Abstract: An image display apparatus which employs a cathode ray tube displays, when an image displayed on a screen of the cathode ray tube is to be corrected against an inclination caused by the terrestrial magnetism, a reference for correction is displayed on the screen of the cathode ray tube so that correction current appropriate for correction of the image against the inclination caused by the terrestrial magnetism can be obtained in a short time.

Abstract: An image processing apparatus is disclosed by which correction of convergence and correction of distortion of an image can be performed with a high degree of accuracy. Correction data to be used for correction of position errors of the three colors of red, green and blue obtained by an adjustment apparatus in advance are stored in a storage section. The stored correction data are outputted to a correction waveform outputting section through a control circuit when necessary. The correction waveform outputting section produces correction waveforms based on the correction data inputted thereto and outputs the correction waveforms to a clock signal generation circuit. The clock signal generation circuit generates clocks, and the video data of red, green and blue stored in the memory are read out in response to the clock signals.

Abstract: In a method of preventing doming phenomena, luminance histogram distribution values are obtained (10) from a luminance signal, the various luminance histogram distribution values are processed and normalized (12), the luminance histogram distribution values are processed (16) to correct for at least actual contrast and brightness settings to obtain corrected histogram data, a beam current is predicted (18) from the corrected histogram data, and a correction signal is derived (20) from the predicted beam current and making said correction signal effective in the processing and normalizing step (12).

Abstract: A method for producing a plurality of successive output data values defining an output curve that approximates an input curve defined by a plurality of input sample values, the output data values having a higher sampling frequency than the input sample values, the method comprising the steps of: pre-emphasizing the plurality of input sample values; defining successive and overlapping intervals including at least three of the pre-emphasized input sample values; interpolating a plurality of the output data values in an interpolation interval by calculating a moving average of a linear interpolation curve based on the at least three pre-emphasized input sample values, each of the output data values being influenced by the at least three pre-emphasized input sample values; and, emphasizing differently the influence of the at least three pre-emphasized input sample values for determining different ones of the output data values in the interpolation interval, whereby the pre-emphasizing step brings the output curve

Abstract: A method for adjusting convergence in a projection television receiver, in which a marker contained in a projected image is adjusted by a manipulated variable to illuminate a photosensor arranged adjacent to the projection screen. The method employs two markers which are moved towards the sensor from opposite directions with a varying step size. The sensor supplies an output voltage indicating lighting by the two markers in conjunction with two mutually spaced manipulated variables. A mean value of the two manipulated variables is used as the manipulated variable for the marker.

Abstract: A convergence method for color television receiver comprises the steps of emitting a test signal from a control circuit to a first convergence channel to generate a current of a predetermined intensity in a convergence coil assigned thereto. The control circuit emitting a zero signal to the other convergence channels to generate zero current in the assigned convergence coils. Measuring and comparing with a reference potential a potential at a reference point of each convergence coil of channels driven by the zero signal. Generating a reference signal responsive to the comparison step b), for each case for the relevant convergence channel and coupling to the control circuit. Repeating steps a) to c) for each convergence channel, the convergence channels being driven in an alternating fashion one after another once in each case by a test signal.

Abstract: A method for generating a convergence correction curve from a plurality of successive output data values determined from a plurality of input sample values smaller in number than the plurality of output data values, the method comprising the steps of: defining successive and overlapping intervals including exactly three of the input sample values; interpolating a plurality of the output data values in an interpolation interval by calculating a moving average of a linear interpolation curve based on the three input sample values, each of the output data values being influenced by the three input sample values; emphasizing differently the influence of the three input sample values for determining different ones of the output data values in the interpolation interval; and, adjusting the input sample values to control convergence correction, whereby each incremental slope of the correction curve between adjacent output data values varies smoothly.

