Temporal Analysis of Speckle Images in Full-Field Interferometric and Camera-Based Optical Dynamic Measurement

Abstract

Vibration measurement is crucial in fields like aviation, aerospace, and automotive engineering, which are trending towards larger, lighter, and more complex structures with increasingly complicated dynamics. Consequently, measuring a structure’s dynamic characteristics has gained heightened importance. Among non-contact approaches, those based on high-speed cameras combined with laser interferometry or computational imaging have gained widespread attention. These techniques yield sequences of images that form a three-dimensional space-time data set. Effectively processing these data is a prerequisite for accurately extracting dynamic deformation information. This paper presents two examples to illustrate the significant advantages of signal processing along the time axis in dynamic interferometric and digital speckle-image-based dynamic measurements. The results show that the temporal process effectively minimizes speckle and electronic noise in the spatial domain and dramatically increases measurement resolutions.

Keywords

• laser Doppler vibrometer
• digital image correlation
• laser interferometry
• high-speed imaging
• temporal processing