1. A substrate inspection method, comprising: providing at least two images of one or more sample substrates, each of said sample substrates having one or more dies thereon and each of said dies having a plurality of patterns thereon; identifying, from said images, a target pattern which occurs two or more times in said images, wherein said target pattern occurrences are located on one or more of said dies; and comparing said target-pattern occurrences against each other to determine, from said images, a presence of abnormalities in said target-patterns occurrences, thereby determining a presence of one or more defects in said target-pattern occurrences.