A line or rectangle is superimposed on a video picture to direct attention to features of the picture and to indicate heights and angles of lines in the picture. Video signals are sampled to provide synchronizing triggers to timing circuits. Four timing circuits define the vertical position and height, and horizontal position and width of the rectangle or line. One additional timing circuit defines the angle the line makes with the vertical, permitting slanted lines or diamond shapes. The pulses which form the line, rectangle or diamond shape are fed back to the video system on the same cable which brought the composite signal to the hand-held video pointer circuitry. BACKGROUND OF INVENTION 1. Field The present invention relates to special effect electronic generators and in particular to video pointers superimposed on a TV monitor. 2. Description of the Prior Art Electronic pointers are used in closed-circuit TV as an educational aid in describing what is seen on the monitor. These pointers use a two cable system to communicate between the pointer and the monitor and camera with a resultant loss of the video signal on the monitor if the pointer fails or is inadvertently turned off. High power requirements have prevented design of a unit that could be held in the palm of the hand. In addition, these pointers are somewhat limited because they do not make an angle with respect to the vertical which would allow provision for a diamond shape or a simulated physical pointer. Previous devices have been limited to functions with vertical or horizontal components only. Squares, crosses, lines or boxes have been variable in size, but have always been vertical.
In a system in which there are available several pictures the device according to the invention enables the management of the overlays of pictures by implementing a mechanism according to which transition points are defined during the scanning. At these transition points, the mode of display changes. The horizontal position of these points and the nature of the display change are contained in a special register (13). An abscissa comparator (12) continuously compares the current abscissa and the abscissa indicated in the register (13) and, after an abscissa identity has been found and a new overlay mode has been set up, the next word in the register (13) is taken into account. Means (5, 8) enable the content of the register (13) to be reloaded during the line scan return periods.
