Robust laser-stripe sensor for automated weld-seam-tracking in the shipbuilding industry

Using active contour models for feature extraction in camera-based seam tracking of arc welding

“…Due to the complex nonlinear process of arc welding and the lack of sensors which can extract sufficient information of weld process for control, most arc welding robotics are not equipped with a close-loop control system. Due to the limitations of the traditional sensors such as Xray radiation, ultrasonic, etc, used in the welding industry today, non-contact camera-based sensor systems have been attracting more and more researchers [1], [2], [3].…”

Real-time flatness inspection of rolled products based on optical laser triangulation and three-dimensional surface reconstruction

“…Center of mass is the method that provides the best results in laser stripe detection, 28,29 but when applied to an image, it assumes that the laser stripe must be found in each column. In industrial environments, this assumption is not reasonable because surrounding light, uneven surfaces, or laser degradation ͓see Fig.…”

“…27 The laser profile in each signal corresponds to a Gaussian profile, and thus, the laser center should correspond to the point of the signal with maximum luminance. The most common laser stripe extraction methods, 28,29 such as Gaussian approximation, center of mass, linear approximation, Blaix and Rioux detector, and parabolic estimator, provide the position of the center of the laser with subpixel precision, but they are highly affected by noise. Under controlled conditions, these methods provide a continuous stripe.…”

Visual Control System for Robotic Welding

“…Some algorithms such as multi-peak method and centre of gravity (Haug & Pristrchow, 1998), gradient detection and average of upper edges and the lower edges in Section 4 are all effective (a) (b) for the task. In order to get high quality profiles of seams, a method that combines smoothing filter, maximum detection and neighbourhood criteria is proposed.…”

“…Structured light vision is regarded as one of the most promising methods because of its simplicity, higher accuracy and good performance in real-time (Wu & Chen, 2000). Many researchers pay their attention to it (Bakos et al, 1993;Zou et al, 1995;Haug & Pristrchow, 1998;Zhang & Djordjevich, 1999;Zhu & Qiang, 2000;. For example, Bakos established a structured light measurement system, which measurement precision is 0.1mm when the distance is 500 mm.…”