Convolutional nets for reconstructing neural circuits from brain images acquired by serial section electron microscopy

Neural circuits can be reconstructed from brain images acquired by serial section electron microscopy. Image analysis has been performed by manual labor for half a century, and efforts at automation date back almost as far. Convolutional nets were first applied to neuronal boundary detection a dozen years ago, and have now achieved impressive accuracy on clean images. Robust handling of image defects is a major outstanding challenge. Convolutional nets are also being employed for other tasks in neural circuit reconstruction: finding synapses and identifying synaptic partners, extending or pruning neuronal reconstructions, and aligning serial section images to create a 3D image stack. Computational systems are being engineered to handle petavoxel images of cubic millimeter brain volumes

Taramalı electron mikroskobu görüntülerinde mitokondrilerin otomatik olarak bölütlenmesi

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

Segmentation in large-scale cellular electron microscopy with deep learning: A literature survey

Electron microscopy (EM) enables high-resolution imaging of tissues and cells based on 2D and 3D imaging techniques. Due to the laborious and time-consuming nature of manual segmentation of large-scale EM datasets, automated segmentation approaches are crucial. This review focuses on the progress of deep learning-based segmentation techniques in large-scale cellular EM throughout the last six years, during which significant progress has been made in both semantic and instance segmentation. A detailed account is given for the key datasets that contributed to the proliferation of deep learning in 2D and 3D EM segmentation. The review covers supervised, unsupervised, and self-supervised learning methods and examines how these algorithms were adapted to the task of segmenting cellular and sub-cellular structures in EM images. The special challenges posed by such images, like heterogeneity and spatial complexity, and the network architectures that overcame some of them are described. Moreover, an overview of the evaluation measures used to benchmark EM datasets in various segmentation tasks is provided. Finally, an outlook of current trends and future prospects of EM segmentation is given, especially with large-scale models and unlabeled images to learn generic features across EM datasets

Semantic segmentation of HeLa cells: An objective comparison between one traditional algorithm and four deep-learning architectures

The quantitative study of cell morphology is of great importance as the structure and condition of cells and their structures can be related to conditions of health or disease. The first step towards that, is the accurate segmentation of cell structures. In this work, we compare five approaches, one traditional and four deep-learning, for the semantic segmentation of the nuclear envelope of cervical cancer cells commonly known as HeLa cells. Images of a HeLa cancer cell were semantically segmented with one traditional image-processing algorithm and four three deep learning architectures: VGG16, ResNet18, Inception-ResNet-v2, and U-Net. Three hundred slices, each 2000 × 2000 pixels, of a HeLa Cell were acquired with Serial Block Face Scanning Electron Microscopy. The first three deep learning architectures were pre-trained with ImageNet and then fine-tuned with transfer learning. The U-Net architecture was trained from scratch with 36, 000 training images and labels of size 128 × 128. The image-processing algorithm followed a pipeline of several traditional steps like edge detection, dilation and morphological operators. The algorithms were compared by measuring pixel-based segmentation accuracy and Jaccard index against a labelled ground truth. The results indicated a superior performance of the traditional algorithm (Accuracy = 99%, Jaccard = 93%) over the deep learning architectures: VGG16 (93%, 90%), ResNet18 (94%, 88%), Inception-ResNet-v2 (94%, 89%), and U-Net (92%, 56%)