radar_object_clustering#
This package contains a radar object clustering for autoware_auto_perception_msgs/msg/DetectedObject input.
This package can make clustered objects from radar DetectedObjects, the objects which is converted from RadarTracks by radar_tracks_msgs_converter and is processed by noise filter. In other word, this package can combine multiple radar detections from one object into one and adjust class and size.
Algorithm#
Background#
In radars with object output, there are cases that multiple detection results are obtained from one object, especially for large vehicles such as trucks and trailers. Its multiple detection results cause separation of objects in tracking module. Therefore, by this package the multiple detection results are clustered into one object in advance.
Detail Algorithm#
- Sort by distance from
base_link
At first, to prevent changing the result from depending on the order of objects in DetectedObjects, input objects are sorted by distance from base_link.
In addition, to apply matching in closeness order considering occlusion, objects are sorted in order of short distance in advance.
- Clustering
If two radar objects are near, and yaw angle direction and velocity between two radar objects is similar (the degree of these is defined by parameters), then these are clustered.
Note that radar characteristic affect parameters for this matching.
For example, if resolution of range distance or angle is low and accuracy of velocity is high, then distance_threshold parameter should be bigger and should set matching that strongly looks at velocity similarity.
After grouping for all radar objects, if multiple radar objects are grouping, the kinematics of the new clustered object is calculated from average of that and label and shape of the new clustered object is calculated from top confidence in radar objects.
- Fixed label correction
When the label information from radar outputs lack accuracy, is_fixed_label parameter is recommended to set true.
If the parameter is true, the label of a clustered object is overwritten by the label set by fixed_label parameter.
If this package use for faraway dynamic object detection with radar, the parameter is recommended to set to VEHICLE.
- Fixed size correction
When the size information from radar outputs lack accuracy, is_fixed_size parameter is recommended to set true.
If the parameter is true, the size of a clustered object is overwritten by the label set by size_x, size_y, and size_z parameters.
If this package use for faraway dynamic object detection with radar, the parameter is recommended to set to
size_x, size_y, size_z, as average of vehicle size.
Note that to use for multi_objects_tracker, the size parameters need to exceed min_area_matrix parameters of it.
Limitation#
For now, size estimation for clustered object is not implemented.
So is_fixed_size parameter is recommended to set true, and size parameters is recommended to set to value near to average size of vehicles.
Input#
| Name | Type | Description |
|---|---|---|
~/input/objects |
autoware_auto_perception_msgs/msg/DetectedObjects.msg | Radar objects. |
Output#
| Name | Type | Description |
|---|---|---|
~/output/objects |
autoware_auto_perception_msgs/msg/DetectedObjects.msg | Output objects |
Parameters#
| Name | Type | Description | Default value |
|---|---|---|---|
angle_threshold |
double | Angle threshold to judge whether radar detections come from one object. [rad] | 0.174 |
distance_threshold |
double | Distance threshold to judge whether radar detections come from one object. [m] | 4.0 |
velocity_threshold |
double | Velocity threshold to judge whether radar detections come from one object. [m/s] | 2.0 |
is_fixed_label |
bool | If this parameter is true, the label of a clustered object is overwritten by the label set by fixed_label parameter. |
false |
fixed_label |
string | If is_fixed_label is true, the label of a clustered object is overwritten by this parameter. |
"UNKNOWN" |
is_fixed_size |
bool | If this parameter is true, the size of a clustered object is overwritten by the label set by size_x, size_y, and size_z parameters. |
false |
size_x |
double | If is_fixed_size is true, the x-axis size of a clustered object is overwritten by this parameter. [m] |
4.0 |
size_y |
double | If is_fixed_size is true, the y-axis size of a clustered object is overwritten by this parameter. [m] |
1.5 |
size_z |
double | If is_fixed_size is true, the z-axis size of a clustered object is overwritten by this parameter. [m] |
1.5 |