{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T08:24:25Z","timestamp":1782289465118,"version":"3.54.5"},"reference-count":38,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2019,1,4]],"date-time":"2019-01-04T00:00:00Z","timestamp":1546560000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61672322"],"award-info":[{"award-number":["61672322"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Algorithms"],"abstract":"<jats:p>Diabetic retinopathy (DR) is a complication of diabetes and is known as visual impairment, and is diagnosed in various ethnicities of the working-age population worldwide. Fundus angiography is a widely applicable modality used by ophthalmologists and computerized applications to detect DR-based clinical features such as microaneurysms (MAs), hemorrhages (HEMs), and exudates (EXs) for early screening of DR. Fundus images are usually acquired using funduscopic cameras in varied light conditions and angles. Therefore, these images are prone to non-uniform illumination, poor contrast, transmission error, low brightness, and noise problems. This paper presents a novel and real-time mechanism of fundus image enhancement used for early grading of diabetic retinopathy, macular degeneration, retinal neoplasms, and choroid disruptions. The proposed system is based on two folds: (i) An RGB fundus image is initially taken and converted into a color appearance module (called lightness and denoted as J) of the CIECAM02 color space model to obtain image information in grayscale with bright light. Afterwards, in step (ii), the achieved J component is processed using a nonlinear contrast enhancement approach to improve the textural and color features of the fundus image without any further extraction steps. To test and evaluate the strength of the proposed technique, several performance and quality parameters\u2014namely peak signal-to-noise ratio (PSNR), contrast-to-noise ratio (CNR), entropy (content information), histograms (intensity variation), and a structure similarity index measure (SSIM)\u2014were applied to 1240 fundus images comprised of two publicly available datasets, DRIVE and MESSIDOR. It was determined from the experiments that the proposed enhancement procedure outperformed histogram-based approaches in terms of contrast, sharpness of fundus features, and brightness. This further revealed that it can be a suitable preprocessing tool for segmentation and classification of DR-related features algorithms.<\/jats:p>","DOI":"10.3390\/a12010014","type":"journal-article","created":{"date-parts":[[2019,1,4]],"date-time":"2019-01-04T11:34:26Z","timestamp":1546601666000},"page":"14","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":45,"title":["A Hybrid Proposed Fundus Image Enhancement Framework for Diabetic Retinopathy"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8542-7112","authenticated-orcid":false,"given":"Imran","family":"Qureshi","sequence":"first","affiliation":[{"name":"Intelligent Media Research Center (iLEARN), School of Computer Science and Technology, Shandong University, Binhailu 72, Jimo, Qingdao 266237, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jun","family":"Ma","sequence":"additional","affiliation":[{"name":"Intelligent Media Research Center (iLEARN), School of Computer Science and Technology, Shandong University, Binhailu 72, Jimo, Qingdao 266237, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7399-6211","authenticated-orcid":false,"given":"Kashif","family":"Shaheed","sequence":"additional","affiliation":[{"name":"Machine learning laboratory, School of Software Engineering, Shandong University, Jinan 250101, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,1,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1016\/j.neucom.2018.02.035","article-title":"Exudate-based diabetic macular edema recognition in retinal images using cascaded deep residual networks","volume":"290","author":"Mo","year":"2018","journal-title":"Neurocomputing"},{"key":"ref_2","first-page":"228","article-title":"International clinical diabetic retinopathy disease severity scale","volume":"68","author":"Haneda","year":"2010","journal-title":"Nihon Rinsho"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"274","DOI":"10.1016\/j.compeleceng.2018.07.042","article-title":"Deep convolutional neural networks for diabetic retinopathy detection by image classification","volume":"72","author":"Wan","year":"2018","journal-title":"Comput. 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