Ronald Clark

dblp:138/3006 · DBLP profile ↗
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32ranked-venue papers
5as first author
14since 2021 · last 2025
0000-0002-6344-5299ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 26 · 4 first-author · 12 since 2021Graphics, computer vision, multimedia, augmented reality and games · 18 · 4 first-author · 6 since 2021Systems, architecture and hardware · 5 · 2 since 2021Computer networks · 2 · 1 first-author
YearPublicationVenuePosition
2025 Olympus: A Universal Task Router for Computer Vision Tasks
abstract
We introduce Olympus, a new approach that transforms Multimodal Large Language Models (MLLMs) into a unified framework capable of handling a wide array of computer vision tasks. Utilizing a controller MLLM, Olympus delegates over 20 specialized tasks across images, videos, and 3D objects to dedicated modules. This instruction-based routing enables complex workflows through chained actions without the need for training heavy generative models. Olympus easily integrates with existing MLLMs, expanding their capabilities with comparable performance. Experimental results demonstrate that Olympus achieves an average routing accuracy of 94.75% across 20 tasks and precision of 91.82% in chained action scenarios, showcasing its effectiveness as a universal task router that can solve a diverse range of computer vision tasks.
Yuanze Lin, Yunsheng Li, Dongdong Chen 0001, Weijian Xu, Ronald Clark, Philip Torr 0001
CVPR5
2025 Image as an Imu: Estimating Camera Motion From a Single Motion-Blurred Image
abstract
In many robotics and VR/AR applications, fast camera motions lead to a high level of motion blur, causing existing camera pose estimation methods to fail. In this work, we propose a novel framework that leverages motion blur as a rich cue for motion estimation rather than treating it as an unwanted artifact. Our approach works by predicting a dense motion flow field and a monocular depth map directly from a single motion-blurred image. We then recover the instantaneous camera velocity by solving a linear least squares problem under the small motion assumption. In essence, our method produces an IMU-like measurement that robustly captures fast and aggressive camera movements. To train our model, we construct a large-scale dataset with realistic synthetic motion blur derived from ScanNet++v2 and further refine our model by training end-to-end on real data using our fully differentiable pipeline. Extensive evaluations on real-world benchmarks demonstrate that our method achieves state-of-the-art angular and translational velocity estimates, outperforming current methods like MASt3R and COLMAP.
Jerred Chen, Ronald Clark
ICCV2
2025 Measuring what Matters: Construct Validity in Large Language Model Benchmarks
abstract
Evaluating large language models (LLMs) is crucial for both assessing their capabilities and identifying safety or robustness issues prior to deployment. Reliably measuring abstract and complex phenomena such as safety' androbustness' requires strong construct validity, that is, having measures that represent what matters to the phenomenon. With a team of 29 expert reviewers, we conduct a systematic review of 445 LLM benchmarks from leading conferences in natural language processing and machine learning. Across the reviewed articles, we find patterns related to the measured phenomena, tasks, and scoring metrics which undermine the validity of the resulting claims. To address these shortcomings, we provide eight key recommendations and detailed actionable guidance to researchers and practitioners in developing LLM benchmarks.
Andrew M. Bean 0001, Ryan Othniel Kearns, Angelika Romanou, Franziska Sofia Hafner, Harry Mayne, Jan Batzner, Negar Foroutan Eghlidi, Chris Schmitz, Karolina Korgul, Hunar Batra, Oishi Deb, Emma Beharry, Cornelius Emde, Thomas Foster, Anna Gausen, María Grandury, Simeng Han, Valentin Hofmann, Lujain Ibrahim, Hazel Kim, Hannah Kirk, Fangru Lin, Gabrielle K. Liu, Lennart Luettgau, Jabez Magomere, Jonathan Rystrøm, Anna Sotnikova, Yilun Zhao 0001, Adel Bibi, Antoine Bosselut, Ronald Clark, Arman Cohan, Jakob N. Foerster, Yarin Gal, Scott A. Hale, Inioluwa Deborah Raji, Christopher Summerfield, Philip Torr 0001, Cozmin Ududec, Luc Rocher, Adam Mahdi
NeurIPS32
2025 IllumiCraft: Unified Geometry and Illumination Diffusion for Controllable Video Generation
abstract
Although diffusion-based models can generate high-quality and high-resolution video sequences from textual or image inputs, they lack explicit integration of geometric cues when controlling scene lighting and visual appearance across frames. To address this limitation, we propose IllumiCraft, an end-to-end diffusion framework accepting three complementary inputs: (1) high-dynamic-range (HDR) video maps for detailed lighting control; (2) synthetically relit frames with randomized illumination changes (optionally paired with a static background reference image) to provide appearance cues; and (3) 3D point tracks that capture precise 3D geometry information. By integrating the lighting, appearance, and geometry cues within a unified diffusion architecture, IllumiCraft generates temporally coherent videos aligned with user-defined prompts. It supports the background-conditioned and text-conditioned video relighting and provides better fidelity than existing controllable video generation methods.
