System and Method for Identifying Defects in a Material
AssigneeCognex Corporation
InventorXiaoguang Wang
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Abstract
Described are computer-based methods and apparatuses, including computer program products, for identifying defects in a material. A set of features is identified based on an image of a material, wherein each feature in the set of features is a candidate portion of a defect in the material. A set of chained features is selected based on the set of features, wherein each chained feature comprises one or more features that represent candidate portions of a same defect in the material. A defect in the material is identified based on the set of chained features and the image.
Claims12
A computerized method for identifying a defect in a material, comprising:
- generating, by a computing device, a preprocessed image based on an original image of a material;
- dividing, by the computing device, the preprocessed image into a set of sub-images;
- for a first sub-image in the set of sub-images:
- determining, by the computing device, whether the first sub-image includes a feature, wherein the feature is a candidate portion of a defect in the material;
- and
- if the first sub-image includes the feature, adding, by the computing device, the first sub-image to a set of feature sub-images;
- selecting, by the computing device, a chained feature based on the set of feature sub-images, wherein the chained feature comprises one or more features that represent candidate portions of a same defect in the material;
- and
- identifying, by the computing device, a defect in the material based on the chained feature and the original image, comprising calculating a remaining portion of the defect based on the chained feature,
- wherein identifying the defect comprises:
- selecting a pair of chained features comprising the chained feature;
- and
- determining if the pair of chained features satisfies a first criterion indicative of the pair of chained features being on a same defect in the material.
A computer program product, tangibly embodied in a non-transitory computer readable medium, the computer program product including instructions being configured to cause a data processing apparatus to:
- generate a preprocessed image based on an original image of a material;
- divide the preprocessed image into a set of sub-images;
- for a first sub-image in the set of sub-images:
- determine whether the first sub-image includes a feature, wherein the feature is a candidate portion of a defect in the material;
- and
- if the first sub-image includes the feature, add the first sub-image to a set of feature sub-images;
- select a chained feature based on the set of feature sub-images, wherein the chained feature comprises one or more features that represent candidate portions of a same defect in the material;
- and
- identify a defect in the material based on the chained feature and the original image, comprising calculating a remaining portion of the defect based on the chained feature,
- wherein identifying the defect comprises:
- selecting a pair of chained features comprising the chained feature;
- and
- determining if the pair of chained features satisfies a first criterion indicative of the pair of chained features being on a same defect in the material.
An apparatus for identifying a defect in a material, comprising:
- a preprocessing module configured to generate a preprocessed image based on an original image of a material;
- a strong feature detection module in communication with the preprocessing module configured to:
- divide the preprocessed image into a set of sub-images;
- and
- for a first sub-image in the set of sub-images:
- determine whether the first sub-image includes a feature, wherein the feature is a candidate portion of a defect in the material;
- and
- if the first sub-image includes the feature, add the first sub-image to a set of feature sub-images;
- and
- a weak feature detection module in communication with the strong feature detection module configured to:
- select a chained feature based on the set of feature sub-images, wherein the chained feature comprises one or more features that represent candidate portions of a same defect in the material;
- and
- identify a defect in the material based on the chained feature and the original image, comprising calculating a remaining portion of the defect based on the chained feature,
- wherein identifying the defect comprises:
- selecting a pair of chained features comprising the chained feature;
- and
- determining if the pair of chained features satisfies a first criterion indicative of the pair of chained features being on a same defect in the material.
Dependencies are inferred from the claim text.