An image enhancement effect objective assessment method based on visual information fidelity

2010 ◽  
Author(s):  
Xiusheng Liu ◽  
Hongsheng Yu ◽  
Yanqing Dai
Keyword(s):  
Image Enhancement ◽  
Visual Information ◽  
Objective Assessment ◽  
Assessment Method ◽  
Enhancement Effect ◽  
Information Fidelity

scholarly journals Geometric Regularized Hopfield Neural Network for Medical Image Enhancement

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Fayadh Alenezi ◽  
K. C. Santosh
Keyword(s):  
Neural Network ◽  
Visual Information ◽  
Medical Image ◽  
Signal To Noise Ratio ◽  
Hopfield Neural Network ◽  
Network Stability ◽  
Signal To Noise ◽  
Convergence Problem ◽  
Information Fidelity ◽  
Medical Image Enhancement

One of the major shortcomings of Hopfield neural network (HNN) is that the network may not always converge to a fixed point. HNN, predominantly, is limited to local optimization during training to achieve network stability. In this paper, the convergence problem is addressed using two approaches: (a) by sequencing the activation of a continuous modified HNN (MHNN) based on the geometric correlation of features within various image hyperplanes via pixel gradient vectors and (b) by regulating geometric pixel gradient vectors. These are achieved by regularizing proposed MHNNs under cohomology, which enables them to act as an unconventional filter for pixel spectral sequences. It shifts the focus to both local and global optimizations in order to strengthen feature correlations within each image subspace. As a result, it enhances edges, information content, contrast, and resolution. The proposed algorithm was tested on fifteen different medical images, where evaluations were made based on entropy, visual information fidelity (VIF), weighted peak signal-to-noise ratio (WPSNR), contrast, and homogeneity. Our results confirmed superiority as compared to four existing benchmark enhancement methods.

scholarly journals Regular Physical Activity and Risk of Venous Thromboembolism

2018 ◽  
Vol 44 (08) ◽  
pp. 765-779 ◽  
Author(s):  
Sigrid Brækkan ◽  
John-Bjarne Hansen ◽  
Line Evensen
Keyword(s):  
Physical Activity ◽  
Venous Thromboembolism ◽  
Current Knowledge ◽  
Objective Assessment ◽  
Operational Definition ◽  
Assessment Method ◽  
Health Concern ◽  
Future Research ◽  
Dependent Manner

AbstractVenous thromboembolism (VTE) is a complex multifactorial disease that represents a growing public health concern. Identification of modifiable risk factors at the population level may provide a measure to reduce the burden of VTE. In this review, we summarize current knowledge of the role of physical activity on the risk of VTE and VTE-related complications. We also discuss methodological challenges related to research on physical activity, and put forward plausible mechanisms for an association between physical activity and VTE. Up to now, published studies have reported diverging results on the relationship between physical activity and VTE, and a complex picture has emerged. However, the available evidence appears to be balanced toward a small beneficial effect of physical activity on the risk of incident VTE, but not in a dose-dependent manner. Still, the lack of an operational definition and standardized assessment method for physical activity, as well as several sources of bias, impairs the interpretation of the available literature. Additional work is necessary to understand the role and how to apply physical activity in the VTE setting. Future research should utilize objective assessment strategies of physical activity and physical fitness, account for the fluctuating nature in habitual activity levels, and explore the role of physical activity in the areas of secondary prevention and VTE-related complications.

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