Video Extensometer

SA ASSOCIATES Video extensometer incorporates a high-resolution digital camera with advanced real-time image processing to make highly precise strain measurements of a variety of specimen types. 

The video extensometer determines the position of the markers through changes in the brightness of the light/dark edges of the markers.  The camera digitizes the image, and image analysis algorithms measure the change in grayscale along one image line on the specimen surface.  These algorithms allow the instrument to measure edge positions with sub-pixel accuracy. 

The measured values are transferred from the video extensometer to our tensile test machine through a digital interface.  SA ASSOCIATES tensile testing machine can then record and post process every measurement in the same way as other strain sensors or gauges. Typically the long travel extensometers have 800 mm of measurable field of view and offers an accuracy of up to +/- 0.025 mm on full scale or better.