摘要 :
This paper studies the feasibility of enhancing the spatial resolution of multilook Multispectral Thermal Imager (MTI) imagery using an iterative resolution enhancement algorithm known as Projection Onto Convex Sets (POCS). A mult...
展开
This paper studies the feasibility of enhancing the spatial resolution of multilook Multispectral Thermal Imager (MTI) imagery using an iterative resolution enhancement algorithm known as Projection Onto Convex Sets (POCS). A multiangle satellite image modeling tool is implemented, and simulated multilook MTI imagery is formed to test the resolution enhancement algorithm. Experiments are done to determine the optimal configuration and number of multiangle low-resolution images needed for a quantitative improvement in the spatial resolution of the high-resolution estimate. The issues of atmospheric path radiance and directional reflectance variations are explored to determine their effect on the resolution enhancement performance.
收起
摘要 :
Transform image processing methods are methods that work in domains of image transforms, such as discrete fourier, discrete cosine, wavelet and alike. They are the basic tools in image compression, image restoration, image resampl...
展开
Transform image processing methods are methods that work in domains of image transforms, such as discrete fourier, discrete cosine, wavelet and alike. They are the basic tools in image compression, image restoration, image resampling and geometrical transformations and can be traced back to the early 1970s. The paper presents a review of these methods with emphasis on their comparison and relationships, from the very first steps of transform image compression methods to adaptive and local adaptive transform domain filters for image restoration, to methods of precise image resampling and image reconstruction from sparse samples and up to the 'compressive sensing' approach that has gained popularity in the last few years. The review has a tutorial character and purpose.
收起
摘要 :
This paper presents Magnetic Resonance Imaging (MRI) brain tumor detection utilizing Fuzzy C Means strategy with an upgraded noise filtering calculation. A novel technique is proposed to enhance the execution of cerebrum tumor dis...
展开
This paper presents Magnetic Resonance Imaging (MRI) brain tumor detection utilizing Fuzzy C Means strategy with an upgraded noise filtering calculation. A novel technique is proposed to enhance the execution of cerebrum tumor discovery. A new calculation for noise filtering is adapted to extract the correct area of tumor, where execution is enhanced by upgrading the threshold task in wavelet filtering strategy as a preprocessing step. Trial results demonstrate that by utilizing proposed calculation, the filtering procedure gives better execution when contrasted with the current methods. The average value of Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index Measure (SSIM) for Gaussian noise is improved by 40% and 41.06% and for Rician noise, which is 13.73% and 25.39% higher than the state-of-art methods. After filtering, segmentation is done to point out the tumor region. For segmentation, Otsu and FCM methods are adapted here and a comparison is made between these two methods. Experimental results show that Jaccard and Dice coefficient of Fuzzy C Means (FCM) with enhanced filtering is increased by 3.6% and 1.3% compared to the methods available in the literature.
收起
摘要 :
Image fusion has been receiving increasing attention in the research community with the aim of investigating general formal solutions to a wide spectrum of applications such as multifocus, multiexposure, multispectral (\(IR\)-visi...
展开
Image fusion has been receiving increasing attention in the research community with the aim of investigating general formal solutions to a wide spectrum of applications such as multifocus, multiexposure, multispectral (\(IR\)-visible) and multimodal medical (CT and MRI) image and video fusion. While there exist many fusion techniques for each of these applications, it is difficult to formulate a common fusion technique that works equally well for all these applications. This is mainly because of the different characteristics of the images involved in various applications and the correspondingly different requirements on the fused image. In this work, we propose a common generalized fusion framework for all these classes, based on the statistical properties of local neighborhood of a pixel. As the eigenvalue of the unbiased estimate of the covariance matrix of an image block depends on the strength of edges in that block, we propose to employ it to compute a quantity we call as the significance of a pixel. This generalized pixel significance in turn can be used as a measure of the useful information content in that block, and hence can be used in the fusion process. Several data sets were fused to compare the results with various recently published methods. The analysis shows that for all the image types into consideration, the proposed methods improve the quality of the fused image, both visually and quantitatively, by preserving all the relevant information.
收起
摘要 :
Optical coherence tomography (OCT) is a promising real-time and non-invasive imaging technology widely utilized in biomedical and material inspection domains. However, limited field of view (FOV) in conventional OCT systems hamper...
展开
Optical coherence tomography (OCT) is a promising real-time and non-invasive imaging technology widely utilized in biomedical and material inspection domains. However, limited field of view (FOV) in conventional OCT systems hampers their broader applicability. Here, we propose an automated system integrating a structured light camera and robotic arm for large-area OCT scanning. The system precisely detects tissue contours, automates scan path generation, and enables accurate scanning of expansive sample areas. The proposed system consists of a robotic arm, a three-dimensional (3D) structured light camera, and a customized portable OCT probe. The 3D structured light camera is employed to generate a precise 3D point cloud of the sample surface, enabling automatic planning of the scanning path for the robotic arm. Meanwhile, the OCT probe is mounted on the robotic arm, facilitating scanning of the sample along the predetermined path. Continuous OCT B-scans are acquired during the scanning process, facilitating the generation of high-resolution and large-area 3D OCT reconstructions of the sample. We conducted position error tests and presented examples of 3D macroscopic imaging of different samples, such as ex vivo kidney, skin and leaf blade. The robotic arm can accurately reach the planned positions with an average absolute error of approximately 0.16 mm. The findings demonstrate that the proposed system enables the acquisition of 3D OCT images covering an area exceeding 20?cm <sup>2</sup> , indicating wide-ranging potential for utilization in diverse domains such as biomedical, industrial, and agricultural fields.
