Detector confidence is often used to decide whether a robot needs another view of a target. We test this signal against detector-free visibility from geometry segmentation. In controlled clutter, Grounding DINO confidence remains nearly constant as target visibility falls from all scenes to one in eight. OWLv2 and SAM 3 retain positive correlations with visibility, but all three detectors lose target-instance localization under heavy occlusion. Grounding DINO reports a hidden target present in about nine of ten scenes by detecting same-category distractors. Consequently, confidence understates the benefit of additional views ($8$ versus $88$ percentage points). In a $40$-scene localization comparison, additional-view selection and fusion increase target localizability from $5\%$ to $100\%$. Experiments cover nine categories, two simulators, and real video. On DAVIS, confidence correlates positively with visible area, yet $99\%$ of occluded frames yield a detection and $94\%$ of those detections miss the tracked target. These results distinguish category presence from target visibility and motivate target-grounded evaluation of active perception.
Yuanzhi He, Victor Romero-Cano, Jiayu Xu, Juan David Hernández, Gualtiero Colombo
Obstacle-aware robotic manipulation can require substantial interaction data when deep reinforcement learning policies are trained from scratch. We study a task decomposition framework combining first-layer critic transfer with staged reward redesign (RR) on a Truncated Quantile Critics (TQC) backbone. Transfer reuses an input representation across tasks, while RR supplies intermediate feedback for Pick-and-Place. Experiments cover Push, Pick-and-Place, and Slide in obstacle-free and single-obstacle PyBullet environments, with three random seeds per setting. On obstacle-aware Push, transfer achieves $0.83\pm0.05$ success against $0.77\pm0.06$ for TQC. On obstacle-aware Slide, it achieves $0.95\pm0.02$ against $0.84\pm0.06$ for SAC, the strongest baseline in that setting. These are gains of $6$ and $11$ percentage points, respectively. RR reduces the target-training steps needed for obstacle-free Pick-and-Place from roughly $0.75$M to $0.20$M. Transfer benefits depend on the route: obstacle-aware Pick-and-Place shows a lower mean than training from scratch. A selected simulated trajectory is executed open-loop on a Franka Emika FR3 as a feasibility demonstration. The study characterizes when a lightweight combination of established transfer and reward-design components helps learning.