HIGH RESOLUTION 2D MAGNETIC VISION- B-Cam

An electric current generates a magnetic field. In metal structures, imperfections in the structure such as cracks or material flaws show up in the field pattern generated when current flows in the structure. If the current is changing, the field may be detected as a voltage in a pickup coil. However pick-up coils are bulky and it is impractical to assemble an array of coils that could sense a field pattern over an appreciable area of space in proximity to a structure under test. For this reason, magnetic field testing is not used for sub-sea structures and in general is confined to laboratory use.

There is a semiconductor alternative to using sensing coils, called a Hall Effect device. We have a technology which can make these devices as sensitive as coils in the context of field mapping. They have a huge advantage in that they respond uniformly to fields of all practical frequencies, while coils no not.

The semiconductor technology makes it practical to produce a camera which can see a magnetic field pattern over an appreciable area. The camera would need a sophisticated current generator to excite the structure. This can be thought of as akin to illuminating the scene. Such a camera would be a major step forward in checking integrity of metal structures. It could be fitted to submersible vehicles and used to inspect pipelines and rig structures. It adds to safety in the Oil and Gas industry.

The project involves enhancing the sensitivity of a new type of extremely sensitive Hall Effect devices and building a prototype camera to demonstrate the power of the new technique. We expect it to generate a service industry in inspection and also to further materials research.