Geometric Reconstruction and Measurement of Long Steel Products Using 3-D Sensors in Real Time

Calibration, registration, reconstruction, and measurement are the fundamental tasks required for the inspection of dimensions in long steel products. Calibration is performed offline. The rest of the tasks are performed repeatedly while the long steel product ismoved under 3-D reconstruction sensors. This study proposes robust methods for the reconstruction of long steel products. In addition, measurement procedures for some representative dimensions are presented. Three different reconstruction procedures are proposed-reconstruction based on geometric primitives in the model of the product, reconstruction based on local fitting, and reconstruction based on piece wise linear approximation. Tests on synthetic on real data indicate excellent performance in terms of computational costs and measurement accuracy. Conclusions also provide recommendations for the application of the proposed reconstruction procedures depending on whether a model is available or not, and the type of features that need to be calculated for the long steel products.