Spectacle Lens Centering from Calibrated 3D Frame Geometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining centering parameters for spectacle lenses are cumbersome and disruptive, requiring cumbersome attachment of measuring devices and uncalibrated image capture.
Innovation Solution
A computer-implemented method using calibrated images and geometric parameters to determine the position of the corneal vertex, employing epipolar geometry and triangulation, and adapting planes to nasal and temporal frame edges for simplified lens positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measuring devices are attached to eyeglasses or eyeglass frames for determining centering parameters, then measurement capability is improved, but ease of operation deteriorates due to cumbersome attachment and disruption
Solution Approach 1:
The patent replaces mechanical measuring devices attached to glasses with an optical imaging system using cameras. The system captures images of the wearer's face and uses image processing algorithms to automatically determine centering parameters, eliminating the need for physical attachment of measuring devices to the eyeglasses or frames.
2Device complexity
If uncalibrated images are used for determining centering parameters, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent implements a calibration phase before actual measurement, where the camera system captures images of a calibration object with known geometric features. These calibration images are used to determine transformation matrices that map image coordinates to real-world coordinates, ensuring accurate centering parameter measurement while maintaining a relatively simple device structure.
3Manufacturing precision
If complex models are used for spectacle lens positioning, then manufacturing precision is improved, but calculation efficiency deteriorates
Solution Approach 1:
The patent extracts and utilizes only the essential geometric features needed for centering parameter determination from the captured images, such as pupil positions, frame geometry, and key reference points. By focusing on these critical features rather than processing complete complex models, the system achieves sufficient positioning accuracy while maintaining high calculation efficiency.
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
The invention relates to a computer-implemented method for determining centering parameters for adjusting spectacle lenses to a specified spectacle frame and to the head of a subject, with at least two calibrated images of the head wearing the spectacle frame, taken from different recording directions, being provided, with geometric parameters being determined by means of geometric position determination , which describe the position of the eyes and the geometry of the spectacle frame, and centering parameters are calculated from the geometric parameters. According to the invention, a three-dimensional model for the spectacle lenses to be accommodated in the spectacle frame is adapted to the geometric parameters describing the geometry of the spectacle frame.