roughness value and a sub-surface scattering property of the material are estimated by calculations using the multiple speckle patterns and the incident angle for each such speckle pattern.
Claims17
A method of estimating both of a surface roughness value and a sub-surface scattering property of a material, the method comprising:
- illuminating the material with a light beam with controlled coherence properties at multiple incident angles;
- recording multiple speckle patterns, each speckle pattern being recorded for a respective one of the multiple incident angles;
- and
- estimating both of a surface roughness value and a sub-surface scattering property of the material by calculations using the multiple speckle patterns and the incident angle for each such speckle pattern,
- wherein the estimating step comprises:
- calculating, for each of the multiple speckle patterns, a numeric value for a parameter;
- fitting the numeric values to a model, wherein the model defines relatedness amongst all of the parameter, surface roughness, the sub-surface scattering property, and the incident angle;
- and
- estimating both of the surface roughness value and the sub-surface scattering property of the material from the fitted model.
An apparatus for estimating both of a surface roughness value and a sub-surface scattering property of a material, comprising:
- a computer-readable memory constructed to store computer-executable process steps;
- and
- a processor constructed to execute the computer-executable process steps stored in the memory;
- wherein the process steps stored in the memory cause the processor to:
- illuminate the material with a light beam with controlled coherence properties at multiple incident angles;
- record multiple speckle patterns, each speckle pattern being recorded for a respective one of the multiple incident angles;
- and
- estimate both of a surface roughness value and a sub-surface scattering property of the material by calculations using the multiple speckle patterns and the incident angle for each such speckle pattern,
- wherein the estimating comprises:
- calculating, for each of the multiple speckle patterns, a numeric value for a parameter;
- fitting the numeric values to a model, wherein the model defines relatedness amongst all of the parameter, surface roughness, the sub-surface scattering property, and the incident angle;
- and
- estimating both of the surface roughness value and the sub-surface scattering property of the material from the fitted model.
A non-transitory computer-readable storage medium on which is stored computer-executable process steps for causing a computer to perform a method for estimating both of a surface roughness value and a sub-surface scattering property of a material, the method comprising:
- illuminating the material with a light beam with controlled coherence properties at multiple incident angles;
- recording multiple speckle patterns, each speckle pattern being recorded for a respective one of the multiple incident angles;
- and
- estimating both of a surface roughness value and a sub-surface scattering property of the material by calculations using the multiple speckle patterns and the incident angle for each such speckle pattern,
- wherein the estimating step comprises:
- calculating, for each of the multiple speckle patterns, a numeric value for a parameter;
- fitting the numeric values to a model, wherein the model defines relatedness amongst all of the parameter, surface roughness, the sub-surface scattering property, and the incident angle;
- and
- estimating both of the surface roughness value and the sub-surface scattering property of the material from the fitted model.
Dependencies are inferred from the claim text.