Yuanze Lin, Yi-Wen Chen, Yi-Hsuan Tsai, Ronald Clark, Ming-Hsuan Yang 0001
NeurIPS4
2025 Cloud4D: Estimating Cloud Properties at a High Spatial and Temporal Resolution
abstract
There has been great progress in improving numerical weather prediction and climate models using machine learning. However, most global models act at a kilometer-scale, making it challenging to model individual clouds and factors such as extreme precipitation, wind gusts, turbulence, and surface irradiance. Therefore, there is a need to move towards higher-resolution models, which in turn require high-resolution real-world observations that current instruments struggle to obtain. We present Cloud4D, the first learning-based framework that reconstructs a physically consistent, four–dimensional cloud state using only synchronized ground‐based cameras. Leveraging a homography-guided 2D‐to‐3D transformer, Cloud4D infers the full 3D distribution of liquid water content at 25 m spatial and 5 s temporal resolution. By tracking the 3D liquid water content retrievals over time, Cloud4D additionally estimates horizontal wind vectors. Across a two-month deployment comprising six skyward cameras, our system delivers an order-of-magnitude improvement in space-time resolution relative to state-of-the-art satellite measurements, while retaining single-digit relative error ($<10\\%$) against collocated radar measurements.
Jacob Lin, Edward Gryspeerdt, Ronald Clark
NeurIPS3
2024 Instant Uncertainty Calibration of NeRFs Using a Meta-calibrator
Niki Amini-Naieni, Tomas Jakab, Andrea Vedaldi, Ronald Clark
ECCV (78)4
2023 Learning Tethered Perching for Aerial Robots
abstract
Aerial robots have a wide range of applications, such as collecting data in hard-to-reach areas. This requires the longest possible operation time. However, because currently available commercial batteries have limited specific energy of roughly 300 W h kg-1, a drone's flight time is a bottleneck for sustainable long-term data collection. Inspired by birds in nature, a possible approach to tackle this challenge is to perch drones on trees, and environmental or man-made structures, to save energy whilst in operation. In this paper, we propose an algorithm to automatically generate trajectories for a drone to perch on a tree branch, using the proposed tethered perching mechanism with a pendulum-like structure. This enables a drone to perform an energy-optimised, controlled 180° flip to safely disarm upside down. To fine-tune a set of reachable trajectories, a soft actor critic-based reinforcement algorithm is used. Our experimental results show the feasibility of the set of trajectories with successful perching. Our findings demonstrate that the proposed approach enables energy-efficient landing for long-term data collection tasks.
Fabian Hauf, Basaran Bahadir Kocer, Alan Slatter, Hai-Nguyen Nguyen, Oscar Pang, Ronald Clark, Edward Johns, Mirko Kovac
ICRA6
2022 Volumetric Bundle Adjustment for Online Photorealistic Scene Capture
abstract
Efficient photorealistic scene capture is a challenging task. Current online reconstruction systems can operate very efficiently, but images generated from the models captured by these systems are often not photorealistic. Recent approaches based on neural volume rendering can render novel views at high fidelity, but they often require a long time to train, making them impractical for applications that require real-time scene capture. In this paper, we propose a system that can reconstruct photorealistic models of complex scenes in an efficient manner. Our system processes images online, i.e. it can obtain a good quality estimate of both the scene geometry and appearance at roughly the same rate the video is captured. To achieve the efficiency, we propose a hierarchical feature volume using VDB grids. This representation is memory efficient and allows for fast querying of the scene information. Secondly, we introduce a novel optimization technique that improves the efficiency of the bundle adjustment which allows our system to converge to the target camera poses and scene geometry much faster. Experiments on real-world scenes show that our method outperforms existing systems in terms of efficiency and capture quality. To the best of our knowledge, this is the first method that can achieve online photorealistic scene capture.
