Analysis of the rotational center location method in Optical Projection Tomography.

In Optical Projection Tomography (OPT), if the rotational center deviates from the central line of the image and this offset is not corrected during the reconstruction, serious blurring will happen in the final 3-dimensional (3D) result. Therefore, the high-precision rotational center location method is very important for OPT. However, existing methods are inconvenient because they need active participation during the location process. Thus, the automated and fast rotational center location method is in great demand. In preliminary work, we proposed an automated rotational center location method which consisted of a high Specimen Signal Intensity (SSI) sinogram selection and a coarse-fine search. Our method had an accuracy of about 1/4 pixel. However, further robustness analysis of our method is lacking. In this paper, we have investigated its location errors on sinograms with various SSIs and analyzed whether it was effective to use high SSI sinograms for rotational center location. Moreover, we have also discussed the relationship between location errors and the starting rotational angles. The experimental results showed that our coarse-fine method was robust under different starting angles. Meanwhile, the high SSI sinogram selection scheme improved the location precision.