Transparency Quantification. Application to Composite Materials Quality Controls by Image Processing

A piece in composite material is composed of a frame, or reinforcement, in fibres put together with a resin. The quality of such a piece depends directly on the quality with which the resin penetrates the fibres of the frame. So it is interesting to be able to quantify the evolution of the impregnation quality during the fabrication. This article and the quality controls it describes concern glass fibres reinforcements. At the beginning and without resin, this kind of reinforcement is white and opaque. It becomes transparent as the impregnation by the resin increases. A good way to quantify the impregnation level is to correlate it to the transparency level. For this purpose, we take images of the material during the manufacturing phase, and we treat each of them to extract an impregnation level. This operation will give us impregnation curves.