The overall aim of the project is to develop and to test in industrial conditions a pilot system based on advanced optical and non-contact ultrasonic techniques able to characterise on-line the weld quality as well as to improve the control of laser welding. The techniques will be applied in two cases: coil joining at the entry section of a rolling mill and tailored blank production. Moreover, it is intended to develop a model allowing to set criteria in order to decide whether the weld quality is sufficient or not with regard to the service requirements of a rolling mill.