Abstract: A solid-state imaging apparatus which effects an electronic shutter operation comprises a solid-state imaging device made up of a plurality of photosensitive pixels arranged in a matrix on a semiconductor substrate, a driving circuit for driving the solid-state imaging device and also controlling the photoelectric conversion time of the photosensitive pixel, a vertical CCD for clipping a first signal obtained during a longer photoelectric conversion time in the solid-state imaging device, at a specified level or above, and then adding the clipped signal to a second signal obtained during a shorter photoelectric conversion time, and a signal processing circuit for amplifying and outputting the added signal, and setting an amplification degree for the second signal to a value larger than an amplification factor for the first signal.

Abstract: A picture in picture (PIP) video signal is applied to a display device via a non-linear processor that is enabled during display of a main picture component and disabled during display of an inset picture component responsive to a PIP identification signal. The non-linear processor is formed in an integrated circuit which includes a pin for connection to a capacitor that stores peak levels of the PIP video signal. The PIP identification signal is subjected to a voltage level translation for varying the pin voltage over a range of values, .DELTA.V, for facilitating ON/OFF operation of the non-linear processor and is applied to a selected plate of the capacitor for varying the pin voltage without substantial alternation of charge stored within the capacitor whereby only a single pin is required for both capacitor storage and on/off control of the non-linear processor and undesirable visual artifacts, such as "trailing contrast bars", are avoided.

Abstract: A contour restoration circuit comprises an input terminal, a plural of delay circuits connected to the input terminal in series, a maximum value detection circuit, a minimum value detection circuit, a mean value calculating the mean value from the maximum and minimum values, a subtractor for subtracting the mean value from the input video signal, a gain controller for the subtracted signal, an adder for adding the gain controlled signal to the input video signal and an output terminal.

Abstract: A color display unit which comprises a plasma display panel and a driving device for driving the plasma display panel so that a picture constituted by input R, G and B signals is displayed on the plasma display panel, wherein the color display unit further comprises a device for analog-to-digital converting the input R, G and B signals and for giving gamma correction to the analog-to-digital converted R, G and B signals, so that the driving device drives the plasma display panel on the basis of the gamma-corrected R, G and B signals, the gamma correction having a characteristic in which a gamma value is made larger than 2.2 in a middle portion of a gamma characteristic curve, and, at the same time, the middle portion of the gamma characteristic curve is shifted to a position having a higher luminance level, and white and black foot portions of the gamma characteristic curve are made smooth.

Abstract: A method for processing multiple color signals representing an image including the steps of obtaining multiple linear color signals representing the image, translating the multiple linear color signals to a linear luminance signal and at least one linear chrominance signal, converting the linear luminance signal to a nonlinear luminance signal and converting the linear chrominance signal to a non-linear chrominance signal by dividing the linear chrominance signal by a non-linear luminarice signal. In addition, an apparatus for processing multiple color signals representing an image including apparatus for obtaining multiple linear color signals representing the image, apparatus for translating the multiple linear color signals to a linear luminance signal and at least one linear chrominance signal, and apparatus for converting the linear luminance signal to a nonlinear luminance signal.

Abstract: In an image pick-up apparatus in which three color signals are gamma-converted and selectively used to generate a luminance signal, a color signal processing apparatus subtracts a linear combination of two color differential signals from the luminance signal to correct the brilliance signal.

Abstract: A non-linear circuit having a transfer characteristic which is adjustable per amplitude segment of an input signal (Yi) includes a segmenting circuit (11 . . . 15, 21 . . . 25) for obtaining a plurality of amplitude segment signals (Y1 . . . Y5) from the input signal (Yi), and a non-linear segment amplifier circuit (31 . . . 35) coupled to the segmenting circuit (11 . . . 15, 21 . . . 25) for separately multiplying segments (Y1 . . . Y5) of the input signal (Yi) by respective segment gain factors (HM1 . . . HM5) in dependence upon a common gain factor (HMa) derived from the segment gain factors (HM1 . . . HM5) and on the basis of the amplitude segment signals (Y1 . . . Y5) for supplying a signal (Y"s) which is adjustable per amplitude segment of the input signal (Yi). The non-linear circuit may also include an output circuit (37, 39) coupled to the non-linear segment amplifier circuit (31 . . .

Abstract: A current source (70) is coupled to supply an output current to a circuit node (60) proportional to a video input signal (R). A first resistor (65), coupled between the circuit node (60) and a source of supply voltage (68), develops an amplified video signal which is coupled from the circuit node to the cathode (K1) of a kinescope (20) via a second resistor (85). A capacitor (100 or 110) is provided having a first electrode coupled to the cathode (K1) of the kinescope (20) and having a second electrode coupled to the circuit node (60) via an amplifier(90). Advantageously, the combined resistance of the two resistors imparts gamma correction to the kinescope, the capacitor and amplifier compensate for stray capacitance associated with the cathode without subjecting low frequency components to any possibility of distortion in the amplifier. Additionally, the capacitance (110) may be varied as a function of the beam current for stabilizing the overall driver amplifier frequency response.

