Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Articles Article Faculty Publications -Articles Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource An objective function based technique for devignetting fundus imagery using MST Subject The topic of the resource Average gradient of illumination component; Devignetting; Error of enhancement; Fundus imagery; Illumination correction; Modified sigmoid transform (MST); Objective function Description An account of the resource Fundus photography is a powerful imaging modality that is utilized for detecting macular degeneration, retinal neoplasms, choroid disturbances, glaucoma and diabetic retinopathy. As the illumination source in fundus imaging is situated at the center of the fundus camera, the illumination at the peripheral regions of the images would be relatively less than the center, which is termed vignetting. Vignetting adversely affects the performance of computerized methods for analyzing fundus imagery. A devignetting method for fundus imagery based on the Modified Sigmoid Transform (MST) is proposed in this paper. Gain (A) and centering parameter (?) of MST have a crucial influence on its performance. For low values of the gain, local contrast is penalized, and the overall dynamic range is compressed. When the value of gain is very high, the images after the illumination correction will have a washed out appearance. The optimum value of gain is determined in this paper from an objective method based on two statistical indices, Average Gradient of Illumination Component (AGIC) and Error of Enhancement (EME). MST with gain value defined via objective methods is able to correct the uneven illumination in fundus images without penalizing the local contrast. The proposed method is compared with illumination equalization model, homomorphic filtering and Adaptive Gamma Correction (AGC) and was found to be superior in terms of naturality uniformity of background illumination, and computational speed. 2018 Creator An entity primarily responsible for making the resource Shamsudeen F.M.; Raju G. Source A related resource from which the described resource is derived Informatics in Medicine Unlocked, Vol-14, pp. 82-91. Publisher An entity responsible for making the resource available Elsevier Ltd Date A point or period of time associated with an event in the lifecycle of the resource 2019-01-01 Identifier An unambiguous reference to the resource within a given context <a href="https://doi.org/10.1016/j.imu.2018.10.001" target="_blank" rel="noreferrer noopener">https://doi.org/10.1016/j.imu.2018.10.001</a> <br /><br /><a href="https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063113770&amp;doi=10.1016%2Fj.imu.2018.10.001&amp;partnerID=40&amp;md5=397867d4f7a3de513dde9ed18dc3c689" target="_blank" rel="noreferrer noopener">https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063113770&amp;doi=10.1016%2fj.imu.2018.10.001&amp;partnerID=40&amp;md5=397867d4f7a3de513dde9ed18dc3c689</a> Rights Information about rights held in and over the resource All Open Access; Gold Open Access Relation A related resource ISSN: 23529148 Format The file format, physical medium, or dimensions of the resource Online Language A language of the resource English Type The nature or genre of the resource Article Coverage The spatial or temporal topic of the resource, the spatial applicability of the resource, or the jurisdiction under which the resource is relevant Shamsudeen F.M., School of Computer Science, MG University, Kottayam, India, Department of Computer Applications, TKM College of Engineering, India; Raju G., Department of Computer Science and Engineering, Faculty of Engineering, Christ (deemed to be University), Kanminike, Kumbalagod Post, Bengaluru, 560074, India