Feature points extraction of different structure for industrial computed tomography image contour

In order to accurately obtain the physical structure and dimension, the feature points extraction must be carried out from the ICT (industrial computed tomography) image contour. Therefore, the discrete data could be transformed into CAD models, and different methods have been developed for the feature points extraction, according to geometric features, the function and shape of mechanical parts. We discussed the feature points extraction methods, and one method is not enough to all the structures, so we must first distinguish the structure as regular and irregular. For the regular structures, by using a positive–negative factor, the curvature estimation method was improved. This method was designed and verified for the actual part, and has an improved accuracy in the feature points extraction. While for the irregular structures we used the polygon approximation method in the feature points extraction. For a complex part composing of several regular structures and irregular structures in the same ICT contour, we divided the whole contour into the regular and irregular structures, then used the corresponding methods for each structure. Last all feature points were extracted. The actual examples showed that the used methods are practical and effective.