Three dimensional (3D) shape reconstruction that aims to reconstruct 3D surface of objects using acquired images, is one of the main problems in computer vision. There are many applications of 3D shape reconstruction, from satellite imaging to material sciences, considering a continent on earth or microscopic surface properties of a material. One of these applications is the automated firearm identification that is an old, yet an unsolved problem in forensic science. Firearm evidence matching algorithms rely on the fact that a firearm creates characteristic marks on surfaces of the bullets and the cartridge cases. These marks should be digitized unaffected from different surface material properties of evidences. Accuracy of 3D shape is one of the most important parameters affecting the overall identification performance. A very high resolution, accurate 3D data have to be reconstructed in the order of minutes. Photometric stereo (PS) method is capable of reconstructing high resolution surfaces in a fast manner. But, the metallic material and the surface topology of the firearm evidences generate highlights and shadows on their images that does not comply with the assumptions of conventional PS. In the scope of this work, it is intended to design an accurate, fast and robust 3D shape reconstruction scheme using PS considering highlights and shadows. These new PS procedures to be developed here should not be limited only to the ballistic evidences but they also could be used for a wider range of objects reflection properties and texture. For this purpose, masked PS methods which are quite fast when compared to other approaches, were classified and implemented. Simple additional masking methods are also proposed. A novel weighted PS method, using weighted least square estimation, is presented to eliminate false edges created by the masks. Concurrently, the calibration processes and the illumination configuration were improved. The disturbances due to close light sources were removed by image calibrations. From experimental tests to simulate the light positioning problem, it is concluded that the double zenith illumination configuration have better performance than the optimal single zenith illumination configuration, when the highlights and the shadows are considered. Double zenith illumination configuration results were further improved by the weighted normal PS with a small additional computation cost. All the implemented methods were tested firstly on the controlled environment using synthetic images. Later the same tests were conducted on real objects with varying characteristics as well as the firearm evidences.

The visual appearance of an image is a complex function of factors such as scene geometry, material reflectances and textures, illumination, and the properties of the camera used to capture the image. Understanding how these factors interact to produce an image is a fundamental problem in computer vision and graphics. This dissertation examines two aspects of this problem: models of visual appearance that allow us to recover scene properties from images and videos, and tools that allow users to manipulate visual appearance in images and videos in intuitive ways. In particular, we look at these problems in three different applications. First, we propose techniques for compositing images that differ significantly in their appearance. Our framework transfers appearance between images by manipulating the different levels of a multi-scale decomposition of the image. This allows users to create realistic composites with minimal interaction in a number of different scenarios. We also discuss techniques for compositing and replacing facial performances in videos. Second, we look at the problem of creating high-quality still images from low-quality video clips. Traditional multi-image enhancement techniques accomplish this by inverting the camera’s imaging process. Our system incorporates feature weights into these image models to create results that have better resolution, noise, and blur characteristics, and summarize the activity in the video. Finally, we analyze variations in scene appearance caused by changes in lighting. We develop a model for outdoor scene appearance that allows us to recover radiometric and geometric infor- mation about the scene from images. We apply this model to a variety of visual tasks, including color-constancy, background subtraction, shadow detection, scene reconstruction, and camera geo-location. We also show that the appearance of a Lambertian scene can be modeled as a combi- nation of distinct three-dimensional illumination subspaces — a result that leads to novel bounds on scene appearance, and a robust uncalibrated photometric stereo method. / Engineering and Applied Sciences

Open clusters have long been objects of interest in astronomy. As a good approximation of essentially pure stellar populations, they have proved very useful for studies in a wide range of astrophysically interesting questions, including stellar evolution and atmosphere, the chemical and dynamical evolution of our Galaxy, and the structure of our Galaxy. Of fundamental importance to our understanding of open clusters, as well as many other questions in astrophysics, is the accurate determination of ages. Currently there are two main techniques for independently determining the ages of stellar populations: main sequence evolution theory (via cluster isochrones) and white dwarf cooling theory. Open clusters provide the ideal environment for the calibration of these two important clocks, as well as the unique opportunity to directly compare and refine our understanding of both theories. Here I present a photometric study of six open clusters, including both ground-based data, and new, deep photometric data from the Hubble Space Telescope. From the former I derive main sequence turn off ages, while the latter will be used to search for faint cluster white dwarfs. From these data I measure a white dwarf age for each cluster and directly compare these ages with those I find from the main sequence turn off age. For this analysis I employ a new Bayesian statistical technique that has been developed by our group. Additionally, I use this new technique to explore the feasibility of a new method to determine cluster white dwarf ages from the hot (bright) white dwarfs alone, and its first successful application to the Hyades. / text