收起
摘要 :
Images are often considered as functions defined on the image domains, and as functions, their (intensity) values are usually considered to be invariant under the image domain transforms. This functional viewpoint is both influent...
展开
Images are often considered as functions defined on the image domains, and as functions, their (intensity) values are usually considered to be invariant under the image domain transforms. This functional viewpoint is both influential and prevalent, and it provides the justification for comparing images using functional L-p-norms. However, with the advent of more advanced sensing technologies and data processing methods, the definition and the variety of images has been broadened considerably, and the long-cherished functional paradigm for images is becoming inadequate and insufficient. In this paper, we introduce the formal notion of covariant images and study two types of covariant images that are important in medical image analysis, symmetric positive-definite tensor fields and Gaussian mixture fields, images whose sample values covary i.e., jointly vary with image domain transforms rather than being invariant to them. We propose a novel similarity measure between a pair of covariant images considered as embedded shapes (manifolds) in the ambient space, a Cartesian product of the image and its sample-value domains. The similarity measure is based on matching the two embedded low-dimensional shapes, and both the extrinsic geometry of the ambient space and the intrinsic geometry of the shapes are incorporated in computing the similarity measure. Using this similarity as an affinity measure in a supervised learning framework, we demonstrate its effectiveness on two challenging classification problems: classification of brain MR images based on patients' age and (Alzheimer's) disease status and seizure detection from high angular resolution diffusion magnetic resonance scans of rat brains.
收起
摘要 :
Magnetic Resonance Imaging (MRI) is a powerful imaging tool that combined with the use of contrast agents (CA) provides meaningful and crucial information both in the research and clinical settings. In recent years, strides have b...
展开
Magnetic Resonance Imaging (MRI) is a powerful imaging tool that combined with the use of contrast agents (CA) provides meaningful and crucial information both in the research and clinical settings. In recent years, strides have been taken towards the development of new CAs with enhanced capabilities (specificity, responsiveness, multimodality ...) to better diagnose and monitor physiological and pathological conditions in the body. Despite recent development, there are still challenges in the use of MRI to quantify specific functional or metabolic processes. The application of a ratiometric approach, in which images are acquired from the same sample using two different MR acquisitions, has potential to greatly improve the utility of MRI. In order to make this ratiometric approach work, a new generation of ratiometric probes are being developed which will be discussed in this review, classifying them based on the biological parameter under study as well as on the ratiometric analysis approach. Finally, the advantages and feasibility of using this methodology in a routine way will also be discussed. (C) 2021 Elsevier B.V. All rights reserved.
收起
摘要 :
Techniques of medical image processing and analysis play a crucial role in many clinical scenarios, including in diagnosis and treatment planning. However, immense quantities of data and high complexity of the algorithms often use...
展开
Techniques of medical image processing and analysis play a crucial role in many clinical scenarios, including in diagnosis and treatment planning. However, immense quantities of data and high complexity of the algorithms often used are computationally demanding. As a result, there now exists a wide range of techniques of medical image processing and analysis that require the application of high-performance computing solutions in order to reduce the required runtime. The main purpose of this review is to provide a comprehensive reference source of techniques of medical image processing and analysis that have been accelerated by high-performance computing solutions. With this in mind, the articles available in the Scopus and Web of Science electronic repositories were searched. Subsequently, the most relevant articles found were individually analyzed in order to identify: (a) the metrics used to evaluate computing performance, (b) the high-performance computing solution used, (c) the parallel design adopted, and (d) the task of medical image processing and analysis involved. Hence, the techniques of medical image processing and analysis found were identified, reviewed, and discussed, particularly in terms of computational performance. Consequently, the techniques reviewed herein present the progress made so far in reducing the computational runtime involved, and the difficulties and challenges that remain to be overcome.
收起
摘要 :
The progression of atherosclerosis involves complex changes in the structure, composition and biology of the artery wall. Currently, only anatomical plaque burden is routinely characterized in living patients, whereas compositiona...
展开
The progression of atherosclerosis involves complex changes in the structure, composition and biology of the artery wall. Currently, only anatomical plaque burden is routinely characterized in living patients, whereas compositional and biological changes are mostly inaccessible. However, anatomical imaging alone has proven to be insufficient for accurate diagnostics of the disease. Multispectral optoacoustic tomography offers complementary data to anatomical methods and is capable of imaging both tissue composition and, via the use of molecular markers, the biological activity therein. In this paper we review recent progress in multispectral optoacoustic tomography imaging of atherosclerosis with specific emphasis on intravascular applications. The potential capabilities of multispectral optoacoustic tomography are compared with those of established intravascular imaging techniques and current challenges on the road towards a clinically viable imaging modality are discussed.
收起
摘要 :
Ultrafast ultrasound imaging has become an intensive area of research thanks to its capability in reaching high frame rates. In this paper, we propose a scheme that allows the extension of the current Fourier-based techniques deri...
展开
Ultrafast ultrasound imaging has become an intensive area of research thanks to its capability in reaching high frame rates. In this paper, we propose a scheme that allows the extension of the current Fourier-based techniques derived for planar acquisition to the reconstruction of sectorial scan with wide angle using diverging waves. The flexibility of the proposed formulation was assessed through two different Fourier-based techniques. The performance of the derived approaches was evaluated in terms of resolution and contrast from both simulations and in vitro experiments. The comparisons of the current state-of-the-art method with the conventional delay-and-sum technique illustrated the potential of the derived methods for producing competitive results with lower computational complexity.
收起
原文获取