Abstract: In the &ggr; correction circuit, a crossover point arithmetic processing unit performs arithmetic processing for each region on crossover points y in the output data direction of a &ggr; correction crossover line based on a plurality of slope data A respectively specified for each of a plurality of regions and crossover point positions X in the input data direction set in advance.

Abstract: A video signal processing circuit in which nearly 100% of a largest possible dynamic range can be used, desired contrast is obtained, and desired brightness characteristics are obtained by an increasing in luminance of a screen. The circuit has an RGB amplifier which amplifies three primary color video signals R, G, and B by a predetermined gain and in which the gain is controlled by a gain control signal, A/D converters for converting analog three primary color video signals which are generated from the RGB amplifier into digital signals respectively, inverse gamma correcting circuits for effecting an inverse gamma correction to the three primary color digital video signals respectively, an OR circuit and a peak holding circuit for detecting peak levels of the analog three primary color signals, and a gain control signal generator for generating a gain control signal in accordance with the peak levels.

Abstract: A current frame portion (21) stores therein the most recent information of an image of those fingerprint images input from an inputted unit (1), while a previous frame portion (22) stores therein image information saved in the current frame portion (21). A pixel comparing portion (31) compares mutually corresponding pixel gray-level value information saved in the current frame portion (21) and the previous frame portion (22) respectively. A gray-level-value-changed pixels counting portion (32) counts the gray-level-value-increased pixels and the gray-level-value-decreased pixels based on the resultant information of that comparison of the pixel gray-level values. A pick-up timing deciding portion (33) utilizes the results obtained by the gray-level-value-changed pixels counting portion (32), to automatically detect a fingerprint image appropriate for matching in order to thus decide pick-up timing and also in order to output to an output unit (4) an appropriate fingerprint image based on the decision results.

Abstract: An apparatus and a method for compensating the gray-scale values of an image scanned by a contact image sensor. The gray-scale compensating apparatus includes: a power supply for providing a fixed level of voltage source, a contact image sensor for scanning an image and outputting image voltages VIMG of pixels of the image, or scanning a white pixel and outputting the white-level voltage VP of the white pixel, an analog/digital converter, to receive the fixed voltage from the power supply and the image voltage VIMG or the white-level voltage VP, a microprocessor to calculate the average of n white-level values G(x, y), where n is an integer, and the average value G′(x)=(G(x, 0)+G(x, 1)+ . . . +G(x, n−1))/n. The microprocessor also determines the gray-scale values g′(x, y) of the image being compensated by calculating the gray-scale values g(x, y) of the image not compensated in accordance with the value of G′(x).

Abstract: A method and device for producing an accurate approximation of a digital input word translated by a monotonic transfer function. The digital word is translated into a non-monotonic output word comprised of a closest-approximation component and an error component. The error component is zero for regions in which each consecutive input word produces a unique closest-approximation component. In regions in which each consecutive input word produces the same closest-approximation component, the error signal represents the number of consecutive input words which produce the same closest-approximation component, and the position within that run of consecutive input words occupied by the present input word.

Abstract: Aiming to improve color reproducibility of a red part having high color saturation, a gamma compensation apparatus of the present invention is composed of a bending point setting block 100a and a gamma compensation block 101a and bending point setting block 100a is composed of a high APL detection circuit 1a inputting an average picture level of an input luminance signal and for detecting and taking out a signal component higher than a designated level; a gain controller 2a for gain controlling the detected signal at the high APL picture detection circuit; and an adder 3a for adding a designated offset to the output of gain controller 2a, and gamma compensation block 101a is composed of a slice circuit 4a inputting a color difference signal (R-Y) and the output of bending point setting block 100a and taking out a color difference signal component higher than the output signal level of bending point setting block 100a; a gain controller 5a for adjusting the output level of slice circuit 4a; and a subtracter 6a

Abstract: A non-linear response correction apparatus and method reduce look up table size and output error. In one embodiment, a range of an N-bit input signal is split into two or more sectors, based on a gradient of a non-linear correction curve and an allowable error, and then a N-bit input signal is divided into U upper bits and D lower bits where U and D depend on which sector contains the input signal. First and second look up tables read first and second data stored therein, respectively, using the upper bits of the digital signal as an address. The first data is the difference between a corrected signal and the input signal, and the second data is the gradient of the corrected signal with respect to the gradient of the input signal. The second data read from the second look up table is multiplied by the lower bits, and the first data read from the first look up table is added to the upper bits.