Supernovae are cosmic explosions of cataclysmic proportion that signify the death of a star. While being interesting phenomena in their own right, their brightness also make them excellent probes of the early universe. Depending on the type of the progenitor star and the origin of the explosion different subjects can be investigated. In this dissertation the work I have done on the detection, characterisation and rate measurements of supernovae in the Stockholm VIMOS Supernova Search is presented. We have discovered 16 supernovae that exploded billions of years ago (or, equivalently, at high redshift, z). The observed brightness and colour evolution have been used to classify the supernovae into either thermonuclear (type Ia) or core collapse (type II) supernovae. The accuracy of the classification code is high, only about 5% of the supernovae are mistyped, similar to other codes of the same kind. By comparing the observed frequency of supernovae to simulations the underlying supernova rate at these high redshifts have been measured. The main result reported in this thesis is that the core collapse supernova rate at high redshift matches the rates estimated from looking at the star formation history of the universe, and agree well with previous studies. The rate of Ia supernovae at high redshift have been investigated by several projects, our results show a somewhat higher rate of Ia supernovae than expected. Proper estimates of the systematic errors of rate measurements are found to be very important. Furthermore, by using novel techniques for reducing and stacking images, we have obtained a galaxy sample containing approximately 50,000 galaxies. Photometric redshifts have been obtained for most of the galaxies, the resulting accuracy below z=1 is on the order of 10%. The galaxy sample has also been used to find high redshift sources, so called Lyman Break Galaxies, at z=3-5. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Manuscript. Paper 4: Manuscript.

Baigiamajame magistro darbe aprašyta apvaliosios medienos rietuvių fotonuotraukų analizė, siekiant įvertinti medienos rietuvių glaudumo koeficientą. Darbo tikslas – Įvertinti fotometrinio metodo taikymo apvaliosios medienos rietuvių glaudumo koeficiento nustatymui galimybes. Uždaviniai: • Įvertinti atsitiktinių ir sisteminių paklaidų dydžius, gaunamus apvaliosios medienos rietuvių glaudumo koeficientą, nustatant fotometriniu metodu. • Įvertinti fotometrinio metodo paklaidų priklausomybę nuo sortimentų rūšies. • Įvertinti paklaidų priklausomybę nuo medienos rietuvių glaudumo. Tyrimo objektas – į transporto priemonę sukrauti apvaliosios madienos popiermedžiai. Tyrimo metodika Darbe naudoti mokslinio tyrimo metodai: • Dokumentų analizė; • Vaizdų analizė; • Statistinė analizė; • Loginė analizė. Darbo rezultatai – mano pasirinktas fotometrinis metodas, apvaliosios madienos rietuvių glaudumo koeficientui įvertinti, gali būti taikomas. Paklaidos yra daromos tačiau jos nėra esminės. Iš pasirnktų trijų analizuojamojo vaizdo išskyrimo būdų tiksliausi rezultatai buvo stačiakampio forma išskirtas vaizdas. / Digital photographs of spruce and birch bundles were analised by photometric method using ArcView GIS 3.2. program to determine stacking coefficient of wood in the work. The main aim – to determine ability of photometric method to avaluate stacking coefficient of bundles. The main tasks: • To determine randon and systematic bias of photometric method to estimating stacking of wood bundles. • To determine volume of bias, using photometric method, dependents of roundwood species. • To aveluate dependense of errors in stacking coefficients of bundles volume. Research object. –solid wood which is loaded in a bundles of a truck. Methods: • Dokument analysis; • Image analysis; • Statistic analysis; • Logical analysis. Calculations were made using software ArcView GIS 3.2., STATISTICA v6.0 and EXCEL. The main results. photometric method can be applied to timber stacking precision ratios. Articularly accurate are obtained with the bundle of analyzing image maked rectangle.

