Liquid Lens Synchronization for Precise Rolling-Shutter Profilometry
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Solution Overview
Problem
Existing optical profilometry systems face challenges in accurately determining the laser line position due to limitations in camera resolution, lens sharpness, laser speckle, and laser spot width, especially when dealing with varying depths and moving subjects.
Innovation Solution
The integration of a liquid lens synchronized with a rolling shutter camera, utilizing a Scheimpflug configuration, allows for precise adjustment of the laser beam waist to match the camera's imaging sequence, ensuring optimal focus and alignment throughout the field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional optical system with fixed focus is used, then the system structure is simple, but the laser spot size varies with depth causing measurement errors
Solution Approach 1:
The patent implements dynamic focus adjustment by synchronizing the liquid lens focal length changes with the rolling shutter camera's depth scanning. The liquid lens continuously varies its focal length to maintain laser focus at different depths, transforming a static optical system into a dynamic one that adapts to varying measurement distances.
Solution Approach 2:
The liquid lens changes its optical parameters (focal length) in real-time based on the depth information from the rolling shutter camera. By adjusting the lens curvature and focal length dynamically, the system maintains optimal laser spot size and focus across varying depths, directly improving measurement precision.
2Measurement precision
If a rolling shutter camera is used for depth scanning, then depth resolution is improved, but synchronization with laser focus is difficult causing measurement errors
Solution Approach 1:
The system uses the rolling shutter camera's depth information as feedback to control the liquid lens focal length. The camera continuously provides depth data, and this information feeds back to adjust the liquid lens in real-time, creating a closed-loop synchronization system that maintains accurate focus-depth correspondence.
Solution Approach 2:
The liquid lens focal length is adjusted in advance based on predicted depth changes from the rolling shutter scan. By pre-synchronizing the focus adjustment with the anticipated depth variations, the system ensures that focus is already optimized when the laser reaches each depth level, reducing measurement errors.
3Adaptability or versatility
If laser focus is adjusted for varying depths, then measurement accuracy across different standoff distances improves, but the system complexity increases
Solution Approach 1:
The patent replaces traditional mechanical focus adjustment mechanisms (such as moving lenses or mirrors) with a liquid lens that uses electrical control to change focal length. This substitution eliminates complex mechanical components while achieving the same focus adjustment function, improving adaptability without proportionally increasing complexity.
Solution Approach 2:
The liquid lens serves multiple functions: it adjusts focus for varying depths, maintains optimal laser spot size, and synchronizes with the rolling shutter camera's depth scanning. This multi-functional component replaces what would otherwise require separate mechanical focus adjustment and depth coordination systems, improving versatility while controlling overall complexity.
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
This synchronization results in a consistently smaller and more precise laser spot or line, improving measurement accuracy and reducing errors across varying standoff distances, enabling precise optical profilometry.
Implementation Method 1
a liquid lens placed in a path of the laser, wherein the liquid lens is synchronized to the rolling shutter camera
Data Source
AI summary
An optical sensor system comprises a rolling shutter camera, a laser, and a liquid lens placed in a path of the laser, wherein the liquid lens is synchronized to the camera. A related method for synchronized optical profilometry comprises providing a camera, providing a laser beam source, providing a liquid lens, and synchronizing the liquid lens to the camera. A computer program product is also provided.