This article describes an innovating measuring device to continuously assess the powder coverage on the whole surface of the mould in a continuous casting process. The measurement is based on the use of a thermal imager device moved along the mould. With adequate translation and rotation of the camera, it is possible to view up to 72 % of the surface of the mould. A dedicated program for images acquisition and processing displays coloured maps of the mould on which areas with poor powder coverage are clearly highlighted. With this technique, the control of the powder addition in a closed loop way, by using the analysis of the image, is possible.