Abstract: A low pass filter smooths a voltage corresponding to a least significant bit of a digital image signal outputted from an A/D convertor, and outputs the smoothed voltage to a sample-and-hold circuit. In the sample-and-hold circuit, a sample-hold-pulse is added during an optical black period, so that a voltage of the least significant bit of only a black level is extracted and outputted to a clamp level adjusting circuit. In the clamp level adjusting circuit, when the voltage inputted from the sample-and-hold circuit is higher 0 volts, a voltage, corresponding to a standard voltage from which the inputted voltage is subtracted by a differential amplifier, is outputted to a clamp circuit, and when the inputted voltage is 0 volts, the clamp voltage is pulled up by a pull-up resistance.

Abstract: A contrast correcting circuit for preventing white distortion in a dark screen comprises: an integrator for integrating brightness levels of video signals, and for calculating a sum of the brightness levels; a ROM for storing different types of table data exhibiting contrast conversion characteristics according to the brightness; a selection signal generator for setting as a reference value the sum of the brightness levels of all of the pixels when the brightness levels are at a maximum, for comparing the reference value with an integration output of the integrator, and for instructing the ROM to selectively output table data suitable for the brightness of a screen selected from the different types of table data; and a RAM for storing a conversion table for correcting the contrasts of the video signals by means of the table data.

Abstract: An imaging system for achieving enhanced image detail includes a sensor subsystem, an electronic image processing subsystem, and an automatic gain control (AGC) unit. The sensor unit is operative for sensing an image received from an exterior environment and for converting the image to an electrical representation having a peak value that is related to the dynamic range of the image. The electrical representation is then processed in the electronic image processing subsystem using a unique multiple order, non-linear transfer function that processes the signal in a manner that is dependent upon the dynamic range of the input image. The output signal of the electronic image processing subsystem is then applied to the AGC unit which performs a conventional AGC function on the signal. Thus, the imaging system automatically adjusts to changing scene content in the input image in a dynamic manner.

Abstract: In a multi-window arrangement, the light output attributable to each window in a multiple window display is calculated, for example, in accordance with the video signal that provides the picture information for display in the window and in accordance with the window area. When the total light output contributed by all the windows exceeds a predetermined level, a loop controller automatically reduces, for example, the contrast and the brightness in selected windows, in accordance with a rule, in a loop control manner. The result is that the total light output drops below the predetermined level.

Abstract: An electro-optical device and a method for displaying an image are disclosed. A clear image with a clear profile can be displayed therein by processing input image data, for example input image data of TV broadcasting received by the device.

Abstract: An automatic beam limiter circuit (ABL circuit) calculating an average of a video signal at least a portion of the video signal is provided. After a converter circuit converts an analog signal, which is generated from the video signal, to a digital signal, a horizontal and a vertical average circuits calculate a horizontal and vertical averages of the digital signal at least a portion of the digital signal. The portion of the digital signal is a scanned line of the digital signal on a CRT. A comparison circuit compares a first calculation value calculated between a reference value and the vertical average with a second calculation value calculated between the reference value and the horizontal average, and outputs a first comparison signal and a second comparison signal based on the comparison results. A gain control circuit produces a gain control signal for adjusting the brightness/contrast in response to the first comparison and second comparison signals.

Abstract: The present invention discloses a contrast control method and circuitry for setting and compensating the contrast of a liquid crystal display (LCD). The present invention has circuitry for generating a contrast voltage normally applied to a control pin. Normally the actual contrast of the LCD is a sensitive function of the difference between the applied contrast voltage and the display power supply voltage. The present invention generates a reference voltage that is adjustable and made to vary inversely with temperature. The contrast control circuitry uses a feedback loop to make the difference voltage between the display power supply voltage and the contrast voltage equal to twice the reference voltage. A contrast setting made using the circuitry of the present invention now becomes independent of the display power supply voltage and compensated for variations in the temperature of the LCD. A high gain amplification method for reducing error voltages and providing wide dynamic range is also disclosed.

Abstract: An apparatus and method for controlling contrast for a liquid crystal display (“LCD”), especially active-matrix LCDs, while receiving large dynamic range video data to be displayed to the user by the LCD. Contrast settings of the LCD correspond to a single look-up table from a set of different and multiple look-up tables rather than using the contrast setting of the LCD to select different voltage values from a single look-up table. The values of the reference voltages of the LCD are varied so that all shades of gray are available with each contrast selection resulting in a high image quality and a high contrast.