Abstract: There is provided a system and a method thereof for producing enhanced signals from an irreversible compression first processor in which there were performed irreversible compression encoding of signals and subsequently a compression decoding thereof. The method includes defining at least two sets of signals, wherein each set contains signals having a selected property of a signal, feeding the decoded signals of the first processor to a second processor, and processing the decoded signals by the method of projection onto convex sets, thereby imposing conformity to the sets of signals.

Abstract: The white peak level and black peak level of each of three types of color signals R, G and B obtained by picking up a negative image are detected. The amplitudes and levels of the signals are adjusted in such a manner that the white peak levels of the color signals R, G and B coincide as well as the black peak levels of these color signals. Signals representing the detected white peak and black peak levels are superimposed in first-half and second-half portions of a blanking interval of each of the color signals R, G and B. The signals that result can be utilized in subsequent signal processing. Also, the input/output characteristics of a gamma correction circuit are represented by an exponential function, which is for a gamma correction, up to a fixed input range, and by a KNEE curve, whose slope is smaller than that of the exponential curve, in a range beyond the fixed input range.

Abstract: A white balance correction circuit, which receives a luminance signal (-Y) on the input terminal (20) and produces a modified luminance signal, has its gain G1 for the range of small input luminance signal level determined from the resistance ratio of resistors (29, 33), has its gain G2 for the range of medium input luminance signal level determined from the resistance ratio of the resistor 29 and resistors (33, 35) connected in parallel by a transistor (39) that has become conductive, and has its gain G3 for the range of large input luminance signal level determined from the resistance ratio of the resistor 29 and resistors (33, 34, 35) connected in parallel by the transistor (39) and a transistor (38) that has become conductive. Based on this modification, three picture projection tubes (23) have cathode voltage characteristics against the amplitude of luminance signal (-Y) represented by three polygonal lines that approximate the ideal luminance characteristics of the projection tubes.

Abstract: Methods for calibrating a display device, for instance, a computer monitor, that transduces digital inputs to regions of perceived color. The brightness control is calibrated by (1) supplying to the display device digital inputs that produce a black area and an adjacent dark gray area; (2) adjusting the brightness control of the display so that the black area and the gray area are distinguishable; and (3) slowly reducing the brightness control to the point that the black area and the gray area are indistinguishable.

Abstract: So as to make a composing unit (R7, 33) produce a composite signal of a drive voltage for use in producing a driving signal for an LCD having a liminance versus drive voltage characteristic curve approximated by a nonlinear curve generated by a concatenation of at least first through third linear function curves, an analog nonlinear operation circuit (15) comprises first through third amplifier Circuits (31)(1)-31(3)) for generating first through third function voltages in correspondence to the first through the third linear function curves. The amplifier circuits are typically differential amplifiers particularly when the operation circuit is applied to gamma compensation of television video signal for a CRT into a gamma compensated signal which is for the LCD and is produced as the composite signal.

Abstract: A gamma correction circuit includes a plurality of gamma function forming circuits, each of which modifies an input signal to provide different gamma correction signals. The input signal level is compared with a predetermined signal level, and based on the comparison one of the different gamma correction signals is selected as an output signal of the gamma correction circuit.

Abstract: An image capture and display system contains a three-stage digital gamma correction circuit. Three equations are used to determine the gamma correction characteristics for low intensity, medium intensity, and high intensity signal levels, respectively. Linear correction is used for low and high intensity levels, and an adjustable non-linear correction is used for medium levels. The resultant effects of the combined correction characteristics are to increase the effective Signal-to-Noise ratio for low level signals, enhance the gray level differentiation for high level signals, and heighten the contrast control for medium level signals. In addition, the contrast control is effective throughout the entire range of signal intensity levels. The image capture and display system provides a high quality visual display, with a simple, economical hardware implementation of the inventive gamma correction circuit.

Abstract: Apparatus that implements a nonlinear transfer function (gain) that provides for gamma correction of nonlinear image projectors. The nonlinearity of the transfer function is designed to compensate for the nonlinearity of a nonlinear light modulator, such as a liquid crystal light valve and cathode ray tube combination, for example, that is used in the image projector. The gamma correction circuit comprises a plurality of amplifiers that include current sources coupled together to sum their output currents, and each amplifier is adapted to implement a predetermined transfer function, and provide differing levels of current. An optional output resistor may be employed to convert the composite output current into a corresponding output voltage. Each of the plurality of amplifiers typically comprises first and second emitter coupled pair transistors plus their associated current sources. The present invention corrects the grey scale linearity of the image projector in which it is employed.

Abstract: A video input signal is amplified and applied to the cathode of a kinescope via linear kinescope driver amplifier provided with an output impedance sufficiently high to impart gamma correction to images displayed by the kinescope but tending to diminish the bandwidth of the amplified video signal applied to the cathode. A capacitor is included in the driver for restoring the bandwidth of the amplified video signal. For stabilizing the high frequency response (detail) of displayed images the value of the capacitor is varied as a function of the brightness of displayed images.

