“…Thanks to its high speed, low costs, and effectiveness at capturing defects on various surfaces, multi-illumination systems are widely used today in the industry. Applications include detecting casting defects on steel and other metallic surfaces [7,9,11,12,21,26], cracks in paintings [4,16], connection defects in electronic circuit boards [23], or quality control of carbon-fiber materials [18]. Due to the widely varying reflectance properties of the materials involved, defect detection techniques vary substantially in terms of their algorithmic steps.…”