301 research outputs found
Detection of curved lines with B-COSFIRE filters: A case study on crack delineation
The detection of curvilinear structures is an important step for various
computer vision applications, ranging from medical image analysis for
segmentation of blood vessels, to remote sensing for the identification of
roads and rivers, and to biometrics and robotics, among others. %The visual
system of the brain has remarkable abilities to detect curvilinear structures
in noisy images. This is a nontrivial task especially for the detection of thin
or incomplete curvilinear structures surrounded with noise. We propose a
general purpose curvilinear structure detector that uses the brain-inspired
trainable B-COSFIRE filters. It consists of four main steps, namely nonlinear
filtering with B-COSFIRE, thinning with non-maximum suppression, hysteresis
thresholding and morphological closing. We demonstrate its effectiveness on a
data set of noisy images with cracked pavements, where we achieve
state-of-the-art results (F-measure=0.865). The proposed method can be employed
in any computer vision methodology that requires the delineation of curvilinear
and elongated structures.Comment: Accepted at Computer Analysis of Images and Patterns (CAIP) 201
Curvilinear object segmentation in medical images based on ODoS filter and deep learning network
Automatic segmentation of curvilinear objects in medical images plays an
important role in the diagnosis and evaluation of human diseases, yet it is a
challenging uncertainty in the complex segmentation tasks due to different
issues such as various image appearances, low contrast between curvilinear
objects and their surrounding backgrounds, thin and uneven curvilinear
structures, and improper background illumination conditions. To overcome these
challenges, we present a unique curvilinear structure segmentation framework
based on an oriented derivative of stick (ODoS) filter and a deep learning
network for curvilinear object segmentation in medical images. Currently, a
large number of deep learning models emphasize developing deep architectures
and ignore capturing the structural features of curvilinear objects, which may
lead to unsatisfactory results. Consequently, a new approach that incorporates
an ODoS filter as part of a deep learning network is presented to improve the
spatial attention of curvilinear objects. Specifically, the input image is
transfered into four-channel image constructed by the ODoS filter. In which,
the original image is considered the principal part to describe various image
appearance and complex background illumination conditions, a multi-step
strategy is used to enhance the contrast between curvilinear objects and their
surrounding backgrounds, and a vector field is applied to discriminate thin and
uneven curvilinear structures. Subsequently, a deep learning framework is
employed to extract various structural features for curvilinear object
segmentation in medical images. The performance of the computational model is
validated in experiments conducted on the publicly available DRIVE, STARE and
CHASEDB1 datasets. The experimental results indicate that the presented model
yields surprising results compared with those of some state-of-the-art methods.Comment: 20 pages, 8 figure
Delineation of line patterns in images using B-COSFIRE filters
Delineation of line patterns in images is a basic step required in various
applications such as blood vessel detection in medical images, segmentation of
rivers or roads in aerial images, detection of cracks in walls or pavements,
etc. In this paper we present trainable B-COSFIRE filters, which are a model of
some neurons in area V1 of the primary visual cortex, and apply it to the
delineation of line patterns in different kinds of images. B-COSFIRE filters
are trainable as their selectivity is determined in an automatic configuration
process given a prototype pattern of interest. They are configurable to detect
any preferred line structure (e.g. segments, corners, cross-overs, etc.), so
usable for automatic data representation learning. We carried out experiments
on two data sets, namely a line-network data set from INRIA and a data set of
retinal fundus images named IOSTAR. The results that we achieved confirm the
robustness of the proposed approach and its effectiveness in the delineation of
line structures in different kinds of images.Comment: International Work Conference on Bioinspired Intelligence, July
10-13, 201
Curvilinear Structure Enhancement in Biomedical Images
Curvilinear structures can appear in many different areas and at a variety of scales. They can be axons and dendrites in the brain, blood vessels in the fundus, streets, rivers or fractures in buildings, and others. So, it is essential to study curvilinear structures in many fields such as neuroscience, biology, and cartography regarding image processing.
Image processing is an important field for the help to aid in biomedical imaging especially the diagnosing the disease. Image enhancement is the early step of image analysis.
In this thesis, I focus on the research, development, implementation, and validation of 2D and 3D curvilinear structure enhancement methods, recently established. The proposed methods are based on phase congruency, mathematical morphology, and tensor representation concepts.
