kablir gives an irregular result for calibrating RGB and IMU of D455 #2568
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Hi @Hypothesis-Z I would recommend using official RealSense calibration tools to calibrate RGB and the IMU module. Non-official tools are not designed specially for RealSense cameras and cannot save the calibration to the camera hardware. RGB can be calibrated using the official Dynamic Calibration tool. Instructions for installing on Ubuntu can be found on page 14 onwards of the user guide for the tool. The IMU can be calibrated with a Python tool. https://github.com/IntelRealSense/librealsense/tree/master/tools/rs-imu-calibration https://dev.intelrealsense.com/docs/imu-calibration-tool-for-intel-realsense-depth-camera In regard to lost frames, tracking may be lost if the camera moves quickly or makes a sharp turn. This is described in Intel's D435i SLAM guide. https://github.com/IntelRealSense/realsense-ros/wiki/SLAM-with-D435i The built-in IMU can only keep track for a very short time. Moving or turning too quickly will break the sequence of successful point cloud matches and will result in the system losing track. It could happen that the system will recover immediately if stopped moving but if not, the longer the time passed since the break, the farther away it will drift from the correct position. The odds for recovery get very slim, very quickly. The parameters set in the launch file are most likely not ideal but this is a good starting point for calibrating. In regard to IMU time offset, you could try disabling the global time setting by including global_time_enabled:=false in your launch instruction to see whether it improves the results. |
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@MartyG-RealSense Thank you for quick response. I will try the calibraion tools and settings |
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@Hypothesis-Z Thanks very much for the update. I look forward to hearing about your test results from the calibraion tools and the setting |
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Hi @Hypothesis-Z Do you require further assistance with this case, please? Thanks! |
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@MartyG-RealSense Yes, thank you. I did IMU calibration with official tools recently. According to the last section of documentation, the script wrote the prameters into the camera. Does it mean that the data of |
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A key benefit of IMU calibration is that it optimizes the accuracy of the gravity acceleration values. So it is /camera/accel/sample that it is likely to have the most effect on. |
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Hi @Hypothesis-Z Do you have an update about this case that you can provide, please? Thanks! |
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Hi @Hypothesis-Z Do you require further assistance with this case, please? Thanks! |
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Hi! @MartyG-RealSense I am confused with |
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If global_time_enabled is set to True then the SDK will attempt to use a common timestamp for all cameras and does this by comparing camera hardware time with the computer's clock time, as described at IntelRealSense/librealsense#3909 In the RealSense ROS wrapper though, enabling global time has a less significant effect than it does in the librealsense SDK because ROS already corrects for timestamp drift anyway. It is possible to synchronize devices as 'slaves' to a 'master' trigger so that the slave cameras attempt to follow the master's timestamp timing by using the inter_cam_sync_mode hardware sync system. https://dev.intelrealsense.com/docs/multiple-depth-cameras-configuration |
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Hi @Hypothesis-Z Do you require further assistance with this case, please? Thanks! |
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Case closed due to no further comments received. |
I tried to calibrate RGB and IMU of RealSense D455 using kablir but failed.
Here is kalibr output:
They should not have a 41cm offset on z-axis. Becides, time offset is also very large though I have set
enable_sync. I wonder what could I do to acquire a good calibration result.Another problem is IMU lost frames for a long time (sometimes for 1 second), why?
Looking forward a response...
Thanks.
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