Image-Free Optical Assistance Method for Impact Vibration Localization in Inertial-Based Hull Deformation Measurement

Large naval vessels are not strictly rigid bodies. Inertial matching measurements are often used to continuously measure hull deformation, thereby achieving a unified spatial reference for the entire ship to ensure the combat effectiveness of onboard weapons. However, during combat, the inertial measurement unit (IMU) is highly sensitive to impact vibration. This sensitivity induces attenuated interference signals, leading to significant steady-state errors or even divergence in inertial-based hull deformation measurements. Therefore, it is necessary to localize the position of the impact vibration, allowing for timely error correction in the inertial-based hull deformation measurement system. To address the challenge of impact vibration localization, this article proposes a method for locating hull deformation impact vibration using inertial measurement information in conjunction with optical assistance on ships equipped with advanced optical sighting systems. Furthermore, to ensure rapid and precise localization of the impact vibration localization in wartime, the method combines inertial information with single-pixel imaging (SPI), utilizing high-speed light field modulation to achieve image-free and high-speed optical sighting point coordinate acquisition in the Fourier domain under ultralow sampling rate conditions. By eliminating the need to reconstruct redundant information from complete images, this image-free optical assistance method effectively localizes inertial-based hull deformation impact vibration through the integration of inertial information. Experimental results demonstrate that the proposed method, with a sampling rate as low as 0.02% of whole image-based methods within the response time of 600 ms, can effectively perform rapid impact vibration localization in inertial-based hull deformation measurements without requiring full images. Additionally, the method exhibits strong noise resistance and good applicability, offering new insights for the combined optical and inertial hull deformation measurement on large naval vessels.