Rotational angle measurement for computed tomography of living single-cells

We performed a spectroscopy-tomography study of a single living cell to measure slight changes in its protein[1]. This technique, which combines high-spatial-resolution spectrometry with precise single-cell rotation, can obtain 3-dimensional distribution of proteins in high spatial resolution in real time. Rotational velocity measurement is necessary to learn the rotational direction and angle of the cell, information that is required for precise rotation. So, we propose an optical spatial filtering method for measuring the rotational angle of a low-contrast object. This proposed method derives the arbitrary component of the spatial frequency from the random refraction index distribution. In this report, we've tried to examine the proposed method using non-labeled cell. The complex distribution of refraction index is modeled by liquid crystal as the artificial non-labeled cell. We discuss the velocity vector measurement results, and the observation results of a single living human cell.