First, I have introduced a 3D contrast independent phase congruency-based enhancement approach. The obtained results demonstrate the proposed approach is robust against the contrast variations in 3D biomedical images.
Second, I have proposed a new mathematical morphology-based approach called the bowler-hat transform. In this approach, I have combined the mathematical morphology with a local tensor representation of curvilinear structures in images.
The bowler-hat transform is shown to give better results than comparison methods on challenging data such as retinal/fundus images. The bowler-hat transform is shown to give better results than comparison methods on challenging data such as retinal/fundus images. Especially the proposed method is quite successful while enhancing of curvilinear structures at junctions.
Finally, I have extended the bowler-hat approach to the 3D version to prove the applicability, reliability, and ability of it in 3D
Neuropathy Classification of Corneal Nerve Images Using Artificial Intelligence
Nerve variations in the human cornea have been associated with alterations in
the neuropathy state of a patient suffering from chronic diseases. For some diseases,
such as diabetes, detection of neuropathy prior to visible symptoms is important,
whereas for others, such as multiple sclerosis, early prediction of disease worsening is
crucial. As current methods fail to provide early diagnosis of neuropathy, in vivo
corneal confocal microscopy enables very early insight into the nerve damage by
illuminating and magnifying the human cornea. This non-invasive method captures a
sequence of images from the corneal sub-basal nerve plexus. Current practices of
manual nerve tracing and classification impede the advancement of medical research in
this domain. Since corneal nerve analysis for neuropathy is in its initial stages, there is
a dire need for process automation.
To address this limitation, we seek to automate the two stages of this process:
nerve segmentation and neuropathy classification of images. For nerve segmentation,
we compare the performance of two existing solutions on multiple datasets to select the
appropriate method and proceed to the classification stage. Consequently, we approach
neuropathy classification of the images through artificial intelligence using Adaptive
Neuro-Fuzzy Inference System, Support Vector Machines, Naïve Bayes and k-nearest
neighbors. We further compare the performance of machine learning classifiers with
deep learning. We ascertained that nerve segmentation using convolutional neural networks provided a significant improvement in sensitivity and false negative rate by
at least 5% over the state-of-the-art software. For classification, ANFIS yielded the best
classification accuracy of 93.7% compared to other classifiers. Furthermore, for this
problem, machine learning approaches performed better in terms of classification
accuracy than deep learning
Automatic segmentation and classification methods using optical coherence tomography angiography (Octa): A review and handbook
Optical coherence tomography angiography (OCTA) is a promising technology for the non-invasive imaging of vasculature. Many studies in literature present automated algorithms to quantify OCTA images, but there is a lack of a review on the most common methods and their comparison considering multiple clinical applications (e.g., ophthalmology and dermatology). Here, we aim to provide readers with a useful review and handbook for automatic segmentation and classification methods using OCTA images, presenting a comparison of techniques found in the literature based on the adopted segmentation or classification method and on the clinical application. Another goal of this study is to provide insight into the direction of research in automated OCTA image analysis, especially in the current era of deep learning
OMSN and FAROS: OCTA Microstructure Segmentation Network and Fully Annotated Retinal OCTA Segmentation Dataset
The lack of efficient segmentation methods and fully-labeled datasets limits
the comprehensive assessment of optical coherence tomography angiography (OCTA)
microstructures like retinal vessel network (RVN) and foveal avascular zone
(FAZ), which are of great value in ophthalmic and systematic diseases
evaluation. Here, we introduce an innovative OCTA microstructure segmentation
network (OMSN) by combining an encoder-decoder-based architecture with
multi-scale skip connections and the split-attention-based residual network
ResNeSt, paying specific attention to OCTA microstructural features while
facilitating better model convergence and feature representations. The proposed
OMSN achieves excellent single/multi-task performances for RVN or/and FAZ
segmentation. Especially, the evaluation metrics on multi-task models
outperform single-task models on the same dataset. On this basis, a fully
annotated retinal OCTA segmentation (FAROS) dataset is constructed
semi-automatically, filling the vacancy of a pixel-level fully-labeled OCTA
dataset. OMSN multi-task segmentation model retrained with FAROS further
certifies its outstanding accuracy for simultaneous RVN and FAZ segmentation.Comment: 10 pages, 6 figures, submitted to IEEE Transactions on Medical
Imaging (TMI
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