Unmanned underwater vehicles (UUVs) are widely used in marine environmental monitoring, underwater resource exploration, inspection, and cooperative operation. These applications require short-range underwater links with high transmission rates, high reliability, and strong anti-interference capability. In practical underwater systems, wireless charging and data transmission are often integrated on the same platform. Under this condition, conventional electromagnetic communication is easily affected by interference generated by wireless power transfer equipment, which limits transmission stability. By contrast, underwater wireless optical communication based on visible light offers advantages such as high bandwidth, low latency, and strong immunity to electromagnetic interference, making it suitable for short-range underwater transmission. However, in compact bidirectional underwater systems, local transmitting light sources may introduce backscatter self-interference, whereas the co-existence of communication and wireless charging modules may further cause electromagnetic coupling interference. To address these problems, this study proposes a visible light communication system for underwater wireless data transmission in UUVs under the co-existence of wireless charging and communication.

An underwater optical communication channel model is first established to analyze light propagation in water, with emphasis on scattering effects and backscatter self-interference in short-range transmission. Based on the channel characteristics, a combined interference suppression method is proposed. In the optical path, wavelength division is used to reduce mutual interference between transmitting and receiving channels, and narrowband optical filters are employed at the receiver to suppress undesired spectral components and weaken optical scattering interference. In the circuit and structural design, electromagnetic shielding is adopted to reduce the electromagnetic coupling interference introduced by the wireless charging system and surrounding electronic modules. On this basis, a miniaturized low-power bidirectional underwater visible light communication experimental system is implemented. The system employs an LED array as the optical transmitter and adopts a field-programmable gate array (FPGA) as the core digital processing platform for communication control and data processing. In addition, a packet loss retransmission mechanism based on the user datagram protocol (UDP) is introduced to improve transmission reliability in practical applications. Finally, experiments are carried out to evaluate the performance of the proposed system under the co-existence of underwater wireless charging and visible light communication.

The experimental results show that the proposed system can achieve stable short-range underwater wireless data transmission for UUVs in a complex interference environment. The combined optical-electrical interference suppression method effectively reduces the influence of optical backscatter and electromagnetic coupling interference, thereby improving the stability of signal reception and data recovery. Within a communication distance of 20 cm, the system achieves stable bidirectional transmission at a rate of 2 Mb/s, and the measured bit error rate is only 8.07×10^–7. The system maintains high transmission quality under the co-existence of wireless charging and communication. In addition, the UDP-based packet loss retransmission mechanism enhances the reliability of data transmission in practical applications. The experimental prototype also verifies the feasibility of miniaturized and low-power implementation, which is favorable for integration into compact underwater platforms.

By combining underwater channel analysis, wavelength-division light source design, narrowband optical filtering, electromagnetic shielding, and UDP-based packet retransmission, the proposed system improves communication reliability under wireless charging and data transmission. This study provides a practical reference for short-range high-speed underwater communication and energy-information collaborative transmission in UUV platforms.

Vibration measurement is a fundamental means to ensure the safety and good condition of structures. Highly accurate vibration measurements provide precise structural dynamic properties for applications such as structural design, installation and commissioning, and health management.

Compared with traditional vibration measurement methods, video-based vibration measurement is an emerging noncontact and full-field method with high spatial density, high flexibility, easy operation, and cost-effectiveness. Through the video-based vibration measurement method, the vibration displacement information of the measured structure can be obtained from a long distance, which enables the direct observation of small vibration patterns of the structure and has received extensive attention in recent years. Therefore, summarizing the research on video-based vibration measurement technology is of considerable theoretical and applied significance. In the field of video-based vibration measurement technology, the currently commonly used measurement methods mainly include three types, namely, digital image correlation, target tracking, and optical flow methods. The digital image correlation method can obtain accurate three-dimensional vibration information using a dual-camera system. The target tracking method can conduct vibration displacement measurements of large dynamic structures with reliable markers. The optical flow method is a type of target-less video-based vibration measurement method, which can be classified into the intensity and phase optical flow methods according to the different objects to be processed on the surface of the object being measured. The camera arrangement, installation, and operation requirements are low when the object to be measured is small or difficult to access. The emergence of video motion amplification technology further expands the response range of video-based vibration measurement methods, enabling surveyors to more intuitively, rapidly, and dynamically obtain an understanding of the state of small vibrations.

In recent years, with the continuous development of machine vision, artificial intelligence, and other technologies, future video-based vibration measurement methods are expected to achieve further breakthroughs in measurement accuracy, computing efficiency, and anti-interference capability. Video-based vibration measurement technology in the field of vibration measurement has unique advantages and practical value, has broad application prospects, and has attracted increasing attention from technicians and researchers. Video-based vibration measurement methods can not only provide new solutions to vibration measurement problems but will also become a powerful complement to traditional vibration measurement methods, particularly in the full-field measurement and dynamic visualization of the vibration. Video-based vibration measurement methods can undertake more important measurement tasks. With the further development of machine vision and optical technology, video-based vibration measurement methods will have broader application prospects as well as higher application value and research significance.