Panoramic amplitude-fluctuation electronic speckle pattern interferometry system for inner vibration measurement

We propose a panoramic vibration measurement system for the inner cylindrical surface of an object based on amplitude fluctuation electronic speckle pattern interferometry and developed according to the Michelson interference configuration. A conical mirror, aligned to the axis of the inner cylindrical surface, is illuminated to transform a single camera view into a panoramic view. After transposing the observation coordinate system, a complete inner 360-deg vibration pattern can be reconstructed. The principle of transformation from a Cartesian-coordinate system to a cylindrical-coordinate system is introduced in detail. The panoramic vibration of the inner circular tube is determined, and the first six modes are analyzed. The comparison and error analysis of the proposed system with the ANSYS simulation results prove the accuracy and feasibility of the system.