A real time quantum well hall effect 2D handheld magnetovision system for ferromagnetic and non-ferromagnetic materials non-destructive testing

A real time high sensitivity 16×16 sensor array magnetovision system prototype based on Quantum Well Hall Effect (QWHE) [1] sensors has been designed and built. This magnetovision system prototype, which is capable of measuring both ferrous and non-ferrous materials, has a spatial resolution of 40.6 point per inch (with software interpolation) giving excellent resolution for identifying shapes of objects under tests. A minimum detectable magnetic field of 1.8 ?T and a dynamic range of 84 dB can be achieved in this system due to the highly sensitive QWHE sensors. This prototype can be operated with a magnetic field frequency range from DC to 300 Hz. With an integrated pancake coil to supply the bias magnetic field, no extra electromagnet or coils are required for illumination during operation. A MATLAB based software with a graphical user interface was also developed for processing and displaying the captured data. The visualised inspection results are displayed as 2-dimensional graphs with different colour depths representing the strength of measured magnetic fields. With the visualised inspection results, better inspection efficiencies and accuracies can be achieved compared to traditional metal detectors.