Image Processing Applications in Real Life: 2D Fragmented Image and Document Reassembly and Frequency Division Multiplexed Imaging

In this era of modern technology, image processing is one the most studied disciplines of signal processing and its applications can be found in every aspect of our daily life. In this work three main applications for image processing has been studied. In chapter 1, frequency division multiplexed imaging (FDMI), a novel idea in the field of computational photography, has been introduced. Using FDMI, multiple images are captured simultaneously in a single shot and can later be extracted from the multiplexed image. This is achieved by spatially modulating the images so that they are placed at different locations in the Fourier domain. Finally, a Texas Instruments digital micromirror device (DMD) based implementation of FDMI is presented and results are shown. Chapter 2 discusses the problem of image reassembly which is to restore an image back to its original form from its pieces after it has been fragmented due to different destructive reasons. We propose an efficient algorithm for 2D image fragment reassembly problem based on solving a variation of Longest Common Subsequence (LCS) problem. Our processing pipeline has three steps. First, the boundary of each fragment is extracted automatically; second, a novel boundary matching is performed by solving LCS to identify the best possible adjacency relationship among image fragment pairs; finally, a multi-piece global alignment is used to filter out incorrect pairwise matches and compose the final image. We perform experiments on complicated image fragment datasets and compare our results with existing methods to show the improved efficiency and robustness of our method. The problem of reassembling a hand-torn or machine-shredded document back to its original form is another useful version of the image reassembly problem. Reassembling a shredded document is different from reassembling an ordinary image because the geometric shape of fragments do not carry a lot of valuable information if the document has been machine-shredded rather than hand-torn. On the other hand, matching words and context can be used as an additional tool to help improve the task of reassembly. In the final chapter, document reassembly problem has been addressed through solving a graph optimization problem

Microscale Chemical Manipulation and Imaging Using Photoactive Molecules and Light

Chemical manipulation with light has been an active and growing area of research with important implications in materials science, biotechnology, and environmental science. From early investigations of light sensitive materials for photography in the 19th century, to printing billions of transistors on a semiconductor chip in present day, scientists have gained a deep understanding of photochemistry and the processes that allow us to harness light for everyday applications. In this work, we explore microscale fabrication and molecular imaging using light and photoactive molecules as foundational tools. We develop a visible-light mediated technique for high resolution microscale chemical lithography comprising of a home-built digital light processing fluorescence microscope, optimized photochemical reactions, and light responsive molecules. We leverage the ability to control, structure, and build with visible light at a microscale to fabricate self-propelling catalytic micromotors based on existing and novel catalytic systems, and characterize their performance. To further the horizons of light-mediated chemistries to cutting-edge single molecular resolutions, we introduce chemical systems with paired fluorescence and reactivity, which in conjunction with super resolution imaging will allow for chemical lithography with unprecedented specificity. Finally, we design and apply near-infrared light emitting molecular systems for chemiluminescent imaging from within biological tissue, furthering advancement of non-invasive methods for molecular biosensing and quantification. Altogether, these works demonstrate the versatility and growing applications of visible light for microscopic chemical manipulation and imaging when combined with tailored photoactive molecules

ipProjector: Designs and Techniques for Geometry-Based Interactive Applications Using a Portable Projector

We propose an interactive projection system for a virtual studio setup using a single self-contained and portable projection device. The system is named ipProjector, which stands for Interactive Portable Projector. Projection allows special effects of a virtual studio to be seen by live audiences in real time. The portable device supports 360-degree shooting and projecting angles and is easy to be integrated with an existing studio setup. We focus on two fundamental requirements of the system and their implementations. First, nonintrusive projection is performed to ensure that the special effect projections and the environment analysis (for locating the target actors or objects) can be performed simultaneously in real time. Our approach uses Digital Light Processing technology, color wheel analysis, and nearest-neighbor search algorithm. Second, a paired projector-camera system is geometrically calibrated with two alternative setups. The first uses a motion sensor for real-time geometric calibration, and the second uses a beam splitter for scene-independent geometric calibration. Based on a small-scale laboratory setting, experiments were conducted to evaluate the geometric accuracy of the proposed approaches, and an application was built to demonstrate the proposed ipProjector concept. Techniques of special effect rendering are not concerned in this paper

