Ophthalmic Lens Fitting via Head Inclination Correction
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Solution Overview
Problem
Current methods for determining geometric-physiognomic parameters for ophthalmic lens mounting on a wearer's face are inaccurate due to unnatural postures and adverse light conditions during image capture, leading to errors in measurements such as interpupillary distance and pantoscopic angle.
Innovation Solution
A method that accounts for the difference between the actual and natural postures of the wearer by measuring the angle of inclination using an inclinometer and correcting the measured geometric parameters to obtain values relevant to the natural posture, regardless of light conditions, through frontal and profile image analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wearer approaches the measuring device at a short distance for image capture or manual measurement, then the speed of execution and comfort are improved, but the wearer's head posture becomes unnatural and measurement accuracy deteriorates
Solution Approach 1:
The patent introduces an inclinometer as an intermediary device that measures the wearer's head inclination angle independently. This allows the system to capture images at convenient distances while compensating for posture deviations through mathematical correction, thus maintaining both speed and accuracy.
Solution Approach 2:
The system changes the parameter being measured from direct geometric parameters to inclination angle parameters. By measuring the inclination angle and using it to correct the geometric parameters, the system can work with unnatural postures while still obtaining accurate results for the natural posture parameters.
2Measurement precision
If manual adjustment of sharpness and brightness is performed before each image capture, then image quality is improved, but the process becomes long and tedious
Solution Approach 1:
The image capture device performs self-adjustment of sharpness and brightness parameters automatically. The device captures test images, analyzes their quality, and adjusts its parameters without optician intervention, making the process both quick and effective.
Solution Approach 2:
The system implements a feedback loop where the sharpness and brightness of captured images are evaluated, and this information is used to automatically adjust the image capture parameters for subsequent images, ensuring consistent quality without manual intervention.
3Ease of operation
If the image capture device automatically adjusts focal length, then the operation is simplified, but the wearer's head may appear blurry in the captured image
Solution Approach 1:
The system automatically evaluates the sharpness of the captured image and, if necessary, triggers an automatic refocusing routine. This self-service mechanism ensures that the image is sharp enough for accurate measurement without requiring manual focus adjustment.
Data Source
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AI summary
The invention relates to a method for determining, in a natural posture, at least one geometric/physiognomic parameter associated with the mounting of an ophthalmic lens in a spectacle frame intended to be worn by a wearer. The method comprises the following steps consisting in: (a) capturing at least one substantially frontal image of the wearer's head; (b) determining a measured value of an angle of inclination (A) during the capture of the substantially frontal image, which depends on the inclination of the wearer's head about a main axis perpendicular to a sagittal plane of the wearer's head; (c) determining a reference value of said angle of inclination corresponding to a natural posture of the wearer's head (10); and (d) determining the required geometric/physiognomic parameter on the basis of the substantially frontal image captured and as a function of the difference between the measured value of the angle of inclination determined in step (b) and the reference value of the angle of inclination determined in step (c).