Study of the noise level in the colour fundus images

Abstract

Diabetic Retinopathy (DR) causes vision loss insufficiency due to impediment rising from high sugar level conditions disturbing the retina. The Progression of DR occurs in the Foveal avascular zone (FAZ) due to loss of tiny blood vessels of capillary network. Due to image acquisition process of fundus camera, the colour retinal fundus image suffers from varying contrast and noise problems. To overcome varying contrast and noise problem in fundus image, the technique has been implemented. The technique is contained on the Retinex algorithm along with stationary wavelet transform. The technique has been applied on 36 high resolution fundus (HRF) image database contain the 18 bad quality images and 18 good quality images. The RETSWT (RETinex and Stationary Wavelet Transform) developed with introduces denoising techniques. Stationary wavelet transform is used as denoised technique. RETSWT achieved the average PSNR improvement of 2.39 db good quality images else it achieved the average PSNR improvement of 2.20 db in the bad quality images. The RETSWT image enhancement method potentially reduces the need of the invasive fluorescein angiogram in DR assessment.