Automatic Extraction and Localisation of Optic Disc in Colour Fundus Images
The color fundus images are used to track eye diseases by the ophthalmologists and it provides early signs of certain diseases such as diabetes. The optic disc extraction and segmentation is essential for the detection of many retinal diseases. The automatic screening facility helps the ophthalmologist to save time for the symptom detection. This paper presents a new histogram based multilevel thresholding method to segment and extract optic disc from colour fundus images. In this method, a hill-clustering technique is applied to the vessel free image histogram in order to determine the peak locations of the histogram and the histogram segments between the peaks are fitted by real rational functions. Finally, the multi level threshold values of the histogram are defined as the global minimum values of each rational function. This is an efficient technique for the segmentation because it is applicable to the value of image histogram directly to recognize the absolute transition point. The method was tested on a total of 404 images from publically available databases DRION, DIARETDB0 and DIARETDB1 and, also images collected from an ophthalmologist. The success rate of this method is 96.53%. The performance of the method was evaluated using the difference in centroid of the obtained optic disc and that of the ground truth obtained from an expert ophthalmologist. From the scatter plot, it is shown that the ground truth and detected optic disc centers have a high positive correlation.
Keywords: fundus image, optic disc, multilevel thresholding, local minima, global minima
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ABOUT THE AUTHORS
Thresiamma Devasia
Thresiamma Devasia was graduated with Bachelor of Mathematics (BSc.Maths) from Mahatma University, Kerala, India in 1991, and finished her master of computer applications (MCA) and M.Phil Computer Science from Alagappa University Tamilnadu, India in 1995 and 2010, respectively. Currently, she is the Head of the Department and Associate professor, Department of Computer Science, Assumption College Changanacherry, Kerala, India and working toward her Ph.D. at Cochin University of Science And Technology on glaucoma detection using image processing. She completed UGC sponsored minor research project based on image processing. She was a member of IEEE. Her interest areas include image processing and medical imaging.
Poulose Jacob
Dr. K.Poulose Jacob, Professor of Computer Science at Cochin University of Science and Technology since 1994, is currently Pro Vice Chancellor of Cochin University of Science & Technology. He has presented research papers in several International Conferences in Europe, USA, UK, Australia and other countries. He has served as a Member of the Standing Committee of the UGC on Computer Education & Development. He is the Zonal Coordinator of the DOEACC Society under the Ministry of Information Technology, Government of India. He serves as a member of the AICTE expert panel for accreditation and approval. He has been a member of several academic bodies of different Universities and Institutes. He is on the editorial board of two international journals in Computer Science. Dr. K.Poulose Jacob is a Professional member of the ACM (Association for Computing Machinery) and a Life Member of the Computer Society of India.
Tessamma Thomas
Dr.Tessamma Thomas received her M.Tech. and Ph.D from Cochin University of Science and Technology, Cochin-22, India. At present she is working as Professor in the Department of Electronics, Cochin University of Science and Technology. She has to her credit more than 100 research papers, in various research fields, published in International and National journals and conferences. Her areas of interest include digital signal / image processing, bio medical image processing, super resolution, content based image retrieval, genomic signal processing, etc.
Thresiamma Devasia
Thresiamma Devasia was graduated with Bachelor of Mathematics (BSc.Maths) from Mahatma University, Kerala, India in 1991, and finished her master of computer applications (MCA) and M.Phil Computer Science from Alagappa University Tamilnadu, India in 1995 and 2010, respectively. Currently, she is the Head of the Department and Associate professor, Department of Computer Science, Assumption College Changanacherry, Kerala, India and working toward her Ph.D. at Cochin University of Science And Technology on glaucoma detection using image processing. She completed UGC sponsored minor research project based on image processing. She was a member of IEEE. Her interest areas include image processing and medical imaging.
Poulose Jacob
Dr. K.Poulose Jacob, Professor of Computer Science at Cochin University of Science and Technology since 1994, is currently Pro Vice Chancellor of Cochin University of Science & Technology. He has presented research papers in several International Conferences in Europe, USA, UK, Australia and other countries. He has served as a Member of the Standing Committee of the UGC on Computer Education & Development. He is the Zonal Coordinator of the DOEACC Society under the Ministry of Information Technology, Government of India. He serves as a member of the AICTE expert panel for accreditation and approval. He has been a member of several academic bodies of different Universities and Institutes. He is on the editorial board of two international journals in Computer Science. Dr. K.Poulose Jacob is a Professional member of the ACM (Association for Computing Machinery) and a Life Member of the Computer Society of India.
Tessamma Thomas
Dr.Tessamma Thomas received her M.Tech. and Ph.D from Cochin University of Science and Technology, Cochin-22, India. At present she is working as Professor in the Department of Electronics, Cochin University of Science and Technology. She has to her credit more than 100 research papers, in various research fields, published in International and National journals and conferences. Her areas of interest include digital signal / image processing, bio medical image processing, super resolution, content based image retrieval, genomic signal processing, etc.
