Learning to Predict 3D Objects with an Interpolation-based Differentiable Renderer

Chen, Wenzheng, Ling, Huan, Gao, Jun, Smith, Edward, Lehtinen, Jaakko, Jacobson, Alec, Fidler, Sanja

Neural Information Processing Systems 

Many machine learning models operate on images, but ignore the fact that images are 2D projections formed by 3D geometry interacting with light, in a process called rendering. Enabling ML models to understand image formation might be key for generalization. However, due to an essential rasterization step involving discrete assignment operations, rendering pipelines are non-differentiable and thus largely inaccessible to gradient-based ML techniques. In this paper, we present DIB-Render, a novel rendering framework through which gradients can be analytically computed. Key to our approach is to view rasterization as a weighted interpolation, allowing image gradients to back-propagate through various standard vertex shaders within a single framework.