Retinal image size can be used to judge objects' distances because for any object one can assume that some sizes are more likely than others. It has been shown that an increased variability in the size of otherwise identical target objects over trials reduces the weight given to retinal image size as a distance cue. Here, we examined whether an increased variability in the size of objects of a ...

We propose a method for retinal image matching that can be used in image matching for person identification or patient longitudinal study. Vascular invariant features are extracted from the retinal image, and a feature vector is constructed for each of the vessel segments in the retinal blood vessels. The feature vectors are represented in a tree structure with maintaining the vessel segments a...

Retinal vessel segmentation is critical in detecting retinal blood vessels for a variety of eye disorders, and consistent computerized method required automatic disorder screening. Many methods are implemented, but these only yielded accuracy lack good sensitivity due to the coherence segmentation. Another main factor low proper technique handle low-varying contrast problem. In this study, we p...

PURPOSE To investigate whether retinal vessel calibre measurements on optical retinal photography are affected by light and dark exposure prior to photography and whether the vessel calibre changes during an imaging sequence of several images. METHODS Digital optical retinal photographs were obtained from 32 healthy adults in two separate image sequences of six images during 1 min; one sequen...

Current digital image/video storage, transmission and display technologies use uniformly sampled images. On the other hand, the human retina has a nonuniform sampling density that decreases dramatically as the solid angle from the visual fixation axis increases. Therefore, there is sampling mismatch between the uniformly sampled digital images and the retina. This paper introduces retinally rec...

A novel topological segmentation of retinal images represents blood vessels as connected regions in the continuous image plane, having shape-related analytic and geometric properties. This paper presents topological segmentation results from the DRIVE retinal image database [SAN∗04].

Morphological changes in the retinal vascular network are associated with future risk of many systemic and vascular diseases. However, uncertainty over the presence and nature of some of these associations exists. Analysis of data from large population based studies will help to resolve these uncertainties. The QUARTZ (QUantitative Analysis of Retinal vessel Topology and siZe) retinal image ana...

Even when the retinal image of a static scene is constantly shifting, as occurs when the viewer pursues a small moving object with his or her eyes, the scene is usually correctly perceived to be static. Following early suggestions by von Helmholtz, it is commonly believed that this spatial stability is achieved by combining retinal and extra-retinal signals. Here, we report a perceptually salie...