98 research outputs found
Detail Enhanced Multi-Exposure Image Fusion Based On Edge Preserving Filters
No full textRecent computational photography techniques play a significant role to overcome the limitation of standard digital cameras for handling wide dynamic range of real-world scenes contain brightly and poorly illuminated areas. In many of such techniques [1,2,3], it is often desirable to fuse details from images captured at different exposure settings, while avoiding visual artifacts. One such technique is High Dynamic Range (HDR) imaging that provides a solution to recover radiance maps from photographs taken with conventional imaging equipment. The process of HDR image composition needs the knowledge of exposure times and Camera Response Function (CRF), which is required to linearize the image data before combining Low Dynamic Range (LDR) exposures into HDR image. One of the long-standing challenges in HDR imaging technology is the limited Dynamic Range (DR) of conventional display devices and printing technology. Due to which these devices are unable to reproduce full DR. Although DR can be reduced by using a tone-mapping, but this comes at an unavoidable trade-off with increased computational cost. Therefore, it is desirable to maximize information content of the synthesized scene from a set of multi-exposure images without computing HDR radiance map and tone-mapping.This research attempts to develop a novel detail enhanced multi-exposure image fusion approach based on texture features, which exploits the edge preserving and intra-region smoothing property of nonlinear diffusion filters based on Partial Differential Equations (PDE). With the captured multi-exposure image series, we first decompose images into Base Layers (BLs) and Detail Layers (DLs) to extract sharp details and fine details, respectively. The magnitude of the gradient of the image intensity is utilized to encourage smoothness at homogeneous regions in preference to inhomogeneous regions. In the next step texture features of the BL to generate a decision mask (i.e., local range) have been considered that guide the fusion of BLs in multi-resolution fashion. Finally, well-exposed fused image is obtained that combines fused BL and the DL at each scale across all the input exposures. The combination of edge-preserving filters with Laplacian pyramid is shown to lead to texture detail enhancement in the fused image.Furthermore, Non-linear adaptive filter is employed for BL and DL decomposition that has better response near strong edges. The texture details are then added to the fused BL to reconstruct a detail enhanced LDR version of the image. This leads to an increased robustness of the texture details while at the same time avoiding gradient reversal artifacts near strong edges that may appear in fused image after DL enhancement.Finally, we propose a novel technique for exposure fusion in which Weighted Least Squares (WLS) optimization framework is utilized for weight map refinement of BLs and DLs, which lead to a new simple weighted average fusion framework. Computationally simple texture features (i.e. DL) and color saturation measure are preferred for quickly generating weight maps to control the contribution from an input set of multi-exposure images. Instead of employing intermediate HDR reconstruction and tone-mapping steps, well-exposed fused image is generated for displaying on conventional display devices. Simulation results are compared with a number of existing single resolution and multi-resolution techniques to show the benefits of the proposed scheme for the variety of cases. Moreover, the approaches proposed in this thesis are effective for blending flash and no-flash image pair, and multi-focus images, that is, input images photographed with and without flash, and images focused on different targets, respectively. A further advantage of the present technique is that it is well suited for detail enhancement in the fused image
To study the role of TNF inhibitor in altering apoptosis of matrix producing cells during repair of bacteria induced injury in diabetic mice
No full textPLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please log in with a valid BU account to access and click Download. If you are the author of this work and would like to make it publicly available, please contact [email protected] (MSD)--Boston University Goldman School of Dental Medicine, 2007 (Department of Periodontology and Oral Biology).Includes bibliographical references: leaves 59-68.Diabetics suffer increased infection followed by increased apoptosis of fibroblasts and bone-lining cells during the healing process. To investigate a potential mechanism, we inoculated Porphyromonas gingivalis into the scalp of type 2 diabetic (db/db) or control mice and inhibited tumor necrosis factor (TNF) with etanercept. Mice were euthanized at the early phase of infection (21 hours) or during the peak repair of the bacteria-induced wound (8 days). At 21 hours, TNF inhibition significantly reduced fibroblast apoptosis and caspase-3 activity in both diabetic and normoglycemic mice ([less than] 0.05).During healing etanercept reduced fibroblast apoptosis and caspase-3 activity by almost 50% in diabetic but not normoglycemic mice ([less than] 0.05). Concomitantly, etanercept significantly increased fibroblast number by 31% and new matrix formation by 72% in diabetic mice. When bone was examined during healing, administration of the TNF blocker reduced apoptosis of bone-lining cells by 53%, increased their number by 48%, and enhanced new bone formation by 140% in the diabetic group. The degree of connective tissue and osseous healing stimulated in the diabetic mice by anti-TNF treatment was within the range that is physiologically relevant. This enhanced healing may in part be explained by blocking TNF induced apoptosis of critical matrix-producing cells
