VLDB 2026 Research / reviewers in the wild / expert
Michael Buchholz
dblp:48/10495
· DBLP profile ↗
39ranked-venue papers
0as first author
34since 2021 · last 2026
0000-0001-5973-0794ORCID · corroborated
Domains — the database's venue-derived domains; a paper can count in several
Artificial intelligence and machine learning · 25 · 22 since 2021Databases, data management, data science and information retrieval · 11 · 9 since 2021Systems, architecture and hardware · 3 · 2 since 2021Graphics, computer vision, multimedia, augmented reality and games · 3 · 3 since 2021Applied, interdisciplinary, general and emerging computing · 2 · 2 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | Analysis of Efficient Transmission Methods of Grid Maps for Intelligent Vehicles
Robin Dehler, Dominik Authaler, Aryan Thakur, Thomas Wodtko, Michael Buchholz |
IV | 5 |
| 2026 | Efficient Map-Based Consistency Check Using a Sigma-Point Signed-Distance Estimator
Jasper Wolff, Thomas Wodtko, Michael Buchholz |
IV | 3 |
| 2026 | Toward Intelligent Automated Driving Functionalities for Multipurpose Vehicles in UNICARagil
Timo Woopen, Michael Buchholz, Matti Henning, Charlotte Hermann, Alexandru Kampmann, Christian Kinzig, Bastian Lampe, Martin Lauer, Markus Schön, Raphael van Kempen, Lingguang Wang, Klaus Dietmayer, Lutz Eckstein, Stefan Kowalewski, Christoph Stiller |
Proc. IEEE | 2 |
| 2025 | Online Monitoring for Multi-Object Measurement Model ParametersabstractModel-based multi-sensor multi-object tracking approaches crucially depend on their prediction and measurement models. Typically, the approaches work well if the models and their parameters fit the current situation. For a safe operation, it is, therefore, crucial to continuously monitor them. In general, no performance guarantees for the filter can be made in the case of non-fitting models. On the other hand, if the models match, the mathematical properties of the tracking approach, such as Bayes optimality, apply. Distinguishing the two cases leads to a more interpretable and trustable tracking result and provides useful insights for modules later in the processing chain. This paper proposes two methods for monitoring two different parameters of the multi-object measurement model. The evaluation based on simulated data shows that both methods can detect wrong filter parameters, which enhances the reliability of the tracking approach. Alexander Scheible, Michael Buchholz |
FUSION | 2 |
| 2025 | Dynamic Objective MPC for Motion Planning of Seamless Docking ManeuversabstractAutomated vehicles and logistics robots must often position themselves in narrow environments with high precision in front of a specific target, such as a package or their charging station. Often, these docking scenarios are solved in two steps: path following and rough positioning followed by a high-precision motion planning algorithm. This can generate suboptimal trajectories caused by bad positioning in the first phase and, therefore, prolong the time it takes to reach the goal. In this work, we propose a unified approach, which is based on a Model Predictive Control (MPC) that unifies the advantages of Model Predictive Contouring Control (MPCC) with a Cartesian MPC to reach a specific goal pose. The paper's main contributions are the adaption of the dynamic weight allocation method to reach path ends and goal poses inside driving corridors, and the development of the so-called dynamic objective MPC. The latter is an improvement of the dynamic weight allocation method, which can inherently switch state-dependent from an MPCC to a Cartesian MPC to solve the path-following problem and the high-precision positioning tasks independently of the location of the goal pose seamlessly by one algorithm. This leads to foresighted, feasible, and safe motion plans, which can decrease the mission time and result in smoother trajectories. Oliver Schumann, Michael Buchholz, Klaus Dietmayer |
IV | 2 |
| 2025 | Adaptive Minimal Latency In-Sequence Ordering for Multi-Channel Data Fusion in Autonomous DrivingabstractMany data fusion approaches in autonomous driving assume or require data to arrive in an in-sequence order. However, this can generally not be guaranteed for systems with multiple sensors having different transmission and processing latencies. Additionally, latency itself is performance and safety-critical. To ensure safe and efficient driving, latency must be kept minimal. State-of-the-art approaches artificially delay incoming data in an effort to overcome the sequence issue, which drastically increases latency by waiting. Detailed a-priori information about the sensor and transmission characteristics is required, yet, out-of-sequence data cannot be prevented, leading to data loss. In this work, making statistical assumptions reasonable for autonomous driving sensor configurations, we propose an optimal solution providing both guaranteed upper bounds on the data loss and the induced delay. Based on these assumptions, our approach maintains the optimal latency required to ensure in-sequence data ordering. Additionally, by estimating sensor and system characteristics online, our method adaptively adjusts according to the current situation. We demonstrate the superiority of our approach with an extensive evaluation based on both simulated and real-world data. For the latter, using data from an autonomous vehicle emphasizes the importance of our work for intelligent vehicles. Thomas Wodtko, Alexander Scheible, Dominik Authaler, Michael Buchholz |
