A benchmark for the evaluation of RGB-D SLAM systems (ATE/RPE) [论文阅读]
# 2012-A benchmark for the evaluation of RGB-D SLAM systems
视觉SLAM:算法精度评价指标(ATE、RPE)
**数据集格式**
All data was recorded at full resolution (640×480) and full frame rate (30 Hz) of the Microsoft Xbox Kinect sensor.
- “rgb/”: a folder containing all color images (PNG for- mat, 3 channels, 8 bit per channel),
- “depth/”: same for the depth images (PNG format, 1 channel, 16 bit per channel, distance in meters scaled by factor 5000),
- “rgb.txt”: a text file with a consecutive list of all color images (format: timestamp filename),
- “depth.txt”: same for the depth images (format: times- tamp filename),
- “imu.txt”: a text file containing the timestamped ac- celerometer data (format: timestamp fx fy fz),
- “groundtruth.txt”: a text file containing the ground truth trajectory stored as a timestamped translation vector and unit quaternion (format: timestamp tx ty tz qx qy qz qw).
**EVALUATION METRICS**
The estimated trajectory: $P_1,...,P_n \in SE(3)$
The ground truth trajectory: $Q_1,...,Q_n \in SE(3)$
A fixed time interval $\Delta$
**RPE: relative pose error 相对位姿误差**
We define the relative pose error at time step i as
$E_i:=(Q^{-1}Q_{i+\Delta})^{-1}(P_i^{-1}P_{i+\Delta})$
From a sequence of n camera poses, we obtain in this way m = n − ∆ individual relative pose errors along the sequence. From these errors, we propose to compute the root mean squared error (RMSE) over all time indicies of the translational component as:
$RMSE(E_{1:n},\Delta):=(\frac1m \sum_{i=1}^m || trans(E_i)||^2)^{\frac12}$
For the evaluation of SLAM systems, it therefore makes sense to average over all possible time intervals $\Delta$:
$RMSE(E_{1:n}):=\frac1n\sum_{\Delta=1}^n \text{RMSE}(E_{1:n},\Delta)$
**ATE: absolute trajectory error 绝对轨迹误差**
The global consistency can be evaluated by comparing the absolute distances between the estimated and the ground truth trajectory.
S corresponding to the least-squares solution that maps the estimated trajectory P1:n onto the ground truth trajectory Q1:n. Given this transformation, the absolute trajectory error at time step i can be computed as:
$F_i:=Q_i^{-1}SP_i$
where $S\in Sim(3)$
we propose to evaluate the root mean squared error over all time indices of the translational components, i.e.,
$RMSE(F_{1:n},\Delta):=(\frac1n \sum_{i=1}^n || trans(F_i) || ^2)^{\frac12}$
The RPE can be used to evaluate the global error of a trajectory by averaging over all possible time intervals. Note that the RPE considers both translational and rotational errors, while the ATE only considers the translational errors.
RPE 既考虑旋转又考虑位移误差,而ATE只考虑位移误差
# EVO TOOLS
This package provides executables and a small library for handling, evaluating and comparing the trajectory output of odometry and SLAM algorithms.
Supported trajectory formats:
- 'TUM' trajectory files
- 'KITTI' pose files
- 'EuRoC MAV' (.csv groundtruth and TUM trajectory file)
- ROS bagfile with geometry_msgs/PoseStamped, geometry_msgs/TransformStamped, geometry_msgs/PoseWithCovarianceStamped or nav_msgs/Odometry topics or TF messages
Github: https://github.com/MichaelGrupp/evo
![Error mapped onto trajectory](https://raw.githubusercontent.com/MichaelGrupp/evo/master/doc/assets/ape_demo_ORB_map.png)
Installation:
```sh
pip install evo --upgrade --no-binary evo
```
# References
- Sturm, J., Engelhard, N., Endres, F., Burgard, W., & Cremers, D. (2012). A benchmark for the evaluation of RGB-D SLAM systems. IEEE International Conference on Intelligent Robots and Systems, 573–580. https://doi.org/10.1109/IROS.2012.6385773
- [RGB-D SLAM Dataset and Benchmar](https://vision.in.tum.de/data/datasets/rgbd-dataset)
- [MichaelGrupp/evo](https://github.com/MichaelGrupp/evo)
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