Real-time image transmission through underwater wireless optical communication link for Internet of Underwater Things

The Internet of Underwater Things (IoUTs) can be considered as a potential candidate to interconnect physical devices (things) such as submarines, ships, divers, buoys, and unmanned underwater vehicles (AUVs) to collect and exchange information with each other in the ocean environment. Traditionally, sound waves have been used to transfer information between IoUTs, but due to the lack of limited bandwidth and data rate, the underwater wireless optical communication (UWOC)-based IoUTs can be considered as a viable solution. In this work, a real-time RGB image is transferred between two IoUTs using an intensity modulation direct detection (IM/DD) on-off keying (OOK) modulation scheme. To estimate the performance of the reconstructed image, structure similarity index (SSIM) and peak signal-to-noise ratio (PSNR) have been evaluated. During transmission of an image through the water, the quality of the received image degrades due to the absorption, scattering, and underwater turbulence which further limits the transmission range. Thus, to enhance the quality of the received images, two filters, that is, median and Wiener filters, have been proposed. The median filter improves the SSIM and PSNR of the reconstructed image more appropriately as compared to the Wiener filter. The results show that the proposed median filter can enhance the communication range of the UWOC point-to-point link by 100 m.