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Effect of temperature on digital images of speckle patterns generated by a metallic rough surface
摘要： It is well known that roughness can be inferred from digital images of speckle patterns generated by illuminated rough surfaces, by analyzing parameters such as fractal dimension, lacunarity and correlation, to cite a few. In this article, we investigate the effect of temperature on the speckle pattern generated by the light scattered from a metallic rough surface. We show that fractal dimension is less sensitive to temperature changes than are lacunarity and correlation, and provide information about which method is more suitable for processing the speckle patterns produced by rough surfaces under temperature variation.
关键词： Speckle pattern,Fractal dimension,Correlation,Roughness,Lacunarity,Temperature
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Workshop on Complexity in Engineering (COMPENG) - Florence, Italy (2018.10.10-2018.10.12)] 2018 IEEE Workshop on Complexity in Engineering (COMPENG) - Fractal-Radiomics as Complexity Analysis of CT and MRI Cancer Images
摘要： Cancer is the second leading cause of death globally. Early diagnosis can allow intervention to reduce mortality but due to cancer complex structure and spatial heterogeneity among different tumors and within each lesion, it is difficult to differentiate it from healthy tissue using conventional imaging techniques. Quantification of its complexity can be a prognostic tool for fighting this disease. In recent years, clinical imaging allows this quantification thanks to Radiomics, which extracts features from images. In this study, Fractal Dimension (FD) and Lacunarity (L) in computed tomography (CT) and magnetic resonance (MR) images for different kinds of cancer were examined using box counting method. Our aim is to highlight the potentiality of features based on fractal analysis, in order to obtain new indicators able to detect tumor spatial complexity and heterogeneity. The results indicated that both FD and L show problems linked to the lack of connection between complexity estimated with Radiomics and the underlying biological model.
关键词： cancer heterogeneity,lacunarity,complexity,fractal analysis,cancer,Radiomics
更新于2025-09-23 15:21:01
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Multifractal and Lacunarity Analyses of Microvascular Morphology in Eyes with Diabetic Retinopathy: A Projection Artifact Resolved Optical Coherence Tomography Angiography Study
摘要： Objective: To evaluate the degree of microvascular impairment in diabetic retinopathy using multifractal and lacunarity analyses and to compare the diagnostic ability between traditional Euclidean measures (fovea avascular zone area and vessel density) and fractal geometric features. Methods: This retrospective cross-sectional study included a total of 143 eyes of 94 patients with different stages of diabetic retinopathy. The retinal microvasculature was imaged by projection removed optical coherence tomography angiography. We examined the degree of association between fractal metrics of the retinal microvasculature and diabetic retinopathy severity. The area under the receiver operating characteristic curve was used to estimate the diagnostic performance. Results: With increasing diabetic retinopathy severity, the multifractal spectrum shifted towards the left bottom and exhibited less left skewness and asymmetry. The vessel density, multifractal features and lacunarity measured from the deep capillary plexus were strongly associated with diabetic retinopathy severity. The multifractal feature D5 showed the highest diagnostic ability. The combination of multifractal features further improved the discriminating power. Conclusions: Multifractal and lacunarity analyses can be potentially valuable tools for assessment of microvascular impairments in diabetic retinopathy. Multifractal geometric parameters exhibit a better discriminatory performance than Euclidean measures, particularly for detection of the early stages of diabetic retinopathy.
关键词： diabetic retinopathy,optical coherence tomography angiography,microvascular network,lacunarity,multifractal
更新于2025-09-04 15:30:14