Developments in closed-circuit television

THE development of closed-circuit television (TV) has been marked by many fascinating applications but, until recently, economic factors ruled out its mass usage in many fields. In industry, education, business, and the military, television has been a fascinating medium to explore, test, and evaluate, but only infrequently could its proponents justify its introduction on a permanent large-scale basis. Recently, however, advances in two fields have made this possible.