Abstract: A memory and a switchable digital filter supply different numbers of digital distortion correction values. The supplied distortion correction values are converted to an analog distortion correction signal. A passive, analog low pass filter for the analog distortion correction signal generates an analog deflection signal. The low pass filter is optimized only for those of the analog deflection signals having a given sample rate. A controller varies the different numbers of the supplied distortion correction values to maintain the given sample rate of the analog deflection signal for different horizontal scanning rates. The controller selectively implements respective operating modes for different horizontal scanning frequencies in which no interpolated distortion correction values are supplied or different numbers of interpolated distortion correction values are supplied.

Abstract: A shadowmaskless tracking cathode ray tube control circuit is described, comprising a control loop, which is coupled to a deflection unit of a shadowmaskless tracking cathode ray tube. The shadowmaskless tracking cathode ray tube control circuit further comprises a loop gain control means for compensating the loop gain of the control loop in dependence on the inverse value of the beam current in the shadowmaskless tracking cathode ray tube. The effect is that a constant loop gain is created, which is independent of the beam current.

Abstract: An image correction method of compensating for point of view image distortion in pictures includes the steps of obtaining an image at a first position within a predetermined frame, wherein at the first position the image is distorted due to point of view image distortion. The image obtained comprises an array of pixels. The distorted image is transformed into a compensated image by re-mapping the array of pixels of the distorted image using a predetermined transforming function that stretches the distorted image to fill the entire frame. The transformation function depends on the geometric orientation of the camera, projector, projecting surface, and viewer. The compensated image is projected at a second position different from the first position, wherein the projection of the compensated image substantially reduces point of view image distortion at the first position. This method can be employed for stationary and moving point of views.

Abstract: An image processing apparatus for use in a display system comprises a display device for viewing image, and a geometric transformation module that is configured to precondition said image data with geometric transformations to thereby compensate for characteristics of the display system. The geometric transformation module may include a spatial transformation module for redefining spatial relationships between image pixels, an alignment and rotation correction module for repositioning image pixels, a focus correction module for correcting image defocus, a distortion correction module for correcting image distortions, and a multi-frame correlation module for performing motion-compensated frame rate conversion.

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 focus compensation apparatus and method for a monitor system are provided. The focus compensation apparatus includes a parabolic signal generation circuit for generating a parabolic signal in synchronization with a horizontal flyback pulse, the waveform of the parabolic signal varying in response to first and second control signals. A video signal focus compensator adjusts the gain of an input video signal such that the gain increases from the center of the monitor screen toward the edge of the monitor screen in response to the parabolic signal. The focus compensator outputs a gain-adjusted video signal as a focus-compensated video signal. According to the focus compensation apparatus, the gain of an input video signal is adjusted using a parabolic signal, the level of which increases from the center of a monitor screen toward the edge of the monitor screen, thereby preventing a picture from being out of focus and blurred at the edge of the monitor screen.

Abstract: A method and apparatus for preventing keystone distortion. A projected image is produced by projecting light through a display image rendered on a display device (e.g., and LCD panel) and onto a viewing surface at a non-perpendicular vertical and/or horizontal angle. An original image is deformed in proportion to the angle(s) to produce the display image. The original image may also be resized for storage in memory and/or to fit within a specified or usable area of the display device. An apparatus for preventing keystone distortion includes a digitizer module to receive and resize an original image (e.g., reduce it) for storage and a generator module to resize (e.g., enlarge) the image to fit the display device. Deformation of the image to prevent keystone distortion may be performed in either or both of the digitizer and generator for either or both a vertical and horizontal angle.

Abstract: A projector is often positioned so that its optical axis is at an imperfect orthogonal angle with respect to a projection screen. This position causes a keystone distortion as well as imperfect focus in the projected image. To correct these undesirable problems, initially, a lens and/or an image-forming plate is independently repositioned to bring the projected image into focus based upon user input data. The keystone distortion is also corrected by redrawing the image on an image-forming surface based upon additional user input data.

Abstract: A display method and apparatus for displaying information by projecting a light onto an external projection plane is capable of detecting a deviation amount of a displayed image projected on the projection plane with respect to the display apparatus. Output image data is changed based on the detected deviation amount to offset a distortion of the displayed image, which is displayed using the changed output image data.

