Image capturing system and a method for determining the position of an embossed structure on a sheet element

An image capturing system for determining the position of an embossed structure on a sheet element, wherein the sheet element is moved through a viewing area, the system comprising:

• a camera configured for capturing a line image of the surface of the sheet element in the viewing area, and an illumination unit comprising a plurality of light sources, each light source being configured for illuminating the viewing area to generate a respective line image across the viewing area that is captured by the camera;
• the light sources being arranged at respective different inclinations with respect to the viewing area;
• and
• an image evaluation unit configured to receive the line images from the light sources captured by the camera, configured to determine intensity of reflected light from each light source for each location in the viewing area, configured to construct an intensity profile based on the intensities of reflected light from the light sources for each location in the viewing area, and configured for determining an inclination-related parameter for each location of the surface of the sheet element in the viewing area and across the viewing area based on the intensity profile.