We investigate the optical absorption and scattering properties of underwater media pertinent to our underwater free space quantum key distribution (QKD) channel model. With the vector radiative transfer theory and Monte Carlo method, we obtain the attenuation of photons, the fidelity of the scattered photons, the quantum bit error rate, and the sifted key generation rate of underwater quantum ...

The objective of this paper is to present a downsized prototype of an Autonomous Underwater Vehicle (AUV) designed with the idea of dealing with cooperative tasks involving multiple agents. The entire system has been designed for marine and underwater environmental surveillance and protection. The agents provide an interesting point in the surveillance of shallow coastal waters and shallow wate...

This article presents an empirical model for the noise of the acoustic underwater channel in shallow water from the analysis of field data measurements. A probability density function for the noise amplitude distribution is proposed and the associated likelihood functions are derived. As a result, an expression to the probability of symbol error for binary signaling is presented for the channel...

In this paper a novel algorithm has been designed to get rid of the problem of over-enhancement found in Mix CLAHE specifically for underwater images. The underwater image is suffering from low contrast and resolution because of dispossessed visibility circumstances, hence a subject identification become typical task. The processing of underwater image captured is important because the grade of...

History of underwater diving dates back to antiquity. Breath-hold technique in diving was known to the ancient nations. However, deep diving progressed only in the early decades of the 19th century as the result of advancements in efficient underwater technologies which subsequently led to invention of sophisticated sets of scuba diving in the 20th century. Currently, diving is performed for va...

Deployment efforts of underwater acoustic sensor networks have been impeded by the prohibitive monetary cost and high power consumption of existing acoustic hardware, which typically targets deep water long range communication. To address this issue, we propose software-driven underwater networks that rely on widely available speakers and microphones in electronic devices, coupled with software...

This paper designs an underwater acoustic communication system based on tamed spread spectrum and Frequency Hopping Multiple Access (FHMA) for multiple underwater vehicles. In this system, multiple underwater vehicles can communicate with the console on the water surface simultaneously successfully. The communication system is composed of tamed spread spectrum modulation and demodulation, frequ...

Underwater vision is a significant issue in ocean engineering. Atmospheric images and underwater images undergo from medium scattering and light distortion, leading to the low contrast and visibility of images. However, there are some different characters of the underwater images. Firstly, catching pictures submerged is troublesome, because of the weakening caused by light that is reflected fro...

In underwater computer vision, images are influenced by the water in two different ways. First, while still traveling through the water, light is absorbed and scattered, both of which are wavelength dependent, thus create the typical green or blue hue in underwater images. Secondly, when entering the underwater housing, the rays are refracted, affecting image formation geometrically. When using...