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Optimal Restoration of Spatially Variant Degraded Images Using Intelligent Methods

Thesis Info

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Author

Bilal, Mohsin

Program

PhD

Institute

National University of Computer and Emerging Sciences

City

Islamabad

Province

Islamabad

Country

Pakistan

Thesis Completing Year

2016

Thesis Completion Status

Completed

Subject

Computer Science

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/9854/1/mohsin.bilal.phd.thesis.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727803721

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Image restoration is fundamental to visual information processing systems. In many real world scenarios, noise and blur are the two main unavoidable sources of degra- dation in images. The problem is deemed as an ill-posed inverse by nature due to the simultaneous occurrences of noise and blur in the image. Blurring function categorizes the degradation as space variant (SVD) if di erent spatial locations of the recorded scene are convolved by varying point spread function. In contrast, the degradation is categorized as spatially invariant (SID) if a unique point spread function blurs the whole image. This dissertation focuses on spatial degradations, initiating from space invariant towards space variant. Existing methods for restoration of SVD images, for example, neural networks and numerical optimization bear the limitations of high cost, lower restoration, less gen- eralization, discontinuity and instability for di erent spatial locations. It is learnt that three factors are vital to develop an e ective framework for restoration, which are: 1. The optimization of the ill-posed inverse restoration problem by minimizing constrained error function 2. A smoothness constraint 3. A regularization scheme The main objective of this dissertation is to improve the restoration results, by possible applications of new intelligent methods. This dissertation provides com- prehensive solutions to both spatial degradation problems, by considering above three factors. Firstly, SID images are restored, by a steepest descent based restora- tion approach. In this approach, an e cient smoothness constraint is proposed, to model the error function. In the next step, the steepest descent based approach is improved and a novel fuzzy regularization scheme is also proposed to better model the error function. It performed better than the existing methods on a speci c blur function and low power additive noise. However, local search properties of gradient based approaches and eventually lower restoration for SVD images, due to their high sensitivity for varying textures, noise powers and blurs allowed for the possible application of computational intelligence models. Finally, in this dissertation, a new optimization framework is proposed for image restoration of SVD images. In the proposed framework, particle swarm optimiza- tion based evolution is retained to minimize the Modi ed Error Estimate (MEE), for better restoration. The framework added hyper-heuristic layer to combine local and global search properties. Therefore, randomness in the evolution, augmented with apriori knowledge from problem domain, assisted in achieving the objective of better restoration. It introduced new swarm initialization and mutation of global best particle of the swarm. In addition, an adaptive weighted regularization scheme is introduced in MEE to cater with the uncertainty due to ill-posed nature of the in- verse problem. Furthermore, a new fuzzy logic and mathematical morphology based regularization scheme is also proposed in the framework, to improve the restoration stability and generalization, for SVD images. Di erent experiments are performed to observe the performance of proposed solu- tions. Visual and quantitative results are obtained and provided for each experiment. Signal-to-noise ratio (SNR) and mean-squared-error (MSE) are computed for com- parative analysis, which endorsed better restoration quantitatively, over well-known restoration methods. However, the stability in restoration performance of proposed framework is observed in visual results, for SVD images. Detailed experimental and comparative analysis shown better restoration, stabilization and generalization of the proposed framework for varied textures in standard and simulated images, and noises over well-known restoration approaches.
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۔غزل

غزل ---ثمینہ سید

کل کے سکھ تو گروی رکھے, پچھلے بوجھ اتارے
جانتی ہوں میں تیز ہوا ہے راہ میں رستہ روکے
ایسے لگتا ہے میں خود ہی اس پہ جھولنا چاہوں
اسی لیے تو نیند کی دیوی سے میں چھپنا چاہوں
دیکھ دیکھ کے ان کو حوصلہ ملتا تو ہے مجھ کو
ایک اداسی کے دھاگے میں خود ہی بندھتی جاؤں
درد کے پیکر میں ڈھل جاتے ہیں معلوم نہیں

 

اندر اندر سلگوں لیکن نکلوں زلف سنوارے
کون  ہے ,خوشبو کے لہجے میں جا کر اسے پکارے
مجھ کو درد کی سولی سے اب آکے کون اتارے
روز مری آنکھوں سے کوئی آگ سے خواب گزارے
میری طرح سے جاگتے ہیں یہ شب بھر چاند ستارے
میری سوچوں پر یہ کون ہے خوف کے چھینٹے مارے
میری غزلیں, میری نظمیں, میرے نغمے سارے

بیسویں صدی كے مكالمات بین المذاہب كا تنقیدی جائزہ

Dialogue is a medium of human understanding. Through dialogue one can express himself clearly. In the modern times human civilization is globally facing so many challenges. In this situation inter-faith dialogue can bring peace in the world. Because it is dialogue which help men understand each other and bring them close to each other. But in the contemporary period inter-faith dialogues have almost failed to achieve the noble targets. This article seeks to disclose why inter-faith dialogues have so far proved meaningless.

Processing, Characterization, Structure and Ionic Conductivity of Disordered Pyrochlores, Ho2 Zryti1-Y 2O7 Holmium Zirconium-Titanate, Hzt

In this study, a number of compounds in the Ho2(ZryTi1-y)2O7 pyrochlore system, which undergoes an order-disorder structural transition from pyrochlore to a defect-fluorite type, were investigated. The materials were processed by mechanical milling, followed by a two-step sintering route. The structure was analyzed via Rietveld refinements using neutron powder diffraction (NPD) data, and further supported by X-ray diffraction (XRD) to identify the phases and determine the composition of the pyrochlore-fluorite transformation boundary at room temperature. The NPD refinement and XRD results show that compositions with 0.0 ≤ y ≤ 0.5 crystallized into a pyrochlore structure while the ones with 0.7 ≤ y ≤ 1.0 crystallized into the defect-fluorite structure. The composition with y=0.6 was found to be a two phase (pyrochlore and defect-fluorite) mixture. Neutron refinement results confirmed that the cation disorder was independent of the anion Frenkel disorder and also the degree of Frenkel disorder O(1)-O(3) was different from the O(2)-O(3) anion disorder. The relation between x-parameter and anion Frenkel disorder was found to be linear for the pyrochlore structure. Unit-cell parameters were obtained using Rietveld refinements for the whole series and were also calculated via the Nelson-Riley function. The ionic conductivity studies were undertaken via AC impedance analysis to determine the electronic behaviour and its relationship to the structural change in the available temperature range of 300–700°C. The trends in ionic conductivity and activation energy were explained on the basis of NPD and XRD data. The composition at the pyrochlore-fluorite boundary exhibited the lowest activation energy and highest ionic conductivity.