A three dimension reconstruction method on a kind of micro and thin laser seam

The laser weld is becoming more and more popular in the steel industrial production. However, the varying illumination, reflection and splatter lead to the irregular seam shape, which deteriorates the seam quality. In order to evaluate the seam shape and its quality, a 3D reconstruction method about micro and thin laser seam is proposed. The line structured light stripe is projected on the laser seam to be measured by a projector, and deformation of the stripe is captured by a CCD camera with industrial microscope lens. An image processing method that can efficiently locate the deformation of the stripe in the image plane is presented. Also, a novel procedure to automatically define the region of interest in the image is proposed. And then a straight line and curve fit is used to reduce the harm of the various disturbances and accurately gain the centre line of stripe. Furthermore, the characteristic points of the seam are obtained by using the distance search method. Finally, the proposed reconstruction method is applied to laser seam specimen, the desired performances are gained, and the results are satisfying.