LiRTest: augmenting LiDAR point clouds for automated testing of autonomous driving systems

With the tremendous advancement of Deep Neural Networks (DNNs), autonomous driving systems (ADS) have achieved significant development and been applied to assist in many safety-critical tasks. However, despite their spectacular progress, several real-world accidents involving autonomous cars even resulted in a fatality. While the high complexity and low interpretability of DNN models, which empowers the perception capability of ADS, make conventional testing techniques inapplicable for the perception of ADS, the existing testing techniques depending on manual data collection and labeling become time-consuming and prohibitively expensive. In this paper, we design and implement LiRTest, the first automated LiDAR-based autonomous vehicles testing tool. LiRTest implements the ADS-specific metamorphic relation and equips affine and weather transformation operators that can reflect the impact of the various environmental factors to implement the relation. We experiment LiRTest with multiple 3D object detection models to evaluate its performance on different tasks. The experiment results show that LiRTest can activate different neurons of the object detection models and effectively detect their erroneous behaviors under various driving conditions. Also, the results confirm that LiRTest can improve the object detection precision by retraining with the generated data.