DEFECT DETECTION METHOD IN HETEROGENEOUSLY TEXTURED SURFACE

摘要

According to another aspect of the present invention, a defect detecting method of an uneven texture surface includes the following steps of: dividing a reference image which has no defect into a plurality of reference patch images; making the plurality of reference patch images binary-coded and calculating reference specific vectors from the binary-coded reference patch images; generating a model parameter of a Gaussian mixture model using a set of the reference specific vectors; dividing an inspection image about an inspection object into a plurality of inspection patch images; making the plurality of inspection patch images binary-coded and calculating inspection feature vectors from the binary-coded inspection patch images; calculating the log-likelihood of each inspection patch image by applying the inspection feature vectors to the model parameter; and comparing the calculated log-likelihood with a log-likelihood threshold value, and determining that a patch image having a value lower than the log-likelihood threshold value has a defect.