Abstract: A chroma keyer with fringe control offset adds a fringe control offset value to a correlation output produced by a hue selector. The hue selector compares the hues of a foreground image, representing a foreground object in front of a reference matte background, with a reference hue corresponding to the reference matte background to produce the correlation output. The adjusted correlation signal is then negatively clipped and provided at the output of the hue selector as a hue select signal that is used for deriving a chroma key signal and for providing background suppression to the foreground image.

Abstract: In a ghost detector, synchronous detection is performed on a received video signal to provide a detected signal which is then converted to a band-limited signal having a predetermined bandwidth, a scanning synchronous component signal is extracted from the detected signal to provide a switching control signal for a ghost component detecting period on the basis of the synchronous component signal, and the band-limited signal is switched in response to the switching control signal so as to provide a switching signal.

Abstract: An AGC system for use in positive modulation schemes of video signals is provided. The AGC system utilizes an IF amplifier, a demodulator, a video amplifier, a gated amplifier and a peak detector. The gated amplifier has a first, relatively fast, time constant associated therewith. The gated amplifier, which is activated during the time interval that the black voltage appears on the video signal, is responsive to an intial reference voltage and to the video signal for providing an output signal to control the gain of the IF amplifier. The peak detector has a second, relatively slow, time constant associated therewith. The peak detector is used to detect the peak white voltage level of the video signal to adjust the initial reference voltage to account for fluctuations and errors in the peak white voltage level.