Digital image correction device

Claim 1

An image correction device for use in an image display device including a display mode selector for selecting one of a plurality of different display modes and operable in any of the different display modes, comprising: address generating means for generating address corresponding to positions on an image screen of said display device in synchronism with an input video signal; regulation pattern generating means for generating, in synchronism with said input video signal, a regulation pattern for regulating positions of regulation points selected from correction points on said image screen; first storing means for storing correction data of the correction points in address generated by said address generating means; digital to analog converter means for converting a digital signal read out from said first storing means into an analog signal; responsive means responsive to the analog signal for regulating parameters of a display tube of said display device; deflection current detecting means for detecting deflection current flowing through deflection coils of said display device; second storing means for storing the correction data and deflection currents detected by said deflection current detecting means in a reference display mode; correction data generating means for generating the correction data of the correction points in a certain display mode other than the reference display mode by interpolation based on the content of said second storing means and deflection currents re-detected in the certain display mode by said deflection current detecting means and supplying the generated correction data to said first storing means; and central processing means for controlling an operation of said image correction device.

Claim 18

A method of correcting convergence of a display device having a plurality of display modes different in raster size and signal specification from each other, said method comprising the steps of: a) selecting a reference display mode; b) regulating convergence in the reference mode to obtain convergence correction data of each of regulation points selected from a plurality of correction points on an image screen of said display device; c) obtaining convergence correction data of each of said correction points by interpolation utilizing time as a variable on the basis of convergence correction data of the regulation points; d) detecting deflection currents corresponding to said regulation points; e) storing the convergence correction data of correction points in first storing means; f) storing deflection currents at respective regulation points in said first storing means; g) switching the corrected display mode from reference mode to a second display mode; h) detecting deflection currents at respective regulation points in the second display mode; i) obtaining convergence correction data of the respective regulation points by interpolation utilizing the correlation between convergence correction data of the regulation points and deflection currents in the reference mode; j) on the basis of thus obtained convergence correction data of the regulation points, obtaining convergence correction data of respective correction points by time interpolation in the same manner as in the reference mode and storing the convergence correction data in second storing means; and k) correcting an image on said image screen on the basis of the content of said random access memory.