Abstract
Automated and accurate segmentation of retinal vessels in fundus images is an important step for screening and diagnosing various ophthalmologic diseases. However, many factors, including the variations of vessels in color, shape and size, make this task become an intricate challenge. One kind of the most popular methods for vessel segmentation is U-Net based methods. However, in the U-Net based methods, the size of the convolution kernels is generally fixed. As a result, the receptive field for an individual convolution operation is single, which is not conducive to the segmentation of retinal vessels with various thicknesses. To overcome this problem, in this paper, we employed self-calibrated convolutions to replace the traditional convolutions for the U-Net, which can make the U-Net learn discriminative representations from different receptive fields. Besides, we proposed an improved spatial attention module, instead of using traditional convolutions, to connect the encoding part and decoding part of the U-Net, which can improve the ability of the U-Net to detect thin vessels. The proposed method has been tested on Digital Retinal Images for Vessel Extraction (DRIVE) database and Child Heart and Health Study in England Database (CHASE DB1). The metrics used to evaluate the performance of the proposed method are accuracy (ACC), sensitivity (SE), specificity (SP), F1-score (F1) and the area under the receiver operating characteristic curve (AUC). The ACC, SE, SP, F1 and AUC obtained by the proposed method are 0.9680, 0.8036, 0.9840, 0.8138 and 0.9840 respectively on DRIVE database, and 0.9756, 0.8118, 0.9867, 0.8068 and 0.9888 respectively on CHASE DB1, which are better than those obtained by the traditional U-Net (the ACC, SE, SP, F1 and AUC obtained by U-Net are 0.9646, 0.7895, 0.9814, 0.7963 and 0.9791 respectively on DRIVE database, and 0.9733, 0.7817, 0.9862, 0.7870 and 0.9810 respectively on CHASE DB1). The experimental results indicate that the proposed modifications in the U-Net are effective for vessel segmentation.
Similar content being viewed by others
References
Alom MZ, Yakopcic C, Hasan M, Taha TM, Asari VK (2019) Recurrent residual U-Net for medical image segmentation. J Med Imaging 6(1):014,006
Azzopardi G, Strisciuglio N, Vento M, Petkov N (2015) Trainable cosfire filters for vessel delineation with application to retinal images. Med Image Anal 19(1):46–57
Fan Z, Lu J, Wei C, Huang H, Cai X, Chen X (2018) A hierarchical image matting model for blood vessel segmentation in fundus images. IEEE Trans Image Process 28(5):2367–2377
Fazlali HR, Karimi N, Soroushmehr SR, Shirani S, Nallamothu BK, Ward KR, Samavi S, Najarian K (2018) Vessel segmentation and catheter detection in x-ray angiograms using superpixels. Med Biol Eng Comput 56(9):1515–1530
Fraz MM, Remagnino P, Hoppe A, Uyyanonvara B, Rudnicka AR, Owen CG, Barman SA (2012) Blood vessel segmentation methodologies in retinal images–a survey. Comput Methods Programs Biomed 108(1):407–433
Fraz MM, Remagnino P, Hoppe A, Uyyanonvara B, Rudnicka AR, Owen CG, Barman SA (2012) An ensemble classification-based approach applied to retinal blood vessel segmentation. IEEE Trans Biomed Eng 59(9):2538–2548
Guo C, Szemenyei M, Yi Y, Wang W, Chen B, Fan C (2020) SA-UNet: Spatial attention U-Net for retinal vessel segmentation. arXiv:2004.03696
Guo X, Xiao R, Zhang T, Chen C, Wang J, Wang Z (2020) A novel method to model hepatic vascular network using vessel segmentation, thinning, and completion. Med Biol Eng Comput 1–16
Hamamoto Y, Uchimura S, Watanabe M, Yasuda T, Mitani Y, Tomita S (1998) A Gabor filter-based method for recognizing handwritten numerals. Pattern Recogn 31(4):395–400
Lam BS, Gao Y, Liew AWC (2010) General retinal vessel segmentation using regularization-based multiconcavity modeling. IEEE Trans Med Imaging 29(7):1369–1381
Lecun Y, Bengio Y, Hinton GE (2015) Deep learning. Nature 521(7553):436–444
Lecun Y, Bottou L, Bengio Y, Haffner P (1998) Gradient-based learning applied to document recognition. Proc IEEE 86(11):2278–2324
Li Q, Feng B, Xie L, Liang P, Zhang H, Wang T (2015) A cross-modality learning approach for vessel segmentation in retinal images. IEEE Trans Med Imaging 35(1):109–118
Li X, Wang L, Sung E (2008) AdaBoost with SVM-based component classifiers. Eng Appl Artif Intel 21(5):785–795
Liskowski P, Krawiec K (2016) Segmenting retinal blood vessels with deep neural networks. IEEE Trans Med Imaging 35(11):2369–2380
