1. A method of pattern discrimination in a pattern inspection apparatus of the type having a light source for illuminating an object to be inspected, a video camera effective to produce an electrical signal corresponding to said object, and a pattern discrimination system for comparing data from said electrical signal with standard data memorized from a standard subject of a type to be recognized to determine whether said object is of the same type as said standard subject comprising the steps of: setting a first threshold A for determining whether or not said data from said electrical signal contains characteristics sufficiently close to said standard data to judge said object to be of the same type as said standard subject; setting a second threshold B smaller than said first threshold A for determining whether or not said data from said electrical signal contains characteristics sufficiently close to said standard data to judge said object to be substantially identical to said standard subject; determining a difference between said characteristics of said data and said standard data; producing a match signal if said difference is less than said first threshold A; and replacing said standard data with said data if said difference is less than said second threshold B.