Literature 4u6r32

CHAPTER II REVIEW OF RELATED LITERATURE AND STUDIES This chapter presents the survey of related literature and studies that provide the researchers' knowledge and background of the study. Related Literature According to Abramowitz and Davidson (1999), microscopes are instruments designed to produce magnified visual or photographic images of small objects. The microscope must accomplish three tasks: produce a magnified image of the specimen, separate the details in the image, and render the details visible to the human eye or camera. This group of instruments includes not only multiple-lens designs with objectives and condensers but also very simple single lens devices that are often hand-held, such as a magnifying glass. Dendere et. al. (2015), emphasized that the expansion in global cellphone network coverage coupled with advances in cellphone imaging capabilities present an opportunity for the advancement of cellphone microscopy as a low-cost alternative to conventional microscopy for disease detection in resource-limited regions. The development of cellphone microscopy has also benefitted from the availability of low-cost miniature microscope components such as low-power light-emitting diodes and ball lenses. As a result, researchers are developing hardware and software techniques that would enable such microscopes to produce high-resolution, diagnostic-quality images. This approach may lead to more widespread delivery of diagnostic services in resource-limited areas where there is a shortage of the skilled labor required for conventional microscopy and

where the prevalence of infectious and other diseases is still high. In this paper, we review current techniques, clinical applications and challenges faced in the field of cellphone microscopy. In accordance with the previous statements, Coté and Pirnstill (2015) stated that there is a high fidelity and high optical resolution cell-phone based polarized light microscopy system is presented which is comparable to larger bench-top polarized microscopy systems but at much lower cost and complexity. The detection of malaria in fixed and stained blood smears is presented using both, a conventional polarized microscope and our cell-phone based system. The cell-phone based polarimetric microscopy design shows the potential to have both the resolution and specificity to detect malaria in a low-cost, easy-to-use, modular platform. According to the article made by Kisliuk (2013), a professor of electrical engineering and bioengineering at the UCLA Henry Samueli School of Engineering and Applied Science named Aydogan Ozcan, and his team have created a portable smartphone attachment that can be used to perform sophisticated field testing to detect viruses and bacteria without the need for bulky and expensive microscopes and lab equipment. The device weighs less than half a pound. On the other hand, Skandarajah et. al. (2014) focused on microscopic optical imaging using a custom mobile phone microscope that is compatible with phones from multiple manufacturers. They used all versions of the iPhone and a selection of Android phones released between 2007 and 2012 and showed that phones with greater than 5 MP are capable of nearly diffraction-limited resolution over a broad range of magnifications. By accommodating the differences between mobile phone cameras and the scientific

cameras, mobile phone microscopes can be reliably used to increase access to quantitative imaging for a variety of medical and scientific applications. Overall, the stated literature s that smartphones could be developed as an optical instrument using lens. Tiny things like microorganisms cannot be seen by naked eye so the researchers conducted this study to determine if using smartphones is a good optical instrument.