Multidim Syst Sign Process https://doi.org/10.1007/s11045-018-0561-9 Morphological operations with iterative rotation of structuring elements for segmentation of retinal vessel structures Soumyadeep Pal 1 · Saptarshi Chatterjee 1 · Debangshu Dey 1 · Sugata Munshi 1 Received: 30 June 2017 / Revised: 20 February 2018 / Accepted: 23 February 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract The development of computer aided diagnosis system has a great impact on early and accurate disease diagnosis. The segmentation of retinal blood vessels aids in identify- ing the alteration in vessel structure and hence helps to diagnose many diseases such as diabetic retinopathy, glaucoma, hypertension along with some cardiovascular diseases. In this research work, a method is presented for the segmentation of retinal vessel structure from retinal fundus images. 2D wavelet transform assisted morphological gradient operation based ‘Contrast Limited Adaptive Histogram Equalization’ technique has been introduced for the preprocessing of the low contrast fundus images. Morphological gray level hit-or-miss transform with multi-structuring element with varying orientation has been proposed for the separation of blood vessel from its background. Finally a hysteresis thresholding, guided by some morphological operations has been employed to obtain the binary image excluding other unwanted areas. The proposed methodology has been tested on DRIVE database and a maximum accuracy and an average accuracy of 95.65 and 94.31% respectively have been achieved. Keywords Computer aided diagnosis · Diabetic retinopathy · Hit-or-miss transform · Segmentation · Wavelet transform 1 Introduction The detection of retinal blood vessels from fundus imaging (Abràmoff et al. 2010) plays an important role in modern ophthalmology and clinical research. The vascular structure obtained from retinal fundus imaging leads to the diagnosis of various diseases. According to different studies (Hoover et al. 2000), the temporal changes in the width and the morphology of blood vessels are being considered as the primary symptom of glaucoma, diabetic retinopathy, B Saptarshi Chatterjee saptarshichatterjee2009@gmail.com 1 Electrical Engineering Department, Jadavpur University, Kolkata, India 123