Digital Image Correlation
DIGITAL IMAGE CORRELATION
Digital Image Correlation, often referred to as DIC, is a 2D or 3D optical tracking technique used to measure deformation, vibration and strain in materials. DIC tracks a gray value pattern in subsets through digital imaging. You will often see this speckled pattern on objects such as aluminum, rubber, glass, and plastics. This technique is used for a variety of tests including torsion, tinsel, bending, or load testing. DIC can be used on very small or large testing areas.
For two-dimensional DIC tracking, a single high-speed camera can capture the deformation in a single plane. For three-dimensional DIC tracking, two high-speed cameras are need for simultaneous recording. By using multiple synchronized cameras along with DIC software, you can create 3D renderings of your object allowing you to enhance your visualization. Photron high-speed cameras are utilized by all DIC system integrators worldwide.
A camera’s minimum exposure time is often a critical factor in choosing a high-speed camera. Some very fast high-speed events require extremely short exposure times – sometimes even less than 1 microsecond – to stop the motion of those high-speed events. A camera’s ability to achieve a sub-microsecond exposure is dependent on two things. First, the camera’s sensor must be capable of performing such a short exposure. Second, the camera’s sensor must be sensitive enough that when it does utilize a sub-microsecond exposure it can capture enough photons of light during the exposure to be able to generate video that is of sufficient quality for analysis. A short exposure does no good if the end result is a sequence of images that are so dark that you cannot see what happened within the high-speed event.
Virtual Engineering Lab Using Photron High-Speed Cameras for Aviation Research
Wichita State University’s National Institute for Aviation Research (NIAR) is using high-speed digital cameras, manufactured by Photron, in their Virtual Engineering Laboratory in a variety of testing modes such as high-impact dynamic events.
Laboratory Director Gerardo Olivares uses Photron’s FASTCAM SA-Z models to capture high-resolution images of events that happen too fast for the eye to see. The SA-Z high-speed cameras capture up to 20,000 fps at full resolution of 1024 x 1024 pixels.