Victor Company of Japan, Limited

Hiroshi Ichimura

Shintaro Nakagaki

Itsuo Takanashi

Takashi Kuriyama

Ichiro Negishi

Tsutou Asakura

Masaru Osada

Hiroki Kitamura

Wataru Katase

Kaoru Kitami

Ikumi Minema

A dc-dc converter for converting first to second dc voltages, used for video apparatus, comprising: a self-excited oscillation circuit for producing a clock signal, the self-excited oscillation circuit having a control input for controlling oscillation thereof in response to a control signal; a pulse width modulation circuit responsive to the clock signal and the second dc voltage for controlling duty ratio of the clock signal; a switching circuit responsive the pulse-width-modulated clock signal for switching the first dc voltage; rectifying and smoothing circuit for rectifying and then smoothing an output of the switching circuit to produce the second dc voltage; and a control circuit responsive to a vertical synchronizing signal of a video signal used in the video apparatus for producing the control signal whose pulse width is sufficiently shorter than a vertical retrace period of the vertical synchronizing signal. Oscillation of the self-excited circuit is controlled in response to the vertical synchronizing signal to prevent switching noise of the dc-dc converter from disturbing the reproduced image.

dc-dc Converter for video apparatus

A color separation stripe filter in a color image pickup apparatus in which a color image is focused on a photo-electric conversion target through the filter to be converted to an electrostatic image so as to generate a color multiplexed signal. The filter comprises a plurality of recurrent groups of three different color stripes successively arranged at periodic intervals. The first color stripe has a characteristic showing a peak transmission factor in a red color region, the second color stripe has a characteristic showing a peak transmission factor in a green color region which is substantially equal to the peak transmission factor of the first color stripe, and the third color stripe has a characteristic showing a negative peak transmission factor at a wavelength between 500 nm and 530 nm so as to produce first and second peak transmission factors in a blue region and said green region. The first peak transmission factor is substantially equal to each of the peak transmission factors of the first and second color stripes and the second peak transmission factor existing in the green color region to be 50% to 80% of each of the peak transmission factors of the first and second color stripes, a curve of the characteristic of the third color stripe in the green region being substantially similar in configuration to that of the second color stripe.

Color stripe filter in color image pickup apparatus

A color filter has a plurality of succesively arranged recurrent groups of different color stripes. An image pickup tube has a photoelectrical conversion target exposed to light passing through the color filter and an index signal generation pattern. The image pickup tube outputs a signal containing a color signal component determined by a carrier which is modulated with the individual color stripes of each recurrent group of the color filter. The output signal from the image pickup tube also contains an index signal component which depends on the index pattern. A first memory holds at least part of the index signal component. The index signal component held by the memory is periodically updated. A second memory holds a portion of the output signal from the image pickup tube which was obtained under conditions where a predetermined color light illuminates the photoelectrical conversion target via the color filter. A reference signal is generated in accordance with the index signal component read from the first memory and with the signal portion read from the second memory. A color signal is detected from the output signal of the image pickup tube by use of the reference signal.

Color imaging apparatus including control system for stabilizing phase

A color filter has recurrent groups of different color stripes. An image pickup tube has a photoelectrical conversion target exposed to light passing through the color filter and an index signal generation pattern. The image pickup tube outputs a signal containing a color signal component and an index signal component which depends on the index pattern. The index signal component has a phase representing a present start position of each scanning line. A memory holds a portion of the output signal from the image pickup tube corresponding to an initial frame period which occurs under conditions where a predetermined color light is applied to the photoelectrical conversion target via the color filter. A reference signal reflects a signal read out from the memory. A color component is detected from the output signal of the image pickup tube by use of the reference signal. The reference signal contains an index signal component which has a phase representing a start position of each scanning line during the initial frame period. A closed-loop phase control system allows the present start position of each scanning line to remain essentially equal to the start position of the corresponding scanning line during the initial frame period. A phase or level shifter is interposed in a loop of the closed-loop phase control system.

Color imaging apparatus including phase control system for maintaining

A single tube color video camera apparatus having a camera tube including a color separation stripe filter and producing an output signal containing a color multiplex carrier signal, utilizes an envelope detector for directly detecting the camera tube output signal to produce an envelope detection signal which varies in accordance with an electrical charge pattern of the tube target. Phase control of the color multiplex carrier signal extracted from the camera tube output signal is executed based upon the envelope detection signal, to thereby correct for color signal phase deviations caused by variations in light intensity of scenes viewed by the camera.

Color video camera apparatus providing correction of light

A color image pickup device comprises an image pickup tube, a color stripe filter comprising a plurality of stripes, a circuit for obtaining a color multiplexed signal by multiplexing color components obtained via the color stripe filter in a direction perpendicular to a scanning direction of the image pickup tube, and a circuit for producing a color demodulated signal by subjecting the color multiplexed signal to a color demodulation. The color stripe filter is arranged on the image pickup tube so that a longitudinal direction of the stripes thereof is substantially parallel to the scanning direction.

Color television image pickup device with a stripe filter parallel to

A color image pickup device comprises an image pickup tube, a color stripe filter comprising a plurality of stripe groups each having a plurality of stripes, and a circuit for obtaining a color multiplexed signal by multiplexing color components obtained via the color stripe filter in a direction perpendicular to the scanning direction for every one stripe group. The color stripe filter is arranged on the image pickup tube so that a longitudinal direction of the stripes of the color stripe filter is substantially parallel to a scanning direction of the image pickup tube. A color demodulated signal and/or a luminance signal are/is produced from the color multiplexed signal.

