Geometric Algebra Planes: Convex Implicit Neural Volumes

Fuente: arXiv
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Main Authors: Sivgin, Irmak, Fridovich-Keil, Sara, Wetzstein, Gordon, Pilanci, Mert
Format: Preprint
Published: 2024
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author Sivgin, Irmak
Fridovich-Keil, Sara
Wetzstein, Gordon
Pilanci, Mert
author_facet Sivgin, Irmak
Fridovich-Keil, Sara
Wetzstein, Gordon
Pilanci, Mert
contents Volume parameterizations abound in recent literature, from the classic voxel grid to the implicit neural representation and everything in between. While implicit representations have shown impressive capacity and better memory efficiency compared to voxel grids, to date they require training via nonconvex optimization. This nonconvex training process can be slow to converge and sensitive to initialization and hyperparameter choices that affect the final converged result. We introduce a family of models, GA-Planes, that is the first class of implicit neural volume representations that can be trained by convex optimization. GA-Planes models include any combination of features stored in tensor basis elements, followed by a neural feature decoder. They generalize many existing representations and can be adapted for convex, semiconvex, or nonconvex training as needed for different inverse problems. In the 2D setting, we prove that GA-Planes is equivalent to a low-rank plus low-resolution matrix factorization; we show that this approximation outperforms the classic low-rank plus sparse decomposition for fitting a natural image. In 3D, we demonstrate GA-Planes' competitive performance in terms of expressiveness, model size, and optimizability across three volume fitting tasks: radiance field reconstruction, 3D segmentation, and video segmentation.
format Preprint
id arxiv_https___arxiv_org_abs_2411_13525
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Geometric Algebra Planes: Convex Implicit Neural Volumes
Sivgin, Irmak
Fridovich-Keil, Sara
Wetzstein, Gordon
Pilanci, Mert
Computer Vision and Pattern Recognition
Volume parameterizations abound in recent literature, from the classic voxel grid to the implicit neural representation and everything in between. While implicit representations have shown impressive capacity and better memory efficiency compared to voxel grids, to date they require training via nonconvex optimization. This nonconvex training process can be slow to converge and sensitive to initialization and hyperparameter choices that affect the final converged result. We introduce a family of models, GA-Planes, that is the first class of implicit neural volume representations that can be trained by convex optimization. GA-Planes models include any combination of features stored in tensor basis elements, followed by a neural feature decoder. They generalize many existing representations and can be adapted for convex, semiconvex, or nonconvex training as needed for different inverse problems. In the 2D setting, we prove that GA-Planes is equivalent to a low-rank plus low-resolution matrix factorization; we show that this approximation outperforms the classic low-rank plus sparse decomposition for fitting a natural image. In 3D, we demonstrate GA-Planes' competitive performance in terms of expressiveness, model size, and optimizability across three volume fitting tasks: radiance field reconstruction, 3D segmentation, and video segmentation.
title Geometric Algebra Planes: Convex Implicit Neural Volumes
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2411.13525