Deep Reinforcement Learning with Omnidirectional Images: application to UAV Navigation in Forests

Deep Reinforcement Learning (DRL) is highly efficient for solving complex tasks such as drone obstacle avoidance using cameras. However, these methods are often limited by the camera perception capabilities. In this paper, we demonstrate that point-goal navigation performances can be improved by using cameras with a wider Field-Of-View (FOV). To this end, we present a DRL solution based on equirectangular images and demonstrates its relevance, especially compared to its perspective version. Several visual modalities are compared: ground truth depth, RGB, and depth directly estimated from these $360^{\circ}$ RGB images using Deep Learning methods. Next, we propose a spherical adaptation to take into account the spherical distortions of omnidirectional images in the convolutional neural networks (CNNs) used in the actor-critic network and show a significant improvement in navigation performance. Finally, we modify the perspective depth estimation network using this spherical adaptation and demonstrate a further performance improvement.