IV | 4 |
| 2024 | MGNiceNet: Unified Monocular Geometric Scene Understanding
Markus Schön, Michael Buchholz, Klaus Dietmayer |
ACCV (8) | 2 |
| 2024 | Adaptive Kalman Filtering Based on Subjective Logic Self-AssessmentabstractMonitoring and self-assessment of tracking algorithms are essential in modern automated driving systems. However, the further use of this self-assessment information is another growing and not thoroughly studied area of research. One option is to adapt the parameters configured in the tracking algorithm online to obtain better and more robust tracking results directly. The paper proposes a novel overall concept and framework for adaptive Kalman filtering using subjective logic. Based on a self-assessment method, we present multiple variants of adaptive strategies to adapt the noise assumptions online for Kalman filtering. This paper focuses mainly on adaptation procedures for multi-sensor Kalman filters. The proposed method is evaluated in various experiments and compared with state-of-the-art adaptive Kalman filters. Thomas Griebel, Johannes Müller 0003, Michael Buchholz, Klaus Dietmayer |
FUSION | 3 |
| 2024 | Self-Monitored Clutter Rate Estimation for the Labeled Multi-Bernoulli FilterabstractDecision making in automated vehicles is based on the environment model, which is typically computed by a tracking module from information gathered by sensors. Thus, for safe and robust operation of the vehicle, the assessment of the current quality of the tracking module is crucial. This work makes a step towards this goal by providing a clutter rate estimation method with a self-monitored quality assessment for the labeled multi-Bernoulli filter. The significance of the proposed quality index is demonstrated by comparing it with the actual estimation error calculated with ground truth data. The simulation results show that the developed quality index is a meaningful value that can be computed online without the need for ground truth data. Moreover, it is competitive and closely related to the estimation error. Alexander Scheible, Thomas Griebel, Michael Buchholz |
FUSION | 3 |
| 2024 | Conflict Handling in Time-Dependent Subjective NetworksabstractWith this work, we contribute novel operators and perspectives to the field of subjective logic. We propose a novel multi-source trust revision approach enabling multisource fusion, which considers majority tendencies to mitigate occurring conflicts. For this, the degree of conflict is extended for a multi-source use, which allows our definition of so-called conflict shares. Subsequently, combining our and existing trust revision methods, we propose a generalized trust revision approach. Extending trust revision to subjective networks describing time-dependent processes, we propose the use of sub subjective networks and further the transition to recursive subjective networks. Finally, our trust revision approach and the sub subjective network proposal are evaluated and demonstrated based on experiments, which show conflict handling favoring majorities and an efficient evaluation of time-dependent decision processes. Thomas Wodtko, Thomas Griebel, Alexander Scheible, Michael Buchholz |
FUSION | 4 |
| 2024 | A Graph Neural Network Approach for Solving the Ranked Assignment Problem in Multi-Object TrackingabstractAssociating measurements with tracks is a crucial step in Multi-Object Tracking (MOT) to guarantee the safety of autonomous vehicles. To manage the exponentially growing number of track hypotheses, truncation becomes necessary. In the δ-Generalized Labeled Multi-Bernoulli (δ-GLMB) filter application, this truncation typically involves the ranked assignment problem, solved by Murty’s algorithm or the Gibbs sampling approach, both with limitations in terms of complexity or accuracy, respectively. With the motivation to improve these limitations, this paper addresses the ranked assignment problem arising from data association tasks with an approach that employs Graph Neural Networks (GNNs). The proposed Ranked Assignment Prediction Graph Neural Network (RAPNet) uses bipartite graphs to model the problem, harnessing the computational capabilities of deep learning. The conclusive evaluation compares the RAPNet with Murty’s algorithm and the Gibbs sampler, showing accuracy improvements compared to the Gibbs sampler. Robin Dehler, Martin Herrmann, Jan Strohbeck, Michael Buchholz |
IV | 4 |
| 2024 | Self-Assessment for Multi-Object Tracking Based on Subjective LogicabstractIn automated driving, the safety and robustness of the overall system are among the most important key challenges today. To tackle these safety and robustness challenges, the monitoring and self-assessment of all modules in the automated system is necessary. Tracking surrounding objects as part of the environmental perception is a key module in automated systems. Thus, this work presents a novel overall concept and framework for self-assessment in multi-object tracking based on the subjective logic theory. The self-assessment concept is comprehensively discussed and evaluated by simulations and real-world data of the KITTI dataset, showing the relevance of this proposed method. Thomas Griebel, Nikolas Dehler, Alexander Scheible, Michael Buchholz, Klaus Dietmayer |
IV | 4 |
