Sim2Real Lane Segmentation via Domain Adaptation

Posted on July 31, 2025 | by Duckietown Admin

General Information

Title: Simulation to Real Domain Adaptation for Lane Segmentation
Authors: Márton Tim, Márton Szemenyei, Róbert Moni
Institution: Budapest University of Technology and Economics, Budapest, Hungary
Citation: M. Tim, M. Szemenyei and R. Moni, "Simulation to Real Domain Adaptation for Lane Segmentation," 2020 23rd International Symposium on Measurement and Control in Robotics (ISMCR), Budapest, Hungary, 2020, pp. 1-6, doi: 10.1109/ISMCR51255.2020.9263406.

Sim2Real Lane Segmentation via Domain Adaptation

This embodied AI work investigates Sim2Real transfer: the process of applying ML agents trained in simulation to real-world environments, for semantic lane segmentation in mobile robotics using domain adaptation techniques.

The study addresses the distributional shift between synthetic (simulated) and real-world data using unsupervised and semi-supervised learning approaches that minimize the need for manual annotation by learning from unlabeled data or limited labeled samples.

A convolutional neural network (CNN) with an encoder-decoder architecture is trained on labeled synthetic data generated in the Duckietown Gym and adapted to unlabeled real-world images captured in the physical Duckietown setup.

The method integrates:

Feature-level and pixel-level adaptation, aligning internal representations and input appearance between domains to ensure consistent segmentation.
Adversarial training, where a discriminator encourages the CNN to learn domain-invariant features.
Cycle-consistent generative adversarial networks (CycleGANs), which perform image-to-image translation to make synthetic images visually similar to real ones while preserving semantic structure.
Evaluation using mean Intersection over Union (mIoU) and pixel accuracy, both standard metrics for assessing segmentation quality.

The results demonstrate that domain adaptation enables effective Sim2Real transfer for lane detection in Duckietown with minimal supervision advancing the deployment of robust, label-efficient perception systems in embedded robotics and autonomous navigation.

Highlights - Sim2Real lane segmentation via domain adaptation

Here is a visual tour of the implementation of lane segmentation via domain adaptation by the authors. For all the details, check out the full paper.

Abstract

Here is the abstract of the work, directly in the words of the authors:

As the cost of labelling and collecting real world data remains an issue for companies, simulator training and transfer learning slowly evolved to be the foundation of many state-of the-art projects. In this paper these methods are applied in the Duckietown setup where self-driving agents can be developed and tested.

Our aim was to train a selected artificial neural network for right lane segmentation on simulator generated stream of images as a comparison baseline, then use domain adaptation to be more precise and stable in the real environment. We have tested and compared four knowledge transfer methods that included domain transformation using CycleGAN and semi-supervised domain adaptation via Minimax Entropy.

As the latter was previously untested in semantic segmentation according to our best knowledge, we have contributed to showing it is indeed possible and produces promising results. Finally we have shown that it could also create a model that fulfills our performance requirements of stability and accuracy.We show that the selected methods are equally eligible for the simulation to real transfer learning problem, and that the simplest method delivers the best performance.

Conclusion - Sim2Real lane segmentation via domain adaptation

Here is the conclusion according to the authors of this paper:

Our goal was to create a stable and accurate right lane segmentation network by means of simulator data and domain adaptation techniques. We have tested and compared four knowledge transfer methods that included domain transformation using CycleGAN and semi-supervised domain adaptation via Minimax Entropy. We have shown that in the given scenario simulator-trained models have relatively good performance on real images, though their stability is a key weakness.

Our findings demonstrate that domain transformation using CycleGAN has limited applicability in segmentation tasks due to its distorting effect on road geometry, however the similarity between training and testing domains did result in increased stability.

Unfortunately, histogram matching failed in our case to improve on the baseline solution, producing similar results to CycleGAN.

We have observed that one of the simplest domain adaptation methods, source and target combined domain training helped to produce the best performing model according to numerical evaluation.

We implemented and demonstrated how semi-supervised domain adaptation via Minimax Entropy, a complex, entropybased adversarial method is applicable for segmentation tasks.

In the end, all the existing results were compared and evaluated with the conclusion that source and target combined domain training produced the best results of all investigated methods tied with SSDA via Minimax Entropy. Thereby, the usability of the latter method in segmentation tasks has also been proven.

Did this work spark your curiosity?

Check out the following works on vehicle autonomy with Duckietown:

Project Authors

Márton Tim is currently working as a deep learning engineer at Continental, Hungary.

Márton Szemenyei is an Associate Professor at Budapest University of Technology and Economics, Hungary.

Robert Moni is currently working as a Senior Machine Learning Engineer at Continental, Hungary.

Learn more

Duckietown is a platform for creating and disseminating robotics and AI learning experiences.

It is modular, customizable and state-of-the-art, and designed to teach, learn, and do research. From exploring the fundamentals of computer science and automation to pushing the boundaries of knowledge, Duckietown evolves with the skills of the user.

Duckietown Map Coordinate System for Global Localization

Duckiebot Localization with Sensor Fusion in Duckietown

Posted on July 8, 2025 | by Duckietown Admin

Duckiebot Localization with Sensor Fusion in Duckietown

Project Resources

Objective: Demonstrate accurate localization of Duckiebots using visual fiducial markers and sensor fusion in a controlled Duckietown environment.
Approach: Use multi-camera sensor fusion to detect AprilTags and reconstruct a stitched top-down map for Duckiebot pose localization.
Authors: Samuel Neumann, University of Alberta, Canada

Localization with Sensor Fusion in Duckietown - the objectives

The advantage of having multiple sensors on a Duckiebot is that the data provided can be combined to provide additional precision and reduce uncertainty in derived results. This process is generally referred to as sensor fusion, and a typical example is localization, i.e., the problem of finding the pose of the Duckiebot in time, with respect to some reference frame. And if the data is redundant? No problem, just discard it.

