Abstract: A level compression and/or gradation conversion of a video signal are performed without causing any change in the hue of a picture represented by that video signal. The knee compression and/or gradation conversion are carried out by multiplying red, green and blue primary color signals by a luminance gain, while the hue and saturation remain unaffected. If the level of any of the primary color signals still exceeds a predetermined threshold level, the saturation conversion is executed by using the saturation gain and the luminance component supplied from a controller. In the saturation conversion operation, the maximum level of at least one of the red, green and blue primary color signals is made coincident with the predetermined threshold level while the hue and luminance of the picture represented by the video signal are maintained unchanged.

Abstract: In controlling the gain of plural color signals, for the purpose controlling the white balance of a video signal released from an image pickup device and including the abovementioned plural color signals, there is provided a calculation circuit for calculating color temperature information according to the plural color signals and forming a gain control signal according to the color temperature information, and the variable range of the gain control signal is set at one of mutually nonoverlapping plural ranges, whereby the correction error of the white balance is rendered visually inconspicuous.

Abstract: A color display with a white balance self-adjusting function, including a DC-voltage-level/gain adjusting circuit for adjusting, on the basis of adjustment data, the DC voltage level and the gain of each of R, G and B primary color signals, thereby outputting the adjusted signals. Also includes is a CRT driving circuit responsive to the output signals of the DC-voltage-level/gain adjusting circuit for outputting CRT driving signals to drive the color CRT of the display, and a cathode current detecting circuit for detecting currents flowing through the cathode electrodes of the color CRT.

Abstract: The image reading device has a white level correction coefficient calculation processor, in which a white level correction coefficient, used when performing a shading correction, is calculated for each pixel data outputted from a line sensor. An exposure measurement is performed so that a color correction coefficient is calculated. A combined correction coefficient, i.e. a product of the white level correction coefficient and the color correction coefficient is obtained, and a pre-scanning operation is performed to obtain pixel data. The pixel data is multiplied by the combined correction coefficient, so that the shading correction and the color correction are performed simultaneously as a combined correction.

Abstract: A liquid crystal display ("LCD") projection unit (12) employs a luminance and color balance system having a lookup table (100) storing multiple sets of gain and/or gamma corrected responses (92-99) for color balance and luminance control. The lookup table values are determined by measuring an S-curve response (90) of an LCD array (40) for each of a set of R, G, and B input data values, converting the S-curve responses to a corresponding set of gamma responses, and scaling the gamma responses to generate red ("R"), green ("G"), and blue ("B") families of gain and gamma corrected values. Color balance is adjusted by selecting the particular R, G, and B families of gain and gamma corrected values that cause the LCD projection unit to match a predetermined ratio of maximum R, G, and B luminance values. Luminance is adjusted by selecting families of lookup table values that adjust the transmittance of the LCD while maintaining the color balance.

Abstract: A color correction device, for strengthening or weakening a specific color according to the selection of a user, is provided. In a color correction device, the area of an input color signal is determined according to chrominance axes, coefficients of a corresponding coordinate of the chrominance axes are read from a storage memory, and a matrix operation is performed on the input color signal before it is output. An index table divides the area defined by chrominance axes on the basis of r, g, and b signals. A storage memory contains coefficients corresponding to the respective coordinate positions for correcting the color signal to represent colors similarly to the original color of the subject. A specific color may be strengthened or weakened based on the selection of a user, due to the addition of a second storage memory which contains, coefficient tables for designating areas according to the chrominance axes corresponding to a color to be strengthened or weakened.

Abstract: An image sensing apparatus includes an image sensor for sensing an optical image and converting the optical image into an electrical signal, and a white balance control circuit for controlling a white balance condition of the electrical signal. A limiting device limits a control range of the white balance control circuit, and a changeover switch changes over the limiting device to selectively change the control range of the white balance control circuit.

