Coherent Light Vibration Detection via Speckle Analysis
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Solution Overview
Problem
Current vibration sensing methods, such as speckle interferometry, require scanning the target to detect small vibrational motions, which is time-consuming and inefficient for capturing vibrations across an entire scene.
Innovation Solution
A system utilizing a coherent light source to illuminate a scene, an optical unit to focus scattered light onto a pixelated detector, and a processing unit to analyze pixel intensity signals to derive a vibration spectrum across the entire field of view, eliminating the need for scanning by integrating speckle patterns from multiple elements onto corresponding pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If speckle interferometry is used to detect small vibrational motions, then measurement precision is improved, but productivity deteriorates due to time-consuming scanning
Solution Approach 1:
The patent segments the scene into multiple regions of interest (ROIs) and processes speckle patterns from different ROIs simultaneously using parallel computational methods. This allows vibration detection across the entire scene without sequential scanning, maintaining high measurement precision while dramatically improving productivity by processing multiple spatial locations concurrently.
Solution Approach 2:
The patent transitions from traditional point-by-point scanning in one dimension to parallel processing across two spatial dimensions by capturing the entire speckle pattern field of view. By analyzing speckle correlations across the full 2D scene simultaneously, the system achieves both high precision vibration detection and full-scene coverage without scanning time penalties.
2Measurement precision
If the camera is focused on a plane far from the target position to achieve high gain, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces a computational intermediary that processes speckle pattern correlations to extract vibration information. Instead of relying solely on optical focusing geometry, the system uses computational algorithms to analyze speckle pattern variations, thereby achieving high measurement precision without requiring complex optical arrangements or specific focus plane configurations.
Solution Approach 2:
The patent replaces the mechanical/optical focusing mechanism with a computational approach. Rather than adjusting optical focus planes to achieve sensitivity, the system uses digital signal processing of speckle patterns to detect vibrations, substituting mechanical/optical complexity with computational simplicity while maintaining or enhancing measurement precision.
3Measurement precision
If laser speckle interferometry is used to detect vibrations, then measurement precision is improved, but loss of time increases due to sequential processing
Solution Approach 1:
The patent implements continuous vibration monitoring by processing speckle patterns from the entire scene in parallel without interruption. The system continuously captures and analyzes speckle patterns across all regions of interest simultaneously, maintaining uninterrupted vibration detection and eliminating the time losses associated with sequential scanning or frame-by-frame processing.
Solution Approach 2:
The patent performs preliminary computation by pre-calculating speckle correlation functions and vibration spectra from captured patterns. By preparing computational kernels and correlation data in advance, the system reduces real-time processing requirements, enabling rapid vibration analysis while maintaining high spectral accuracy across the entire scene.
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
Enables simultaneous quantitative measurements of vibrations across the entire scene, providing a map of vibration amplitudes and frequencies, and enhancing sensitivity through the use of a spatially patterned mask to increase the modulation-to-DC ratio, thereby improving the detection of vibrational motions.
Implementation Method 1
The scattering of different portions of the light beam from the rough surface results in a random shift of the phases of the portions of the corresponding light waves and a random distribution of the intensities thereof. Consequently, the beam portions scattered from different surface portions interfere with each other, resulting in a light distribution with varying intensity in space.
Implementation Method 2
a camera is used to capture the speckle pattern formed by the scattering of coherent light (usually a laser) from a diffusive target
Implementation Method 3
an optical unit configured to focus scattered light from the scene onto a pixelated detector
Data Source
AI summary
Systems and methods are provided for vibrations detection in a scene. Systems comprise at least one coherent light source configured to illuminate the scene, an optical unit configured to focus scattered light from the scene onto a pixelated detector, the detector configured to provide pixel intensity signals, and a processing unit configured to analyze the pixel intensity signals over the pixels of the detector to derive a vibration spectrum of elements in the scene that correspond to the pixels. The signal modulation at each pixel may be used to indicate the vibrations of the scene element(s) that corresponds to the pixel(s). Vibration information concerning the scene may be used to direct other methods of vibration measurements, such as speckle interferometry, according to derived vibration images of the scene.