Animal Sonar pp 815-821 | Cite as

Echoes from Solid and Hollow Metallic Spheres

  • Theodorus A. W. M. Lanen
  • Cees Kamminga
Part of the NATO ASI Science book series (NSSA, volume 156)


A very successful pattern recognition experiment has been carried out with a dolphin identifying a solid sphere versus a hollow one. Results suggest that the dolphin utilized a time difference cue to distinguish between the two spheres. A theoretical evaluation of the physics of the targets, involving a model of the dolphin sonar, has been carried out. The ensonifying signal follows the model of an elementary signal as proposed by Gabor, i.e. a harmonic signal with a Gaussian envelope. The numerical values of the 3 needed parameters are estimated from the sonar recordings of the live experiment. The target modelling of the sphere is done with the quantities inner-to-outer diameter, density of the metal, and longitudinal and transversal wave velocity. A good match between the computational model and the actual experiment shows up.


Hollow Sphere Dominant Frequency Solid Sphere Transversal Wave Sphere Material 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

  • Theodorus A. W. M. Lanen
    • 1
  • Cees Kamminga
    • 1
  1. 1.Information Theory GroupDelft University of TechnologyDelftthe Netherlands

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