When scanning a relatively high resolution, thick object using conventional computed tomography (CT), the scanning axis of the X-ray gantry and detector is approximately perpendicular to the rotation axis of the sample. However, the inner interconnections in flat 3D devices are not reconstructed correctly in regular circular CT. In this paper, we focus on 3D tomographic reconstruction of inner interconnections by CT with particular attention to off-centered circular trajectory CT. However, in off-centered circular trajectory CT, the limited tilting angles of projections result in a missing wedge artifact because the object cannot usually be tilted beyond the limit and the data in the remaining projections are not obtained. Therefore, to alleviate missing wedge artifacts, we propose a reconstruction scheme of combining by filtered back projection (FBP) and constraint-based total variation minimization (c-TVM). In the c-TVM method, the artifact of missing wedge is minimized and the reconstructed region is suppressed with high frequency details while leaving the boundaries between homogeneous regions. In our experiments, the CT system obtained the projected images from a rotating sample using a fixed-mounted X-ray source and detector. We acquired 400 rotational projection images of a vertical connection in an off-centered circular trajectory with 30° tilting angles. We then reconstructed the aligned 3D views of the sample. Finally, we demonstrated that the proposed FBP and c-TVM combination with iterative processing yields a superior 3D reconstruction model to conventional tomography.
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