Study On On-line Detection Device And Its Calibration Method For H-Shaped Steel

In the cutting process of steel, the measurement for steel key positions offset is the very important step. This paper studies on the measurement method for steel section shape in the field, which has the important meaning and practical application value for cutting steel.The object section contour measurement technology based on line structured light is one of the most practical non-contact 3D measurement technologies commercially at present. It has many advantages, such as simple principle, high precision, easy to obtain the optical strip images and realize automation during measuring process etc. Computer vision based on line structured light is adopted to realize non-contact measurement of H-shaped dimensions.The main research contents involve four parts as following:1. According to the measurement requirements from the user, the steel parameters needed to be measured are given.2. Design the image processing for the industrial field. It includes image pre-processing, target point extraction and line identification and thinning algorithms, and gives the effect on various image processing steps.3. In this paper, the direct linear transformation (DLT) calibration method is used for system calibration. Calibration results are verified after system calibration. And the deviation analysis of system is given.4. According to the demand of improving measurement speed, this paper proposes a design program for hardware image processing system based on FPGA. This program includes the overall system design, circuit board schematic design and PCB drawing.Using VC for image processing, through field debugging verifying, the measurement for target points offset of steel section is completed. Measurement accuracy conforms to the industrial allowable range.