Update README

ke-sun · ke-sun · commit 37dd131d3394 · 2018-01-08T14:33:13.000-05:00
diff --git a/README.md b/README.md
@@ -5,7 +5,7 @@ The `MSCKF_VIO` package is a stereo version of MSCKF. The software takes in sync
 
 The software is tested on Ubuntu 16.04 with ROS Kinetic.
 
-Video: [https://www.youtube.com/watch?v=OXSB8Bze0cY](https://www.youtube.com/watch?v=OXSB8Bze0cY)  
+Video: [https://www.youtube.com/watch?v=OXSB8Bze0cY](https://www.youtube.com/watch?v=OXSB8Bze0cY)
 Paper Draft: [https://arxiv.org/abs/1712.00036](https://arxiv.org/abs/1712.00036)
 
 ## License
@@ -21,7 +21,7 @@ sudo apt-get install libsuitesparse-dev
 ```
 
 ## Compling
-The software is a standard catkin package. Make sure the package is on `ROS_PACKAGE_PATH` after cloning the package to your workspace. And the normal procedure for compling a catkin package will work.
+The software is a standard catkin package. Make sure the package is on `ROS_PACKAGE_PATH` after cloning the package to your workspace. And the normal procedure for compiling a catkin package should work.
 
 ```
 cd your_work_space
@@ -30,7 +30,9 @@ catkin_make --pkg msckf_vio --cmake-args -DCMAKE_BUILD_TYPE=Release
 
 ## Calibration
 
-An accurate calibration is crucial for successfully running the software. To get the best performance of the software, the stereo cameras and IMU should be hardware synchronized. [Kalibr](https://github.com/ethz-asl/kalibr) can be used to calibrate the transformantion between the stereo cameras and IMU. The yaml file generated by Kalibr can be directly used in this software with slight modifications. See `example_calib.yaml` in the `config` folder for the modifications.
+An accurate calibration is crucial for successfully running the software. To get the best performance of the software, the stereo cameras and IMU should be hardware synchronized. [Kalibr](https://github.com/ethz-asl/kalibr) can be used to calibrate the transformantion between the stereo cameras and IMU. The yaml file generated by Kalibr can be directly used in this software with slight modifications. See calibration files in the `config` folder for details. The two calibration files in the `config` folder should work directly with the EuRoC and [fast flight](https://github.com/KumarRobotics/msckf_vio/wiki) datasets.
+
+The filter requires 200 IMU messages to initialize gyro bias, acc bias, and initial orientation. Therefore, the robot is required to start from static in order to initialize the VIO successfully.
 
 ## Example Usage
 
@@ -46,7 +48,7 @@ There are launch files prepared for the EuRoC and fast flight dataset separately
 
 IMU messages is used for compensating rotation in feature tracking, and 2-point RANSAC.
 
-`camx_image` (`sensor_msgs/Image`)
+`cam[x]_image` (`sensor_msgs/Image`)
 
 Synchronized stereo images.
 
@@ -84,4 +86,4 @@ Odometry of the IMU frame including a proper covariance.
 
 `feature_point_cloud` (`sensor_msgs/PointCloud2`)
 
-Shows current features in the map which may be used for estimation.
+Shows current features in the map which is used for estimation.
