Perception-Failure-Induced Test Scenario Searching via Online Causal Reinforcement Learning

Despite compliance with safety standards such as ISO 26262, the perception systems of autonomous vehicles still face numerous challenges during real-world operation. In this work, we propose a framework to identify safety-critical scenarios specifically induced by perception failures, aiming to support more targeted and effective scenario-based testing. Importantly, the key challenge lies in disentangling whether perception failures directly lead to critical outcomes. To address this, we propose an Online Causal Reinforcement Searching (OCRS) framework that simultaneously performs scenario search and causal reasoning. Focusing on visual unawareness and perception degradation, OCRS employs an LSTM-RNN controller to identify accident-prone scenarios linked to perception failures, which are then verified in a counterfactual world to determine causal responsibility. To improve efficiency, an online scenario classifier with passive-aggressive updates is introduced to dynamically filter out non-critical cases. The experimental results demonstrate both the effectiveness and efficiency of the proposed approach, achieving a 33% reduction in execution time for searchingperception-failure-induced corner cases. Furthermore, we evaluate the method under adverse weather conditions such as snow and fog, confirming that OCRS remains effective in identifying various failure modes.