Color-Coded Corneal Topographer for Accurate Surface Reconstruction
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Solution Overview
Problem
Current corneal topography methods, such as Placido based corneal topography and multiple point source topography, face challenges in accurately determining the corneal shape due to limitations in accounting for skew rays and establishing a one-to-one correspondence between light sources and image points, leading to potential errors in surface reconstruction.
Innovation Solution
A corneal topographer utilizing a multicolored stimulator with a plurality of distinct point sources of different colors, where the computational unit determines the correspondence between source and image points using color pattern information and identifiers, enabling accurate surface reconstruction through curve fitting algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple point sources are used to account for skew rays, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent assigns different colors to different point sources in the array. The camera captures the color information of reflected light from each point source, enabling automatic identification and correspondence establishment between source points and image points. This color-coding approach simplifies the complex task of matching multiple point sources to their corresponding reflections on the corneal surface.
Solution Approach 2:
The patent introduces color information as an intermediary parameter to establish correspondence between point sources and image points. Instead of directly matching geometric positions, the system uses color as a mediator - each point source has a unique color signature that appears in its reflection, making correspondence establishment straightforward through color matching.
2Measurement precision
If sequential pulsing of individual light sources is used to establish correspondence, then measurement precision is improved, but time for data acquisition increases
Solution Approach 1:
The patent illuminates all point sources simultaneously rather than pulsing them sequentially. The camera captures all color-coded point sources and their reflections in a single exposure, enabling parallel processing of all correspondences. This continuous illumination approach dramatically reduces data acquisition time while maintaining precise correspondence through color identification.
Solution Approach 2:
The patent uses the periodic/color-coded nature of point sources to enable simultaneous capture. Instead of time-based sequential activation, the system employs color-based parallel identification, where each point source's unique color signature allows the camera to distinguish and map all reflections in one continuous action.
3Device complexity
If meridional ray tracing algorithm is used, then device complexity is reduced, but measurement precision deteriorates due to inability to account for skew rays
Solution Approach 1:
The patent changes the fundamental parameters used in ray tracing by incorporating color information from each point source. This allows the system to track both meridional and skew rays accurately, as the color signature provides an additional parameter for identifying and mapping reflections regardless of ray orientation relative to the optical axis.
Solution Approach 2:
The patent adds the color dimension to the traditional spatial ray tracing approach. By incorporating color information as an additional identifying parameter, the system can accurately trace skew rays that would otherwise be difficult to distinguish from meridional rays, effectively adding another dimension to the ray tracing methodology.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for efficient establishment of a one-to-one correspondence between source and image points, facilitating accurate reconstruction of the corneal surface, including skew rays, and providing a more precise mathematical model of the corneal surface with improved accuracy and reduced time for data acquisition.
Implementation Method 1
the plurality of light rays emitted from the source points are in use reflected by the object of interest and received by a lens-camera system of the topographer
Data Source
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AI summary
A corneal topographer is described, the topographer comprising: - a multicolored stimulator comprising a plurality of light sources arranged to form a multicolored pattern of source points for projecting a plurality of light rays onto a surface of an object of interest, such as a cornea; - a lens-camera system arranged to receiving a respective plurality of reflected light rays reflected of the surface of the object of interest, thereby forming a pattern of image points; - a computational unit for determining a mathematical model of the surface; the computation unit comprising a memory unit provided with color pattern information based on the multicolored pattern of source points of the stimulator; the computational unit being arranged to, for each of the plurality of reflected light rays, establishing a one-to-one correspondence between a source point and an image point based on the color pattern information; the computational unit further being arranged to construct, based on positions of the image points and positions of the corresponding source points, the mathematical model of the surface.