New technique for 2D and 3D X-ray image restoration of pipes in service given a limited access for observation

Regular Computer Tomography (CT) is basically a routine procedure for the reconstruction of nearly cylindrical-symmetric objects like pipes if full access around the object is available for data acquisition. But for many practical tasks as for pipe inspection, the access to the object and the applicability of complex equipment, usually used for CT, are strongly limited. On the other hand, the importance of accurate wall thickness measurements is increased to ensure the safe operation of aging pipes and constructions in different industry sectors like chemical or power engineering industry. Two different techniques respectively for 2D and 3D image restoration of the inner profile of pipes are proposed to solve the stated ill-posed problem. The presented techniques yield iterative procedures considering prior information in the reconstruction algorithms. The prior information is introduced in a general and non-preconceived form and not oriented on the unknown image features. The feasibility of the developed...