180 research outputs found
Natural image matting with non-negative matrix factorization
No full textThis report summaries the work done by the author on his Final Year Project at
Nanyang Technological University (NTU) under Associate Professor Deepu Rajan.
The author was involved in implementing an effective way to realize image matting
using Non – Negative Matrix Factorization.
The report provides an overview of the project. It aims to provide the reader an
insight into the author’s role in the development of the matting algorithm. The report
explains the salient features of matting, Non-Negative Matrix Factorization and how
the entire development process was done. The report summarizes the results found
and compares the obtained results with other known algorithms with the use of
images.
It also highlights the domain knowledge, skills gained to accomplish these tasks and
the challenges faced in the process and how they were overcome. The technical
knowledge gained at NTU, was utilized in various ways to fulfill the requirements of
the project.Bachelor of Engineering (Computer Engineering
Microtron Irradiation Induced Tuning of Band Gap and Photoresponse of Al-ZnO Thin Films Synthesized by mSILAR
No full textAl-doped polycrystalline nano ZnO (Al-ZnO) thin films with different doping concentrations were successfully prepared by the microwave-assisted successive ionic layer adsorption and reaction (mSILAR) technique. The structural analysis along with the orientation of the prepared films was examined by powder x-ray diffraction (PXRD) patterns. The deposited film is polycrystalline and the (002) orientation enhanced upon doping. Additional investigations were carried out to study the effect of electron beam irradiation (e−-irradiation) on the band gap and photoconductivity of both irradiated and unirradiated samples. Both the Al doping and e−-irradiation led to the enhancement of the photoconductivity of prepared materials. This property enables us to tune the properties of materials for various applications by controlling dopant concentrations and e−-irradiation. The dependence of photocurrent on e−-irradiation of Al-ZnO thin films was not reported previously. Therefore, Al-doped polycrystalline nano-ZnO thin film is a promising material for band gap engineering and for the development of solar cells
Unconstrained Character Classification For Off-Line Handwritten Devanagari Script Using Multi-Class Model For SVM
No full textInfluence of metal nanoparticles on the light emission properties of rare-earth ions
No full textThe optical properties of metal nanoparticles (MNPs) can differ significantly from those of bulk material. Light can excite a collective oscillation of conduction electrons inside an MNP, thus creating a particle plasmon polariton in the MNP. At the resonance frequencies of the particle plasmon polaritons, the MNP absorbs and scatters light strongly, and the local field near the surface of the MNP changes more drastically as compared to other frequencies. When an oscillating electric or magnetic dipole emitter is placed in the vicinity of the nanoparticle, which acts as an optical nanoantenna, the radiative and non-radiative decay rates of the emitter can be modified due to the coupling between the particle plasmon of the MNP and the dipole emitter. The main focus of this thesis work is to study and understand the modification of the excitation and emission rates of the dipole emitters due to the changes in the local fields in the emitter’s surroundings introduced by metal nanoparticles with various shapes and sizes. The particle plasmon polariton properties of a metal nanoparticle can be utilized for the luminescence rate enhancement of the trivalent rare-earth ions, which can be incorporated into Si solar cells for the enhancement of their overall light-to-current conversion efficiency. At the beginning of this thesis work, the spatial consequences of various metal nanoparticles on radiative (γR) and non-radiative (γNR) decay rates of electric dipole (ED) and magnetic dipole (MD) emitters are investigated. For example, in the extreme nearfield region (d ≤10 nm) of a silver nanosphere, γNR of the ED and MD is observed to vary with 1/d3 and 1/d, respectively, where d is the distance between the dipole emitter and the surface of the silver nanosphere. Numerical results presented in this thesis show that the electric dipole transitions are quenched more strongly than the magnetic dipole transitions at extremely short distances from a metal nanoparticle surface. Furthermore, it is