T. Spencer et al., IMAGE-PROCESSING STRATEGY FOR THE SEGMENTATION AND QUANTIFICATION OF MICROANEURYSMS IN FLUORESCEIN ANGIOGRAMS OF THE OCULAR FUNDUS, Computers and biomedical research, 29(4), 1996, pp. 284-302
Digital image-processing techniques can provide an objective and highl
y repeatable way of quantifying retinal pathology. This study describe
s an image-processing strategy which detects and quantifies microaneur
ysms present in digitized fluorescein angiograms. After preprocessing
stages, a bilinear top-hat transformation and matched filtering are em
ployed to provide an initial segmentation of the images. Thresholding
this processed image results in a binary image containing candidate mi
croaneurysms. A novel region-growing algorithm fully delineates each m
arked object and subsequent analysis of the size, shape, and energy ch
aracteristics of each candidate results in the final segmentation of m
icroaneurysms. The technique is assessed by comparing the computer's r
esults with microaneurysm counts carried out by five clinicians, using
Receiver Operating Characteristic (ROC) curves. The performance of th
e automated technique matched that of the clinicians' analyses. This s
trategy is valuable in providing a way of accurately monitoring the pr
ogression of diabetic retinopathy. (C) 1996 Academic Press, Inc.