In this project, the objective is to implement sensor fusion-based localization and lane-following on a DB21 Duckiebot, integrating odometry (using data from wheel encoders) with visual AprilTag detection for improved positional accuracy.

This process addresses limitations of odometry, i.e., the open-loop reconstruction of the robots’ trajectory using only wheel encoder data in a mathematical approach known as “dead reckoning”, by incorporating AprilTags as global reference landmarks, thereby enhancing spatial awareness in environments where dead reckoning alone is insufficient.

Technical concepts include AprilTag-based localization, PID control for lane following, transform tree management in ROS (tf2), and coordinate frame transformations for pose estimation.

Sensor fusion - visual project highlights

The technical approach and challenges

This approach, at the technical level, involves:

extending ROS-based packages to implement AprilTag detection using the dt-apriltags library,
configuring static transformations for landmark localization in a unified world frame, and
correcting odometry drift by broadcasting transforms from estimated AprilTag poses to the Duckiebot’s base frame.

A full PID controller was moreover implemented, with tunable gains for lateral and heading deviation, and derivative terms were conditionally initialized for stability.

Challenges included:

remapping ROS topics for motor command propagation,
resolving frame connectivity in tf trees,
configuring accurate static transforms for AprilTag landmarks,
debugging quaternion misrepresentation during pose updates, and
correctly applying transform compositions using lookup_transform_full to compute odometry corrections.

Camera and AprilTag coordinate frames used in localization and sensor fusion for pose estimation — AprilTag and Camera Frame Axes for Localization

Duckiebot camera coordinate frame used in localization and sensor fusion for transforming AprilTag detections — Duckiebot Camera Frame Axes for Sensor Fusion

Duckietown global coordinate system used in localization and sensor fusion for world-frame pose calculations — Duckietown Map Coordinate System for Global Localization

Looking for similar projects?

Check out the following works on path planning with Duckietown:

Localization with Sensor Fusion in Duckietown: Authors

Samuel Neumann is a Ph. D. student at the University of Alberta, Canada.

Learn more

Duckietown is a modular, customizable, and state-of-the-art platform for creating and disseminating robotics and AI learning experiences.

Duckietown is designed to teach, learn, and do research: from exploring the fundamentals of computer science and automation to pushing the boundaries of knowledge.

These spotlight projects are shared to exemplify Duckietown’s value for hands-on learning in robotics and AI, enabling students to apply theoretical concepts to practical challenges in autonomous robotics, boosting competence and job prospects.

Interpretable Reinforcement Learning for Visual Policies

Posted on July 2, 2025 | by Duckietown Admin

General Information

Title: Self-Supervised Discovering of Interpretable Features for Reinforcement Learning
Authors: Wenjie Shi, Gao Huang, Shiji Song, Zhuoyuan Wang, Tingyu Lin, Cheng Wu
Institution: Tsinghua University, Beijing, China
Citation: W. Shi, G. Huang, S. Song, Z. Wang, T. Lin and C. Wu, "Self-Supervised Discovering of Interpretable Features for Reinforcement Learning," in IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 44, no. 5, pp. 2712-2724, 1 May 2022, doi: 10.1109/TPAMI.2020.3037898.

Interpretable Reinforcement Learning for Visual Policies

Diagram of a two-stage architecture for Interpretable Reinforcement Learning using Self-Supervised Attention Mechanisms in Duckietown — Figure 1. Two-Stage Framework for Interpretable Reinforcement Learning

Heatmaps showing basic attention patterns for Interpretable Reinforcement Learning using Self-Supervised Attention Mechanisms in Duckietown RL agents — Figure 2. Visual Attention Patterns in Reinforcement Learning

Graph comparing returns for Interpretable Reinforcement Learning with Self-Supervised Attention Mechanisms in Duckietown — Figure 3. Expert vs Mask Policy Return Comparison

Comparison of Interpretable Reinforcement Learning with Self-Supervised Attention Mechanisms applied to Atari and Duckietown tasks — Figure 4. RL Performance on Atari Using Masked Inputs

Saliency map comparison for Interpretable Reinforcement Learning with Self-Supervised Attention Mechanisms in Duckietown and Atari agents — Figure 6. Saliency Map Comparison Across Methods

Example of Interpretable Reinforcement Learning mask evaluation using Self-Supervised Attention Mechanisms in Duckietown — Figure 9. Mask Evaluation Example on Duckietown

Masked state sequences showing PPO, SAC, and TD3 agent behavior in Interpretable Reinforcement Learning with Self-Supervised Attention Mechanisms in Duckietown — Figure 12. Visual Comparison of PPO, SAC, and TD3 Agent Behavior

Masked state sequence comparison of Unet, RefineNet, DeepLab-v3, and FC DenseNet for Interpretable Reinforcement Learning using Self-Supervised Attention Mechanisms in Duckietown — Figure 14. Masked State Visualization Across Actor Architectures

Reinforcement Learning (RL) has enabled solving complex problems, especially in relation to visual perception in robotics. An outstanding challenges is that of allowing humans to make sense of the decision making process, so to enable deployment in safety-critical applications such as, e.g., autonomous driving. This work focuses on the problem of interpretable reinforcement learning in vision-based agents.

In particular, this research introduces a self-supervised framework for interpretable reinforcement learning in vision-based agents. The focus lies in enhancing policy interpretability by generating precise attention maps through Self-Supervised Attention Mechanisms (SSAM).