Abstract: A procamp to color transforms component digital video data. The procamp includes a digital multiplier coupled to receive component digital video data corresponding to at least two different pixel parameters. The digital multiplier is configured to selectively multiply the component video data for different pixel parameters by different factors.

Abstract: A process for color adjustment of a color monitor including a cathode-ray tube and a brightness adjustment module includes providing a nominal brightness signal downstream of a white level adjustment module for adjusting a white level and upstream of a black level adjustment module for adjusting a black level. The process also includes setting a voltage required to obtain a black color image, setting a voltage required to obtain a white color image, providing the nominal brightness signal upstream of the white level adjustment module, and setting the voltage required to obtain the black color image.

Abstract: An automatic brightness correction apparatus for automatically correcting the brightness property of the image display device is configured to insert a test pulse at a predetermined level within a level range including an intermediate level to the video signal and displays the image of the test pulse on the video image display device, detect a deviation of the brightness of the image of the test pulse displayed on the video image display device from a benchmark, and correct the level of the video signal based on the detected deviation.

Abstract: A video processing method comprises the steps of dividing an entire input data region into three of first, second and third regions in order from the low level side thereof; setting, as an output data characteristic to input data, a trapezoidal characteristic which is nonlinear and continuous as a whole and consists of a linear portion in the first region where the gain is greater than one, a linear portion in the second region where the gain is equal to one exactly or approximately, and a linear portion in the third region where the gain is smaller than one; setting, as another output data characteristic to the input data, an S-shaped characteristic which is nonlinear and continuous as a whole and consists of linear portions in the first and third regions where the gain is smaller than one, and a linear portion in the second region where the gain is greater than one; selecting either the trapezoidal characteristic or the S-shaped characteristic; and correcting the digital luminance data in accordance with th

Abstract: A flat-panel display device changes the level of a video signal supplied from a video signal source in the horizontal blanking period on the basis of a selected voltage value from a voltage generation circuit, and this voltage is sampled in response to a sampling clock from a timing generation circuit and is latched by a signal line driving circuit. The latched signal is supplied to a flat display panel along with a scanning signal from a scanning line driving circuit to display an image according to the aspect ratio of the flat display panel.

Abstract: A video signal processing apparatus is provided that includes a gate pulse generator and a luminance signal processing unit. The gate pulse generator detects a high frequency band in accordance with a luminance signal separated from a composite video signal and outputs a gate pulse signal. The luminance signal processing unit adjusts a contrast with regard to a high frequency band in the luminance signal in accordance with the gate pulse signal received from the gate pulse generator. The high frequency band having a large black/white comparison is detected in the apparatus from the luminance signal, and a contrast processing with regard to the luminance signal is decreased in the detected high frequency band. Thus, the video signal processing apparatus can reduce or eliminate a picture flickering in the radio frequency band.

Abstract: A method and apparatus for dynamic contrast improvement in video pictures. There is a strong demand for picture contrast but each video display has a limited dynamic range. The picture contrast can't be increased by simply increasing the video signal amplitude because exceeding the display dynamic range in some video scenes causes unwanted disturbing effects. According to the present invention the video pictures are analysed framewise in real time and the parameters of a transfer function for contrast improvement are adjusted depending on the analysis results for the best subjective picture quality.

Abstract: The present invention relates to an automatic gain control circuit in which the automatic gain control function is performed entirely in the digital domain. In an illustrative embodiment, the digital automatic gain control circuit for an image sensor having associated therewith an analog-to digital (A/D) converter for converting analog electrical signals from the image sensor to corresponding digital codes, includes a min/max detector for determining minimum and maximum electrical signal values from the digital codes of the A/D converter for each frame of image. A filter coupled to the min/max detector dampens instantaneous changes of the minimum and maximum values by filtering to provide filtered minimum and maximum values.

