Events
CRiSM Seminar - Dr Abhir Bhalerao
Dr Abhir Bhalerao, University of Warwick
Automatic Screening for Microaneurysms in Digital Images
Diabetic retinopathy is one of the major causes of blindness. However, diabetic retinopathy does not usually casuse a loss of sight until it has reached an advanced stage. The earliest signs of the disease are microaneurysms (MA) which appear as small red dots on retinal fundus images. Various screening programmes have been established in the UK and other coutries to collect and assess images on a regular basis, especially in the diabetic population. A considerable amount of time and money is spent in manually grading these images, a large percentage of which are normal. By automatically identifying the normal images, the manual workload and costs could be reducced greatly while increasing the effectiveness of the screening programmes. A novel method of microaneurysm from digital retinal screening images is presented. It is based on image filtering using complex-valued circular-symmetric filters, and an eigen-image, morphological analysis of the candidate regions to reduce the false-positive rate. The image processing algorithms will be presented with evaluation on a typical set of 89 images from a published database. Teh resulting method is shown to have a best operating sensitivity of 82.6% at a specificity of 80.2% which makes is useful for screening. The results are discussed in the context of a model of visual search and the ROC curves that it can predict.
More…