Abstract
Abstract: :
Purpose:: to study the effect of JPEG compression on the detection of diabetic retinopathy. Methods:Forty-five digital images selected to ensure adequate distribution of different lesions of DR were stored as TIFF files. These images, 1.26 MB in size, were compressed to five different levels using JPEG algorithm, resulting in images that were 118 Ko, 58 Ko, 41 Ko, 27 Ko, 24 Ko respectively in size ( corresponding to quality values of 80, 60, 40, 60, 20 and 10 respectively ) . Agreement between the gold standard (Tiff photographs) and the grading score for each DR lesion at each level of compression was evaluated . Results:Degradation in image quality from the original was first noticed on 41KB images (compression ratio of 1:31) . For gross anomalies such as newvessels or hard exudates , excellent agreement was observed whathever the compression level. For microaneurysms and intraretinal microvascular anomalies, good agreement was only observed with compression ratios inferior or equal to 1:31 Conclusion:High quality JPEG compression of retinal images is recommended when screening for diabetic retinopathy.
Keywords: 388 diabetic retinopathy • 430 imaging/image analysis: clinical • 554 retina