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圖像分割是圖像處理中的一個非常重要的課題，其目的是辨認給定圖像中所包含物體的邊界。目前已經有很多非常有效的圖像分割方法，例如：基於模型的方法、模式識別技術、基於搜索的方法、基於人工智能的方法等等。在本論文中，我們主要討論兩類圖像分割問題，一類是醫學圖像中的血管分割問題，另一類是一般性圖像的分割問題，即對於例如醫學、噪聲和模糊等圖像，如何對其實現有效的雙級和多級分割。 / 在本論中的第一部分，我們討論第一個問題，即醫學圖像中的血管分割問題，我們將提出我們的基於tight-frame的血管分割方法。Tight-frame作為正交小波的一般情形，已經被成功的應用於圖像處理中的許多問題，包括：圖像修復、去除脈衝噪聲、高分辨率圖像恢復等等。在這部分，我們將應用tight-frame方法來自動識別醫學圖像中的管狀結構。我們的方法是反覆的改進血管的潛在邊界的區間。在迭代的每一步，我們用tight-frame方法來使血管的潛在邊界去噪和光滑，並同時壓縮血管的潛在邊界的區間。毎一步迭代的計算量跟所處理圖像的元素個數是成比例的。可以證明，我們的方法在有限步迭代後將自動收斂到一個二值圖像。在得到的二值图像中，血管部分可以直接分割出來。从构造的和真实的2D/3D圖像的數值例子中可以得出，我們的方法比現有的很多有代表性的分割方法來的更加精確，並且在很少步的迭代後收斂。 / 在本論中的第二部分，我們討論一般性的圖像分割問題。Mumford-Shah模型是一個非常重要的圖像分割模型，對其的深入研究已經經歷了20多年。在這部分，基於Mumford-Shah模型，我們將提出一種圖像分割的凸模型。它可以被看作是尋找一個光滑解g來估計Mumford-Shah模型的分段光滑解。當g得到後，把合適的閥值作用於g 即可實現圖像的雙級和多級分割。使用者可以自己選擇合適的閥值來揭示圖像的特殊特徵，也可以用K-means的方法來自動的選取閥值。由於我們所提模型的凸性，g可以用諸如split-Bregman或者Chambolle-Pock的方法來快速有效的求出。可以證明，我們所提出的模型有且只有一個解g。對於我們所提出的分割方法，在求出g之前不需要預先指定分割的級數K(K>=2)。當g求出後，選取(K-1)個合適的閥值即可實現圖像的K級分解，在閥值更換的情形下並不需要重新求解g。實驗結果表明，對於一般的圖像，例如：抗結塊，噪聲和模糊等圖像，我們的方法優於很多現有的有效的雙級和多級分割方法。 / Image segmentation is a very important topic in image processing. It is the process of identifying object outlines within images. There are quite a few efficient algorithms for segmentation such as the model based approaches, pattern recognition techniques, tracking-based approaches, artificial intelligence-based approaches, etc. In this thesis, we mainly study two kinds of image segmentation problems. More precisely, one kind problem is the vessel segmentation problem in medical imaging, the other is the generic image segmentation problem, i.e., two-phase and multiphase image segmentation for very general images, for example medical, noisy, and blurry images, etc. / In Part I of this thesis, we focus on the vessel segmentation problem in medical Images, and our tight-frame based vessel segmentation algorithm will be proposed. Tight-frame, a generalization of orthogonal wavelets, has been used successfully in various problems in image processing, including inpainting, impulse noise removal, super-resolution image restoration, etc. In this part, we propose to apply the tight-frame approach to automatically identify tube-like structures in medical imaging, with the primary application of segmenting blood vessels in magnetic resonance angiography images. Our method iteratively refines a region that encloses the potential boundary of the vessels. At each iteration, we apply the tight-frame algorithm to denoise and smooth the potential boundary and sharpen the region. The cost per iteration is proportional to the number of pixels in the image. We prove that the iteration converges in a finite number of steps to a binary image whereby the segmentation of the vessels can be done straightforwardly. Numerical experiments on synthetic and real 2D/3D images demonstrate that our method is more accuracy when compared with some representative segmentation methods, and it usually converges within a few iterations. / Part II of this thesis focuses on generic image segmentation problem. The Mumford-Shah model is one of the most important image segmentation models, and has been studied extensively in the last twenty years. In this part, based on the Mumford-Shah model, our convex image segmentation model will be proposed. It can be seen as finding a smooth approximation go to the piecewise smooth solution of the Mumford-Shah model. Once g is obtained, the two-phase or multiphase segmentation is done by thresholding g. The thresholds can be given by the users to reveal specific features in the image or they can be obtained automatically using a K-means method. Because of the convexity of our model, g can be solved efficiently by techniques like the split-Bregman algorithm or the Chambolle-Pock method. We prove that our model is convergent and the solution g is always unique. In our method, there is no need to specify the number of segments K (K ≥ 2) before finding g. We can obtain any K-phase segmentations by choosing (K-1) thresholds after g is found; and there is no need to recompute g if the thresholds are changed. Experimental results show that our method performs better than many standard 2-phase or multi-phase segmentation methods for very general images, including anti-mass, noisy, and blurry images. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Cai, Xiaohao. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 70-80). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Introduction to Chapter 2 (part I) on Vessel Segmentation in Medical Imaging Using a Tight-frame Based Algorithm --- p.2 / Chapter 1.2 --- Introduction to Chapter 3 (part II) on Image Segmentation by Convex Approximation of the Mumford-Shah Model --- p.5 / Chapter 2 --- Vessel Segmentation inMedical Imaging Using a Tightframe Based Algorithm --- p.9 / Chapter 2.1 --- Introduction --- p.9 / Chapter 2.2 --- Tight-Frame Algorithm --- p.11 / Chapter 2.3 --- Tight-Frame Based Algorithm for Segmentation --- p.14 / Chapter 2.4 --- Numerical Examples --- p.20 / Chapter 2.4.1 --- Synthetic vessel segmentation --- p.21 / Chapter 2.4.2 --- 2D vessel segmentation --- p.23 / Chapter 2.4.3 --- 3D vessel segmentation --- p.29 / Chapter 2.5 --- Conclusion and Future Work --- p.32 / Chapter 3 --- Image Segmentation by Convex Approximation of the Mumford-Shah Model --- p.39 / Chapter 3.1 --- Introduction --- p.39 / Chapter 3.2 --- Our model --- p.42 / Chapter 3.2.1 --- Derivation of our model --- p.43 / Chapter 3.2.2 --- Relationship with image restoration --- p.46 / Chapter 3.3 --- Numerical aspects --- p.47 / Chapter 3.3.1 --- Solution of our segmentation model --- p.47 / Chapter 3.3.2 --- Determining the thresholds --- p.50 / Chapter 3.4 --- Experimental results --- p.51 / Chapter 3.4.1 --- Two-phase segmentation --- p.52 / Chapter 3.4.2 --- Multiphase segmentation --- p.58 / Chapter 3.5 --- Conclusions --- p.62 / Chapter 4 --- Conclusions --- p.65 / Chapter 5 --- Appendix --- p.67 / Bibliography --- p.70

