Iris-Pupil Contrast Enhancement for Ophthalmic Laser Alignment
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Solution Overview
Problem
Current ophthalmic laser surgery systems face challenges in accurately centrating and aligning the laser with the eye, particularly for darker-colored eyes, due to limited contrast between the iris and pupil, and conventional digital video cameras have restricted image resolution and magnification capabilities.
Innovation Solution
A system comprising a laser assembly, user interface, and controller that produces and enhances the contrast between the iris and pupil in digital images, allowing for improved centration and alignment by selectively increasing contrast and directing a pulsed laser beam based on enhanced digital images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional digital video cameras are used for imaging the eye, then the system is simple and cost-effective, but the image resolution and magnification capabilities are limited, making it difficult to delineate the pupil from the iris for darker-colored eyes
Solution Approach 1:
The patent combines a digital camera with an image processor to create an integrated imaging system. The image processor is coupled to the digital camera and performs contrast enhancement processing on the captured images, merging the functions of image capture and image processing into a single system that achieves high resolution and dark eye differentiation capabilities without requiring separate complex equipment.
Solution Approach 2:
The image processor acts as an intermediary between the digital camera and the display device. It receives images from the camera, applies contrast enhancement algorithms to improve the delineation of pupil and iris in dark-colored eyes, and then outputs the enhanced images for display. This intermediary processing step enables the system to overcome the limitations of conventional cameras without replacing them with more complex equipment.
2Illumination intensity
If light intensity or light source direction is modified to improve overall brightness, then the overall brightness of the imaged eye increases, but the contrast between the iris and pupil is not sufficiently differentiated for darker-colored eyes
Solution Approach 1:
The image processor applies different contrast enhancement treatments to different regions of the image. Specifically, it enhances the contrast between the iris and pupil regions while maintaining appropriate overall brightness. This local quality adjustment ensures that dark-colored eyes can be properly differentiated without sacrificing overall image brightness, addressing the limitation of conventional uniform brightness adjustment.
Solution Approach 2:
The system changes the contrast parameter of the image through digital processing rather than physically changing light intensity. The image processor modifies the luminance values of different regions in the image to enhance iris-pupil contrast while maintaining overall brightness. This parameter change approach allows simultaneous optimization of both overall brightness and local contrast that cannot be achieved through physical light source modification alone.
3Measurement precision
If conventional contrast controls on displays are adjusted, then the general contrast of the displayed image varies to some degree, but the brightness difference between brown-colored iris and black-colored pupil is not sufficiently differentiated
Solution Approach 1:
The image processor performs contrast enhancement processing on the images before they are displayed. By pre-processing the images to enhance iris-pupil contrast, the system eliminates the need for operators to manually adjust display contrast controls to achieve adequate differentiation. This preliminary action ensures that dark-colored eyes are sufficiently differentiated from the outset, making the system easier to operate effectively.
Data Source
AI summary
System and method of photoaltering a region of an eye using an enhanced contrast between the iris and the pupil of the imaged eye. The system includes a laser assembly outputting a pulsed laser beam, a user interface displaying one of a first digital image of the eye and a second digital image of the eye, and a controller coupled to the laser assembly and the user interface. The first digital image has a first contrast between the pupil and the iris, and the second digital image has a second contrast between the pupil and the iris. The controller selectively increases the first contrast between the pupil and the iris to the second contrast between the pupil and the iris and directs the pulsed laser beam to the region of the eye based on one of the first and second digital images.