title: Application of higher-order spectra for automated grading of diabetic maculopathy.
abstract: Diabetic macular edema (DME) is one of the most common causes of visual loss among diabetes mellitus patients. Early detection and successive treatment may improve the visual acuity. DME is mainly graded into non-clinically significant macular edema (NCSME) and clinically significant macular edema according to the location of hard exudates in the macula region. DME can be identified by manual examination of fundus images. It is laborious and resource intensive. Hence, in this work, automated grading of DME is proposed using higher-order spectra (HOS) of Radon transform projections of the fundus images. We have used third-order cumulants and bispectrum magnitude, in this work, as features, and compared their performance. They can capture subtle changes in the fundus image. Spectral regression discriminant analysis (SRDA) reduces feature dimension, and minimum redundancy maximum relevance method is used to rank the significant SRDA components. Ranked features are fed to various supervised classifiers, viz. Naive Bayes, AdaBoost and support vector machine, to discriminate No DME, NCSME and clinically significant macular edema classes. The performance of our system is evaluated using the publicly available MESSIDOR dataset (300 images) and also verified with a local dataset (300 images). Our results show that HOS cumulants and bispectrum magnitude obtained an average accuracy of 95.56 and 94.39% for MESSIDOR dataset and 95.93 and 93.33% for local dataset, respectively.
authors.affiliation: Department of Electronics and Computer Engineering, Ngee Ann Polytechnic, Clementi, 599489, Singapore. mkm2@np.edu.sg.
authors.forename: Muthu Rama Krishnan
authors.initials: MR
authors.lastname: Mookiah
authors.affiliation: Department of Electronics and Computer Engineering, Ngee Ann Polytechnic, Clementi, 599489, Singapore. aru@np.edu.sg.|Department of Biomedical Engineering, School of Science and Technology, SIM University, Clementi, 599491, Singapore. aru@np.edu.sg.|Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia. aru@np.edu.sg.
authors.forename: U Rajendra
authors.initials: UR
authors.lastname: Acharya
authors.affiliation: School of Electrical Engineering and Computer Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia. v.chandran@qut.edu.au.
authors.forename: Vinod
authors.initials: V
authors.lastname: Chandran
authors.affiliation: Department of Electronics and Communication Engineering, St. Joseph Engineering College, Vamanjoor, Mangalore, 575028, Karnataka, India. roshaniitsmst@gmail.com.
authors.forename: Roshan Joy
authors.initials: RJ
authors.lastname: Martis
authors.affiliation: Department of Electronics and Computer Engineering, Ngee Ann Polytechnic, Clementi, 599489, Singapore. tjh6@np.edu.sg.
authors.forename: Jen Hong
authors.initials: JH
authors.lastname: Tan
authors.affiliation: Department of Electronics and Computer Engineering, Ngee Ann Polytechnic, Clementi, 599489, Singapore. kje2@np.edu.sg.
authors.forename: Joel E W
authors.initials: JE
authors.lastname: Koh
authors.affiliation: Department of Electronics and Computer Engineering, Ngee Ann Polytechnic, Clementi, 599489, Singapore. ckc@np.edu.sg.
authors.forename: Chua Kuang
authors.initials: CK
authors.lastname: Chua
authors.affiliation: Ocular Surface Research Group, Singapore Eye Research Institute, Singapore, 168751, Singapore. louis.tong.h.t@snec.com.sg.|Singapore National Eye Center, Singapore, 168751, Singapore. louis.tong.h.t@snec.com.sg.|Duke-NUS Graduate Medical School, Singapore, 169857, Singapore. louis.tong.h.t@snec.com.sg.|Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore. louis.tong.h.t@snec.com.sg.
authors.forename: Louis
authors.initials: L
authors.lastname: Tong
authors.affiliation: National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, 308433, Singapore. laude_augustinus@ttsh.com.sg.
authors.forename: Augustinus
authors.initials: A
authors.lastname: Laude
mesh_terms: D000328:Adult; D003930:Diabetic Retinopathy / Q000145:classification* / Q000175:diagnosis*; D003941:Diagnostic Techniques, Ophthalmological; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008269:Macular Edema / Q000145:classification* / Q000175:diagnosis*; D008875:Middle Aged; D012372:ROC Curve; D055815:Young Adult
keywords: Computer-aided diagnosis; Diabetic maculopathy; Higher-order spectra; Retina; Spectral regression discriminant analysis