Abstract: A focus detection signal is generated from the video signal produced by a video camera by deriving higher frequency components of that video signal, detecting when those higher frequency components exceed a minimum threshold level, sensing when the video signal exceeds a maximum threshold, and integrating those higher frequency components which exceed the minimum threshold, except during an interval when the video signal exceeds the maximum threshold, thereby producing the focus detection signal.

Abstract: In a color video camera providing color video signal components corresponding to a light image projected on an image pickup, only the levels of the color video signals components which correspond to at least substantially white regions of the light image are detected, and such detected levels of the color video signal components are integrated so as to obtain average values thereof as white-balance detection signals. The color video signal components which correspond to at least substantially white regions of the light image, and thus have their levels detected, may be those which occur during intervals corresponding to a white-balance detecting area positioned to correspond with a selected white area of the light image. Alternatively, the color video signal components may be sampled to provide pixel-by-pixel values thereof, whereupon, only those pixel-by-pixel values which are determined to be within a predetermined range of white as defined by a black body radiation curve are subjected to integration.

Abstract: A sampling frequency conversion filter circuit permits the same auto focus circuit to be used with CCD imagers having different numbers of pixels per line.

Abstract: A color video camera providing a digital video signal has an auto-focus detector, an auto-exposure detector and an auto-white balance detector formed as sections of an optical detector circuit which further has serial input and output ports common to the auto-focus, auto-exposure and auto-white balance detectors, and a system controller which is common to the auto-focus, auto-exposure and auto-white balance detectors and provides control signals therefor through the serial input port while receiving focus, exposure and white-balance detection signals through the serial output port from the respective detectors. Further, an improved exposure control system is provided which compensates for abnormal lighting conditions, such as, back-lighting or excessive front-lighting of the scene in the field of view of the camera.

Abstract: Apparatus is provided for controlling the aperture of an iris in a camera, such as a television camera. Samples of an image signal produced during a predetermined interval that have magnitudes greater than a threshold level are counted, and the difference between this count and a predetermined count is determined. The aperture of the iris is controlled as a function of this difference.

Abstract: In an automatic white balance control circuit for adjusting gain levels of a plurality of color signals included in a video signal composed of successive fields and received from a video camera while a light source provides illumination for the scene in the field of view of the camera; first, second and third integrators generate integration signals for each of the received color signals in each of first, second and third fields, respectively, a control signal for each of the fields is generated on the basis of the respective integration signals, and gain levels of at least two of the color signals are adjusted in response to the control signal so as to perform white balancing for preventing variation in video signal brightness or flicker, such as is caused by a difference between the video camera exposure frequency and the light source power supply frequency.

Abstract: In a camera having a lens for focussing incident light onto a light reception surface of a pick-up so that the latter outputs a camera signal, a stop for limiting the amount of the incident light, and a variable gain amplifier for correcting the level of the camera signal; there is provided a control circuit which controls a focus of the lens, the stop and a gain of the variable gain amplifier on the basis of the output of the variable gain amplifier, thereby simplifying the construction of the camera as a whole.

Abstract: In a luminance signal forming circuit, output signals from a color television camera having complementary color filters are subjected to a matrix operation to provide a first luminance signal of good luminance reproducibility, but having a relatively low signal-to-noise (S/N) ratio, and the output signals from the camera are further simply mixed to form a second or pseudo luminance signal of relatively poor signal fidelity but having a relatively high S/N ratio. The first and second luminance signals are subjected to first and second gamma corrections, respectively, which provide a first gamma characteristic having an inclination less than that for the usual or normal gamma value, while the second gamma correction provides a characteristic having an inclination substantially smaller than that of the first gamma characteristic.

Abstract: A solid-state image sensor with a color separation, filter generates a luminance signal component and line-sequential color-difference signal components. Low-pass filters produce wide-band and narrow-band luminance signals from the luminance signal component. A synchronous detection circuit, a delay circuit, and a switching circuit produce simultaneous color-difference signals from the line-sequential color-difference signal components. A level control circuit adjusts the white balance of red, green, and blue signals produced from the narrow-band luminance signal and the simultaneous color-difference signals. A narrow-band luminance signal and simultaneous color-difference signals produced from the white-balanced red, green, and blue signals together with the wide-band luminance signal are encoded into a color video signal.