Abstract: An image processing apparatus is disclosed which includes circuitry for selectively applying variable gamma corrections to an image signal during both on-line and off-line modes of operation. In the off-line mode, the apparatus operates to simultaneously correct image signals for non-linearities produced by both an input device and an output device. In the on-line mode, correction is made for the non-linearities of the input device and a separate correction is made for the non-linearities of the output device. Such operation allows the apparatus to process linear data in the on-line mode.

Abstract: A video signal to be processed is applied to a non-linear processor having an adjustable gain responsive to a control signal over at least one portion of the amplitude range of the video input signal. A sampling circuit, responsive to the video signal, generates video samples related to the video signal. A control circuit, responsive to the video samples, generates the control signal in accordance with the number of samples in at least a given amplitude range thereby controlling the percentage of samples of a given range in displayed images. Plural control and sampling circuits may be included provide control for white stretch processing, black stretch processing and video mid-point processing for enhancing contrast through out the entire video signal range.

Abstract: Gamma correction is performed by dividing the total gamma transfer function input value range into a plurality of segments. The source RGB data is then mapped into an associated x-position in a "standard" segment, and gamma correction is performed on the mapped value as if it was initially in that standard segment. The resulting corrected value is then de-mapped back into the original input value segment. Only the portion of the gamma correction curve which is within the "standard" segment is processable by the circuitry. The segments into which the input value range is divided may occupy ratiometrically increasing portions of the input value range, with the high-order half of the range designated as the standard segment. The lowest-order portion may be approximated linearly. Mapping into the standard segment then involves shifting the input value to the left until the highest order logic 1 is in the highest order bit position.

Abstract: An apparatus and method for processing signals of an imaging device comprising a detection circuit for detecting the color temperature of a light source for illuminating an object of which the image is picked up and a circuit for varying .gamma. correction characteristics for chrominance signals, whereby the .gamma. correction characteristics are changed to reduce the gains for low level regions of input signals to .gamma. correction circuits in accordance with the color temperature, thereby enabling the final quantize noise to be reduced.

Abstract: A contrast correction device for correcting a contrast of an image formed by video signals includes a brightness/darkness detecting circuit for detecting a tone level of the image and for producing a bright signal when the tone level is greater than a predetermined brightness, and a dark signal when the tone level is less than a predetermined darkness. A correction circuit is provided for correcting a luminance signal by a negative gamma correction in response to the bright signal, and a positive gamma correction in response to the dark signal. Thus, the contrast of bright areas in the image are enhanced when the bright signal is produced, and the contrast of bright areas in the image are suppressed when the dark signal is produced.

Abstract: A video signal processing circuit of a CCD-type color video camera includes a gamma-correcting circuit section, a delay circuit section, a chrominance signal processor and a luminance signal processor. Accordingly, the circuit is configured such that gamma-compensation processing is performed before the separation of the luminance and chrominance signals, and a DC fluctuation due to the gamma-compensation processing is compensated in the luminance signal processor. Thus, horizontal noise caused by the gamma correction can be eliminated, which not only improves picture quality but also enables a reduction in chip size.

Abstract: A nonlinear processing apparatus in which a common input signal is input to multiple amplifiers having mutually different amplification factors and different offset voltages and a non-adder/mixer selectively outputs the output of each amplifier selected for each level region of the input signal, thereby providing a final nonlinear output. It is therefore possible to independently set and adjust the output characteristic for each amplifier (the frequency response and offset voltage in the case where this invention is applied to a gamma compensator), thereby ensuring highly-accurate setting and adjustment of the output characteristic over the entire output level range.

Abstract: A video signal processing circuit includes a level shifter for shifting the dc level of an input luminance signal; a gain adjuster for increasing the gain for the luminance signal when the luminance signal has a low luminance level and for decreasing the gain for the luminance signal when the luminance signal has a high luminance level; and a shifting amount setting unit for setting the amount for shifting the dc level on the basis of the frequency distribution of the luminance signal and the rate of modulation of the luminance signal.

Abstract: The present invention relates to a noise reduction and signal compensating circuit for video imager which compensates a received picture image of a high density television or general television and permits reception of a clean image without noise, and reduces the deterioration in quality of a reproduced picture image which is attributed to a variable reproduction speed in a video cassette recorder (or video disk player).Accordingly, this invention provides an automatic picture quality compensating circuit which has an automatic picture quality compensating means to create a clean picture image by improving sharpness and removing noise components contained in the picture image.

Abstract: A gradation corrector for use in a television receiver which can subject a signal at any luminance level to non-linear correction to provide optimum image quality. Memory stores therein luminance histogram of an input signal. On the basis of the data, a circuit detects a total frequency, a circuit detects luminance distribution, and a circuit detects the expanse of the luminance distribution. A circuit calculates a fixed value to be added. Further, a circuit detects a minimum luminance level, and a circuit detects an average luminance level. A circuit calculates an accumulation starting point and a circuit calculates an accumulation stopping point. An adder adds the calculated fixed value to the data in the memory. A circuit accumulates the results in the range from the accumulation starting point to the accumulation stopping point. The accumulation result is stored in memory.