| 2024 | Infrastructure-based Perception with Cameras and Radars for Cooperative Driving ScenariosabstractRoadside infrastructure has enjoyed widespread adoption for various tasks such as traffic surveillance, traffic monitoring, control of traffic flow, and prioritization of public transit and emergency vehicles. As automated driving functions and vehicle communications continue to be researched, cooperative and connected driving scenarios can now be realized. Cooperative driving, however, imposes stringent environmental perception and model requirements. In particular, road users, including pedestrians and cyclists, must be reliably detected and accurately localized. Furthermore, the perception framework must have low latency to provide up-to-date information. In this work, we present a refined, camera-based reference point detector design that does not rely on annotated infrastructure datasets and incorporates fusion with cost-effective radar sensor data to increase system reliability, if available. The reference point detector design is realized with box and instance segmentation object detector models to extract object ground points. In parallel, objects are extracted from radar target data through a clustering pipeline and fused with camera object detections. To demonstrate the real-world applicability of our approaches for cooperative driving scenarios, we provide an extensive evaluation of data from a real test site. Alexander Tsaregorodtsev, Michael Buchholz, Vasileios Belagiannis |
IV | 2 |
| 2024 | Globally Optimal GNSS Multi-Antenna Lever Arm CalibrationabstractSensor calibration is crucial for autonomous driving, providing the basis for accurate localization and consistent data fusion. Enabling the use of high-accuracy GNSS sensors, this work focuses on the antenna lever arm calibration. We propose a globally optimal multi-antenna lever arm calibration approach based on motion measurements. For this, we derive an optimization method that further allows the integration of a-priori knowledge. Globally optimal solutions are obtained by leveraging the Lagrangian dual problem and a primal recovery strategy. Generally, motion-based calibration for autonomous vehicles is known to be difficult due to cars’ predominantly planar motion. Therefore, we first describe the motion requirements for a unique solution and then propose a planar motion extension to overcome this issue and enable a calibration based on the restricted motion of autonomous vehicles. Last we present and discuss the results of our thorough evaluation. Using simulated and augmented real-world data, we achieve accurate calibration results and fast run times that allow online deployment. Thomas Wodtko, Michael Buchholz |
IV | 2 |
| 2023 | Online Performance Assessment of Multi-Sensor Kalman Filters Based on Subjective LogicabstractOperation monitoring for automation systems requires self-assessment of all data processing modules. In this work, we extend our new self-assessment method for linear Kalman filters based on subjective logic to nonlinear Kalman filtering. Furthermore, we propose novel approaches within this subjective logic-based framework to assess the overall filter performance in multi-sensor systems online, i.e., in real-time without ground truth data. The results of the proposed self-assessment method for nonlinear Kalman filtering are demonstrated through simulation studies, showing advantages compared to classical consistency measures, like the normalized innovation squared. In addition, the results of the proposed online overall filtering assessment for multi-sensor systems can even compete with consistency measures based on ground truth data, which cannot be applied in online applications. Thomas Griebel, Jonas Heinzler, Michael Buchholz, Klaus Dietmayer |
FUSION | 3 |
| 2023 | The Fast Product Multi-Sensor Labeled Multi-Bernoulli FilterabstractThe multi-sensor Labeled Multi-Bernoulli filter has the challenge of relying on the NP-hard multi-sensor update of the Generalized Labeled Multi-Bernoulli filter. This paper proposes the Fast Product Multi-Sensor Labeled Multi-Bernoulli filter, which is a filter for multi-sensor systems that solves this task by performing computationally simpler single-sensor Labeled Multi-Bernoulli filter updates based on a common prediction for each sensor. These single-sensor updates are then fused using a novel and efficient fusion strategy. Furthermore, the proposed filter is based on the Bayes parallel combination rule and can be seen as an efficient approximation of the multi-sensor Labeled Multi-Bernoulli filter. It enables full parallelization of the update step and benefits from sensor order independence compared to Iterated Corrector implementations. As a result, the robustness is increased, which is important for safety reasons, e.g., in autonomous driving. Our approach is evaluated on simulations, and the results are compared to an Iterated Corrector implementation of the Labeled Multi-Bernoulli filter. Charlotte Hermann, Martin Herrmann, Thomas Griebel, Michael Buchholz, Klaus Dietmayer |
FUSION | 4 |
| 2023 | The Product Multi-Sensor Labeled Multi-Bernoulli FilterabstractThe main challenge in random finite set-based multi-sensor multi-object tracking is the NP-hard association of the sensor measurements with the tracks. Using the Bayes parallel combination rule, we have recently proposed the Product Multi-sensor Generalized Labeled Multi-Bernoulli (PM-GLMB) filter, decomposing the multi-sensor update into simpler single-sensor problems with subsequent Bayes optimal fusion. This paper extends the filter to prior densities with Gaussian mixture spatial distributions, which is an inevitable prerequisite for the Product Multi-sensor Labeled Multi-Bernoulli (PM-LMB) filter we propose afterward. Finally, we evaluate the performance of both in a simulation study. In this context, we address the known performance problems of the PM-GLMB filter in crowded situations and show how the PM-LMB filter overcomes these. Martin Herrmann, Tim Luchterhand, Charlotte Hermann, Michael Buchholz |
