This paper describes an approach to combining range data from both a set of sonar sensors as well as from a directional laser range nder to eeciently take advantage of the characteristics of both types of devices when exploring and mapping unknown worlds. We call our approach \just in time sensing" because it uses the more accurate but constrained laser range sensor only as needed, based upon a...

We present an algorithm to distinguish several types of brick walls, picket fences, and hedges based on the analysis of backscattered sonar echoes. The echo data are acquired by a mobile robot with a single-transducer 50 kHz pulse-echo sonar computer-controlled scanning system packaged as its sensor head. For several locations along a wall, fence, or hedge, a fan of backscatter sonar echoes is ...

This paper describes an approach to combining range data from both a set of sonar sensors as well as from a directional laser range nder to e ciently take advantage of the characteristics of both types of devices when exploring and mapping unknown worlds. We call our approach \just in time sensing" because it uses the more accurate but constrained laser range sensor only as needed, based upon a...

This paper describes an approach to combining range data from both a set of sonar sensors as well as from a directional laser range finder to efficiently take advantage of the characteristics of both types of devices when exploring and mapping unknown worlds. We call our approach “just in time sensing” because it uses the more accurate but constrained laser range sensor only as needed, based up...

This paper advocates the application of sensor fusion for the visualisation of social robotic behaviour. Experiments with the Virtual Reality Workbench integrate the key elements of Virtual Reality and robotics in a coherent and systematic manner. The deliberative focusing of attention and sensor fusion between vision systems and sonar sensors is implemented on autonomous mobile robots function...

The minimum variance (MV) beamformer, also known as the Capon or minimum variance distortionless response (MVDR) beamformer, uses the recorded wavefield to compute a set of optimal weights to be applied to each sensor, before coherently adding the sensor outputs. The weights are chosen such that the variance of the output is minimized while maintaining unit gain in the view direction. The MV be...

We present a robust position tracking method for a mobile robot with seven sonar sensors. The method is based on Hough transform and probability grids. The focus of the paper is on the problem how to handle sparse sensors and noisy data in order to develop a low-cost navigation system for real-world applications. The proposed method consists of three steps. It computes a two-dimensional feature...

This paper describes and evaluates visual looming as a method for monocular range estimation. The looming algorithm is based on the relationship between displacements of the observer relative to an object, and the resulting change in the size of the object’s image on the focal plane of the camera. Though the looming algorithm has been described in detail in prior reports, its usefulness for ine...

The main goal of our work is to have a robot navigating in unknown and not specially structured environments, and performing delivery like tasks. This robot has both unreliable sonar and infrared sensors. To cope with unreliability a sensor fusion method is needed. The main problem when applying classical fusion methods is that there is no a priori model of the environment, just because the rob...

Recent developments in the use of composite ceramics for high frequency arrays have reached the stage where large area, high frequency sonar receiver arrays can be produced cost effectively [1]. Typically these consist of hundreds of individual sensors with excellent element-to-element matching, in both gain and phase, over bandwidths in excess of an octave centred on frequencies in the range 3...