Segmentation of retinal image vessels based on fully convolutional network with depthwise separable convolution and channel weighting / 生物医学工程学杂志

Diseases such as diabetes and hypertension can lead to change the shape of the retinal blood vessels. Segmentation of fundus images is a key step in the process of quantitative analysis of the disease, which is instructive in the analysis and diagnosis of clinical diseases. In this paper, a method for the segmentation of retinal image vessels based on fully convolutional network (FCN) with depthwise separable convolution and channel weighting is presented. Firstly, CLAHE and Gamma correction of the green channel of the fundus image are used to enhance the contrast. Then, in order to adapt to network training, the enhanced image is divided into patches to expand the data. Finally, the depthwise separable convolution instead of the standard convolution method is used to increase the network width. Meanwhile, the channel weighting module is introduced to explicitly model the relationship between the characteristic channels in order to improve the distinguishability of the features. The combination of them is applied to the FCN and the results of expert manual identification are used to supervise the experiment on the DRIVE database. The results show that the segmentation accuracy of the proposed method in DRIVE database reached 0.963 0 and AUC reached 0.983 1. The segmentation accuracy in STARE database reached 0.962 0 and AUC achieved 0.983 0. To some extent, the proposed method has better feature resolution and better segmentation performance.

Application of OCT angiography in ophthalmology / 国际眼科杂志(Guoji Yanke Zazhi)

Optical coherence tomography angiography (OCTA) is a new technology of angiography in recent years.In addition to the advantages of traditional OCT,it can observe blood flow in different retinal and choroidal segmentation slab.By using the pseudo-color,abnormal vascular structure can be distinguished from normal vascular structure of the retina.Dye injection is not needed with OCTA,which is different from fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA).OCTA provides more and more accurate blood flow information.However,like other biometric technology,OCTA has its limitations and shortcomings.This review will analyze and summarize the operating principle of OCTA,its application in ophthalmology,as well as its advantages and limitations.