The method does not rely on external labels and works using data generated by a pretrained RL agent. A self-supervised interpretable network (SSINet) is deployed to identify task-relevant visual features. The approach is evaluated across multiple environments, including Atari and Duckietown.

Key components of the method include:

A two-stage training process using pretrained policies and frozen encoders
Attention masks optimized using behavior resemblance and sparsity constraints
Quantitative evaluation using FOR and BER metrics for attention quality
Comparative analysis with gradient and perturbation-based saliency methods
Application across various architectures and RL algorithms including PPO, SAC, and TD3

The proposed approach isolates relevant decision-making cues, offering insight into agent reasoning. In Duckietown, the framework demonstrates how visual interpretability can aid in diagnosing performance bottlenecks and agent failures, offering a scalable model for interpretable reinforcement learning in autonomous navigation systems.

Highlights - interpretable reinforcement learning for visual policies

Here is a visual tour of the implementation of interpretable reinforcement learning for visual policies by the authors. For all the details, check out the full paper.

Abstract

Here is the abstract of the work, directly in the words of the authors:

Deep reinforcement learning (RL) has recently led to many breakthroughs on a range of complex control tasks. However, the agent’s decision-making process is generally not transparent. The lack of interpretability hinders the applicability of RL in safety-critical scenarios. While several methods have attempted to interpret vision-based RL, most come without detailed explanation for the agent’s behavior. In this paper, we propose a self-supervised interpretable framework, which can discover interpretable features to enable easy understanding of RL agents even for non-experts. Specifically, a self-supervised interpretable network (SSINet) is employed to produce fine-grained attention masks for highlighting task-relevant information, which constitutes most evidence for the agent’s decisions. We verify and evaluate our method on several Atari 2600 games as well as Duckietown, which is a challenging self-driving car simulator environment. The results show that our method renders empirical evidences about how the agent makes decisions and why the agent performs well or badly, especially when transferred to novel scenes. Overall, our method provides valuable insight into the internal decision-making process of vision-based RL. In addition, our method does not use any external labelled data, and thus demonstrates the possibility to learn high-quality mask through a self-supervised manner, which may shed light on new paradigms for label-free vision learning such as self-supervised segmentation and detection.

Conclusion - interpretable reinforcement learning for visual policies

Here is the conclusion according to the authors of this paper:

In this paper, we addressed the growing demand for human-interpretable vision-based RL from a fresh perspective. To that end, we proposed a general self-supervised interpretable framework, which can discover interpretable features for easily understanding the agent’s decision-making process. Concretely, a self-supervised interpretable network (SSINet) was employed to produce high-resolution and sharp attention masks for highlighting task-relevant information, which constitutes most evidence for the agent’s decisions. Then, our method was applied to render empirical evidences about how the agent makes decisions and why the agent performs well or badly, especially when transferred to novel scenes. Overall, our work takes a significant step towards interpretable vision-based RL. Moreover, our method exhibits several appealing benefits. First, our interpretable framework is applicable to any RL model taking as input visual images. Second, our method does not use any external labelled data. Finally, we emphasize that our method demonstrates the possibility to learn high-quality mask through a self-supervised manner, which provides an exciting avenue for applying RL to self automatically labelling and label-free vision learning such as self-supervised segmentation and detection.

Did this work spark your curiosity?

Check out the following works on vehicle autonomy with Duckietown:

Project Authors

Wenjie Shi received the BS degree from the School of Hydropower and Information Engineering, Huazhong University of Science and Technology, Wuhan, China, in 2016. He is currently working toward the Ph.D. degree in control science and engineering from the Department of Automation, Institute of Industrial Intelligence and Systems, Tsinghua University, Beijing, China.

Gao Huang (Member, IEEE) received the B.S. degree in automation from Beihang University, Beijing, China, in 2009, and the Ph.D. degree in automation from Tsinghua University, Beijing, in 2015. He is currently an Associate Professor with the Department of Automation, Tsinghua University.

Shiji Song (Senior Member, IEEE) received the Ph.D. degree in mathematics from the Department of Mathematics, Harbin Institute of Technology, Harbin, China, in 1996. He is currently a Professor at the Department of Automation, Tsinghua University, Beijing, China.

Zhuoyuan Wang (IEEE) is currently a Ph. D. student at Carnegie Mellon University, and holds a B.S. degree in control science and engineering in the Department of Automation, Tsinghua University, Beijing, China.

Tingyu Lin received the B.S. degree and the Ph.D. degree in control system from the School of Automation Science and Electrical Engineering at Beihang University in 2007 and 2014, respectively. He is now a Member of China Simulation Federation (CSF).

Cheng Wu received the M.Sc. degree in electrical engineering from Tsinghua University, Beijing, China, in 1966. He is currently a Professor with the Department of Automation, Tsinghua University.

Learn more

Duckietown is a platform for creating and disseminating robotics and AI learning experiences.

Visual Feedback for Autonomous Navigation in Duckietown

Features for Efficient Autonomous Navigation in Duckietown

Posted on June 28, 2025 | by Duckietown Admin

Features for Efficient Autonomous Navigation in Duckietown

Project Resources

Objective: Improving the range of autonomous behaviors of physical Duckiebots in Duckietown.
Approach: Improving and integrating novel control (pure pursuit), perception (YOLO), and navigation algorithms on the Duckietown out-of-the-box "lane following" visual pipeline for autonomy.
Authors: Servesh Khandwe, Ayush Kumar, and Parth Karkar from the Technical University of Munich, Germany.