A color image pickup device comprises an image pickup tube, a color stripe filter comprising a plurality of stripes, a circuit for obtaining a color multiplexed signal by sampling color information from the color stripe filter and multiplexing color components obtained by the sampling in a direction perpendicular to the scanning direction, and a circuit for producing a color demodulated signal by subjecting the color multiplexed signal to a color demodulation. The color stripe filter may be arranged on the image pickup tube so that a longitudinal direction of the stripes is approximately parallel to a scanning direction of the image pickup tube, and the sampling may be performed at sampling points which are deviated in the scanning direction for each scanning line. On the other hand, the color stripe filter may be arranged so that the scanning direction is inclined by a certain angle with respect to the longitudinal direction of the stripes so that an interval between two mutually adjacent sampling points on each scanning line along a direction approximately perpendicular to the scanning direction is within a repetition pitch of the scanning lines.

In a color imaging apparatus, an optical image is focused on a photoelectrical conversion target of a color image pickup tube through a color stripe filter and converted to an electrostatic image, the latter being scanned line-by-line in rectangular raster form by an electron beam to generate a color multiplexed video signal. First and second index stripe electrodes are located adjacent to edges of the raster area to be scanned at the beginning of each field and at the beginning of each line. A memory is provided to store field and line index signals generated by the index electrodes as well as a reference video signal generated by the target illuminated with light of a predetermined color. During normal viewing operations, the stored signals are retrieved from the memory for frequency and phase comparison with signals generated by the index electrodes and the target to control the phase relationship between the retrieved reference video signal with the color-multiplexed video signal to effect synchronous detection therebetween at proper timing to produce primary color signals. The retrieved index signals prevent the loss of proper timing when the target is dimly illuminated.

Color imaging apparatus with closed-loop control means for producing

In a color imaging apparatus, an optical image is focused on a photoelectrical conversion target of a color image pickup tube through a color stripe filter having a plurality of successively arranged recurrent groups of different color stripes and converted to an electrostatic image which is scanned in rectangular raster form by an electron beam to generate a luminance signal and a color-multiplexed video signal. The leading and trailing edges of the luminance signal are detected by an edge detector to generate a control signal having first and second polarities in response to the detection of the leading and trailing edges, respectively. The color multiplexed signal is phase-controlled with respect to the leading and trailing edges of the luminance signal in accordance with the control signal by a variable delay line or by a pair of beam deflection plates.

Transitory scanning speed phase compensation using luminance edge

In a single-tube color image pickup apparatus, an optical image is passed through a color stripe filter having recurrent groups of different color stripes to a photoelectrical conversion target, which is scanned by an electron beam to generate a video signal comprising a carrier having a frequency inversely proportional to the intervals at which the recurrent groups of filter strips are arranged. The carrier is modulated in phase with the stripes of each group and in amplitude with the intensity of the optical image. Prior to operation, the target is uniformly illuminated with light of a predetermined color to generate the carrier, which is stored into a field memory. During operation the memory is repeatedly addressed to generate a reference signal. The frequency of the reference signal is converted so that the video signal and the frequency-converted reference signal have a frequency ratio of 1:2 and an opposite phase relationship therebetween. A color demodulator receives these signals to derive a pair of color component signals for coupling to a matrix circuit to which a luminance component is also applied.

Color imaging apparatus having a 1:2 frequency ratio between video and

A feedback control loop for controlling the intensity of a scanning electron beam of an image pickup tube of a color TV camera which is especially useful in a single tube color TV camera with a stripe filter, comprises an envelope detector for detecting the envelope of an output video signal derived from the image pickup tube. An envelope signal from the envelope detector is then compared with a reference threshold by a comparator so that a voltage applied to a control grid of the pickup tube is controlled in accordance with the amplitude of the envelope signal, thereby increasing the intensity of the scanning electron beam applied to a portion of a photoelectric converting layer when the brightness at the portion is high. As a result, an ideal multi-color output video signal is obtained irrespective of the brightness of a subject to be taken even if the intensity of the scanning electron beam is usually set to a relatively low value. In one embodiment, a circuit for amplifying high-frequency components of the output video signal is employed for compensating for a modulation characteristic of typical pickup tubes having a poor high frequency response.

Automatic beam current control with an envelope detector for a color

In a single-tube color imaging apparatus, the pickup tube includes a photoelectrical conversion target and a filter having recurrent groups of different color stripes through which an optical image is passed to the target. The target is scanned by an electron beam to produce a video signal having a frequency inversely proportional to the intervals at which the recurrent groups are arranged. The video signal varies in phase with the relative values of primary color components contained in the image passing through the stripes of each group and in amplitude with the intensity of the primary color components. Prior to normal operation, the target is uniformly illuminated with light of a predetermined color to generate a reference video signal, which is stored in a field memory. During normal operation, the reference signal is repeatedly read out of the memory and compared by frequency and phase comparators with the video signal from the target. Frequency and phase control circuitry responds to the outputs of the comparators by controlling the frequency and phase relationships between the two signals so that they match in frequency and phase before being applied to synchronous detectors.

Color imaging apparatus with compensation for beam deflection

A color television signal generating apparatus has a noise reduction circuit for reducing noise in output primary color signals of a camera tube which has a color-resolving striped filter. The noise reduction circuit operates so that the noise included in the color signals only consists of cosine terms of a first-order noise component when a white or magenta image is picked up by the camera tube.

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Tokyo, Japan

Hiroshi Ichimura