FUSION | 4 |
| 2023 | The Impact of Frame-Dropping on Performance and Energy Consumption for Multi-Object TrackingabstractThe safety of automated vehicles (AVs) relies on the representation of their environment. Consequently, state-of-the-art AVs employ potent sensor systems to achieve the best possible environment representation at all times. Although these high-performing systems achieve impressive results, they induce significant requirements for the processing capabilities of an AV’s computational hardware components and their energy consumption.To enable a dynamic adaptation of such perception systems based on the situational perception requirements, we introduce a model-agnostic method for the scalable employment of single-frame object detection models using frame-dropping in tracking-by-detection systems. We evaluate our approach on the KITTI 3D Tracking Benchmark, showing that significant energy savings can be achieved at acceptable performance degradation, reaching up to 28% reduction of energy consumption at a performance decline of 6.6% in HOTA score. Matti Henning, Michael Buchholz, Klaus Dietmayer |
IV | 2 |
| 2023 | Extrinsic Infrastructure Calibration Using the Hand-Eye Robot-World FormulationabstractWe propose a certifiably globally optimal approach for solving the hand-eye robot-world problem supporting multiple sensors and targets at once. Further, we leverage this formulation for estimating a geo-referenced calibration of infrastructure sensors. Since vehicle motion recorded by infrastructure sensors is mostly planar, obtaining a unique solution for the respective hand-eye robot-world problem is unfeasible without incorporating additional knowledge. Hence, we extend our proposed method to include a-priori knowledge, i.e., the translation norm of calibration targets, to yield a unique solution. Our approach achieves state-of-the-art results on simulated and real-world data. Especially on real-world intersection data, our approach utilizing the translation norm is the only method providing accurate results. Markus Horn, Thomas Wodtko, Michael Buchholz, Klaus Dietmayer |
IV | 3 |
| 2023 | Automatic Intersection Management in Mixed Traffic Using Reinforcement Learning and Graph Neural NetworksabstractConnected automated driving has the potential to significantly improve urban traffic efficiency, e.g., by alleviating issues due to occlusion. Cooperative behavior planning can be employed to jointly optimize the motion of multiple vehicles. Most existing approaches to automatic intersection management, however, only consider fully automated traffic. In practice, mixed traffic, i.e., the simultaneous road usage by automated and human-driven vehicles, will be prevalent. The present work proposes to leverage reinforcement learning and a graph-based scene representation for cooperative multi-agent planning. We build upon our previous works that showed the applicability of such machine learning methods to fully automated traffic. The scene representation is extended for mixed traffic and considers uncertainty in the human drivers’ intentions. In the simulation-based evaluation, we model measurement uncertainties through noise processes that are tuned using real-world data. The paper evaluates the proposed method against an enhanced first in -first out scheme, our baseline for mixed traffic management. With increasing share of automated vehicles, the learned planner significantly increases the vehicle throughput and reduces the delay due to interaction. Non-automated vehicles benefit virtually alike. Marvin Klimke, Benjamin Völz, Michael Buchholz |
IV | 3 |
| 2023 | Integration of Reinforcement Learning Based Behavior Planning With Sampling Based Motion Planning for Automated DrivingabstractReinforcement learning has received high research interest for developing planning approaches in automated driving. Most prior works consider the end-to-end planning task that yields direct control commands and rarely deploy their algorithm to real vehicles. In this work, we propose a method to employ a trained deep reinforcement learning policy for dedicated high-level behavior planning. By populating an abstract objective interface, established motion planning algorithms can be leveraged, which derive smooth and drivable trajectories. Given the current environment model, we propose to use a built-in simulator to predict the traffic scene for a given horizon into the future. The behavior of automated vehicles in mixed traffic is determined by querying the learned policy. To the best of our knowledge, this work is the first to apply deep reinforcement learning in this manner, and as such lacks a state-of-the-art benchmark. Thus, we validate the proposed approach by comparing an idealistic single-shot plan with cyclic replanning through the learned policy. Experiments with a real testing vehicle on proving grounds demonstrate the potential of our approach to shrink the simulation to real world gap of deep reinforcement learning based planning approaches. Additional simulative analyses reveal that more complex multi-agent maneuvers can be managed by employing the cycling replanning approach. Marvin Klimke, Benjamin Völz, Michael Buchholz |
