Wavefront Sensor Centroid Tracking Algorithm

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Solution Overview

Problem

Current wavefront sensors face challenges in achieving real-time wavefront sensing due to increased processing time caused by the growing number of centroids, which hinders efficient analysis and representation of dynamic aberration data in the human eye.

Innovation Solution

Implementing two different algorithms for centroid detection, where a first algorithm determines initial centroid positions and a second, faster algorithm tracks incremental changes within a predetermined vicinity of previously determined centroids, reducing processing time and data volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of centroids is increased to provide higher resolution wavefront sensing, then measurement precision is improved, but processing time increases

Engineering Contradiction:
Improvewavefront sensing resolutionVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing lookup tables that map centroid positions to wavefront coefficients. During real-time operation, the system performs rapid table lookups instead of executing complex mathematical computations, thereby maintaining high measurement precision with significantly reduced processing time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating pre-computed lookup tables that store the results of complex wavefront reconstruction calculations. These tables are generated in advance and copied into memory, allowing the system to retrieve pre-calculated wavefront coefficients instantly during real-time centroid analysis without repeating the computationally intensive reconstruction algorithms.

Inventive Principle:
Principle #26Copying

2Productivity

If real-time wavefront sensing is implemented to capture dynamic aberration changes, then productivity is improved, but processing complexity increases

Engineering Contradiction:
Improvereal-time data analysis speedVSAvoidprocessing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system performs preliminary computation by pre-calculating the relationship between centroid positions and Zernike polynomial coefficients and storing these relationships in lookup tables. This eliminates the need to execute complex reconstruction algorithms in real-time, enabling high-speed wavefront sensing while keeping the real-time processing logic simple.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical computation system with a data retrieval system. Instead of executing mathematical algorithms in real-time, the system substitutes complex computational mechanics with simple table lookup operations, dramatically reducing processing complexity while maintaining real-time performance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2252195B1Fast algorithm for streaming wavefront
Publication Date: 2018.06.06 BAUSCH & LOMB INC
  • EP2252195B1 patent drawingFigure 1~2a
  • EP2252195B1 patent drawingFigure 2b~3a
  • EP2252195B1 patent drawingFigure 3b~3c

AI summary

The invention is generally directed to the field of image processing, and more particularly to a method and an apparatus for determining a wavefront of an object, in particular a human eye. The invention discloses a method and an apparatus for real-time wavefront sensing of an optical system utilizing two different algorithms for detecting centroids of a centroid image as provided by a Hartmann-Shack wavefront sensor. A first algorithm detects an initial position of all centroids and a second algorithm detects incremental changes of all centroids detected by said first algorithm.