An investigation into the history of the airbrush and the impact of the conservation treatment of airbrushed canvas paintings

The research considers whether traditional approaches to easel paintings conservation are appropriate for the treatment of air brush paintings. The objectives were: -To investigate the aesthetic and technical history of the airbrush -To investigate surface changes in paint layers -To investigate the appropriateness of traditional conservation treatments for airbrush paintings and evaluate alternative approaches Although the first airbrush was introduced in 1883 it was initially rejected by many fine art circles as being too ‘mechanical’. Airbrush techniques have been little discussed in the field of fine art and the field of the conservation of fine art. A mixed methodology was followed for this research, qualitative through literature review carried out in line with the interdisciplinary nature of the research, and quantitative through various approaches including surveys. One survey was carried out in order to establish the use of air brush techniques by artists and its eventual acceptance as a fine art technique. A second survey was conducted to discover how well conservators understood the degradation characteristics of air brush paintings and their appropriate treatment. The research revealed that much of the eventual success of air brush painting resulted from the introduction of new types of paint in order to better manage the technique. It also revealed that there was a high level of uncertainty amongst practitioners in the field of paintings conservation with regard to the deterioration characteristics of air brush painting or their appropriate resolution. However the major concern with regard to conservation lay clearly within the field of image re-integration as a result of its characteristically smooth surface finish. Artificial light ageing was carried out on simulated mock ups in order to develop a clearer understanding of the type of surface changes that might be expected over time from a limited palette of colours. This was followed by technical visual examination and media analysis via FTIR and Py- GC-MS methods. It was found that there were changes in surface morphology in some colours, which appeared to further enhance the smooth surface finish of the paint layer. A range of approaches to image re-integration were trialled ranging from the traditional paint based approaches to the use of digital coloured light. The latter was of particular interest in offering a truly reversible none interventive approach to re-integration. The focus of the digital re-integration techniques was to evaluate the viability of its use in general practice. Due to the smooth surface as well as the build-up of multiple layers of colour the traditional approaches proved difficult to harmonise within the picture plain. The use of digital approaches using coloured light was more successful although further research is required in order to develop this approach for wide spread professional practice. The physical and chemical characteristics of the airbrushed paint layer present issues that are fundamentally different to those found in oil paintings. As yet these are not all fully understood and require further research. Until such time the use of none interventive, reversible image re-integration techniques such as coloured light would be recommended

