1. A method of setting up an automatic defect classifier system for classifying semiconductor defects, the method comprising: providing defect image data for a plurality of defects; selecting a representative set of defects from the defects so as to optimize manual classification; and presenting the representative set of defects and not the defects which are not part of the representative set to a user for manual classification, wherein the defects which are not part of the representative set are defined as non-reviewed defects.