IV | 3 |
| 2023 | Real-Time Spatial Trajectory Planning for Urban Environments Using Dynamic OptimizationabstractPlanning trajectories for automated vehicles in urban environments requires methods with high generality, long planning horizons, and fast update rates. Using a path-velocity decomposition, we contribute a novel planning framework, which generates foresighted trajectories and can handle a wide variety of state and control constraints effectively. In contrast to related work, the proposed optimal control problems are formulated over space rather than time. This spatial formulation decouples environmental constraints from the optimization variables, which allows the application of simple, yet efficient shooting methods. To this end, we present a tailored solution strategy based on ILQR, in the Augmented Lagrangian framework, to rapidly minimize the trajectory objective costs, even under infeasible initial solutions. Evaluations in simulation and on a full-sized automated vehicle in real-world urban traffic show the real-time capability and versatility of the proposed approach. Jona Ruof, Max Bastian Mertens, Michael Buchholz, Klaus Dietmayer |
IV | 3 |
| 2023 | RT-K-Net: Revisiting K-Net for Real-Time Panoptic SegmentationabstractPanoptic segmentation is one of the most challenging scene parsing tasks, combining the tasks of semantic segmentation and instance segmentation. While much progress has been made, few works focus on the real-time application of panoptic segmentation methods. In this paper, we revisit the recently introduced K-Net architecture. We propose vital changes to the architecture, training, and inference procedure, which massively decrease latency and improve performance. Our resulting RT-K-Net sets a new state-of-the-art performance for real-time panoptic segmentation methods on the Cityscapes dataset and shows promising results on the challenging Mapillary Vistas dataset. On Cityscapes, RT-K-Net reaches 60.2 % PQ with an average inference time of 32 ms for full resolution 1024×2048 pixel images on a single Titan RTX GPU. On Mapillary Vistas, RT-K-Net reaches 33.2 % PQ with an average inference time of 69 ms. Source code is available at https://github.com/markusschoen/RT-K-Net. Markus Schön, Michael Buchholz, Klaus Dietmayer |
IV | 2 |
| 2023 | Automated Static Camera Calibration with Intelligent VehiclesabstractConnected and cooperative driving requires precise calibration of the roadside infrastructure for having a reliable perception system. To solve this requirement in an automated manner, we present a robust extrinsic calibration method for automated geo-referenced camera calibration. Our method requires a calibration vehicle equipped with a combined GNSS/RTK receiver and an inertial measurement unit (IMU) for self-localization. In order to remove any requirements for the target’s appearance and the local traffic conditions, we propose a novel approach using hypothesis filtering. Our method does not require any human interaction with the information recorded by both the infrastructure and the vehicle. Furthermore, we do not limit road access for other road users during calibration. We demonstrate the feasibility and accuracy of our approach by evaluating our approach on synthetic datasets as well as a real-world connected intersection, and deploying the calibration on real infrastructure. Our source code is publicly available1. Alexander Tsaregorodtsev, Adrian Holzbock, Jan Strohbeck, Michael Buchholz, Vasileios Belagiannis |
IV | 4 |
| 2022 | Self-Assessment for Single-Object Tracking in Clutter Using Subjective Logic
Thomas Griebel, Johannes Müller 0003, Paul Geisler, Charlotte Hermann, Martin Herrmann, Michael Buchholz, Klaus Dietmayer |
FUSION | 6 |
| 2022 | Notes on the Product Multi-Sensor Generalized Labeled Multi-Bernoulli Filter and its Implementation
Martin Herrmann, Tim Luchterhand, Charlotte Hermann, Thomas Wodtko, Jan Strohbeck, Michael Buchholz |
FUSION | 6 |
| 2022 | Deep Kernel Learning for Uncertainty Estimation in Multiple Trajectory Prediction NetworksabstractPredicting future paths of vehicles or pedestrians is an essential task for automated vehicles to allow for planning the own trajectory. Using predicted paths, a planning algorithm can, e.g., react to anticipated manoeuvres of other traffic participants. For calculating risks of planned manoeuvres, it is essential that the predicted paths are generated with information about their uncertainty. Since today's state of the art trajectory prediction algorithms are based on deep neural networks (DNNs), the estimation of uncertainty is left to the neural networks as well, which usually provide no means of assessing how the uncertainty estimation works. In this paper, we present a combination of DNNs with Gaussian processes via Deep Kernel Learning (DKL), which combines the ability of DNNs to perform the prediction task with the advantage of Gaussian processes of having more interpretable probabilistic outputs. We propose and evaluate two different variants for the task of multimodal trajectory prediction using Stochastic Variational Gaussian Processes (SVGPs) and the recently proposed regression method Deep Sigma Point Processes (DSPPs), respectively. We evaluate the predictive distributions of both approaches on the publicly available Argoverse Motion Forecasting dataset and compare them to other, purely neural network based methods for uncertainty estimation. Jan Strohbeck, Johannes Müller 0003, Martin Herrmann, Michael Buchholz |