Abstract: A method and apparatus used to step and correct the position of raster lines in a sinusoidal or zig-zag deflection system. By combining the magnetic flux generated with a rotation “twister” coil and a vertical deflection coil, scan lines can be uniformly spaced and separated nearly to their ends. Accordingly, the magnetic flux generated with the twister coil is adjusted going in the left to right direction then reversed in polarity and readjusted while returning from right to left. It is this controlled twister flux that combines with the linear vertical deflection flux to straighten and then step each scan line to produce an aligned raster.

Abstract: A circuit for regulating a signal, such as a cathode current. The circuit has an input stage for inputting a signal and for producing a sense signal based thereon. The circuit may input timing signals and have a first stage for comparing a first reference signal with the sense signal when a first timing signal indicates and for outputting a first correction signal based on the comparison. The circuit may have a second stage for comparing a second reference signal with the sense signal when a second timing signal indicates and for outputting a second correction signal based on the comparison. The circuit may further have elements for measuring a leakage signal in the input signal during a third time interval. In this embodiment, the first and second stages are further for subtracting the leakage signal from the sense signal prior to the comparisons.

Abstract: A projection display device includes a screen image measuring arrangement and is subject to unwanted illumination. The measuring arrangement comprises a photo sensor located adjacent to an edge of the screen for generating an output signal having a first component responsive to illumination by a projected image and a second component responsive to illumination by the unwanted illumination. A filter is coupled to the photo sensor for filtering the output signal to pass the first component of the output signal and to attenuate an amplitude of the second component of the output signal.

Abstract: A convergence control method and apparatus for a projection television are provided. The convergence control apparatus includes an image signal decoder, a convergence control unit, and a main microcomputer. The image signal decoder processes an input image signal and generates a data signal and horizontal and vertical synchronization signals, and a start signal indicating the start of either the horizontal and vertical synchronization signals. The convergence control unit performs convergence adjustment according to a convergence control command it receives, and generates a completion signal when convergence adjustment is complete. The main microcomputer inputs the convergence control command to the convergence control unit when the start signal is input from the image signal decoder, and performs a control operation to display the image signal when the completion signal is input from the convergence control unit.

Abstract: In a CRT display apparatus, a horizontal distortion correction apparatus is provided for correcting horizontal distortion of an image by applying a residual phase to control the phase of a horizontal deflection current. The horizontal distortion correction apparatus corrects horizontal distortion of an image caused by an assembly error of the CRT display apparatus for displaying an image by scanning a video signal, based on a horizontal synchronizing signal included in the video signal. The horizontal distortion correction apparatus includes a PLL supplying the horizontal deflection current to a video signal controller for displaying an image on the CRT. A distortion-correcting waveform generator is operated by the user, applying a wave signal having a desired waveform to the PLL to provide a residual phase for the horizontal deflection current to control the phase thereof. As a result, the image without horizontal distortion is displayed on the CRT display apparatus.

Abstract: For control and correction of deflection parameters especially of convergence, a grid pattern is displayed on the picture screen of a television device. For control of the convergence parameters and the evaluation of the correction values the crossing points of the grid pattern are marked by a cursor. The cursor is formed by at least one irregularity in the grid pattern being, regular otherwise. The irregularity may consist in an omission within the grid pattern like an interruption within one horizontal or vertical grid line. An image signal generator for the grid pattern with position cursor includes a raster generator, a grid generator, a cursor generator, and means for combining a grid signal from the grid generator and a cursor signal from the cursor generator so as to inhibit the grid signal corresponding to locations on the grid pattern where the position cursor is visible by an absence of display of portions of the grid pattern.

Abstract: Anode voltages A′ and B′ corresponding to video signals A and B are switched by a first switch and supplied to an anode. Cut-off voltages A and B corresponding to the video signals A and B are switched by a second switch and added to a video signal by an adder. A resultant signal is supplied to a cathode. In a CRT, the luminance rises in association with the step-down of the cut-off voltage and the step-up of the anode voltage and the resolution rises in association with the step-up of the cut-off voltage and the step-up of the anode voltage. The first and second switches are switched in accordance with the format of the input video signal respectively, thereby properly selecting the anode voltage which is applied to the CRT and the cut-off voltage. The video image can be displayed by the CRT at the luminance and resolution according to the video signal without changing a driving voltage.

