Acquiring and Processing of Light Field Images in a Tissue Equalent Scintillator Based on 3D Dosimetry

In recent years, the 3D dose measurement technology based on light field imaging of scintillation light in the field of dynamic radiation therapy has developed rapidly. The previous research has focused on the preparation of tissue equivalent scintillator gels, luminosity measurements, light transmission and corrosion resistance of the phantom shell material and phantom preparation. The purpose of this work is to research the acquisition and processing of light field images. Firstly, an ultra-low noise & highly sensitive light field camera which spatial resolution can reach the sub-millimeter or even micron level was built by using a micro-lens array. And then the point spread functions (PSF) of the light field camera on different refocus positions were also studied by the knife edge method. Secondly, the 3D information of the object was reconstructed after the depth information recorded in the light field image was extracted. As exploration, reconstructing the 3D information of the inclined ruler was carried out, and the result which the length of the reconstructed inclined portion compared with the actual scale shows an error of about 5%. In addition, for the reconstruction of the internal scintillation light in the transparent scintillation gel, the optical layered imaging experiment using the candle flame as the research object was carried out, and the actual light intensity distributions of the candle flame at different levels are about to be obtained. The research in this paper will be continued, and the depth acquisition algorithm and the refocusing algorithm will be continuously optimized to obtain the better 3D reconstruction results.