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FAQs

How can I turn on/off the D435i/D455 depth stream?

The D435i/D455 camera is a depth camera that SLAMcore software can use for SLAM. We are able to provide a depth output alongside our pose information.

On x64 Platforms

On x64 platforms the depth stream is turned on by default, and can be optionally turned off using the following command at startup:

# Turn depth OFF on SLAMcore Visualiser, Dataset Recorder, Dataset Recorder CLI or Dataset Processor
$ slamcore_* --no-depth

# Turn depth OFF on ROS1 Wrapper
$ roslaunch slamcore_slam run_slam.launch \                  # for run_slam.launch OR
  override_realsense_depth:=true \
  realsense_depth_override_value:=false

$ roslaunch slamcore_slam run_dataset_recorder.launch \      # for run_dataset_recorder.launch OR
  override_realsense_depth:=true \
  realsense_depth_override_value:=false

# Turn depth OFF on ROS2 Wrapper
$ ros2 launch slamcore_slam slam_publisher.launch.py \       # for slam_publisher.launch.py OR
  override_realsense_depth:=true \
  realsense_depth_override_value:=false

$ ros2 launch slamcore_slam run_dataset_recorder.launch.py \ # for run_dataset_recorder.launch.py
  override_realsense_depth:=true \
  realsense_depth_override_value:=false

On NVIDIA Platforms

Due to lower system bandwidth on NVIDIA platforms, the depth stream is turned off by default, and can be optionally turned on using the following command at startup:

# Turn depth ON on SLAMcore Visualiser, Dataset Recorder, Dataset Recorder CLI or Dataset Processor
$ slamcore_* --depth

# Turn depth ON on ROS1 Wrapper
$ roslaunch slamcore_slam run_slam.launch \                  # for run_slam.launch OR
  override_realsense_depth:=true \
  realsense_depth_override_value:=true

$ roslaunch slamcore_slam run_dataset_recorder.launch \      # for run_dataset_recorder.launch OR
  override_realsense_depth:=true \
  realsense_depth_override_value:=true

# Turn depth ON on ROS2 Wrapper
$ ros2 launch slamcore_slam slam_publisher.launch.py \       # for slam_publisher.launch.py OR
  override_realsense_depth:=true \
  realsense_depth_override_value:=true

$ ros2 launch slamcore_slam run_dataset_recorder.launch.py \ # for run_dataset_recorder.launch.py
  override_realsense_depth:=true \
  realsense_depth_override_value:=true

Streaming depth alongside pose can possibly lead to some of the following:

• Degradation of positioning performance in low light conditions due to a known issue with RealSense cameras (IR leak into grayscale frames)

• Issues with lower quality USB connectors

• Higher disk usage when saving datasets, whereby at 848x480 resolution:

	x64	NVIDIA Jetson Platforms
Default depth setting	ON	OFF
Disk usage with --no-depth	Up to 1.4 GB/minute	Up to 0.7 GB/minute
Disk usage with --depth	Up to 5.4 GB/minute	Up to 2.7 GB/minute

How can I change frame rate?

Note

The option to change the frame rate is currently only available on SLAMcore Tools - SLAMcore Visualiser, Dataset Recorder, Dataset Recorder CLI and Dataset Processor.

It is not available in the ROS and C++ APIs yet.

When using SLAMcore Tools, the frame rate can be overwritten with the --fps flag.

	x64	NVIDIA Jetson Platforms
Default frame rate	30 fps	15 fps

RealSense Cameras

Please note that both the --fps flag and --depth/--no-depth flag affect the framerate of SLAM. With --depth the effective framerate for both depth and IR is halved.

Datasets are recorded at the full framerate for IR and Depth.

–fps	–depth	IR FPS (SLAM)	Depth FPS (SLAM)	IR FPS (Recording)	Depth FPS (Recording)
15	0	15	0	15	0
15	1	7.5	7.5	15	15
30	0	30	0	30	0
30	1	15	15	30	30
60	0	60	0	60	0
60	1	30	30	60	60

MyntEye2 Cameras

The following framerates are supported on the MyntEye2. SLAM and dataset recording are both at the nominal framerate.

–fps
10
15
20
25
30
35
40
45
50
55

What are the /slamcore parameters for?

Some read-only properties are exposed as parameters in the ROS Parameters Server within the /slamcore namespace. They are reserved for future use.

What should I do if my test results are poor?

Try a more suitable configuration for your use case, see SLAM Configuration for more information.

Does your software work in low light conditions?

The IR illumination module on the RealSense D435i camera is not compatible with our visual features, so we do not use it as an illumination source. The module is purely for depth information used in features such as 2.5D height mapping (see Height Mapping Mode for more information).

As such, our visual features rely on the stereo imagers and are designed to be robust to illumination changes, although it does depend on the light levels in the night time environment. Note that with lower light levels the exposure time typically increases which is more likely to lead to motion blur, which can have a detrimental effect on our algorithms.

Can I run the SLAMcore software without internet connection?

An internet connection is required at the start of each session to access the SLAMcore software license and for telemetry collection. This requirement can be discussed as part of a negotiation for commercial deployment.

Can you recommend a suitable x64 laptop?

Any recent mid-range laptop (Core i5, i7) with AVX2 should work. If you plan to run ROS1 rviz on the machine you may need higher specifications. A popular alternative to laptops are Intel NUCs.