Abstract: An imaging device includes an imaging device for converting an image into a plurality of color signals each having a signal level; a white balance amplifier for adjusting the signal level of at least one color signal to produce a plurality of amplified color signals; a calibration device for calibrating the white balance amplifier and for producing at least one calibration parameter; a detecting device for detecting the amplified color signals; a calculation device for calculating at least one white balance amplification adjustment as a function of the plurality of amplified color signals; a comparing device for comparing at least one white balance amplification adjustment with at least one calibration parameter; and an automatic adjustment device for automatically adjusting the white balance amplifier to amplify the signal level of at least one of the plurality of color signals if at least one white balance amplification adjustment is consistent with at least one calibration parameter.

Abstract: A color signal processing circuit of a camera DSP chip for use with a CCD includes a matrix circuit for converting color signals from the CCD into R-G and B-G signals, a hue/gain controlling circuit for multiplying the R-G signal by a R-hue coefficient and a R-gain coefficient and multiplying the B-G signal by a B-hue coefficient and a B-gain coefficient to form B-Y and R-Y signals by adding the R-G and B-G signals respectively multiplied by respective hue and gain coefficients, a zoom-processing circuit for zoom-processing the B-Y and R-Y signals converted in the hue/gain controlling circuit in a zoom mode, and a frequency converting circuit for synchronizing the B-Y and R-Y signals from the hue/gain controlling circuit or zoom-processed in the zoom-processing circuit with a clock having the frequency four times as large as a color burst signal to provide synchronized signals while loading the color burst signals.

Abstract: An apparatus for correcting a chromaticity diagram by a variable brightness includes: a first grid voltage controller for controlling a first grid voltage to be a voltage of a predetermined level; a first grid voltage detector for detecting the first grid voltage output by the first grid voltage controller; a phase inverter for inverting a phase of a voltage signal detected by the first grid voltage detector; an analog-to-digital converter for converting the inputted voltage signal, which has been phase-inverted by the phase inverter, into a digital signal; a microprocessor for receiving the digital data of the first grid voltage output from the analog-to-digital converter to produce and output error data; a digital-to-analog converter for converting the error data supplied from the microprocessor into an analog signal, and a cut-off controller for receiving the analog signal output from the digital-to-analog converter and correcting a color-difference signal.

Abstract: A test image 40 for determining a gamma value has a plurality of first gradation patterns 20 and a plurality of second gradation patterns 30. The patterns 20 and 30 are arranged alternately in a vertical direction. In each pattern 20, a relative brightness linearly increases from left to right. In each pattern 30, a relative brightness linearly decreases from left to right.

Abstract: A film image, which is taken into the developed photographic film, is picked up, and a reference maximum value and a reference minimum value of an image signal are determined by the image signal which is obtained when the image is picked up. The reference maximum value and the reference minimum value are used in the signal processing for adjusting the tone of the image, etc. Moreover, the exposure state of the film image is determined based on at least one of the reference maximum value, the reference minimum value, and the average value. If the exposure state is determined to be underexposured, the gamma in the gamma correction is smaller than the gamma during the standard exposure, so that the middle tone can be prevented from being dark. On the other hand, if the exposure state is determined to be overexposured, the gamma in the gamma correction is larger than the gamma during the standard exposure, so that the middle tone can be prevented from being too bright.

Abstract: Physiological primary colors, which correspond to tristimulus values of each of picture elements of an image on a hard copy, are obtained. A parameter, which represents the degree of incomplete chromatic adaptation, is determined in accordance with a correlated color temperature of a white point of a CRT display device, on which the image is to be displayed. Temporary tristimulus values, which are to be reproduced on the CRT display device, are derived in accordance with the parameter. From the temporary tristimulus values, perception values relating to lightness, color vividness and hue, such as metric lightness, metric chroma, and a metric hue angle in the LAB-color space are calculated by taking the white point of the CRT display device as a viewing illuminance. The tristimulus values of the image are then transformed into the tristimulus values on the display device, and a soft copy image is formed on the display device in accordance with the transformed tristimulus values.

