Interpretation of the bacterial growth process based on the analysis of the speckle field generated by calibrated scattering media.

The speckle imaging technique has been proven to be a reliable and effective method for real-time monitoring of the growth kinetics of any bacterium in suspension. To understand the interaction between the light and the bacterial density, a simulation of the bacterial growth of Bacillus thuringiensis was performed using calibrated microspheres of different concentrations and sizes. Results show that the decrease of speckle grain size with the increase of the medium scattering coefficient reveals the two essential phases of the bacterial growth: the exponential phase where the number of the bacteria increases and the stationary phase where sporulation and cell lysis occur.

Assessing White Wine Viscosity Variation Using Polarized Laser Speckle: A Promising Alternative to Wine Sensory Analysis.

In this paper, we report measurements of wine viscosity, correlated to polarized laser speckle results. Experiments were performed on white wine samples produced with a single grape variety. Effects of the wine making cellar, the grape variety, and the vintage on wine Brix degree, alcohol content, viscosity, and speckle parameters are considered. We show that speckle parameters, namely, spatial contrast and speckle decorrelation time, as well as the inertia moment extracted from the temporal history speckle pattern, are mainly affected by the alcohol and sugar content and hence the wine viscosity. Principal component analysis revealed a high correlation between laser speckle results on the one hand and viscosity and Brix degree values on the other. As speckle analysis proved to be an efficient method of measuring the variation of the viscosity of white mono-variety wine, one can therefore consider it as an alternative method to wine sensory analysis.

Detection of an underwater target through modulated lidar experiments at grazing incidence in a deep wave basin.

The effectiveness of a pulsed radiofrequency modulated lidar and associated processing for underwater target detection at grazing incidence was experimentally assessed in a wave basin 50 m long and 20 m deep, under different conditions of swell produced within this facility to benefit from a controlled interface. This paper reports our experiments and offline data processing results, and describes significant improvements in the probability of detection that demonstrate the interest of using such a technique in this context.