Automated Spectacle Frame Fitting via Parametric Head Model Transfer
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Solution Overview
Problem
Existing methods for virtual fitting of spectacle frames require manual marking of points on a 3D head model, which is time-consuming and prone to errors, especially when using optimization methods like the Levenberg-Marquardt algorithm, which may get stuck in local minima and require significant computational resources.
Innovation Solution
A method that automates the definition of measurement points on a 3D head model by fitting a parametric head model and determining these points based on second measurement points defined on the parametric model, allowing for efficient fitting of spectacle frames without manual user input or image analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual marking of points on 3D head model is used, then measurement precision can be achieved, but time consumption and operational complexity increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-defining measurement points on a standardized reference head model before actual fitting. The system pre-calculates and stores the positions of anatomical landmarks (nose bridge, temples, ears, etc.) on a reference head, so that when a customer's head model is generated, these points can be automatically transferred through scaling and transformation without manual marking, thus achieving both precision and efficiency.
Solution Approach 2:
The patent uses copying by transferring measurement point positions from a reference head model to a customer-specific head model. The coordinates of measurement points defined on the reference head are copied and adapted to the customer's head model through geometric transformation based on scaling factors and rotation angles, eliminating the need for manual point marking while maintaining measurement accuracy.
2Manufacturing precision
If optimization methods like Levenberg-Marquardt algorithm are used, then fitting accuracy improves, but computational resources and time required increase
Solution Approach 1:
The patent applies preliminary action by pre-defining measurement points on a standardized reference head model before actual fitting. The system pre-calculates and stores the positions of anatomical landmarks (nose bridge, temples, ears, etc.) on a reference head, so that when a customer's head model is generated, these points can be automatically transferred through scaling and transformation without manual marking, thus achieving both precision and efficiency.
Solution Approach 2:
The patent uses copying by transferring measurement point positions from a reference head model to a customer-specific head model. The coordinates of measurement points defined on the reference head are copied and adapted to the customer's head model through geometric transformation based on scaling factors and rotation angles, eliminating the need for manual point marking while maintaining measurement accuracy.
3Measurement precision
If manual point marking and image analysis are required, then measurement accuracy can be achieved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent applies self-service by enabling the system to automatically generate customer-specific head models and determine measurement points without requiring manual user input or interaction. The system autonomously performs head model generation from 3D scans, scales the reference head model to match the customer's head dimensions, and transfers measurement points automatically, making the process user-friendly while maintaining high measurement accuracy.
4Measurement precision
If extensive image processing is performed, then measurement accuracy improves, but computational load and processing time increase
Solution Approach 1:
The patent applies preliminary action by pre-defining measurement points on a standardized reference head model before actual fitting. The system pre-calculates and stores the positions of anatomical landmarks (nose bridge, temples, ears, etc.) on a reference head, so that when a customer's head model is generated, these points can be automatically transferred through scaling and transformation without manual marking, thus achieving both precision and efficiency.
Data Source
AI summary
A method for virtual spectacle adjustment and a corresponding computer program and computing device are disclosed. First measurement points are defined on a 3D model of a person's head, and a model of a frame is adjusted on the basis of the first measurement points. Defining the first measurement points includes defining second measurement points on a parametric head model, adjusting the parametric head model to the 3D model of the person's head, and determining the first measurement points on the basis of the second measurement points and the adjustment. In this way, the second measurement points only have to be defined once on the parametric model so that the first measurement points can be defined for a plurality of different 3D models of different heads.