| ABSTRACT: | AN IMPROVED CONE-BEAM FILTERED BACKPROJECTION RECONSTRUCTION
ALGORITHM BASED ON X-RAY ANGULAR CORRECTION AND MULTIRESOLUTION
ANALYSIS
S. Yi, H. Ying, and S. Hongyu
Dalian University of Technology, Dalian, Liaoning Province, China
With the extensive application of industrial computed tomography in the field of non-destructive testing,
how to improve the quality of the reconstructed image is receiving more and more concern. It is well known
that in the existing cone-beam filtered backprojection reconstruction algorithms the cone angle is controlled
within a narrow range. The reason of this limitation is that the variation of X-ray angle can not be corrected.
Thus the size of the tested workpiece is limited. Considering the characteristic of X-ray cone angle, an
improved cone-beam filtered back-projection reconstruction algorithm taking account of angular correction
is proposed in this paper. The aim of our algorithm is to correct the error resulted from the limitation of X-
ray cone angle in the conventional algorithm. The basis of the correction is the angular relationship among
X-ray source, tested workpiece and the detector. Thus the cone angle is not strictly limited and this
algorithm may be used to detect larger workpiece. Further more, adaptive wavelet filter is used to make
multiresolution analysis, which can modify the wavelet decomposition series adaptively according to the
demand for resolution of local reconstructed area. Therefore the computation and the time of reconstruction
can be reduced, and the quality of the reconstructed image can also be improved.
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