Real-time Appearance-Driven Memory-Efficient Dense Foliage Synthesis

   Precisely reconstructed landscape models can bridge gaps between design and construction while also providing realistic design visualizations and demonstrations. Though trees are indispensable among the landscapes, they generally function as visual references in interactive design and it is not worthwhile to consume too many resources for highly detailed representation and reconstruction. However, the state-of-the-art mainly focuses on replicating lifelike geometric and topological details with unconstrained memory usage and rendering cost, and a scenario to reconstruct canopies with low resource usage has yet to be well investigated in related domains. Therefore, this work seeks a method to synthesize highly realistic dense tree canopies with minimal memory consumption and superior rendering efficiency. In order to save memory usage from traditional procedural and aerial reconstruction, we first optimally place the semi-ellipsoids, denoted as proxy, to preserve the shape and contour by fitting the silhouette under different views. Then, exemplar leaves, denoted as instance, are quasi-randomly distributed on the proxy shell for the aggregated appearance of leaf clusters and further memory preservation. We further compress the view-dependent high-varied visual appearance, generally recorded as multiple high resolution textures, as the composition of view-independent diffuse coloring and view-dependent residual lighting. The former compresses coloring textures as the quantized representative color of each instance, and the latter encodes pixel-based multi-view subtlety textures as lobe-based light fields. Finally, we have conducted several experiments and a user study to compare our method against two state-of-the-art baselines, branch-based procedural modeling and surface-based aerial reconstruction, in the aspect of visual appearance and memory usage. Accordingly, ours can provide the best visual reference with much lower memory usage, i.e., a higher compression rate.