Abstract: A problem to be solved by the invention is to prevent a digital convergence correction device from lowering in precision of correction performed when a relation between screen raster and effective area of picture varies. A vertical display area detection signal that corresponds to a position in vertical direction of a picture display area on a screen is generated in accordance with a vertical deflecting current. An address counter for generating an address for reading out correction data is controlled in accordance with the signal.

Abstract: Provided are an image correcting method and device capable of reducing power consumption necessary for correcting an image for a long-time use and a cathode ray tube display unit. A microcomputer 2 calculates a value of a correction current in such a manner that the correction current is more decreased monotonously as a time passes after a cathode ray tube is turned on. Drivers 3 to 7 and 22 generate and output the correction current according to the value of the correction current calculated by the microcomputer 2. A correcting device C is provided in the cathode ray tube and serves to correct an image displayed on the cathode ray tube on receipt of the correction currents from the drivers 3 to 7 and 22.

Abstract: A method for measuring a convergence of color CRT uses a combination pattern among Red(R), Green(G) and Blue(B) colors on a white pattern when measuring convergence by using a color camera so that convergence is measured with a high degree of precision. The method sequentially generates two test patterns after mixing two colors chosen from among red(R), green(G), and blue(B) colors, e.g., mixtures of red(R)/blue(B) and green(G)/blue(B). Images are independently obtained of the two test patterns formed on the color CRT screen, and a signal conversion is performed based on each independently obtained pattern image to produce image information. The image information is stored and a convergence of the stored image information for each test pattern is calculated.

Abstract: In a system according to the invention, fine image data 2 created and output by a personal computer 1 is input to an image processing/dividing section 4. The image processing/dividing section 4 determines, on the basis of parameters stored in a projector arrangement storage 5, which portion of the fine image data 2 is output to which projector, thereby performing a predetermined processing. Digital signals from the image processing/dividing section 4 are input to a plurality of D/A converters 6, respectively, where the signals are converted to analog signals. Images in the form of the analog signals are projected onto a screen 8 from projectors 7a-7d. Thus, the image projected on the screen 8 is constituted of accurately positioned images, and hence is a very fine image.

Abstract: Convergence control apparatus of a projection television has: a pattern generator for generating a reference pattern; optical sensors for sensing the change of luminance of the reference pattern moving on a screen; and a convergence controller for compensating for the tilt of the reference pattern based on the output of the optical sensors. The optical sensors are respectively disposed at opposite sides on the screen. The convergence controller detects the angular error of the reference pattern distorted by earth's magnetic field, based on the difference between a standard position and a measured position of a maximum luminance of the reference pattern, and controls a deflection circuit to compensate for the angular error. When the image displayed on the screen is tilted by the influence of the earth's magnetic field, the tilt of the picture can be compensated. After completing the compensation for the angular error, a positional error of CRTs for R, G, and B colors is also compensated.

Abstract: In a color display device, apparatus and method are provided to produce a convergence correction signal based on digital convergence correction values. The data rate by which the data is supplied to the apparatus varies, depending on the area of the display corresponding to the digital convergence correction values being supplied.

Abstract: A Circuit for conditioning sync signals for devices for the line-by-line Display of video signals includes, a first input for horizontal sync signals (H1sync, H2sync), a second input for vertical sync signals (Vsync), and a delay stage. The delay stage outputs a signal (Vshift) which is delayed relative to the vertical sync signal (Vsync) by a specific delay time (reg). The circuit determines the timing of the horizontal sync signals (H1sync, H2sync) relative to the vertical sync signal (Vsync) and/or relative to the delayed signal (Vshift). The delay stage is designed in such a way that the delay time (reg) is adjustable.