Abstract: A projection display comprises a display device forming an image for projection onto a display screen. A photo sensor is adjacent to the display screen and generates a first signal responsive to a level of the projected image illumination incident on the photo sensor. A detector is coupled to receive the first signal and generates an output signal indicative of detecting the first signal. A source of a predetermined detection threshold value is coupled to the detector for determining a threshold at which the detection of the first signal occurs. Wherein the first signal exceeds the predetermined detection threshold value, the detector detects and generates the output signal indicative of signal detection, and generates a second signal for coupling to the source to change the predetermined detection threshold value.

Abstract: A system for processing a video signal is described. Components of the video signal, such as the horizontal sync signal, undergo time delays as the signal propagates and is processed by circuit elements. In order to properly align the components of the video signal for further processing, compensation for the different time delays is introduced.

Abstract: A method and apparatus for centering an active video signal on a display screen is described. In one embodiment, the method includes calculating an initial positioning value, which corresponds to an initial position of the active video signal on the display screen. A target positioning value is then determined using linear interpolation. The target positioning value is a rough estimate and provides a big pre-jump of the active video signal from the initial position to a target position, which positions the active video signal near the center of the display screen. A bi-sectional fine tuning technique may then be utilized to center the active video signal on the display screen. This method may be performed using a feedback loop that comprises a microcontroller, a digital signal processor, and an on-screen display circuit.

Abstract: Determining a phase shift compensation for automatically centering an image by measuring a start time delay between a horizontal scan line signal and an active video signal, measuring an end time delay between the active video signal and the horizontal scan line signal, and computing a phase shift for a horizontal flyback signal using the start time delay and the end time delay. A system to center an image on a monitor includes a video processing circuit and a rasterizer. The video processing circuit receives a video signal and measures a start time delay and an end time delay between a horizontal scan line signal and an active video signal. The circuit generates a phase shift used to generate a horizontal flyback signal using the measured start time delay and the end time delay. The rasterizer receives the output of the video processing circuit to control a scanning element.

Abstract: A method of measuring an illuminance distribution on a substrate; which is characterized in that the method comprises a step of reciprocatively moving a detecting sensor positioned on a substrate stage along a route during which the detecting sensor is intermittently stopped at a plurality of locations within an exposure region over the substrate, and, after reaching a turning location, moved to return along the route during which the detecting sensor is intermittently stopped again at these locations; in that measurement of illuminance is performed an even number of times at each location; and in that the illuminance distribution in the exposure region over the substrate is determined based not only on a measured value of illuminance obtained at each location during the forward movement of the detecting sensor but also on a measured value of illuminance obtained at each location during the returning movement of the detecting sensor.

Abstract: A method of automatically adjusting a CRT color monitor screen and a CRT color monitor are provided in which the horizontal position and size in a horizontal frequency of 100 kHz or so are adjusted at an acceptable accuracy thus reducing the overall cost by steps of examining with a comparison circuit 6, a one-shot circuit 7, and a microcomputer 9 whether a location determining pulse overlaps with a synthetic signal or not while shifting the phase of the location determining pulse in relation to a horizontal synchronizing signal HD, detecting the location of picture signal part of a video signal relative to the horizontal synchronizing signal HD from the result of examination, and automatically adjusting the horizontal position and the horizontal size on the screen in accordance with the result of detection.

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: A circuitry for attaining a fixed raster vertical scan size of a video display apparatus is proposed. The video display apparatus comprises a flyback transformer (FBT) which includes a primary winding and a secondary winding. The secondary winding has a terminal generating a high voltage to an anode of a cathode ray tube (CRT) of the video display apparatus via an external loading. Moreover, the secondary winding has a voltage reference terminal. The raster vertical scan size adjustment circuit comprises a compensation circuit and a raster vertical scan size control circuit. The compensation circuit includes an input terminal adapted to connect the voltage reference terminal of the secondary winding for detecting voltage change at the voltage reference terminal responsive to variation of the external loading. The compensation circuit has an output terminal generating the compensated signal.