Abstract: Recent circuit concepts inject measurement lines, for cutoff and drive control of the cathode current, into each color channel during the vertical frame blanking period. Owing to the physically dependent exponential beam current characteristic profile as a function of the cathode control voltage VK, the exponent &ggr; of the characteristic profile and the ratio of two cathode components IK1 and IK2 may be used to form control reference values for cutoff and drive control, this process being started in each case from a fixed value of the exponent &ggr; or of the ratio of the two cathode currents IK1 and Ik2. However, it has been found that, if a fixed value is assumed for the exponent &ggr; or for the ratio of the two cathode currents IK1 and IK2, it is not possible to achieve an optimum result for displaying monochrome pictures. Thus, according to the invention, the exponent &ggr; is defined as a function of the color tube 1. The aim in this case is to reduce a &ggr;-dependent DC voltage offset u0f to zero.

Abstract: In an image signal input apparatus that performs high-speed input processing of an image signal and, in particular, a brightness signal, a video signal is processed by a clamping circuit so as to achieve a constant reference level, and then input to an A/D converter. The A/D converter samples the video signal synchronously with a clock signal of a frequency 4fsc. The output of the A/D converter is input to a selector directly or via a 4-data arithmetic mean circuit. The 4-data arithmetic mean circuit obtains an arithmetic mean of every four consecutive data output from the A/D converter. The obtained 4-data arithmetic mean data correspond to the brightness signal. After the 4-data arithmetic mean data is stored in a memory through a DMA controller, the data is output to a personal computer via a Centronics® interface, thereby reducing the amount of data memory necessary for input processing to a quarter of the normal amount.

Abstract: A video input level control circuit in a video display device which can improve picture quality of the video appliance by selectively controlling input levels of the video signals inputted in different manners from different-typed video cards of a PC so that the input levels may be minimal.

Abstract: A method and apparatus are provided to allow threshold values needed for the desired number of gradations to be set through a simple process when converting image data with numerous values into a low number of gradations. The desired number of gradations is achieved without shading being noticeable even for images having shading. The cumulative frequency distribution of the pixels for each brightness is determined from image data having a brightness range with designated gradations. The average brightness and standard deviation of the portion that is primarily background is determined from this cumulative frequency distribution. The first threshold value is determined on the basis of this average brightness and standard deviation, the second through n-1st threshold values corresponding to the meaningful information are determined on the basis of this first threshold value. An n value conversion process is accomplished using these threshold values.

Abstract: A method and apparatus for controlling contrast of images when displayed on a monitor begins when signals corresponding to an image and a contrast feedback signal are received. The signals are mixed with the contrast feedback signal to produce image output signals. The contrast feedback signal is, in turn, determined based on the contrast level of the image output signals. As such, a closed loop feedback circuit is provided to control the contrast levels of the image output signals.

Abstract: An apparatus for automatically stabilizing the black level of a displayed picture when (1) an automatic black level stabilizing function is OFF, (2) black level error occurs between at an ON state and at an OFF state and (3) black level variation and picture disturbance occurs during activation and deactivation of the automatic black level stabilizer. Black level variations when the automatic black level stabilizer are OFF is controlled by processing a cathode current in a negative feedback loop and controlling a CRT grid voltage, storing a divided grid voltage during a converging period and processing the grid voltage in another negative feedback loop in order to adjust the grid voltage to an ON state value.

Abstract: An image enhancing method using a mean-separate histogram equalization method is disclosed. An input image signal is divided into two sub-images in a picture unit according to a mean level of the input image signal. Then, cumulative density functions for each of the sub-images are calculated. Afterwards, the input sample is mapped into two gray levels, each of which belongs to a first range and a second range, by using first and second transform functions defined by use of the cumulative density functions, respectively. Finally, one of two mapped levels is selected depending on the magnitude of the input sample. As a result, the brightness of the given image can be preserved while the contrast is enhanced.

Abstract: A method and apparatus are provided to allow threshold values needed for the desired number of gradations to be set through a simple process when converting image data with numerous values into a low number of gradations. The desired number of gradations is achieved without shading being noticeable even for images having shading. The cumulative frequency distribution of the pixels for each brightness is determined from image data having a brightness range with designated gradations. The average brightness and standard deviation of the portion that is primarily background is determined from this cumulative frequency distribution. The first threshold value is determined on the basis of this average brightness and standard deviation, the second through n- 1st threshold values corresponding to the meaningful information are determined on the basis of this first threshold value. An n value conversion process is accomplished using these threshold values.

