Blind Augmentation: Calibration-free Camera Distortion Model Estimation for Real-time Mixed-reality Consistency

IEEE Transactions on Visualization and Computer Graphics (IEEEVR 2025)

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Teaser

Our method “blindly” estimates a model of noise, motion blur (MB) and depth of field (DoF) from input frames (left), i.e., without requiring any known calibration markers / objects. The model can then augment other images with virtual objects that appear visually consistent (middle).

Abstract

Real camera footage is subject to noise, motion blur (MB) and depth of field (DoF). In some applications these might be considered distortions to be removed, but in others it is important to model them because it would be ineffective, or interfere with an aesthetic choice, to simply remove them. In augmented reality applications where virtual content is composed into a live video feed, we can model noise, MB and DoF to make the virtual content visually consistent with the video. Existing methods for this typically suffer two main limitations. First, they require a camera calibration step to relate a known calibration target to the specific cameras response. Second, existing work require methods that can be (differentiably) tuned to the calibration, such as slow and specialized neural networks. We propose a method which estimates parameters for noise, MB and DoF instantly, which allows using off-the-shelf real-time simulation methods from e.g., a game engine in compositing augmented content. Our main idea is to unlock both features by showing how to use modern computer vision methods that can remove noise, MB and DoF from the video stream, essentially providing self-calibration. This allows to auto-tune any black-box real-time noise+MB+DoF method to deliver fast and high-fidelity augmentation consistency.

Supplementary Video

Overview

Overview

Overview of our approach, comprising of a training part (top half) and a test or deployment phase (bottom half). Training starts with the input image I at the top left that is fed into off-the-shelf depth and flow extractors, as well as off-the-shelf methods to remove noise, MB and DoF. These off-the-shelf processes are denoted as (black arrows). Next, the image difference between a re-synthesis of noise, MB and DoF is computed and compared to the input image (orange arrows). This error is minimized by back-propagating to the noise, MB and DoF parameters (blue arrows}). This forms a model that knows the noise profile, how to blur for which depth or which motion (top right). At test time, we know flow and depth of a virtual RGB image, and hence can synthesize noise, MB and DoF (pink arrows) using off-the-shelf and fast methods, before composing a final image with consistency superior to no noise, MB and DoF.

Results


Consistent (Ours) vs Naive Compositing

Consistent Compositing (Ours) vs Naive Compositing
Example 1 After
Naive Compositing
Example 1 Before
Consistent Compositing (Ours)
Consistent Compositing (Ours) vs Naive Compositing
Example 2 After
Naive Compositing
Example 2 Before
Consistent Compositing (Ours)
Consistent Compositing (Ours) vs Naive Compositing
Example 1 After
Naive Compositing
Example 1 Before
Consistent Compositing (Ours)
Consistent Compositing (Ours) vs Naive Compositing
Example 2 After
Naive Compositing
Example 2 Before
Consistent Compositing (Ours)
Consistent Compositing (Ours) vs Naive Compositing
Example 1 After
Naive Compositing
Example 1 Before
Consistent Compositing (Ours)
Consistent Compositing (Ours) vs Naive Compositing
Example 2 After
Naive Compositing
Example 2 Before
Consistent Compositing (Ours)
Consistent Compositing (Ours) vs Naive Compositing
Example 1 After
Naive Compositing
Example 1 Before
Consistent Compositing (Ours)
Consistent Compositing (Ours) vs Naive Compositing
Example 2 After
Naive Compositing
Example 2 Before
Consistent Compositing (Ours)

Real-time Optimization Update

We can run optimization over multiple frames to update the distortion parameters in real-time.

The effect can be seen on composited objects with changing distortions over time which is consistent with real objects.

Varying Focus
Varying ISO (Noise)

BibTeX

@ARTICLE{10919204,
  author={Prakash, Siddhant and Walton, David R. and Anjos, Rafael K. dos and Steed, Anthony and Ritschel, Tobias},
  journal={IEEE Transactions on Visualization and Computer Graphics},
  title={Blind Augmentation: Calibration-free Camera Distortion Model Estimation for Real-time Mixed-reality Consistency},
  year={2025},
  volume={},
  number={},
  pages={1-11},
  keywords={Noise;Cameras;Distortion;Streaming media;Calibration;Training;Real-time systems;Rendering (computer graphics);Geometry;Image color analysis;Augmented Reality;optimization},
  doi={10.1109/TVCG.2025.3549541}}

}
 

Acknowledgments and Funding

The authors wish to thank Sebastian Friston and David Swapp for early discussions, and David Mandl for providing the code for Neural Cameras [MandlEtAl 2021]. This work was funded by the EPSRC/UKRI project EP/T01346X/1.