We investigate the uses of gravitational lensing for analysing the dark matter haloes around galaxies, comparing galaxies within groups and clusters to those in the field. We consider two cases: when only photometric redshift data is available, and when spectroscopic redshift data is available for a sufficiently large sample of galaxies. For the case of data with photometric redshifts, we analyse the CFHTLenS dataset. This dataset is derived from the CFHTLS-Wide survey, and encompasses 154 deg^2 of high-quality shape data. Using the photometric redshifts to estimate local density, we divide the sample of lens galaxies with stellar masses in the range 10^9 Msun to 10^10.5 Msun into those likely to lie in high-density environments (HDE) and those likely to lie in low-density environments (LDE). Through comparison with galaxy catalogues extracted from the Millennium Simulation, we show that the sample of HDE galaxies should primarily (~61%) consist of satellite galaxies in groups, while the sample of LDE galaxies should consist of mostly (~87%) non-satellite (field and central) galaxies. Comparing the lensing signals around samples of HDE and LDE galaxies matched in stellar mass, we show that the subhaloes of HDE galaxies are less massive than those around LDE galaxies by a factor 0.65+/-0.12, significant at the 2.9 sigma level. A natural explanation is that the haloes of satellite galaxies are stripped through tidal effects in the group environment. Our results are consistent with a typical tidal truncation radius of ~40 kpc. For the case of data with spectroscopic redshifts, we analyse the GAMA-I and the ongoing GAMA-II surveys. We demonstrate the possibility of detecting tidal stripping of dark matter subhaloes within galaxy groups using weak gravitational lensing. We have run ray-tracing simulations on galaxy catalogues from the Millennium Simulation to generate mock shape catalogues. The ray-tracing catalogues assume a halo model for galaxies and groups, using various models with different distributions of mass between galaxy and group haloes to simulate different stages of group evolution. Using these mock catalogues, we forecast the lensing signals that will be detected around galaxy groups and satellite galaxies, as well as test two different methods for isolating the satellites' lensing signals. A key challenge is to determine the accuracy to which group centres can be identified. We show that with current and ongoing surveys, it will possible to detect stripping in groups of mass 10^12 Msun to 10^15 Msun.

The Herschel Space Observatory (Herschel), a flagship mission of the European Space Agency (ESA), is comprised of three cryogenically cooled instruments commissioned to explore the far-infrared/submillimetre universe. Herschel's remote orbit at the second Lagrangian point (L2) of the Sun-Earth system, and its cryogenic payload, impose a need for thorough instrument characterization and rigorous testing as there will be no possibility for any servicing after launch. The Spectral and Photometric Imaging Receiver (SPIRE) is one of the instrument payloads aboard Herschel and consists of a three band imaging photometer and a two band imaging spectrometer. The imaging spectrometer on SPIRE consists of a Mach-Zehnder (MZ)-Fourier transform spectrometer (FTS) coupled with bolometric detector arrays to form an imaging FTS (IFTS). This thesis presents experiments conducted to verify the performance of an IFTS system from a space based platform, i.e. the use of the SPIRE IFTS within the Herschel space observatory. Prior to launch, the SPIRE instrument has undergone a series of performance verification tests conducted at the Rutherford Appleton Laboratory (RAL) near Oxford, UK. Canada is involved in the SPIRE project through provision of instrument development hardware and software, mission flight software, and support personnel. Through this thesis project I have been stationed at RAL for a period spanning fifteen months to participate in the development, performance verification, and characterization of both the SPIRE FTS and photometer instruments. This thesis discusses Fourier transform spectroscopy and related FTS data process ing (Chapter 2). Detailed discussions are included on the spectral phase related to the FTS beamsplitter (Chapter 3), the imaging aspects of the SPIRE IFTS instrument (Chapter 4), and the noise characteristics of the SPIRE bolometer detector arrays as measured using the SPIRE IFTS (Chapter 5). This thesis presents results from experiments performed both on site at the RAL Space Science and Technology Department (SSTD) Assembly Integration Verification (AIV) instrument test facility as well as from the Astronomical Instrumentation Group (AIG) research laboratories within the Department of Physics & Astronomy at the University of Lethbridge. / xxiii, 243 leaves : ill. (some col.) ; 29 cm