Image segmentation is a fundamental part in low level computer vision processing. It has an essential influence on the subsequent higher level visual scene interpretation for a wide range of applications. Unsupervised image segmentation is an ill-defined problem and thus cannot be optimally solved in general. Several novel unsupervised multispectral image segmentation methods based on the underlaying random field texture models (GMRF, 2D/3D CAR) were developed. These segmenters use efficient data representations that allow an analytical solutions and thus the segmentation algorithm is much faster in comparison to methods based on MCMC. All segmenters were extensively compared with the alternative state- of-the-art segmenters with very good results. The MW3AR segmenter scored as one of the best available. The cluster validation problem was solved by a modified EM algorithm. Two multiple resolution segmenters were designed as a combination of a set of single segmenters. To tackle a realistic variable lighting in images, the illumination invariant features were derived and the illumination invariant segmenter was developed. For the proper evaluation of segmentation results and ranking of algorithms, a unique web-based texture segmentation benchmark was proposed and implemented. It was used for comprehensive...

Neutrosophy studies the origin, nature, scope of neutralities, and their interactions with different ideational spectra. It is a new philosophy that extends fuzzy logic and is the basis of neutrosophic logic, neutrosophic probability, neutrosophic set theory, and neutrosophic statistics. Because the world is full of indeterminacy, the imperfection of knowledge that a human receives/observes from the external world also causes imprecision. Neutrosophy introduces a new concept , which is the representation of indeterminacy. However, this theory is mostly discussed in physiology and mathematics. Thus, applications to prove this theory can solve real problems are needed. Image segmentation is the first and key step in image processing. It is a critical and essential component of image analysis and pattern recognition. In this dissertation, I apply neutrosophy to three types of image segmentation: gray level images, breast ultrasound images, and color images. In gray level image segmentation, neutrosophy helps reduce noise and extend the watershed method to normal images. In breast ultrasound image segmentation, neutrosophy integrates two controversial opinions about speckle: speckle is noise versus speckle includes pattern information. In color image segmentation, neutrosophy integrates color and spatial information, global and local information in two different color spaces: RGB and CIE (L*u*v*), respectively. The experiments show the advantage of using neutrosophy.

