Online environment reconstruction for biped navigation

Philipp Michel, Joel Chestnutt, Satoshi Kagami, Koichi Nishiwaki, James Kuffner and Takeo Kanade, 2006

pdficon_largeAs navigation autonomy becomes an increasingly important research topic for biped humanoid robots, efficient approaches to perception and mapping that are suited to the unique characteristics of humanoids and their typical operating environments will be required. This paper presents a system for online environment reconstruction that utilizes both external sensors for global localization, and on-body sensors for detailed local mapping. An external optical motion capture system is used to accurately localize on-board sensors that integrate successive 2D views of a calibrated camera and range measurements from a SwissRanger SR-2 time-of-flight sensor to construct global environment maps in real-time. Environment obstacle geometry is encoded in 2D occupancy grids and 2.5D height maps for navigation planning. We present an on-body implementation for the HRP-2 humanoid robot that, combined with a footstep planner, enables the robot to autonomously traverse dynamic environments containing unpredictably moving obstacles.


3D Object Reconstruction with Heterogeneous Sensor Data

Li Guan, Jean-Sebastien Franco, Marc Pollefeys, 2008

pdficon_largeIn this paper, we reconstruct 3D objects with a heterogeneous sensor network of Time of Flight (ToF) Range Imaging (RIM) sensors and high-res camcorders. With this setup, we first carry out a simple but effective depth calibration for the RIM cameras. We then combine the camcorder silhouette cues and RIM camera depth information, for the reconstruction. Our main contribution is the proposal of a sensor fusion framework so that the computation is general, simple and scalable. Although we only discuss the fusion of conventional cameras and RIM cameras in this paper, the proposed framework can be applied to any vision sensors. This framework uses a space occupancy grid as a probabilistic 3D representation of scene contents. After defining sensing models for each type of sensors, the reconstruction simply is a Bayesian inference problem, and can be solved robustly. The experiments show that the quality of the reconstruction is substantially improved from the noisy depth sensor measurement.