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Home > Adaptive Wavelet Thresholding for Non- Homogeneous Noise Reduction in Mr Magnetic Resonance Images

Adaptive Wavelet Thresholding for Non- Homogeneous Noise Reduction in Mr Magnetic Resonance Images

Thesis Info

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Author

Hussain, Rashid

Program

PhD

Institute

Hamdard University

City

Karachi

Province

Sindh

Country

Pakistan

Thesis Completing Year

2011

Thesis Completion Status

Completed

Subject

Commerce

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1799

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676724454783

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Noise suppression in MR (Magnetic Resonance) images is a critical task; conventional signal processing techniques are not always suitable as spatial resolution may lose during noise suppression process. Therefore noise suppression ought to be performed in a manner so as to preserve the actual pattern of the image. Non-homogeneous noise is one of the challenges faced in image processing. This thesis work; specifically focuses on non-homogeneous noise suppression method for MR images. Wavelet Analysis has widely been used for image processing including image de-noising, edge detection and segmentation. The existing wavelet de-noising methods are focused on homogeneous noise removal, using same threshold for entire image. If the image contains different burst of random noise, these conventional methods are not sufficient for effective noise removal. The quality of the post-processed image is further affected if these noise patterns cover hard to find malignant areas, which possibly increases the false alarm for diagnostic imaging. In order to improve the early detection of possible malignant areas, the quality of the post-processed image requires effective de-noising techniques, which can be adapted with the nature of noise burst. The fuzzy rule based wavelet thresholding method has been explored in this research for effective noise removal from an image with an array of complexities. In order to develop a robust system closer to real image with non-homogeneous noise, a complex range of noise patterns have been incorporated in MR images. The initial phase of the dissertation work involves the synthesis of non-homogeneous noise on various MR images. Real MR images without noise burst were used as a benchmark. The de- noised images are compared with their clean counterparts for measuring the effectiveness of the technique. A novel image synthesis process has been developed for analyzing the image de- noising and segmentation. Some of the images contain various sizes of malignant patterns for full scale analysis of image de-noising and fuzzy image segmentation. The main focus of the analysis is the brain image, as it requires rigorous image assessments for an effective classification and detection of patterns. The second phase of the dissertation work expounds the wavelet thresholding for various sets of images. An in-depth investigation of fuzzy rule based optimizer for adapting the wavelet threshold for effective noise suppression has been examined. In this technique, the threshold is further optimized, based on number of criterion including; the intensity, location and size of the noise burst over the malignant patterns. Therefore the present technique improves the post processing diagnostic of images containing small pattern(s) hidden under noise bursts, which otherwise goes undetected. The third phase of the dissertation work studies the impact of non-homogeneous noise on the performance of fuzzy image clustering algorithm. Various results were analyzed for clean, noisy and de-noised images. The purpose here is to segment the malignant areas of noisy brain MRI for effective tumor detection. Fuzzy rule based optimizer plays an important role for adapting the wavelet threshold for the region of interest. The fuzzy information of image contours and noise burst transformed into crisp control decision signals for adapting the threshold. In addition, it was found that the noisy image with no tumor has a false possibility of detecting benign pattern as malignant area. Other research outcome includes the detection of patterns in an image with invisible noise bursts using Multi-resolution Analysis. The result of this course of action is obtained in the diagonal detail components of multi-level decomposition. The difficulties observed in the prevailing methodology include the limited set of research studies conducted to address the issue of non-homogeneous noise in MR Images and the limited accessibility of real images. A good source of validation is the comparison of the de- noised image with that of clean image. Impact of non-homogeneous noise has been explored using directional wavelet. This analysis demonstrates how adversely, different noise patterns affect the computational performance of curvelets and ridglet. The main outcomes of this technique include the impact of non- homogeneous noise on wavelet and curvelet based de-noising methods. An important attribute of this research, is improved methodology for malignant patterns detection in noisy MR Images. This, in turn, makes possible the better development of image diagnostic tools.
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غزل

 

نہ خط لکھوں نہ زبانی کلام تجھ سے رہے
رہے بس اتنا شناسائی کا بھرم باقی
نہ عہدِ ترکِ تعلق، نہ قربتیں پیہم
یہی رہیں ترے نشتر، ترا طریق علاج
نظر میں عکس فشاں ہو ترے جمال کی دھوپ
اب اس سے بڑھ کے مجھے چاہیے بھی کیا آخر
خاموشیوں کا یہی انتقام تجھ سے رہے
اشارتاً ہی دعا و سلام تجھ سے رہے
بس ایک ربطِ مسلسل، مدام تجھ سے رہے
اسی طرح غمِ دل کو دوام تجھ سے رہے
دیارِ جاں میں سدا رنگِ شام تجھ سے رہے
دیارِ فن میں اگر میرا نام تجھ سے رہے

