1. A substrate inspection method, comprising: providing one or more images of one or more sample substrates, each of said sample substrates having one or more dies thereon and each of said dies having one or more 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.