IROS | 4 |
| 2022 | Situation-Aware Environment Perception for Decentralized Automation ArchitecturesabstractAdvances in the field of environment perception for automated agents have resulted in an ongoing increase in generated sensor data. The available computational resources to process these data are bound to become insufficient for real-time applications. Reducing the amount of data to be processed by identifying the most relevant data based on the agents’ situation, often referred to as situation-awareness, has gained increasing research interest, and the importance of complementary approaches is expected to increase further in the near future. In this work, we extend the applicability range of our recently introduced concept for situation-aware environment perception to the decentralized automation architecture of the UNICARagil project. Considering the specific driving capabilities of the vehicle and using real-world data on target hardware in a post-processing manner, we provide an estimate for the daily reduction in power consumption that accumulates to 36.2%. While achieving these promising results, we additionally show the need to consider scalability in data processing in the design of software modules as well as in the design of functional systems if the benefits of situation-awareness shall be leveraged optimally. Matti Henning, Michael Buchholz, Klaus Dietmayer |
IV | 2 |
| 2022 | Cooperative Behavior Planning for Automated Driving Using Graph Neural NetworksabstractUrban intersections are prone to delays and inefficiencies due to static precedence rules and occlusions limiting the view on prioritized traffic. Existing approaches to improve traffic flow, widely known as automatic intersection management systems, are mostly based on non-learning reservation schemes or optimization algorithms. Machine learning-based techniques show promising results in planning for a single ego vehicle. This work proposes to leverage machine learning algorithms to optimize traffic flow at urban intersections by jointly planning for multiple vehicles. Learning-based behavior planning poses several challenges, demanding for a suited input and output representation as well as large amounts of ground-truth data. We address the former issue by using a flexible graph-based input representation accompanied by a graph neural network. This allows to efficiently encode the scene and inherently provide individual outputs for all involved vehicles. To learn a sensible policy, without relying on the imitation of expert demonstrations, the cooperative planning task is considered as a reinforcement learning problem. We train and evaluate the proposed method in an open-source simulation environment for decision making in automated driving. Compared to a first-in-first-out scheme and traffic governed by static priority rules, the learned planner shows a significant gain in flow rate, while reducing the number of induced stops. In addition to synthetic simulations, the approach is also evaluated based on real-world traffic data taken from the publicly available inD dataset. Marvin Klimke, Benjamin Völz, Michael Buchholz |
IV | 3 |
| 2022 | Cooperative Maneuver Planning for Mixed Traffic at Unsignalized Intersections Using Probabilistic PredictionsabstractIntersections are among the scenarios that are most crucial for efficiency and traffic flow on roads. Several approaches to traffic control at intersections exist, each with its own advantages and drawbacks. These days, wireless connections between road users, automated vehicles, and intelligent infrastructure enable new ways of coordinating traffic. However, the gradual deployment of those advanced technologies leads to a heterogeneous mixture of partially automated, connected, and legacy vehicles. Planning and coordinating maneuvers for this mixed traffic is a challenge and subject to current research, as it can achieve significant efficiency improvements in those scenarios. In this paper, we propose a new maneuver planning system for cooperative connected vehicles in mixed traffic at unsignalized intersections, which often occur in urban areas. Our system consists of a probabilistic multi-modal prediction based on a driver model and an efficient optimization algorithm to find the best maneuvers. We present the functionality of our approach and evaluate the impact on traffic efficiency using simulations of two different intersection layouts at various rates of cooperative vehicle penetration. Max Bastian Mertens, Johannes Müller 0003, Michael Buchholz |
IV | 3 |
| 2022 | Motion Planning for Connected Automated Vehicles at Occluded Intersections With Infrastructure SensorsabstractMotion planning at urban intersections that accounts for the situation context, handles occlusions, and deals with measurement and prediction uncertainty is a major challenge on the way to urban automated driving. In this work, we address this challenge with a sampling-based optimization approach. For this, we formulate an optimal control problem that optimizes for low risk and high passenger comfort. The risk is calculated on the basis of the perception information and the respective uncertainty using a risk model. The risk model combines set-based methods and probabilistic approaches. Thus, the approach provides safety guarantees in a probabilistic sense, while for a vanishing risk, the formal safety guarantees of the set-based methods are inherited. By exploring all available behavior options, our approach solves decision making and longitudinal trajectory planning in one step. The available behavior options are provided by a formal representation of the situation context, which is also used to reduce calculation efforts. Occlusions are resolved using the external perception of infrastructure-mounted sensors. Yet, instead of merging external and ego perception with track-to-track fusion, the information is used in parallel. The motion planning scheme is validated through real-world experiments. Johannes Müller 0003, Jan Strohbeck, Martin Herrmann, Michael Buchholz |