Abstract: A camera includes an exposure part arranged to cause a film loaded on the camera to be exposed to light, an image sensor arranged to convert an object image into an electrical signal, a signal processing circuit arranged to carry out predetermined processes on the signal outputted from the image sensor, the signal processing circuit being arranged to perform the processes for obtaining an object image which is nearly equivalent to an image of a picture to be obtained when a specific film is exposed to light under set exposure conditions, and a display device arranged to display the object image by using the signal processed by the signal processing circuit.

Abstract: Fine operation processing such as nonlinear processing is performed in units of frames in correspondence with each photographing frame. In order to effectively utilize the dynamic range of a digital processing circuit, there is provided an image processing apparatus which includes a varying circuit for varying the signal level in correspondence with the photographing contents, an A/D converter for converting an output varied by the varying circuit into a digital signal, an image memory for storing image information output from the A/D converter, an evaluation circuit for evaluating the image information, an operation circuit for performing operation processing of a signal output from the image memory, and a control circuit for controlling the varying circuit and the operation circuit on the basis of the evaluation result of the evaluation circuit.

Abstract: Image processing parameters for gradation correction of a digital image from a scene, which includes specular reflections may be seriously influenced by the presence of those specular reflections. Therefore, a method is developed to detect the presence of specular reflections in a scene, to modify the exposure time of the photo-sensitive means, which converts a luminous image to electronic image signals and to apply a gradation correction to the image data thus acquired. In one embodiment a digital camera is used to capture the image data, a cumulative histogram is built and two characteristic cumulative frequencies are used to determine via the histogram specular densities and highlight densities. The relative position of these density values indicates whether specular reflections are present, and give suitable parameters for setting an optimal exposure time and for computing a gradation correction curve.

Abstract: Compressing graphic data for a first computer system, e.g. an emulated system, on a second computer system. For each scanline of the graphic data for the first computer system, a number of colors present on the scanline are counted. A new color palette for the scanline is formed at a reduced representation. Then, a representation of each color of each pixel on the scanline is converted to the new palette. The scanline is then run-length encoded. The graphic data is compressed so that it can be, for example, transmitted between a client (e.g. an X client) and a server (e.g. an X server) and conserve network bandwidth.

Abstract: A specified lightness of a scanned image can be obtained by selecting from among plural gamma functions or by changing a light amount signal output by the line sensor of the scanning apparatus. Changing the light amount output may be accomplished by controlling the lighting time of each light source, or by adjusting the interval of a shift pulse of the line sensor, or by controlling the charge storage time of the line sensor. A controller adjusts the lighting time of the light source or the gradient of the gamma function in response to a specified lightness from an external computer so that image data in such specified lightness can be obtained. For example, in the case where the lightness is increased, if the user wishes a high quality image, the lighting time is increased, whereas if the user attaches importance to high speed reading, the gradient of the gamma function is increased.

Abstract: An input image is divided into relatively small blocks of pixels. Border data defining the areas are periodically calculated. For each pixel, a pair of selection pulses indicative of the area where the pixel is located is generated. In response to the pair of pulses, the gray scale characteristic is calculated for each area. The gray scale of the input image is corrected using one of the gray scale characteristic associated with each area to providing a corrected image signal for the area. In response to the pair of pulses, the corrected image signals are combined into an output image signal. An optimal gray scale correction is made for each area. The selection pulses are configured to gradually change near the borders thereby making the reproduced image appear natural.

