Hard Exudate Extraction from Fundus Images using Watershed Transform

Vasanthi Satyananda,K Karibasappa,K.V Narayanaswamy

doi:10.52549/ijeei.v7i3.775

Abstract

Diabetic Retinopathy is a medical condition which affects the eyes due to increased blood sugar levels. This is characterized by presence of exudates - deposits of lipids in the posterior pole of the retina. If this ailment is not treated in earlier stages these deposits can cause blurred vision or even permanent blindness. This paper concentrates on extraction of hard exudates and optic disc from the retinal images of eyes using Marker based Watershed approach, which uses the minima imposition method to create mask and marker. The varying contrast across all the images has been taken care by a non-linear equation. Once these bright objects have been extracted from fundus images, area estimation is performed to eliminate the optic disk, thus retaining only exudates. These images have been procured from publicly available databases. Though software systems are easy to install, they prove to be expensive in terms of time and cost; thus this method has also been implemented on FPGA for an on-chip solution. The precision and sensitivity for exudate extraction sans optic disk are found to be 92.4% and 83.78% respectively. Though other techniques exist which provide better accuracy, the method described in this paper is found to be hardware friendly in comparison with other proven methods. Few steps of the algorithm developed are implemented on FPGA to provide an embedded system approach to this work, considering the advantages of a hardware-software combination.

Highlights

Known as “Diabetes”, Diabetes mellitus is a medical malady caused due to non-typical levels of blood glucose level [1]
Though software systems are easy to install, they prove to be expensive in terms of time and cost; this method has been implemented on FPGA for an on-chip solution
If the optic disk lies in dark contrast area while the exudates lie in the brighter region of the image, the optic disk will never be identified and the largest exudate area will be wrongly considered as the optic disk and in turn will be eliminated as can be seen in Figure 12e and Figure 12f

Summary

Introduction

Known as “Diabetes”, Diabetes mellitus is a medical malady caused due to non-typical levels of blood glucose level [1]. Diabetic Retinopathy (abbreviated as DR) is one such medical abnormality where the blood vessels of the retina of the eyes become fragile and eventually disintegrate causing swelling or leakage of the blood vessel fibre ending [2]. This terminates the oxygen flow to retina causing the death of retinal tissues. The blood vessels can bloat and eventually leading to closure of the same, which is named as macular ischemia [5] This leads to deposits of fatty compounds and lipids in the retina, which are known as exudates.

Methods

Results

Conclusion