BACKGROUND: Limited-angle problem occurs in many applications of X-ray
computed tomography (CT) and it will lead to artifacts.
OBJECTIVE: In this paper, we present the tomographic imaging of pipeline
which is in service by cone-beam computed tomography (CBCT). And our purpose
is to suppress the artifacts caused by the limited-angle problem.
METHODS: First, traditional helical scanning strategy is adopted for the
pipeline where can be fully scanned, and the slices with less or no defects
from the reconstructed image are selected to constitute the prior image.
Then a limited-angle reverse helical scanning strategy is developed for the
pipeline where can be scanned within limited angular range. Second,
considering the constraint of the prior image and the resemblance among
slices of pipeline, an image model which incorporates the Schatten
p(0<p<1)-norm penalty term is developed. Finally, split Bregman
algorithm based method is utilized to solve the model.
RESULTS: Numerical results show that our method is efficient and feasible in
suppressing artifacts and it is superior to popular methods when the angular
range is small.
CONCLUSION: The developed method is promising in suppressing the artifacts
in limited-angle problems, and it can be potentially used in pipeline
testing.