Ronald Clark
CVPR1
2022 Uncertainty Estimation with a VAE-Classifier Hybrid Model
abstract
We propose a hybrid model that combines a generative unit and a discriminative classifier to quantify uncertainty in a classification task. The representation learning capability in the VAE module allows our method to learn more useful and generalizable features and outperform other purely discriminative classifiers when training labels are limited. With proper statistical treatment, the probabilistic encoder in our VAE module offers a convenient mechanism to express uncertainty for out-of-distribution (OOD) data. As a result, our method gives better calibrated uncertainty prediction. We demonstrate the effectiveness of our method on MNIST and a challenging medical image dataset for skin lesion diagnosis.
Shuyu Lin, Ronald Clark, Agathoniki Trigoni, Stephen J. Roberts
ICASSP2
2022 Deep learning for 3D vision
abstract
With the rapid development of 3D imaging sensors, such as depth cameras and laser scanning systems, 3D data has become increasingly accessible. Meanwhile, the boost of various deep learning algorithms, such as convolutional neural networks and transformers, further increases the usability of 3D vision systems. Driven by these factors, 3D vision has become an emerging and core component for numerous applications, such as autonomous driving, augmented reality, virtual reality and robotics. Although remarkable progress has been achieved in this area during the last few years, there are still several challenges that need to be addressed, such as the noisy, sparse, and irregular nature of point clouds, the high cost to label 3D data and the necessity to integrate geometry-based and learning-based techniques. Besides, 3D data produced by different 3D imaging sensors (e.g. structured light, stereo, LiDAR and time-of-flight) can be highly different. It is, therefore, necessary to investigate general algorithms that can mitigate the domain gap between different types of 3D data. This special issue aims to collect and present the latest research development in learning-based 3D vision theories and their applications and to inspire future research in this area. In total, there are eight papers accepted for publication in this special issue through careful peer reviews and revisions. These accepted papers are broadly categorised into three topics, and the summary of each topic is given below. TOPIC A—OPTICAL FLOW AND DEPTH ESTIMATION Han et al., in their paper ‘DEMVSNet: Denoising and Depth Inference for Unstructured Multi-View Stereo on Noised Images’, proposed a DEMVSNet to simultaneously address the depth estimation and image denoising problems for unstructured multi-view stereo. The multi-scales feature maps for each image are wrapped to construct cost volumes containing both the depth and RGB information through differentiable homography and Gaussian probability mapping. The cost volume regularisation module is then adopted to predict the probability of depth and RGB. To avoid overfitting in multi-task learning, the gradient normalisation algorithm is utilised to dynamically fine-tune the weights between the depth prediction task and the denoising task. To evaluate the performance of proposed DEMVSNet, a noisy Technical University of Denmark dataset is generated by adding Gaussian-Poisson noise to each image, and the experimental results demonstrate the superiority of DEMVSNet on both the denoising and multi-view stereo reconstruction tasks. Lin et al., in their paper ‘EAGAN: Event-Based Attention Generative Adversarial Networks for Optical Flow and Depth Estimation’, proposed an event-based attention generative adversarial network named EAGAN to simultaneously deal with optical flow and depth estimation based on monocular event camera. The generator of EAGAN is similar to U-net except that a transformer structure is introduced between the encoder and decoder. The position-coding features learnt from the transformer is added to features learnt from the encoding layer, which helps to capture the correlation between sequence information. The discriminator of EAGAN is based on a fully convolutional network and aims to distinguish whether the depth image or the optical flow image is generated by the generator. Experimental results conducted on the multi-vehicle stereo event camera dataset demonstrate the effectiveness of EAGAN on both the depth and optical flow estimation tasks. TOPIC B—POSE ESTIMATION Gao et al., in their paper ‘Efficient 6D Object Pose Estimation based on Attentive Multi-Scale Contextual Information’, proposed an end-to-end 6D pose estimation network to utilise multi-scale contextual features learnt from two heterogeneous data. First, interesting objects are detected from an RGB-D image using an existing semantic segmentation method. Then, pixel-wise geometric and colour features are learnt from 3D point clouds and 2D images respectively. Next, three pixelwise feature attention mechanism modules are utilised to exploit the inter-channel relationship of multimodal features. Finally, multi-scale features are extracted at three different scales and 6D pose is estimated through a dense regression module. Experimental results conducted on the LineMOD and YCB-Video datasets demonstrate that the proposed method achieves state-of-the-art performances in terms of average point distance and average closest point distance. Liu et al., in their paper ‘Auto Calibration of Multi-Camera System for Human Pose Estimation’, proposed an iterative joint estimation of intrinsic and extrinsic parameters for a multi-camera system. Specifically, keypoints are detected with high confidence to estimate the