Temporal correlations imaging fixed targets through turbulence

Area of Science:

• Optics and Photonics
• Atmospheric Physics
• Signal Processing

Background:

• Dynamic imaging through turbulent media is crucial for applications like remote sensing and astronomy.
• Understanding how atmospheric turbulence affects image temporal characteristics is essential for accurate data acquisition.
• Previous studies have explored spatial distortions, but temporal correlations require further investigation.

Purpose of the Study:

• To investigate the impact of atmospheric turbulence strength on temporal correlations in dynamic imaging.
• To quantify long-range temporal correlations using detrended fluctuation analysis.
• To analyze these correlations in high-contrast regions of images transmitted through turbulence.

Main Methods:

• Controlled laboratory experiments simulating atmospheric turbulence with varying refractive index structure constant (Cn2).
• Dynamic imaging of fixed high-contrast targets using incoherent light.
• Application of detrended fluctuation analysis (DFA) to pixel time series.
• Inclusion of scintillation information for each pixel in the analysis.

Main Results:

• Turbulence strength was found to generally increase temporal correlations in image time series.
• Long-range temporal correlations were successfully measured using DFA.
• The effect was most pronounced in pixels corresponding to high-contrast regions of the target.

Conclusions:

• Atmospheric turbulence significantly influences the temporal dynamics of images.
• Increased turbulence leads to enhanced temporal correlations, particularly in high-contrast areas.
• Detrended fluctuation analysis is a suitable method for characterizing these temporal effects in turbulent imaging.