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You searched for +publisher:"Stellenbosch University" +contributor:("Stellenbosch University. Faculty of Science. Department of Applied Mathematics."). Showing records 1 – 3 of 3 total matches.

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1. Zuurmond, Gideon Joubert. Accurate camera position determination by means of moiré pattern analysis.

Degree: MSc, 2015, Stellenbosch University

ENGLISH ABSTRACT : We introduce a method for determining the position of a camera with accuracy beyond that which is obtainable through conventional methods, using a single image of a specially constructed calibration object. This is achieved by analysing the moiré pattern that emerges when two high spatial frequency patterns are superimposed, such that one pattern on a plane is observed through another pattern on a second, semi-transparent parallel plane, with the geometry of both the patterns and the planes known. Such an object can be created by suspending printed glass over printed paper or by suspending printed glass over a high resolution video display such as an OLED display or LCD. We show how the camera’s coordinate along the axis perpendicular to the planes can be estimated directly from frequency analysis of the moiré pattern relative to a set of guide points in one of the planes. This method does not require any prior camera knowledge. We further show how the choice of the patterns allows, within limits, arbitrary accuracy of this coordinate estimate at the cost of a stricter limit on the span along that coordinate for which the technique is usable. This improved accuracy is illustrated in simulation. With a sufficiently accurate estimate of the camera’s full set of 3D coordinates, obtained by conventional methods, we show how phase analysis of the moiré pattern in relation to the guides allows calculation of a new estimate of position in the two axes parallel to the planes. This new estimate is shown in simulation to offer significant improvement in accuracy.

AFRIKAANSE OPSOMMING : Ons stel ’n metode bekend om die posisie van ’n kamera te bepaal met akkuuraatheid bo dit wat verkrygbaar is uit konvensionele metodes, deur gebruik te maak van ’n spesiaal gekonstrueerde kalibrasievoorwerp. Die metode berus op analise van moiré patrone wat onstaan waneer twee hoë ruimtelike frekwensie patrone oor mekaar neergelê word deurdat een patroon op ’n plat vlak waargeneem word deur ’n tweede patroon op ’n parallelle, gedeeltelik deursigtige vlak, met die geometrie van beide patrone en vlakke bekend. So ’n voorwerp kan geskep word deur ’n spesiaal gedrukte glas vlak te monteer oor gedrukte papier of oor ’n hoë resolusie skerm, soos ’n OLED skermof LCD. Onswys hoe die kamera se koördinaat langs die as loodreg op die vlakke direk uit frekwensie analise van die moiré patroon relatief tot ’n stel gidspunte in een van die vlakke bepaal kan word. Hierdie metode vereis geen vooraf kennis oor die kamera nie. Ons wys verder hoe die keuse van patrone, binne perke, arbitrêre akkuuraatheid in die bepaling van hierdie koördinaat kan verkry ten koste van ’n nouer bruikbare verstek in hierdie koördinaat. Die verbeterde akkuuraatheid is geïllustreer in simulasie. Indien ’n benadering van die kamera se volle stel 3D koördinate met voldoende akkuuraatheid ook beskikbaar is, wys ons ook hoe fase analise van die moiré patroon relatief tot die gidspunte ons in staat stel om’n nuwe benadering te…

Advisors/Committee Members: Brink, Willie, Herbst, Ben, Stellenbosch University. Faculty of Science. Department of Applied Mathematics..

Subjects/Keywords: Moiré patterns; Spectral analysis; UCTD; Cameras  – calibration; Computer vision

Stellenbosch University https://scholar.sun.ac.za CHAPTER 1. INTRODUCTION 2 The method… …extensions on the object and analysis methods. Stellenbosch University https://scholar.sun.ac.za… …the Z -axis. The 4 Stellenbosch University https://scholar.sun.ac.za 5 CHAPTER 2. CAMERA… …K AY  , AZ such that ax = h1 h3 and a y = h2 . h3 Stellenbosch University https… …in the image plane. Stellenbosch University https://scholar.sun.ac.za 7 CHAPTER 2… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Zuurmond, G. J. (2015). Accurate camera position determination by means of moiré pattern analysis. (Masters Thesis). Stellenbosch University. Retrieved from http://hdl.handle.net/10019.1/96862

Chicago Manual of Style (16th Edition):

Zuurmond, Gideon Joubert. “Accurate camera position determination by means of moiré pattern analysis.” 2015. Masters Thesis, Stellenbosch University. Accessed September 30, 2020. http://hdl.handle.net/10019.1/96862.

MLA Handbook (7th Edition):

Zuurmond, Gideon Joubert. “Accurate camera position determination by means of moiré pattern analysis.” 2015. Web. 30 Sep 2020.