essential matrix between two cameras, and the valid extrinsic parameters are estimated by assuming that the intrinsic parameters are known a priori. Then, the reconstructed 3D human body coordinates are projected into the pixel coordinate system, and the intrinsic parameters are estimated by minimising the projection errors. The experimental results show that the proposed method achieves better performance than commonly used calibration tools. TOPIC C—POINT CLOUD PROCESSING AND UNDERSTANDING Liu et al., in their paper ‘Point Cloud Completion by Dynamic Transformer with Adaptive Neighbourhood Feature Fusion’, utilised the adaptive neighbourhood feature extraction (ANE) module and genetic hierarchical point generation (GHG) module to accomplish the point cloud completion task. The ANE module selects k nearest points both in the spatial and feature spaces adaptively according to different target shapes. The GHG module generates finer point clouds hierarchically according to the local shape characteristics, and the shape information of current points is transferred to the next stage through a dynamic transformer structure. The experimental results conducted on the Point Completion Network and Completion3D datasets demonstrate the superiority of the proposed method. Wang et al., in their paper ‘PCCN-RE: Point Cloud Colourisation Network Based on Relevance Embedding’, proposed a highly authentic point cloud colorisation network based on conditional generative adversarial (cGANs) networks. The generator network predicts the colours from the coordinates of each point, while the discriminator utilises the coordinates and the generated colours to determine the reality of input colourised point clouds. Three key components are contained in the generator. Specifically, the relevance embedding structure captures the most related local information, the weighted pooling structure aggregates the local features based on the correlation values of the covariance matrix, and the enhanced spatial transform network keeps the point clouds invariant to the geometric transformations based on weighted pooling and maximal pooling. The experimental results show that the proposed method achieves the highest Peak Signal to Noise Ratio and Structural Similarity Index on the ShapeNetCore dataset. Fang et al., in their paper ‘Sparse Point-Voxel Aggregation Network for Efficient Point Cloud Semantic Segmentation’, proposed a sparse point-voxel aggregation network to overcome high computational costs in the point cloud semantic segmentation task. In the encoding layer, the local context features are learnt through a sparse convolutional network performed on the voxelised point cloud, and the individual point features are learnt through multi-layer perceptron (MLP)-based network performed on the original point cloud. In the decoding layer, these two kinds of features are aggregated at different encoding layers through simple MLP layers. The experimental results show that the proposed method achieves state-of-the-art performance on the SemanticKITTI and S3DIS datasets. Wang et al., in their paper ‘Scale Robust Point Matching-Net: End-to-End Scale Point Matching Using Lie Group’, proposed an end-to-end scale point cloud matching network named SRPM-Net based on Lie Group. The extracted pointwise features are composed of point absolute coordinates, relative coordinates and point pair features of neighbouring points, and the local context features are aggregated through an attentive pooling layer. The matching matrix is computed via the exponential map of Lie group, which represents the feature similarity of points in two point clouds. The final transformation estimation problem is transferred as estimating the coefficients of the Lie algebra optimisation problem and is optimised through an iterative linear optimisation approach. The experimental results show that SRPM-Net achieves the best performance on the ModelNet40 and Stanford 3D scanning datasets. SUMMARY/CONCLUSION The papers published in this Special Issue show that traditional topics, such as optical flow and depth estimation, pose estimation, and point cloud processing have developed very fast in recent years. In addition, many topics have emerged in deep learning-based 3D vision, such as multi-task joint learning and multimodality intelligence. Future research in this field is expected to boost the theoretical development and potential applications of 3D vision.
Yulan Guo, Hanyun Wang, Ronald Clark, Stefano Berretti, Mohammed Bennamoun
IET Comput. Vis.3
2022 Orientation Keypoints for 6D Human Pose Estimation
abstract
Most realtime human pose estimation approaches are based on detecting joint positions. Using the detected joint positions, the yaw and pitch of the limbs can be computed. However, the roll along the limb, which is critical for application such as sports analysis and computer animation, cannot be computed as this axis of rotation remains unobserved. In this paper we therefore introduce orientation keypoints, a novel approach for estimating the full position and rotation of skeletal joints, using only single-frame RGB images. Inspired by how motion-capture systems use a set of point markers to estimate full bone rotations, our method uses virtual markers to generate sufficient information to accurately infer rotations with simple post processing. The rotation predictions improve upon the best reported mean error for joint angles by 48% and achieves 93% accuracy across 15 bone rotations. The method also improves the current state-of-the-art results for joint positions by 14% as measured by MPJPE on the principle dataset, and generalizes well to in-the-wild datasets.