Liu I, Sun Y (1993) Recursive tracking of vascular networks in angiograms based on the detection-deletion scheme. IEEE Trans Med Imaging 12(2):334–341
Liu JJ, Hou Q, Cheng MM, Wang C, Feng J (2020) Improving convolutional networks with self-calibrated convolutions. In: Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pp 10,096–10,105
Mendonca AM, Campilho A (2006) Segmentation of retinal blood vessels by combining the detection of centerlines and morphological reconstruction. IEEE Trans Med Imaging 25(9):1200–1213
Mou L, Zhao Y, Fu H, Liu Y, Cheng J, Zheng Y, Su P, Yang J, Chen L, Frangi AF et al (2021) CS2-Net: Deep learning segmentation of curvilinear structures in medical imaging. Med Image Anal 67:101,874
Nguyen V, Blumenstein M (2011) An application of the 2D gaussian filter for enhancing feature extraction in off-line signature verification. In: 2011 international conference on document analysis and recognition. IEEE, pp 339–343
Ricci E, Perfetti R (2007) Retinal blood vessel segmentation using line operators and support vector classification. IEEE Trans Med Imaging 26(10):1357–1365
Ronneberger O, Fischer P, Brox T (2015) U-Net: Convolutional networks for biomedical image segmentation. In: International Conference on Medical image computing and computer-assisted intervention. Springer, pp 234–241
Roychowdhury S, Koozekanani DD, Parhi KK (2014) Blood vessel segmentation of fundus images by major vessel extraction and subimage classification. IEEE J Biomed Health Inf 19(3):1118–1128
Salem SA, Salem NM, Nandi AK (2007) Segmentation of retinal blood vessels using a novel clustering algorithm (RACAL) with a partial supervision strategy. Med Biol Eng Comput 45(3):261–273
Staal J, Abràmoff MD, Niemeijer M, Viergever MA, Van Ginneken B (2004) Ridge-based vessel segmentation in color images of the retina. IEEE Trans Med Imaging 23(4):501–509
Wang B, Qiu S, He H (2019) Dual encoding U-Net for retinal vessel segmentation. In: International conference on medical image computing and computer-assisted intervention. Springer, pp 84–92
Wang B, Wang S, Qiu S, Wei W, Wang H, He H (2020) CSU-Net: a context spatial u-net for accurate blood vessel segmentation in fundus images. IEEE J Biomed Health Inform 25(4):1128–1138
Wang W, Wang W, Hu Z (2019) Segmenting retinal vessels with revised top-bottom-hat transformation and flattening of minimum circumscribed ellipse. Med Biol Eng Comput 57(7):1481–1496
Wei J, Zhu G, Fan Z, Liu J, Rong Y, Mo J, Li W, Chen X (2022) Genetic U-Net: automatically designed deep networks for retinal vessel segmentation using a genetic algorithm. IEEE Trans Med Imaging 41(2):292–307
Woo S, Park J, Lee JY, Kweon IS (2018) CBAM: Convolutional block attention module. In: Proceedings of the European conference on computer vision (ECCV), pp 3–19
Wu Y, Xia Y, Song Y, Zhang Y, Cai W (2018) Multiscale network followed network model for retinal vessel segmentation. In: International conference on medical image computing and computer-assisted intervention. Springer, pp 119–126
Zhao Y, Rada L, Chen K, Harding SP, Zheng Y (2015) Automated vessel segmentation using infinite perimeter active contour model with hybrid region information with application to retinal images. IEEE Trans Med Imaging 34(9):1797–1807
Funding
This work was supported in part by the National Key R&D Program of China under grant 2021ZD0111502, in part by the Science and Technology Planning Project of Guangdong Province of China under grant 180917144960530, in part by the Project of Educational Commission of Guangdong Province of China under grant 2017KZDXM032, in part by Science Research Startup Foundation of Shantou University NTF20021, in part by the State Key Lab of Digital Manufacturing Equipment and Technology under grant DMETKF2019020, in part by the Project of Robot Automatic Design Platform combining Multi-Objective Evolutionary Computation and Deep Neural Network under grant 2019A050519008, in part by the Guangdong Natural Science Foundation under grant 2022A1515011396.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Rong, Y., Xiong, Y., Li, C. et al. Segmentation of retinal vessels in fundus images based on U-Net with self-calibrated convolutions and spatial attention modules. Med Biol Eng Comput 61, 1745–1755 (2023). https://doi.org/10.1007/s11517-023-02806-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11517-023-02806-1