Thesis
Investigation of a Bio-Inspired Range finding Algorithm (BIRA) for ultrasonic imaging systems
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2007
- Thesis identifier
- T11898
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- This thesis presents the results of the analysis of the bat auditory system and covers various aspect of bat behaviour of interest to the field of ultrasonic imaging. These small mammals use complex acoustic calls to navigate, identify and catch small fiying prey, with apparent performance surpassing any current man-made systems. Therefore, the study of such mammals can introduce new concepts for ultrasonic imaging. This thesis presents a review of the classification of bats by their acoustic emissions. It gives a detailed description of their acoustic calls and also provides information on the underlying processes involved in the bat auditory system. An analysis of the possible applications of the techniques used by the bats is done, in comparison with current ultrasonic technology. The work describes various approaches to reproduce bat behaviour by giving a detailed description of the concepts and the modelling techniques used. A biologically inspired algorithm, Bio Inspired Range finding Algorithm (BIRA), is developed to mimic the underlying processes involved in the bat auditory system, when forming a detailed acoustic image. This algorithm is inspired from the analysis of previous bat auditory models one developed by Saillant et al. in 1993 named Spectrogram Correlation And Transformation receiver (SCAT) and another one from Matsuo et al in 2004. To fulfill the purpose of this thesis, BIRA is designed as a new way of forming images for ultrasonic systems. For evaluating the performance of the BIRA in an environment similar to any engineering applications, an ultrasonic ranging system has also been designed. This system simulates the interactions between the source/receiver device, the medium of propagation and the target structure. It is used to quantify the axial resolution achieved by the BIRA. In a realistic environment, the BIRA appears to be limited in achieving the resolution of the bats. The results presented in the thesis indicate that the techniques inspired from the bat auditory system, as implemented in the BIRA, do not lead to an improvement in axial resolution in a practical environment. BIRA works well on ideal signals, subject to zero noise and where the signal bandwidth is not constrained by environmental or source/receiver limitations. However when air attenuation is considered, the discrimination techniques used in BIRA fail. Moreover, other well-established techniques, used to enhance the axial resolution, perform better than the BIRA when multiple echoes are considered. The results presented in this thesis question the way bats form an acoustic image and more specifically, the formation of a detailed range-profile image. The results support the assumption that bats may have a simpler detection method, either based on the detection of the first echo or on the detection of other acoustic effects created by a flying insect, such as the wing flutter.
- Resource Type
- DOI
- EThOS ID
- uk.bl.ethos.443116
- Date Created
- 2007
- Former identifier
- 760428
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