Abstract: A method for correcting a color video signal for white balance comprising the steps of:providing a digital color image signal having a sequence of monocolor pixels, wherein each of the pixels represents one color of first, second, and third different colors, which are repeated in a preset pattern;coarse white balance processing each monocolor pixel for a coarse white balance;spatial processing the sequence of monocolor pixels to produce a sequence of tricolor pixels, wherein each of the tricolor pixels represents the first, second, and third different colors; andcolor correction and fine white balance processing each of the tricolor pixels by means of a matrix multiplier for color correction and fine white balance.

Abstract: A fill-in light emitting apparatus having an illuminating mechanism for emitting illumination light whose color temperature can be varied; a color temperature metering mechanism for measuring the color temperature of the external light; and a color temperature controlling mechanism for varying the color temperature of the illumination light in accordance with color temperature data measured by the color temperature metering mechanism.

Abstract: A sterile disposable white balance box including a housing of a pure white color having a bore formed therein. Also included is a penetrable seal formed about the bore of the housing whereby the seal is adapted to be penetrated by a scope rod whereupon a seal is afforded about a periphery of the scope rod.

Abstract: A color printing system includes a central processing unit for generating color image data, a color monitor for displaying color image data generated by the central processing unit and a color temperature sensing device for sensing color temperature of viewing light in which color images displayed on the monitor and color images printed by the printer are viewed. A first light source has a light output intensity controllable by the central processing unit. The central processing unit is adapted to control the intensity of the first light source in accordance with the color temperature sensed by the sensing device so as to match the color temperature sensed by the sensing device to a potential color temperature. Additionally, a second light source may be provided. The second light source has a different color temperature than the first light source and the central processor can adjust the intensity of the first and second light source based on relative color temperatures.

Abstract: In determining a color temperature in a color display device, the present invention comprises the steps of: producing a patch set I composed of a plurality of patches which appear gray under respective illuminant components and producing a patch set II composed of a plurality of patches to be a metameric pair with a neutral gray emitted from the respective illuminant components, under a specific illuminant; visually detecting peripheral illuminant components by selecting patch having identical color to that of patch having an equivalent energy spectral reflection degree in the patch set I; and determining a color temperature of the display device from the patch set II by using the detected illuminant component. Thus, the present invention provides color temperature information in producing a profile of the device required by a CMS by determining the color temperature of the display device considering the peripheral illuminant component without using a colorimeter.

Abstract: A cathode current detecting method wherein both a highlight detection pulse used to detect a white component and a cutoff detection pulse used to detect a black component are input to a signal input unit, and a cathode current flowing through a cathode is detected which corresponds to one of the highlight detection pulse and the cutoff detection pulse, includes the steps of: outputting a leak current detection pulse having the same magnitude as that of the cutoff detection pulse at a preselected timing; prohibiting an electron beam emitted from the cathode from flowing through an anode at the preselected timing; and detecting the leak current flowing through the cathode in response to the leak current detection pulse at the preselected timing to clamp a voltage corresponding to the leak current to a predetermined reference potential.

Abstract: A method of adjusting color temperature of images displayed by a display system (10) whose images are based on sequential pixel data and are filtered with a color wheel (15, 15', 15"). The relative display times for each color are adjusted to result in a corresponding adjustment of color temperature. In a first embodiment (FIG. 2), the size of the color wheel's segments are changed as well as the display times for data corresponding to each segment. In a second embodiment (FIG. 3), the display times for data corresponding to one or more segments are decreased with a black display time to fill in the difference.

Abstract: A color picture display apparatus is provided having a driving circuit for a display device so that a low light adjustment is not influenced by a high light adjustment during white balance adjustment. Horizontal blanking period is blanked by a transistor and a clamping potential of a low light level for white balance adjustment is added to the above blanked signal. The signal, to which a clamping potential was added, is gain-adjusted and clamped by a capacitor and a transistor. Next, the clamped portion is blanked at a transistor and the blanked signal is supplied to a CRT through a driving stage. Low light adjustment is done by adjusting clamping potential with a potentiometer and high light adjustment is done by adjusting gain with another potentiometer.