Abstract: An apparatus and method are provided for measuring convergence of the Red-Green-Blue (R.G.B.) signals of a color cathode ray tube (CRT) using a color charge coupled device (CCD) camera. A uniform R.G.B. brightness value is picked up by the color CCD camera at all positions of the CRT screen when the color CCD camera images the screen, thus enabling convergence to be more accurately measured and adjusted. Test patterns having a constant R.G.B. brightness value are displayed on the screen of the CRT by a pattern generator. The displayed test patterns are picked up by the color CCD camera, and when the R.G.B. brightness values differ from a corresponding reference brightness value, a controller adjusts the intensity of each of the R.G.B. signals of each test pattern by suitably controlling the pattern generator. A uniform R.G.B. brightness value is thus provided for all test patterns displayed on the CRT screen. Only after the R.G.B.

Abstract: A universal device provided with means to be controlled by a control unit which forms part of a projector. The device, in conjunction with this control unit, can be used for the automatic adjustment of the projector. More specifically, the adjustments of convergence, geometry, focus, astigmatism, contrast modulation, gamma correction, soft edge, adjacent and overlapping geometry. In addition, the device provides support for non-adjustment tasks such as signal decoding, signal testing and analysis, peak detection, RAM expansion, wire-free transmission of information between at least two projectors. The universal device exhibits different operational characteristics in accordance with different applications imposed on it by the control unit of the projector. The device includes an analog-to-digital converter, a memory, a programmable digital component, and an interface to the control unit of the projector as some of the components.

Abstract: An image display correcting apparatus of the invention comprises, broadly, a correction data forming apparatus and an image display apparatus. Correction data for correcting a display state of an image is formed by the correction data forming apparatus on the basis of an image as a reference displayed on the screen of a CRT. Further, on the basis of the correction data, an operation of correcting image data is executed so that an image is accurately displayed on the image display apparatus. The corrected image data is outputted to the CRT. Thus, a defective display state such as image distortion, misconvergence, or the like can be corrected at low cost and a high quality image can be displayed.

Abstract: In a video display, correction data for a digital convergence arrangement are stored in a first non-volatile memory. During power turn on procedure, the correction data are read out of and stored in a volatile memory. During each deflection cycle, the data stored in the volatile memory are successively read out and applied to an auxiliary convergence winding. When a parity error is detected in the read out data, the data stored in a second non-volatile memory are automatically read out and transferred to the volatile memory and to the first non-volatile memory. The second non-volatile memory contains a duplicate of the correction data stored in the first non-volatile memory, during factory set up. The data in the second non-volatile memory are maintained parity error free. Thereby the parity error containing data stored in the first non-volatile memory are substituted with the data that are free of parity error, provided by the second, non-volatile memory.

Abstract: An image control device and method, and image display device, capable of producing an image of high quality by joining a plurality of divided frames with the joint areas made inconspicuous. An index electrode is provided in an over-scan region on the side of the joint area of the right and left divided frames. The index electrode outputs a detection signal in response to an electron beam scanning in the over-scan region. Based on the detection signal, obtained is data on a pixel position in the joint area of the divided frames. Further, based on the data on the pixel position thus obtained, estimated is data on a pixel position in an area other than the joint area of the divided frames. Meanwhile, using data obtained based on the detection signal outputted from the index electrode, control of image data is exerted so that the left and right divided frames are joined properly.

Abstract: The invention and method enable the astigmatism correction at each crossing point of a cross hatch pattern, thereby making high-resolution display possible. An appropriate voltage or current for controlling the magnetic field adjusting coils are generated from the correction data stored in a memory. The voltage or current generated are then applied to two poles, four poles or six poles during scanning of the screen.

