Abstract: Volume rendering has numerous applications in medical visualization.However,its computational complexity is significantly higher than that ofsurface rendering,making it chauenging to achieve real-time rendering.A new empty space skipping method is proposed to accelerate the volume rendering process and reduce the space occupied during rendering.This method builds upon the state-of-the-art empty space skipping method(Chebyshev distance empty space skipping).It enhances the process of the ray casting algorithm,skips empty blocks using a low-resolution distance map and skips smaller empty blocks inside the effective block using a high-resolution distance map.The high-resolution distance map is stored exclusively within the effective block,effectively mitigating the increased memory overhead associated with introducing the high-resolution distance map.More-over,the space-saving effect is more pronounced in the context of sparser volume data.The performance metrics of the novel method is compared with Chebyshev distance empty space skipping,and the results indicate that the proposed method combines the advantages of Chebyshev distance map acceleration,resulting in significant improvements in rendering frame rate and space occupied during volume rendering with sparse data.

Key words: Real-time volume rendering, Ray casting, Empty space skipping, Chebyshev distance map, Sparse volume data