Methods for analyzing eye

Details Methods for analyzing eye Methods for analyzing eye

2000-04-14

2001-12-04

Hindenburg, Max (Department: 3736)

Surgery

Diagnostic testing

Eye or testing by visual stimulus

Reexamination Certificate

active

06325765

ABSTRACT:

FIELD OF THE INVENTION
Improved methods for locating the pupil and verifying that a pupil has been located are disclosed. In these methods, a number of matched filter tests are employed, each testing the image array for different light intensity values indicative of structures of an iris and a pupil. Additionally, methods are disclosed for indicating types of defects in eyes of a subject, and in some instances quantification of a degree of the defects is disclosed.
BACKGROUND OF THE INVENTION
In Applicants prior application, a least squares circle fitting is used to estimate the radius of a binary pupil disk mask. Using this radius and a similarly derived radius for the iris, an impulse response array is created and used in a matched filter test to determine whether or not a valid pupil is in the image array.
One problem with this approach is that occasionally a portion of the eye, such as the eyelids and/or the white portion of the eye, may have intensity values below a threshold for creating the binary image mask. This may occur if there is low contrast in the image of the eyes. In this instance, those portions of the binary image of the iris or pupil below the threshold register as missing, which in turn reduces the correlation peak below a level necessary to obtain a detection of the pupil from the correlation peak. This results in the eye not being found.
Accordingly, it is one object of the invention to provide a more robust algorithm for reliably finding the eyes of a subject by using a plurality of matched filter tests that each examine a different part of the eyes. It is another object of the invention to provide indications of magnitude of some disease processes of the eyes. It is a further object of the invention to provide a sense of homeostasis of the eyes. Other objects will become apparent upon a reading of the following specification and appended claims.
SUMMARY OF THE INVENTION
A method for analyzing a retinal reflex is disclosed. Initially, an eye array of a subject is captured by a reflex photometer, after which an eye array is clipped and stored. If the eye array is of low contrast, then a plurality of matched filter tests are performed to locate the eye. In addition, shape determination tests may be performed in an attempt to further locate the eye. After the eye is located, a Hirshberg deviation test is performed to determine of there is any deviation of the eyes from a forward gaze. Symmetry tests may then be performed to ascertain the degree of symmetry of each eye and one eye as compared with the other.


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patent: 5632282 (1997-05-01), Hay et al.

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