Abstract: The present invention provides an auto white balance adjusting device which can appropriately adjust the white balance. A brightest block searching circuit (8) obtains blocks having block representative values, each R,G,B component of which is greater than a respective predetermined threshold value, and selects the brightest one out of the obtained blocks. A brightest block average value calculating circuit (9) obtains an average of the block representative values distributed in the image signal area of a chromaticity near to that of the brightest block. This brightest block average value is thought to be highly influenced by a predominant light source in taking the picture. The white balance can be appropriately adjusted by using this value, irrespective of the kinds of light sources.

Abstract: Control circuits for the cut-off and drive control of video equipment. A first control device includes a cut-off control circuit and drive control circuit for use in conventional modes. A second control device includes a cut-off control circuit for mode switching and a drive control circuit for mode switching, independent of the first control device. The cut-off and drive adjustments made for every mode switching operation are unnecessary, and the mode switching based on off set data is possible.

Abstract: An automatic white balance adjusting device adjusts the white balance of a white object which is indoors under the influence of bright sunlight, or a white object which is indoors under the influence of dull sunlight light and a fluorescent lamp. The device includes a weighting circuit for a fluorescent lamp block, and a weighting circuit for a sunlight-and-tungsten-lamp block. The former weights an average of the fluorescent lamp block, while the latter weights an average of the sunlight-and-tungsten-lamp block. The weighted averages are used to generate a white balancing signal, which will be used for white balancing a white object.

Abstract: An input signal is input to a detector and a synchronizing frequency of the input signal is detected by a frequency detector. Then, the number of the horizontal lines per vertical period of the input signal is determined according to the synchronizing frequency by a calculator. A control signal for defocusing an electron beam with which a blue fluorescent substance emits light is generated from a defocus controller according to the number of the horizontal lines of the input signal. Here, a range of control signals is previously stored corresponding to a range of numbers of horizontal lines. A focus signal for exactly focusing the electron beam is added to the control signal output from the defocus controller by an adder. Then, the defocus signal is output tom the adder. The defocus signal is amplified by a focus adjusting amplifier 15. The diameter of the electron beam with which the blue fluorescent substance emits the light is controlled according to the amplified defocus signal by a focus adjusting coil.

Abstract: A color temperature selector for a television receiver which can select a color temperature using electrical control signals. The emitter of a drive transistor is fixedly connected to one resistor which is connected in parallel with two selective resistors to change the emitter resistance value. The two selective resistors are selectively connected to the fixed resistor using general semiconductor switches. This arrangement allows a remote controller to select a color temperature by a control signal, and allows to select a desired combination of color temperature setting states.

Abstract: A video camera system for recording an image of an subject. The video camera system includes; a video camera body for recording the image of the subject; a supporting base for supporting a coupling member; the coupling member for coupling the video camera with the supporting base so that the video camera is mounted on the supporting base, and for releasing the video camera from the supporting base; and a controller for setting functions of the video camera, such as the exposure level, the focusing point adjustment mode, the angle of view, the white balance, and the automatic gain control level, to record the image of the subject within a predetermined focal range when the video camera is mounted on the supporting base.

Abstract: White balance control for a video camera is strongly influenced by remarkably change of brightness level, color of an object and photographing conditions. An automatic white balance control device according to the present invention for a video camera can control white balance by controlling timming of outputing control signals for controlling gains of amplifiers for control white balance and changing signal process of a picture image in accordance with a percentage of white color shared in the picture image.

Abstract: The color quality of a received color picture signal is detected by a device for measuring the intensity of at least the red component and the green component of the picture signal. A microprocessor determines a correction value for the white balance correction on the basis of the detected color quality and corresponding to selectable correction values, stored in a memory, for each color component. The method and apparatus permit an application specific correction of the white balance, particularly for use in endoscopic systems, such as video endoscopes and endoscope cameras, to be used in different body organs which cause different color shifts.