Abstract: A gamma correction circuit comprising circuit apparatus for approximating in linear translation circuits successive nonlinear portions of a gamma correction curve, apparatus for applying an input luminance (Y) signal to the circuit apparatus, and selection apparatus for selecting signals translated by any of the circuit apparatus as a gamma corrected output signal depending on whether the input signal falls within predetermined ranges approximately corresponding to the nonlinear portions of the gamma correction curve.

Abstract: A digital still camera includes a shutter release button. A first gamma correction circuit, when a shutter release button is depressed, references a first gamma table to correct a camera signal by a gamma characteristic of a raster scan display, creating a first image signal. The first image signal is subjected to interpolation/thinning-out and image processing by a first signal processing circuit. A thinned-out image signal is corrected in a second gamma correction circuit by a gamma characteristic for converting a raster-scan display gamma characteristic into a dot-matrix display gamma characteristic, thereby creating a second image signal. The second image signal is displayed on an LCD (Liquid Crystal Display). The first image signal is also subjected by a second signal processing circuit to interpolation, YUV conversion and JPEC compression so that a compressed image signal is stored in a memory flash. The compressed image signal is read out of the flash memory as required, to be outputted to a CRT.

Abstract: A process for the adjustment of signals obtained from an image, in which analogue signals representative of the image are pre-emphasized and converted to digital signals. The digital signals are then de-emphasized and simultaneously or subsequently adjusted.

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 gamma correction circuit for use in a liquid crystal display device includes a comparator that receives an input data voltage and preferably three reference voltages. In response to these signals, the comparator outputs an input data comparison signal, which is supplied to first and second analog switches. The first and second analog switches select and respectively output a weight voltage and a correction voltage in response to the input data comparison signal. The selected correction voltages is then either added or subtracted from the input data voltage, and the resulting sum or difference is multiplied by the selected weight voltage using an analog multiplier.

Abstract: An image reading apparatus in which reference density data corresponding to a reference document having a predetermined reference density is stored in advance, while a plurality of gamma correction curves are also stored in advance. Light intensity data indicative of the intensity of light reflected from the reference document is subjected to a shading correction. One gamma correction curve is selected from the plurality of gamma correction curves in correspondence to a difference in output level between the reference density data and outputted density data obtained by converting the shading corrected light intensity data. Gradation of the outputted density data is adjusted based on the selected gamma correction curve.

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: According to an information signal correction processing apparatus of the invention which includes a plurality of clip circuits, a knee circuit, an adder, and a controller, an information signal which has been obtained through the clip circuits by clipping an input information signal in accordance with a plurality of clipping characteristics which have been arbitrarily set and an information signal which has been obtained through the knee circuit by voltage dividing the input information signal in accordance with a voltage dividing ratio which has been arbitrarily set are added by the adder and, when the resultant signal is outputted, the plurality of clipping characteristics and the voltage dividing ratio are respectively controlled by the controller, so that the information signal can be processed without being deteriorated.

Abstract: There is provided a novel and improved image pickup apparatus which can be reduced in size and low power consumption because of its reduced circuit scale and in which no degradation of image quality occurs at the switching points between a plurality of functions. Such an image pickup apparatus comprises a non-linear circuit for performing non-linear correction of a digitized video signal, and the non-linear circuit includes a multiplier having an input terminal formed by input bits the number of which is n.sub.1, n.sub.1, being selected to meet a relationship of n.sub.3 >n.sub.1, where n.sub.3 represents the number of input bits of the non-linear circuit. The non-linear circuit also has predetermined input ranges R.sub.i each of which is selected to be R.sub.i .ltoreq.2.sup.n1 -1, and is formed by a combination of characteristics of the respective predetermined input ranges R.sub.i.

