NoPose-NeuS: Jointly Optimizing Camera Poses with Neural Implicit Surfaces

Mohamed Shawky Sabae1, Hoda Anis Baraka1, Mayada Mansour Hadhoud1,2

1 Faculty of Engineering, Cairo University 2 University of Science and Technology Zewail City

NoPose-NeuS: NeurIPS 2023 UniReps Workshop

BA-NeuS: Springer Nature Virtual Reality Journal, 2026

Pipeline Overview

NoPose-NeuS Pipeline

NoPose-NeuS architecture diagram
NoPose-NeuS is the workshop pipeline: it optimizes camera poses together with the neural implicit geometry and appearance networks, forming the pose-estimation foundation that BA-NeuS extends.

BA-NeuS Pipeline

BA-NeuS architecture diagram
BA-NeuS is the journal extension of NoPose-NeuS: it keeps the joint neural surface optimization and adds camera-intrinsics estimation with a multi-view point-cloud alignment constraint.

Abstract

Neural implicit surface methods can recover challenging geometry, including thin structures and non-Lambertian surfaces, but they typically require accurate camera parameters. NoPose-NeuS relaxes this assumption by extending NeuS to optimize camera poses together with geometry and appearance.

NoPose-NeuS represents camera poses with an MLP and adds multi-view feature consistency plus rendered-depth supervision. These constraints help recover camera poses while preserving high-quality reconstructed surfaces.

BA-NeuS is the extended journal version of this work. It builds on NoPose-NeuS by jointly optimizing camera intrinsics in addition to poses, and by adding a multi-view point-cloud alignment constraint for more stable camera-parameter estimation.

Method Overview

Joint Optimization

Camera poses are optimized with the SDF geometry and color networks instead of being treated as fixed inputs.

Pose MLP

Each camera index is mapped through Gaussian Fourier features, then decoded by an MLP into rotation and translation parameters.

Geometry Constraints

Multi-view feature consistency and rendered depth loss guide the pose estimates and reduce degenerate surface solutions.

Object-Level Results

BA-NeuS extends NoPose-NeuS by estimating camera intrinsics together with camera poses. On DTU, the journal version gives a modest average Chamfer-distance improvement over NoPose-NeuS while remaining comparable to posed-reconstruction baselines such as NeuS and MonoSDF.

Method Camera Setting DTU Chamfer ↓ RPEr RPEt
COLMAP Estimates cameras 1.36 0.67 0.95
NeuS Uses accurate cameras 0.84 -- --
MonoSDF Uses accurate cameras 0.84 -- --
NoPose-NeuS Optimizes poses 0.89 0.63 0.93
BA-NeuS Optimizes poses and intrinsics 0.86 0.62 0.90
DTU mean results comparing NoPose-NeuS, which optimizes camera poses, with BA-NeuS, which extends it by optimizing poses and intrinsics. RPE values compare the methods that estimate camera parameters; lower is better.

DTU Reconstruction Comparisons

DTU Scan 24

DTU scan 24 reference RGB
Reference
DTU scan 24 BA-NeuS result
BA-NeuS
DTU scan 24 NoPose-NeuS result
NoPose-NeuS
DTU scan 24 NeuS result
NeuS
DTU scan 24 MonoSDF result
MonoSDF
DTU scan 24 COLMAP result
COLMAP

DTU Scan 37

DTU scan 37 reference RGB
Reference
DTU scan 37 BA-NeuS result
BA-NeuS
DTU scan 37 NoPose-NeuS result
NoPose-NeuS
DTU scan 37 NeuS result
NeuS
DTU scan 37 MonoSDF result
MonoSDF
DTU scan 37 COLMAP result
COLMAP

DTU Scan 55

DTU scan 55 reference RGB
Reference
DTU scan 55 BA-NeuS result
BA-NeuS
DTU scan 55 NoPose-NeuS result
NoPose-NeuS
DTU scan 55 NeuS result
NeuS
DTU scan 55 MonoSDF result
MonoSDF
DTU scan 55 COLMAP result
COLMAP

