Robust computer vision systems for autonomous vehicles

04.10.2023 - Three teams have been selected to compete in “The Robust AI Grand Challenge”.

The Robust AI Grand Challenge, organized in collaboration with the Future Systems and Technology Directorate, MINDEF Singapore, and DSO National Laboratories, aims to get researchers and scholars from institutes of higher learning (IHLs) and research institutes (RIs) to develop innovative solutions to overcome the vulnerabilities of artificial intelligence (AI) models in computer vision (CV) systems for autonomous vehicles. Three teams have been selected to compete in the grand challenge – two teams from the Nanyang Technological University (NTU) and one team from the National University of Singapore (NUS). SMU Assistant Professor of Computer Science and Lee Kong Chian Fellow Xie Xiaofei will be competing as part of one of the teams from NTU.

When asked what motivated him to compete in the challenge, Xie replied: “When I was at NTU, I had the opportunity to collaborate with Professor Liu Yang and the other co-principal investigators on multiple research projects. Also, the fields of trustworthy software and AI are aligned with my research interests.” He added: “Another motivational factor for me is the opportunity to build robust AI models and test them in the physical world.

“The accuracy of CV systems has been shown to be compromized following any physical threats or attacks. I believe this is the reason why the Grand Challenge has been designed to challenge researchers to design CV systems for AVs that can recover to at least 80 percent of their original accuracy following the onset of any physical threats or attacks; for example, the sudden swerve of another car towards the AV. While the accuracy of 80 percent has been obtained on certain test benchmarks, to date, this threshold has not been attained with real-world data.”

He continued: “Other than meeting this threshold accuracy metric in the challenge, the teams are required to delve into three specific CV scenarios related to Autonomous Driving systems including their ability to detect objects, provide acceptable estimates of the depth and distance of objects to the AV, as well as categorize each pixel of an image for easy and accurate identification.” Other than Xie, there are six other researchers on this NTU team. They include Liu Yang, Guo Qing, Zhang Tianwei, Chen Lyu, Zhang Hanwang and Dong Jin Song.

To secure a place in the grand challenge, the team has designed four work packages as part of its comprehensive research project, which has just commenced on July 1, 2023, and will take place over three years. The first two years of the project will be spent on developing the optimal CV technology while the third year will be focused on testing the technology in the field.

Work Package 1 is designed to provide a unified and comprehensive AV visual representation. Currently, most of the research on AV representation is centered on uni-directional sensing and object detection in a static or specific situation. Existing AV representations often employ separate models to process and recognize different types of data such as images, Lidar signals that leverage a combination of three-dimensional and laser scanning, or other sensing visual modalities.

While current approaches to AV visual representation work well for the data types that they are designed for, there is a lack of integration of the different data types. This can potentially hamper the overall performance and efficiency of the AV system. For instance, despite having defense mechanisms that are optimized for mitigating attacks targeted at image data, the AV could be susceptible to attacks targeting Lidar signals. This is why this work package is centered on creating a unified multi-view and multi-modal representation that can not only incorporate the detection and consideration of rich information, but also use inputs from different camera lenses, images, and Lidar signals. In so doing, the research team intends to build robust models that can match the constantly changing scenarios, or simulate threats/attacks that occur in the physical world.

Given the complexity and costs associated with conducting experiments in the physical world, Work Package 2 is centered on synthesizing real work threats between the digital world and the physical world. By utilizing the unified representation described in Work Package 1, the research team aims to iterate and evaluate the robustness of the CV models more effectively and efficiently before they are deployed to physical AV systems. In addition, with the unified representation, the research team will be able to simulate changes in weather conditions, modify objects in the scene, or even incorporate other real-world variations such as someone running in front of the AV.

The intent behind Work Package 3 is to integrate the multiple views and modalities by reconstructing the different scenarios to improve the AV's ability to make robust and correct decisions when it is subjected to threats or attacks. The research team will also delve into the concept of adversarial repairing techniques to enhance the resilience of the AV.

Work Package 4 will deep dive into understanding the logic of AI decision-making process. To do this, the research team will first analyze the behaviors of neurons and the respective weightage associated with model predictions – to gain insights into the decision logic employed by the AI system. The researchers will also explore the important features that contribute to the model's predictions, specifically why certain data points are classified as precursors to attacks or threats. This exploration will enable the researchers to understand how the attacks exploit the vulnerabilities of AI decision-making processes.

Once a thorough understanding of the logic of AI decision-making process is obtained, the researchers will move on to enhance the models' robustness against such attacks by adjusting the influence of neurons and/or predicting weightage to build more resilient systems. The outcome from completing the work packages will be a robust technology where the judges will determine which of the three teams would advance to the final stage of the challenge.

When asked what success would look like, Xie answered, “The success of our research will be determined by achieving three key accomplishments. “The first accomplishment will be based on the development of advanced attack and defense techniques that can be used to effectively enhance the robustness of CV systems in both digital and physical worlds. In so doing, we hope to significantly improve the resilience and reliability of CV systems in the face of potential threats. We also want to meet or exceed the threshold of 80 % accuracy recovery of the CV systems following physical threats or attacks.”

He concluded thus: “That said, our ultimate goal is to be one of the driving forces of innovation for the AV and automotive industry. Other than having Desay SV Automotive and CETRAN adopt our technology, it is our aspiration to have other leading AV companies and centers to follow suit as well.” (Source: SMU)

Links: Robust AI Grand Challenge, AI Singapore, Singapore • School of Computing and Information Systems, Singapore Management University, Singapore

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