Financial Misgivings of Married Working Women in Lahore

In Pakistan, the financial issues of married working women are rarely discussed. There is an absence of literature on the subject. Nevertheless, the social sciences literature has been debating financial aspect of gender, either from the perspective of employer or employee; ignoring the working women’s reservations regarding their financial contribution in their marital life, particularly with reference to spouse and in-laws expectations. This issue becomes more acute when it comes to patriarchal conservative developing societies. This study is a delicate attempt to understand the magnitude of financial support of Pakistani married working women for spouse and in-laws, in the city of Lahore. In routine, the husband as well as the in-laws expect that a working wife should surrender her income, in entirety or partially towards the household budget, thus taking the financial responsibility of her spouse along with his extended family. Such financial misgivings create tensions and pressure for the already burdened woman having a disadvantaged status. In certain cases, the contribution is by free will of the wife, as well. This research will make an attempt through a survey with 50 married working women of different social classes, residing in Lahore. The purpose is to understand the rationale of approval or disapproval of this practice. Refusal for cooperation often create problems for the earning woman, even at the risk of separation or divorce, or at the least, tensions in the married life. At the end, the study will debate over possible adjustments and compromises, which could reduce tense situation for the married working woman, and at the same time maintaining her financial independence.

Effect of Diafenthiuron Exposure on the Histology of Selected Vital Organs, Hematology and Serum Biochemical Profile of a Non Target Organism, Labeo Rohita

Diafenthiuron is a thiourea derivative pesticide that is commonly used against sucking pests in Pakistan. Present work was designed to report the toxic effect of diafenthiuron on non-target organism, Labeo rohita behavior, growth, hematology, serum biochemical profile, elemental composition in fish muscles and histology of vital organs. Juvenile freshwater Cyprinid fish Rahu (Labeo rohita) of both sexes (body length 12.5-25.5cm and body weight 27.7 to 163.63g) were purchased (N=500) from Faheem Fish Form Multan. Fish were acclimatized to controlled lab conditions. Fish were exposed to 0.0038, 0.01, 0.05, 0.1 and 0.5 mg L-1 of Diafenthiuron for 96 hours. A pesticide untreated control group was maintained in parallel. Fish mortality was observed after 24h, 48h, 72h and 96 h and 96h Diafenthiuron LC50 value for Labeo rohita was found to be 0.272 mgL-1. Experimental series include short and long term phases. During short term experiments, Labeo rohita were exposed to sublethal concentration of 0.0075 mgL-1 of Diafenthiuron for 2, 4 and 8 days respectively while in long term experiments, fish were exposed to same dose for 16, 32 and 64 days. In parallel control group was maintained for each experimental treatment. The Diafenthiuron treated fish showed avoidence response as it displayed abrupt and sluggish swimming movements with heavy mucous secretion and fish body colour changed to light brown. The pesticide exposed fish had significantly higher white blood cell, lymphocyte and red blood cell count, hemoglobin concentration, hematocrit, mean corpuscular volume, red blood cells distribution width, while platelets count, plateletcrit and platelet distribution were significantly decreased than control group. Similarly, concentration of total serum proteins, albumin, globulin, cholesterol, triglyceride concentrations and asparate aminotransferase were disturbed in different diafenthiuron exposed treatments than their control groups. Analysis of elemental concentration data from fish muscle showed that there were significant variations in calcium, potassium and cadmium concentration when compared between diafenthiuron treated and untreated groups. Wrinkling of cell membrane of hepatocytes, diffused hepatocytes necrosis, dislocation of nucleus, pycnosis of hepatic nuclei and dilation of blood sinusoid were observed in liver of fish exposed to Diafenthiuron. These results are in agreement with our results from complete blood count and serum biochemical analysis that had indicated an infectious state in fish with disturbed metabolism. In Diafenthiuron treated Labeo rohita, a number of vacuolation and swellings in some renal tubular cells, shrinking of glomerulus were observed. The renal tubules exhibited shrunken lumen and vacuolated cytoplasm, pyknosis of nucleus, necrosis of renal tubular epithelial cells occurred, infiltration of leucocyte spread throughout and condensation of epithelial cells of tubules, karyorrhexsis and karyolysis indicated pesticide induced stress affecting the kidney histology severely. In conclusion, we have observed that sublethal dose (0.0075 mgL-1) of Diafenthiuron significantly affected the behavior, blood chemistry, histology of vital organs; elemental concentration in muscles of Labeo rohita than control groups indicating that Diafenthiuron has potential to adversely affect the physiology of non target organism, Labeo rohita. Therefore, we recommend strict measures to be taken at the government and public levels to prevent the entry of pesticides into water bodies to keep our food chains and food webs intact for sustaining life on the earth.