Closed-Loop Tracking

In these experiments I can control the pan and tilt degrees of freedom of my virtual camera. After a forced translation of the camera (for instance, it is placed on top of a moving robot) I want to control the orientation of camera in order to track the central point of the template. I defined a simple second order dynamic model for the pan/tilt motion and control these joints using simple proportional controllers. Therefore the control is not "one step" but instead has a lag that depends on the velocity of the camera and the dynamical parameters of the pan/tilt joints.

In these experiments the displacement of the camera can be larger than in the open-loop experiments because the gaze is controlled in order to have the template almost always in the field of view.

Six experiments are presented:

1. Horizontal translation parallel to the scene plane
2. Translation perpendicular to the scene plane (towards the plane)
3. Translation perpendicular to the scene plane (away from the plane)
4. Vertical translation parallel to the scene plane
5. Diagonal translation (covering all directions)
6. Elliptic trajectory (covering all directions)

For each situation we show:

• 3D plots showing the trajectory of the camera.
• A picture showing the estimated position of an arbitrary window in the image for all time steps.
• Plots for the time evolution of pan/tilt angles and the image error.
• A video showing the sequence of images observed by the camera and the estimated position of the window.
• A video showing the sequence of registered image at each time step.

 Table of the results: