A Template Model for Defect Simulation for Evaluating Nondestructive Testing in X-Radiography

This paper proposes a new template model for the simulation of casting defects which are classified, according to shape, into three main types: the single defect with circular or elliptical shape, shrinkage defects with stochastic discontinuities, and the cavity or sponge shrinkage defects. For effective simulation, different nesting stencil plates are designed to reflect the characteristics of different casting defects. These include intensity, orientation, size, and shape. The proposed approach also uses geometric diffusion to demonstrate the production of simulated defects with effective shading and contrast when compared to their background. In order to evaluate the effectiveness of the proposed approach, the simulated casting defects are superposed on real radioscopic images of casting pieces and compared with real defects by extensive visual inspection. On the other hand, in order to verify the similarity of the simulated defects and the real defects, we have used our defect inspection algorithm to recognize both real and simulated defects in the same image. The experimental results show that the proposed defect simulation approach can produce a large range of simulated casting defects, which can be utilized as sample images to tune the parameters of casting inspection algorithms.