An easy way to achieve higher depth of field in a camera-laser configuration is to tilt the image sensor respect to the lens plane, such that the image plane, laser plane and the lens plane intersect in a unique line (Scheimpflug condition [1]). If something has to be measured with this kind of cameras, a proper camera calibration must be done. The usual calibration methods are not valid in this case because they are based on the pin-hole camera model, this model being valid only for normal cameras, i.e. cameras that have the image plane and the lens plane parallel. Thus, a new camera model and its respective calibration must be developed, which includes the Scheimplug angle in the intrinsic camera parameters. In this article, the new camera model and its calibration are defined. Experimental results indicate that using this calibration cameras under Scheimpflug condition can be accurately calibrated.

No abstract

The roll forming process is a very interesting process for the production of profile shaped parts because of its high production rate, low investment and efficient use of the material. However, as in most of the manufacturing processes, the set up of the machine is very important for the quality of the profiles to be manufactured being the traditionally used trial and error method high time and scrap consuming. Within the set up, one of the most important variables to be defined is the right gap or distance between the upper and the lower roll at each station. This gap can lead to, or avoid, the appearance of geometrical errors such as differences in springback effect or longitudinal bow of the final profile. Furthermore, to find the correct gap between the rolls,a traditional tedious and costly work must be made based on a trial and error methodology. Different sensor based methodologies have already been implemented successfully in other forming processes. The present work aims at evaluating if force and torque measurements are a viable solution to decrease the roll forming process set-up time. This way, the effect of the gap for three different materials, a DC01, DP600 and MS1200 steel, has been analyzed. For this purpose, force and torque measurement together with final geometry measurements have been made at different gap configurations. A correlation between the profile quality and the process variables has been carried out in order to identify the influence of the gap at the setting up of the machine.