Vancouver:

Zuurmond GJ. Accurate camera position determination by means of moiré pattern analysis. [Internet] [Masters thesis]. Stellenbosch University; 2015. [cited 2020 Sep 30]. Available from: http://hdl.handle.net/10019.1/96862.

Council of Science Editors:

Zuurmond GJ. Accurate camera position determination by means of moiré pattern analysis. [Masters Thesis]. Stellenbosch University; 2015. Available from: http://hdl.handle.net/10019.1/96862


Stellenbosch University

2. Holtzhausen, Petrus Jacobus. Video Surveillance Incorporating Pan-Tilt-Zoom Cameras.

Degree: DSc, 2015, Stellenbosch University

ENGLISH ABSTRACT : When trespassers target businesses and homes, outdoor spaces are typically the first point of illegal entry. Camera systems can help secure these environments, but typically many cameras are needed to cover large areas. In practice most camera systems are only used to review events after they have happened. It is however possible to do much more, and we explore the paradigm of active monitoring where cameras detect trespassers and give visual verification of the alarm. This detection needs to be resilient to weather effects and other environmental noise, while running in real-time on high resolution video sequences. Our goal is to replace multiple static cameras with a single Pan-Tilt-Zoom (PTZ) camera that can monitor expansive terrain. These cameras can survey, detect and zoom in on objects of interest. We develop and implement a robust, real-time algorithm based on an interaction framework between an illumination invariant and a color based background model. We also developed and implemented a novel technique where we use optical flow motion vectors to determine the size and shape of the spatial Gaussian kernels in non parametric models. Although computationally more expensive we demonstrate these more sophisticated models can be more robust. These ideas are adapted for PTZ cameras, exploiting their pan, tilt and zoom capabilities. We apply background modeling on panorama images that inform PTZ camera movement. By this we discuss the construction of a system that secures perimeters using zooming camera analytics.

AFRIKAANSE OPSOMMING : Wanneer oortreders besighede en huise onwettig betree, is die buite omgewing tipies die eerste punt van toegang. Kameras kan aansienlik help om hierdie omgewings te beveilig, maar mens kort groot aantal kameras as jy groot spasies wil monitor. Meeste kamera sisteme word ook net gebruik om die gebeurtenisse na die tyd te besigtig. Ons ondersoek die moontlikheid van aktiewe monitering wat oortreders intyds kan identifiseer. Hierdie deteksie moet robuus wees teen weersomstandighede en ander omgewingseffekte, en moet intyds hardloop op hoë resolusie video sekwensies. Die uiteindelike doel is om 'n groot aantal statiese kameras te vervang met een Pan-Tilt-Zoom (PTZ) kamera wat 'n groot terrein kan dek. Hierdie kameras kan rondkyk en in zoem op relevante voorwerpe. Ons begin deur intydse robuuste monitering te verbeter gebaseer op die kombinasie van illuminasie invariante en kleur gebasseerde modelle. Ons stel dan 'n nuwe tegniek voor om optiese vloei vektore te gebruik om Gaussiese verspreidings se vorm en orientasie te bepaal vir nie-parametriese modelle. Ons pas hierdie idees aan vir gebruik op PTZ kameras. Dit behels onder andere die ontwikkeling van panoramiese agtergrond modelle. Ons gebruik die PTZ eienskappe om die opgespoorde indringers in detail te monitor. Van hier kan ons die PTZ kamera se beweging beheer volgens enige deteksies.

Advisors/Committee Members: Herbst, Barend Mattheus, Crnojevic, Vladimir, Brink, Willie, Stellenbosch University. Faculty of Science. Department of Applied Mathematics.

Subjects/Keywords: Spatial Gaussian kernel; Non parametric models; Security cameras - mathematical models; Pan-tilt-zoom; UCTD; Surveillance detection; Cameras  – Calibration; Video surveillance

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Holtzhausen, P. J. (2015). Video Surveillance Incorporating Pan-Tilt-Zoom Cameras. (Thesis). Stellenbosch University. Retrieved from http://hdl.handle.net/10019.1/96653

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Holtzhausen, Petrus Jacobus. “Video Surveillance Incorporating Pan-Tilt-Zoom Cameras.” 2015. Thesis, Stellenbosch University. Accessed September 30, 2020. http://hdl.handle.net/10019.1/96653.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Holtzhausen, Petrus Jacobus. “Video Surveillance Incorporating Pan-Tilt-Zoom Cameras.” 2015. Web. 30 Sep 2020.