Project highlights

Visual Feedback for Autonomous Navigation in Duckietown - the objectives

This project from students at TUM (Technische Universität of Munich) builds on the preexisting Duckietown autonomy stack to add/reintegrate/improve upon much-needed autonomous navigation features: improved control (pure pursuit instead of PID), red stop line detection, AprilTag detection, intersection navigation, and obstacle detection (using YOLO v3), making Duckietowns more complex and interesting!

The resulting agent includes modules for lane following, stop line detection, and intersection handling using AprilTags, following the legacy infrastructure of Duckietown.

The autonomy pipeline relies heavily on vision as the primary means of perception: lane edges are projected from image space to the ground plane using inverse perspective mapping learned after running a camera calibration procedure.

The Duckiebot then estimates a dynamic target point by offsetting yellow or white lane markers depending on visibility. The curvature is computed based on the geometric relation between the Duckiebot and the goal point, and the steering command is derived from this curvature.

The Duckiebot velocity and angular velocity are then modulated using a second-degree polynomial function based on detected path geometry.

Visual input from an onboard monocular camera is processed through a lane filter with adaptive Gaussian variance scaling relative to frame timing.

When running by an intersection, stop lines are detected using HSV color segmentation. AprilTag detection determines intersection decisions, with tag IDs mapped to turn directions.

Every module is implemented as an independent ROS package with dedicated launch files, coordinated via a central launch file. A YOLOv3 object detection model, trained on a custom Duckietown dataset, provides real-time obstacle recognition.

SSD object detection performance for autonomous navigation using pure pursuit in Duckietown — SSD Model Performance (mAP)

Loss graph of SSD model during autonomous navigation training using pure pursuit in Duckietown — SSD Model Loss Over Iterations

SSD-based object detection output in autonomous navigation using pure pursuit in Duckietown — Object Detection in Duckietown

Initial YOLO model label annotations in autonomous navigation using pure pursuit in Duckietown — Labels of the baseline Model

Refined label annotations after YOLO model fine-tuning for autonomous navigation using pure pursuit in Duckietown — Labels of the new fine-tuned Model

Confusion matrix showing classification results of the baseline YOLO model in autonomous navigation using pure pursuit in Duckietown — Confusion Matrix of the baseline Model

Confusion matrix showing improved detection accuracy of the fine-tuned YOLO model in autonomous navigation using pure pursuit in Duckietown — Confusion Matrix of the new finetuned Model

YOLO model output in real-time autonomous navigation using pure pursuit in Duckietown — Model Performance on real Duckietown environment

Annotation format structure used by YOLO for object detection in autonomous navigation using pure pursuit in Duckietown — Annotations format used by YOLO for output

Ground projection technique applied for lane tracking in autonomous navigation using pure pursuit in Duckietown — Ground Projection for Path Tracking

Lane edge detection method supporting autonomous navigation using pure pursuit in Duckietown — Edge Detection of Lane Boundaries

Color-based stop line detection system for autonomous navigation using pure pursuit in Duckietown — Color detector for stop line filter

Real-time bot detection for collision avoidance in autonomous navigation using pure pursuit in Duckietown — Bot detector for Collision avoidance

AprilTag detection system for intersection navigation in autonomous navigation using pure pursuit in Duckietown — April Tag sign detection

The challenges and approach

One major hurdle was integrating object detection models like Single-Shot Detector (SSD) and YOLO with the Duckiebot’s ROS-based camera system.

While the SSD model was trained on a custom Duckietown dataset, ROS publisher-subscriber mismatches prevented live inference. Transitioning to the YOLO model involved adapting annotation formats and re-training for compatibility with the YOLO architecture. In lane following, the default controller from Duckietown demos showed high deviation, prompting the implementation of a modified pure pursuit approach.

Additional challenges arose from limited computational resources on the Duckiebot, with CPU overuse causing processing delays when running all modules concurrently. The approach focused on modular development, isolating lane following, stop line detection, and intersection navigation into separate ROS packages with fine-tuned parameters. The pure pursuit algorithm was adapted for ground-projected lane estimation, dynamic speed control, and target point calculation based on visible lane markers. Integration of AprilTag-based intersection logic and LED signaling provided directional control at intersections.

This structured, iterative methodology enabled real-time, vision-guided behavior while operating within the constraints.

Project Report

Did this work spark your curiosity?

Check out the follow works on path planning with Duckietown:

Visual Feedback for Autonomous Navigation in Duckietown: Authors

Servesh Khandwe is currently working as a Software Engineer at Porsche Digital, Germany.

Ayush Kumar is currently working as a Research Assistant at Fraunhofer IIS, Germany.

Parth Karkar is currently working as an Analytical Consultant at Mutares SE & Co. KGaA, Germany.

Learn more

Duckietown is a modular, customizable, and state-of-the-art platform for creating and disseminating robotics and AI learning experiences.

Duckietown is designed to teach, learn, and do research: from exploring the fundamentals of computer science and automation to pushing the boundaries of knowledge.

Visual Feedback for Lane Tracking in Duckietown

Visual Feedback for Autonomous Lane Tracking in Duckietown

Posted on June 20, 2025 | by Duckietown Admin

General Information

Title: Lane Following with a Duckiebot Vehicle using Visual Feedback
Authors: Oscar Castro, Axel Céspedes, Roosevelt Ubaldo, Oscar E. Ramos
Institution: Universidad de Ingenieria y Tecnologia - UTEC Lima, Peru
Citation: O. Castro, A. Céspedes, R. Ubaldo and O. E. Ramos, "Lane Following with a Duckiebot Vehicle using Visual Feedback," 2019 IEEE Sciences and Humanities International Research Conference (SHIRCON), Lima, Peru, 2019, pp. 1-4, doi: 10.1109/SHIRCON48091.2019.9024875.

