Video signal processing apparatus with reduced noise sensitivity for low illumination and contour compensation control for high illumination

摘要

An improved video signal processing circuit employs a control signal generating device, first and second delay circuits, a signal selection circuit, an addition circuit, a subtraction circuit, and an addition/subtraction circuit. The signal selection circuit is responsive to switch control signals from the control signal generating device for selecting a first signal path when providing signal contour compensation or a second signal path when functioning as a sensitivity enhancement device. At the final output terminal of the present circuit is produced a contour-compensated luminance signal under medium or high illumination selection control and an enlarged luminance signal without noise under low illumination selection control. Mode change is a function of and dependent on the amount of incident light to be automatically achieved by the control signal generating device.