Method for determining a surface map and imaging system for same
AssigneeMitutoyo Corporation
InventorsBalasubrahmaniyam MUKUNDAKUMAR, Shimpei MATSUURA
Life of this patent
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Abstract
The invention relates to a method for determining a surface map, such as a height map, of a sample surface having a first region with a first reflectivity and a second region with a second reflectivity. The invention further relates to an imaging system for determining a surface map of a sample surface having a first region with a first reflectivity and a second region having a second reflectivity. The invention is further related to a digital data carrier including a computer program which, when run on a processor of an imaging system according to the invention, causes the imaging system to perform the method according to the invention.
Claims14
A method for determining a surface map of a sample surface having a first region with a first reflectivity and a second region with a second reflectivity, wherein the first reflectivity is different from the second reflectivity, wherein use is made of an imaging system for determining an image of the sample surface, wherein the imaging system has a focal measurement plane, wherein the method includes:
- determining that an image of the sample surface obtained with the imaging system is saturated when the sample surface is arranged in the focal measurement plane of the imaging system;
- arranging the sample surface in a defocused position at a distance Z from the focal measurement plane of the imaging system along an axis perpendicular to the focal measurement plane such that the image of the sample surface obtained with the imaging system is no longer saturated;
- obtaining a defocused image of the sample surface arranged in the defocused position with the imaging system;
- determining an infocus image by backpropagating the defocused image the distance Z by applying a backpropagation algorithm to the defocused image;
- and
- determining the surface map of the sample surface based on the infocus image.
An imaging system for determining a surface map of a sample surface having a first region with a first reflectivity and a second region with a second reflectivity, wherein the imaging system includes a processor, and wherein the imaging system is configured for determining an image of the sample surface, wherein the imaging system has a focal measurement plane, wherein the imaging system is configured for:
- determining that an image of the sample surface obtained with the imaging system is saturated when the sample surface is arranged in the focal measurement plane of the imaging system;
- arranging the sample surface in a defocused position at a distance Z from the focal measurement plane of the imaging system along an axis perpendicular to the focal measurement plane such that the image of the sample surface obtained with the imaging system is no longer saturated;
- obtaining a defocused image of the sample surface arranged in the defocused position;
- determining an infocus image by backpropagating the defocused image the distance Z by applying a backpropagation algorithm to the defocused image;
- and
- determining the surface map of the sample surface based on the infocus image.
A non-transitory computer-readable medium storing an executable set of instructions for determining a surface map of a sample surface having a first region with a first reflectivity and a second region with a second reflectivity, wherein the first reflectivity is different from the second reflectivity, wherein when executed by a computer processor of an imaging system for determining an image of the sample surface, the imaging system having a focal measurement plane, the set of instructions causes the computer processor to execute operations comprising:
- determining that an image of the sample surface obtained with the imaging system is saturated when the sample surface is arranged in the focal measurement plane of the imaging system;
- arranging the sample surface in a defocused position at a distance Z from the focal measurement plane of the imaging system along an axis perpendicular to the focal measurement plane such that the image of the sample surface obtained with the imaging system is no longer saturated;
- obtaining a defocused image of the sample surface arranged in the defocused position with the imaging system;
- determining an infocus image by backpropagating the defocused image the distance Z by applying a backpropagation algorithm to the defocused image;
- and
- determining the surface map of the sample surface based on the infocus image.
Dependencies are inferred from the claim text.