Slow-Motion Magnetic Sheet Videocorder and its Applications

A high-quality, yet inexpensive system for recording, playing back and analyzing video images of moving objects at selectable slow rates is described. The system records monochrome images on a thin circular polyester sheet with a magnetic coating and can display real-time, slow-motion and stop-action views of motions lasting from a small fraction of a second up to 10 s. As the sheet rotates, an air cushion is created with such dynamics that the sheet stretches to generate the necessary head-to-sheet contact pressure, the video is recorded on the sheet in a continuous spiral track by a record/reproduce head that moves radially across the rotating sheet at a synchronous speed during the record mode. In playback, the head moves either synchronously or incrementally at preselected rates. Two independent stationary heads, located at the periphery of the sheet and at opposite sides, are used to record and reproduce a single field of the video signal from the main head during stop- and slow-motion operation. The mechanical and electronic subsystems of the recorder are described along with a special strobe light and a rotating-shutter video camera designed to complement the system. Two applications among the many possible are discussed: a pulsed x-ray system for medical diagnosis and the Sports Clinic System as it is used for analyzing and perfecting a golf swing.

Print ISSN

0361-4573

Published

1975-10

Content type

Original Research

DOI

10.5594/J10595