Patent ID: 8149409

Claim:
An on-line detection system for a weld of a steel strip comprising: reflectivity measuring means for emitting a laser beam onto a moving steel strip and continuously measuring a reflectivity of the laser beam returning from a surface of the steel strip; and signal processing means for detecting the weld of the steel strip based on change in a reflectivity measured on the weld, wherein the reflectivity measuring means includes: a laser beam generator for generating the laser beam; a focusing lens for focusing the laser beam; a collecting lens for collecting the laser beam reflecting from the surface of the steel strip; a light detector for outputting an electric signal corresponding to a reflectivity of the collected laser beam; and a beam adjuster for adjusting a cross section of the laser beam generated by the laser beam generator, wherein the signal processing means adjusts a weld-determining signal level and a weld-determining time interval according to a welding type.