DTU Scan 65

DTU scan 65 reference RGB
Reference
DTU scan 65 BA-NeuS result
BA-NeuS
DTU scan 65 NoPose-NeuS result
NoPose-NeuS
DTU scan 65 NeuS result
NeuS
DTU scan 65 MonoSDF result
MonoSDF
DTU scan 65 COLMAP result
COLMAP

DTU Scan 63

DTU scan 63 reference RGB
Reference
DTU scan 63 BA-NeuS result
BA-NeuS
DTU scan 63 NoPose-NeuS result
NoPose-NeuS
DTU scan 63 NeuS result
NeuS
DTU scan 63 MonoSDF result
MonoSDF
DTU scan 63 COLMAP result
COLMAP

DTU Scan 106

DTU scan 106 reference RGB
Reference
DTU scan 106 BA-NeuS result
BA-NeuS
DTU scan 106 NoPose-NeuS result
NoPose-NeuS
DTU scan 106 NeuS result
NeuS
DTU scan 106 MonoSDF result
MonoSDF
DTU scan 106 COLMAP result
COLMAP

DTU Scan 118

DTU scan 118 reference RGB
Reference
DTU scan 118 BA-NeuS result
BA-NeuS
DTU scan 118 NoPose-NeuS result
NoPose-NeuS
DTU scan 118 NeuS result
NeuS
DTU scan 118 MonoSDF result
MonoSDF
DTU scan 118 COLMAP result
COLMAP
DTU surface reconstruction comparisons showing BA-NeuS against NoPose-NeuS and posed baselines. BA-NeuS extends NoPose-NeuS by estimating intrinsics in addition to poses, while NeuS and MonoSDF use accurate camera parameters.

BlendedMVS Reconstruction Comparisons

Bear

BlendedMVS bear reference RGB
Reference
BlendedMVS bear BA-NeuS result
BA-NeuS
BlendedMVS bear NoPose-NeuS result
NoPose-NeuS
BlendedMVS bear NeuS result
NeuS
BlendedMVS bear MonoSDF result
MonoSDF
BlendedMVS bear COLMAP result
COLMAP

Clock

BlendedMVS clock reference RGB
Reference
BlendedMVS clock BA-NeuS result
BA-NeuS
BlendedMVS clock NoPose-NeuS result
NoPose-NeuS
BlendedMVS clock NeuS result
NeuS
BlendedMVS clock MonoSDF result
MonoSDF
BlendedMVS clock COLMAP result
COLMAP

Dog

BlendedMVS dog reference RGB
Reference
BlendedMVS dog BA-NeuS result
BA-NeuS
BlendedMVS dog NoPose-NeuS result
NoPose-NeuS
BlendedMVS dog NeuS result
NeuS
BlendedMVS dog MonoSDF result
MonoSDF
BlendedMVS dog COLMAP result
COLMAP

Man

BlendedMVS man reference RGB
Reference
BlendedMVS man BA-NeuS result
BA-NeuS
BlendedMVS man NoPose-NeuS result
NoPose-NeuS
BlendedMVS man NeuS result
NeuS
BlendedMVS man MonoSDF result
MonoSDF
BlendedMVS man COLMAP result
COLMAP

Sculpture

BlendedMVS sculpture reference RGB
Reference
BlendedMVS sculpture BA-NeuS result
BA-NeuS
BlendedMVS sculpture NoPose-NeuS result
NoPose-NeuS
BlendedMVS sculpture NeuS result
NeuS
BlendedMVS sculpture MonoSDF result
MonoSDF
BlendedMVS sculpture COLMAP result
COLMAP

Stone

BlendedMVS stone reference RGB
Reference
BlendedMVS stone BA-NeuS result
BA-NeuS
BlendedMVS stone NoPose-NeuS result
NoPose-NeuS
BlendedMVS stone NeuS result
NeuS
BlendedMVS stone MonoSDF result
MonoSDF
BlendedMVS stone COLMAP result
COLMAP
BlendedMVS qualitative comparisons showing how BA-NeuS changes the pose-only NoPose-NeuS reconstruction setting by also estimating camera intrinsics. Ground-truth meshes are not available in this evaluation setup, so these results are shown qualitatively.