Abstract: A black level detecting circuit compares an input video signal with a current minimum value of input video signals, then detects a difference between the input signal and the current minimum value when the input value is smaller than the current minimum value, and then outputs the detected difference only during a detecting period of the black level, then corrects the minimum value by using this output for renewing the current minimum value, and finally outputs this renewed minimum value as a new minimum value of the input video signal. The black level detecting circuit also latches the minimum value during the vertical blanking pulse and initializes the minimum value during a vertical blanking period so as to detect a black level of the input signal.

Abstract: In a television receiver, shading correction is carried out without deteriorating the S/N ratio. In a television receiver including a CRT, and a shading corrector for supplying an image signal to a cathode of the CRT (cathode-ray tube) and for correcting brightness inequalities of an image formed on a fluorescent screen by way of electron beams which are increased/decreased in response to a change in the potentials applied to a first grid of the CRT, the shading corrector supplies a shading correction signal to the first grid.

Abstract: A circuit and method for optimizing the display of a video signal on a display. Control of the display's brightness and contrast is based on aspects of a video signal, such as the average amplitude of the signal and the standard deviation. These aspects of the video signal are determined and the video signal manipulated based on the determined characteristics such that the resultant video signal is optimized to the dynamic range of the display.

Abstract: Average picture levels of a first video signal (for example, a parent picture signal) and a second video signal (for example, a child picture signal) are detected at first and second APL detection circuits, respectively. A compensation voltage sharing circuit inputs a compensation voltage, for example an ABL/ACL compensation voltage, and shares the compensation voltage according to a ratio of the APL values detected at the first and the second APL detection circuits. The shared compensation voltages are added to the first and the second video signals at the first and the second video processing circuits, respectively. The processed video signals are synthesized at a synthesizing circuit and the synthesized video signal is displayed on a screen of a display device as a multipicture, in which the first and the second pictures are independently and properly compensated by the ABL/ACL function. Thus, a good quality multipicture can be seen.

Abstract: A video signal luminance control apparatus is provided, which includes an input portion for receiving a luminance signal of the video signal, a transistor with a collector receiving the input luminance signal input from the input portion, via a resistor, and a controller which is connected to the base of the transistor for outputting a control signal for controlling the on/off operation of the transistor in an area where an on-screen-display (OSD) character is displayed. A simple transistor receiving the control signal is used to control the luminance of a video signal in an area where an OSD character is displayed, thereby providing a luminance control apparatus for clearly displaying OSD characters.

Abstract: A visual image signal processing apparatus includes: an overlaying unit for overlaying a brightness reference signal at a predetermined position in a fly-back period of an input visual image signal; a first clamping unit for clamping an output from the overlaying unit at a predetermined clamping voltage; a detecting unit for applying an output from the first clamping unit to a driving electrode of a cathode ray tube and for detecting a beam current flowing based on the brightness reference signal overlaid in the input visual image signal; and a second clamping unit for controlling the predetermined clamp voltage based on the beam current detected by the detecting unit.

Abstract: An apparatus and a method for contrast adjustment are provided which require a reduced amount of information for the contrast adjustment. A preliminary adjustment factor is first calculated on the basis of a contrast adjustment factor, and then input image data is processed on the basis of these two adjustment factors to provide contrast-adjusted image data. For example, the inclination of a contrast adjustment line is defined by the contrast adjustment factor, and a shift amount (intercept) of the contrast adjustment line is defined by the preliminary adjustment factor which is properly determined in correspondence with the contrast adjustment factor. Thus, not only the contrast of an image but also the density of the overall image can be properly adjusted simply by specifying a single adjustment factor.

Abstract: A method for enhancing the contrast of an interlaced video input including a series of input video cycles, each input video cycle having a plurality of input fields, one field in each cycle being a bright field, the method including detecting at least some of the bright fields and constructing a contrast enhanced, dynamic, video output image based on the detected bright fields. Preferably, the contrast enhanced, dynamic, video image includes a series of output video sequences, each output video sequence having a plurality of output fields corresponding to one of the detected bright fields.

Abstract: The direct current voltage level and amplification of a multiple channel output imaging element are adjusted by comparing the output values of each channel. A calculating device, such as, for example, a CPU uses the data of one channel (i.e., a standard channel), which was sampled by a sampling circuit, as a standard, and then takes the difference between this data and the data of the other channels to calculate the offset and amplification differences. The results are sent to a D/A unit, which sends regulating voltages to offset regulating circuits and to amplifying circuits. In this manner, the offsets and amplifications of each channel are adjusted so as to become equal.