Abstract: In an image pickup apparatus arranged to carry out a predetermined signal processing action including a gamma correction process on a signal outputted from an image sensor and to invert the signal during the process of the signal processing action, a varying circuit is arranged to vary a gamma value to be used for the gamma correction process.

Abstract: An image processing apparatus includes MTF correction part for converting an input multilevel image signal obtained via raster scanning into an output multilevel image signal through an MTF correction process, a first bi-level rendition part for performing a bi-level rendition process with respect to the output multilevel image signal so that a first bi-level image signal is produced, a second bi-level rendition part for performing a pseudo halftone rendition process with respect to the input multilevel image signal to generate a second bi-level image signal, a discrimination part for detecting whether a target pixel indicated by the input multilevel image signal is located in a halftone region of an original image or in a bi-level region thereof, and an image synthesizing part for outputting the first bi-level image signal to an output device when the target pixel is detected as being located in the bi-level region, and for outputting the second bi-level image signal to the output device when the target pixe

Abstract: An image input section selects a plurality of sample points from an input image, and passes the density values of the sample points and pixels around them to a feature parameter extractor. The feature parameter extractor calculates the feature parameters of each sample point and passes them to a density modification function generator. The density modification function generator creates a density modification function for each sample point and passes the density modification function data to a density modification function modifier. The density modification function modifier determines a density modification function for all of the pixels, including those other than the sample points, and passes this density modification function data to a processor. The processor modifies image data delivered from the image input section, and passes the modified image data to a modified image output section.

Abstract: An apparatus for gamma-correcting image data includes gamma characteristic corrector, a memory, a characteristic selector, and a microprocessor. The characteristic corrector inputs image data values and outputs gamma-corrected image data values corresponding to the image data values according to stored gamma correction information. The memory stores differential data values, and each of the differential data values corresponds to at least one of a plurality of gamma characteristics for gamma correcting the image data values. Furthermore, the differential data values respectively correspond to differences between two values of the gamma-corrected image data values. The characteristic selector outputs a gamma characteristic selection signal which represents a particular gamma characteristic of the plurality of gamma characteristics, and the microprocessor inputs the selection signal and reads particular differential data values from the memory which correspond to the particular gamma characteristic.

Abstract: A gamma correction circuit including a first look-up table in which minimum values of differences between output levels of a gamma correction curve and output levels of a straight line in respective sections formed by dividing a range from a minimum input level to a maximum input level into sixteen are stored. Furthermore, data of differences between the output levels of the gamma correction curve and levels obtained by adding the minimum values to the output levels of the straight line in the respective sections are stored in respective second look-up tables of sixteen. Then, one of the minimum values is read-out from the first look-up table according to upper four bits of input video data, and one of the second look-up tables is selectively enabled by the upper four bits, and data stored in the selected second look-up table is read-out in accordance with lower six bits of the input video data.

Abstract: A color camera capable of providing good dark gradation without color hue and saturation change is disclosed, the color camera comprising a picking-up device for converting an incident light into a video signal, a detector for detecting proportion of an area having a signal level below a predetermined dark level to produce a dark area proportion signal, and a stretching circuit for stretching a dark signal level in the video signal in accordance with the dark area proportion signal.

Abstract: A gamma correction circuit capable of faithfully monitoring and outputting the color and luminance of an object without deteriorating the resolution.

Abstract: A scanner system comprises an optical line detector for linewise, optical scanning of an original for generating a data signal in response to the grey-level received by the detector from points along a respective line. The points are sorted with associated grey-level values in groups in response to their positional origin on the original. The individual threshold values for the grey-level values are determined statistically for a plurality of zones on the original in response to the frequency of respective grey-level values in the respective zone. The threshold values of respective zones are stored in a store. The original is re-entered by linewise, optical scanning, and the data signal generated by the scanning and representing grey-levels in points along respective, entered lines is compared in a comparator with a threshold value calculated for the point concerned, and in response to this a binary, electric representation of the original is generated.

