A method, apparatus, system, computer program and medium, for inspecting a wide variety of circuit boards. A controller generates test data and reference data according to characteristic information of a circuit board. Using the test data, the circuit board generates processed data. A comparator compares the processed data with the reference data on a bit-by-bit basis. Based on the comparison result, the comparator determines acceptability of the circuit board. In addition, the comparator is capable of specifying a specific portion of the circuit board causing a defect.