Martin Fisch, Ronald Clark
IEEE Trans. Pattern Anal. Mach. Intell.2
2021 TermiNeRF: Ray Termination Prediction for Efficient Neural Rendering
abstract
Volume rendering using neural fields has shown great promise in capturing and synthesizing novel views of 3D scenes. However, this type of approach requires querying the volume network at multiple points along each viewing ray in order to render an image, resulting in very slow rendering times. In this paper, we present a method that overcomes this limitation by learning a direct mapping from camera rays to locations along the ray that are most likely to influence the pixel’s final appearance. Using this approach we are able to render, train and fine-tune a volumetrically-rendered neural field model an order of magnitude faster than standard approaches. Unlike existing methods, our approach works with general volumes and can be trained end-to-end.
Martin Piala, Ronald Clark
3DV2
2021 End-to-End Egospheric Spatial Memory
Daniel Lenton, Stephen James, Ronald Clark, Andrew J. Davison
ICLR3
2021 Unsupervised Path Regression Networks
abstract
We demonstrate that challenging shortest path problems can be solved via direct spline regression from a neural network, trained in an unsupervised manner (i.e. without requiring ground truth optimal paths for training). To achieve this, we derive a geometry-dependent optimal cost function whose minima guarantees collision-free solutions. Our method beats state-of-the-art supervised learning baselines for shortest path planning, with a much more scalable training pipeline, and a significant speedup in inference time.
Michal Pándy, Daniel Lenton, Ronald Clark
IROS3
2020 Towards Consistent Variational Auto-Encoding (Student Abstract)
abstract
Variational autoencoders (VAEs) have been a successful approach to learning meaningful representations of data in an unsupervised manner. However, suboptimal representations are often learned because the approximate inference model fails to match the true posterior of the generative model, i.e. an inconsistency exists between the learnt inference and generative models. In this paper, we introduce a novel consistency loss that directly requires the encoding of the reconstructed data point to match the encoding of the original data, leading to better representations. Through experiments on MNIST and Fashion MNIST, we demonstrate the existence of the inconsistency in VAE learning and that our method can effectively reduce such inconsistency.
Shuyu Lin, Ronald Clark
AAAI3
2020 LaDDer: Latent Data Distribution Modelling with a Generative Prior
Shuyu Lin, Ronald Clark
BMVC2
2020 Scalable Uncertainty for Computer Vision With Functional Variational Inference
abstract
As Deep Learning continues to yield successful applications in Computer Vision, the ability to quantify all forms of uncertainty is a paramount requirement for its safe and reliable deployment in the real-world. In this work, we leverage the formulation of variational inference in function space, where we associate Gaussian Processes (GPs) to both Bayesian CNN priors and variational family. Since GPs are fully determined by their mean and covariance functions, we are able to obtain predictive uncertainty estimates at the cost of a single forward pass through any chosen CNN architecture and for any supervised learning task. By leveraging the structure of the induced covariance matrices, we propose numerically efficient algorithms which enable fast training in the context of high-dimensional tasks such as depth estimation and semantic segmentation. Additionally, we provide sufficient conditions for constructing regression loss functions whose probabilistic counterparts are compatible with aleatoric uncertainty quantification.
Eduardo D. C. Carvalho, Ronald Clark, Andrea Nicastro, Paul H. J. Kelly
CVPR2
2020 Anomaly Detection for Time Series Using VAE-LSTM Hybrid Model
abstract
In this work, we propose a VAE-LSTM hybrid model as an unsupervised approach for anomaly detection in time series. Our model utilizes both a VAE module for forming robust local features over short windows and a LSTM module for estimating the long term correlation in the series on top of the features inferred from the VAE module. As a result, our detection algorithm is capable of identifying anomalies that span over multiple time scales. We demonstrate the effectiveness of our detection algorithm on five real world problems and find our method outperforms three other commonly used detection methods.
