no code implementations • 24 Jan 2023 • Erik Wallin, Lennart Svensson, Fredrik Kahl, Lars Hammarstrand
In contrast, we propose an OSSL framework that facilitates learning from all unlabeled data through self-supervision.
no code implementations • 29 Sep 2022 • Georg Bökman, Axel Flinth, Fredrik Kahl
Equivariance of linear neural network layers is well studied.
1 code implementation • 11 May 2022 • Erik Wallin, Lennart Svensson, Fredrik Kahl, Lars Hammarstrand
Following the success of supervised learning, semi-supervised learning (SSL) is now becoming increasingly popular.
1 code implementation • 21 Apr 2022 • Georg Bökman, Fredrik Kahl
The aim of this paper is to demonstrate that a state of the art feature matcher (LoFTR) can be made more robust to rotations by simply replacing the backbone CNN with a steerable CNN which is equivariant to translations and image rotations.
no code implementations • 31 Jan 2022 • Lucas Brynte, Georg Bökman, Axel Flinth, Fredrik Kahl
We characterize the class of image plane transformations which realize rigid camera motions and call these transformations `rigidity preserving'.
1 code implementation • CVPR 2022 • Georg Bökman, Fredrik Kahl, Axel Flinth
In this paper, we are concerned with rotation equivariance on 2D point cloud data.
no code implementations • ICCV 2021 • Ara Jafarzadeh, Manuel Lopez Antequera, Pau Gargallo, Yubin Kuang, Carl Toft, Fredrik Kahl, Torsten Sattler
Visual localization is the problem of estimating the position and orientation from which a given image (or a sequence of images) is taken in a known scene.
no code implementations • CVPR 2021 • Carl Olsson, Viktor Larsson, Fredrik Kahl
In this paper we study structure from motion problems for 1D radial cameras.
1 code implementation • CVPR 2021 • Paul-Edouard Sarlin, Ajaykumar Unagar, Måns Larsson, Hugo Germain, Carl Toft, Viktor Larsson, Marc Pollefeys, Vincent Lepetit, Lars Hammarstrand, Fredrik Kahl, Torsten Sattler
In this paper, we go Back to the Feature: we argue that deep networks should focus on learning robust and invariant visual features, while the geometric estimation should be left to principled algorithms.
1 code implementation • CVPR 2021 • Kunal Chelani, Fredrik Kahl, Torsten Sattler
To address the resulting potential privacy risks for user-generated content, it was recently proposed to lift point clouds to line clouds by replacing 3D points by randomly oriented 3D lines passing through these points.
no code implementations • 6 Jan 2021 • Lucas Brynte, Viktor Larsson, José Pedro Iglesias, Carl Olsson, Fredrik Kahl
In studying the empirical performance we note that there are few failure cases reported in the literature, in particular for estimation problems with a single rotation, motivating us to gain further theoretical understanding.
no code implementations • 1 Jan 2021 • Carl Toft, Georg Bökman, Fredrik Kahl
In this work, we analyze linear operators from $L^2(S^2) \rightarrow L^2(S^2)$ which are equivariant to azimuthal rotations, that is, rotations around the z-axis.
1 code implementation • 21 Aug 2020 • Carl Toft, Daniyar Turmukhambetov, Torsten Sattler, Fredrik Kahl, Gabriel Brostow
Good local features improve the robustness of many 3D re-localization and multi-view reconstruction pipelines.
no code implementations • BMVC 2020 • Lucas Brynte, Fredrik Kahl
In recent years, considerable progress has been made for the task of rigid object pose estimation from a single RGB-image, but achieving robustness to partial occlusions remains a challenging problem.