Radio Absorbing Material for Next-Generation Wireless Devices
No full textElectrical and computer circuits are particularly susceptible to interference from a wide range of human or natural factors. Interference can occur as noise on communication equipment, flashing over televisions and computer monitors, errors in instrumentation, computer network compatibility problems, and electronic malfunctions. Material absorption and safety serve as a shield to prevent the intrusion of the radio wave from getting through critical components and ensure that electrical circuits perform as planned. Since radio frequency interference can also contribute to damage to infrastructure, proper safety and absorption can greatly increase the service life of electrical and electronic equipment. This paper presents a holistic view of the basic concepts of electromagnetic analysis and developments in radio absorbing materials
DEVELOPMENT AND TESTING OF INTUMESCENT FIRE RETARDANT COATING ON VARIOUS STRUCTURAL GEOMETRIES
No full textMaterials are very prone to catching fire regardless of its type. Once it catches fire, it will take certain amount of time to wipe it off depending on the rate of burning. A small fire will take less time to be cleared where by a big burn out will take a couple of hours to wipe it out. Buildings nowadays can be prone of catching fire and its build on various structural geometries. As it is, Traditional fire retardants are not very effective especially when there is a huge breakout of fires in plants and platforms. These traditional fire retardants also contain halogen and releases toxic vapours thus leading to a severe threat to life and environment. By contrast, intumescent coatings are relatively thin-film products that expand rapidly in a fire to insulate the steel. They come in various formulas that include a mixture of binders and acids that react under temperature to expand up to many times the original thickness of the film, creating a char that insulates the steel. In general, steel loses half its strength at 1,100 °F and begins to degrade as well as starts to loose its properties. Consequently leads us to the aim of this project which is to study the details of the expansion of char and heat shielding performance on various structural geometries with respect to inorganic fillers, (Aluminium Tri-Hydrate) and without filler. Researcher will develop an intumescent coating formulation with inorganic fillers and with no filler in order to get the comparison of optimal performance for char expansion and heat shielding performance on the various structural geometries. In order to meet these challenges, IFRC will be developed and tested on geometries such as T-joints, Elbows, I-Beams and Pipes. The development of coating will consist of three agents mainly Acid Source (APP, Polyphosphate), Carbon Source (EG, Expandable Graphite) and blowing agent (MEL, Melamin) followed by Epoxy, Boric Acid, Polyamide Hardner, etc. Once this coating is mixed, it will then be applied on the various structural geometries. This coating will then be tested in furnace and fire (Bunsen burner). The char expansion as well as heat shielding will be thoroughly observed and results will be obtained and further studied
Therapeutic Potential of Targeting the HMGB1/RAGE Axis in Inflammatory Diseases
No full textHigh mobility group box 1 (HMGB1) is a nuclear protein that can interact with a receptor for advanced glycation end-products (RAGE; a multi-ligand immunoglobulin receptor) and mediates the inflammatory pathways that lead to various pathological conditions, such as cancer, diabetes, neurodegenerative disorders, and cardiovascular diseases. Blocking the HMGB1/RAGE axis could be an effective therapeutic approach to treat these inflammatory conditions, which has been successfully employed by various research groups recently. In this article, we critically review the structural insights and functional mechanism of HMGB1 and RAGE to mediate inflammatory processes. More importantly, current perspectives of recent therapeutic approaches utilized to inhibit the communication between HMGB1 and RAGE using small molecules are also summarized along with their clinical progression to treat various inflammatory disorders. Encouraging results are reported by investigators focusing on HMGB1/RAGE signaling leading to the identification of compounds that could be useful in further clinical studies. We highlight the current gaps in our knowledge and future directions for the therapeutic potential of targeting key molecules in HMGB1/RAGE signaling in the pathophysiology of inflammatory diseases
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