Principle of Digital Image Correlation

Digital Image Correlation (often referred to as “DIC”) is an easy to use proven optical method to measure deformation on an object surface. The method tracks the gray value pattern in small neighborhoods called subsets (indicated in red in the figure below) during deformation. Digital Image Correlation has been proven over and over to be accurate when compared to valid FEA models. The commercially available VIC-2D and VIC-3D systems from Correlated Solutions both utilize this advanced optical measurement technology.

 

Digital Image Correlation Overview

Below are the reasons why its versatility, robustness, and ease of use make it the only choice when it comes to digital image correlation.

DIC

Two-dimensional Example

The two pictures below show a speckle pattern on an aluminum sample with two offset semi-circular cut-outs. The two pictures were taken from an animation with the left image taken from the beginning and the right picture taken from the end of the animation. Since the deformation is predominantly in-plane, a single camera can be used to measure the deformation.

VIC2D

Small Deformation

VIC2Da

Large Deformation

The pictures below show the horizontal strain measured by two-dimensional image correlation for the pictures shown above.

VIC2D-2 VIC2D-2a
VIC2D-2b


Three-dimensional Example

The two speckle images below were taken simultaneously with the left and right camera of a stereo-system. The sample itself is a piece of glass with the company logo sticker adhered to the surface.  The speckle pattern was applied using standard off-the-shelf flat white and black spray paint.  Can you make out the shape?

VIC3Dleft

Left View
VIC3Dright

Right View

The plot below shows the shape of the logo sticker measured with the VIC-3D System. The thickness of the logo sticker is approximately 0.003″ or 0.070mm.

VIC3D-2