Abstract: A deflection-distortion correcting circuit for correcting deflection-distortion of an image on a screen by modulating a source voltage for horizontal deflection is disclosed. The deflection-distortion correcting circuit includes a first correcting data generating unit for generating a first correcting data for an image display period, a second correcting data generating unit for generating a second correcting data for a vertical blanking period, deflection-distortion correcting signal generating unit for generating a correcting signal for the image display period and the vertical blanking period in accordance with the first and second correcting data, and a horizontal-deflection circuit which modulates a source voltage for horizontal deflection with the correcting signal.

Abstract: A color display device includes a color cathode ray tube having a phosphor screen, a color selection electrode and an electron gun for projecting plural in-line electron beams toward the phosphor screen, a deflection device for deflecting the electron beams horizontally and vertically, an electron beam correction apparatus including a correction coil wound around the tube axis, a deflection circuit for driving the deflection device, and an electron beam correction circuit for supplying to the electron beam correction apparatus a generally rectangular-wave signal having a period equal to two times a period of the vertical deflection of the electron beams and in synchronism with the vertical deflection of the electron beams.

Abstract: A method and system for providing two-dimensional convergence correction for a color cathode ray tube (CRT) is disclosed. The CRT displays an input video signal comprising a stream of video scan lines which include red, green and blue color signals that are to be displayed on corresponding scan lines and subpixel locations of a display screen. The method and system include storing a plurality of scan lines from the video signal into a buffer. For a particular red, green and blue color signal, horizontal and vertical distortion of the red and blue subpixels in relation to a position of the green subpixel on the display screen are measured. Then, at least one math function is generated that mathematically represents the distortions. Finally, the math functions are applied to control circuitry to control timing of red and blue subpixels read from the frame buffer so that output of the red and blue subpixels are coincident with output of the green subpixel on the display screen.

Abstract: An apparatus for convergence correction in a TV receiver with a CRT display comprises a display screen with photo sensors positioned adjacent to screen edges. A cathode ray tube generates a raster for illuminating the display screen and the photo sensors. A signal generator generates a video signal having a first part for convergence alignment and a second part having sufficient video signal amplitude to cause an average level of beam current loading corresponding to an average level that can occur during broadcast video reception. The video signal being coupled to the cathode ray tube for illuminating the display screen and sensors. The video signal facilitating convergence alignment with the average level of beam current loading to ensure that convergence alignment is maintained during broadcast video reception.

Abstract: A convergence correction circuit including a coordinate unit which sets a predetermined range with first level values according to a screen length; an interval unit which divides the screen length; an interval decoder which calculates the value of the branch point of each interval determined by the interval unit; an interval gain unit which stores the gain of each interval; a subtracter which subtracts the output of the coordinate unit from the output of the interval decoder; a multiplier which multiplies the output of the subtracter by the output of the interval gain unit; a level shifter which sets an initial and last value of each interval upon horizontal scanning; an adder which adds the output of the multiplier and the output of the level shifter; a digital-analog converter which converts the output of the adder; and a correction coil which corrects the convergence according to the converted output.

Abstract: In a method of preventing doming phenomena, luminance histogram distribution values are obtained (10) from a luminance signal, the various luminance histogram distribution values are processed and normalized (12), the luminance histogram distribution values are processed (16) to correct for at least actual contrast and brightness settings to obtain corrected histogram data, a beam current is predicted (18) from the corrected histogram data, and a correction signal is derived (20) from the predicted beam current and making said correction signal effective in the processing and normalizing step (12).

Abstract: An image processing apparatus is disclosed by which correction of convergence and correction of distortion of an image can be performed with a high degree of accuracy. Correction data to be used for correction of position errors of the three colors of red, green and blue obtained by an adjustment apparatus in advance are stored in a storage section. The stored correction data are outputted to a correction waveform outputting section through a control circuit when necessary. The correction waveform outputting section produces correction waveforms based on the correction data inputted thereto and outputs the correction waveforms to a clock signal generation circuit. The clock signal generation circuit generates clocks, and the video data of red, green and blue stored in the memory are read out in response to the clock signals.

