Measurement of liquid levels inside containers is an important task in a number of industrial and scientific processes. In applications such as fuel monitoring, pharmaceutical industries, wastewater treatment, and food processes, the knowledge of the liquid level is of primary concern. Furthermore, the advent of new technologies and a growing number of applications require exploration of new sensors and techniques aiming at content level measurement. Over the years, several methods have been proposed to achieve this objective with pros and cons according to the specific area. At first glance, those methods can be grouped in mechanical [1], capacitive [2], [3], electromagnetic [4], [5], acoustic [6], ultrasonic [7], optical fiber sensors [8], or self-mixing interferometry [9], among others. A relevant condition of these techniques is whether they are invasive or not; for instance, transducers or sensors attached to the container or even immersed in the liquid can be unacceptable in certain applications in the pharmaceutical or food processing industries. A brief description of the principle of operation of each technique is as follows.

中文翻译：

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使用光学干涉测量法和神经网络进行非接触式液位测量


容器内液位的测量是许多工业和科学过程中的一项重要任务。在燃料监测、制药工业、废水处理和食品加工等应用中，液位知识是首要关注的问题。此外，新技术的出现和越来越多的应用需要探索旨在内容水平测量的新传感器和技术。多年来，已经提出了多种方法来实现这一目标，根据具体领域各有利弊。乍一看，这些方法可以分为机械 [1]、电容 [2]、[3]、电磁 [4]、[5]、声学 [6]、超声波 [7]、光纤传感器 [8]、或自混合干涉测量[9]等。这些技术的一个相关条件是它们是否具有侵入性；例如，在制药或食品加工行业的某些应用中，连接到容器或什至浸入液体中的换能器或传感器可能是不可接受的。每种技术的操作原理的简要描述如下。