Image processing device, measuring/testing system, and program
View Patent ↗The present invention provides a contour extraction technique capable of resolving not only spuriousness, duplication, or branches in the contours of a sample pattern, but also discontinuities in the contours. A thinning process is performed with respect to design data for generating a sample pattern, and pattern in/out definition information defining the inside and outside of a pattern formed on a target sample is generated. Then, based on the Marker Controlled Watershed Segmentation method, region segmentation is performed by expanding regions indicated by the pattern in/out definition information while referencing pixel values of an edge-enhanced image of a target sample image, and pattern contours are generated.
1. An image processing device that extracts a contour of a pattern formed on a sample that is a target of measurement or testing, the image processing device comprising:
a pattern in/out definition information generation unit that performs a thinning process on design data for generating a target sample so that inside and outside regions of the pattern are narrowed and generates pattern in/out definition information defining an inside and an outside of a pattern formed on the target sample and generating the pattern in/out definition information by referencing alignment information obtained through a matching process between the target sample image and the design data;
an edge enhancement unit that generates an edge-enhanced image of a target sample image obtained by irradiating the target sample with an electron beam; and
a contour generation unit that performs region segmentation by expanding regions indicated by the pattern in/out definition information while referencing pixel values of the edge-enhanced image and generates a pattern contour of the target sample.
2. The image processing device according to claim 1 , wherein the contour generation unit performs the region segmentation by expanding the regions indicated by the pattern in/out definition information in such a manner that a region of the inside of the pattern overlaps with an edge part indicated by the edge-enhanced image.
3. The image processing device according to claim 2 , wherein the contour generation unit performs the region segmentation based on a Marker Controlled Watershed Segmentation method.
4. The image processing device according to claim 2 , wherein the contour generation unit generates the pattern contour of the target sample by executing an active contour extraction process using, from the pattern in/out definition information, external energy indicating a pattern interior region and external energy indicating a pattern exterior region.
5. The image processing device according to claim 1 , wherein the pattern in/out definition information generation unit generates the pattern in/out definition information by performing a peeling process on an image of an interior region and exterior region of the pattern with respect to the design data.
6. The image processing device according to claim 1 , wherein the pattern in/out definition information generation unit references alignment information obtained through a matching process between the target sample image and the design data, morphs the design data in such a manner that the design data envelops the target sample image, and generates the pattern in/out definition information from the morphed design data.
7. The image processing device according to claim 1 , wherein the edge enhancement unit performs a plurality of filter processes on the sample image, and generates the edge-enhanced image by combining respective filter processed images.
8. A measuring/testing system comprising:
an electron microscope device that generates a target sample image from information obtained by irradiating, with an electron beam, a sample that is a target of measurement or testing; and
the image processing device according to claim 1 .
9. A non-transitory computer readable medium that stores a program for causing a computer to function as the image processing device according to claim 1 .