May 21 st – 23 rd 2014, Brno, Czech Republic, EU OPTIONS FOR MEASURING PARAMETERS OF SURFACES IN METALLURGY WITH EXPLOITATION OF OPTICAL METHODS Jan DUCHÁČEK, Milan HEGER, Ondřej ZIMNÝ, Roman MECA, Ivo ŠPIČKA VŠB-Technical university of Ostrava, Czech Republic duc033@vsb.cz, milan.heger@vsb.cz, ondrej.zimny@vsb.cz, mec069@vsb.cz, ivo.spicka@vsb.cz Abstract There exists a lot of technologies in metallurgy, which need to know certain specific parameters of surface of processed materials or tools. Usually these parameters are acquired by mechanical methods, but these methods can be successfully replaced by exploitation of active optical methods as well as passive optical methods. In the paper are presented some of the approaches of exploitation of optical methods for acquiring the global and local parameters of surface. As an example can be used the monitoring of degradation of operational areas of production tools and devices or quality of surface of produced product. For the most of the active optical methods were used laser beam devices in combination with methods of image analysis. These methods enable acquire 3D information about monitored surface. By processing these informations could be acquired entire relief of monitored surface as well as localization of important surface anomalies. Keywords: Computer Vision, Laser, 3D Surface, Image Processing 1. INTRODUCTION Quality of surfaces of products and production tools, which more or less influence the final quality, are in the lots of the metallurgical technologies one of the most important of monitored parameters. One of the options, how to monitor the surface quality of solid objects is exploitation of optical methods, when usually is the monitored surface alight by laser device and then is captured the image of alight scene and used image processing methods. After image processing we acquire the important features of captured scene from the image and these features are subsequently analyzed by mathematical methods, which allow to acquire 3D information about captured part of the monitored object. Acquired information by these methods along with required technological parameters of the surface allow us to detect such a differences, which exceeds required limits. This will allows to decide whenever the products or tools are still usable for acquiring of the desired standards of quality and technology. Even though there exists a lot of areas in metallurgy, where could be possible this approach implement, for purpose of this paper was chosen as an example the application for quality detection on surface of crystallizer. In this case is possible to watch both important parameters. One of them in entire shape of surface of crystallizer’s plates (global parameter) and second one is the quality of surface itself (local parameter). 2. SCENE ALIGHTING AND CAPTURING When are the active optical methods exploited, then principles of active triangulation [1] are used. Active triangulation uses knowledge about mutual position of laser device and capturing camera. Laser device is alighting scene with laser beam formed in the shape of line. This line is captured by camera, which is firmly placed towards laser device. The color of the laser beam has to be selected regarding the temperature or the color of the object in the time of measuring. Next important factor is performance of laser device, which has to be selected based on intensity of alighting of neighborhood of the captured scene, reflectance of the material and distance from targeted object. Important factors with influence on measuring quality are camera