Abstract: A television system performs beam convergence in video displays. The system is implemented through one or more convergence sensors, which are exposed to two distinct convergence test patterns. The output signals from the sensors when exposed to the two convergence test patterns are used in beam convergence calculations. The convergence test patterns are selected to reduce the dynamic range requirement for an A/D converter in the television system supplied with the sensor output signals.

Abstract: A television system performs beam convergence in video displays. The system is implemented through one or more convergence sensors, which are exposed to two distinct convergence test patterns. The output signals from the sensors when exposed to the two test patterns are used in beam convergence calculations. The test patterns are selected to reduce the dynamic range requirement for an A/D converter in the television system supplied with the sensor output signals. A low-pass filter circuit with selectable characteristics is also used to reduce the dynamic range requirement.

Abstract: Each horizontal deflection coil 2 comprises the smaller diameter flange 2A. A width “b” of the smaller diameter flange 2A in the horizontal direction of a screen of a color picture tube is more than twice a height “a” of the smaller diameter flange 2A in the vertical direction of the screen.

Abstract: A method for convergence correction in a television receiver and to a television receiver, in particular a projection television receiver having in each case one monochromatic picture tube for the three primary colours, red, green and blue, improves the quality of convergence correction. Each picture tube is assigned a correction device which comprises a convergence circuit. The convergence circuit is assigned a memory in which correction values for the convergence correction of the three picture tubes are stored. In accordance with the correction values, the convergence circuit generates output signals, which are output to a correction device, which in each case comprise at least one correction coil and, for each correction coil, one driver circuit. A correction current is applied to the associated correction coil in order to correct image defects of a picture tube.

Abstract: A convergence correcting apparatus and method of a television for automatically correcting convergence in consideration of terrestrial magnetism of a television location set by a user. Convergence is adaptively corrected in consideration of the terrestrial magnetism of a territory at which a television is installed, thereby preventing picture quality from deteriorating due to differences in the terrestrial magnetism of different territories.

Abstract: A problem to be solved by the invention is to provide a digital convergence correction device capable of coping with variation in scanning frequency at a reasonable price. The digital convergence correction device comprises a gate circuit for storing a variation in each convergence correction amount in a memory as correction data, and reading out the correction data synchronously with screen scanning at the time of integrating the correction data and causing the output time to be constant for each of the correction data read out.

Abstract: The invention relates to a television receiver, in particular a projection television receiver having red, green and blue monochromatic picture tubes, the images of which are projected onto a picture screen. Each picture tube is assigned a correction device comprising a convergence circuit. The convergence circuit is assigned a memory in which correction values for the convergence correction of the three picture tubes are stored. In accordance with the correction values, the convergence circuit generates control signals, which are output to at least one correction coil where each correction coil has one driver circuit. A correction current is applied to the associated correction coil to correct image defects visible on each picture tube.

Abstract: Disclosed is a high-speed approximation device that generates zone correction values in both the horizontal and vertical directions. Group correction values are stored for specific physical locations on the screen for each correction factor parameter. Higher resolution correction signals can be produced by generating zone correction values. Zone correction values are produced for binary fractional addresses that correspond to specific physical locations on the screen. By addressing specific binary fractional addresses that correspond to the location of the video image on the screen, new group correction values do not have to be produced each time the horizontal or vertical size or centering or frequency of the video image is changed. Additionally, by using start addresses and end addresses, zone correction values only have to be produced for the area which the video image occupies on the screen.

Abstract: Image data of the respective colors are converted, by look-up tables in which &ggr; correction data are stored, into gradation data that are white-balanced with intervention of the V-T characteristics of liquid crystal panels. The generated gradation data are supplied to D/A converters and the liquid crystal panels via liquid crystal driving circuits. Gamma correction data within dynamic ranges that are set for each display apparatus by measuring a luminance ratio and contrast ratios of the respective colors are written to the look-up tables in advance. As a result, all they correction data stored in the look-up tables can be used effectively. The invention is directed to such a method for generating data of look-up tables and an image display apparatus that performs gradation correction by using thus-formed look-up tables.

