An automated foam decay measurement with image processing system

The decrease of the wear represents an economically interesting challenge in gear technology. Particularly, the property of viscous lubricants to absorb dispersed air, significantly affects, as a function of pressure and temperature, the friction and thus the wear of mechanical systems. In order to be able to meet quantified specifications about the quality of different oils in the real application, an experimental lab test for foaming has been developed. The metrological challenge consists in the localisation of the phase boundaries between liquid and foam and between foam and air. These permanently variable borders apparently result from the occurrence of two phases with different texture. Instead of a complex texture evaluation, closer consideration leads to a more robust and more efficient solution. The brightness profile along the foam column shows significant edges that correspond with the phase boundaries. The measuring task is solved with a compact image processing system.