1. In probe-based pattern matching, a method for synthetic training of a model of a pattern, the method comprising: providing a machine vision system that includes a processor that is programmed to perform the steps of: placing a plurality of positive probes at selected points along a boundary of the pattern; providing at least one imaginary straight segment parallel to a segment of the boundary of the pattern; placing a plurality of negative probes at selected points along the imaginary straight segment, each negative probe having a negative weight.