Relationship
Capturing relationships enables autonomous systems to navigate complex scenes (such as road environments) effectively, ensuring safety, efficiency, and a better user experience.
User can create relationship across sensors, if needed.
Benefits
Collision Avoidance and Safety: Understanding which object is leading and which is following helps autonomous vehicles maintain safe following distances and prevent rear-end collisions.
Accurate Behavior Prediction: Identifying leading and following objects enables the system to predict their behaviors, such as when the leading vehicle might slow down or stop, allowing the following vehicle to adjust accordingly.
Knowing which object is leading and following helps plan evasive actions during emergencies, such as sudden braking or unexpected obstacles.
Steps to use Relationship
Create relations in the recipe
It is important to create the relations in the recipe to invoke this feature on the tool. In the recipe section, user will create the relation.
Use Case 1: One-way Relations
Most (if not all) use cases fall under this category. Examples: a car atop a trailer, a rider sitting on a two-wheeler, a stroller being pushed by a pedestrian, trailer connected to the cabin of a truck, etc.
A. Select the Subject to Create a Relation
Relationship example:
Relationship 1: Subject -> Rider ; Object -> TwoWheeler
User is prompted to select a relation on the tool.
Based on the relation, the selected annotation becomes the Subject (i.e. child) in the relationship and is displayed on the left side across the tool:
under the Relationship tab
in the attribute list
As a visual cue, on the point cloud, the subject will always have the small sphere and the object will always have the big sphere.
B. Select the Object to Create a Relation
User is prompted to select a relation on the tool.
Based on the relation, the selected annotation becomes the Object (i.e. parent) in the relationship and is displayed on the right side across the tool:
under the Relationship tab
in the attribute list
As a visual cue, on the point cloud, the subject will always have the small sphere and the object will always have the big sphere.
Use Case 2: Class Has Multiple Relations
A common example would be various categories of vehicles that can be towed by a tow-truck.
Recipe used in this use case:
Relationship 1: Subject -> Rider ; Object -> TwoWheeler
Relationship 2: Subject -> Rider ; Object -> Bicycle
User is prompted to select a relation on the tool since the selected annotation can be in a relationship with two annotations.
In the example, Rider (subject) can be in a relationship with either TwoWheeler or Bicycle (two objects). The tool prompt will appear with multiple relations.
If the user had selected the object (either TwoWheeler or Bicycle), the user would not have had to choose (the relation selection would be implicit).
The relationship is displayed on the tool uniformly, where left is subject and right is object:
under the Relationship tab
in the attribute list
As a visual cue, on the point cloud, the subject will always have the small sphere and the object will always have the big sphere.
Use Case 3: Cyclic Relations
A. A Class Category is both Subject and Object
A common example is a pedestrian holding hands with another pedestrian.
Recipe used:
Relationship 1: Subject -> PassengerCar ; Object -> PassengerCar
User is prompted to select a relation on the tool. Since the subject and object are identical (PassengerCar), the tool prompt for relation will appear with options.
The selected annotation can become the Subject (child) or the Object (parent) depending on whether the relation selected was Outgoing or Incoming:
Outgoing - Selected annotation becomes the object
Incoming - Selected annotation becomes the subject
The relationship is displayed on the tool uniformly, where left is subject and right is object:
under the Relationship tab
in the attribute list
As a visual cue, on the point cloud, the subject will always have the small sphere and the object will always have the big sphere.
B. A Class Category is an Object in one Relationship and Subject in Another
A common example is a bi-articulated bus, where the centre is both a subject and an object entity.
Recipe used:
Relationship 1: Subject -> Rider ; Object -> TwoWheeler
Relationship 2: Subject -> Rider ; Object -> Bicycle
User is prompted to select a relation on the tool. Since the subject and object categories can overlap, the tool prompt for relation will appear with options.
The selected annotation can become the Subject (child) or the Object (parent) depending on whether the relation selected was Outgoing or Incoming:
Outgoing - Selected annotation becomes the object
Incoming - Selected annotation becomes the subject
The relationship is displayed on the tool uniformly, where left is subject and right is object:
under the Relationship tab
in the attribute list
As a visual cue, on the point cloud, the subject will always have the small sphere and the object will always have the big sphere.
The expert can select either the object or the subject and proceed to creating the relation in all Use Cases.
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