Shuyu Lin, Ronald Clark, Robert Birke, Sandro Schönborn, Agathoniki Trigoni, Stephen J. Roberts
ICASSP2
2020 Towards the Probabilistic Fusion of Learned Priors into Standard Pipelines for 3D Reconstruction
abstract
The best way to combine the results of deep learning with standard 3D reconstruction pipelines remains an open problem. While systems that pass the output of traditional multi-view stereo approaches to a network for regularisation or refinement currently seem to get the best results, it may be preferable to treat deep neural networks as separate components whose results can be probabilistically fused into geometry- based systems. Unfortunately, the error models required to do this type of fusion are not well understood, with many different approaches being put forward. Recently, a few systems have achieved good results by having their networks predict probability distributions rather than single values. We propose using this approach to fuse a learned single-view depth prior into a standard 3D reconstruction system. Our system is capable of incrementally producing dense depth maps for a set of keyframes. We train a deep neural network to predict discrete, nonparametric probability distributions for the depth of each pixel from a single image. We then fuse this "probability volume" with another probability volume based on the photometric consistency between subsequent frames and the keyframe image. We argue that combining the probability volumes from these two sources will result in a volume that is better conditioned. To extract depth maps from the volume, we minimise a cost function that includes a regularisation term based on network predicted surface normals and occlusion boundaries. Through a series of experiments, we demonstrate that each of these components improves the overall performance of the system.
Tristan Laidlow, Jan Czarnowski, Andrea Nicastro, Ronald Clark, Stefan Leutenegger
ICRA4
2019 Learning Meshes for Dense Visual SLAM
abstract
Estimating motion and surrounding geometry of a moving camera remains a challenging inference problem. From an information theoretic point of view, estimates should get better as more information is included, such as is done in dense SLAM, but this is strongly dependent on the validity of the underlying models. In the present paper, we use triangular meshes as both compact and dense geometry representation. To allow for simple and fast usage, we propose a view-based formulation for which we predict the in-plane vertex coordinates directly from images and then employ the remaining vertex depth components as free variables. Flexible and continuous integration of information is achieved through the use of a residual based inference technique. This so-called factor graph encodes all information as mapping from free variables to residuals, the squared sum of which is minimised during inference. We propose the use of different types of learnable residuals, which are trained end-to-end to increase their suitability as information bearing models and to enable accurate and reliable estimation. Detailed evaluation of all components is provided on both synthetic and real data which confirms the practicability of the presented approach.
Michael Bloesch, Tristan Laidlow, Ronald Clark, Stefan Leutenegger, Andrew J. Davison
ICCV3
2019 X-Section: Cross-Section Prediction for Enhanced RGB-D Fusion
abstract
Detailed 3D reconstruction is an important challenge with application to robotics, augmented and virtual reality, which has seen impressive progress throughout the past years. Advancements were driven by the availability of depth cameras (RGB-D), as well as increased compute power, e.g.\ in the form of GPUs -- but also thanks to inclusion of machine learning in the process. Here, we propose X-Section, an RGB-D 3D reconstruction approach that leverages deep learning to make object-level predictions about thicknesses that can be readily integrated into a volumetric multi-view fusion process, where we propose an extension to the popular KinectFusion approach. In essence, our method allows to complete shape in general indoor scenes behind what is sensed by the RGB-D camera, which may be crucial e.g.\ for robotic manipulation tasks or efficient scene exploration. Predicting object thicknesses rather than volumes allows us to work with comparably high spatial resolution without exploding memory and training data requirements on the employed Convolutional Neural Networks. In a series of qualitative and quantitative evaluations, we demonstrate how we accurately predict object thickness and reconstruct general 3D scenes containing multiple objects.
Andrea Nicastro, Ronald Clark, Stefan Leutenegger
ICCV2
2019 Learning Object Bounding Boxes for 3D Instance Segmentation on Point Clouds
abstract
We propose a novel, conceptually simple and general framework for instance segmentation on 3D point clouds. Our method, called 3D-BoNet, follows the simple design philosophy of per-point multilayer perceptrons (MLPs). The framework directly regresses 3D bounding boxes for all instances in a point cloud, while simultaneously predicting a point-level mask for each instance. It consists of a backbone network followed by two parallel network branches for 1) bounding box regression and 2) point mask prediction. 3D-BoNet is single-stage, anchor-free and end-to-end trainable. Moreover, it is remarkably computationally efficient as, unlike existing approaches, it does not require any post-processing steps such as non-maximum suppression, feature sampling, clustering or voting. Extensive experiments show that our approach surpasses existing work on both ScanNet and S3DIS datasets while being approximately 10x more computationally efficient. Comprehensive ablation studies demonstrate the effectiveness of our design.