Scene-Level Results

The main practical difference between BA-NeuS and NoPose-NeuS appears in indoor ScanNet scenes. The point-cloud alignment term gives a more direct geometric signal for long image sequences, though the method can still be sensitive to limited overlap.

ScanNet Indoor Comparisons

ScanNet Scan 3

ScanNet scan 3 BA-NeuS result
BA-NeuS
Chamfer 0.287
ScanNet scan 3 MonoSDF result
MonoSDF
Chamfer 0.215
ScanNet scan 3 NoPose-NeuS result
NoPose-NeuS
Chamfer 0.411

ScanNet Scan 1

ScanNet scan 1 BA-NeuS result
BA-NeuS
Chamfer 0.377
ScanNet scan 1 MonoSDF result
MonoSDF
Chamfer 0.195
ScanNet scan 1 NoPose-NeuS result
NoPose-NeuS
Chamfer 0.591
ScanNet indoor scene results comparing BA-NeuS with NoPose-NeuS. Both estimate camera parameters, while MonoSDF uses accurate camera parameters; the comparison highlights the indoor-scene effect of the BA-NeuS point-cloud alignment extension.

BibTeX

NoPose-NeuS

@inproceedings{
sabae2023noposeneus,
title={NoPose-NeuS: Jointly Optimizing Camera Poses with Neural Implicit Surfaces for Multi-view Reconstruction},
author={Mohamed Shawky Sabae and Hoda A. Baraka and Mayada Hadhoud},
booktitle={UniReps:  the First Workshop on Unifying Representations in Neural Models},
year={2023},
url={https://openreview.net/forum?id=TOp8uT3DZ9}
}

BA-NeuS

@Article{sabae2026baneus,
author={Sabae, Mohamed Shawky
and Baraka, Hoda Anis
and Hadhoud, Mayada Mansour},
title={Ba-neus: joint optimization of neural implicit camera and geometry representations for multiview 3D reconstruction},
journal={Virtual Reality},
year={2026},
month={Jul},
day={01},
volume={30},
number={3},
pages={131},
abstract={3D reconstruction from multi-view RGB images is important for computer vision and computer graphics applications. Recently, neural surface reconstruction methods have shown promising results for reconstructing detailed 3D geometry in complex scenes. These methods can complement classical multi-view stereo approaches, especially under challenging appearance conditions such as non-Lambertian surfaces and thin structures. A common assumption for these methods is the availability of accurate multi-view camera parameters, which limits their applicability to real-world problems. In this paper, we present bundle-adjusting NeuS (BA-NeuS), a neural surface reconstruction method that integrates the core principle of BA, the joint and simultaneous optimization of 3D structure and camera parameters, directly into the neural reconstruction pipeline. Building on NoPose-NeuS and NeuS, our method performs this BA by jointly optimizing: (1) the implicit neural surface representation (the structure) and (2) the multi-view camera parameters (the motion). To achieve this, we represent the camera parameters, including not only poses but also intrinsics (focal length and optical center), as a multi-layer perceptron. We propose an additional multi-view point cloud alignment loss function that constrains this joint optimization and stabilizes camera-parameter estimation. Our experiments on object-level and scene-level datasets show that the proposed method can reconstruct plausible scene surfaces while estimating camera parameters in the evaluated settings. Compared with baselines that also estimate camera parameters, BA-NeuS gives a modest average improvement on DTU, achieving a mean Chamfer distance of 0.86 compared with 0.89 for NoPose-NeuS, while additionally optimizing camera intrinsics. The code is available at: https://github.com/DarkGeekMS/bundle-adjusting-neus.},
issn={1434-9957},
doi={10.1007/s10055-026-01423-1},
url={https://doi.org/10.1007/s10055-026-01423-1}
}