Abstract: A digital camera for processing a digital signal. The camera includes an image signal processing circuit which uses a low-resolution analog-to-digital converter. The processing circuit performs AGC and gamma control on both digital and analog signals. Gain control and gamma control are performed by auto gain controllers which either process an analog signal prior to converting the analog signal to a digital signal or after the analog signal is converted to a digital signal. The image signal processing circuit performs processing based on the output of one of a m-bit output of an AGC/gamma controller and a m-bit output of an A/D converter. The AGC/gamma controller receives an n-bit clamped image signal from a clamper, while the m-bit A/D converter receives an analog input. This selection operation minimizes the need for a high-resolution A/D converter.

Abstract: Disclosed is a color signal processing apparatus in which at least three types of color signals corresponding to filters are received from a solid-state image pickup element on which at least three types of color filters are formed, and linear matrix conversion of the at least three types of color signals determined by spectral characteristics of the corresponding color filters is performed to generate R, G, and B signals.

Abstract: A system and method for generating gamma-predistorted video signals. A close approximation to the ideal gamma predistorted values of Y, Cr and Cb video signal components are generated from linear camera or computer output signals using at most a single matrix multiplication, one channel of inverse gamma function generation (on the luminance component) and two table look up operations. The linear luminance value is predistorted by an inverse gamma function. If they are not available from the video source, a matrix multiplication is used to generate linear luminance and chrominance signals. The linear chrominance signals are then adjusted for their dependence on luminance using a two-dimensional table look-up. The lookup table(s) is (are) addressed by the linear luminance value and by each of the linear chrominance values to produce gamma-predistorted Cr and Cb signals from the tables.

Abstract: An improved electronic still imaging camera is described wherein electronic voltage values representative of an image are transformed according to an optimum tone scale mapping gamma curve. The gamma curve utilizes a subjective element along with an element associated with scene reflectivity to optimize tone scale variations according to steps in an analog-to-digital converter while reducing contouring in the image.

Abstract: In non-linear digital video processing, high frequency components resulting from the non-linearity may appear as spurious low frequencies due to mirror image spectral reflection in the sampling frequency fs. The non-linear circuit may be a gamma corrector (35). The effect of the alias components is reduced by the use of a modifier circuit (50) before the gamma corrector, and a corresponding equalizer circuit (52) after it. The modifier attenuates the high frequency signal components, especially in the region fs/4 to fs/2. The equalizer substantially reinstates the overall frequency response. Both modifier and equalizer may be transversal filters (FIGS. 5 to 8) which, more generally, may be one dimensional or two dimensional (FIGS. 9 and 10). The system is also particularly relevant to progressively scanned sources; including telecine.

Abstract: An image pickup apparatus comprises an image pickup section for converting an image of an object formed through a lens into an electric signal, a high frequency and low frequency separating circuit for separating the electric signal generated from the image pickup section into a high frequency component and a low frequency component, a gamma converting circuit for gamma correcting the electric signal of the low frequency component separated by the high frequency and low frequency separating circuit and a matrix circuit for adding the electric signal of the high frequency component separated by the low frequency and high frequency separating circuit and the electric signal of the low frequency component which was gamma corrected by the gamma converting circuit, thereby outputting a luminance signal and color difference signals.

Abstract: An image sensing device is provided with an expanded dynamic range when it photographs a moving object. A first gray value D1 of first picture taken with first exposure time is read in the first time interval and a second gray value D2 of second picture taken with second exposure time is read in the second time interval. Two function values f(D2) and g(D2) are calculated with respect to the second gray value D2. Then, a weight coefficient with respect to the function f(D2) is multiplied by the first gray value D1 and a weight coefficient with respect to the function g(D2) is multiplied by the second gray value D2. Those multiplied gray values are summed up. Such calculation of multiplying and summing up is carried out in each picture element of the first picture and the second picture, respectively.

