Classification of Impedance Traces

In the field of electronic fault detection much of the evaluation is performed by a human operator using a visual inspection system. One such system displays the current versus voltage (I-V) characteristics, referred to as the impedance trace, of the electronic component under test. The shape of the impedance trace indicates the integrity of the component. The subjectivity and poor repeatability of the visual inspection have been identified as major deficiencies in the existing systems. A microprocessor-based system has been proposed to store and provide a quantitative classification of the impedance traces. The primary objective of this system is to provide an efficient automated system for classifying the impedance traces of different electronic components. Thus three trace representations and two classification schemes are proposed, based upon techniques developed in the field of pattern recognition. An experiment contrasts the different classification approaches. A Fourier series representation, combining both magnitude and phase features, was determined to provide the best overall performance when used in conjunction with a developed distance measure.