Preprocessing of raw data for quality enhancement of the pointwise dynamic speckle analysis

Elena Stoykova

doi:10.1117/12.2319495

7 September 2018 Preprocessing of raw data for quality enhancement of the pointwise dynamic speckle analysis

Elena Stoykova

Proceedings Volume 10834, Speckle 2018: VII International Conference on Speckle Metrology; 108341O (2018) https://doi.org/10.1117/12.2319495
Event: SPECKLE 2018: VII International Conference on Speckle Metrology, 2018, Janów Podlaski, Poland

Abstract

The pointwise intensity-based processing of time-correlated speckle patterns allows for detection of activity in threedimensional objects by building a two-dimensional map of a certain statistical parameter. We have developed in this work reliable approaches for high-quality visualization of the activity map through normalization and preprocessing of the captured raw data. As a first task, we analyzed statistical behavior of correlation-based estimates to show erroneous determination of activity under non-uniform illumination or varying reflectivity across the object surface for nonnormalized algorithms and wrong detection of zero-activity regions for the normalized algorithms. Next, we proposed solution for the non-uniform illumination issue by using the sum of the speckle patterns at a given time lag for normalization and by introducing a flexible threshold to form binary patterns. We checked the option of the spatial smoothing of the raw data for activity map visualization enhancement and proved that smoothing in the temporal domain was more effective. Efficiency of the proposed preprocessing for data captured at uniform and non-uniform illumination was demonstrated on synthetic and experimental speckle patterns.

Citation Download Citation

Elena Stoykova "Preprocessing of raw data for quality enhancement of the pointwise dynamic speckle analysis", Proc. SPIE 10834, Speckle 2018: VII International Conference on Speckle Metrology, 108341O (7 September 2018); https://doi.org/10.1117/12.2319495

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