Direct physical modelling and scene reconstruction in order to assess the performance from a new concept of active imaging: Mosaic active imaging system

Emmanuelle Thouin (1) , Marie-Thérèse Velluet (2) , Dominique Hamoir (1) , Laurent Hespel (2) , François Malgouyres (3) , Xavier Briottet (1)

1 ONERA - The French Aerospace Lab [Toulouse]
2 ONERA - The French Aerospace Lab [Châtillon]
3 IMT - Institut de Mathématiques de Toulouse UMR5219

Active imaging can be used for surveillance or target identification at long range and low visibility conditions. Its principle is based on the illumination of a scene with a pulsed laser which is then backscattered to the sensor. The signal to noise ratio and contrast of the object over the background are increased in comparison with passive imaging. Even though, range and field of view (FOV) are limited for a given laser power. A new active imaging system presented here aims at overcoming this limitation. It acquires the entire scene with a high-speed scanning laser illumination focused on a limited region, whereas at each scan the full frame active image is acquired. The whole image is then reconstructed by mosaicking all these successive images. A first evaluation of the performance of this system is conducted by using a direct physical model. This end-to-end model, realistic in terms of turbulence effects (scintillation, beam wandering ...), gives us a sequence of images a synthetic scenes. After presenting this model, a reconstruction method of the total scene is described. And the performances of this new concept are compared to those of a conventional flash active camera by using usual metrics (SNR, MTF ...). For various mean laser powers, we quantify the gains expected in terms of range and field of view of this new concept.

Mots clés: Active Imaging; laser imaging; image reconstruction; physical modelling; optimization problem

Domaines: Optimisation et contrôle [math.OC]

Emmanuelle Thouin, Marie-Thérèse Velluet, Dominique Hamoir, Laurent Hespel, François Malgouyres, et al.. Direct physical modelling and scene reconstruction in order to assess the performance from a new concept of active imaging: Mosaic active imaging system. 10th International IR Target and background modeling & simulation workshop, 2014, Ettlingen, Germany. ⟨hal-01486854⟩