Visual Feedback for Autonomous Lane Tracking in Duckietown

How can vehicle autonomy be achieved by relying only on visual feedback from the onboard camera?

This work presents an implementation of lane following for the Duckietbot (DB17) using visual feedback as the only onboard sensor. The approach relies on real-time lane detection, and pose estimation, eliminating the need for wheel encoders.

The onboard computation is provided by a Raspberry Pi, which performs low-level motor control, while high-level image processing and decision-making are offloaded to an external ROS-enabled computer.

The key technical aspects of the implemented autonomy pipeline include:

Camera calibration to correct fisheye lens distortion;
HSV-based image segmentation for lane line detection;
Aerial perspective transformation for geometric consistency;
Histogram-based color separation of continuous and dashed lines;
Piecewise polynomial fitting for path curvature estimation;
Closed-loop motion control based on computed linear and angular velocities.

The methodology demonstrates the feasibility of using camera-based perception to control robot motion in structured environments. By using Duckiebot and Duckietown as the development platform, this work is another example of how to bridge the gap between real-world testing and cost-effective prototyping, making vehicle autonomy research more accessible in educational and research contexts.

Highlights - visual feedback for lane tracking in Duckietown

Here is a visual tour of the implementation of vehicle autonomy by the authors. For all the details, check out the full paper.

Visual feedback communication structure for vehicle autonomy in Duckietown using Duckiebot — ROS Node Communication

Histogram analysis for lane segmentation using visual feedback in Duckiebot for vehicle autonomy in Duckietown — Lane Histogram Segmentation

Visual feedback processing in Duckiebot for vehicle autonomy in Duckietown using HSV filtering and edge detection — HSV and Edge Detection

Polynomial segmentation using visual feedback in Duckiebot for vehicle autonomy in Duckietown — Polynomial Adjustment Techniques

Abstract

Here is the abstract of the work, directly in the words of the authors:

The autonomy of a vehicle can be achieved by a proper use of the information acquired with the sensors. Real-sized autonomous vehicles are expensive to acquire and to test on; however, the main algorithms that are used in those cases are similar to the ones that can be used for smaller prototypes. Due to these budget constraints, this work uses the Duckiebot as a testbed to try different algorithms as a first step to achieve full autonomy. This paper presents a methodology to properly use visual feedback, with the information of the robot camera, in order to detect the lane of a circuit and to drive the robot accordingly.

Conclusion - visual feedback for lane tracking in Duckietown

Here is the conclusion according to the authors of this paper:

Autonomous cars are currently a vast research area. Due to this increase in the interest of these vehicles, having a costeffective way to implement algorithms, new applications, and to test them in a controlled environment will further help to develop this technology. In this sense, this paper has presented a methodology for following a lane using a cost-effective robot, called the Duckiebot, using visual feedback as a guide for the motion. Although the whole system was capable of detecting the lane that needs to be followed, it is still sensitive to illumination conditions. Therefore, in places with a lot of lighting and brightness variations, the lane recognition algorithm can affect the autonomy of the vehicle.
As future work, machine learning, and particularly convolutional neural networks, is devised as a means to develop robust lane detectors that are not sensitive to brightness variation. Moreover, more than one Duckiebot is intended to drive simultaneously in the Duckietown.

Did this work spark your curiosity?

Check out the following works on vehicle autonomy with Duckietown:

Project Authors

Oscar Castro is currently working at Blume, Peru.

Axel Eliam Céspedes Duran is currently working as a Laboratory Professor of the Industrial Instrumentation course at the UTEC – Universidad de Ingeniería y Tecnología, Peru.

Roosevelt Jhans Ubaldo Chavez is currently working as a Laboratory Professor of the Industrial Instrumentation course at the UTEC – Universidad de Ingeniería y Tecnología, Peru.

Oscar E. Ramos is currently working toward the Ph.D. degree in robotics with the Laboratory for Analysis and Architecture of Systems, Centre National de la Recherche Scientifique, University of Toulouse, Toulouse, France.

Learn more

Duckietown is a platform for creating and disseminating robotics and AI learning experiences.

Making robotics in Peru more accessible

Posted on June 20, 2025 | by Federico Tani

Making robotics in Peru more accessible

Nicolas Figueroa, CEO of NFM Robotics and Robotics Lab, shares his vision of making robotics in Peru and Latin America accessible.

Lima, Peru, June 2025: Dr. Nicolas Figueroa talks with us about his goal to make teaching and learning robotics in Peru and Latin America more accessible and efficient, and especially about his mission to strengthen Peruvian national industry through robotics.

Quick links

Bringing cutting edge robotics in Peru

Good morning and thank you for your time. Could you introduce yourself please?

Sure. My name is Nícolas Figueroa. I’m the general manager of NFM Robotics, and I also run a nonprofit initiative called Robotics Lab. I recently defended my thesis, so now I’m officially a doctor!

Through Robotics Lab, we work with universities to promote robotics and robot autonomy education in Latin America, where there is still a significant gap in access to advanced robotics knowledge. I believe Duckietown offers an efficient and accessible way to help bridge this gap.

What can you tell us about your work?

My goal is to build a strong robotics community in Peru, and eventually throughout South America.

I work closely with university student leadership. For example, students form directive committees, presidents, vice presidents, chairs, and they organize conferences, workshops, and talks to promote robotics and robot autonomy knowledge. I maintain close contact with engineering schools in the fields of mechatronics, industrial robotics and electronics.

This connection allows me to support their efforts more effectively, even as an external partner. With NFM Robotics, we are seeing that the Peruvian industry is beginning to explore robotics, but isn’t widely adopted yet. There’s a big opportunity to offer high-level solutions, but we need more people trained in this technology.

