Neural Implicit Dictionary via Mixture-of-Expert Training

TL;DR

This paper introduces a Neural Implicit Dictionary framework that leverages a mixture-of-experts approach to efficiently represent and reconstruct complex visual signals, significantly reducing training time and data requirements.

Contribution

It proposes a novel Neural Implicit Dictionary that enables instant scene representation by learning a basis set from data, using a sparse gating mixture-of-experts model for efficient training.

Findings

Achieves 100x faster reconstruction than traditional INRs.

Reduces input data needs by up to 98%.

Effective in image inpainting and occlusion removal.

Abstract

Representing visual signals by coordinate-based deep fully-connected networks has been shown advantageous in fitting complex details and solving inverse problems than discrete grid-based representation. However, acquiring such a continuous Implicit Neural Representation (INR) requires tedious per-scene training on tons of signal measurements, which limits its practicality. In this paper, we present a generic INR framework that achieves both data and training efficiency by learning a Neural Implicit Dictionary (NID) from a data collection and representing INR as a functional combination of basis sampled from the dictionary. Our NID assembles a group of coordinate-based subnetworks which are tuned to span the desired function space. After training, one can instantly and robustly acquire an unseen scene representation by solving the coding coefficients. To parallelly optimize a large group of networks, we borrow the idea from Mixture-of-Expert (MoE) to design and train our network with a sparse gating mechanism. Our experiments show that, NID can improve reconstruction of 2D images or 3D scenes by 2 orders of magnitude faster with up to 98% less input data. We further demonstrate various applications of NID in image inpainting and occlusion removal, which are considered to be challenging with vanilla INR. Our codes are available in https://github.com/VITA-Group/Neural-Implicit-Dict.