Real-time optical and digital image stabilization for adaptive optics scanning ophthalmoscopy
Inventors
Assignees
Montana State University Bozeman • University of Rochester
Publication Number
US-9226656-B2
Publication Date
2016-01-05
Expiration Date
2034-09-11
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Abstract
A real-time ophthalmoscope system for imaging an eye includes a wide field scanning light ophthalmoscope (SLO) configured for wide field imaging of the eye. The system also includes a small field SLO configured for high resolution imaging of the eye. A 2D tracking minor electrically coupled to a computer, and a 2D steering minor electrically coupled to the computer, are both disposed in an optical path between the small field SLO and the eye. The system is configured to acquire a plurality of small field images at a plurality of locations on the eye as defined by the 2D steering minor, each of the small field images is stabilized for a motion of the eye by the 2D tracking minor. A method for imaging of the eye is also described.
Core Innovation
The invention describes a real-time ophthalmoscope system for imaging the eye that incorporates both a wide field scanning light ophthalmoscope (SLO) for wide field imaging and a small field SLO for high resolution imaging. A 2D tracking mirror and a 2D steering mirror, both electrically coupled to a computer, are positioned in the optical path between the small field SLO and the eye. The system is able to acquire multiple high-resolution small field images at various locations on the eye, as determined by the 2D steering mirror, with each image stabilized for eye movement by the 2D tracking mirror.
A key problem addressed by the invention is eye motion, which impedes the efficient acquisition of high quality, artifact-free retinal images, especially in adaptive optics scanning ophthalmoscopy. Existing techniques either lack spatial resolution, are susceptible to image 'frame out,' or require extensive post-processing and are not real time. The present system addresses these limitations by combining both optical (hardware) and digital (software) image stabilization in real time, significantly reducing the residual eye motion and allowing efficient and accurate image registration.
The invention utilizes closed-loop control of the tracking mirror, updated at high frequencies (e.g., 1 kHz), with motion tracking information derived from both the wide field SLO and the small field SLO. Residual motion not corrected by the tracking mirror is further addressed by digital stabilization methods, which can achieve sub-pixel accuracy. The end result is the efficient creation of stabilized, high-resolution images and montages of the retina, with significantly reduced need for post-processing.
Claims Coverage
The independent claims of this patent define two main inventive features: a real-time ophthalmoscope system and a method for imaging an eye utilizing integrated hardware and software stabilization.
Real-time ophthalmoscope system with integrated wide and small field SLO, 2D tracking mirror, and 2D steering mirror
The system comprises: - A wide field scanning light ophthalmoscope (SLO) electrically coupled to a computer for wide field imaging. - A small field SLO electrically coupled to the computer for high resolution imaging. - A 2D tracking mirror and a 2D steering mirror, each electrically coupled to the computer and positioned in an optical path between the small field SLO and the eye. - The system is configured to acquire multiple small field images at various locations on the eye, defined by the 2D steering mirror, with each image stabilized for eye motion by the 2D tracking mirror.
Method for imaging an eye using coordinated wide and small field SLOs and real-time optical and digital stabilization
The method includes the steps of: 1. Providing a wide field SLO and a small field SLO, each electrically coupled to respective computers, a 2D tracking mirror, and a 2D steering mirror disposed in the optical path between the small field SLO and the eye. 2. Pointing the small field SLO to locations on the eye for imaging. 3. Stabilizing the small field SLO against eye movement by using the 2D tracking mirror, controlled by at least the wide field SLO. 4. Imaging each location to provide a stabilized image. 5. Repeating the imaging and stabilization at multiple locations. 6. Montaging the stabilized images to form a composite image of the eye.
In summary, the inventive features are directed to a system and method which combine wide and small field ophthalmoscopes, 2D tracking and steering mirrors, and real-time optical and digital stabilization to achieve high-resolution, motion-stabilized retinal imaging.
Stated Advantages
The integrated system can dramatically reduce patients' clinical imaging time from several hours to 20 to 30 minutes.
The apparatus can significantly improve the efficiency of adaptive optics scanning light ophthalmoscope imaging even in eyes with poor fixation due to retinal diseases.
The solution enables high-resolution eye laser surgery with an accuracy of several micrometers.
The approach eliminates tedious post-processing of large video volumes by enabling real-time acquisition and registration.
The apparatus allows high-resolution images from the small field system to be registered and montaged in real time.
The system’s real-time tracking can reduce RMS error to less than 2 micrometers.
For scientific uses, the apparatus allows efficient and accurate tracking of retinal positions inside the wide field of view.
Documented Applications
Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO).
Scanning Laser Ophthalmoscope (SLO).
Most scanning-based imaging systems.
High-resolution eye laser surgery with several micrometers of operational accuracy on the living retina.
Real-time montaging and registration of retinal images for clinical and scientific research applications.
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