this paper presents an automated method for detecting microaneurysms in the retinal angiographic images by using image processing techniques. in the presented method, in order to fade or remove the pseudo images, first retinal images are pre-processed. then microaneurysms are identified by circular hough transform. in the existing methods of detecting microaneurysms, it is necessary to identify...

Natural image retrieval is a main challenge for image indexing. For image retrieval systems, colour information is one of the most important features. In this work, we propose a perceptive colour space based on a biological model of the retina. In this space, a model of Gaussian mixture appears very efficient for colour distribution. Two strategies are presented, retrieval by maximum likelihood...

A method is proposed to determine the mechanical properties of retina based on in vivo experiments and numerical simulations. First, saline water was injected into the anterior chamber of the right eye of a cat to cause acute high intraocular pressure. After the eye was scanned using optical coherence tomography under different acute high intraocular pressures, the images of the retina in vivo ...

Changes in lighting conditions strongly effect the performance and reliability of computer vision systems. We report face recognition results under drastically changing lighting conditions for a computer vision system which concurrently uses a contrast sensitive silicon retina and a conventional, gain controlled CCO camera. For both input devices the face recognition system employs an elastic m...

The large amounts of digital image data now becoming available make softcopy imagery exploitation a desirable ca­ pability. One aspect of digital imagery exploitation, image magnification is studied. Two filtering techniques to main^ tain image sharpness as digital images are enlarged are developed. The most promising technique includes the use of a model of the retina of the eye. An example is...

Our eyes never remain still. Even when we stare at a fixed point, small involuntary movements take place in our eyes in an imperceptible manner. Researchers agree on the presence of three main contributions to eye movements when we fix the gaze: microsaccades, drifts and tremor. These small movements carry the image across the retina stimulating the photoreceptors and thus avoiding fading. Nowa...

We report a quantitative analysis of the different bipolar cell types of the mouse retina. They were identified in wild-type mice by specific antibodies or in transgenic mouse lines by specific expression of green fluorescent protein or Clomeleon. The bipolar cell densities, their cone contacts, their dendritic coverage, and their axonal tiling were measured in retinal whole mounts. The results...

We discuss methods for generating retina codes from retinal images for biometric user authentication. First the optical disc as a central reference point is located by using Hough transform followed by a segmentation of the retina vasculature by filtering with the continuous two-dimensional Morlet wavelet transform and classifying each pixel as vessel or non vessel by simple thresholding. Start...

Teleophthalmology holds a great potential to improve the quality, access, and affordability in health care. For patients, it can reduce the need for travel and provide the access to a super-specialist. Ophthalmology lends itself easily to telemedicine as it is a largely image based diagnosis. The main goal of the proposed system is to diagnose the type of disease in the retina and to automatica...

The retina performs various key operations on incoming images in order to facilitate higher-level visual processing. Since the retina outperforms existing image enhancing techniques, it follows that computational simulations with biological plausibility are best suited to inform their design and development, as well as help us better understand retina functionality. Recently, it has been determ...