17 research outputs found

    Automatic Mitochondria Segmentation for EM Data Using a 3D Supervised Convolutional Network

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    Recent studies have supported the relation between mitochondrial functions and degenerative disorders related to ageing, such as Alzheimer's and Parkinson's diseases. Since these studies have exposed the need for detailed and high-resolution analysis of physical alterations in mitochondria, it is necessary to be able to perform segmentation and 3D reconstruction of mitochondria. However, due to the variety of mitochondrial structures, automated mitochondria segmentation and reconstruction in electron microscopy (EM) images have proven to be a difficult and challenging task. This paper puts forward an effective and automated pipeline based on deep learning to realize mitochondria segmentation in different EM images. The proposed pipeline consists of three parts: (1) utilizing image registration and histogram equalization as image pre-processing steps to maintain the consistency of the dataset; (2) proposing an effective approach for 3D mitochondria segmentation based on a volumetric, residual convolutional and deeply supervised network; and (3) employing a 3D connection method to obtain the relationship of mitochondria and displaying the 3D reconstruction results. To our knowledge, we are the first researchers to utilize a 3D fully residual convolutional network with a deeply supervised strategy to improve the accuracy of mitochondria segmentation. The experimental results on anisotropic and isotropic EM volumes demonstrate the effectiveness of our method, and the Jaccard index of our segmentation (91.8% in anisotropy, 90.0% in isotropy) and F1 score of detection (92.2% in anisotropy, 90.9% in isotropy) suggest that our approach achieved state-of-the-art results. Our fully automated pipeline contributes to the development of neuroscience by providing neurologists with a rapid approach for obtaining rich mitochondria statistics and helping them elucidate the mechanism and function of mitochondria

    Taramalı electron mikroskobu görüntülerinde mitokondrilerin otomatik olarak bölütlenmesi

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    Many studies have shown that shape of mitochondria indicates the occurrence of diseases. Scanning Electron Microscopy (SEM) enables to obtain image of internal structures of the cell and mitochondria. Automatic segmentation of mitochondria contributes to the decision of diseases by specialists. There is limited study about automatic segmentation of mitochondria in Serial Block-Face Scanning Electron Microscopy (SFBSEM) images. SBFSEM imaging technique provides full automation, well registered images, less time and less effort for data acquisition. Therefore, SBFSEM imaging technique is selected for this study. Recently, deep learning methods have been implemented for image processing of SEM datasets. However, due to requirement of huge datasets, much effort and powerful computers for preparing testing and training data, energy based model is implemented for this study. The algorithms used in this thesis are primarily the algorithms developed by Tasel et al for mitochondria segmentation in TEM images. The method includes preprocessing, ridge detection, energy mapping, curve fitting, snake-based shape extraction, validation and post-processing steps. In this thesis, these algorithms are adapted and refined for SBFSEM images to obtain optimum performance. Evaluations are made by using Dice Similarity Coefficient (DSC), precision, recall and F-Score metrics.Birçok çalışma mitokondri ve kristaların şeklinin hastalıkların oluşumunu belirttiğini göstermektedir. Taramalı Elektron Mikroskobu (SEM), hücrenin iç yapılarının ve mitokondrilerin görüntülerinin elde edilmesini sağlar. Mitokondrilerin otomatik bölütlenmesi uzmanlar tarafından hastalıkların karar verilmesine katkı sağlar. Seri Blok-Yüz Taramalı Elektron Mikroskobu (SFBSEM) görüntülerinde mitokondrinin otomatik segmentasyonu hakkında sınırlı çalışma vardır. SBFSEM görüntüleme tekniği, tam otomasyon, iyi kaydedilmiş görüntüler, veri elde etmek için daha az zaman ve daha az çaba sağlar. Bu nedenle, bu çalışma için SBFSEM görüntüleme tekniği seçilmiştir. Son zamanlarda, derin ögrenme yöntemleri SEM veri setlerinin görüntü işlemesi için uygulanmaktadır. Ancak, büyük veri setlerinin, fazla çabanın ve test ve eğitim verilerinin hazırlanması için güçlü bilgisayarların gerekliliğinden bu çalışma için enerji tabanlı model uygulanmaktadır. Bu tezde kullanılan algoritmalar öncelikle TEM görüntülerinde mitokondri bölütlenmesi için Taşel ve arkadaşları tarafından geliştirilen algoritmalardır. Yöntem, ön işleme, sırt algılama, enerji haritalama, eğri uyumlandırma, yılan temelli şekil çıkarma, doğrulama ve son işlem adımlarını içerir. Bu tezde, bu algoritmalar optimum performans elde etmek için SBFSEM görüntüleri için uyarlanmış ve yeniden düzenlenmiştir. Değerlendirmeler Dice Benzerlik Katsayısı(DSC), kesinlik, hatırlama ve F-Skoru metrikleri kullanılarak yapılır.M.S. - Master of Scienc

    Methods for the acquisition and analysis of volume electron microscopy data

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    Computational methods in Connectomics

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    Towards Fast and High-quality Biomedical Image Reconstruction

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    Department of Computer Science and EngineeringReconstruction is an important module in the image analysis pipeline with purposes of isolating the majority of meaningful information that hidden inside the acquired data. The term ???reconstruction??? can be understood and subdivided in several specific tasks in different modalities. For example, in biomedical imaging, such as Computed Tomography (CT), Magnetic Resonance Image (MRI), that term stands for the transformation from the, possibly fully or under-sampled, spectral domains (sinogram for CT and k-space for MRI) to the visible image domains. Or, in connectomics, people usually refer it to segmentation (reconstructing the semantic contact between neuronal connections) or denoising (reconstructing the clean image). In this dissertation research, I will describe a set of my contributed algorithms from conventional to state-of-the-art deep learning methods, with a transition at the data-driven dictionary learning approaches that tackle the reconstruction problems in various image analysis tasks.clos

    Computational methods in Connectomics

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    A model-based method for 3D reconstruction of cerebellar parallel fibres from high-resolution electron microscope images

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    In order to understand how the brain works, we need to understand how its neural circuits process information. Electron microscopy remains the only imaging technique capable of providing sufficient resolution to reconstruct the dense connectivity between all neurons in a circuit. Automated electron microscopy techniques are approaching the point where usefully large circuits might be successfully imaged, but the development of automated reconstruction techniques lags far behind. No fully-automated reconstruction technique currently produces acceptably accurate reconstructions, and semi-automated approaches currently require an extreme amount of manual effort. This reconstruction bottleneck places severe limits on the size of neural circuits that can be reconstructed. Improved automated reconstruction techniques are therefore highly desired and under active development. The human brain contains ~86 billion neurons and ~80% of these are located in the cerebellum. Of these cerebellar neurons, the vast majority are granule cells. The axons of these granule cells are called parallel fibres and tend to be oriented in approximately the same direction, making 2+1D reconstruction approaches feasible. In this work we focus on the problem of reconstructing these parallel fibres and make four main contributions: (1) a model-based algorithm for reconstructing 2D parallel fibre cross-sections that achieves state of the art 2D reconstruction performance; (2) a fully-automated algorithm for reconstructing 3D parallel fibres that achieves state of the art 3D reconstruction performance; (3) a semi-automated approach for reconstructing 3D parallel fibres that significantly improves reconstruction accuracy compared to our fully-automated approach while requiring ~40 times less labelling effort than a purely manual reconstruction; (4) a "gold standard" ground truth data set for the molecular layer of the mouse cerebellum that will provide a valuable reference for the development and benchmarking of reconstruction algorithms

    Connectomic analysis of the input to the principal cells of the mammalian cerebral cortex

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