learned from the presented simulation results that when the dipole emitters can couple to a metallic nanoparticle with both electric and magnetic resonances, the electric dipole transitions are still quenched more than the magnetic dipole transitions at extremely close distance to the nanoparticle surface. In the next step, the effects of various MNPs on the photoluminescence emission rate of Sm3+ ions are studied by investigating the effects of the metal nanoparticles with various shapes and sizes on both the excitation and emission decay rates of the Sm3+ ion. The presented calculation results using the finite-element method show that it is more efficient to use nanoparticles made of aluminum than a noble metal for the implementation of rare-earth ions like Sm3+ (doped in a photoluminescence layer) in devices such as photovoltaic solar cells. The physical dimensions such as shape and size of the aluminum nanoparticle can be further modified to obtain an even more suiting aluminum nanoparticle for an experimentally feasible sample configuration with Sm3+ ions. Finally, the influence of gold nanoparticles of various shapes and sizes on the upconversion luminescence emission rate of Er3+ ions are presented and discussed. The presented results in this thesis work are the outcome of various numerical methods. The overall upconversion luminescence enhancement due to a large gold nanosphere (diameters = 300 nm) is compared quantitatively with the results from literature for smaller gold nanospheres (diameters: 100 nm, 140nm and 200 nm). A maximum overall enhancement of around 5% in the volume averaged upconversion luminescence is observed for the largest gold nanosphere with diameter 300 nm. There are almost no enhancements in the volume averaged upconversion luminescence observed for the smaller gold nanospheres discussed in this thesis work. In comparison to the maximum of only 5% in the volume averaged upconversion luminescence enhancement due to the large gold nanosphere, a maximum of around 33% is observed due to the gold nanodisk with length 300nm and height 25 nm. From the presented analysis, it is observed that a metal nanoparticle with large scattering efficiency at both the excitation and emission frequencies of the Er3+ion seems to be the most suitable for the enhancement of the upconversion luminescence rate. Furthermore, it is also observed that it is even more important for a metal nanoparticle to have a large scattering efficiency at the absorption frequency than at the emission frequency of the Er3+ ion in order to achieve a large upconversion luminescence rate enhancement
Distinguishing amateur and professional photographs
No full textPhotography is the art of capturing and handling images. There are many ways to define the aesthetics in photography. The act of quantifying these aesthetic properties directly to distinguish photographs taken by amateur and professional photographers is almost impossible. This is because there is no general consensus. As such, it is beneficial to develop an algorithm that can differentiate the photographs.
In today’s technological advanced society, there are several researches done by computer scientist and engineers specialised in the field of image processing to learn aesthetic properties of the photographs. The properties are changed into computable image features for classification of photographs.
The project requires the author to understand and implement one of the research papers. The author furthers his reach by deriving new features he discovered upon learning more about photography. This allowed him to improve on the classification accuracy.
In this report, the author explains the various aesthetic appeals of photographs that are used for photograph classifications. The concept of computer vision and image processing to use to extract these aesthetic properties in order to convert into computable data and the concept of machine learning to train a model which is used to differentiate photographs are studied in order to fulfil this project’s requirement.
To determine the feasibility of the improved design, an application is implemented on MATLAB platform. It automatically takes in thousands of already classified photographs taken by professional and amateur photographer as training datasets and another set of randomly chosen picture as testing datasets. The program, once executed, allows the author to differentiate the photographs. The main features, design methodology and test specification of the application are discussed in this report.