Abstract: A white balancing apparatus used for video camera a signal processor for outputting red, green and blue component signals in processing a video signal, an integrator for integrating the output signal of the signal processor, a gate for determining the input video signal whether it is a chromatic signal by using the output signal of the signal processor and for gating the output signal of the signal processor so as to be input to or blocked from the integrator, and a microcomputer for adjusting the gain value of the output signal of the signal processor depending on the output signal of the integrator. Therefore, the white balance performance for the chromatic color components of the photographed object itself is prevented but only the achromatic components are used in performing the white balance, thereby enabling to output cleaner colors.

Abstract: Sixty-four regions are established on an image sensed picture from a video camera, where evaluating value r.sub.ij, b.sub.ij, and y.sub.ij is obtained by averaging color difference signals R-Y and B-Y and luminance signal Y obtained from an image sensing signal for over 1 field period for each region. When the apparatus determines that the difference in the evaluating values between two adjacent regions does not exceed a predetermined value, that is, when that continuing regions have the same color, the weighing amount of the color evaluating values of a corresponding region is adjusted to limit its effect upon the gain control signals used to adjust the gain of the color signal amplifiers. As a result, the effect of objects of the same color towards white balance adjustment is reduced.

Abstract: The disclosed image sensing apparatus includes a first circuit for forming a first signal to control gains of various color signals included in the outputs of an image sensing device in accordance with the levels of the various color signals, a second circuit for forming a second signal to control the gains of the various color signals in accordance with a color temperature of an object to be photographed, and a gain control circuit for controlling and determining the gains of the various color signals by mixing the first and second signals formed by the first and second circuits, in which a high accurate white balance adjustment is effected and the variation of the color temperature of the object is followed.

Abstract: A white balance adjustment apparatus adjusts color component video signals of an aiming subject. The apparatus includes an amplifier for amplifying the color component video signals separately, a color temperature detector for detecting color temperature of the subject and for producing a color temperature signal, a memory for storing the color temperature signal and a selector for selecting either the color temperature signal currently produced by the color temperature detector or the color temperature signal previously stored in the memory.

Abstract: A color printing system includes a central processing unit for generating color image data, a color monitor for displaying color image data generated by the central processing unit and a color temperature sensing device for sensing color temperature of viewing light in which color images displayed on the monitor and color images printed by the printer are viewed. A first light source has a light output intensity controllable by the central processing unit. The central processing unit is adapted to control the intensity of the first light source in accordance with the color temperature sensed by the sensing device so as to match the color temperature sensed by the sensing device to a potential color temperature. Additionally, a second light source may be provided. The second light source has a different color temperature than the first light source and the central processor can adjust the intensity of the first and second light source based on relative color temperatures.

Abstract: In controlling the gain of plural color signals, for the purpose controlling the white balance of a video signal released from an image pickup device and including the above-mentioned plural color signals, there is provided a calculation circuit for calculating color temperature information according to the plural color signals and forming a gain control signal according to the color temperature information, and the variable range of the gain control signal is set at one of mutually non-overlapping plural ranges, whereby the correction error of the white balance is rendered visually inconspicuous.

Abstract: A white balance correction circuit corrects the signal level of red and blue video signals. The circuit includes both active elements and passive elements which cooperate in generating different bias resistances according to a signal level of an input color signal component. The gain of the respective transistor which ultimately amplifies and outputs each of the color signals advantageously can be varied by varying the bias of the transistor according to the signal level of the input color signal. As a result, the circuit minimizes deviation between the gamma characteristics of the red, green and blue video signals. Accordingly, a constant white balance can be maintained irrespective of the signal level of input video signals. The circuitry thus permits excellent reproduction of the original colors on the screen or tube.

