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Motion Correction in Compressively Sampled Dynamic Mr Imaging

Thesis Info

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Author

Bilal, Muhammad

Supervisor

Jawad Ali Shah

Program

PhD

Institute

International Islamic University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Electronics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/12555/1/Muhammad%20Bilal_Electronics_2019_IIU_PRR.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727792593

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Magnetic Resonance Imaging (MRI) is a non-invasive but slow imaging modality for studying different anatomical and functional aspects of human body. However, it is difficult for a patient to remain motionless during the slow MR acquisition process. The subject motion is one of the main hurdles in MRI due to the fact that the respiratory motion is faster compared to acquisition process resulting in ghosted and blurry recovered images. Cardiac and abdominal MR imaging is mostly affected by respiratory motion. In this thesis, compressive sensing (CS) based new approaches are developed to tackle the respiratory motion in cardiac and abdominal MRI examination. The cost function used by CS based MR recovery algorithms include ?1-norm penalty to exploit the transformed domain sparsity of the acquired MR data. The initial part of dissertation presents a comparison of surrogate functions used to approximate the l1-norm penalty. The experimental work shows that the hyperbolic tangent based function outperforms its competing function in the recovery of static MR images for different acceleration rates and various Gaussian noise levels. Based on these findings, an iterative thresholding algorithm utilizing hyperbolic tangent based ?1-norm approximation is developed to recover free breathing dynamic MR images from sub-sampled k-space data. A block matching algorithm, known as Adaptive Rood Pattern Search (ARPS) is then used to estimate and correct respiratory motion among the recovered images. In the next part, an adaptive thresholding parameter utilizing the MR data statistics is derived and used in wavelet domain shrinkage to recover both static and dynamic MR images. A novel iterative shrinkage thresholding (IST) algorithm based on the derived adaptive parameter is also proposed. Results show that the MR recovery using adaptive threshold is more effective in the presence of motion as compared to fixed threshold value. The final part presents the reduction of motion artifacts in the recovery of under-sampled abdominal and liver dynamic contrast enhanced (DCE) MR images using data binning and low-rank plus sparse (L+S) decomposition. In the data binning, radial k-space data is acquired continuously using golden-angle radial sampling pattern and grouped into various motion states or bins. The respiratory signal for binning is extracted directly from radially acquired k-space data. A compressed sensing (CS)-based L+S matrix decomposition model is then used to reconstruct good quality DCE MR images. The proposed techniques are validated using simulated and clinical MRI data.
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ماہیا

ماہیا

ماہیا سر زمین پنجاب کا عوامی گیت ہے۔ماہیا کا لفظ ماہی سے نکلا ہے لیکن یہ اردو والا ماہی نہیں ہے(1) ویسے ماہیا میں محب اپنے محبوب کی جدائی میں ماہی بے آب کی طرح بھی ترپتا دکھائی دیتا ہے۔پنجابی میں بھینس یا مہیس کو کہتے ہیں۔بھینس چرانے والوں کو اسی نسبت سے ماہی کہا جا تا ہے۔ان چرواہوں کو بھینسوں پر نظر رکھنے کے سوا کوئی کام نہیں ہوتا تھا۔اس لئے دیہاتی ماحول کے مطابق انہوں نے کسی مشغلے کے ذریعے وقت گزاری کا وقت نکلا۔بانسری بجانے اور گیت گانے کا مشغلہ ایسا تھا کہ بیک وقت چرواہے کا فرض بھی ادا کیا جا سکتا تھا اور اپنے دل کو بھی بہلایا جا سکتا تھا۔بانسری اور اچھی آواز کے جادو نے بھی بعض چرواہوں کو اپنے اپنے دیہاتوں میں مقبولیت عطا کی ہوگی لیکن جب محبت کے قصوں میں رانجھے اور مہینوال کو اپنے اپنے محبوب تک رسائی حاصل کر نے کے لیے چرواہ بننا پڑا تو پھر ان کرداروں کی رومانوی کشش نے لفظ ماہی کو چرواہے کی سطح سے اٹھا کر نہ صرف ہیر اور سوہنی کا محبوب بنا دیا بلکہ ہر محبت کرنے والی مٹیار کا محبوب ماہی قرار پایا۔اسی ماہی کے ساتھ اپنے پیار کے اظہار کے لئے ماہیا عوامی گیت بن کے سامنے آیا۔

