Update README.md

Co-authored-by: Liu Wenxin <[email protected]>

README.md

@@ -58,7 +58,7 @@ Timestamps (t) are in microseconds (us). Each row corresponds to data in a singl
 - `my_timestamps_p.txt` VIO timestamps.
   - [t]
   - Note: single column, skipped first 20 frames
-- `imu_measurements.txt` IMU data, raw and calibrated using VIO calibration
+- `imu_measurements.txt` raw and calibrated IMU data
   - [t, acc_raw (3), acc_cal (3), gyr_raw (3), gyr_cal (3), has_vio] 
   - Note: has been interpolated evenly between images. Every timestamp in my_timestamps_p.txt will have a corresponding timestamp in this file (has_vio==1)
 - `evolving_state.txt` VIO evolving states at IMU rate.