Augmented Lagrangian Digital Image Correlation and Tracking

2D-AL-DIC(Augmented Lagrangian DIC) is a fast, parallel-computing DIC algorithm which also considers global kinematic compatibility.

Augmented Lagrangian Digital Image Correlation (2D_ALDIC)

AL-DIC(Augmented Lagrangian DIC) is a fast, parallel-computing hybrid DIC algorithm, which combines advantages of local subset DIC method (fast computation speed, and parallel computing) and finite-element-based global DIC method (guarantee global kinematic compatibility and decrease noise).

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Advantages of AL-DIC algorithm

• [1] It’s a fast algorithm using distributed parallel computing.
• [2] Global kinematic compatibility is added as a global constraint in the form of augmented Lagrangian, and solved using Alternating Direction Method of Multipliers scheme.
• [3] Both displacement fields and affine deformation gradients are correlated at the same time.
• [4] No need of much manual experience about choosing displacement smoothing filters.
• [5] It works well with compressed DIC images and adaptive mesh. See our paper: Yang, J. & Bhattacharya, K. Exp Mech (2019). https://doi.org/10.1007/s11340-018-00459-y;
• [6] Both accumulative and incremental DIC modes are implemented to deal with image sequences, which is especially quite useful for very large deformations.
• [7] ALDIC application example -- uniaxial compression experiment: https://github.com/jyang526843/2D_ALDIC_v3/blob/master/Example_aldic_foam_compression_strain_eyy.gif
• [8] ALDIC is extended with adaptive quadtree mesh to solve complex geometry. Some examples: https://uwmadison.box.com/s/4n5hmf04rzp4la96bt2rcjk4f6o5d5nf

Prerequisites & Installation

AL-DIC MATLAB code was tested on MATLAB versions later than R2018a. Both single thread and parallel computing features are included in AL-DIC code. Please download and unzip the code to the MATLAB working path. Then, execute the mail file: main_ALDIC.m.

Code manual

Full size code manual is available at: https://www.researchgate.net/publication/344796296_Augmented_Lagrangian_Digital_Image_Correlation_AL-DIC_Code_Manual

Code demo videos

ALDIC Matlab code demo: (Youtube) https://www.youtube.com/watch?v=JctudMfO-7w (Bilibili) https://www.bilibili.com/video/BV1hf4y1i7bK/

I also attach my EASF webinar to introduce AL-DIC/DVC algorithm and review other DIC/DVC methods: (Youtube) https://www.youtube.com/watch?v=-t61WrVagZ4 (Bilibili) https://www.bilibili.com/video/BV1ff4y1B71L/

Citation

• [1] For full details, and to use this code, please cite our paper: Yang, J. and Bhattacharya, K. Augmented Lagrangian Digital Image Correlation. Exp.Mech. 59: 187, 2018. https://doi.org/10.1007/s11340-018-00457-0. Full text can be requested at: www.researchgate.net/publication/329456141_Augmented_Lagrangian_Digital_Image_Correlation
• [2] Yang, J. (2019, March 6). 2D_ALDIC (Version 3.3). CaltechDATA. https://data.caltech.edu/records/1443
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• [3] Yang, J. and Bhattacharya, K. Combining Image Compression with Digital Image Correlation. Exp.Mech. 59: 629-642, 2019. https://doi.org/10.1007/s11340-018-00459-y. Full text can be requested at: https://www.researchgate.net/publication/330489954_Combining_Image_Compression_with_Digital_Image_Correlation
• [4] Finite-element-based Global DIC code is also available at: https://www.mathworks.com/matlabcentral/fileexchange/82873-2d-finite-element-global-digital-image-correlation-fe-dic
• [5] Besides 2D-DIC, our new code "ALDVC" (augmented Lagrangian Digital Volume Correlation) to track deformations in volumetric images is also available: https://www.mathworks.com/matlabcentral/fileexchange/77019-augmented-lagrangian-digital-volume-correlation-aldvc

Contact and support

Jin Yang (Caltech solid mechanics, PhD '19): [e-mail] -or- [e-mail] I appreciate your comments and ratings to help me further improve this code. If you have other questions, feel free to email me.