Duckietown helps us train teams in ROS and autonomous robotics. These teams can then support industry projects.

So how is Duckietown useful for your work?

Considering that our target are both academic institutions for education, and industry for practical applications, I found Duckietown to be an incredible tool for introducing autonomous robotics. Its hands-on, accessible approach is key to closing the knowledge gap concerning robotics in Peru. When I first looked for platforms to teach autonomous robotics, I found that many options were either too expensive, had limited access, or didn’t support community engagement.

Duckietown stood out as different, it empowers learners and prioritizes impact. That’s why I knew it was the right platform to support our mission at Robotics Lab.

Through Robotics Lab, we work with universities to promote robotics education in Latin America, where there is still a significant gap in access to advanced robotics knowledge. I believe Duckietown offers an efficient and accessible way to help bridge this gap.

Nicolas Figueroa

What is your current focus?

Right now, we are focusing on developing robotics in Peru as a pilot project. We’ve established a presence in five Peruvian universities. But by the end of this year and early next year, we plan to expand to other countries. For example, in May, we hosted a virtual lecture series with speakers from Germany, Italy, Spain, and Estonia. It was our first step in bringing our initiative to a broader international context.

I found Duckietown to be an incredible tool for introducing autonomous robotics. Its hands-on, accessible approach is key to closing the robotics knowledge gap.

Nicolas Figueroa

Did Duckietown satisfy your needs?

Duckietown has become a valuable partner in our region. We’re working to bring this platform to more universities and training centers so more people can explore cutting-edge technology, reduce knowledge gaps, and prepare for Industry 4.0 challenges. We’re proud to be part of the Duckietown ecosystem and to contribute to its growth in Latin America. We hope to foster even more collaboration and opportunity for the next generation of roboticists.

Thank you very much for your time, any final comment?

The idea is to form a group within Robotics Lab to begin introducing autonomous robots and learning more deeply about robotic autonomy. We’re currently in discussions with some university faculties about establishing Duckietown-based laboratories, and we hope to promote our partnership with Duckietown even further.

Learn more about Duckietown

Duckietown enables state-of-the-art robotics and AI learning experiences.

It is designed to help teach, learn, and do research: from exploring the fundamentals of computer science and automation to pushing the boundaries of human knowledge.

Tell us your story

Are you an instructor, learner, researcher or professional with a Duckietown story to tell?

Reach out to us!

Pure Pursuit Lane Following with Obstacle Avoidance

Posted on June 16, 2025 | by Duckietown Admin

Pure Pursuit Lane Following with Obstacle Avoidance

Project Resources

Objective: Develop a lane following and obstacle avoidance system using the pure pursuit control for Duckiebots. (DB18)
Approach: Use an adaptive pure pursuit controller with dynamic speed tuning, integrated with vision-based deep-learning based object detection for obstacle-aware navigation.
Authors: Soroush Saryazdi, Dhaivat Bhatt, Robotics and Embodied AI Lab (REAL), Université de Montréal and is also affiliated with MILA.

Project highlights

Pure Pursuit Lane Following with Obstacle Avoidance - the objectives

Pure pursuit is a geometric path tracking algorithm used in autonomous vehicle control systems. It calculates the curvature of the road ahead by determining a target point on the trajectory and computing the required angular velocity to reach that point based on the vehicle’s kinematics.

Unlike proportional integral derivative (PID) control, which adjusts control outputs based on continuous error correction, pure pursuit uses a lookahead point to guide the vehicle along a trajectory, enabling stable convergence to the path without oscillations. This method avoids direct dependency on derivative or integral feedback, reducing complexity in environments with sparse or noisy error signals.

This project aims to implement a pure pursuit-based lane following system integrated with obstacle avoidance for autonomous Duckiebot navigation. The goal is to enable real-time tracking of lane centerlines while maintaining safety through detection and response to dynamic obstacles such as other Duckiebots or cones.

The pipeline includes a modified ground projection system, an adaptive pure pursuit controller for path tracking, and both image processing and deep learning-based object detection modules for obstacle recognition and avoidance.

Faster RCNN model architecture for pure pursuit and obstacle avoidance in Duckietown object detection — Faster RCNN Architecture with Feature Pyramid Network

Object detection results using Faster RCNN for pure pursuit and obstacle avoidance in Duckietown with bounding boxes for duckiebots and traffic cones — Faster RCNN Detection Output with Bounding Boxes

Duckietown object detection for pure pursuit and obstacle avoidance showing detected duckiebots and cones using deep learning — Detection Results for Obstacle Avoidance in Duckietown

The challenges and approach

The primary challenges in this project include robust target point estimation under variable lighting and environmental conditions, real-time object detection with limited computational resources, and smooth trajectory control in the presence of dynamic obstacles.

The approach involves modular integration of perception, planning, and control subsystems.

For perception, the system uses both classical image processing methods and a trained deep learning model for object detection, enabling redundancy and simulation compatibility.

For planning and control, the pure pursuit controller dynamically adjusts speed and steering based on the estimated target point and obstacle proximity. Target point estimation is achieved through ground projection, a transformation that maps image coordinates to real-world planar coordinates using a calibrated camera model. Real-time parameter tuning and feedback mechanisms are included to handle variations in frame rate and sensor noise.

Obstacle positions are also ground-projected and used to trigger stop conditions within a defined safety zone, ensuring collision avoidance through reactive control.

Looking for similar projects?

Check out the following works on path planning with Duckietown:

Pure Pursuit Lane Following with Obstacle Avoidance: Authors

Soroush Saryazdi is currently leading the Neural Networks team at Matic, supervised by Navneet Dalal.

Dhaivat Bhatt is currently working as a Machine learning research engineer at Samsung AI centre, Toronto.

