sensor_filters

This package is a collection of ROS 2 nodes and composable components that run a filters::FilterChain for message types from the sensor_msgs package. See the filters package documentation to learn more about the filter chain infrastructure.

Attention: The PCL filters provided by package pcl_ros are not “compatible” with this package. They are instances of PCL filters, but written as ROS components/nodes, not as ROS filters implementing the filters::FilterBase<> interface required by this package.

The task of each filter chain node in sensor_filters is very simple: load the filter chain, subscribe to the input topic, and publish the filtered messages on the output topic.

Most behavior is configured via ROS 2 parameters declared on the node:

QoS settings of the input and output topic can be tuned via the standard qos_overrides mechanism (see the example filter.yaml below).

Provided executables

For each supported sensor_msgs type the package builds two executables and two composable components: the plain node <type>_filter_chain and its lifecycle counterpart <type>_filter_chain_lifecycle.

Features

Lifecycle support

For every chain executable, a managed (lifecycle) variant suffixed with _lifecycle is also available. Use the lifecycle CLI to drive its states. The lifecycle node only subscribes/publishes while in the active state; deactivating it stops the data flow without destroying the chain.

Lifecycle component nodes are also available named like sensor_filters::LifecycleBatteryStateFilterChainNode.

Transport support

Filters operating on Image and PointCloud2 messages automatically use image_transport and point_cloud_transport respectively to publish and subscribe to topics. The input transport can be selected with the image_transport / point_cloud_transport parameter.

PointCloud2 transport uses SensorDataQoS by default for publications (in most cases). However, it is not a good fit for filters which are usually treated as reliable chains. Therefore, the PointCloud2 filter defaults to reliable publishers. If you need to use unreliable publishers by default, either use standard QoS overrides or set parameter default_best_effort_publisher to true. For symmetry, there is also parameter default_best_effort_subscription to control the subscriber side.

Lazy subscription

Setting is_lazy: true causes the node to subscribe to the input topic only when there is at least one subscriber connected to the output topic. As soon as the last output subscriber disconnects, the input subscription is dropped, which is especially useful for filters that do expensive processing.

This requires ROS 2 Iron or newer (matched-event callbacks).

Content filtering

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Changelog for package sensor_filters

2.0.0 (2026-06-24)

• Added integration tests.
• Fixed license issues, made the repo REUSE-compliant.
• Added support for lazy input topics.
• Added support for content filters on subscriber.
• Allow overriding QoS settings.
• Add new message types for joy feedback array, fluid pressure, illuminance and other
• Use node interfaces in transport-based chains if available.
• Add image and pointcloud2 filter chains
• Add lifecycle nodes
• Port to ROS 2
• Contributors: Martin Pecka, solonovamax

1.1.1 (2023-06-07)

• Reformatted, added catkin lint.
• Simplified the license statements.
• Contributors: Martin Pecka

1.1.0 (2023-05-29)

• Using image_transport and point_cloud_transport where applicable.
• Noetic compatibility.
• Improved README and added example files. Closes #1.
• Contributors: Martin Pecka

1.0.5 (2021-07-30)

• Fixed typo leading to segfaults when using ChangeHeader filter.
• Contributors: Martin Pecka

1.0.4 (2021-06-24)

• Added ChangeHeader filter
• Contributors: Martin Pecka

1.0.3 (2021-05-20)

• Fixed data types of nodes.
• Contributors: Martin Pecka

1.0.2 (2021-05-20)

• Fix for Noetic.
• Contributors: Martin Pecka

1.0.1 (2021-05-19)

• Initial version.
• Contributors: Martin Pecka