Dense 3D Reconstruction from Stereo
This is a ROS package for real-time 3D reconstruction from stereo images. Currently this version uses LIBELAS for generating dense disparity maps as a baseline. The method for generation of disparity maps can be changed based on user preferences.
This package serves as a visualization tool for dense disparity maps and point clouds. Additionally, a tool for transforming point clouds to a different reference frame is also included.
Usually, the point clouds are formed in the reference frame of the left camera. For ground robots, often the point clouds need to be transformed to a different frame e.g., a reference frame with the origin at the centre of rotation of the robot projected on to the ground plane. These transformations are hard to calculate mathematically - this tool can be used to find the transformations visually.
- Author: Sourish Ghosh
Dependencies
Stereo Calibration
A calibrated pair of cameras is required for stereo rectification and calibration files should be stored in a .yml
file.
This repository contains all the tools and instructions to calibrate stereo cameras.
The rotation and translation matrices for the point cloud transformation should be named as XR
and XT
in the calibration file. XR
should be a 3 x 3
matrix and XT
should be a 3 x 1 matrix. Please see a sample calibration file in the calibration/
folder.
Compiling
Clone the repository:
$ git clone https://github.com/umass-amrl/stereo_dense_reconstruction
For compiling the ROS package, rosbuild
is used. Add the path of the ROS package to ROS_PACKAGE_PATH
and put the following line in your .bashrc
file.
Replace PATH
by the actual path where you have cloned the repository:
$ export ROS_PACKAGE_PATH=$ROS_PACKAGE_PATH:/PATH
Execute the build.sh
script:
$ cd stereo_dense_reconstruction
$ chmod +x build.sh
$ ./build.sh
Running Dense 3D Reconstruction
$ ./bin/dense_reconstruction [OPTION...]
Usage: dense_reconstruction [OPTION...]
-l, --left_topic=STR Left image topic name
-r, --right_topic=STR Right image topic name
-c, --calib_file=STR Stereo calibration file name
-w, --calib_width=NUM Calibration image width
-h, --calib_height=NUM Calibration image height
-u, --out_width=NUM Rectified image width
-v, --out_height=NUM Rectified image height
-d, --debug=NUM Set d=1 for cam to robot frame calibration
This node outputs the dense disparity map as a grayscale image on the topic /camera/left/disparity_map
and the corresponding point cloud on the topic
/camera/left/point_cloud
.
A sample dataset can be found here.
Point Cloud Transformation
The point cloud can be viewed on rviz
by running:
$ rosrun rviz rviz
To transform the point cloud to a different reference frame, the XR
and XT
matrices (rotation and translation) in the calibration file need to be changed.
This can be done real-time by the running:
$ rosrun rqt_reconfigure rqt_reconfigure
If you change the Euler Angles in rqt_reconfigure
you should be able to see the point cloud transform. Don't forget to set d=1
when running the
dense_reconstruction
node. This prints out the new transformation matrices as you transform the point cloud.
License
This software is released under the GNU GPL v3 license.