Learn more

Duckietown is a modular, customizable, and state-of-the-art platform for creating and disseminating robotics and AI learning experiences.

Duckietown is designed to teach, learn, and do research: from exploring the fundamentals of computer science and automation to pushing the boundaries of knowledge.

Reproducible Sim-to-Real Traffic Signal Control Environment

Posted on June 12, 2025 | by Duckietown Admin

General Information

Title: Reproducible and Low-cost Sim-to-Real Environment for Traffic Signal Control
Authors: Yiran Zhang, Khoa Vo, Longchao Da, Tiejin Chen, Xiaoou Liu, Hua Wei
Institution: Arizona State University, USA
Citation: Zhang, Y., Vo, K., Da, L., Chen, T., Liu, X. and Wei, H., 2025, May. Reproducible and Low-cost Sim-to-Real Environment for Traffic Signal Control. In Proceedings of the ACM/IEEE 16th International Conference on Cyber-Physical Systems (with CPS-IoT Week 2025) (pp. 1-2).

Reproducible Sim-to-Real Traffic Signal Control Environment

As urban environments become increasingly populated and automobile traffic soars, with US citizens spending on average 54 hours a year stuck on the roads, active traffic control management promises to mitigate traffic jams while maintaining (or improving) safety.

LibSignal++ is a Duckietown-based testbed for reproducible and low-cost sim-to-real evaluation of traffic signal control (TSC) algorithms. Using Duckietown enables consistent, small-scale deployment of both rule-based and learning-based TSC models.

LibSignal++ integrates visual control through camera-based sensing and object detection via the YOLO-v5 model. It features modular components, including Duckiebots, signal controllers, and an indoor positioning system for accurate vehicle trajectory tracking. The testbed supports dynamic scenario replication by enabling both manual and automated manipulation of sensor inputs and road layouts.

Key aspects of the research include:

Sim-to-real pipeline for Reinforcement Learning (RL)-based traffic signal control training and deployment
Multi-simulator training support with SUMO, CityFlow, and CARLA
Reproducibility through standardized and controllable physical components
Integration of real-world sensors and visual control systems
Comparative evaluation using rule-based policies on 3-way and 4-way intersections

The work concludes with plans to extend to Machine Learning (ML)-based TSC models and further sim-to-real adaptation.

Highlights - Reproducible Sim-to-Real Traffic Signal Control Environment

Here is a visual tour of the sim-to-real work of the authors. For all the details, check out the full paper.

Abstract

Here is the abstract of the work, directly in the words of the authors:

This paper presents a unique sim-to-real assessment environment for traffic signal control (TSC), LibSignal++, featuring a 14-ft by 14-ft scaled-down physical replica of a real-world urban roadway equipped with realistic traffic sensors such as cameras, and actual traffic signal controllers. Besides, it is supported by a precise indoor positioning system to track the actual trajectories of vehicles. To generate various plausible physical conditions that are difficult to replicate with computer simulations, this system supports automatic sensor manipulation to mimic observation changes and also supports manual adjustment of physical traffic network settings to reflect the influence of dynamic changes on vehicle behaviors. This system will enable the assessment of traffic policies that are otherwise extremely difficult to simulate or infeasible for full-scale physical tests, providing a reproducible and low-cost environment for sim-to-real transfer research on traffic signal control problems.

Results

Three traffic control policies were tested over a number of experiment repetitions, evaluating each time traffic throughput, average vehicle waiting times, and vehicle battery consumption. Standard deviations for all policies were found to be within acceptable ranges, leading the authors to confirm the ability of the testbed to deliver reproducible results within controlled environments.

Did this work spark your curiosity?

Check out the follow works on machine learning with Duckietown:

Project Authors

Yiran Zhang is associated with the Arizona State University, USA.

Khoa Vo is associated with the Arizona State University, USA.

Longchao Da is pursuing his Ph.D. at the Arizona State University, USA.

Tiejin Chen is pursuing his Ph.D. at the Arizona State University, USA.

Xiaoou Liu is pursuing her Ph.D. at the Arizona State University, USA.

Hua Wei is an Assistant Professor at the School of Computing and Augmented Intelligence, Arizona State University, USA.

Learn more

Duckietown is a platform for creating and disseminating robotics and AI learning experiences.

Autonomous Navigation System Development in Duckietown

Posted on May 31, 2025 | by Duckietown Admin

Autonomous Navigation System Development in Duckietown

Project Resources

Objective: Enable safe and reliable autonomous navigation for Duckiebots in Duckietowns.
Approach: Use onboard sensors, computer vision, and Dijkstra algorithm to navigate lanes, intersections, and avoid obstacles.
Authors: Julien-Alexandre Bertin Klein, Andrea Pellegrin, Fathia Ismail from the Technical University of Munich, Germany.

Project highlights

Camera and line detector for autonomous navigation — Detecting and stopping at the stop line

AprilTag and line detector views for autonomous navigation — Detecting intersections and executing turns

Dijkstra algorithm map for autonomous navigation — Transforming Roads into a Navigable Network

Autonomous Navigation System Development in Duckietown - the objectives

The primary objective of this project is to develop and refine an Autonomous Navigation System within the Duckietown environment, leveraging ROS-based control and computer vision to enable reliable lane following and safe intersection navigation. This includes calibrating sensor inputs, particularly from the camera, IMU, and encoders, and integrating advanced algorithms such as Dijkstra algorithm for optimal path planning. The project aims to ensure that the Duckiebot can autonomously detect lanes, stop lines, and obstacles while dynamically computing the shortest path to any designated point within the mapped environment. Additionally, the system is designed to transition smoothly between operational states (lane following, intersection handling, and recovery) using a refined Finite State Machine approach, all while maintaining robust communication within the ROS ecosystem.

