In recent years, deep learning has found widespread applications in tasks such as segmentation and classification. Fine-tuning hyperparameters is crucial to improve performance, with the learning rate being a key para...
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In recent years, deep learning has found widespread applications in tasks such as segmentation and classification. Fine-tuning hyperparameters is crucial to improve performance, with the learning rate being a key parameter. Various methods, including adaptive learning rates, learning rate scheduling, and cyclical learning rates, have been used to optimize learning rates. Cyclical learning rates offer significant benefits with minimal computational cost, as seen in previous research. This study introduces a novel approach to tuning the cyclical learning rate, which incorporates the exponential moving average. These methods are applied to the BraTS 2021 dataset for segmentation tasks, resulting in superior performance compared to the previous approach. Our proposed method reduces the epochs required to reach convergence by 19 and 54 epochs for U-Net anddense U-net, respectively. For Res U-net, the epoch needed to convergence is 10 epochs more. However, the proposed method produces lower loss values with 0.707, 0.657, and 0.665 compared to the previous method with 0.712, 0.685, and 0.725 for U-net, Res U-net, anddense U-net, respectively.
We compare two conceptually different stochastic microstructure models, i.e., a graph-based model and a pluri-Gaussian model, that have been introduced to model the transport properties of three-phase microstructures ...
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We compare two conceptually different stochastic microstructure models, i.e., a graph-based model and a pluri-Gaussian model, that have been introduced to model the transport properties of three-phase microstructures occurring, e.g., in solid oxide fuel cell electrodes. Besides comparing both models, we present new results regarding the relationship between model parameters and certain microstructure characteristics. In particular, an analytical expression is obtained for the expected length of triple phase boundary per unit volume in the pluri-Gaussian model. As a case study, we consider 3d image data which show a representative cutout of a solid oxide fuel cell anode obtained by FIB-SEM tomography. The two models are fitted to imagedata and compared in terms of morphological characteristics (like mean geodesic tortuosity and constrictivity) as well as in terms of effective transport properties. The Stokes flow in the pore phase and effective conductivities in the solid phases are computed numerically for realizations of the two models as well as for the 3d image data using Fourier methods. The local and effective physical responses of the model realizations are compared to those obtained from 3d image data. Finally, we assess the accuracy of the two methods to predict permeability as well as electronic and ionic conductivities of the anode.
Generative Adversarial Networks (GANs) have gained significant attention in several computer vision tasks for generating high-quality synthetic data. Various medical applications including diagnostic imaging and radia...
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Generative Adversarial Networks (GANs) have gained significant attention in several computer vision tasks for generating high-quality synthetic data. Various medical applications including diagnostic imaging and radiation therapy can benefit greatly from synthetic data generation due to data scarcity in the domain. However, medical imagedata is typically kept in 3d space, and generative models suffer from the curse of dimensionality issues in generating such synthetic data. In this paper, we investigate the potential of GANs for generating connected3d volumes. We propose an improved version of 3d alpha-GAN by incorporating various architectural enhancements. On a synthetic dataset of connected3d spheres and ellipsoids, our model can generate fully connected3d shapes with similar geometrical characteristics to that of training data. We also show that our 3d GAN model can successfully generate high-quality 3d tumor volumes and associated treatment specifications (e.g., isocenter locations). Similar moment invariants to the training data as well as fully connected3d shapes confirm that improved3d alpha-GAN implicitly learns the training datadistribution, and generates realistic-looking samples. The capability of improved3d alpha-GAN makes it a valuable source for generating synthetic medical imagedata that can help future research in this domain.
We determine optimal designs for some regression models which are frequently used for describing three-dimensional shapes. These models are based on a Fourier expansion of a function defined on the unit sphere in term...
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We determine optimal designs for some regression models which are frequently used for describing three-dimensional shapes. These models are based on a Fourier expansion of a function defined on the unit sphere in terms of spherical harmonic basis functions. In particular, it is demonstrated that the uniform distribution on the sphere is optimal with respect to all Phi(p) criteria proposed by Kiefer in 1974 and also optimal with respect to a criterion which maximizes a p mean of the r smallest eigenvalues of the variance-covariance matrix. This criterion is related to principal component analysis, which is the common tool for analyzing this type of imagedata. Moreover, discrete designs on the sphere are derived, which yield the same information matrix in the spherical harmonic regression model as the uniform distribution and are therefore directly implementable in practice. It is demonstrated that the new designs are substantially more efficient than the commonly useddesigns in three-dimensional shape analysis.
Cell segmentation is a central task in biomedical image analysis. We introduce a 3ddeep neural network for 3d cell nuclei segmentation that performs multi-task learning to generate different representations from 3d m...
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ISBN:
(纸本)9798350313345;9798350313338
Cell segmentation is a central task in biomedical image analysis. We introduce a 3ddeep neural network for 3d cell nuclei segmentation that performs multi-task learning to generate different representations from 3d microscopy images. The network exploits information about cell regions, cell contours, and cell distances. It consists of a 3d Residual U-Net with Squeeze-and-Excitation operations and is trained with a recently introduced loss function that suppresses image regions away from cell borders. To improve cell splitting, we propose a novel representation named signed Instance distance. Cell instance segmentation is achieved by combining the learned representations to determine cell seeds for a watershed algorithm. We also introduce a 2d version of the network. The method was applied to large-scale 3d micro-CT and3d electron microscopy datasets from NucMM as well as to 2d fluorescence and phase-contrast microscopy datasets from the Cell Tracking Challenge. For the 3ddatasets, the method achieves a large improvement compared to existing methods. For the 2ddatasets, the method yields the best segmentation accuracy out of 39 methods for one of the datasets.
Annulus manual segmentation is an important tool for the study of valve anatomy and physiology, for the four main valves of the heart (mitral, tricuspid, aortic and pulmonary). In this paper we review two traditional ...
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ISBN:
(纸本)9781424441242
Annulus manual segmentation is an important tool for the study of valve anatomy and physiology, for the four main valves of the heart (mitral, tricuspid, aortic and pulmonary). In this paper we review two traditional manual segmentation approaches: slice-by-slice and interpolating a sparse set of landmarks with a spline curve. We propose a new Spline Tool for the open source software platform Seg3d, that is fast and improves spatial coherence by providing visual feedback of the segmentation in real time. The Spline Tool was tested successfully on 14 rat hearts, on all four valves.
Automatic detection of particles in fluorescence microscopy images is crucial to analyze cellular processes. We introduce a novel deep learning method for 3d fluorescent particle detection. Instead of pixel-wise binar...
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ISBN:
(纸本)9781665429238
Automatic detection of particles in fluorescence microscopy images is crucial to analyze cellular processes. We introduce a novel deep learning method for 3d fluorescent particle detection. Instead of pixel-wise binary classification or direct coordinate regression, we perform image-to-image mapping based on regressing a density map. detections close to particles are rewarded in the network training, and highly nonlinear direct prediction of point coordinates is avoided. To focus on particles in comparison to backgroundimage points, we suggest using the adaptive wing loss. We also employ a weighted loss map to cope with the very strong imbalance between particle and backgroundimage points for 3dimages. We evaluated our approach using 3dimages of the Particle Tracking Challenge and real 3d fluorescence microscopy images of chromatin structures and interneurons. It turned out that our approach generally outperforms previous methods.
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