Non-parametric Methods for Automatic Exposure Control, Radiometric Calibration and Dynamic Range Compression

Imaging systems are essential to a wide range of modern day applications. With the continuous advancement in imaging systems, there is an on-going need to adapt and improve the imaging pipeline running inside the imaging systems. In this thesis, methods are presented to improve the imaging pipeline of digital cameras. Here we present three methods to improve important phases of the imaging process, which are (i) ``Automatic exposure adjustment'' (ii) ``Radiometric calibration'' (iii) ''High dynamic range compression''. These contributions touch the initial, intermediate and final stages of imaging pipeline of digital cameras. For exposure control, we propose two methods. The first makes use of CCD-based equations to formulate the exposure control problem. To estimate the exposure time, an initial image was acquired for each wavelength channel to which contrast adjustment techniques were applied. This helps to recover a reference cumulative distribution function of image brightness at each channel. The second method proposed for automatic exposure control is an iterative method applicable for a broad range of imaging systems. It uses spectral sensitivity functions such as the photopic response functions for the generation of a spectral power image of the captured scene. A target image is then generated using the spectral power image by applying histogram equalization. The exposure time is hence calculated iteratively by minimizing the squared difference between target and the current spectral power image. Here we further analyze the method by performing its stability and controllability analysis using a state space representation used in control theory. The applicability of the proposed method for exposure time calculation was shown on real world scenes using cameras with varying architectures. Radiometric calibration is the estimate of the non-linear mapping of the input radiance map to the output brightness values. The radiometric mapping is represented by the camera response function with which the radiance map of the scene is estimated. Our radiometric calibration method employs an L1 cost function by taking advantage of Weisfeld optimization scheme. The proposed calibration works with multiple input images of the scene with varying exposure. It can also perform calibration using a single input with few constraints. The proposed method outperforms, quantitatively and qualitatively, various alternative methods found in the literature of radiometric calibration. Finally, to realistically represent the estimated radiance maps on low dynamic range display (LDR) devices, we propose a method for dynamic range compression. Radiance maps generally have higher dynamic range (HDR) as compared to the widely used display devices. Thus, for display purposes, dynamic range compression is required on HDR images. Our proposed method generates few LDR images from the HDR radiance map by clipping its values at different exposures. Using contrast information of each LDR image generated, the method uses an energy minimization approach to estimate the probability map of each LDR image. These probability maps are then used as label set to form final compressed dynamic range image for the display device. The results of our method were compared qualitatively and quantitatively with those produced by widely cited and professionally used methods

COVID-19 presenting with spontaneous pneumothorax

The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease mainly affects respiratory system. Its common clinical findings include fever, cough and shortness of breath. Characteristic radiological features of the disease include peripherally distributed, bilateral ground-glass opacities, predominantly involving the lower lung zones. In this report, we present a case of COVID-19 disease presenting with spontaneous pneumothorax. A 26-year male patient was admitted to the Emergency Department with fever, dry cough, shortness of breath and right-sided chest pain. Radiographic imaging of the patient revealed pneumothorax on the right and peripherally distributed non-homogenous opacification. The patient underwent right lateral tube thoracostomy. COVID-19 was diagnosed on testing of nasopharyngeal swab. In conclusion, spontaneous pneumothorax is one of the rare presentations of COVID-19 pneumonia and should be kept in mind in patients presenting with shortness of breath and chest pain

Financial Leverage and Its Impact on Profit Margin in Pakistan’s Textile Industry

