​​On Neural Rendering What is Neural Rendering? In a nutshell | Gradient Dude

​​On Neural Rendering

What is Neural Rendering? In a nutshell, neural rendering is when we take classic algorithms for image rendering from computer graphics and replace a part of the pipeline with neural networks (stupid, but effective). Neural rendering learns to render and represent a scene from one or more input photos by simulating the physical process of a camera that captures the scene. A key property of 3D neural rendering is the disentanglement of the camera capturing process (i.e., the projection and image formation) and the representation of a 3D scene during training. That is, we learn an explicit (voxels, point clouds, parametric surfaces) or an implicit (signed distance function) representation of a 3D scene. For training, we use observations of the scene from several camera viewpoints. The network is trained on these observations by rendering the estimated 3D scene from the training viewpoints, and minimizing the difference between the rendered and observed images. This learned scene representation can be rendered from any virtual camera in order to synthesize novel views. It is important for learning that the entire rendering pipeline is differentiable.

You may have noticed, that the topic of neural rendering, including all sorts of nerfs-schmerfs, is now a big hype in computer vision. You might say that neural rendering is very slow, and you'd be right. A typical training session on a small scene with ~ 50 input photos takes about 5.5 hours for the fastest method on a single GPU, but neural rendering methods have made significant progress in the last year improving both fidelity and efficiency. To catch up on all the recent developments in this direction, I highly recommend reading this SOTA report "Advances in Neural Rendering".

The gif is from Volume Rendering of Neural Implicit Surfaces paper.