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 video monitor contrast reference gray scale apparatus, and method of use thereof, wherein the apparatus comprises a reference gray scale housing, a reference gray scale which comprises a plurality of fields which provide a contrast range on the reference gray scale, a light source which is located inside the reference gray scale housing and which provides illumination to the reference gray scale, and a power supply for providing power to the light source. The reference gray scale is located in the reference gray scale housing, and further, the power supply provides power to the light source so as to provide illumination of the reference gray scale. A method for utilizing the apparatus for matching a contrast range of a camera video assist with a contrast range of a film camera negative. A method for matching a contrast range of a reference gray scale with a contrast range of a film camera negative, in conjunction with an adjustable contrast filter device and/or a camera viewfinder ocular.

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: A gamma correction circuit for converting N-bit input data into M-bit output data by using a gamma correction curve approximated by a polygonal line having a plurality of straight line sections each having a different slope, the gamma correction circuit including a calculation circuit for executing conversion calculation for each the straight line section; and a control circuit for controlling the calculation circuit in accordance with a value of the input data so that the calculation circuit executes the conversion calculation for each the straight line section corresponding to the value.

Abstract: An image pickup signal processing apparatus for generating a digital luminance signal and digital color difference signals from output signals from a solid-state image pickup element, includes subtracters for generating primary color signals or color difference signals from the output signals from the solid-state image pickup element, and an A/D converter for converting the primary color or color difference signals output from the subtracters into digital signals.

Abstract: An image pickup signal processing apparatus includes an A/D converter and a nonlinear signal processing circuit for comparing an image pickup signal input to the A/D converter and a voltage obtained by dividing a reference voltage of the A/D converter and nonlinearly processing the image pickup signal. The nonlinear signal processing circuit includes a negative feedback amplifier and circuit components for changing the amount of negative feedback provided by the negative feedback amplifier to generate nonlinear characteristics.

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: The present invention relates to an automatic focusing apparatus which permits an automatic focusing operation to occur with a high accuracy irrespective of the luminance of an object being sensed. The automatic focusing apparatus includes a focus lens, an image sensor, a focus motor for changing the position of the focus lens, a Y/C separating circuit for separating a luminance signal Y from the output of the image sensor, a non-linear circuit for subjecting the separated luminance signal Y to a non-linear processing, a high pass filter (HPE) extracting a high frequency component from the output of the non-linear circuit, an integrating circuit for integrating the extracted high frequency component and an in-focus detecting circuit for controlling the position of the focus lens based on the result of integration.

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: An automatic knee control circuit including a knee circuit for setting a knee point and a knee slope, a detecting circuit for detecting an output signal of the knee circuit and a comparing circuit for comparing an output of the detecting circuit with a reference voltage, wherein the knee circuit is controlled on the basis of an output of the comparing circuit. This automatic knee control circuit is characterized by a distributing circuit for distributing the output of the comparing circuit by an arbitrary distributing ratio, wherein the setting of the knee point is controlled by a first distributed output and the setting of the knee slope is controlled by a second distributed output, thereby making it possible to set a wide variety of signal processing states with ease. Therefore, pictures corresponding to cameraman's intention can be produced.

Abstract: A gamma correction circuit for single-plate type video camera having a correlation double sampling device and receiving the signal output from a complementary-filter-type charge coupled device (CCD) to thereby produce a color line sequence signal, includes a luminance signal detector for detecting the luminance signal frown the color line sequence signal; a first gamma-corrector for performing gamma-correction to the detected luminance signal from the luminance signal detector; a second gamma-corrector for gamma-correcting the color line sequence signal; a color difference signal detector for detecting the color difference signal from the color line sequence signal which is gamma-corrected by the second gamma-corrector; and a mixer for mixing the gamma-corrected luminance signal which is gamma-corrected by the first gamma-corrector with the gamma-corrected color difference signal which is detected by the color difference signal detector.