Correct Block Artifacts by Differential Projection for Dynamic CT System
Yongshun Xiao 1,2*, Fangda Han 1,2, Wei Feng 1,2, Daiwei Yu 1,2
1 Department of Engineering Physics, Tsinghua University, Beijing, 100084, China
2 Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, China
In aero-engine industry, it is meaningful to make regular and effective tests for engines in service. However, current detection methods often have problems like limitation to materials characteristics or geometry structures. Recently, a novel Dynamic CT System is proposed to provide high efficient CT inspection for the rotating parts, especially the blades of aero engine in operation. However, one problem exists in the proposed system is that some components remain static when the engine is in operation, these static parts will appear as strip artifacts in projection and finally ring artifacts in the reconstructed image, which are called block artifacts. In this paper we put forward the Differential Projection Correction method to correct the block artifacts and reconstruct the blades of the aero engine. The method makes use of the distribution of the blades and the static parts to remove the artifacts. The experiment results show that the proposed method can effectively remove the block artifacts while maintain the grayscale and geometry structure of the blades, furthermore, we also verify its ability of defect detection by numerical experiments. The Differential Projection Correction method makes the system more practicable for in-situ inspection of aero engine.
Keywords non-destructive testing, field detection, rotating parts, differential projection
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