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Theory and Background Knowledge

Core concepts and considerations for accurate DIC measurements. Topics include selecting appropriate subset sizes, step sizes, and strain filters; understanding projection error and strain tensor formulations; avoiding pitfalls when averaging angular data; validating DIC results against strain gauges; and optimizing hardware setup through proper lens selection and stereo angle configuration.

  • Why Don't I See Edge Data?

    In analysis, edge data can seem to be missing. This is due to analysis parameters and calculation methods. We have one data point for every subset. We report the data in the center of the subset. For ...

  • Surface Cracking

    Using DIC (digital image correlation) to measure cracking surfaces or breaking specimens can be a difficult task. The attached application note discusses some realities that must be considered when us...

  • Lens Selection and Stereo Angle

    Generally speaking, there are not many rules to setting up cameras, such as the stereo angle between cameras and lens selection because the calibration calculates all the parameters, such as stereo an...

  • Comparing 3D DIC Data to Theory/Strain Gauges/Other Techniques

     INTERPRETING 3D DIC DATA  Why does my strain or displacement data not match theory or other measuring techniques?  INTRODUCTION Digital Image Correlation (DIC) data is often used as a validation meth...

  • Comparing 2D DIC Data to Theory/Strain Gauges/Other Techniques

    INTERPRETING 2D DIC DATA Why does my strain or displacement data not match theory or other measuring techniques? INTRODUCTION Digital Image Correlation (DIC) data is often used as a validation method,...

  • Subset, Step Size and Strain Filter Selection

    Summary and Overview Here we will discuss subset size, step size and strain filter selection.  In short, you want your subset to be larger than your speckle sizes and for most applications your step s...

  • Speckle Pattern Fundamentals

    In digital image correlation, the quality of the data is often dependent on the quality of the speckle pattern.  Using an optimal speckle pattern is one of the most important factors in reducing measu...

  • Resolution and Accuracy

    System Specs Many things in our test set-up can affect our noise and resolution, but with a good setup, the following rules of thumb can be applied to estimate what type of noise and resolution you ca...

  • Projection Error: Explanation and Causes

    Introduction When running a correlation in Vic-3D, one of the values given for each image is the Projection error. This article will explain how the projection error is calculated and what can cause a...

  • Issues When Averaging Angle Values

    In Vic-2D and Vic-3D, some of the inspector tools will cause data to be averaged over a certain area - specifically, the Disc and Rectangle tools. With these tools, when the data is extracted, the res...