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41.
Mathematical definition and analysis of the retinex algorithm 总被引:1,自引:0,他引:1
Provenzi E De Carli L Rizzi A Marini D 《Journal of the Optical Society of America. A, Optics, image science, and vision》2005,22(12):2613-2621
We present a detailed mathematical analysis of the original Retinex algorithm due to Land and McCann [J. Opt. Soc. Am. 61, 1 (1071)]. To this end, we propose an analytic formula that describes the algorithm behavior. More than one Retinex version (e.g., with and without threshold) is examined. The behavior of Retinex varying the number of paths is predicted, and its recursive iterations are mathematically analyzed using the formula. The mathematical setting presented serves as a common ground for the various Retinex implementations. Its validity is confirmed by the tests on images that we have performed. 相似文献
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E. Piperopoulos L. Calabrese E. Mastronardo S. H. Abdul Rahim E. Proverbio C. Milone 《应用聚合物科学杂志》2019,136(14):47374
Sorption kinetics of pollutant oils, such as kerosene, virgin naphtha, crude oil, and pump oil, into porous siloxanic foams filled with carbon nanotubes (CNTs) are investigated. Both, pristine and functionalized, CNTs are used as foam fillers. Among all, the foam filled with pristine CNT shows a poor affinity with water and high sorption rate in light oils, in which it achieves the highest absorption values (7991 mg g−1 after 660 s and 6685 mg g−1 after 420 s, respectively, in virgin naphtha and kerosene). The kinetic data are described by the pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models. Results show that chemisorption processes are rate limiting the sorption step. In fact, pseudo-second order model better represents the equilibrium isotherm data. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47374. 相似文献
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Edoardo Capuano Nicoletta Pellegrini 《Journal of the science of food and agriculture》2019,99(2):493-498
The true bioavailability of a nutrient being intrinsically coupled to the specific food matrix in which it occurs remains poorly considered in nutrition science. During digestion, the food matrix and, in particular, the structure of food modulate the extent and kinetics to which nutrients and bioactive compounds make themselves available for absorption. In this perspective, we describe an integrated look at the effect of structure on nutrient bioavailability in plant foods. Based on this integrated look, cell wall integrity and the particle size of the plant material during its transit in the small intestine determine the bioavailability of plant nutrients; in turn, cell wall integrity and particle size are determined by the level of oral processing and, accordingly, what subsequently escapes digestion in the upper intestine and is utilized by colon microbiota. Ultimately, the effect on nutrient digestion is linked to food structure through each step of digestion. A consideration of the structure rather than just the composition of foods opens up possibilities for the design of healthier foods. © 2018 Society of Chemical Industry 相似文献
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Minds and Machines - Simulation studies have been carried out in robotics for a variety of epistemic and practical purposes. Here it is argued that two broad classes of simulation studies can be... 相似文献
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Edoardo Milana Benjamin Gorissen Sam Peerlinck Michael De Volder Dominiek Reynaerts 《Advanced functional materials》2019,29(22)
In nature, liquid propulsion in low‐Reynolds‐number regimes is often achieved by arrays of beating cilia with various forms of motion asymmetry. In particular, spatial asymmetry, where the cilia follow a different trajectory in their effective and recovery strokes, is an efficient way of generating flow in low Reynolds regimes. However, this type of asymmetry is difficult to mimic and control artificially. In this paper, an artificial soft cilium that comprises two pneumatic actuators that can be controlled individually is developed. These two independent degrees of freedom allow for the first time adjustment and study of spatial asymmetry in the cilium's beating pattern. Using low‐Reynolds‐number flow measurements, it is confirmed that spatial asymmetry allows for the generation of fluid propulsion. These two‐degree‐of‐freedom soft cilia provide a platform to study ciliary fluid transport mechanisms and to mimic biologic viscous propulsion. 相似文献
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Creep-fatigue assessment procedures for the design of high-temperature components should ensure lifetime predictions which are safe but not excessively conservative. Adoption of more accurate assessment procedures than are presently available enable the availability of power plant with greater operating flexibility. Operating flexibility is becoming a key market driver due to the increased interest in the use of intermittent renewable energy sources (e.g. wind, solar) which place focus on a requirement for turbo-machinery to be capable of reduced start-up and shut-down times. This study introduces a creep-fatigue assessment procedure for the design of high-temperature components required for flexible operation. In particular, it considers alloys with high creep-fatigue deformation/damage interaction characteristics such as the advanced martensitic 9–11%Cr steels which are widely used for power plant applications. The procedure takes advantages of advanced constitutive models and implements them in a state-of-the-art mechanical assessment procedure for calculating high-temperature component life times. 相似文献
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Edoardo Menga María J. Sánchez Ignacio Romero 《International journal for numerical methods in engineering》2020,121(5):904-924
Nonintrusive methods are now established in the engineering community as a pragmatic approach for the uncertainty quantification (UQ) and global sensitivity analysis (GSA) of complex models. However, especially for computationally expensive models, both types of analyses can only be completed by employing surrogates that replace the original models and are considerably less expensive. This work studies the construction of accurate and predictive meta-models for their use in both UQ and GSA, and their application to complex problems in nonlinear mechanics. In particular, meta-models based on radial functions are examined and enhanced with anisotropic metrics for improved predictiveness and cost effectiveness. Three numerical examples illustrate the performance of the proposed methodology. 相似文献