SoftBank Robotics documentation What's new in NAOqi 2.8?

ALGazeAnalysis

NAOqi People Perception - Overview | API

What it does

ALGazeAnalysis allows you to analyze the direction of the gaze of a detected person, in order to know if he/she is looking at the robot. It also detects whether the person’s eyes are open or closed.

How it works

By detecting the face of a person and studying its orientation, it is possible to detect whether or not this person is looking at the robot.

First a scoring value, called LookingAtRobotScore, is computed for each person in the detected population. This score, between 0 and 1, describes the confidence in the fact that the person is looking at the robot. It is stored in the memory key PeoplePerception/Person/<ID>/LookingAtRobotScore. Then this score is compared to a threshold value:

  • if the score is greater than the threshold value, the person is characterized as looking at the robot.
  • if the score is smaller than the threshold value, the person is characterized as not looking at the robot.

It is possible to change the threshold value by changing the Tolerance of the gaze analysis, using the function ALGazeAnalysisProxy::setTolerance (Threshold = 1-Tolerance). The current value of the Tolerance can be retrieved with function ALGazeAnalysisProxy::getTolerance.

This result is added to the description of the people in the ALMemory by filling the key PeoplePerception/Person/<ID>/IsLookingAtRobot.

The raw head angles are also available through the key PeoplePerception/Person/<ID>/HeadAngles. The gaze direction relative to the face plane are available through PeoplePerception/Person/<ID>/GazeDirection. The “opening degree” of both eyes is given by PeoplePerception/Person/<ID>/EyeOpeningDegree.