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

Abstract: By providing a plurality of landing correction coil pairs each comprised of a correction coil in the x-axis direction and a correction coil in the y-axis direction at four peripheral corner portions of the cathode ray tube (CRT) and by controlling the direction and magnitude of the resultant vector of the correction magnetic fields generated by the x-axis direction correction coil and the y-axis direction correction coil, the influence of the geomagnetism is canceled to allow a high-accuracy landing correction to be achieved. Furthermore, by detecting the chromaticity and luminance information on the screen to obtain a mislanding quantity and by forming a correction current corresponding to the quantity through the aforementioned correction means to perform an automatic correction to allow a quantitative landing correction to be performed correctly in a short time.

Abstract: An apparatus for correcting images includes: a test signal generator for generating a test signal; a display device for displaying the test signal in a region on a display screen; an imaging device for imaging the test signal displayed on the display screen in a scanning direction so as to produce an image signal having a rising linear portion and a falling linear portion along the scanning direction; a position calculator for calculating a position of a centroid of the image signal for each of R, G and B colors, based on the rising linear portion and the falling linear portion; an error detector for detecting an amount of error between the detected positions of the centroids for R, G and B colors; a correction circuit for correcting a convergence and a geometric distortion for the region, based on the amount of error.

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

Abstract: A convergence correction apparatus comprises: a scanning waveform generating section (6) for generating a scanning waveform in synchronization with a sync signal for scanning an electron beam in a cathode ray tube (8); an amplitude control section (7) for controlling a raster size according to a scanning waveform generated by the scanning waveform generating means (6) with receipt of a control signal; and a convergence correction waveform generating section (5) for generating a correction waveform for performing a convergence correction according to the scanning waveform and the control signal. Therefore, the apparatus can automatically follow signal sources having different input scanning frequencies and different aspect ratios thereby to obviate the need for complicated adjustment in each mode and remarkably reducing the time necessary for the adjustment.

Abstract: A cathode ray tube control apparatus includes phosphor display screen, three electron guns for emitting R, G, B electron beams to the display screen, a shadow mask placed between the electron guns and the display screen, and index phosphors deposited on the shadow mask and having at least two line elements diagonal to a horizontal scanning direction of the electron beam for generating a signal according to the electron beam scan. Further provided are detector for detecting beam crossing points over the index phosphor, and correction circuit for correcting the deflection of the electron beam based on the detected beam crossing points.

Abstract: A signal generating apparatus comprises: a scanning-line number detector (2) for detecting the number of scanning lines with receipt of a sync signal; a convergence memory (3) for storing convergence correction data; an on-screen display memory (5) for storing on-screen display data; an interpolator (4) for performing vertical interpolation of output data derived from the memories (3, 5) according to the detection signal derived from the scanning-line number detector (2); and a frame memory (6) for successively reading data elements corresponding to the individual scanning lines interpolated by the interpolator (4). The apparatus detects the number of scanning lines and generates a correction signal and a character signal through vertical processing of convergence correction data and on-screen character data.

Abstract: A digital convergence apparatus detects the presence/absence, frequency and the number of scanning lines of inputted synchronizing signals, performs an interpolation between adjusting points corresponding to the detection signal to prepare a correction data, and performs a cursor display of a center position between adjusting points, extrapolating operation control and difference data storage, writing of the same data into n-planes, and time sharing the interpolation processor so as to accommodate multimedia with a high accuracy.

Abstract: An image correction apparatus uses digital correction data from a memory device, in which various correction data is stored, and various analog correction waveforms for implementing, through digital control, various correction, such as convergence, deflection, luminance, focus, frame phase, etc., to thereby accomplishing accurate and automatic correction.

Abstract: A digital convergence apparatus detects the presence/absence, frequency and the number of scanning lines of inputted synchronizing signals, performs an interpolation between adjusting points corresponding to the detection signal to prepare a correction data, and performs a cursor display of a center position between adjusting points, extrapolating operation control and difference data storage, writing of the same data into n-planes, and time sharing of the interpolation processor so as to accommodate multimedia with a high accuracy.

Abstract: An image correction apparatus in which adjustment of a projector unit for widening projection with a plurality of projector tubes can be eliminated by setting specifications of the projecting optical system and by automatically calculating converging angles at which images of light of respective colors are formed on a screen, so as to automatically compute various correction data for geometrical distortion, luminance reduction and focus error.

Abstract: A digital convergence unit detects the aspect ratio of the screen and converts stored convergence correction data in accordance with the detected signal. This can be achieved with high precision and with a small memory capacity. It can also be applied to multimedia by data processing suitable for each scanning frequency.

Abstract: An automatic primary color component covergence alignment system for a color television display apparatus is presented whereby an alignment pattern is periodically displayed in peripheral regions of the television screen, in each of the primary colors during respective successive correction intervals, the pattern positioned such as to fall upon photo-sensitive devices disposed at the screen periphery. Adjustment of pattern position is executed during each correction interval, based on position data derived from output signals from the photo-sensitive devices, such as to align the alignment pattern with predetermined reference positions. During each period between these sets of correction intervals, the position data thus derived are held stored and are continuously utilized for controlling the deflection of respective electron beams used in generating the primary colors, to thereby implement automatic convergence alignment adjustment.

Abstract: A system for compensating image contour by modulating a scanning velocity in accordance with a video signal is disclosed, in which a mean current dissipated in a driving power amplifier is detected to control a gain of an amplifier in a preceding stage for suppressing the increase of power dissipation in the power amplifier when a video signal having many noises is received. The preceding stage amplifier is provided with a saturation characteristic to enhance the effect of contour compensation at a small amplitude signal and eliminate over compensation of image contour at a large amplitude signal. The combination of the saturation characteristic and the gain control further enhances the effect of suppression of power dissipation.