Abstract: A control apparatus adapted to adjust the image screen display characteristics of a video monitor. The apparatus comprises a microprocessor, an encoder, and a rotary input signal processor. The microprocessor implements operation and adjustment control of the monitor. The encoder provides a rotary knob that a user of the monitor device may rotate in either direction for generating a pair of pulse signals. The rotary input signal processor is coupled between the microprocessor and the encoder for receiving the pair of pulse signals generated by the encoder and reshaping the pulses for input to the microprocessor. The microprocessor receives the reshaped pulse signals to determine the direction of rotation and the range of rotation of the encoder. The determined direction and speed of rotation are utilized as the basis for the adjustment of the image screen of the video monitor device.

Abstract: The object of the present invention is to easily compensate automatic brightness limiting performance and automatic contrast limiting performance even if a picture is displayed with a different aspect ratio and to prevent deterioration of picture quality such as gradation and sharpness.

Abstract: A device for filtering video images, of the type which includes first and second circuit portions, each having first and second input terminals respectively adapted to receive digitalized luminance and chrominance components of a television signal, and an output terminal coinciding with an output terminal of the device. The first and second circuit portions further include first, second and third filters, cascade coupled to one another, and a fourth filter, respectively.The first, second and third filters incorporate a computational circuit which uses a logic of the fuzzy type to process the digitalized luminance component. The fourth filter includes a computational circuit which processes the digitalized chrominance components based upon a parameter supplied from the second filter.

Abstract: The invention is subjected for a television receiver which is capable of simultaneously displaying a picture signal by at least first and second picture images on a cathode ray tube and including means for generating the first and second picture signal, a superimposer for selectively supplying the first and second picture signal to the cathode ray tube, an APL detector for receiving the first and second picture signals to detect respective average picture levels of the first and second picture signals respectively thus producing first and second level detection signals, an ABL detector for generating a detection voltage responsive to a variation in an anode current of the cathode ray tube, and control means for controlling at least one of contrasts and brightnesses of the first end second picture signals by commonly operating on the first and second picture signals in response to the detection voltage from the ABL detector as well as for independently controlling at least one of contrasts and brightnesses of

Abstract: The invention is provided to automatically track the color regardless of the adjustment of the brightness level of a display device. The method provided comprises the first step of calculating a bias voltage, Rb, Gb, Bb, for the Red, Green and Blue cathode respectively, responsive to a brightness voltage applied to the control grid terminal, such that the condition of (Rb-G):(Gb-G):(Bb-G)=(Rbmin-Gmin):(Gbmin-Gmin):(Bbmin-Gmin) holds. The second step of the invention is to output the Rb, Gb, Bb obtained in the first step to each bias voltage input terminal of the video control circuit for the Red, Green and Blue cathode respectively, such that the color of the display device is independent from the change of the brightness value G.

Abstract: Systems and methods for improving the intensity equalization of image data obtained with systems that perceive images with energy sources other than visible light includes a sensor for such data; a converter for transforming the image data from analog form to digital form; a converter for transforming the digital data into black-and-white images containing a predetermined, desired number of gray shades; an intensity equalizer that compensates for the logarithmic effect of visual images on a human eye; an intensity equalizer that compensates for the non-linear effect of the display device for the data; and a converter for transforming the digital intensity-equalized black-and-white image data into analog form for display on a device such as a conventional CRT.

Abstract: A configurable video output channel architecture includes a plurality of parallel video pipelines arranged to drive a video display; a device for selecting an output of one of the video pipelines and generating a readback signal representative thereof; and a device for adjusting a display specification of at least one of the video pipelines using the readback signal. The display specification adjusted may include the maximum video level, the blanking level, and the sync level of the video waveform. The adjusting device may also adjust the characteristic impedance of each pipeline. The selecting device includes a multiplexer and an analog to digital converter, and the adjusting device includes a controller which monitors the readback signal and generates a control signal to adjust the display specification if the readback signal is outside of a desired range.

