Optical quality assurance of GEM foils

An analysis software was developed for the high aspect ratio optical scanning system in the Detec- tor Laboratory of the University of Helsinki and the Helsinki Institute of Physics. The system is used e.g. in the quality assurance of the GEM-TPC detectors being developed for the beam diagnostics system of the SuperFRS at future FAIR facility. The software was tested by analyzing five CERN standard GEM foils scanned with the optical scanning system. The measurement uncertainty of the diameter of the GEM holes and the pitch of the hole pattern was found to be 0.5 {\mu}m and 0.3 {\mu}m, respectively. The software design and the performance are discussed. The correlation between the GEM hole size distribution and the corresponding gain variation was studied by comparing them against a detailed gain mapping of a foil and a set of six lower precision control measurements. It can be seen that a qualitative estimation of the behavior of the local variation in gain across the GEM foil can be made based on the measured sizes of the outer and inner holes.Comment: 12 pages, 29 figure

WMAP constraints on SUGRA models with non-universal gaugino masses and prospects for direct detection

We discuss constraints on supersymmetric models arising from the relic density measurements of WMAP as well as from direct and precision measurements, LEP, b-sgamma, g-2, Bs-mumu. We consider mSUGRA models and their extensions with non-universal gaugino masses. We find, as commonly known, that the relic density pinpoints towards very specific regions of the mSUGRA models: coannihilation, focus and Heavy Higgs annihilation. The allowed regions widen significantly when varying the top quark mass. Introducing some non-universality in the gaugino masses significantly changes this conclusion as in specific non-universal models the relic density upper limit can be easily satisfied. This occurs with models where M1>M2 at the GUT scale when the LSP has a high wino component. Models where M3<M2 favours the Higgs annihilation channel in large regions of parameter space and at large $\tan\beta$ also favours the annihilation of neutralinos in gauge bosons pairs.We discuss also the potential of direct detection experiments to probe supersymmetric models and point out at the main consequences for colliders based on the mass spectrum. Our calculation of the relic density of neutralinos is based on micrOMEGAs and the SUSY spectrum is generated with SoftSUSYComment: 45 pages, 18 figure

Traffic monitoring using image processing : a thesis presented in partial fulfillment of the requirements for the degree of Master of Engineering in Information and Telecommunications Engineering at Massey University, Palmerston North, New Zealand

Traffic monitoring involves the collection of data describing the characteristics of vehicles and their movements. Such data may be used for automatic tolls, congestion and incident detection, law enforcement, and road capacity planning etc. With the recent advances in Computer Vision technology, videos can be analysed automatically and relevant information can be extracted for particular applications. Automatic surveillance using video cameras with image processing technique is becoming a powerful and useful technology for traffic monitoring. In this research project, a video image processing system that has the potential to be developed for real-time application is developed for traffic monitoring including vehicle tracking, counting, and classification. A heuristic approach is applied in developing this system. The system is divided into several parts, and several different functional components have been built and tested using some traffic video sequences. Evaluations are carried out to show that this system is robust and can be developed towards real-time applications

A new Edge Detector Based on Parametric Surface Model: Regression Surface Descriptor

In this paper we present a new methodology for edge detection in digital images. The first originality of the proposed method is to consider image content as a parametric surface. Then, an original parametric local model of this surface representing image content is proposed. The few parameters involved in the proposed model are shown to be very sensitive to discontinuities in surface which correspond to edges in image content. This naturally leads to the design of an efficient edge detector. Moreover, a thorough analysis of the proposed model also allows us to explain how these parameters can be used to obtain edge descriptors such as orientations and curvatures. In practice, the proposed methodology offers two main advantages. First, it has high customization possibilities in order to be adjusted to a wide range of different problems, from coarse to fine scale edge detection. Second, it is very robust to blurring process and additive noise. Numerical results are presented to emphasis these properties and to confirm efficiency of the proposed method through a comparative study with other edge detectors.Comment: 21 pages, 13 figures and 2 table