Fully self-supervised novel view synthesis

IRISImplicit Rendering Matters for
Pose-Free Novel View Synthesis

Wenyu LiSidun LiuPeng Qiao*Yong Dou*Tongrui Hu

National University of Defense Technology · Changsha, China

† Equal contribution    * Corresponding authors

Learning to see new views, without camera annotations.

Unordered reference images, synthesized views compared with E-RayZer, MVSplat and LVSM, and camera poses predicted by IRIS.
From unordered images to sharper novel views and geometrically grounded cameras.
Pose-free No camera annotationsField-based A latent neural representationSelf-supervised Learning directly from images

01 / Overview

A middle ground for
pose-free rendering.

Implicit modeling, with geometry built into the rendering process.

Novel view synthesis from unposed multi-view images requires learning scene representations and camera parameters together. Free latent-space rendering is flexible, but can yield weakly grounded cameras. Explicit 3D representations provide stronger geometric grounding, but introduce heavier parameterization and more fragile optimization.

IRIS represents the scene as a latent neural field. It queries that field under self-predicted cameras: features from reference images are projected onto sampled 3D points, aggregated across views, and then composed along target rays. This preserves the flexibility of implicit modeling while introducing geometric structure into rendering.

Read the full abstract

Novel view synthesis from unposed multi-view images remains challenging, as the model must jointly learn scene representations and camera parameters without pose supervision. Existing approaches largely fall into two extremes: implicit latent-space rendering is flexible and easy to optimize, but often yields weakly grounded camera estimation; explicit 3D representations provide stronger geometric grounding, but introduce heavier parameterization and more fragile optimization. In this paper, we present IRIS, a fully self-supervised framework that provides a practical middle ground between these two paradigms. Instead of decoding free latent tokens or reconstructing fully explicit 3D primitives, IRIS represents the scene as a latent neural field and renders novel views by querying this field under self-predicted cameras. Specifically, projected features from reference views are aggregated at sampled 3D points to form point-wise latent features, which are then composed along target rays for rendering. This design preserves the flexibility and optimization stability of implicit modeling, while introducing stronger geometric structure than unconstrained latent rendering. Extensive experiments show that IRIS achieves strong novel view synthesis quality with competitive pose accuracy under fully self-supervised learning.

02 / Video

See IRIS in motion.

Novel views. Predicted cameras.
A closer look at the results.

IRIS project demonstration 01:48 Download original video ↗

03 / Method

Images → field → novel views.

A shared encoder. Self-predicted cameras.
Geometry-aware implicit rendering.

IRIS architecture: a shared multi-view encoder extracts features and camera parameters, then queries a neural field along a target camera ray.
IRIS jointly learns camera estimation and scene representation through image-based supervision.
01

Encode & estimate

A shared multi-view encoder extracts reference features and predicts camera parameters from unposed images.

02

Query the field

At each sampled 3D point, projected reference features are aggregated across views into a point-wise latent feature.

03

Render along rays

A ray transformer composes the sampled point features to predict target colors, trained without pose annotations.

04 / Results

Sharper views.
Competitive camera estimation.

Evaluated on indoor and outdoor scenes,
including unseen datasets.

Re10K · PSNR31.272 dB

With image-only training supervision

DL3DV · unordered inputs+4.200 dB

PSNR over E-RayZer, DL3DV-only training

NRGBD · cross-dataset31.404 dB

PSNR with DL3DV-only training

Five scenes comparing predicted camera trajectories and rendered images from RayZer, E-RayZer and IRIS against ground truth.
Qualitative camera and rendering comparisons from the paper. Colored frustums show predicted trajectories; black frustums show the COLMAP reference.

Quantitative comparison

Single-source training on DL3DV · Paper, Table 3

Novel view synthesis and relative pose accuracy; higher is better except LPIPS.
Evaluation datasetMethodPSNR ↑SSIM ↑LPIPS ↓RPA @15° ↑
DL3DV Random orderE-RayZer21.1240.7010.2710.811
IRIS (ours)25.3240.7910.2150.863
NRGBDE-RayZer26.4760.8600.1440.800
IRIS (ours)31.4040.9210.1280.861
ScanNet++E-RayZer21.9920.7440.2590.252
IRIS (ours)22.9380.7630.2760.333
7ScenesE-RayZer26.7270.8700.1750.729
IRIS (ours)30.7830.9070.1400.749

Each test sample contains 16 reference views and 8 target views. Re10K results above use Re10K-only training (Table 5); the comparison table uses DL3DV-only training. IRIS trades additional rendering cost for synthesis quality; see the paper for full pose metrics, mixed-source results, and inference latency.

05 / Citation

BibTeX

If you find this work useful, please consider citing it.

@misc{li2026iris,
  title = {IRIS: Implicit Rendering Matters for Pose-Free
           Novel View Synthesis},
  author = {Li, Wenyu and Liu, Sidun and Qiao, Peng
            and Dou, Yong and Hu, Tongrui},
  year = {2026},
  url = {https://leo-frank.github.io/IRIS/}
}