Comparing of radial and tangencial geometric for cylindric panorama

Cameras generally have a field of view only large enough to capture a portion of their surroundings. The goal of immersion is to replace many of your senses with virtual ones, so that the virtual environment will feel as real as possible. Panoramic cameras are used to capture the entire 360°view, also known as panoramic images.Virtual reality makes use of these panoramic images to provide a more immersive experience compared to seeing images on a 2D screen. This thesis, which is in the field of Computer vision, focuses on establishing a multi-camera geometry to generate a cylindrical panorama image and successfully implementing it with the cheapest cameras possible. The specific goal of this project is to propose the cameras geometry which will decrease artifact problems related to parallax in the panorama image. We present a new approach of cylindrical panoramic images from multiple cameras which its setup has cameras placed evenly around a circle. Instead of looking outward, which is the traditional ”radial” configuration, we propose to make the optical axes tangent to the camera circle, a ”tangential” configuration. Beside an analysis and comparison of radial and tangential geometries, we provide an experimental setup with real panoramas obtained in realistic conditionsLes caméras ont généralement un champ de vision à peine assez grand pour capturer partie de leur environnement. L’objectif de l’immersion est de remplacer virtuellement un grand nombre de sens, de sorte que l’environnement virtuel soit perçu comme le plus réel possible. Une caméra panoramique est utilisée pour capturer l’ensemble d’une vue 360°, également connue sous le nom d’image panoramique. La réalité virtuelle fait usage de ces images panoramiques pour fournir une expérience plus immersive par rapport aux images sur un écran 2D. Cette thèse, qui est dans le domaine de la vision par ordinateur, s’intéresse à la création d’une géométrie multi-caméras pour générer une image cylindrique panoramique et vise une mise en œuvre avec les caméras moins chères possibles. L’objectif spécifique de ce projet est de proposer une géométrie de caméra qui va diminuer au maximum les problèmes d’artefacts liés au parallaxe présent dans l’image panoramique. Nous présentons une nouvelle approche de capture des images panoramiques cylindriques à partir de plusieurs caméras disposées uniformément autour d’un cercle. Au lieu de regarder vers l’extérieur, ce qui est la configuration traditionnelle ”radiale”, nous proposons de rendre les axes optiques tangents au cercle des caméras, une configuration ”tangentielle”. Outre une analyse et la comparaison des géométries radiales et tangentielles, nous fournissons un montage expérimental avec de vrais panoramas obtenus dans des conditions réaliste

A study of the expansion of a laser produced lithium plasma using spatially and temporally resolved imaging and spectroscopic techniques

The study of the expansion of a laser produced lithium plasma using spatially and temporally resolved imaging and spectroscopic diagnostic techniques is described. The diagnostic system consists of three separate components: a 2.2m grazing incidence spectrometer (coupled to an Extreme Ultra-Violet (EUV) sensitive photodiode array), a recently developed fast-frame photography apparatus comprising a CCD camera coupled to a gated image intensifier, and a newly developed shadowgraphy apparatus consisting of a combination of a Nd:YAG pumped dye laser and a CCD camera. The development and capabilities of the diagnostic techniques used to characterise the plasma expansion are outlined. Furthermore, the characterisation of new or additional instrumental parameters pertinent to the quantitative interpretation of the experimental data is explored. Using the 2.2m grazing incidence spectrometer, temperature and density profile estimates for a laser produced lithium plasma are inferred. Photoabsorption spectra using this instrument and a newly developed model, for the 1s2 -> 1snp (n = 4,5,6 and 7) in Li+, are synthesised for the first time. Employing the fast-frame photography technique, species velocities and corresponding temperature estimates are obtained. Additionally, excited state density distributions are extracted by application of the Abel transform. Finally, the shadowgraph technique is used to furnish electron density distribution information. In all cases plasma parameters, determined using the diagnostic techniques proposed, are correlated with novel computer codes developed, based on established plasma expansion models. The thesis concludes with a description of future work with an emphasis on prospective extensions to the diagnostic techniques developed

Three-dimensional geometry characterization using structured light fields

Tese de doutoramento. Engenharia Mecânica. Faculdade de Engenharia. Universidade do Porto. 200

Programmable Spectral Source and Design Tool for 3D Imaging Using Complementary Bandpass Filters

An endoscopic illumination system for illuminating a subject for stereoscopic image capture, includes a light source which outputs light; a first complementary multiband bandpass filter (CMBF) and a second CMBF, the first and second CMBFs being situated in first and second light paths, respectively, where the first CMBF and the second CMBF filter the light incident thereupon to output filtered light; and a camera which captures video images of the subject and generates corresponding video information, the camera receiving light reflected from the subject and passing through a pupil CMBF pair and a detection lens. The pupil CMBF includes a first pupil CMBF and a second pupil CMBF, the first pupil CMBF being identical to the first CMBF and the second pupil CMBF being identical to the second CMBF, and the detection lens includes one unpartitioned section that covers both the first pupil CMBF and the second pupil CMBF