Local Wavelength Estimation with Synchronized Stroboscopic Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Full-field coherent optical imaging techniques face challenges in tracking wave propagation due to a limited field of view and high-speed waves, requiring high-power light sources or sensitive cameras to achieve sufficient Signal to Noise Ratio (SNR) during short exposure times.
Innovation Solution
A method for estimating local wavelength using full-field coherent optical imaging, involving synchronized periodic mechanical or thermal modulation with a series of periodic pulses, acquiring multiple images with controlled time delays, and applying noise-correlation-inspired reconstruction to estimate local wavelength without needing high-power light sources or sensitive cameras.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full-field coherent optical imaging techniques are used to track wave propagation, then high resolution imaging at micron scale is achieved, but the field of view is reduced making it difficult to track waves when wavelength exceeds field of view or wave travels at high speed
Solution Approach 1:
The patent employs a stroboscopic approach with periodic illumination pulses synchronized to the wave frequency. By illuminating the sample at specific time intervals during wave propagation, the system captures multiple phases of the wave cycle, enabling tracking of high-speed waves and wavelengths larger than the field of view while maintaining high spatial resolution.
2Productivity
If stroboscopic approach is used to follow periodic wave propagation, then wave tracking is enabled, but high-power light sources or very sensitive cameras are required to achieve sufficient Signal to Noise Ratio during short exposure time
Solution Approach 1:
The system uses periodic illumination pulses synchronized with the wave frequency, allowing accumulation of signal over multiple cycles. This synchronization enables the use of lower power light sources while maintaining sufficient signal-to-noise ratio by integrating information from multiple wave periods rather than requiring extremely short high-power pulses.
Solution Approach 2:
The stroboscopic method continuously illuminates the sample at regular intervals synchronized to the wave frequency, maintaining continuous data acquisition over multiple wave cycles. This continuous periodic action allows signal accumulation and averaging, improving signal-to-noise ratio without requiring peak high-power illumination.
3Measurement precision
If stroboscopic approach with high-power light source is used, then sufficient Signal to Noise Ratio is achieved during short exposure time, but the approach is limited in terms of exposure time to illumination power ratio
Solution Approach 1:
By using periodic illumination synchronized to the wave frequency, the system can use longer exposure times per pulse while maintaining adequate signal-to-noise ratio. The synchronization allows signal accumulation over multiple cycles, reducing the need for extremely high peak power and providing more flexible exposure time parameters.
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 tracking of wave propagation in enlarged frequency and speed domains, allowing real-time analysis of mechanical or thermal waves with high resolution and reduced equipment requirements.
Implementation Method 1
full-field coherent optical imaging techniques... provide direct access to the phase and have a sensitivity of a few nanometers
Implementation Method 2
full-field coherent optical imaging techniques... speckle imaging, digital holography or full-field optical coherence tomography
Implementation Method 3
wave propagation velocity has been widely used... to assess the elastic and viscoelastic mechanical properties of human soft tissues
Implementation Method 4
periodic mechanical stress or to a periodic thermal modulation
Implementation Method 5
One solution to this problem is to use a stroboscopic approach that allows the propagation of periodic waves to be followed
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method for estimating a local wavelength within a sample submitted to a periodic mechanical stress, comprising the following steps: A) acquiring at least N images of the sample by full-field coherent optical imaging, where N ≥ 3, for each integer k from 1 to N, acquiring a kth image of the sample while said sample is submitted to said periodic mechanical stress as follow: A1) launching acquisition of the kth image, A2) concurrently to the launching of acquisition of the kth image, generating a periodic mechanical stress, of period T, on the sample, A3) with a given time delay τk = τ1 + (k-1)*τoffset with respect to the launching of acquisition of the kth image where τoffset is a time offset, illuminating said sample with a series of periodic pulses, of period T, A4) stopping acquisition of the kth image after an acquisition time tACQ = n*T, where n ≥ 2, B) estimating the local wavelength by using the N images previously acquired.