29 Jun 2002 motters   » (Master)

After a certain amount of faffing about I've managed to get Rodney's slow speed visual tracking working. I managed to overcome the competing optical flows problem by ignoring the actual velocity of the target and just using its distance from the centre of the camera's coordinates as the error signal.

First I tested the tracking only on one axis (head pan). This worked ok, so I've also done the same for the eyes tilt axis. There are other axes, such as neck tilt, which I could include but I really want to keep the head movements to a minimum and as smooth as possible to that the target isn't lost due to camera shake. There is some slight shakiness in the very slow speed movements of the head, but this is probably inevitable given the rather crude way in which the miniSSC controller works.

To make the visual tracking a little more reliable I've increased the size of the local region within which the program searches for matches, and upped the sampling resolution a little.

Of course this type of tracking is only for slow moving objects. For things which move faster the robot needs to use a different, so-called "ballistic", tracking system. Here the system determines the position error and then does a fast move of the head, ignoring anything which is seen during the move (mostly just blur).

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