IEEE Trans. Intell. Transp. Syst. | 4 |
| 2021 | Globally Optimal Multi-Scale Monocular Hand-Eye Calibration Using Dual QuaternionsabstractIn this work, we present an approach for monocular hand-eye calibration from per-sensor ego-motion based on dual quaternions. Due to non-metrically scaled translations of monocular odometry, a scaling factor has to be estimated in addition to the rotation and translation calibration. For this, we derive a quadratically constrained quadratic program that allows a combined estimation of all extrinsic calibration parameters. Using dual quaternions leads to low run-times due to their compact representation. Our problem formulation further allows to estimate multiple scalings simultaneously for different sequences of the same sensor setup. Based on our problem formulation, we derive both, a fast local and a globally optimal solving approach. Finally, our algorithms are evaluated and compared to state-of-the-art approaches on simulated and real-world data, e.g., the EuRoC MAV dataset. Thomas Wodtko, Markus Horn, Michael Buchholz, Klaus Dietmayer |
3DV | 3 |
| 2021 | MGNet: Monocular Geometric Scene Understanding for Autonomous DrivingabstractWe introduce MGNet, a multi-task framework for monocular geometric scene understanding. We define monocular geometric scene understanding as the combination of two known tasks: Panoptic segmentation and self-supervised monocular depth estimation. Panoptic segmentation captures the full scene not only semantically, but also on an instance basis. Self-supervised monocular depth estimation uses geometric constraints derived from the camera measurement model in order to measure depth from monocular video sequences only. To the best of our knowledge, we are the first to propose the combination of these two tasks in one single model. Our model is designed with focus on low latency to provide fast inference in real-time on a single consumer-grade GPU. During deployment, our model produces dense 3D point clouds with instance aware semantic labels from single high-resolution camera images. We evaluate our model on two popular autonomous driving benchmarks, i.e., Cityscapes and KITTI, and show competitive performance among other real-time capable methods. Source code is available at https://github.com/markusschoen/MGNet. Markus Schön, Michael Buchholz, Klaus Dietmayer |
ICCV | 2 |
| 2021 | DeepSIL: A Software-in-the-Loop Framework for Evaluating Motion Planning Schemes Using Multiple Trajectory Prediction NetworksabstractTesting and verification is still an open issue on the way to fully automated driving. Simulations can help to reduce the required testing efforts, however, classical simulators based on physical models and heuristics, such as the intelligent driver model (IDM), show limited model accuracy on a microscopic scenario level. In turn, learning-based driver models are often capable to predict human driver’s behavior accurately, but are difficult to tailor such that they follow an intended scenario description. In this work, we propose a software-in-the-loop framework to combine a learned model with a rule-based logic layer and a kinematic vehicle model of a classical traffic simulator. Thus, the merits of both, classical simulators and learning-based models are exploited. We demonstrate with a case study of evaluating a motion planning scheme that the simulator fits well with the needs of testing such methods. Furthermore, we show by experiments with real-world traffic data from a traffic surveillance system that the proposed simulator yields realistic behavior of the simulated road users. Jan Strohbeck, Johannes Müller 0003, Adrian Holzbock, Michael Buchholz |
IROS | 4 |
| 2020 | Extended Existence Probability Using Digital Maps for Object VerificationabstractA main task for automated vehicles is an accurate and robust environment perception. Especially, an error-free detection and modeling of other traffic participants is of great importance to drive safely in any situation. For this purpose, multi-object tracking algorithms, based on object detections from raw sensor measurements, are commonly used. However, false object hypotheses can occur due to a high density of different traffic participants in complex, arbitrary scenarios. For this reason, the presented approach introduces a probabilistic model to verify the existence of a tracked object. Therefore, an object verification module is introduced, where the influences of multiple digital map elements on a track's existence are evaluated. Finally, a probabilistic model fuses the various influences and estimates an extended existence probability for every track. In addition, a Bayes Net is implemented as directed graphical model to highlight this work's expandability. The presented approach, reduces the number of false positives, while retaining true positives. Real world data is used to evaluate and to highlight the benefits of the presented approach, especially in urban scenarios. Fabian Gies, Joachim Posselt, Michael Buchholz, Klaus Dietmayer |