Vancouver:

Holtzhausen PJ. Video Surveillance Incorporating Pan-Tilt-Zoom Cameras. [Internet] [Thesis]. Stellenbosch University; 2015. [cited 2020 Sep 30]. Available from: http://hdl.handle.net/10019.1/96653.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Holtzhausen PJ. Video Surveillance Incorporating Pan-Tilt-Zoom Cameras. [Thesis]. Stellenbosch University; 2015. Available from: http://hdl.handle.net/10019.1/96653

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Stellenbosch University

3. Shabangu, Patrick Eminet. Investigation of a simplified open boundary condition for coastal and shelf sea hydrodynamic models.

Degree: MSc, 2015, Stellenbosch University

ENGLISH ABSTRACT : In general, coastal and shelf hydrodynamic modelling is undertaken with limited area numerical models such as Delft3D or Mike 21. To conduct successful numerical simulations these programmes require appropriate boundary conditions. Various options exist to obtain boundary conditions such as Neumann conditions, specifying water levels, specifying velocities and combination of these, amongst others. In this study one specific method is investigated, namely the specification of water levels on all the open boundaries using a "reduced physics" approach. This method may be more appropriate than Neumann conditions when the domain is fairly large and is also of particular interest as it allows measured data to be incorporated in the boundary conditions, although the latter was not considered in this study. The boundary conditions of interest are determined by separating the crossshore and alongshore components of the momentum equations. To justify the separation, the equations of motion are firstly non-dimensionalised to determine the relative importance of various terms and then scaled to determine under which conditions the cross-shore and alongshore components can be solved independently. The efficacy of a computer program, Tilt, to calculate the open boundary conditions have been investigated for a number of idealised cases. Based on an understanding of the underlying physics and scaling assumptions, situations where these open boundary conditions underperformed have been analysed and reasons given for their underperformance. When applied to "real-life" situations it is likely that one or more of the scaling assumptions will be violated. Comment is provided on the likely errors in model simulations should this occur. The main conclusions are that the "reduced physics" approach used in Tilt restricts fairly significantly the range of flow that can be simulated. Should the scaling assumptions underlying Tilt be satisfied, Tilt performs adequately for limited area model simulations of coastal and shelf regions, however there remain some concerns: • The no flux condition at the coast and clamped water level offshore

AFRIKAANSE OPSOMMING : Oor die algemeen word kus en kontinentale bank hidrodinamiese modellering met beperkte area numeriese modelle soos Delft3D of Mike 21 gedoen. Om suksesvolle simulasies te doen, benodig hierdie programme geskikte randwaardes. Daar bestaan verskeie opsies om randwaardes te verkry soon byvoorbeeld Neuman kondisies, spesifisering van watervlakke, spesifisering van snelheid en kombinasies van hierdie. In hierdie studie word een spesifieke metode ondersoek, naamlik om watervlakke op al die oop rande te spesifiseer deur ’n "gereduseerde fisika" benadering te gebruik. Hierdie metode is meer van toepassing as Neuman randwaardes wanneer die modelleringsgebied redelik groot is en ook van spesifieke belang aangesien dit die inkorporering van gemete data in die randwaardes moontlik maak, alhoewel laasgenoemde nie in hierdie studie ondersoek…

Advisors/Committee Members: Smit, G. J. F., Diedericks, G. P. J., Van Ballegooyen, R. C., Stellenbosch University. Faculty of Science. Department of Applied Mathematics..

Subjects/Keywords: Ocean  – Coast boundary condition; Mathematical models  – Computer Programmes; Mathematical models  – Computer software; UCTD; Oceanography  – Mathematical models; Hydrodynamics  – Mathematical models; Hydrodynamics  – Computer programs

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Shabangu, P. E. (2015). Investigation of a simplified open boundary condition for coastal and shelf sea hydrodynamic models. (Masters Thesis). Stellenbosch University. Retrieved from http://hdl.handle.net/10019.1/96839

Chicago Manual of Style (16th Edition):

Shabangu, Patrick Eminet. “Investigation of a simplified open boundary condition for coastal and shelf sea hydrodynamic models.” 2015. Masters Thesis, Stellenbosch University. Accessed September 30, 2020. http://hdl.handle.net/10019.1/96839.

MLA Handbook (7th Edition):

Shabangu, Patrick Eminet. “Investigation of a simplified open boundary condition for coastal and shelf sea hydrodynamic models.” 2015. Web. 30 Sep 2020.

Vancouver:

Shabangu PE. Investigation of a simplified open boundary condition for coastal and shelf sea hydrodynamic models. [Internet] [Masters thesis]. Stellenbosch University; 2015. [cited 2020 Sep 30]. Available from: http://hdl.handle.net/10019.1/96839.

Council of Science Editors:

Shabangu PE. Investigation of a simplified open boundary condition for coastal and shelf sea hydrodynamic models. [Masters Thesis]. Stellenbosch University; 2015. Available from: http://hdl.handle.net/10019.1/96839

.