Structrock

A cross-platform outcrop point cloud processing system.

Structrock is released under the terms of the BSD license, and thus free for commercial and research use. Feel free to analyze your own outcrop point cloud data, to add Structrock into your own project. You are welcomed to make contributions to this project. Email [email protected], or open an issue here on GitHub for support.

Citation (more to be added soon):

@article{Wang17,
	title={A region-growing approach for automatic outcrop fracture extraction from a three-dimensional point cloud},
	author={Wang, Xin and Zou, Lejun and Shen, Xiaohua and Ren, Yupeng and Qin, Yi},
	journal={Computers \& Geosciences},
	volume={99},
	pages={100-106},
	year={2017},
	doi={10.1016/j.cageo.2016.11.002},
	publisher={Elsevier},
}
@article{Wang_arxiv2017,
	title={Outcrop fracture characterization on suppositional planes cutting through digital outcrop models (DOMs)},
	author={Wang, Xin and Zou, Lejun and Ren, Yupeng and Qin, Yi and Guo, Zhonghao and Shen, Xiaohua},
	journal={arXiv preprint arXiv:1707.03437},
	year={2017}
}
@article{Wang2019122,
	title = {Historical shear deformation of rock fractures derived from digital outcrop models and its implications on the development of fracture systems},
	author = {Xin Wang and Yi Qin and Zhaohui Yin and Lejun Zou and Xiaohua Shen},
	journal = {International Journal of Rock Mechanics and Mining Sciences},
	volume = {114},
	pages = {122 - 130},
	year = {2019},
	issn = {1365-1609},
	doi = {https://doi.org/10.1016/j.ijrmms.2018.12.018},
	url = {http://www.sciencedirect.com/science/article/pii/S1365160918307652"}
}
@article{Wang2020,
author = {Wang, Xin and Gao, Feng},
title = {Quantitatively Deciphering Paleostrain From Digital Outcrops Model and its Application in the Eastern Tian Shan, China},
journal = {Tectonics},
volume = {39},
number = {7},
pages = {e2019TC005999},
keywords = {clustering analysis, digital outcrops model, eastern Tian Shan, paleostrain, quantitative methods, strain tensor},
doi = {10.1029/2019TC005999},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019TC005999},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2019TC005999},
note = {e2019TC005999 10.1029/2019TC005999},
year = {2020}
}

Detailed results obtained from a portion of the point cloud. (a) A portion of the outcrop and (b) its point cloud. (c) Segmentation results obtained using the proposed algorithm. Different fracture regions are shown in various colors, and the non-fracture regions are shown in red. (d) Estimated fracture planes obtained from the segmentation results.

(a) The outcrop used to test the proposed algorithm and (b) the segmentation results. Different fracture regions are shown by different colors, and the non-fracture regions are shown in red.

Dependencies

Point Cloud Library (PCL)

PCL is a standalone, large scale, open project for 2D/3D image and point cloud processing. Official website: http://pointclouds.org/. Github repository: https://github.com/PointCloudLibrary/pcl.

Version required: 1.6, still having compatibility problems with versions > 1.6.

Qt

Qt is a cross-platform C++ application development framework. Official website: http://www.qt.io/.

Version required: >= 4.8.

PostgreSQL

PostgreSQL often simply Postgres, is an object-relational database management system (ORDBMS) with an emphasis on extensibility and standards-compliance. It is used to support an experimental function of structrock: accessing very large LiDAR datasets stored in PostgreSQL databases.

Functions

Structrock provide a platform on which workflows of processing outcrop point clouds can be designed. A region-growing algorithm for automatic outcrop fracture extraction from a three-dimensional point cloud is implemented.

Structrock can run in both GUI and command-line modes. In GUI mode, users interact with Structrock to perform certain processing action and provide processing parameters through input dialogs. In command-line mode, Structrock receive the path to a text file (we call it the workflow file) that contains processing actions and parameters. Lines of actions are separated by ";" and parameters are separated by ",". It will do these processing actions one by one until the end or errors occur.

An example of workflow file:

openpcd,E:\Downloads\parameters_test\0134067-Data-ready.pcd,mute;
knnormal,30,mute;
rgsegmentation,9,0.06,20,4,30,false,mute;
saveclusters,E:\Downloads\parameters_test\Clusters\Data_9_20.bin,mute;
quitsession;

Build from source

First, all dependencies, PCL(1.6), Qt, boost, Eigen, FLANN, VTK, QHull and OpenNI should be installed properly.

Download and install CMake, Official website: https://cmake.org/.

Make a new folder named "build" beside the folder containing source files (call it, say, "src").

On Windows

Make sure Visual Studio 2010 is properly installed. Open CMake, set "Where is the source code" to the path to "src" and set "Where to build the binary" to the path to "build". Click "Configure", and select Visual Studio 10 2010, if no errors occur, click "Generate". Open generated "structrock.sln" file, set "structrock" as the "StartUp Project", add "/ENTRY:mainCRTStartup" to "structrock"'s "Linker->Command Line" properties, start compilation.

On Linux

Open terminal window, go to "build" folder, run "cmake ../src", then run "make".

After a successful compilation, Structrock looks like this:

Processing actions

downsample

Description: Downsample the point cloud given the minimum point distance (meter).

Parameters:

1. "Minimum point distance" (required, double),

2. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

3. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

ftriangulation

Description: Fast triangulation of fracture faces extracted from the outcrop point cloud.

