Improving the Optical Inspection of Through Hole Resistors With Additional Spectral Illuminations

Through hole technology is still playing an important role in the manufacturing of electronics. Thus, there is the need for reliable and contemporary automatic optical inspection of such components. The resistor as one of the most common parts challenges the optical inspection with its colored rings encoding its resistance value. The current approach to inspecting these components is discussed and its drawbacks are shown. A new approach is presented using the comprehensive illumination options available to modern automatic optical inspection machines. To test the new method a dataset of real inspection data was collected. The applicability of the new approach is shown by training a neural classifier with the data and comparing it to the formerly used method.