Dynamic speckle

The dynamic pattern shows then the changes that, if they are analyzed along time, represent the activity of the illuminated material.

It can be analyzed by means of several mathematical and statistical tools and provide numeric or visual information on its magnitude, the not well defined idea of activity.

Because the number of scattering centers is very high the collective phenomenon is hard to interpret and their individual contributions to the final result can not be inferred.

Light scattered with small Doppler shifts in its frequency beats on the detector (eventually the eye) giving rise to the slow intensity variations that constitute the dynamic of the speckle pattern.

Then, the complete interpretation of the activity of a sample, by means of dynamic speckle, presents itself big challenges.

Biospeckle laser image sequence of a maize seed.
Generalized differences of a corn seed with pseudo-colors representing the level of activities, with high activity represented by red, and low activity represented by blue.