Abstract:
The effects of friction and vibration are eliminated from an automatically regulated iris, optical filter, or similar arrangement by employing an electroresponsive drive motor with translational drive means. Iris blades or the like are secured to flexible members, the flexure of which is varied by translational motion of the drive system in response to low-power control signals. With this construction, sliding friction is avoided and the system is virtually nonresponsive to vibration.
Abstract:
AN ELECTRORESPONSIVE LIGHT REGULATING DEVICE IS CONSTRUCTED WITH A PAIR OF LIGHT CONTROLLING ELEMENTS SUCH AS FILTERS OR IRIS BLADES MOUNTED ON A PAIR OF CANTILEVER SPRING MEMBERS. THE CANTILEVER SPRINGS ARE CONNECTED TOGETHER BY A TAUT BAND AND A METER MOVEMENT IS POSITIONED TO ENGAGE AND DISPLACE THE TAUT BAND AND THUS ALTER THE RELATION OF THE LIGHT CONTROLLING ELEMENTS.
Abstract:
The amplitude of a signal generated by a video pickup tube is controlled by employing an automatic iris at high illumination levels and an automatic gain control circuit at low illumination levels. The crossover point between iris and gain control is selected so that the gain circuit operates as long as increased illumination and decreased gain improve the signal to noise ratio and picture quality. Above this point, signal level is maintained by an automatic iris which improves the depth of field as illumination increases. Both functions are controlled by sampling a selected field of the output from the pickup tube.