Project Report

The challenges and approach

The project faced several challenges, beginning with hardware constraints, such as the physical limitations of wheel traction and battery lifespan, which affected motion stability and operational time. The integration of various ROS packages, some with incomplete documentation and inconsistent coding practices, complicated the development of a reliable and maintainable codebase. The method adopted involved precise sensor calibration to ensure accurate perception and control, incorporating camera intrinsic and extrinsic calibration for improved visual data interpretation, and adjusting wheel parameters to maintain balanced motion. The lane following module required parameter tuning for gain, trim, and heading correction to adapt to Duckietown’s environment. The original FSM-based intersection navigation system was re-engineered due to unreliability in node transitions, replaced with a distance-based approach for intersection stops and turns, ensuring deterministic and reliable behavior. Dijkstra’s algorithm was implemented to create a structured graph representation of the city map, enabling dynamic path planning that adapts to real-time inputs from the perception system. Custom web dashboards built with React.js and roslibjs facilitated monitoring and debugging by providing live data feedback and control interfaces. Through this rigorous and iterative process, the project achieved a robust autonomous navigation system capable of precise path planning and safe maneuvering within Duckietown.

Did this work spark your curiosity?

Check out the follow works on path planning with Duckietown:

Autonomous Navigation System Development in Duckietown: Authors

Julien-Alexandre Bertin Klein is currently a Bachelor of Science (BSc.), Information Engineering at the Technical University of Munich, Germany.

Andrea Pellegrin is currently a Bachelor of Science (BSc.), Information Engineering at the Technical University of Munich, Germany.

Fathia Ismail is currently a Bachelor of Science (BSc.), Information Engineering at the Technical University of Munich, Germany.

Learn more

Duckietown is a modular, customizable, and state-of-the-art platform for creating and disseminating robotics and AI learning experiences.

Duckietown is designed to teach, learn, and do research: from exploring the fundamentals of computer science and automation to pushing the boundaries of knowledge.

Adapting World Models with Latent-State Dynamics Residuals

Posted on May 24, 2025 | by Akshet Patel

General Information

Title: Adapting World Models with Latent-State Dynamics Residuals
Authors: JB Lanier, Kyungmin Kim, Armin Karamzade, Yifei Liu, Ankita Sinha, Kat He, Davide Corsi, Roy Fox
Institution: University of California Irvine, USA
Citation: Lanier, J.B., Kim, K., Karamzade, A., Liu, Y., Sinha, A., He, K., Corsi, D. and Fox, R., 2025. Adapting World Models with Latent-State Dynamics Residuals. arXiv preprint arXiv:2504.02252.

Adapting World Models with Latent-State Dynamics Residuals

Training agents for robotics applications requires a substantial amount of data, which is typically costly to collect in the real world. Running simulations is, therefore a logical approach to training agents. But to what degree do simulations provide information that correctly predicts behavior in the real world? In other words, how well do “things” learned in simulation transfer to reality? Sim2Real transfer is an exciting topic and an active area of research.

Simulation-based reinforcement learning often encounters transfer failures due to discrepancies between simulated and real-world dynamics.

This work introduces a method for model adaptation using Latent-State Dynamics Residuals, which correct transition functions in a learned latent space. A latent-variable world model, DRAW, is trained in simulation using variational inference to encode high-dimensional observations into compact multi-categorical latent variables.

The forward dynamics are modeled via autoregressive prediction of latent transitions. A residual learning function is trained on a small, offline real-world dataset without reward supervision to adjust the simulated dynamics. The resulting model, ReDRAW, modifies the forward dynamics logits using residual corrections and enables policy training via actor-critic reinforcement learning on imagined rollouts.

The reward model is reused from the simulation without retraining. To generate diverse training data, the method uses Plan2Explore, which promotes exploration by maximizing model uncertainty. Visual encoders trained in simulation are reused for real-world inputs through zero-shot perception transfer, without fine-tuning.

The approach avoids explicit observation-space correction and operates entirely in the latent space, achieving efficient sim-to-real policy deployment.

Highlights - adapting world models with latent-state dynamics residuals

Here is a visual tour of the sim-to-real work of the authors. For all the details, check out the full paper.

Abstract

Here is the abstract of the work, directly in the words of the authors:

Simulation-to-reality (sim-to-real) reinforcement learning (RL) faces the critical challenge of reconciling discrepancies between simulated and real-world dynamics, which can severely degrade agent performance. A promising approach involves learning corrections to simulator forward dynamics represented as a residual error function, however this operation is impractical with high-dimensional states such as images. To overcome this, we propose ReDRAW, a latent-state autoregressive world model pretrained in simulation and calibrated to target environments through residual corrections of latent-state dynamics rather than of explicit observed states. Using this adapted world model, ReDRAW enables RL agents to be optimized with imagined rollouts under corrected dynamics and then deployed in the real world. In multiple vision-based MuJoCo domains and a physical robot visual lane-following task, ReDRAW effectively models changes to dynamics and avoids overfitting in low data regimes where traditional transfer methods fail.

Limitations and Future Work - adapting world models with latent-state dynamics residuals

Here are the limitations and future work according to the authors of this paper:

A potential limitation with ReDRAWis that it excels at maintaining high target-environment performance over many updates because the residual avoids overfitting due to its low complexity. This suggests that only conceptually simple changes to dynamics may effectively be modeled with low amounts of data, warranting future investigation. We additionally want to explore if residual adaptation methods can be meaningfully applied to foundation world models, efficiently converting them from generators of plausible dynamics to generators of specific dynamics.