Abstract: A white balance adjustment device adapted to be used in contexts where a photographic subject is illuminated with fluorescent lighting. The white balance adjustment device includes an imaging device for forming an image of a photographic subject and for outputting signals representing the image. An adjustment mode selection device is included for selecting a white balance adjustment mode according to the kind of light source used to illuminate the photographic subject. A measurement unit is used to measure color aspects of the light source used to illuminate the photographic subject. White balance adjustment circuitry is included to adjust the white balance of the output of the imaging device in accordance with the adjustment mode selected by the adjustment mode selection device and in accordance with the measured color aspects of the light source used to illuminate the subject.

Abstract: A method of controlling the colour balance of a video signal which comprises green, red and blue channel singals. Pixels are identified which have a green intensity within a peak intensity band. For these pixels, the red and blue intensities are examined to identify pixel subsets which are within respective red and blue peak bands. If the red and or blue peak bands are greater than the green peak band the gain of the red and/or blue channel(s) is increased. If the red and/or blue peak bands are lower than the green peak band, red and/or blue peak bands are determined for the entire video frame and are compared with the green peak band. If the red and/or blue peak bands for the entire frame are lower than that for the green channel, the gain of the red and/or blue channel(s) is increased.

Abstract: A method and circuit for correcting color errors in displaying a color video signal on the display of a color television receiver, the color television receiver having drive circuits for each of the colors red, green and blue, for forming respective color drive signals, in response to color signal components present in the color video signal, for the display, the method including setting up the color drive circuits of the color television receiver for conversion of the color signal components in the color video signal to the color drive signals to a ratio for producing a white color temperature higher than that specified in a television standard, detecting the presence and amount of color in the color video signal to be displayed on the display of the color television receiver, and reducing the color drive signals for at least two of the colors in dependence on the detected amount of color in the color video signal, whereby the resulting chromaticity of the displayed colors is the same as that when the color

Abstract: Sixty-four regions are established on an image sensed picture from a video camera, where evaluating value r.sub.ij, b.sub.ij, and y.sub.ij is obtained by averaging color difference signals R-Y and B-Y and luminance signal Y obtained from an image sensing signal for over 1 field period for each region. When the apparatus determines that the difference in the evaluating values between two adjacent regions do not exceed a predetermined value, that is, when that continuing regions have the same color, the weighing amount of the color evaluating values of a corresponding region is adjusted to limit its effect upon the gain control signals used to adjust the gain of the color signal amplifiers. As a result, the effect of objects of the same color towards white balance adjustment is reduced.

Abstract: A fill-in light emitting apparatus having an illuminating mechanism for emitting illumination light whose color temperature can be varied; a color temperature metering mechanism for measuring the color temperature of the external light; and a color temperature controlling mechanism for varying the color temperature of the illumination light in accordance with color temperature data measured by the color temperature metering mechanism.

Abstract: A white balance adjustment apparatus for adjusting red, green and blue video signals of an aiming subject has amplifiers for amplifying the R, G, B video signals, respectively, a brightness detector for detecting the brightness of the subject, and a mode selector for selecting either an outdoor lighting mode or an indoor lighting mode in accordance with the brightness detected by the brightness detector. A white detector is provided for receiving the R, G, B video signals for each pixel and detecting a pixel with R, G, B video signals that falls in a narrow white range when the outdoor lighting mode is selected, and in a wide white range when the indoor lighting mode is selected. An integrator integrates the number of detected pixels in the white range. A white balance gain control controls the gain of the amplifiers based on the integrated result of the integrator.

Abstract: A chromaticity meter measures chromaticity of light output for each of picture elements selected. Calculated from the measurement is corrective data on each of RGB colors, which in turn used to calculate corrective data on each of RGB at unselected picture elements. In this method, original video signals for each of RGB colors will be correctively modulated based on the thus obtained corrective data. A projected image displaying apparatus is constructed such that adjustment of chromaticity as to white as well as to black from the measurement by the chromaticity meter of chromaticity throughout the entire image, is carried out uniformly and reliably by automatic control using a microcomputer so as to determine optimal condition for correctively modulating the original video signal. This apparatus further includes means for storing the thus obtained optimal condition in a non-volatile memory.

