Development of trinocular CCD-based optical detector for real-time monitoring of laser cladding

Real-time measurements of clad geometry is an essential control signal for the closed-loop control of laser cladding (laser solid freeform fabrication) process. The measurement of clad geometry in real-time by vision-based detectors is a challenging task due to relative position of clad melt pool and the detectors and intensive image processing. In this paper, the development of a novel trinocular optical CCD-based detector for measuring clad geometry is discussed. An algorithm, including a fuzzy adaptive threshold strategy, a perspective image projection method, and a simple but realistic strategy for analyzing the projected images is developed to extract the clad height, clad width and rate of solidification in real-time.