The core purpose concerned in this study remains to explore the impact of the financial leverage on the stitched textile industry, and mainly on the profit margin. The textile industry in Pakistan is said to be the largest manufacturing industry and so is the stitching industry increasing with the great importance of readymade dresses especially among females. The objective set in this study remains to study the relationship between the Financial Leverage (FL) and the Profit Margin (PM). This further includes the proving of the idea that the stitched industry becomes more profitable as soon as the financial leverage has been adopted by the companies. The data from 10 Stitched-Textile companies has been gathered as a sample in this study, from the period of 2012 to 2015 for data analysis. The tools used for data analysis comprised of descriptive analysis, correlation analysis,and regression analysis. The results from this analysis conclude that in the stitching industry there is no significance recognition but positive impact on the FL by the PM. Therefore, it is being recommended that the best possible use of the FL should be made by the stitched industry in order to achieve the target of becoming the most profitable industry of Pakistan Textile Industry. Furthermore, it could be noted that the optimum increase in the production of the textile industry would help in minimizing the level of poverty in Pakistan and also building a healthy population. Keywords: Financial Leverage; Profit Margin, Stitched-Textile Industry, profitability. DOI: 10.7176/EJBM/11-12-13 Publication date: April 30th 201

Web readability factors affecting users of all ages

With the increase in the growth of internet since 1990 WorldWide Web have gained a worldwide popularity.Web has become an ultimate source of information throughout the world. The web has been a source of information, knowledge, entertainment and carrying out different tasks such as online shopping, reservation etc. Every one finds ways to the web due to easiness of access and the bulk of information that has been available so ways to make web more attractive and easy to interact with has been an issue under discussion since its inception. In this paper we have focused how to make a webpage more usable for different age group in terms of readability. We have focused on eight eternal readability factors i.e. color contrast, white space, line spacing, font style, font size, text width, headings, graphics and animation. These eight factors are compared that how different age group people behave with the web applications by varying these eight factors. Based on literature review we have proposed an idea that how to make web more readable for people of different age groups e.g. children, teenagers and old /senior users

Instant dynamic response measurements for crack monitoring in metallic beams

This paper investigates the interdependencies of the modal behaviour of a cantilever beam, its dynamic response and crack growth. A methodology is proposed that can predict crack growth in a metallic beam using only its dynamic response. Analytical and numerical relationships are formulated between the fundamental mode and crack growth using the existing literature and finite element analysis (FEA) software, respectively. A relationship between the dynamic response and the modal behaviour is formulated empirically. All three relationships are used to predict crack growth and propagation. The load conditions are considered the same in all of the experiments for both model development and model validation. The predicted crack growth is compared with the visual observations. The overall error is within acceptable limits in all comparisons. The results obtained demonstrate the possibility of diagnosing crack growth in metallic beams at any instant within the operational conditions and environment

Primary Infertility from Bilateral Ovarian Hydatid Cysts: A Case Report

Hydatid disease is a parasitic infection. The causative organism is Echinococcus which is a parasitic tapeworm. Its larval stage can survive in various regions of the human body, especially the liver. However, the primary ovarian location is very unusual. In our case, the patient with primary infertility had bilateral ovarian cysts on sonogram which in histopathology were found to be hydatid cysts

An agent based architecture for cognitive spectrum management

In the recent years, wireless technologies and devices have progressed dramatically that has augmented the demand for electromagnetic spectrum. Some research work showed that spectrum access and provision to user is not possible due to shortage of spectrum but federal communication commission refused to accept this theory and indicated that the spectrum is available since most of the frequency bands are underutilized. In order to allow the use of these frequency bands without interference, cognitive radio was proposed that characterizes the growing intelligence of radio systems can adapt to the radio environment, allowing opportunistic usage and sharing with the existing uses of spectrum. To take this concept a step further, we propose to use intelligent agent for spectrum management in the context of cognitive radio in this paper. In our proposed architecture, agents are embedded in the radio devices that coordinate their operations to benefit from network and avoid interference with the primary user. Agents carry a set of modules to gather information about the terminal status and the radio environment and act accordingly to the constraints of the user application

Visualization representation benefits of pre-requirement specification tractability

Representation of Pre-RST information is very useful using visualization elements for realization of benefits of requirements tractability This improves the practitioners motivation to maintain Pre-RST information during life cycle processes. Few researchers proposed visualization for post-RST due to which many benefits of requirements tractability cannot be realized. This paper proposed an important visualization representing Pre-RST information that demonstrate various benefits of requirements tractability. In order to evaluate empirically an experiment is conducted and textual representation of tractability information is obtained. In order to strengthen our claim a survey is conducted to compare textual representation of tractability information with proposed visualization and results are compiled