โ Scribed by Vittorio Murino; Andrea Trucco
No coin nor oath required. For personal study only.
This article describes a probabilistic technique for the have limited application, as they present a limited range and restoration of underwater acoustic images that is based on the Marcannot be used in turbid water. Instead, beyond use in any kind kov random fields (MRFs) methodology. The beamforming is applied of water condition and a longer-range capability, the acoustical to rough acoustic data that derive from multibeam systems or acoussystems are able to extract three-dimensional (3D) distance infortic cameras to build a three-dimensional (3D) map, that is associated mation about the objects that are present in a scene.
point by point with the estimates of the reliability of such measures.
Specifically, backscattered echoes that are received by a 2D array acoustic images: physical lens systems, beamforming (BF) sysantenna are arranged to generate two images in which each pixel tems, and holographic systems [1]. The BF is the most widely represents the distance (range) from the sensor plane and the confidence of the measures, respectively. Unfortunately, this kind of image used technique to form 3D acoustic images as a high frame rate is affected by several problems due to the nature of the signal and that can be obtained, light sensorial devices can be used and the the related sensing system. In the proposed algorithm, the range images have good quality [1,2]. To form an acoustic image, the and the confidence images are modeled as separate MRFs whose beamformer combines linearly the signals that are received by a associated probability distributions embed knowledge of the acoustic 2D array antenna. These signals represent the backscattered echsystem, of the considered scene, and of the noise affecting the meaoes from a scene that has previously been insonified by a coherent sures. In particular, the confidence image is first restored and the pulse [Fig. 1(a)]. The output of the beamforming is a time signal, result is used to reconstruct the 3D image to allow an active integracalled a beam signal, representing the backscattered echoes that tion of the reliability information. Optimal (in the maximum a posteriori probability sense) estimates of the reconstructed 3D map and the are generated by a scene in a specific direction. Detecting the restored confidence image are obtained by minimizing the energy temporal instant corresponding to the highest peak of the signal functionals, using simulated annealing. Experimental results on synenvelope, it is possible to estimate the distance of the scene in thetic and real images show the performance of the proposed that direction [2]. Iterating this mechanism with a set of regular approach.
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