Speckle Noise Reduction using Local Binary Pattern

AbstractA novel local binary pattern (LBP) based adaptive diffusion for speckle noise reduction is presented. The LBP operator unifies traditionally divergent statistical and structural models of region analysis. We use LBP textons to classify an image around a pixel into noisy, homogenous, corner and edge regions. According to different types of regions, a variable weight is assigned in to the diffusion equation, so that our algorithm can adaptively encourage strong diffusion in homogenous/noisy regions and less on the edge/corner regions. The diffusion preserves edges, local details while diffusing more on homogenous region. The experiments results are evaluated both in terms of objective metric and the visual quality

A facile and green route to terpene derived acrylate and methacrylate monomers and simple free radical polymerisation to yield new renewable polymers and coatings

We present new acrylic monomers derived directly from abundant naturally available terpenes via a facile, green and catalytic approach. These monomers can be polymerised to create new polymers with a wide range of mechanical properties that positions them ideally for application across the commodity and specialty plastics landscape; from packaging, cosmetic and medical, through to composites and coatings. We demonstrate their utility through formation of novel renewable polymer coatings

Algebraic Iterative Reconstruction-Reprojection (AIRR) Method for High Performance Sparse-View CT Reconstruction

The reconstruction from sparse- or few-view projections is one of important problems in computed tomography limited by the availability or feasibility of a large number of projections. Working with a small number of projections provides a lower radiation dose and a fast scan time, however an error associated with the sparse-view reconstruction increases significantly as the space sparsity increases that may cause the reconstruction process to diverge. The iterative reconstruction-re-projection (IRR) algorithm which uses filtered back projection (FBP) reconstruction has been used for the sparse-view computed tomography applications for several years. The IRR-TV method has been developed as a higher performance alternative to the IRR method by adding the total variation (TV) minimization. Here, we propose an algebraic iterative reconstruction-re-projection (AIRR) algorithm with the shearlet regularization. The AIRR coupled with the shearlet regularization in image space attains a better estimation in the projection space and yielded a higher performance based on subjective and objective quality metrics

LFAD: Locally- and Feature-Adaptive Diffusion based Image Denoising

LFAD is a novel locally- and feature-adaptive diffusion based method for removing additive white Gaussian (AWG) noise in images. The method approaches each image region individually and uses a different number of diffusion iterations per region to attain the best objective quality according to the PSNR metric. Unlike block-transform based methods, which perform with a predetermined block size, and clustering-based denoising methods, which use a fixed number of classes, our method searches for an optimum patch size through an iterative diffusion process. It is initialized with a small patch size and proceeds with aggregated (i.e., merged) patches until the best PSNR value is attained. Then the diffusion model is modified; instead of the gradient value, we use the inverse difference moment (IDM), which is a robust feature in determining the amount of local intensity variation in the presence of noise. Experiments with benchmark images and various noise levels show that the designed LFAD outperforms advanced diffusionbased denoising methods, and it is competitive with state-of-the-art block-transformed techniques; block and ring artifacts inherent to transform-based methods are reduced while PSNR levels are comparable

Simulating rhizosphere structure alterations using finite element calculations

The rhizosphere is the thin layer of soil that surrounds the roots playing a critical role as an environmental interface that controls water, nutrient and solute transport from the soil to the biosphere. Despite its importance, relatively little is known about the processes of mechanical rhizosphere formation and alteration as well as its impact on rhizosphere hydraulic properties in highly structured soils as for example seed beds. In this study, we used synchrotron X-ray microtomography (XMT) and finite element calculations to explore rhizosphere alterations due to a radially expanding root and its influence on rhizosphere hydraulic properties. XMT images from beds of aggregates containing plant roots were used as templates for creating finite element meshes of structured soil surrounding the root. Rhizosphere deformation was then simulated by virtual root growth, i.e. radial expansion of a cylindrical body within a bed of elasto-plastic aggregates. For various load steps, water flow through the deformed rhizosphere to the “root” surface was calculated. Finally, XMT observed structure alterations around real roots were compared to alterations simulated by finite element calculations. Mechanical simulations show that “root” expansion within a bed of aggregates can increase inter-aggregate contact area, whereas interaggregate porosity decreases. Hydraulic simulations show an increase in partially saturated hydraulic conductivity of the rhizosphere with increasing interaggregate contact area; however, in this case saturated hydraulic conductivity decreases because of a decrease in inter-aggregate pore space. For a loose initial aggregate packing, as used in this study, inter-aggregate contact area controls partially saturated hydraulic conductivity of the rhizosphere. With increasing degree of rhizosphere compaction, however, the influence of inter-aggregate contact area on partially saturated hydraulic conductivitydecreased and the hydraulic conductivity of the aggregate matrix became increasingly important. In agreement with observations from XMT images, mechanical simulations also show that root-induced rhizosphere compaction occurs primarily within a shell around the root with a shell thickness of one to two root radii. Although mechanical and hydraulic simulations are limited to 2D at this point, they provide some quantitative insight of how plant rootsmechanically alter the surrounding soil and in particular its hydraulic conductivity