The Virtual Frame Technique (VFT): direct imaging of fast cracks in soft elastomers

Many phenomena of interest in nature and industry are rapid, making direct imaging both challenging and cost-prohibitive. Dynamic cracks can propagate at the sound speed of a material and are ubiquitous in the earth sciences and engineering applications; thus fracture epitomizes such phenomena. In soft materials, the sound speed is of order several meters per second, and a dynamic crack will entirely rupture a cm-scale sample in about 10 msec requiring rapid imaging for direct visualization. Here we present the Virtual Frame Technique (VFT), a simple, useful, and accessible form of compressed sensing that leverages the dynamic range of the camera’s sensor to increase the frame acquisition rate by up to 6 orders of magnitude. We discuss the requirements for use of the VFT and its performance when employed with several commercially available conventional and high-speed cameras. Even Modern cell phones can achieve imaging rates of over a million fps using the VFT.