Flatness Profile Computation
Three-dimensional surface reconstruction of a rolled product using slit scanners involves two separate stages: intraframe and interframe processing. Once a frame with the projection of the laser stripe onto the surface of the product is acquired, it must be processed in order to determine the surface profile. To this purpose, the intraframe processing is split up into three major tasks. The first task consists of extracting the laser stripe from the image and computing the strip profile expressed in the image coordinate system. The second task translates each point of the detected stripe to obtain the profile of the surface expressed into world coordinates. The third task involves software tracking to compensate for the effects of small lateral displacements while the strip is being processed. Figure 13 shows the steps carried out by the intraframe processing stage in order to compute the position of the fibers of the strip for each frame.