Weld pool surface depth measurement using a calibrated camera and structured light

Automated monitoring and control of the weld pool surface has been one of the goals of the welding industry. This paper presents a technique which uses a calibrated charge-coupled device (CCD) sensor and structured light to extract the surface information as depth of pool from captured images. It projects a laser line from a pre-determined position onto the specular weld pool surface. A reflected laser beam from the specular surface is captured by a calibrated CCD sensor to form the image. The image is then processed based on the ray-tracing technique to calculate the depth of the weld pool surface using the position of the laser and its fan angle along with the intrinsic parameters and extrinsic parameters of the CCD sensor.