Abstract: A set of coarse or initial convergence correction values for a model line of projection television receivers is defined in digital form prior to production using a fine grid or grating pattern. The set of coarse convergence correction values is digitally stored in all the receivers of the model line. A receiver-specific set of fine or final convergence correction values is defined in digital form for each receiver in the model line using a coarse grid or grating pattern. In each receiver, the receiver-specific set of fine or final convergence correction values is combined with the stored set of coarse convergence correction values. Convergence correction during subsequent operation of each receiver is based on the combined convergence correction values. Some of the coarse and fine convergence correction values can be located horizontally outside of the visible picture area of the receivers.

Abstract: A video display system includes a laser beam that is reflected from a vertical scan rotating mirror, then from a horizontal scan rotating mirror and then toward a viewing surface. The rotational angles of the mirrors and the intensity of the laser are controlled by a controller that is driven by a video signal. Rotation of the horizontal mirror scans the laser beam across the viewing surface while the laser intensity is modulated to form pixels on the viewing surface. The vertical scan mirror then directs the beam to the next horizontal scan line. The resolution and aspect ratio of the image are adjusted by changing the rotation rate of the mirrors and by changing the rate at which the laser is modulated.

Abstract: A convergence correction circuit, for a cathode ray tube projecting images having keystone, differential sinusoidal and differential right-edge curl distortions, comprises generators for horizontal-rate, generally sinusoidal, horizontal-rate sawtooth and horizontal-rate pulse waveforms. A summer combines the horizontal-rate waveforms into a horizontal-rate composite waveform. A multiplier and an amplifier generate as an output signal a product of the horizontal-rate composite waveform and a vertical-rate sawtooth waveform. A convergence correction coil is coupled for receiving the output signal and generating a dynamic magnetic field correcting the keystone, differential sinusoidal and differential right-edge curl distortions.

Abstract: A self adjusting tiled image display system and method is provided. In operation, an image source having an array of tiled image displays projects a test image pattern. A positioning device is attached to a corresponding one of the image displays for positioning that image display. A sensor senses the test image pattern projected by the image displays and generates a sensor signal indicative of the sensed test image pattern. A processor compares the sensor signal to a proper alignment signal indicative of the image displays being properly aligned to generate a positioning signal. The processor applies the positioning signal to the positioning devices to position the image displays as a function of the positioning signal until the image displays are in the proper alignment.

Abstract: A horizontal size adjustment circuit and method and for use with a monitor that includes a microcomputer for receiving a horizontal size adjustment signal, a horizontal synchronizing signal and a feedback signal from a horizontal output circuit, and for producing a digital pulse width modulated signal at its output terminal; a current amplifier for amplifying the amplitude of the digital pulse width modulated signal output from the microcomputer so as to drive a switching transformer and a horizontal output circuit for generating a variably controlled horizontal size signal.

Abstract: When two projecting units or more project two pictures or more obtained from video signals and luminance levels of projected pictures at an overlapped portion thereof are adjusted, a picture to be adjusted is selected from the projected pictures. One of processings for adjusting a correction start point of a correction data, a correction end point thereof and an inclination of a correction curve thereof to be used for a picture adjustment is selected. When the positions of a correction start point and/or a correction end point of the correction data are adjusted by using a remote controller unit or the like, a mark data is superposed on the correction start point and/or the correction end point of the correction data to display a mark formed based on the mark data on the screen together with the projected pictures. Thus, the picture is adjusted by displaying the marks together with the projected pictures.

Abstract: Such vertical deflection polarity switching circuit for CRT projector can be provided that enables external, one-shot operational switching of the vertical deflection polarity. To switch a CRT projector from a hanging type to a floor type, the switching circuit receives a vertical deflection polarity switching signal from an external device, so that an input sawtooth waveform polarity switching circuit will switch the polarity of a V. SAW signal. At the same time as the polarity of the input sawtooth waveform is switched, power-supply switching circuits switch the driving power-supply voltage of a vertical deflection-use output amplifier. Thus, the polarity of voltage waveforms applied to a vertical deflection yoke is inverted. Also, the polarity of vertical deflection and that of vertical-system data of correction waveforms for use in each of output circuits for horizontal deflection convergence focus are switched.

Abstract: A side pincushion control apparatus for compensating for a horizontal picture size control voltage and a side pincushion in a monitor. The apparatus compensates for the horizontal picture size control voltage and the side pincushion of the picture using a microcomputer, so that the picture is prevented from being unstable during the side pincushion compensation.

