Hammoud Bilal, Daou Georges, Wehn Norbert
Microelectronic Systems Design Research Group, Department of Electrical and Computer Engineering, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany.
Department of Electrical and Computer Engineering, School of Engineering, Lebanese American University, Byblos P.O. Box 36, Lebanon.
Sensors (Basel). 2022 Feb 13;22(4):1431. doi: 10.3390/s22041431.
The need for oil spill monitoring systems has long been of concern in an attempt to contain damage with a rapid response time. When it comes to oil thickness estimation, few reliable methods capable of accurately measuring the thickness of thick oil slick (in mm) on top of the sea surface have been advanced. In this article, we provide accurate estimates of oil slick thicknesses using nadir-looking wide-band radar sensors by incorporating both C- and X-frequency bands operating over calm ocean when the weather conditions are suitable for cleaning operations and the wind speed is very low (<3 m/s). We develop Maximum-Likelihood dual- and multi-frequency statistical signal processing algorithms to estimate the thicknesses of spilled oil. The estimators use Minimum-Euclidean-Distance classification problem, in pre-defined multidimensional constellation sets, on radar reflectivity values. Furthermore, to be able to use the algorithms in oil-spill scenarios, we devise and assess the accuracy of a practical iterative procedure to use the proposed 2D and 3D estimators for accurate and reliable thickness estimations in oil-spill scenarios under noisy conditions. Results on simulated and in-lab experimental data show that M-Scan 4D estimators outperform lower-order estimators even when the iterative procedure is applied. This work is a proof that using radar measurements taken from nadir-looking systems, thick oil slick thicknesses up to 10 mm can be accurately estimated. To the best of our knowledge, the radar active sensor has not yet been used to estimate the oil slick thickness.
长期以来，为了能在短时间内控制损害，人们一直关注对溢油监测系统的需求。在油膜厚度估算方面，几乎没有能够精确测量海面厚油膜（以毫米为单位）厚度的可靠方法。在本文中，我们通过结合C波段和X波段，利用天底观测宽带雷达传感器，在天气条件适合清理作业且风速非常低（<3米/秒）的平静海面上，提供油膜厚度的准确估算。我们开发了最大似然双频和多频统计算法来估算溢油厚度。这些估计器在预定义的多维星座集中，基于雷达反射率值使用最小欧几里得距离分类问题。此外，为了能够在溢油场景中使用这些算法，我们设计并评估了一种实用的迭代程序的准确性，以便在有噪声的条件下，将所提出的二维和三维估计器用于溢油场景中准确可靠的厚度估计。模拟和实验室实验数据的结果表明，即使应用了迭代程序，M扫描4D估计器的性能仍优于低阶估计器。这项工作证明，利用从天底观测系统获取的雷达测量数据，可以准确估算高达10毫米的厚油膜厚度。据我们所知，雷达有源传感器尚未用于估算油膜厚度。
