DIGITAL IMAGE CORRELATION SETUP

 

Digital Image Correlation (DIC), is an optical non contact method, used to acquire displacements by tracking a unique distribution of pixel intensities of a grey scale image called a pattern or template. These patterns are correlated over a series of camera obtained

 

 

Images of the object in concern to give the pixel displacement of the surface in two dimensional images which can be interpreted according to the three dimensional motion. This method is highly utilised when the object is too light, too small, having variation in temperature or working at high speeds, which prevents the use of traditional contact methods.

2D (for In plane deformation) & 3D DIC (for out of plane deformation) are commonly used in structural dynamic testing and in experimental mechanics specially fracture. Two or more cameras of high specification and resolution are employed in stereo-vision system principle in order to acquire 3D location of the points while single camera is employed for in plane testing.

 

DIC Cameras

 

 

The Stereo Vision DIC requires images obtained by both cameras simultaneously. High speed cameras are preferable for accurate measurement. Olympus i-speed TR cameras are being used in the experiment which has the ability to synchronise both the cameras at a time using a trigger.

 


Speckle Pattern on Membrane

 

 


2D DIC setup for Fracture Test