Abstract: A video signal processing apparatus includes synchronizing signal separation (31) for extracting a synchronization information of an input video signal, a reference clock signal source (32) for generating a signal having a constant period, phase synchronization control (33) which receives input with a clock signal output from the reference clock signal source and which outputs a phase-locked clock signal at a timing of outputting the synchronization information, and a memory (35) for storing a correction data used for correcting a video signal of one scanning line amount. The correction data is read out from the memory (35) based on the clock signal to process the input video signal. When a synthesized picture is projected, the correction data is a data which permits a luminance level of the video signal of each scanning line amount to be faded in and/or faded out at a start portion and/or an end portion thereof linearly or like a predetermined curve.

Abstract: An image-projection display (10) includes a combiner (12) which is transparent to allow a view therethrough, and which is also at least partially reflective so that an image projected onto a surface of the combiner is reflected to a viewer. The display apparatus includes off-axis projection factors so that a rectilinear projected image would be perceived by the viewer as being distorted. A projector portion (20) of the display (10) includes an image source (36, 38) and a corrector element (46), as well as means (38, 46) for physically dislocating pixel elements of a rectilinear image so that the image as projected is de-linearized with compensatory distortion causing the image viewed by the viewer to be perceived with restored rectilinearity.

Abstract: In a projection system for projecting a video picture composed of picture points on a screen with at least one light source which emits a light bundle and can be varied in intensity and with a deflecting device which deflects the light bundle to illuminate the picture points on the screen, a transformation optical system having at least two stages is arranged between the deflecting device and the screen and is corrected according to the tangent condition so as to be free of distortion. The transformation optical system has at least two optical stages. The first optical stage produces an intermediate image plane which is imaged on the screen by means of the subsequent optical stage (s).

Abstract: A projector device, which is simple and small and able to display images brighter and also able to improve the usefulness considerably. The effective reflecting lights of the mirror deflection type light modulators are focused into images at the position right in front of the projection lens, and the effective reflection lights are partly turned and focused on the two-dimensional position detector means for detecting the vertical and horizontal positions of the formed images.

Abstract: A projection display apparatus having three projection tubes for the projection of images of different primary colors wherein the images from the projection tubes are projected on an enlarged scale onto a screen through projection lenses. The display apparatus includes a first deflection unit having at least a first deflection coil mounted on a neck portion of a first projection tube, a second deflection unit having at least a second deflection coil mounted on a neck portion of a second projection tube and a third deflection unit having at least a third deflection coil mounted on a neck portion of a third projection tube. According to a feature of the display apparatus, a first linearity correction coil is coupled in series with a parallel connection of the second deflection unit and only one of the first and third deflection units.

Abstract: The present invention relates to a video system for entertainment and game apparatus. The video system includes a data carrier on which the game is stored. Video informations (pictures) stored on the data carrier are displayed on a display unit. By a lens and projection system the picture is imaged on a curved projection screen that at least partially surrounds the player. Preferably, the video informations are stored on the data carrier in pre-equalized form so that the image projected on the projection screen is essentially free of distortion.

Abstract: In a television receiver, having the ability to display differing image formats, the image width is capable of being continuously adjustable in the manner of a zoom effect. The ability to continuously adjust the image width is accomplished without any perceptible effect on the horizontal scan output. In that circuit, a tangent capacitor is coupled to a second capacitor with a switch being connected for switching the second capacitor into and out of the circuit. The switch is closed for an adjustable period beginning at the line center.

Abstract: The television apparatus of the present invention is an apparatus which displays an image corresponding to the television signal, is so arranged that the picture quality of an image signal can be adjusted according to the projection condition of the image when the image corresponding to the image signal is projected, so that the optimum image may be projected.

Abstract: An image projection system which comprises a light source, a color separating optical means for separating rays of light from the light source into blue, green and red light components, first to third liquid crystal panels each having an image forming center and being operable to modulate the associated light component in response to a video signal applied thereto thereby to form an image in a corresponding color, first to third projection lens assemblies associated with the first to third liquid crystal panels for projecting imagewise modulated light components, carrying the images formed respectively by the first to third liquid crystal panels, onto a screen in a superimposed fashion to provide a color picture. The first and third liquid crystal panels are positioned on respective sides of the second light valve and also positioned with their image forming centers displaced relative to the associated optical axes of the first and third projection lens assemblies.