Abstract: In this paper, the vessel inscribed trigonometry (VITM) for the vessel progression orientation (VPO) is proposed in the two-dimensional fundus image. The VPO is a major factor in the optic disc (OD) detection which is a basic process in the retina analysis. To measure the VPO, skeletons of vessel are used. First, the vessels are classified into three classes as vessel end, vessel branch and vessel stem. And the chain code maps of VS are generated. Next, two farthest neighborhoods of each point on VS are searched by the proposed angle restriction. Lastly, a gradient of the straight line between two farthest neighborhoods is estimated to measure the VPO. VITM is validated by comparing with manual results and 2D Gaussian templates. It is confirmed that VPO of the proposed mensuration is correct enough to detect OD from the results of experiment which applied VITM to detect OD in fundus images.
Abstract: Glaucoma diagnosis involves extracting three features
of the fundus image; optic cup, optic disc and vernacular. Present
manual diagnosis is expensive, tedious and time consuming. A
number of researches have been conducted to automate this process.
However, the variability between the diagnostic capability of an
automated system and ophthalmologist has yet to be established. This
paper discusses the efficiency and variability between
ophthalmologist opinion and digital technique; threshold. The
efficiency and variability measures are based on image quality
grading; poor, satisfactory or good. The images are separated into
four channels; gray, red, green and blue. A scientific investigation
was conducted on three ophthalmologists who graded the images
based on the image quality. The images are threshold using multithresholding
and graded as done by the ophthalmologist. A
comparison of grade from the ophthalmologist and threshold is made.
The results show there is a small variability between result of
ophthalmologists and digital threshold.