Method for generating three-dimensional shape information of object to be measured, defect detection method, and defect detection device

Abstract

This application relates to a method of generating three-dimensional (3D) shape information of an object to be measured from an image including intensity information of an object hologram generated by interference between a reference light reflected from an optical mirror and an object light affected by the object. In one aspect, the method includes checking at least one frequency component included in the image and extracting real image components corresponding to a real image from the frequency component. The method also includes generating a correction light and a real image hologram based on the real image components, generating an intermediate hologram based on the correction light, and generating curvature aberration correction information from the intermediate hologram. The method further includes generating a correction hologram based on the curvature aberration correction information and generating the 3D shape information of the object from the correction hologram.

What is claimed is: 
     
         1 . A method of generating three-dimensional (3D) shape information of an object, the method comprising:
 acquiring an image including intensity information of an object hologram generated by interference between a reference light reflected from an optical mirror and an object light affected by the object;   extracting real image components corresponding to a real image from the at least one frequency component included in the image;   generating a correction light and a real image hologram based on the real image components, the correction light being in a conjugate relation with the reference light and the real image hologram including real image information of the object;   generating an intermediate hologram based on the correction light, the intermediate hologram resulting from removing information of the reference light from the real image hologram;   generating curvature aberration correction information from the intermediate hologram;   generating a correction hologram based on the curvature aberration correction information, the correction hologram resulting from removing an error caused by a curvature aberration from the intermediate hologram; and   generating the 3D shape information of the object from the correction hologram.   
     
     
         2 . The method of  claim 1 , wherein the generating of the curvature aberration correction information includes:
 generating 3D shape information of the object from the intermediate hologram;   determining at least one parameter based on the 3D shape information of the object, which is generated from the intermediate hologram, the at least one parameter determining the curvature aberration correction information; and   generating the curvature aberration correction information based on the at least one parameter.   
     
     
         3 . The method of  claim 2 , wherein the 3D shape information of the object, which is generated from the intermediate hologram, includes at least a portion of a curved surface of a hemispherical shape, and
 the determining of the at least one parameter includes:   determining coordinates of a center of the curved surface of the hemispherical shape from the at least portion of the curved surface of the hemispherical shape; and   determining a radius of the curved surface of the hemispherical shape from the at least portion of the curved surface of the hemispherical shape.   
     
     
         4 . The method of  claim 3 , wherein the determining of the at least one parameter further includes generating a cross-section cutting the curved surface of the hemispherical shape,
 the determining of the coordinates of the center includes determining the coordinates of the center from a curve generated on the cross-section by the curved surface of the hemispherical shape, and   the determining of the radius of the curved surface includes determining the radius from the curve.   
     
     
         5 . The method of  claim 4 , wherein the cross-section is parallel with a traveling direction of the object light. 
     
     
         6 . A system for generating three-dimensional (3D) shape information of an object, the system comprising:
 means for acquiring an image including intensity information of an object hologram generated by interference between a reference light reflected from an optical mirror and an object light affected by the object;   means for extracting real image components corresponding to a real image from the at least one frequency component included in the image;   means for generating a correction light and a real image hologram based on the real image components, the correction light being in a conjugate relation with the reference light and the real image hologram including real image information of the object;   means for generating an intermediate hologram based on the correction light, the intermediate hologram resulting from removing information of the reference light from the real image hologram;   means for generating curvature aberration correction information from the intermediate hologram;   means for generating a correction hologram based on the curvature aberration correction information, the correction hologram resulting from removing an error caused by a curvature aberration from the intermediate hologram; and   means for generating the 3D shape information of the object from the correction hologram.   
     
     
         7 . An apparatus comprising a processor configured to perform the method of  claim 1 . 
     
     
         8 . The apparatus of  claim 7 , further comprising an image sensor configured to acquire the image to be processed by the processor. 
     
     
         9 . A non-transitory computer readable recording medium storing instructions to perform the method of  claim 1 .