Performances analysis of the implemented application is noted. The author also identified further areas that can be enhanced.Bachelor of Engineering (Computer Engineering
Studies on Evaluation of Suitability of Mango Varieties Sindura, Mallika and Totapuri for Processing into Canned Products and Development of Blended Ready to Serve Beverages
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Image registration : algorithms and applications
No full textImage registration is the task of determining positions of corresponding points in two images. A fast and accurate image registration plays an important role in many computer vision and graphics problems. This thesis presents fast and robust pixel and feature-based image registration algorithms and explores new applications in computer vision and graphics. It is divided into two parts. In the first part, we propose a fast and accurate pixel-based image registration algorithm that registers a pair of stereo images to extract the three-dimensional information of the scene. The algorithm finds an appropriate match for each reference image pixel in the target image to compute dense depth maps and works very well in case of repetitive patterns, object boundaries, as well as in occluded and non-textured image regions without increasing computational overhead significantly. The three-dimensional information obtained using pixel-based registration is then used to recognize complex human activities. A sequence of depth maps is represented as a sequence of codewords that are learnt to discriminate between activities. These discriminative sub-sequences are then used to classify and localize an activity in a given test video. To demonstrate the efficiency of these algorithms, we provide experimental results on standard datasets which are publicly available. In the second part, we present a feature-based registration method that registers different image features to find most similar images from very large-scale image datasets. The proposed system retrieves and ranks database images based on their similarity to any given input image. By registering different image features, the retrieval and indexing of the relevant images is improved. We use these similar images to solve an ill-posed computer graphics problem, viz., colorization of grayscale images. The algorithm uses similar color images as the reference images and transfers color information to a given input grayscale image using a graph-based optimization method. The algorithm works at the resolution of superpixels and uses local properties for proper color transfer. Our use of superpixels reduces the complexity of our algorithm significantly and it also empowers the colorizations to exhibit a much higher extent of spatial consistency in the colorization as compared to those using independent pixels. We evaluate these approaches on a wide variety of images. Both qualitative and quantitative analyses have been used to demonstrate the greater effectiveness of the proposed approaches.DOCTOR OF PHILOSOPHY (SCE
Effects of experimental fires on litter decomposition in a seasonally dry Amazonian forest.
No full textLitter decomposition is a fundamental process for nutrient cycling but we have a limited understanding of this process in disturbed tropical forests. We studied litter decomposition over a 10-mo period in a seasonally dry Amazon forest in Mato Grosso, Brazil. The study plots (50 ha each) included unburned forest (UF), once-burned (BF1) and forest burned annually for 3 y (BF3). We measured understorey density, litter depth, canopy openness, temperature and relative humidity in the plots. Decomposition experiments took place using 720 litterbags filled with approximately 10 g of natural abscised oven-dried leaves. To test the effects of fire on soil meso- and macrofauna, the litterbags had either a fine (2 mm) or coarse (with 1-cm holes in side) mesh size. Litterbags were collected and reweighed 2, 4, 6 and 8 mo after being placed on the forest floor. All forest structure variables were significantly different across plots: BF3 was hotter, less humid, had the highest degree of canopy openness, lowest understorey density and the shallowest litter depth. Litter decomposition (mass loss) was similar in the once-burned and unburned plots, but declined more slowly in BF3. In addition, decomposition was slower in fine-mesh litterbags than coarse-mesh litterbags in BF3, but there was no difference between mesh sizes in BF1 and UF. It is likely that changes in forest structure and microclimate explain the lower decomposition rates in BF3. These results show the importance of recurrent fires, but suggest that single understorey fires may not have long-term negative effects on some ecological processes in seasonally dry Amazonian forests
Rare Strain of Vibrio cholerae Septicemia in a Patient with Multiple Myeloma
No full textIntroduction. Non-O1/non-O139 is a rare strain of Vibrio cholera that has been documented to cause significant morbidity and mortality in the immunosuppressed population. Case Presentation. A patient with multiple myeloma develops non-O1/non-O139 Vibrio cholera septicemia, leading to multiorgan failure and ultimately death. Discussion. An exceedingly rare strain of Vibrio cholera, non-O1/non-O139, may be an important factor of morbidity and mortality in certain immunosuppressed populations, such as patients with multiple myeloma and malignancies. Conclusion. Bacteremia involving generally noninvasive microbes, such as non-O1/non-O139 Vibrio cholerae, can have significant deleterious effects in the immunosuppressed patients as shown by this case report. Physicians need to be more diligent when treating these patients
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