Bo Yang 0027, Ronald Clark, Qingyong Hu, Sen Wang 0002, Andrew Markham, Agathoniki Trigoni
NeurIPS3
2019 Efficient Indoor Positioning with Visual Experiences via Lifelong Learning
abstract
Positioning with visual sensors in indoor environments has many advantages: it doesn’t require infrastructure or accurate maps, and is more robust and accurate than other modalities such as WiFi. However, one of the biggest hurdles that prevents its practical application on mobile devices is the time-consuming visual processing pipeline. To overcome this problem, this paper proposes a novel lifelong learning approach to enable efficient and real-time visual positioning. We explore the fact that when following a previous visual experience for multiple times, one could gradually discover clues on how to traverse it with much less effort, e.g., which parts of the scene are more informative, and what kind of visual elements we should expect. Such second-order information is recorded as parameters, which provide key insights of the context and empower our system to dynamically optimise itself to stay localised with minimum cost. We implement the proposed approach on an array of mobile and wearable devices, and evaluate its performance in two indoor settings. Experimental results show our approach can reduce the visual processing time up to two orders of magnitude, while achieving sub-metre positioning accuracy.
Hongkai Wen 0001, Ronald Clark, Sen Wang 0002, Xiaoxuan Lu 0001, Bowen Du 0002, Wen Hu 0001, Agathoniki Trigoni
IEEE Trans. Mob. Comput.2
2018 Fusion++: Volumetric Object-Level SLAM
abstract
We propose an online object-level SLAM system which builds a persistent and accurate 3D graph map of arbitrary reconstructed objects. As an RGB-D camera browses a cluttered indoor scene, Mask-RCNN instance segmentations are used to initialise compact per-object Truncated Signed Distance Function (TSDF) reconstructions with object size-dependent resolutions and a novel 3D foreground mask. Reconstructed objects are stored in an optimisable 6DoF pose graph which is our only persistent map representation. Objects are incrementally refined via depth fusion, and are used for tracking, relocalisation and loop closure detection. Loop closures cause adjustments in the relative pose estimates of object instances, but no intra-object warping. Each object also carries semantic information which is refined over time and an existence probability to account for spurious instance predictions. We demonstrate our approach on a hand-held RGB-D sequence from a cluttered office scene with a large number and variety of object instances, highlighting how the system closes loops and makes good use of existing objects on repeated loops. We quantitatively evaluate the trajectory error of our system against a baseline approach on the RGB-D SLAM benchmark, and qualitatively compare reconstruction quality of discovered objects on the YCB video dataset. Performance evaluation shows our approach is highly memory efficient and runs online at 4-8Hz (excluding relocalisation) despite not being optimised at the software level.
John McCormac, Ronald Clark, Michael Bloesch, Andrew J. Davison, Stefan Leutenegger
3DV2
2018 InteriorNet: Mega-scale Multi-sensor Photo-realistic Indoor Scenes Dataset
Wenbin Li 0002, Sajad Saeedi G., John McCormac, Ronald Clark, Dimos Tzoumanikas, Yuzhong Huang, Rui Tang 0015, Stefan Leutenegger
BMVC4
2018 CodeSLAM - Learning a Compact, Optimisable Representation for Dense Visual SLAM
abstract
The representation of geometry in real-time 3D perception systems continues to be a critical research issue. Dense maps capture complete surface shape and can be augmented with semantic labels, but their high dimensionality makes them computationally costly to store and process, and unsuitable for rigorous probabilistic inference. Sparse feature-based representations avoid these problems, but capture only partial scene information and are mainly useful for localisation only. We present a new compact but dense representation of scene geometry which is conditioned on the intensity data from a single image and generated from a code consisting of a small number of parameters. We are inspired by work both on learned depth from images, and auto-encoders. Our approach is suitable for use in a keyframe-based monocular dense SLAM system: While each keyframe with a code can produce a depth map, the code can be optimised efficiently jointly with pose variables and together with the codes of overlapping keyframes to attain global consistency. Conditioning the depth map on the image allows the code to only represent aspects of the local geometry which cannot directly be predicted from the image. We explain how to learn our code representation, and demonstrate its advantageous properties in monocular SLAM.
