Telestrator

A telestrator is a device that allows its operator to draw a freehand sketch over a moving or still video image. Also known as a video marker, this device is often used in sports and weather broadcasts to diagram and analyze sports plays or incoming weather patterns. The user typically draws on a touchscreen with a finger or uses a pen on a graphics tablet. From the touchscreen or the tablet, the drawing signal is communicated to the telestrator, which overlays the video image with the drawing and outputs the combined signal for broadcast or display.

Today, the telestrator is used in a wide variety of applications (from educational, boardroom, church and military presentations to telemedicine conferences), where it can be used by both the near and far ends to annotate precise details of microscopic images or other medical images that are under consultation. The telestrator is also used in courtrooms to communicate details of multi-media images presented to a jury, as was most famously seen during the O.J. Simpson trial in March 1995.

The telestrator was invented by physicist Leonard Reiffel, who used it to draw illustrations on a series of science shows he did for public television's WTTW-ch11 in Chicago in the late 1950s. After he’d been using it to help illustrate details to his young science audience, he approached Chicago’s CBS affiliate WBBM-ch2 suggesting it be used in sports and weather. Chicago Bears football player-turned-sportscaster Johnny Morris, who worked for Channel 2, began using it as did the station’s Chief Meteorologist. According to Mr. Reiffel, “After that, New York began to hear about it, and it went on from there.”

The user interface for early telestrators required the user to draw on a TV screen with a light pen, whereas modern implementations are commonly controlled with a touch screen or a graphics tablet.

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