The interest in research on underwater wireless communication has been growing among both civilian and military organizations. This is due to the increasing use of submergedactions, that are military surveillance, submerged mining, fiber optic and pipeline installation, and aquatic/biological research. Researchers in fields like marine biology, engineering, and other disciplines require tools to better understand the underwater environment, as it covers over 71% of the earth's surface(Halakarnimath and Sutagundar 2021). A robust underwater acoustic communication infrastructure is necessary for the growth of undersea operations.
The underwater environment is one of the most challenging for communication, due to factors such as slow propagation, limited bandwidth, and large multipath delay spread. Two wireless communication methods that can be used underwater are electromagnetic and auditory. Electromagnetic waves are employed when sending over an electromagnetic medium, while acoustic waves are used when transmitting over an acoustic medium(Lv et al. 2022). Acoustic waves are created by the vibration of particles and are better suited for communication underwater due to their physical properties. Electromagnetic waves, on the other hand, require enormous power and large antenna diameters to work in the low frequencies that are possible underwater, making them a costly alternative.The underwater environment presents unique challenges for communication, including slow propagation, limited bandwidth, and large multipath delay spread(Reid et al. 2018). In order to effectively communicate underwater, specialized techniques are required to account for these challenges. One example of an underwater acoustic communication situation is shown in Fig. 1, in which an underwater audio communication system is being used.
The majority of researchers in underwater acoustic communication use auditory communication because it consumes less power(Park et al. 2022). It has been found that interactions at the water-air interface may be mediated by electromagnetic waves instead of acoustic waves. UWA communication is used in diverse fields, including oceanography, maritime commercial activities, the military, and the offshore oil sector. However, the wireless acoustic signal propagation over a water body is significantly impacted by the marine or underwater environment, leading to problems like Doppler shift, multipath propagation, high attenuation, constrained bandwidth, severe fading, prolonged delay spread, rapid temporal channel change, route loss, and noise(Hemavathy and Indumathi 2021).
To develop and enhance efficient underwater acoustic communication systems, it is crucial to conduct research and have a thorough understanding of how the underwater environment affects communication signals(Cui et al. 2023). One method for replicating the effects of the underwater acoustic channel on the channel is to replicate the characteristics of the actual aquatic environment(Huang et al. 2020). Channel modeling is complex due to differences in completespeed, the coarseness of the marine floor, multipath acoustic signal transmission, and background ocean sounds caused by aquatic life and human activity. Several underwater acoustic channel models have been developed using mathematics, with the BELLHOP model being commonly used in UWA communications channel modeling.Another important aspect in underwater acoustic communication is image processing, which plays a vital role in underwater surveillance, navigation and remote sensing. Image processing techniques can be used to enhance the visibility of underwater images, remove noise and improve the accuracy of object detection(Pandiyan et al. 2022). These techniques are often used to extract useful information from underwater images and videos, such as object recognition, target tracking, and feature extraction.In addition to traditional image processing techniques, there are also specialized techniques that are specific to underwater images. These techniques include color correction, which compensates for the loss of color due to water absorption, and dehazing, which removes the turbidity caused by small particles suspended in the water(Han et al. 2019).
Another important aspect of underwater image processing is the use of computer vision algorithms. These algorithms can be used to detect and classify objects in underwater images and videos, as well as to track their movement over time. This is especially useful in applications such as underwater surveillance, where real-time detection and tracking of objects is necessary(Rathor and Agrawal 2021).Some of the most recent developments in underwater image processing include the use of deep learning algorithms, which have been shown to be very effective in object detection and classification tasks. These algorithms are trained on large datasets of underwater images and can be used to automatically detect and classify objects in real-world underwater images and videos(Zhang et al. 2022).
In conclusion, underwater wireless communication and image processing are important fields of research that have been gaining increasing attention in recent years(Jha et al. 2022; Rahmeni et al. 2022). The unique challenges of the underwater environment, such as slow propagation, limited bandwidth, and high attenuation, require specialized techniques for communication and image processing. The use of advanced techniques such as deep learning and computer vision algorithms are promising areas of research that are expected to lead to significant advancements in the field shortly. In this article, the first machine learning techniques used in acoustic signals are addressed, followed by results of machine learning techniques, and the second edge detection method of underwater image processing is discussed with results.