ALDarknessDetection

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NAOqi Vision - Overview | API


What it does

ALDarknessDetection enables to check whether or not the robot is in a dark environment.

A darkness value is computed for each frame returned by the camera. This value is stored in the ALMemory . When the robot detects for the first time that that the environment around it is dark (i.e the darkness value is greater than a threshold) an event is raised.

How it works

This function first computes a value between 0 and 100 corresponding to the lighting conditions of the environment around the robot:

  • 0: bright environment
  • 100: dark environment

This value is then compared to a darkness threshold:

  • if it is smaller than the threshold, the surrounding environment is not considered as dark.
  • if it is greater than the threshold, the surrounding environment is considered as dark.

The darkness threshold value can be accessed with the function ALDarknessDetectionProxy::getDarknessThreshold . It has a default value of 60 but it can be changed with the function ALDarknessDetectionProxy::setDarknessThreshold .

Performances and Limitations

The camera AutoExposition parameter (and the AutoGain parameter, if it exists) of the camera must be activated for this module to work properly.