High-Speed Deformation Measurement with Event-Based Cameras

BackgroundHigh-speed strain field measurement based on digital image correlation (DIC) is limited by high equipment cost and large transmission bandwidth requirements for high-speed cameras. Emerging event-based cameras offer microsecond time resolution and low power consumption, generate events by asynchronously detecting illumination intensity changes at each pixel, have potential for applications in high-speed strain field measurements as a low-cost solution.ObjectiveUsing an event camera to directly capture a deformation process has some limitations, including motion blur, unclear images, and uneven gray scale quantization. This paper proposes a new method to avoid the above limitations.MethodsA strobe light is used to assist image reconstruction for event cameras. Event cameras can generate events using a strobe light to illuminate the object with white speckle on black background, to obtain a speckle image at a specific moment, and then use DIC to obtain the displacement and strain fields.ResultsValidation experiments were performed, capturing 2D displacement and strain fields at 1000 frames per second with 1280 x 800 pixel resolution, and DIC matching error = 0.4 pixels.ConclusionsThis paper introduces a novel using strobe lighting to assist image reconstruction for event cameras. This technique presents a cost-effective alternative for high-speed deformation measurements, bypassing the constraints of directly capturing the deformation process with an event camera. The proposed method exhibits remarkable adaptability to the motion speed of the object being measured, while maintaining high temporal resolution and low data redundancy.