Apparatus and method for the analysis of retinal vessels
First Claim
Patent Images
1. An apparatus for the analysis of retinal vessels comprising:
- a retinal camera for recording images of the ocular fundus;
at least one image storage;
means for detecting arterial and venous vessels in the images;
means for determining the vessel diameters of the detected arterial and venous vessels;
means for determining artery-to-vein ratios from the determined vessel diameters;
said retinal camera being connected to an image sequence control unit which carries out a control of the time intervals or times which is adapted to the period of vasomotor waves and a control of the quantity of images of a sequence of images to be recorded for which an image sequence storage is provided for storing images; and
said means for determining artery-to-vein ratios being designed to determine a mean artery-to-vein ratio from artery-to-vein ratios which are determined from at least two images of an image sequence.
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Abstract
The object of an apparatus and a method for the analysis of retinal vessels is to improve the reproducibility of individually determined artery-to-vein ratios and to reduce the measurement uncertainty in determining the artery-to-vein ratio in order to substantially increase the individual validity of the determined values for vessel diagnosis. At least two images are recorded successively as an image sequence in a predetermined timed sequence adapted to the vasomotricity of the vessels and are evaluated such that a mean artery-to-vein ratio is formed from artery-to-vein ratios that are determined on the basis of the at least two images.
70 Citations
25 Claims
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1. An apparatus for the analysis of retinal vessels comprising:
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a retinal camera for recording images of the ocular fundus; at least one image storage; means for detecting arterial and venous vessels in the images; means for determining the vessel diameters of the detected arterial and venous vessels; means for determining artery-to-vein ratios from the determined vessel diameters; said retinal camera being connected to an image sequence control unit which carries out a control of the time intervals or times which is adapted to the period of vasomotor waves and a control of the quantity of images of a sequence of images to be recorded for which an image sequence storage is provided for storing images; and said means for determining artery-to-vein ratios being designed to determine a mean artery-to-vein ratio from artery-to-vein ratios which are determined from at least two images of an image sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for the analysis of retinal vessels comprising the steps of:
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evaluating digital fundus images in which a ring-shaped measurement zone containing vessel portions which proceed from a central vessel, which are to be distinguished as arteries or veins, and which are to be measured; arranging said measurement zone around the papilla at a distance therefrom; determining a vessel diameter for each of these vessel portions; determining a retinal arterial vessel diameter equivalent and a retinal venous vessel diameter equivalent from the determined vessel diameters of the arterial and venous vessel portions; determining an artery-to-vein ratio is determined from the vessel diameter equivalents of the arteries and veins; recording at least two images, as fundus images to be evaluated, successively in a timed sequence that is adapted to the period of vasomotor waves as an image sequence; and forming a mean artery-to-vein ratio from artery-to-vein ratios that are determined based on the at least two images. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification