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Accurately mapping the course and vegetation along a river is challenging, since overhanging trees block GPS at ground level and occlude the shore line when viewed from higher altitudes. We present a multimodal perception system for the active exploration and mapping of a river from a small rotorcraft. We describe three key components that use computer(More)
— Precise knowledge of a robots's ego-motion is a crucial requirement for higher level tasks like autonomous navigation. Bundle adjustment based monocular visual odometry has proven to successfully estimate the motion of a robot for short sequences, but it suffers from an ambiguity in scale. Hence, approaches that only optimize locally are prone to drift in(More)
— Rivers with heavy vegetation are hard to map from the air. Here we consider the task of mapping their course and the vegetation along the shores with the specific intent of determining river width and canopy height. A complication in such riverine environments is that only intermittent GPS may be available depending on the thickness of the surrounding(More)
Mapping a rivers course and width provides valuable information to help understand the ecology, topology and health of a particular environment. Such maps can also be useful to determine whether specific surface vessels can traverse the rivers. While rivers can be mapped from satellite imagery, the presence of vegetation , sometimes so thick that the canopy(More)
— State estimation for Micro Air Vehicles (MAVs) is challenging because sensing instrumentation carried on-board is severely limited by weight and power constraints. In addition, their use close to and inside structures and vegetation means that GPS signals can be degraded or all together absent. Here we present a navigation system suited for use on MAVs(More)
— Rows of trees such as in orchards, planted in straight parallel lines can provide navigation cues for autonomous machines that operate in between them. When the tree canopies are well managed, tree rows appear similar to corridor walls and a simple 2D sensing scheme suffices. However, when the tree canopies are three dimensional, or ground vegetation(More)
Mapping a river's geometry provides valuable information to help understand the topology and health of an environment and deduce other attributes such as which types of surface vessels could traverse the river. While many rivers can be mapped from satellite imagery, smaller rivers that pass through dense vegetation are occluded. We develop a micro air(More)
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