A ROS wrapper of the AprilTag 3 visual fiducial detection algorithm. Provides full access to the core AprilTag 3 algorithm's customizations and makes the tag detection image and detected tags' poses available over ROS topics: including tf.



Input List

There are 2 parameters.

Port NameMessage typeCallback
camera_infoCameraInfo [sensor_msgs-ROS1/Subscriber]
image_rectImage [sensor_msgs-ROS1/Subscriber]

Output List

There are 4 parameters.

Port NameMessage type
dependsDependency [movai_msgs-MovAI/Depends]
tag_detectionsAprilTagDetectionArray [apriltag_ros-ROS1/Publisher]
tag_detections_imageImage [sensor_msgs-ROS1/Publisher]
tfTF [movai_msgs-ROS1/Publisher]

Parameter List

There are 11 parameters.

camera_frame[string] Camera frame name.
publish_tf[bool] Enables the publishing of the tag-camera relative poses on the /tf topic.
standalone_tags[list] Standalone tag definitions.
tag_blur[double] The Gaussian blur to apply to the segmented image (used for quad detection? GGG) parameter is the standard deviation in pixels. Extremely noisy images benefit from non-zero values, such as 0.8.
tag_border[int] Width of the tag outer GGG (circumference black border).
tag_decimate[double] Quad detection can be performed on a lower-resolution image to improve speed at the cost of pose accuracy and a slight decrease in detection rate. Decoding the binary payload is still done at full resolution.
tag_family[string] AprilTag family to use for detection. Supported: tag36h11, tag36h10, tag25h9, tag25h7 and tag16h5.
tag_refine_decode[int] When non-zero, detections are refined in a way intended to increase the number of detected tags. Especially effective for very small tags near the resolution threshold (such as 10px on a side).
tag_refine_edges[int] When non-zero, the edges of the each quad are adjusted to 'snap to' strong gradients nearby. This is useful when decimation is employed because it can substantially increase the quality of the initial quad estimate. It is generally recommended to be on (1), which is very computationally inexpensive. This option is ignored if tag_decimate==1.0.
tag_refine_pose[int] When non-zero, detections are refined in a way intended to increase the accuracy of the extracted pose. This is done by maximizing the contrast around the black and white border of the tag. This generally increases the number of successfully detected tags, though not as effectively (or quickly) as tag_refine_decode.
tag_threads[int] The quantity of threads that the AprilTag 2 core algorithm should use.

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