Abstract: Sixty-Four regions are established on an image sensed picture from a video camera, where evaluating value r.sub.ij, b.sub.ij, and y.sub.ij is obtained by averaging color difference signals R-Y and B-Y and luminance signal Y obtained from an image sensing signal for over 1 field period for each region. When the apparatus determines that the difference in the evaluating values between two adjacent regions do not exceed a predetermined value, that is, when that adjacent regions have the same color, the weighing amount of the color evaluating values of a corresponding region is adjusted to limit its effect upon the gain control signals used to adjust the gain of the color signal amplifiers. As a result, the effect of objects of the same color towards white balance adjustment is reduced.

Abstract: An automatic white-balance controlling is for controlling the white-balance of an imaged screen, by controlling the color signal level in accordance with an up-down counting result in a microcomputer. A limited area is established within a VB-VR plane, and a level adjusting operation of the color signals corresponding to the area is limited so as to render a stable white-balance adjusted operation. Judged from data in a time series, the accuracy of the white-balance controlling operation can be assured executing somewhat redundant processing.

Abstract: A picture tube drive apparatus for driving a color picture tube. The picture tube drive apparatus comprises a video output circuit which receives video signals, amplifies them and outputs the amplified video signals, a picture tube drive circuit which receives the video signals amplified by the video output circuit for driving said color picture tube based on video signals, said picture tube drive circuit having means for detecting a beam current corresponding to the brightness of each color flowing through said picture tube, a picture tube connected with said picture tube drive circuit for displaying the video signals, a white balance control circuit into which a detection value of a beam current detected by said picture tube drive circuit is inputted and for outputting video signal level compensation signals for adjusting the white balance of the video image displayed on said picture tube to said picture tube drive circuit.

Abstract: A circuit for controlling white balance in a video signal comprising separators for separating a luminance signal, a red signal and a blue signal from the video signal, gain control amplifiers for amplifying the separated red signal and the separated blue signal, substractors for making a red minus luminance signal and a blue minus luminance signal from the luminance signal, the amplified red signal and the amplified blue signal, integrators for integrating the luminance signal, the red minus luminance signal and the blue minus luminance signal, switching circuit, coupled between the substractors and the integrators, for switching outputs of the substractors to supply the luminance signal, the red minus luminance signal and the blue minus luminance signal having only levels under predetermined levels to the integrators, and microcomputer for determining whether the outputs of the integrators belong to a certain white area, to control gains of said gain cortrol amplifiers when the ouput of the integrators belo

Abstract: A white balance adjuster of a camera comprises a photometering unit for metering a brightness of an object based on a light directed to an image pickup unit of the camera, a color metering unit for metering a color temperature of a periphery of the camera, a plurality of white balance control tables and a selector for selecting one of the white balance control tables in accordance with object brightness information produced by the photometering unit and brightness converted information of the periphery of the camera produced by the color metering unit. A color balance of an output signal of the image pickup unit is adjusted in accordance with the selected white balance control table.

Abstract: A carrier level balancing circuit in which a color aliasing signal occurring when a cameraman takes a picture of an object of an achromatic (black and white) color can be canceled completely. In a carrier level balancing circuit for a color camera formed of a CCD solid state image pickup device of an all pixel separately read out system, two-channel color signals output from the CCD solid state image pickup device are multiplied with independent balance coefficients at every line by multipliers while the balance coefficients are switched in a dot-sequential fashion. Also, values of these balance coefficients are set by a coefficient setting circuit in response to color temperature information. Thus, the carrier levels can be balanced over a range of color temperatures.

Abstract: A luminaire of variable color temperature is arranged for emitting blended color light from luminaire section, with color temperature control signals so transmitted from control section to luminaire-lighting section as to substantially equalize respective differences in reciprocal color temperatures of respective two adjacent stages of the color temperature control signals, to thereby render blended state of emission colors to be variable and a dimming of the blended color light to be realized with the color temperature gradually varied in smooth manner.