Eyeball Imaging Camera Line of Sight Correction for Spectacle Lenses
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Solution Overview
Problem
Conventional line of sight detection devices fail to accurately calculate the direction of line of sight and angle of rotation of eyeballs when a subject wears optical means like eyeglasses, leading to errors in lens design and wearer dissatisfaction due to refractive changes.
Innovation Solution
A measurement system and method that includes a line of sight detection device with a distortion correction unit and a line of sight information correction device, which corrects for errors caused by eyeglasses by adjusting the position of the eyeball imaging camera and using optical information to refine the line of sight data, ensuring precision in lens design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional line of sight detection devices are used without correction for optical means, then the device construction remains simple, but measurement precision deteriorates due to errors in calculating direction of line of sight and angle of rotation when subjects wear eyeglasses
Solution Approach 1:
The patent introduces an eyeball imaging camera as an intermediary device that captures images of the eyeball to detect the line of sight. This mediator allows the system to observe the actual eyeball position and orientation, enabling correction of measurement errors caused by optical means like eyeglasses. The eyeball imaging camera serves as a bridge between the subject's eyes and the measurement system, providing direct visual data that can be used to calculate accurate line of sight and angle of rotation even when optical means are present.
2Measurement precision
If calibration measurements are improved by increasing sample counts or changing sample point positions, then measurement precision improves, but device complexity and operational complexity increase
Solution Approach 1:
The patent creates a virtual model (copy) of the eyeball based on images captured during calibration. This virtual eyeball model includes parameters such as the position of the center of rotation and the shape of the eyeball surface. Once created, this copy can be used repeatedly for measurements without requiring repeated complex calibration procedures. The system uses this copied model to calculate line of sight and angle of rotation, eliminating the need for frequent recalibration and reducing operational complexity while maintaining high measurement precision.
3Manufacturing precision
If uniform treatment of calibration samples is applied regardless of lens asymmetry, then ease of operation is maintained, but manufacturing precision deteriorates for progressive power lenses with asymmetrical shapes
Solution Approach 1:
The patent applies local quality by adjusting the calibration procedure based on the specific characteristics of each lens. The system detects the type of lens (e.g., progressive power lens, single vision lens) and applies appropriate calibration methods tailored to each lens type. For progressive power lenses with asymmetrical shapes, the system uses specific sample point positions and calibration procedures that account for the lens asymmetry. This localized approach ensures high manufacturing precision for each lens type without requiring a single complex universal procedure.
4Ease of operation
If desktop-installed eyeball imaging camera is used instead of wearable device, then ease of operation improves by eliminating troublesome operations, but measurement precision deteriorates due to inability to distinguish seeing sideward by rotating only eyeballs from seeing sideward by rotation of eyeballs along with rotation of head
Solution Approach 1:
The patent implements feedback by using the desktop-installed eyeball imaging camera to continuously monitor the subject's head position and eyeball movement. The system captures images of the eyeball and uses this feedback information to distinguish between pure eyeball rotation and combined eyeball-head rotation. By analyzing the relationship between head position (detected by the desktop camera) and eyeball orientation (detected by the eyeball imaging camera), the system can accurately calculate the line of sight and angle of rotation even when the subject moves their head, maintaining measurement precision while enjoying the ease of desktop installation.
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
The system provides accurate line of sight information with reduced errors, enabling the design of spectacle lenses that better match the wearer's actual line of sight, improving client satisfaction by minimizing aberrations and ensuring proper vision correction.
Implementation Method 1
A technique known in the art irradiates infrared light at a front side of the eyeballs, captures images formed by the infrared light reflected by the cornea using the eyeball imaging camera
Data Source
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AI summary
A line of sight information correction device includes: an input unit that inputs line of sight information obtained based on a condition of an eyeball of a subject who wears an optical instrument that refracts light to enter the eyeball; and a calculation unit that corrects the line of sight information input into the input unit using optical information relating to refraction of the light at the optical instrument.