Ranked #5 on
6D Pose Estimation using RGB
on Occlusion LineMOD
1 code implementation • 18 Aug 2019 • Måns Larsson, Erik Stenborg, Carl Toft, Lars Hammarstrand, Torsten Sattler, Fredrik Kahl
In this paper, we propose a new neural network, the Fine-Grained Segmentation Network (FGSN), that can be used to provide image segmentations with a larger number of labels and can be trained in a self-supervised fashion.
no code implementations • 19 Jun 2019 • Eskil Jörgensen, Christopher Zach, Fredrik Kahl
We show how modeling heteroscedastic uncertainty improves performance upon our baseline, and furthermore, how back-propagation can be done through the optimizer in order to train the pipeline end-to-end for additional accuracy.
1 code implementation • 16 Mar 2019 • Måns Larsson, Erik Stenborg, Lars Hammarstrand, Torsten Sattler, Mark Pollefeys, Fredrik Kahl
We show that adding the correspondences as extra supervision during training improves the segmentation performance of the convolutional neural network, making it more robust to seasonal changes and weather conditions.
no code implementations • ECCV 2018 • Carl Toft, Erik Stenborg, Lars Hammarstrand, Lucas Brynte, Marc Pollefeys, Torsten Sattler, Fredrik Kahl
Robust and accurate visual localization across large appearance variations due to changes in time of day, seasons, or changes of the environment is a challenging problem which is of importance to application areas such as navigation of autonomous robots.
2 code implementations • CVPR 2018 • Torsten Sattler, Will Maddern, Carl Toft, Akihiko Torii, Lars Hammarstrand, Erik Stenborg, Daniel Safari, Masatoshi Okutomi, Marc Pollefeys, Josef Sivic, Fredrik Kahl, Tomas Pajdla
Visual localization enables autonomous vehicles to navigate in their surroundings and augmented reality applications to link virtual to real worlds.
no code implementations • CVPR 2018 • Anders Eriksson, Carl Olsson, Fredrik Kahl, Tat-Jun Chin
In this paper we explore the role of duality principles within the problem of rotation averaging, a fundamental task in a wide range of computer vision applications.
no code implementations • 24 Jan 2017 • Måns Larsson, Anurag Arnab, Fredrik Kahl, Shuai Zheng, Philip Torr
It is empirically demonstrated that such learned potentials can improve segmentation accuracy and that certain label class interactions are indeed better modelled by a non-Gaussian potential.
no code implementations • CVPR 2016 • Behrooz Nasihatkon, Frida Fejne, Fredrik Kahl
In this paper, we propose a dual algorithm in which the optimization is done in the Fourier domain, and multiple resolution levels are replaced by multiple frequency bands.
no code implementations • CVPR 2016 • Erik Bylow, Carl Olsson, Fredrik Kahl, Mikael Nilsson
In the latter case, matrices are divided into sub-matrices and the envelope is computed for each sub-block individually.
no code implementations • CVPR 2016 • Johan Fredriksson, Viktor Larsson, Carl Olsson, Fredrik Kahl
Previous work on estimating the epipolar geometry of two views relies on being able to reliably match feature points based on appearance.
no code implementations • 14 Oct 2015 • Behrooz Nasihatkon, Fredrik Kahl
Our results show that low resolution target values can tightly bound the high-resolution target function in natural images.
no code implementations • CVPR 2014 • Yubin Kuang, Jan E. Solem, Fredrik Kahl, Kalle Astrom
In this paper, we study the problems of estimating relative pose between two cameras in the presence of radial distortion.
no code implementations • CVPR 2014 • Linus Svarm, Olof Enqvist, Magnus Oskarsson, Fredrik Kahl
For one, it makes the correspondence problem very difficult and it is likely that there will be a significant rate of outliers to handle.
no code implementations • CVPR 2014 • Johan Fredriksson, Olof Enqvist, Fredrik Kahl
It has long been recognized that one of the fundamental difficulties in theestimation of two-view epipolar geometry is the capability of handling outliers.
no code implementations • CVPR 2013 • Erik Ask, Olof Enqvist, Fredrik Kahl
First, it is shown that for a large class of problems, the statistically more desirable truncated L 2 -norm can be optimized with the same complexity.