The Spectral and Photometric Imaging Receiver (SPIRE) is one of three scientific instruments on the European Space Agency's (ESA's) Herschel Space Observatory (HSO). The medium resolution spectroscopic capabilities of SPIRE are provided by an imaging Fourier transform spectrometer (IFTS). A software simulator of the SPIRE IFTS was written to generate realistic data products, making use of available qualification and test data. We present the design and implementation of the simulator. Component and end-to-end simulations were compared to results from the first SPIRE instrument proto-flight model (PFMI) test campaign conducted at the Rutherford Appleton Laboratory (RAL) in Oxford, England in 2005. Final characterization of the simulator involved the determination of astronomical quantities from the synthetic data products of a simple molecular cloud. / xix, 213 leaves : ill. (some col.) ; 29 cm.

The European Space Agency's Herschel Space Observatory is comprised of three cryogenically cooled instruments commissioned to explore the far infrared/submillimetre universe. The Spectral and Photometric Imaging REceiver (SPIRE) is one of Herschel's instruments and consists of a three band imaging photometer and a two band imaging spectrometer. Canada is involved in the SPIRE project through provision of instrument development hardware and software, mission flight software, and support personnel. This thesis discusses Fourier transform spectroscopy (FTS) and FTS data processing. A detailed discussion is included on FTS phase correction, with results presented from the optimization of an enhanced Forman phase correction routine developed for this work. This thesis discusses the design, verification, and use of the hardware and software provided by Dr. Naylor's group as it relates to SPIRE verification testing. Results of the photometer characterization are presented. The current status of SPIRE and its future schedule is also discussed. / xvii, 239 leaves : ill. (some col.) ; 28 cm.

Šiame darbe analizuojama šviesos įtaka regos procesui. Išnagrinėta mokslinė literatūra žmogaus regos, ryškumo, kontrasto ir spalvų suvokimo bei regos aštrumo klausimais. Išanalizuoti žmogaus regos proceso ypatumai, regos fiziologija. Pristatomi pagrindiniai fotometriniai dydžiai bei jų sąsaja su regos sistema. Atliktas tyrimas, kurio metu nustatoma regos aštrumo priklausomybė nuo paviršiaus apšvietos. Tyrime dalyvavo 50 žmonių. Tiriamieji suskirstyti į dvi: 40-50 ir 51-60 metų amžiaus grupes. Tyrime nustatyta, tiriamųjų regos aštrumo priklausomybė nuo įvairių apšvietų, apskaičiuoti vidutiniai tyrimo duomenų rezultatai, pateikta, tyrimo eigoje išryškėjusi adaptacijos tamsai įtaka. Šie tyrimo duomenys pavaizduoti grafiškai. Analizuojant teorinę medžiagą pastebėta, kad Lietuvoje, tai mažai tyrinėta sritis. Gauti tyrimo rezultatai rodo, kad padarius didesnius, daug daugiau tiriamųjų, kriterijų, apimančius tyrimus, būtų galima gauti įdomių rezultatų. / The subject of the work is the investigation of the visual acuity dependence on surface illumination. This final work analyzes the influence of light to visual process. Scientific literature was studied to look into the issues of human’s eyesight, brightness, contrast and color perception and visual acuity. The features of the human visual process and physiology of human’s eyesight have been examined as well. The work introduces the main photometric values and their relation to the visual system. The investigation has been carried out to determine the dependence of visual acuity on the surface illumination with 50 people participating in it. The people were divided into two groups according to their age: 40-50 and 51-50. The average data of the results have been estimated and various deviations from the mean shown up during the investigation are graphically presented in the work. While studying the theoretical material it was noticed that this field is still a byway in Lithuania. The findings suggest that if deeper and more criteria spanning researches were carried out, more revealing results could be expected.