4D volume rendering by differential splatting

X-ray like volume rendering is adapted to time-varying data visualization. The proposed method can be interpreted as an object-order version of differential volume rendering. Time steps are encoded as a sequence of differential volumes which are then directly projected onto the image plane to calculate differential images between consecutive frames. The projection of differential volumes is performed by using the splatting method. Due to the simplified visualization model and the object-order approach, those pixels which are affected by the changed voxels can be directly refreshed, without resampling the volume by ray casting. However, compositing is limited to intensity integration. In order to improve spatial impression, differential splatting is extended to depth cueing and hemispherical shading.