Image processing techniques for sector scan sonar
| dc.contributor.advisor | Treurnicht, J. | en_ZA |
| dc.contributor.author | Hendriks, Lukas Anton | en_ZA |
| dc.contributor.other | University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. | |
| dc.date.accessioned | 2009-11-25T13:43:09Z | en_ZA |
| dc.date.accessioned | 2010-06-01T08:50:01Z | |
| dc.date.available | 2009-11-25T13:43:09Z | en_ZA |
| dc.date.available | 2010-06-01T08:50:01Z | |
| dc.date.issued | 2009-12 | |
| dc.description | Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009. | |
| dc.description.abstract | ENGLISH ABSTRACT: Sonars are used extensively for underwater sensing and recent advances in forward-looking imaging sonar have made this type of sonar an appropriate choice for use on Autonomous Underwater Vehicles. The images received from these sonar do however, tend to be noisy and when used in shallow water contain strong bottom reflections that obscure returns from actual targets. The focus of this work was the investigation and development of post-processing techniques to enable the successful use of the sonar images for automated navigation. The use of standard image processing techniques for noise reduction and background estimation, were evaluated on sonar images with varying amounts of noise, as well as on a set of images taken from an AUV in a harbour. The use of multiple background removal and noise reduction techniques on a single image was also investigated. To this end a performance measure was developed, based on the dynamic range found in the image and the uniformity of returned targets. This provided a means to quantitatively compare sets of post-processing techniques and identify the “optimal” processing. The resultant images showed great improvement in the visibility of target areas and the proposed techniques can significantly improve the chances of correct target extraction. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Sonars word algemeen gebruik as onderwater sensors. Onlangse ontwikkelings in vooruit-kykende sonars, maak hierdie tipe sonar ’n goeie keuse vir die gebruik op ’n Outomatiese Onderwater Voertuig. Die beelde wat ontvang word vanaf hierdie sonar neig om egter raserig te wees, en wanneer dit in vlak water gebruik word toon dit sterk bodemrefleksies, wat die weerkaatsings van regte teikens verduister. Die fokus van die werk was die ondersoek en ontwikkeling van naverwerkings tegnieke, wat die sonar beelde bruikbaar maak vir outomatiese navigasie. Die gebruik van standaard beeldverwerkingstegnieke vir ruis-onderdrukking en agtergrond beraming, is geëvalueer aan die hand van sonar beelde met verskillende hoeveelhede ruis, asook aan die hand van ’n stel beelde wat in ’n hawe geneem is. Verdere ondersoek is ingestel na die gebruik van meer as een agtergrond beramings en ruis onderdrukking tegniek op ’n enkele beeld. Hierdie het gelei tot die ontwikkeling van ’n maatstaf vir werkverrigting van toegepaste tegnieke. Hierdie maatstaf gee ’n kwantitatiewe waardering van die verbetering op die oorspronklike beeld, en is gebaseer op die verbetering in dinamiese bereik in die beeld en die uniformiteit van die teiken se weerkaatsing. Hierdie maatstaf is gebruik vir die vergelyking van verskeie tegnieke, en identifisering van die “optimale” verwerking. Die verwerkte beelde het ’n groot verbetering getoon in die sigbaarheid van teikens, en die voorgestelde tegnieke kan ’n betekenisvolle bedrae lewer tot die suksesvolle identifisering van obstruksies. | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/2487 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | Stellenbosch : University of Stellenbosch | |
| dc.rights.holder | University of Stellenbosch | |
| dc.subject | Sonar | en_ZA |
| dc.subject | Image post-processing | en_ZA |
| dc.subject | Clutter removal | en_ZA |
| dc.subject | Autonomous underwater vehicles | en_ZA |
| dc.subject | Theses -- Electrical and electronic engineering | en_ZA |
| dc.subject | Dissertations -- Electrical and electronic engineering | en_ZA |
| dc.subject.lcsh | Submersibles | en_ZA |
| dc.subject.lcsh | Image processing | en_ZA |
| dc.subject.lcsh | Underwater acoustics | en_ZA |
| dc.subject.other | Electrical and Electronic Engineering | en_ZA |
| dc.title | Image processing techniques for sector scan sonar | en_ZA |
| dc.type | Thesis | en_ZA |