In many image-processing applications, one object of interest must be segmented. The techniques used for segmentation vary depending on the particular situation and the specifications of the problem at hand. In methods that rely on a learning process, the lack of a sufficient number of training samples is usually an obstacle, especially when the samples need to be manually prepared by an expert. The performance of some other methods may suffer from frequent user interactions to determine the critical segmentation parameters. Also, none of the existing approaches use online (permanent) feedback, from the user, in order to evaluate the generated results. Considering the above factors, a new multi-stage image segmentation system, based on Reinforcement Learning (RL) is introduced as the main contribution of this research. In this system, the RL agent takes specific actions, such as changing the tasks parameters, to modify the quality of the segmented image. The approach starts with a limited number of training samples and improves its performance in the course of time. In this system, the expert knowledge is continuously incorporated to increase the segmentation capabilities of the method. Learning occurs based on interactions with an offline simulation environment, and later online through interactions with the user. The offline mode is performed using a limited number of manually segmented samples, to provide the segmentation agent with basic information about the application domain. After this mode, the agent can choose the appropriate parameter values for different processing tasks, based on its accumulated knowledge. The online mode, consequently, guarantees that the system is continuously training and can increase its accuracy, the more the user works with it. During this mode, the agent captures the user preferences and learns how it must change the segmentation parameters, so that the best result is achieved. By using these two learning modes, the RL agent allows us to optimally recognize the decisive parameters for the entire segmentation process.

In many image-processing applications, one object of interest must be segmented. The techniques used for segmentation vary depending on the particular situation and the specifications of the problem at hand. In methods that rely on a learning process, the lack of a sufficient number of training samples is usually an obstacle, especially when the samples need to be manually prepared by an expert. The performance of some other methods may suffer from frequent user interactions to determine the critical segmentation parameters. Also, none of the existing approaches use online (permanent) feedback, from the user, in order to evaluate the generated results. Considering the above factors, a new multi-stage image segmentation system, based on Reinforcement Learning (RL) is introduced as the main contribution of this research. In this system, the RL agent takes specific actions, such as changing the tasks parameters, to modify the quality of the segmented image. The approach starts with a limited number of training samples and improves its performance in the course of time. In this system, the expert knowledge is continuously incorporated to increase the segmentation capabilities of the method. Learning occurs based on interactions with an offline simulation environment, and later online through interactions with the user. The offline mode is performed using a limited number of manually segmented samples, to provide the segmentation agent with basic information about the application domain. After this mode, the agent can choose the appropriate parameter values for different processing tasks, based on its accumulated knowledge. The online mode, consequently, guarantees that the system is continuously training and can increase its accuracy, the more the user works with it. During this mode, the agent captures the user preferences and learns how it must change the segmentation parameters, so that the best result is achieved. By using these two learning modes, the RL agent allows us to optimally recognize the decisive parameters for the entire segmentation process.

In this paper, we propose a Kalman filtering method to restore signal when both the digital and analog signal are available. The digital video signal is coded by method of MPEG. The error can be introduced in the quantization process of the block DCT transformation. So the quality of the image from the digital video signal needs to be improved. Considering the analog video signal is corrupted by the Gauss White Noise. We can apply the Kalman filter to these two signals at the same time to restore the image for a better quality. The image structure is defined to be the linear relationship between pixels with their upper and left neighbors. So we can determinate the image structure property by the linear equations of the pixel gray level. Generally, the image segmentation takes the gray values as the property. In our case we take the linear equations as our property function. This property implies an abstract concept and can¡¦t measure directly. We determine the unity of the image structure by measuring the error from merging the pixel into one region. We achieve a recursive formula for computing the error by the sequential least square error method. In the signal processing, Kalman filter is used for optimal estimation of the signal corrupted by additive noise. We segment the image by its local property. By our segmentation technique every region has its specific image structure. The structures are system parameters of Kalman filter. We first utilize the method of segmentation on the image recovered from the MPEG signal to find the local parameters. The results of experiments show that we can improve the images quality when the MPEG signal is not very good.

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Two-photon calcium imaging (TPCI) is a functional neuroimaging technique that simultaneously reveals the function of small populations of cells as well as the structure of surrounding brain tissue. These unique properties cause TPCI to be increasingly popular for experimental basic neuroscience. Unfortunately, methodological development for data processing has not kept pace with experimental needs. I address this lack by developing and testing new methodology for several key tasks. Specifically, I address two primary analysis steps which are nearly universally required in early data processing: region of interest segmentation and motion correction. For each task I organize the sparse existing literature, clearly define the requirements of the problem, propose a solution, and evaluate it on experimental data. I develop MaSCS, an automated adaptable multi-class segmentation system that improves with use. I carefully define and describe the impact of motion artifacts on imaging data, and quantify the effects of standard and innovative motion correction approaches. Finally, I apply my work on segmentation and motion correction to explore one scientific target, namely discovering correlation-based cell clustering. I show that estimating such correlation-based clustering remains an open question, as it is highly sensitive to motion artifacts, even after motion correction techniques are applied. The contributions of this work include the organization of existing resources, methodological advances in segmentation, motion correction and clustering, and the development of prototype analysis software.