Isadora Manual v1.3 - TroikaTronix

Output Properties
• video out: The exploded image.
Eyes
Tracks the position of an object in a video stream based on its brightness.
The Eyes actor will report the location of the brightest object in the video stream,
based on its location in a grid superimposed upon that video stream. It will also
report the size of the object, and its velocity (i.e. speed of movement.)
The rows and columns inputs determine the size of a grid. As each frame arrives,
Eyes analyzes the image looking for the grid coordinate that is brighter than all the
others. It then reports the position of that object.
To help you configure the Eyes inputs, turn on the monitor input. When you do, a
miniature monitor window will appear in the center of the actor. The red crosshairs
show the center of the object, and the yellow rectangle shows the “bounding box”
of the object as it is tracked.
Because displaying the monitor consumes some of your CPU speed, you should
turn it off once you have configured eyes to your satisfaction.
You may optionally set a grid location to be watched using the watch col and watch
row properties. When an object enters this grid location, the enter output will send a
trigger; when the object disappears, the exit output sends a trigger.
Generally speaking, the higher contrast the incoming video image, the easier it will
be for Eyes to track – placing a performer in a light colored costume on a black
background is ideal. You can also improve tracking by filtering the video before
you attempt to track it. The two actors that can be quite useful in this respect are
Difference and Chroma Key.
Isadora Manual
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