Behind the Curtain | Advanced projection techniques and correlate the movement of the object within the fi xed environment. This type of object tracking can be very fl exible, albeit often less precise. It works well for irregular shapes; human shapes for example, and can be seen at work in some innovative dance performances and at the Met Opera Ring cycle productions. imaging system. For example, infrared LED’s can be installed in the set to mark object boundaries, which are easily discerned by the tracking system. image layers with external data and because servers support multiple layers, it is possible to create multiple image scenarios linked to various types of tracked data. While the specifi c method varies from server platform to server platform, in general, the programmer will confi gure the system and timeline so that a given set of external data will trigger cues that affect the image layer. A typical example would see a response to external data result in the playing of a video clip sized to match to a scenic object followed by the movement of that sized video clip from one section of the pixel space to another, in synch with the scenic object. It is important to note that process of image tracking results in a loss of image resolution. This is due to the fact that the image tracking methods described here use the projector to create a large image area and then only use a portion of that image area at any one time—the image is being specifi c to where the scenic object is located. Combining tracking methods In highly complex systems, with many objects, and different types of shapes to track, an effective approach will utilize as many tracking methods as necessary to provide accurate tracking data to the imaging system. The imaging system’s ability to sense or “see” the objects can be affected by numerous factors, including lighting, patterned backgrounds, or complex movements and that can lead to inconsistency in the tracking data. To mitigate this, it is possible to add emitters to the objects to create signatures for the FALL 2011 “ “ In highly complex systems . . . an effective approach will utilize as many tracking methods as necessary to provide accurate tracking data to the imaging system. The modern image processing system for tracking The power and fl exibility of the modern media server makes it the ideal platform for tracking systems. The servers provide a conduit that allows the programmer to link 34 FALL 2011