FUSION | 3 |
| 2020 | Kalman Filter Meets Subjective Logic: A Self-Assessing Kalman Filter Using Subjective LogicabstractSelf-assessment is a key to safety and robustness in automated driving. In order to design safer and more robust automated driving functions, the goal is to self-assess the performance of each module in a whole automated driving system. One crucial component in automated driving systems is the tracking of surrounding objects, where the Kalman filter is the most fundamental tracking algorithm. For Kalman filters, some classical online consistency measures exist for self-assessment, which are based on classical probability theory. However, these classical approaches lack the ability to measure the explicit statistical uncertainty within the self-assessment, which is an important quality measure, particularly, if only a small number of samples is available for the self-assessment. In this work, we propose a novel online self-assessment method using subjective logic, which is a modern extension of probabilistic logic that explicitly models the statistical uncertainty. Thus, by embedding classical Kalman filtering into subjective logic, our method additionally features an explicit measure for statistical uncertainty in the self-assessment. Thomas Griebel, Johannes Müller 0003, Michael Buchholz, Klaus Dietmayer |
FUSION | 3 |
| 2020 | Multiple Trajectory Prediction with Deep Temporal and Spatial Convolutional Neural NetworksabstractAutomated vehicles need to not only perceive their environment, but also predict the possible future behavior of all detected traffic participants in order to safely navigate in complex scenarios and avoid critical situations, ranging from merging on highways to crossing urban intersections. Due to the availability of datasets with large numbers of recorded trajectories of traffic participants, deep learning based approaches can be used to model the behavior of road users. This paper proposes a convolutional network that operates on rasterized actor-centric images which encode the static and dynamic actor-environment. We predict multiple possible future trajectories for each traffic actor, which include position, velocity, acceleration, orientation, yaw rate and position uncertainty estimates. To make better use of the past movement of the actor, we propose to employ temporal convolutional networks (TCNs) and rely on uncertainties estimated from the previous object tracking stage. We evaluate our approach on the public "Argoverse Motion Forecasting" dataset, on which it won the first prize at the Argoverse Motion Forecasting Challenge, as presented on the NeurIPS 2019 workshop on "Machine Learning for Autonomous Driving". Jan Strohbeck, Vasileios Belagiannis, Johannes Müller 0003, Marcel Schreiber, Martin Herrmann, Daniel Wolf, Michael Buchholz |
IROS | 7 |
| 2019 | A Subjective-Logic-based Reliability Estimation Mechanism for Cooperative Information with Application to IV's SafetyabstractUse of cooperative information, distributed by road-side units, offers large potential for intelligent vehicles (IVs), As vehicle automation progresses and cooperative perception is used to fill the blind spots of onboard sensors, the question of reliability of the data becomes increasingly important in safety considerations (SOTIF, Safety of the Intended Functionality). This paper addresses the problem to estimate the reliability of cooperative information for in-vehicle use. We propose a novel method to infer the reliability of received data based on the theory of Subjective Logic (SL). Using SL, we fuse multiple information sources, which individually only provide mild cues of the reliability, into a holistic estimate, which is statistically sound through an end-to-end modeling within the theory of SL. Using the proposed scheme for probabilistic SL-based fusion, IVs are able to separate faulty from correct data samples with a large margin of safety. Real world experiments show the applicability and effectiveness of our approach. Johannes Müller 0003, Michael Gabb, Michael Buchholz |
IV | 3 |
| 2015 | Optimal parameter selection of a Model Predictive Control algorithm for energy efficient driving of heavy duty vehiclesabstractThis paper presents an improved approach to the problem of energy efficient driving of heavy duty vehicles. The proposed model for a map-based Model Predictive Control (MPC) leads to an underlying Quadratic Programming (QP) optimization problem, allowing computationally efficient and robust solutions. A parameter estimation procedure is developed for a vehicle- and optimization-independent parametrization of the tradeoff between saving energy and keeping a desired vehicle velocity. Extensive simulations on a highway scenario for different optimization parameters give further insight to optimization properties, which can be utilized to enhance control performance. Compared to previous literature, we demonstrate a significant improvement of the computation time to under one-fifth of a millisecond, while maintaining (or even increasing) the fuel consumption reduction, which is 8.1 percent with the proposed approach compared to a standard cruise controller, without a decrease in the average cruising speed. Michael Henzler, Michael Buchholz, Klaus Dietmayer |
Intelligent Vehicles Symposium | 2 |