Optimizing retinal image digitization for improved digital processing and visualization

Determines if a relationship exists between quantitative measures of digital retinal image quality, such as contrast and spatial resolution, and perceptual preferences of human graders. Ad-hoc digitization of retinal 35-mm color slides is less than optimal due to the unusual light scattering properties of the retina. Quantitative and qualitative measures of contrast and entropy were calculated for two test images. The resolution was determined by a scanning procedure. A pairwise comparison technique was adopted for measuring the medical technician´s visual preference, and the results were analyzed using a formal quantitative methodology. The results showed that measures such as entropy and contrast generally correlated with the perceived image quality. A single, universally applicable set of scanning parameters was not found that would consistently produce the most preferred image for all image quality criteria