mirror of
https://github.com/opencv/opencv.git
synced 2024-12-16 10:29:11 +08:00
76 lines
2.3 KiB
Markdown
76 lines
2.3 KiB
Markdown
|
Point cloud visualisation {#tutorial_point_cloud}
|
||
|
==============================
|
||
|
|
||
|
| | |
|
||
|
| -: | :- |
|
||
|
| Original author | Dmitrii Klepikov |
|
||
|
| Compatibility | OpenCV >= 5.0 |
|
||
|
|
||
|
Goal
|
||
|
----
|
||
|
|
||
|
In this tutorial you will:
|
||
|
|
||
|
- Load and save point cloud data
|
||
|
- Visualise your data
|
||
|
|
||
|
Requirements
|
||
|
------------
|
||
|
|
||
|
For visualisations you need to compile OpenCV library with OpenGL support.
|
||
|
For this you should set WITH_OPENGL flag ON in CMake while building OpenCV from source.
|
||
|
|
||
|
Practice
|
||
|
-------
|
||
|
|
||
|
Loading and saving of point cloud can be done using `cv::loadPointCloud` and `cv::savePointCloud` accordingly.
|
||
|
|
||
|
Currently supported formats are:
|
||
|
- [.OBJ](https://en.wikipedia.org/wiki/Wavefront_.obj_file) (supported keys are v(which is responsible for point position), vn(normal coordinates) and f(faces of a mesh), other keys are ignored)
|
||
|
- [.PLY](https://en.wikipedia.org/wiki/PLY_(file_format)) (all encoding types(ascii and byte) are supported with limitation to only float type for data)
|
||
|
|
||
|
@code{.py}
|
||
|
vertices, normals = cv2.loadPointCloud("teapot.obj")
|
||
|
@endcode
|
||
|
|
||
|
Function `cv::loadPointCloud` returns vector of points of float (`cv::Point3f`) and vector of their normals(if specified in source file).
|
||
|
To visualize it you can use functions from viz3d module and it is needed to reinterpret data into another format
|
||
|
|
||
|
@code{.py}
|
||
|
vertices = np.squeeze(vertices, axis=1)
|
||
|
|
||
|
color = [1.0, 1.0, 0.0]
|
||
|
colors = np.tile(color, (vertices.shape[0], 1))
|
||
|
obj_pts = np.concatenate((vertices, colors), axis=1).astype(np.float32)
|
||
|
|
||
|
cv2.viz3d.showPoints("Window", "Points", obj_pts)
|
||
|
|
||
|
cv2.waitKey(0)
|
||
|
@endcode
|
||
|
|
||
|
In presented code sample we add a colour attribute to every point
|
||
|
Result will be:
|
||
|
|
||
|
![](tutorial_point_cloud_teapot.jpg)
|
||
|
|
||
|
For additional info grid can be added
|
||
|
|
||
|
@code{.py}
|
||
|
vertices, normals = cv2.loadPointCloud("teapot.obj")
|
||
|
@endcode
|
||
|
|
||
|
![](teapot_grid.jpg)
|
||
|
|
||
|
Other possible way to draw 3d objects can be a mesh.
|
||
|
For that we use special functions to load mesh data and display it.
|
||
|
Here for now only .OBJ files are supported and they should be triangulated before processing (triangulation - process of breaking faces into triangles).
|
||
|
|
||
|
@code{.py}
|
||
|
vertices, _, indices = cv2.loadMesh("../data/teapot.obj")
|
||
|
vertices = np.squeeze(vertices, axis=1)
|
||
|
|
||
|
cv2.viz3d.showMesh("window", "mesh", vertices, indices)
|
||
|
@endcode
|
||
|
|
||
|
![](teapot_mesh.jpg)
|