Parameters:

1. "Number of neoghbor points for local normal estimation" (required, int),

2. "SearchRadius: the maximum edge length for every triangle" (required, double),

3. "Mu: the maximum acceptable distance for a point to be considered, relative to the distance of the nearest point (in order to adjust to changing densities)" (required, double),

4. "MaximumNearestNeighbors: defines how many neighbors are searched for" (required, int),

5. "MaximumSurfaceAgle: points are not connected to the current point if their normals deviate more than the specified angle" (required, double),

6. "MinimumAngle: the minimum angle in each triangle" (required, double),

7. "MaximumAngle: the maximum angle in each triangle" (required, double),

8. "NormalConsistency: if guarantee normal consistency" (required, bool),

9. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

10. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

knnormal

Description: Find k nearest neighbors given k, and calculate the normal of the neighbors.

Parameters:

1. "Number of neoghbor points" (required, int),

2. showcurvature (optional, follow required parameters, but before "mute" and "nolog", if declared, the curvature map on the point cloud will be displayed on the screen),

3. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

4. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

multistation

Description: Registration of multistation data.

Parameters:

1. "The list of file names of the multistation data, separated by '|'" (required),

2. "Minimum point distance for downsampling before the alignment" (required, double),

3. "Standard deviation for statistically removing the outliers before the alignment" (required, double),

4. "Number of neoghbor points for local normal estimation before the alignment" (required, int),

5. "MaxCorrespondenceDistance: the maximum distance between two correspondences (src<->tgt)" (required, double),

6. "EuclideanFitnessEpsilon: the maximum allowed distance error before the algorithm will be considered to have converged" (required, double),

7. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

8. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

openclusters

Description: Read data of fracture faces extracted from the outcrop point cloud.

Parameters:

1. "The path and file name of the clusters file" (required),

2. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

3. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

openftriangulation

Description: Read data of the triangulated fracture faces.

Parameters:

1. "The path and file name of the triangulated fracture faces" (required),

2. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

3. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

openpcd

Description: Open a .pcd file.

Parameters:

1. "The path and file name of the file to open" (required),

2. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

3. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

openxyz

Description: Open a .txt file that contains 3 columns: x, y, z.

Parameters:

1. "The path and file name of the file to open" (required),

2. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

3. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

quitsession

Description: Quit Structrock.

Parameters:

No parameters.

ranormal

Description: Find the neighbors given the search radius, and calculate the normal of the neighbors.

Parameters:

1. "Search radius" (required, double),

2. showcurvature (optional, follow required parameters, but before "mute" and "nolog", if declared, the curvature map on the point cloud will be displayed on the screen),

3. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

4. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

readnshowshearfeatures

Description: Read and show shear features.

Parameters:

1. "Type of features to show" (required, "striations" or "steps"),

2. "The path and file name of the shear features data" (required),

3. "Threshold under which the fracture will be considered unsheared, and the feature will not show" (optional, should be provided in the form like "threshold:0.04"),

4. "Percent of extreme values out of the color bar" (optional, should be provided in the form like "percent:0.08"),

5. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

6. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

resample

Description: Resample the point cloud given the search radius (meter).

Parameters:

1. "Search radius" (required, double),

2. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

3. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

rgsegmentation

Description: Perform the Region Growing Segmentation given the parameters.

Parameters:

1. "Local surface normal deviation threshold" (required, double, degree),

2. "Curvature threshold" (required, double, only used when the smooth mode is on),

3. "Transmission error threshold" (required, double, degree, only used when the smooth mode is off),

4. "Minimum number of point a segmented patch must have to be recorded" (required, int),

5. "The number of neighbors will participate in the region growing" (required, int),

6. "Is it on smooth mode?" (required, boolean),

7. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

8. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

rostatic

Description: Statistically remove the outliers of the point cloud given the standard deviation.

Parameters:

1. "Standard deviation" (required, double),

2. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

3. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

saveclusters

Description: Perform post-outcrop-fracture-extraction actions and save the results into .bin and txt files.

Parameters:

1. "The path and file name of the file to save" (required),

2. mute (optional, follow required parameters, if declared, the result of this action will not be displayed on the screen),

3. nolog (optional, follow required parameters, if declared, this action and the time it takes to perform this action will not be logged)

saveftriangulation

Description: Save the triangulated fracture faces.

Parameters:

1. "The path and file name of the data to save" (required)

savenormals

Description: Save current normals to .pcd file.

Parameters:

1. "The path and file name of the file to save" (required)

savepcdascii

Description: Save current data to .pcd file with ASCII encoding.

Parameters:

1. "The path and file name of the file to save" (required),

2. rgb (optional, follow required parameters, if declared, will save with rgb color)

savepcdbinary

Description: Save current data to .pcd file with binary encoding.

Parameters:

1. "The path and file name of the file to save" (required),

2. rgb (optional, follow required parameters, if declared, will save with rgb color)

shearpara

Description: Calculating the shear strength parameter.

Parameters:

1. "The path and file name to save the shear strength parameters" (required),

2. savescreen (optional, follow required parameters, if declared, will save a screenshot of fracture faces corresponding to its shear strength parameter)

showsfeature

Description: Show different kinds of features on the fracture faces or on the outcrop. Features include the fracture faces' roughness, area, linear features, circular features, wave-like features, and etc.

Parameters:

1. "The name of the feature" (required, currently "roughness" and "area" are included.)

2. "Percentage Out threshold" (Optional; Less than 0.5 and bigger than 0.0. If provided, drop the head and the tail in the distribution of the feature to show the variation of the majority of the feature data.)

showstereonet

Description: Show and save (as PDF) the stereonet plot of the fracture data.

Parameters:

1. "The path and file name of the file to save" (required)