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X-Ray Computed Tomography and Nanomaterials as Contrast Agents for Tumor Diagnosis
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
R. G. Aswathy, D. Sakthi Kumar
Over the last decades, there have been rapid progresses in X-ray imaging, especially with computed tomography (CT) for the diagnosis and treatment of various diseases, such as tumors, cardiovascular diseases, etc. X ray-computed tomography (X-ray CT) is the second most efficient and cost-effective imaging modality after optical imaging. X-ray CT is one of the proficient medical imaging modality using tomography generated by computer processing. Digital geometry processing creates a three-dimensional (3D) image of the interior of the body from a two-dimensional (2D) X-ray image. CT generates data, which could be operated, through ‘windowing’ process, to determine structures based on blocking X-ray beam. Apart from medicine, CT is also used for non-destructive materials testing. For example, in archeological field, X-ray CT is used for imaging the contents of sarcophagi, or the DigiMorph project that uses a CT scanner to study biological and paleontological specimens.
The pixel's visual territory
Published in Linda Matthews, Design Strategies for Reimagining the City, 2022
Digital geometry, therefore, tends to privilege compelling formal associations of colour, contrast and brightness that are invisible in analogous image-making processes. Moreover, according to Gestalt principles, the digital camera's zoom operation to a close scale makes the alignment of pixels more prominent, producing figural cohesion and strengthening. Conversely, enlargement or a close-up view of the analogue image has a weakening effect, producing new visual information in the irregular and illegible form of tonal gradients, which yield a fuzzier and grainier picture.47 In this regard, the viewer is compelled to investigate different digital image scales to achieve new and highly phenomenal or ‘overriding’ experiences of the scene at a close scale, while the analogue viewer is not. The unexplored potency of digital geometry thus resides with its extension of the image's optical range and scale. The continual unveiling of its undisclosed geometries across a temporal frame presents new opportunities to exploit its secrets.
Digital geometry for image analysis and processing
Published in João Manuel, R. S. Tavares, R. M. Natal Jorge, Computational Modelling of Objects Represented in Images, 2018
Digital geometry is germane with discrete geometry that deals with similar and some other related matters from a bit more general perspective (see the topics of Mathematical Subject Classification number 52Cxx). In particular, discrete geometry includes a number of subjects (e.g., ones related to matroid theory) that are not directly related to computer imagery, and tackles them from more abstract point of view. Instead, digital geometry is closely focused on problems arising from image analysis and processing, computer graphics, and related disciplines. Below we list some basic subjects of digital geometry, among others.
Structural feature analysis of the vascular network in retinal images
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2019
O. Bandyopadhyay, T. Dutta, N. Dutta, A. Biswas, B. B. Bhattacharya
A. Biswasis an associate professor and head of Department of Information Technology, Indian Institute of Engineering Science and Technology, Shibpur, India. The author’s research interests are Digital Geometry and Image Analysis, Shape Analysis and Medical Image Analysis.
A 3D non-local density functional theory for any pore geometry
Published in Molecular Physics, 2020
Thomas Bernet, Manuel M. Piñeiro, Frédéric Plantier, Christelle Miqueu
All of these considerations draw an outline for this article. In a first part, the general tools describing the hard-sphere fluid (hs) and the attractive-sphere fluid with a square-well potential (sw), in the framework of NLDFT, are presented. Homogeneous reference for attractive spheres are described by the monomer of the statistical associating fluid theory of variable range (SAFT-VR) [26, 27]. The computation of weighted functions in a three-dimensional space, independently of the pore geometry is thus explained. In a second part, this formalism is applied to pores modelled by a hard-wall potential. The first example that is considered is a hard-sphere fluid confined in a cylindrical pore, in order to test the ability of our formalism to model curvatures. Then, a fixed spherical molecule is modelled by an external potential, and the distribution of other identical molecules of the fluid around the fixed one is computed. This example aims at recovering the pair correlation function of a homogeneous fluid, for a hard-sphere fluid and a square-well fluid. Molecular simulations are used as reference results to validate our formalism. Then, as a last example considering a hard wall, the confinement of a square-well fluid into a closed-end slit pore is considered. This fluid model, explored in previous works [28,29], is selected as an example of NLDFT with attractive spheres, but is described here for the first time in a multi-dimensional space. Moreover, we intend to show with this case the combination of confinement, closure, and edges in a single pore, with their consequences on local density distribution and global adsorbed quantity. In a last part, attractive continuous walls are considered because of their importance in adsorption studies of real systems and characterisation of porous materials. The first issue is the modelling of a fluid-solid interaction with a continuous general wall, with any kind of curvature, in a discretised computational space. In the first examples presented above, the external potentials are known and the aim is to test the efficiency of the 3D-DFT, comparing the results with those of molecular simulations or reference results, computed with the same potentials. In this last part, the aim is to test the high-quality of the external potential modelling (this problem is equivalent for theory and simulation). As this test does not concern a comparison between theory and simulations, we need to compare the external potential modelling with demonstrated mathematical results, related to discrete geometry [30] (or digital geometry), because of the discretisation of the computational space. We choose the case of attractive spheres confined in an attractive cylindrical pore to clearly test the expected symmetry of microscopic structure results. Obtaining density distributions, microscopic structure and interfacial properties constitutes one of the aims of this work, using the general 3D-DFT framework presented here.