Visualize¶

Ouster’s OpenGL-based visualizer allows for easy visualization from pcaps and sensors on all platforms the Ouster SDK supports.

Using ouster-cli is a fastest way to visualize data from a connected sensor, recorded pcap or OSF files with SLAM poses:

If you’ve installed the ouster-sdk (see Python Installation) then you’re all set to visualize with below command.

The following replays lidar data saved in a pcap file and visualizes the output. It will look for a metadata json file with the same name as the PCAP file by default, but you can specify the metadata explicitly. Set SAMPLE_DATA_PCAP_PATH (and optionally SAMPLE_DATA_JSON_PATH using -m if your metadata is stored separately) before running:

ouster-cli source --meta {SAMPLE_DATA_JSON_PATH} {SAMPLE_DATA_PCAP_PATH} viz

Using an Ouster Sensor¶

The following visualizes lidar data arriving on a udp port.

Note

Connecting to an Ouster sensor is covered in the Networking Guide section of the Ouster Sensor Documentation.

Set SENSOR_HOSTNAME to your sensor’s hostname or IP before running:

ouster-cli source {SENSOR_HOSTNAME} viz

Note

To make sure everything is connected, open a separate console window and try pinging the sensor. You should see some output like:

Linux/macOS

$ ping -c1 <SENSOR_HOSTNAME>
PING <SENSOR_HOSTNAME> (192.0.2.42) 56(84) bytes of data.
64 bytes from <SENSOR_HOSTNAME> (192.0.2.42): icmp_seq=1 ttl=64 time=0.217 ms

Windows x64

PS > ping /n 10 <SENSOR_HOSTNAME>
Pinging <SENSOR_HOSTNAME> (192.0.2.42) with 32 bytes of data:
Reply from 192.0.2.42: bytes=32 time=101ms TTL=124

Note that you may have to use ouster-cli source $SENSOR_HOSTNAME config first to configure your sensor properly.

You should get a view similar to:

../_images/ouster-viz.png — Ouster SDK CLI `ouster-cli source <sensor | pcap | osf> viz` visualization of OS1 128 sample data¶

You can control your visualizer with mouse and keyboard.

Click and drag rotates the view.
Middle click and drag moves the view.
Scroll adjusts how far away the camera is from the vehicle.

The default Ouster SDK CLI ouster-cli source <sensor | pcap | osf> viz visualizer view includes two 2D range images atop which can be cycled through the available fields, and a 3D point cloud on the bottom. For dual returns sensors, both returns are displayed by default.

Visualizer options¶

To get a list of all the options supported by the ouster-cli source … viz command, run:

ouster-cli source {SAMPLE_DATA_PCAP_PATH} viz --help

Keyboard controls¶

Press ? while the visualizer window is focused to print the current key bindings. The table below summarizes the defaults:

Camera

Playback

Key	What it does
`space`	Toggle pause
`. / ,`	Step one frame forward/back
`ctrl + . / ,`	Step 10 frames forward/back
`> / <`	Increase/decrease playback rate (during replay)
`h / shift+h`	Increase/decrease subframes (during replay)

2D View

Key	What it does
`b / B`	Cycle top 2D image
`n / N`	Cycle bottom 2D image
`i / shift+i`	Increase/decrease size of displayed 2D images
`ctrl+i`	Flip or hide 2D images

3D View

Other

Key	What it does
`o`	Toggle on-screen display
`?`	Print keys to standard out
`shift+z`	Save a screenshot of the current view
`shift+x`	Toggle a continuous saving of screenshots
`ctrl+x`	Toggle continuous screenshot format
`v / shift+v`	Cycle screenshot resolution factor
`esc`	Exit

Extrinsics¶

The visualizer includes an option to control the orientation of the point cloud in space when loaded. If you possess, say, an OS-DOME mounted upside down, you can start the visualizer with the option --extrinsics:

ouster-cli source --extrinsics "-1 0 0 0 0 1 0 0 0 0 -1 0 0 0 0 1" {SENSOR_HOSTNAME} viz

The input is a row-major homogeneous matrix.

Note

All basic primitives that you see as part of ouster-cli visualizer are exposed through viz.PointViz bindings. Please see the API reference for viz.PointViz for how to use it programmatically in Python.

Subframes¶

When replaying recorded data, pass --subframes to interpolate the camera pose between frames and visualize smoother motion. If the value is greater than zero, the visualizer linearly interpolates between consecutive frames to produce that many intermediate frames per frame. You can also press r or SHIFT+r while the visualizer is running to increase or decrease the subframe count.

Set SAMPLE_DATA_PCAP_PATH before running:

ouster-cli source {SAMPLE_DATA_PCAP_PATH} viz --subframes 10

Advanced usage with sensor¶

Running the viz command will auto-configure the udp destination of the sensor while leaving the lidar port as previously set on the sensor. If your sensor is already configured appropriately, you may find it useful to use the argument --no-auto-udp-dest to save time by skipping the round trip to reconfigure the sensor.

Congratulations! You’ve installed and visualized with the Ouster Python SDK!