Background: Digital images are captured using sensors during the data acquisition phase, where they are often contaminated by noise (an undesired random signal). Such noise can also be produced during transmission or by poor-quality lossy image compression. Reducing the noise and enhancing the images are considered the central process to all other digital image processing tasks. The improvement in the performance of image denoising methods would contribute greatly on the results of other image processing techniques. Patch-based denoising methods recently have merged as the state-of-the-art denoising approaches for various additive noise levels. In this work, the use of the state-of-the-art patch-based denoising methods for additive noise reduction is investigated. Various types of image datasets are addressed to conduct this study.
Methods: We first explain the type of noise in digital images and discuss various image denoising approaches, with a focus on patch-based denoising methods. Then, we experimentally evaluate both quantitatively and qualitatively the patch-based denoising methods. The patch-based image denoising methods are analyzed in terms of quality and computational time.
Results: Despite the sophistication of patch-based image denoising approaches, most patch-based image denoising methods outperform the rest. Fast patch similarity measurements produce fast patch-based image denoising methods.
Conclusion: Patch-based image denoising approaches can effectively reduce noise and enhance images. Patch-based image denoising approach is the state-of-the-art image denoising approach.
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http://dx.doi.org/10.1186/s13640-017-0203-4 | DOI Listing |
Background: Mild Cognitive Impairment (MCI) represents an intermediate stage between normal age-related cognitive decline and more severe degenerative conditions such as Alzheimer's disease. Understanding the differences between Early-MCI (EMCI) and Late-MCI (LMCI) is crucial to facilitate early diagnosis and future clinical interventions. This study employed free-water diffusion tensor imaging (FW-DTI) to explore the differences in white matter alterations between EMCI and LMCI.
View Article and Find Full Text PDFBackground: The increasing prevalence of cognitive impairment and dementia threatens global health, necessitating the development of accessible tools for detection of cognitive impairment. This study explores using a transformer-based approach to detect cognitive impairment using acoustic markers of spontaneous speech.
Method: Recordings of unstructured interviews from baseline visits were obtained from participants of The 90+ Study, a longitudinal study of individuals older than 90 years.
Alzheimers Dement
December 2024
Ajou University School of Medicine, Korea, Suwon, Korea, Republic of (South).
Background: The extent of neurofibrillary changes, one of the pathological hallmarks of AD, correlates with the severity of AD in dementia. The brainstem is known to be the site of neurofibrillary changes in the early stages of Alzhimer's disease. The neurotransmitter system in the brainstem processes information from subcortical and cortical circuits affect to various cognitive and behavioral responses in the cerebral cortex.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Imaging Genetics Center, Mark and Mary Stevens Neuroimaging & Informatics Institute, University of Southern California, Marina del Rey, CA, USA.
Background: Along-tract analysis of white matter (WM) bundles can help map detailed patterns of WM pathway degeneration in Alzheimer's disease. Here, we present Medial Tractography Analysis (MeTA), which aims to minimize partial voluming and microstructural heterogeneity in diffusion MRI (dMRI) metrics by extracting and parcellating the volume along the bundle length while preserving bundle shape and capturing variation within and along WM bundles. We evaluated along-tract WM microstructure associations with clinical measures in ADNI using MeTA.
View Article and Find Full Text PDFPhys Med Biol
January 2025
The Division of Imaging Sciences and Biomedical Engineering, King's College London, 5th Floor Becket House, London, SE1 7EH, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
Multiplexed positron emission tomography (mPET) imaging allows simultaneous observation of physiological and pathological information from multiple tracers in a single PET scan. Although supervised deep learning has demonstrated superior performance in mPET image separation compared to purely model-based methods, acquiring large amounts of paired single-tracer data and multi-tracer data for training poses a practical challenge and needs extended scan durations for patients. In addition, the generalisation ability of the supervised learning framework is a concern, as the patient being scanned and their tracer kinetics may potentially fall outside the training distribution.
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