NeRF represents a scene with learned, continuous volumetric radiance field $F_\theta$ defined over a bounded 3D volume. In a NeRF, $F_\theta$ is a multilayer perceptron (MLP) that takes as input a 3D position $x = (x, y, z)$ and unit-norm viewing direction $d = (dx, dy, dz)$, and produces as output a density $\sigma$ and color $c = (r, g, b)$. The weights of the multilayer perceptron that parameterize $F_\theta$ are optimized so as to encode the radiance field of the scene. Volume rendering is used to compute the color of a single pixel.

The **MelGAN Residual Block** is a convolutional [residual block](https://paperswithcode.com/method/residual-block) used in the [MelGAN](https://paperswithcode.com/method/melgan) generative audio architecture. It employs residual connections with dilated convolutions. Dilations are used so that temporally far output activations of each subsequent layer has significant overlapping inputs. Receptive field of a stack of [dilated convolution](https://paperswithcode.com/method/dilated-convolution) layers increases exponentially with the number of layers. Incorporating these into the MelGAN generator allows us to efficiently increase the induced receptive fields of each output time-step. This effectively implies larger overlap in the induced receptive field of far apart time-steps, leading to better long range correlation.

MelGAN Residual Block

MelGAN: Generative Adversarial Networks for Conditional Waveform Synthesis

NeRF

NeRF: Representing Scenes as Neural Radiance Fields for View Synthesis

**Hierarchical Feature Fusion (HFF)** is a feature fusion method employed in [ESP](https://paperswithcode.com/method/esp) and [EESP](https://paperswithcode.com/method/eesp) image model blocks for degridding. In the ESP module, concatenating the outputs of dilated convolutions gives the ESP module a large effective receptive field, but it introduces unwanted checkerboard or gridding artifacts. To address the gridding artifact in ESP, the feature maps obtained using kernels of different dilation rates are hierarchically added before concatenating them (HFF). This solution is simple and effective and does not increase the complexity of the ESP module.

Source	NeRF: Representing Scenes as Neural Radiance Fields for View Synthesis
Year	2000
Data Source	CC BY-SA - https://paperswithcode.com