Abstract: A display apparatus includes manual keys provided to supply color temperature coefficients to contrast and brightness control units, so that an adjusted ratio of the color temperature coefficients is generated independently of contrast and brightness control signals. Consequently, a color temperature which is once determined, is maintained, even if contrast and brightness are changed.

Abstract: A television receiver includes a first signal processing unit that generates contrast controlled first R, G and B signals and a second signal processing unit that outputs second on-screen R, G and B signals. A switching unit receives the first and second R, G and B signals and selectively outputs one of them to a color CRT. An ABL voltage, which changes in response to a level of video displayed on the CRT, is provided to the first and the second R, G and B signals. A control unit determines whether to execute the contrast control of the second R, G and B signals based on a ratio of video corresponding to the second R, G and B signals out of the total video displayed on the color CRT.

Abstract: Automatic brightness control apparatus for a monitor which can provide a high picture quality by properly adjusting the back raster's brightness in accordance with the picture's brightness produced on a screen. According to the apparatus, the back raster's brightness is lowered in a relatively bright picture state, while it is heightened in a relatively dark picture state.

Abstract: A high frame rate camera includes;a multi-channel sensor array for producing a plurality of parallel analog image signals representative of a sensed image;a plurality of analog-to-digital converters (ADC) for converting each of the parallel analog image signals to parallel digital image signals, wherein each of the ADCs has a fine gain parameter which is a function of a top ladder potential and also has a fine offset parameter which is a function of a bottom ladder potential; anda control for controlling the fine gain and offset parameters of each of the ADCs by means of fine gain and offset control signals which are a function of desired average output black and gray levels of the image signal.

Abstract: The present invention relates to an image enhancement circuit which adaptively controls the brightness and contrast of a video input signal according to its average brightness level. The circuit calculates the average brightness level during a predetermined period with respect to a video signal to be input through an input terminal and controls the brightness and contrast of the video input signal according to brightness correction characteristics corresponding to the calculated average brightness level, in which the range of the average brightness level in the video input signal is divided into a plurality of areas, and a plurality of input-output characteristic curves are provided so that the brightness and contrast of the video input signal is differently corrected for respective areas.

Abstract: In an ultrasonic microscope apparatus, an ultrasonic pulse transmitter-receiver emits an ultrasonic wave irradiated on a sample, receives an echo from the sample, and emits an electric output signal in accordance with the received echo. A scanner is provided for scanning the sample by relatively moving the ultrasonic pulse transmitter/receiver and the sample, and, a detection circuit is provided for detecting an echo component included in the output signal from the ultrasonic pulse transmitter-receiver and for emitting a detected signal. A picture quality adjuster receives the detected signal, adjusts brightness and contrast of the detected signal, and outputs the adjusted signal as an image signal. An adjustment controller adjusts the adjustment amount of brightness and contrast in the picture quality adjuster in accordance with the brightness and contrast values of the image signal output from the picture quality adjuster.

Abstract: A video signal processor for controlling a displayed image on a CRT having a cathode electrode and a grid electrode includes a generator for generating a brightness reference signal, an adder for adding the brightness reference signal to a black level in a blanking period of an input video signal. The added brightness reference signal is applied to the cathode electrode though a current detector for detecting a current of the added brightness reference signal. A current level signal produced from the current detector is used for determining and clamping the peak of a control voltage applied to the grid electrode such that a voltage difference between a peak of the added brightness reference signal and the peak of the control voltage is maintained constant.

Abstract: In a DAC-output circuit of a TV set, an output judging part lowers a multiplying factor of sub-data as user data come close to zero, to converge the output onto zero in accordance with the turning down of the user data.

Abstract: A pedestal clamping device clamps a pedestal level of an input video signal in response to a predetermined pedestal voltage, and converts the input video signal into a clamped video signal. A black-level expanding device expands a tone of a black portion of the clamped video signal, and converts the clamped video signal into a black-level expanded video signal. A color greatest detecting device detects a greatest of color signals of the input video signal. A adding device adds an output signal from the color greatest detecting device and the pedestal voltage.

Abstract: A circuit arrangement for processing an input video signal (V) is described, which video signal has a fixed black level (SP), a given white peak value (WW) as well as a black peak value (SW) dependent on the picture contents (during tb), in which a correct display of the blackest and brightest parts of the picture contents of the video signal (V) is rendered possible without many components and without interference.