DRR volume rendering using splatting in shear-warp context

Digital Reconstruction Radiography (DRR) is an important technique in radiotherapy imaging applications. DRR volume rendering aims at rendering DRR images using CT or other tomographic data sets. In addition to the appropriate optical model, the interactive and realistic DRR imaging depends mainly on an accurate attenuation coefficient transfer function, which is usually a piecewise function, and an interactive rendering algorithm with reasonable rendering quality. In this paper, we first present a realistic DRR transfer function based on the mass attenuation coefficient composition. Then, we introduce an object space DRR rendering algorithm, DRR splatting in the sheared object space. The DRR image qualities under different rendering algorithms are compared, including ray casting, Fourier volume rendering, projective shear-warp and splatting shear-warp. Finally, a line encoding technique is adopted to accelerate DRR rendering