Michael Bloesch, Jan Czarnowski, Ronald Clark, Stefan Leutenegger, Andrew J. Davison
CVPR3
2018 Learning to Solve Nonlinear Least Squares for Monocular Stereo
Ronald Clark, Michael Bloesch, Jan Czarnowski, Stefan Leutenegger, Andrew J. Davison
ECCV (8)1
2017 VINet: Visual-Inertial Odometry as a Sequence-to-Sequence Learning Problem
abstract
In this paper we present an on-manifold sequence-to-sequence learning approach to motion estimation using visual and inertial sensors. It is to the best of our knowledge the first end-to-end trainable method for visual-inertial odometry which performs fusion of the data at an intermediate feature-representation level. Our method has numerous advantages over traditional approaches. Specifically, it eliminates the need for tedious manual synchronization of the camera and IMU as well as eliminating the need for manual calibration between the IMU and camera. A further advantage is that our model naturally and elegantly incorporates domain specific information which significantly mitigates drift. We show that our approach is competitive with state-of-the-art traditional methods when accurate calibration data is available and can be trained to outperform them in the presence of calibration and synchronization errors.
Ronald Clark, Sen Wang 0002, Hongkai Wen 0001, Andrew Markham, Agathoniki Trigoni
AAAI1
2017 VidLoc: A Deep Spatio-Temporal Model for 6-DoF Video-Clip Relocalization
abstract
Machine learning techniques, namely convolutional neural networks (CNN) and regression forests, have recently shown great promise in performing 6-DoF localization of monocular images. However, in most cases image-sequences, rather only single images, are readily available. To this extent, none of the proposed learning-based approaches exploit the valuable constraint of temporal smoothness, often leading to situations where the per-frame error is larger than the camera motion. In this paper we propose a recurrent model for performing 6-DoF localization of video-clips. We find that, even by considering only short sequences (20 frames), the pose estimates are smoothed and the localization error can be drastically reduced. Finally, we consider means of obtaining probabilistic pose estimates from our model. We evaluate our method on openly-available real-world autonomous driving and indoor localization datasets.
Ronald Clark, Sen Wang 0002, Andrew Markham, Agathoniki Trigoni, Hongkai Wen 0001
CVPR1
2017 DeepVO: Towards end-to-end visual odometry with deep Recurrent Convolutional Neural Networks
abstract
This paper studies monocular visual odometry (VO) problem. Most of existing VO algorithms are developed under a standard pipeline including feature extraction, feature matching, motion estimation, local optimisation, etc. Although some of them have demonstrated superior performance, they usually need to be carefully designed and specifically fine-tuned to work well in different environments. Some prior knowledge is also required to recover an absolute scale for monocular VO. This paper presents a novel end-to-end framework for monocular VO by using deep Recurrent Convolutional Neural Networks (RCNNs). Since it is trained and deployed in an end-to-end manner, it infers poses directly from a sequence of raw RGB images (videos) without adopting any module in the conventional VO pipeline. Based on the RCNNs, it not only automatically learns effective feature representation for the VO problem through Convolutional Neural Networks, but also implicitly models sequential dynamics and relations using deep Recurrent Neural Networks. Extensive experiments on the KITTI VO dataset show competitive performance to state-of-the-art methods, verifying that the end-to-end Deep Learning technique can be a viable complement to the traditional VO systems.
Sen Wang 0002, Ronald Clark, Hongkai Wen 0001, Agathoniki Trigoni
ICRA2
2016 Keyframe based large-scale indoor localisation using geomagnetic field and motion pattern
abstract
This paper studies indoor localisation problem by using low-cost and pervasive sensors. Most of existing indoor localisation algorithms rely on camera, laser scanner, floor plan or other pre-installed infrastructure to achieve sub-meter or sub-centimetre localisation accuracy. However, in some circumstances these required devices or information may be unavailable or too expensive in terms of cost or deployment. This paper presents a novel keyframe based Pose Graph Simultaneous Localisation and Mapping (SLAM) method, which correlates ambient geomagnetic field with motion pattern and employs low-cost sensors commonly equipped in mobile devices, to provide positioning in both unknown and known environments. Extensive experiments are conducted in large-scale indoor environments to verify that the proposed method can achieve high localisation accuracy similar to state-of-the-arts, such as vision based Google Project Tango.
Sen Wang 0002, Hongkai Wen 0001, Ronald Clark, Agathoniki Trigoni
IROS3
2015 Robust vision-based indoor localization
abstract
Vision-based positioning has proven to be highly successful and popular in mobile robotics and computer vision applications. These methods have, however, not enjoyed the same popularity in the field of indoor localization.
Ronald Clark, Agathoniki Trigoni, Andrew Markham
IPSN1