Conditional actions¶
DepthAI SDK provides a way to perform actions based on some conditions. For example, you can perform an action when a certain number of objects is detected in the frame. This functionality can be achieved by using Trigger-Action API.
Overview¶
Trigger-Action API is a way to define a set of conditions and actions that should be performed when these conditions are met. DepthAI SDK provides a set of predefined conditions and actions, but you can also define your own.
Basic concepts:
Trigger - a condition that should be met to perform an action.
Action - an action that should be performed when a trigger is met.
Note
Trigger-Action API is implemented in the depthai.trigger_action module.
Triggers¶
The base class for all triggers is Trigger.
In order to create a trigger, you need to use the Trigger class and pass the following parameters:
input- a component that should be used as a trigger source.condition- a function that should returnTrueorFalsebased on the trigger source.cooldown- defines how often a trigger can be activated (in seconds).
The set of predefined triggers:
DetectionTrigger- a trigger that is activated when a certain number of objects is detected in the frame.
Actions¶
An action can be represented by either a function or a class derived from Action class.
The custom action should implement activate() and optionally on_new_packets() methods.
The set of predefined actions:
RecordAction- records a video of a given duration when a trigger is activated.
Usage¶
The following example shows how to create a trigger that is activated when at least 1 person is detected in the frame. When the trigger is activated, it records a 15 seconds video (5 seconds before the trigger is activated and 10 seconds after).