Accurate camera position determination by means of moiré pattern analysis
| dc.contributor.advisor | Brink, Willie | en_ZA |
| dc.contributor.advisor | Herbst, B. M. | en_ZA |
| dc.contributor.author | Zuurmond, Gideon Joubert | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Science. Department of Applied Mathematics. | en_ZA |
| dc.date.accessioned | 2015-05-20T09:27:59Z | |
| dc.date.available | 2015-05-20T09:27:59Z | |
| dc.date.issued | 2015-03 | en_ZA |
| dc.description | Thesis (MSc)--Stellenbosch University, 2015. | en_ZA |
| dc.description.abstract | 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. | en_ZA |
| dc.description.abstract | 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 kanmaak vir die koördinate in die twee asse parallel aan die vlakke. Daar word in simulasie getoon hoe hierdie nuwe benadering beduidend beter akkuuraatheid kan bied in vergelyking met konvensionele metodes van benadering. | en_ZA |
| dc.format.extent | v, 59 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/96862 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Moiré patterns | en_ZA |
| dc.subject | Spectral analysis | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.subject | Cameras -- calibration | en_ZA |
| dc.subject | Computer vision | en_ZA |
| dc.title | Accurate camera position determination by means of moiré pattern analysis | en_ZA |
| dc.type | Thesis | en_ZA |