Comparative Study of Traditional Depth Estimation Algorithm and Fast EPI Algorithm on the Influence of Longitudinal Resolution in 3D Dose Measurement System

The three-dimensional dosimetry system composed of tissue equivalent scintillation material and light field camera can accurately measure the three-dimensional dose distribution information of protons or heavy ions in tissue equivalent materials, and provide a more accurate reference for dose estimation in radiotherapy. The flicker information produced by the deposition energy of protons or heavy ions in the tissue equivalent material is captured by the light field camera, and the three-dimensional distribution information of the protons or heavy ions in the tissue equivalent scintillation material is obtained by using the depth estimation algorithm. The depth estimation algorithm has a great influence on the longitudinal resolution, and then affects the accuracy of the three-dimensional dose distribution information. In this paper, firstly, the plane distribution image of flashing light is obtained by light field camera, and then the effects of traditional depth estimation algorithm and fast EPI (epipolar plane image) algorithm on the longitudinal resolution of the image are compared and analyzed. Finally, according to the comparative experiment, it is concluded that in the three-dimensional dosimetry system, the traditional depth estimation algorithm considers the depth information from the point of view of the correlation between the sub-image blocks. Compared with the fast EPI algorithm which calculates variance through displacement change from EPI sequence, the traditional depth estimation algorithm can obtain better longitudinal resolution of the image.