ماہیے میں پنجاب کے عوام کے جذبات ،احساسات اور خواہشات کا خوبصورت اور براہِ راست اظہار ملتا ہے۔عوام نے اپنی امنگوں ،آرزوں اور دعاوں کو شاعری کے ذریعے سینہ بہ سینہ آگے بڑھایا اور زندہ رکھا۔اسی لیے یہ عوامی گیت اپنی ظاہری صورت میں انفرادی ہونے کے باوجود اپنی سوسائٹی کی ترجمانی کرتا ہے۔ماہیا فکرو خیال سے ہی نہیں ہوتا لیکن گہرے فلسفیانہ خیالات کے برعکس سیدھے عوام کے دل میں اتر جانے والا انداز ہی اس کے مزاج کا...

Sponsoring Academic Integrity: The Role of Human and Informational Sources of Scholarship in Adoption of Plagiarism-Avoiding Techniques among Research Students of Social Sciences

Plagiarism is a serious offense that defies the ethics of scholarship and research. Research students need to pay substantive attention to the dynamics and contours of plagiarism in their creative, ethical, and academic endeavors. Scholarship avenues such as online tutorials and work assignments are important sources of instructions for plagiarism-avoidance among students. The current study explores the frequency of consultation of scholarship avenues and the usage of plagiarism-avoidance techniques among research students in social sciences. The study also recommends a scale to investigate plagiarism-avoidance techniques. Furthermore, it also examines the level of the study in predicting the usage of plagiarism-avoidance. Using the online survey technique, 108 research students from Pakistan were sampled. The questionnaire was uploaded on several student-based research groups of social media, including; Facebook, and Yahoo groups. Bivariate linear regression analysis was used for hypothesis testing. Findings revealed that scholarship avenues lead to greater usage of plagiarism-avoidance techniques among research students (R2 =0.065). Supervisors, class-fellows, colleagues, and faculty of the department are prominent human scholarship avenues. Similarly, articles and books from the web, books from the library, the anti-plagiarism policy of the Higher Education Commission (HEC), and lectures delivered in the classroom were leading informational scholarship avenues. Stage of the study and consultation of the scholarship avenues were predictors of usage of plagiarism-avoidance techniques. It is recommended that (i) plagiarism-avoidance is promoted through prevention rather than detection, and that (ii) scholarship avenues (e.g. Delivering lectures, institutional policy, and interaction with relevant websites) are used for enhancing awareness about intellectual dishonesty.

Linguistic Market Nad Education: Exploring Attitudes of Madrassa Students and Teachers Towards English Language in Khyber Pakhtunkhwa Pakistan

English language is a symbolic capital and an asset in linguistic market. Its contribution in the determination of professional career is considerable. At national level, it can divide or unite a nation. At global level, it has become lingua franca for most of the political, economic, social interactions and working language of international organizations. In Pakistan, it enjoys wide recognition and is a principal means of communication and business. It is also viewed as the language of opportunities. The government takes necessary measures to facilitate its learning in educational institutions yet madrassas lag behind in its implementation contrary to the needs of the professional job market. The purpose of this study was to investigate the teaching situation in madrassas; to probe English language attitudes of madrassa students and teachers; and to look into the possibilities of related reforms in the curriculum. Based on 42 qualitative in-depth interviews conducted in six purposively selected madrassas in the three districts of Khyber Pakhtunkhwa, the findings revealed positive attitudes and willingness to accept the language as part of the curriculum. It was also revealed that the language was not active part of the curriculum owing to the lack of financial resources for provision of books and trained teachers. The study further revealed that the government did not give proper attention to curricular reforms in madrassas. Along with discriminatory attitude of the government, the dominance of conservative anti-western religious elite and the narrow worldview of madrassa authorities alongside poverty and ignorance also contributed to the situation. As part of policy measures, the findings revealed the need for confidence building measures to bridge the gulf between the state’s authorities and religious scholars; attention to the academic requirements of madrassa students; funding for meeting their immediate needs; executive measures to identify, isolate and then target the selected few religious institutions that spread sectarianism and hatred. Further, the government needed to appreciate the socio-educational role of madrassas, to treat them at par with other educational institutions and to enter into a dialogue with reputed scholars at national level for mainstreaming religious education through English language reforms that would provide a fair chance to the graduates in the job market and thus would be a good step forward in bringing madrassas into the mainstream education system.