dicengine
Questions for better scientific accuracy
Dear DICe Development Team, I am a PhD researcher working on experimental rock mechanics, and I am currently using DICe to analyze strain and displacement from rock sample images. The software is very powerful and helpful for my research, and I appreciate all the work you’ve put into developing it.
However, I have a few questions that I hope you can clarify for better scientific accuracy and reporting:
- Camera Calibration:
How do I properly calibrate the camera distance and lens specifications (in mm) for accurate displacement/strain measurements?
Is there a recommended procedure or guideline for setting the correct lens focal length and camera-to-sample distance?
- Graph Export:
How can I export the generated strain/displacement graphs to Excel or CSV? I would like to use the raw data for further statistical and comparative analysis in my research.
- Units of Measurement:
Many results (e.g., strain, displacement) appear as numbers without specified units. Could you please confirm:
What are the default units for strain (e.g., % or unitless)?
What are the displacement units (pixels or real-world mm)?
- Graph Interpretation / Formula Documentation:
Is there a manual or documentation that explains:
How each type of graph is calculated?
The formulae and methods used to derive strain/displacement fields?
Any corresponding unit conversions if needed?
Having this information will help ensure that I correctly interpret the results in a scientifically valid way.
Hi,
For 1, if you are doing 2d analysis, you can do a single camera calibration by clicking the "perform cal" button. This usesthe OpenCV camera calibration routines (more info here https://learnopencv.com/camera-calibration-using-opencv/).
The raw data is contained in the output files in the results folder. If you have live plot points selected, you can use the live plot files to get the data. Some of the information might be in the .dice folder that gets created in your workspace folder
If you are running an uncalibrated analysis, the units are always in pixels. If you calibrate the results, additional fields like "MODEL_DISPLACEMENTS_X", etc. will get created which are in whatever physical units you used for the calibration.
All of the docs on how the strain is calculated, etc. are in this folder: https://github.com/dicengine/dice/tree/master/doc/reports
Thanks
Thank you so much sir for the clarification
On Wed, 7 May 2025, 7:48 pm Digital Image Correlation Engine (DICe), < @.***> wrote:
dicengine left a comment (dicengine/dice#343) https://github.com/dicengine/dice/issues/343#issuecomment-2858776228
Hi,
For 1, if you are doing 2d analysis, you can do a single camera calibration by clicking the "perform cal" button. This usesthe OpenCV camera calibration routines (more info here https://learnopencv.com/camera-calibration-using-opencv/).
The raw data is contained in the output files in the results folder. If you have live plot points selected, you can use the live plot files to get the data. Some of the information might be in the .dice folder that gets created in your workspace folder
If you are running an uncalibrated analysis, the units are always in pixels. If you calibrate the results, additional fields like "MODEL_DISPLACEMENTS_X", etc. will get created which are in whatever physical units you used for the calibration.
All of the docs on how the strain is calculated, etc. are in this folder: https://github.com/dicengine/dice/tree/master/doc/reports
Thanks
— Reply to this email directly, view it on GitHub https://github.com/dicengine/dice/issues/343#issuecomment-2858776228, or unsubscribe https://github.com/notifications/unsubscribe-auth/BFHV5JEUWEAARFJ6RYQVMVL25II5HAVCNFSM6AAAAAB4T5LR6OVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDQNJYG43TMMRSHA . You are receiving this because you authored the thread.Message ID: @.***>
Dear DICe Development Team,
Thank you for your earlier support. I have a follow-up question regarding post-processing:
After importing DICe results into ParaView, I would like to know how to extract and export the data, specifically:
Strain and Displacement Data:
How can I extract the full-field strain or displacement values from the DICe output in ParaView?
Is there a way to export these results as a CSV or similar file for further analysis (e.g., for plotting in external tools)?
Line Graphs or Profile Extraction:
How can I generate and export a line plot?
If you could provide any guidelines, steps, or documentation links for this kind of data handling in ParaView, it would greatly support my efforts in accurately reporting and analyzing the experimental results. Actually, I have seen your YouTube video for that, but after starting the Paraview software, it is missing some important data,a like how to see the strain graph along with the image, so that it will be helpful in scientific writing
Thank you again for your excellent software and support.
Sincerely, Sourav Das PhD Researcher Cotton University, Assam