Thanks for your interest in my DIC code. There are two principle displacement data files. The first, disp_raw_data.mat, is generated when you run “correlate_images_GUI”, and is a calculation of the displacements before any smoothing has been done. These displacements are in terms of pixels. The second, disp_smooth_data.mat, is generated when you run “compute_data_GUI.” These displacements are scaled and smoothed according to the parameters you set in “compute_data_GUI.”
To work with the raw displacements, type “load disp_raw_data” in the command window. Two variables, dispx_raw and dispy_raw, should now be in your workspace. These matrices are the horizontal (x) and vertical (y) displacements respectively. The rows of the matrices represent the control points from your correlation, and the columns represent the images that you correlated. For example, the x-displacements for image 5 would be the entire column 5 of dispx_raw.
Similarly, to work with the scaled and smoothed displacements, type “load disp_smooth_data” into the command window, and the two variables dispx_smooth and dispy_smooth will be in your workspace.
Please let me know if you have further questions.
I have been using your code for the last two weeks and it is great! Thanks a lot.
By the way, I would like to use the displacement matrix to calculate the error of the correlation (max error and average). How is the displacement matrix called in your code?
Thanks a lot
Thank you for your comments and suggestions. Most of the areas you suggest for improvement are parts of the code that I personally don’t use frequently (such as the delete_data_GUI, any stress calculations, correcting for rigid body motion in the displacements), and therefore they have not received as much attention as other portions of the code. You are always welcome to modify the code yourself, and if you’d like, I’d be happy to post any improvements to this site, so that other users can benefit as well.
Concerning your first comment, you need to be careful when performing multiple correlations on one set of images. You always need to set your working directory to the folder containing the images you wish to correlate, but after a correlation is complete, you can move all the data files generated during the correlation to a new folder. I recommend always starting a correlation with no files from previous correlations in the working folder. This will prevent you from seeing results from a previous correlation when you are trying to view results from a current correlation. Please let me know if you have further questions regarding this part of the code.
Thank you very much for this work, you've done a great job!
I just wanted to add some notes/questions as a "non-professional" user, so may be someone will have a time for code improvement. Or find what I've didn't.
1. When you want to see the full-image correlation results (after initial guess finding), Visualize_data_GUI shows the results of previous calculations. So you have to start compute_data_GUI "blind", then visualize_data_GUI switch to the new result.
2 . There is no possibility of displacement correction (this function is present, for example, in VEDDAC software). It allows to remove the object moving component from the displacement data and consider only deformation-related displacement. Of course this function does not affect the calculation of deformation, but you can't estimate the deformation-related displacement, which is negligibly small against sample shift.
3 . Code delete_data_GUI is not very convenient to use:
- can't undo the action: one mistake and you have to start over;
- There is only one tool removing items - a task corners of the rectangle ;
- can't zoom in ;
- The images are not visible behind a dense grid;
4 It would be great to count stress tensor in the end. The code should be easy: we just need a strain tensor, Young's modulus and Poisson coefficient
For users of Matlab 2013a and 2013b:
A change between Matlab 2012b, which was used to write this code, and 2013a/b causes the progress bar during the correlation of the images to not work properly when operating in parallel mode. To fix this issue, please download the latest version of the progress bar code from File Exchange number 35609 (http://www.mathworks.com/matlabcentral/fileexchange/35609) and replace the progress bar files included with the DIC codes with the new ones.