Abstract: A video imaging apparatus includes a source of a blanking signal that is indicative when a blanking interval occurs in a video signal. A delay circuit including a horizontal line counter is responsive to the blanking signal and to a signal at the horizontal rate for delaying the blanking signal by a multiple number of horizontal periods to generate a delayed signal. A dynamic focus voltage generator includes a switch responsive to the delayed signal for applying a dynamic focus voltage to a focus electrode, when the switch is at a first state, and for disabling the application of the dynamic focus voltage, when the switch is at a second state. An end time of the interval, during which the dynamic focus voltage is disabled, is determined in accordance with an output signal of the counter.

Abstract: In a system according to the invention, fine image data 2 created and output by a personal computer 1 is input to an image processing/dividing section 4. The image processing/dividing section 4 determines, on the basis of parameters stored in a projector arrangement storage 5, which portion of the fine image data 2 is output to which projector, thereby performing a predetermined processing. Digital signals from the image processing/dividing section 4 are input to a plurality of D/A converters 6, respectively, where the signals are converted to analog signals. Images in the form of the analog signals are projected onto a screen 8 from projectors 7a-7d. Thus, the image projected on the screen 8 is constituted of accurately positioned images, and hence is a very fine image.

Abstract: A system and method for controlling a video display blanking signal so as to maintain a full display screen while minimizing interference with the displayed picture. To control the blanking signal one or more photosensors are placed at the periphery of the display screen. When a CRT overscans the screen at a sensor's location, the light from the CRT is incident on the sensor and the sensor generates a signal proportional to the amount of incident light. The sensor signal is used to adjust the CRT scan such that the CRT scan covers the screen but does not degrade the displayed picture.

Abstract: Accurate measurements of the misconvergence of a color CRT are obtained using a monochrome CCD camera or the like and a common image. In accordance with one embodiment of the invention, color misconvergence of a color video display is determined using a monochrome camera, by capturing a monochrome image of an output display displayed on the color video display. For each of multiple different colors, information from the monochrome image is processed to identify a displayed feature or feature pattern of that color, and a position of that displayed feature or feature pattern is determined. Then a difference in position of a feature or feature pattern of a first color and a feature or feature pattern of a second color is determined. The effects of color crosstalk, video/image jitter, and lens distortion are all eliminated or minimized.

Abstract: A method of electronic Keystone correction for electronic devices having visual displays which exhibit optical distortion on the display screen. The corrective method is based on computation and electronic (physical) manipulation of the pixels of a visual display screen grid, and features the principle steps of: 1) characterization of the size of an input image, 2) determination of the number of generated pixels in the output image, 3) determination of the real position of each pixel in the output image by performing an electronic distortion to the input image opposite to the optical distortion of the input image, 4) interpolation of the output value of all color components of each pixel of the input image, 5) correction of (non-uniform) edge effects at both ends of each line of pixels, 6) transmission of the output corrected image to the electronic display device, individually, pixel by pixel, or as complete set of corrected pixels of the image, and 7) display of the perfected corrected optical image.

Abstract: System and method for improving color convergence in projection display systems employs one or more mirror units disposed for reflecting light from the projection lens to a display screen, each mirror unit including one or more reflective layers adjustably positioned for changing the path length of selected one or more color components of the color image.

Abstract: A method and apparatus for reducing visibility of damping wire artifacts in aperture grill display tubes comprises a sensor device for locating the artifacts and responsively generating amplitude values, a processor for receiving the generated amplitude values and responsively calculating correction values, and a compensator device coupled to the processor for utilizing the correction values to correct said artifacts.