Method and apparatus for reducing visibility of damping wires in aperture grill display tubes

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.

What is claimed is:  
     
       1. Apparatus for reducing the visibility of the shadow cast by a damping wire on the screen of a display device, comprising: 
       a sensor device for locating said shadow on said screen of said display device and responsively generate amplitude values of the area of said screen immediately adjacent said shadow;  
       a processor for receiving said generated amplitude values and responsively calculating correction values; and  
       a compensator device coupled to said processor for utilizing said correction values for reducing the visibility of said shadow on said screen.  
     
     
       2. The apparatus of  claim 1  wherein a compensation engine program controls said processor. 
     
     
       3. The apparatus of  claim 1  wherein said correction values are converted into video values which are alternately and sequentially stored in a plurality of display lists along with corresponding location addresses. 
     
     
       4. Apparatus for correcting artifacts on the screen of a display device, comprising: 
       a sensor device for locating said artifacts on said screen and responsively generating amplitude values of the area of said screen immediately adjacent said artifacts, wherein said artifacts may include at least one damping wire shadow that is visible on said screen,  
       a processor for receiving said generated amplitude values and responsively calculating correction values, said correction values being converted into video values which are alternately and sequentially stored in a plurality of display lists along with corresponding location addresses; and  
       a compensator device coupled to said processor for utilizing said correction values for reducing the visibility of said artifacts on said screen of said display device, said display device comprising a cathode ray tube.  
     
     
       5. The apparatus of  claim 4  wherein a shadow is located by illuminating successive scan rows on said screen of said cathode ray tube and then detecting the scan row having a least amplitude value. 
     
     
       6. The apparatus of  claim 5  wherein said correction values are calculated by subtracting said least amplitude value from an average of two of said amplitude values from said scan rows immediately adjacent to the scan row affected by said damping wire shadow. 
     
     
       7. The apparatus of  claim 4  wherein said compensator device converts said video values to analog voltages and then applies said analog voltages to video amplifiers driving said cathode ray tube. 
     
     
       8. The apparatus of  claim 1  wherein said amplitude values are processed with a differentiation routine to locate said shadow on said screen of said display device, said display device comprising a cathode ray tube. 
     
     
       9. A method for reducing the visibility of the shadow cast by a damping wire on the screen of a display device comprising the steps of: 
       using a sensor device to locate said shadow on the screen of said display device and responsively generate amplitude values of the area of said screen immediately adjacent said shadow;  
       calculating correction values from said generated amplitude values using a processor; and  
       utilizing said correction values to reduce the effects of the visibility of said shadow on the screen of said display device by using a compensator device coupled to said processor.  
     
     
       10. The method of  claim 9  wherein a compensation engine program controls said processor. 
     
     
       11. The method of  claim 9  wherein said correction values are converted into video values which are alternately and sequentially stored in a plurality of display lists along with corresponding location addresses. 
     
     
       12. A method for correcting artifacts on the screen of a display device comprising the steps of: 
       using a sensor device to locate said artifacts on the screen of said display device and responsively generate amplitude values of the area of said screen immediately adjacent said artifacts, wherein said artifacts may include at least one damping wire shadow that is visible on the screen of said display device;  
       calculating correction values from said generated amplitude values using a processor, said correction values being converted into video values which are alternately and sequentially stored in a plurality of display lists along with corresponding location addresses; and  
       utilizing said correction values to reduce the effects of the visibility of said artifacts on the screen of said display device by using a compensator device coupled to said processor, said display device comprising a cathode ray tube.  
     
     
       13. The method of  claim 12  wherein a shadow is located by illuminating successive scan rows on the screen of said display device and then responsively detecting and locating the scan row having the smallest one of said amplitude values. 
     
     
       14. The method of  claim 13  wherein said correction values are calculated by subtracting said least amplitude value from an average of two of said amplitude values from the scan rows immediately adjacent to the scan row affected by said damping wire shadow. 
     
     
       15. The method of  claim 12  wherein said compensator device converts said correction values to analog voltages and then applies said analog voltages to video amplifiers driving said display device. 
     
     
       16. The method of  claim 9  wherein said amplitude values are processed with a differentiation routine to locate said shadow on said screen, and said display device comprises a cathode ray tube. 
     
     
       17. A computer-readable medium comprising program instructions for reducing the visibility of the shadow cast by a damping wire on the screen of a display device by performing the steps of: 
       using a sensor device to locate said shadow on said screen of said display device and responsively generate amplitude values of the area of said screen immediately adjacent said shadow;  
       calculating correction values from said generated amplitude values using a processor; and  
       utilizing said correction values to reduce the visibility of said shadow on said screen of said display device by using a compensator device coupled to said processor.  
     
     
       18. A computer-readable medium comprising program instructions for correcting artifacts on the screen of a display device by performing the steps of: 
       using a sensor device to locate said artifacts on said screen of said display device and responsively generate amplitude values of the area of said screen immediately adjacent said artifacts, wherein said artifacts may include at least one damping wire shadow that is visible on the screen of said display device;  
       calculating correction values from said generated amplitude values using a processor; and  
       utilizing said correction values to reduce the visibility of said artifacts on said screen of said display device by using a compensator device coupled to said processor, said display device comprising a cathode ray tube.  
     
     
       19. The computer-readable medium of  claim 18  wherein a shadow is located by illuminating successive scan rows on the screen of said display device and responsively detecting and locating the scan row having the smallest one of said amplitude values. 
     
     
       20. Apparatus for reducing the visibility of the shadow caused by a damping wire on the screen of a display device, comprising: 
       means for using a sensor device to locate said shadow on the screen of said display device and responsively generate amplitude values of the area of said screen immediately adjacent said shadow;  
       means for calculating correction values from said generated amplitude values using a processor; and  
       means for utilizing said correction values to reduce the visibility of said shadow on the screen of said display device by using a compensator device coupled to said processor.  
     
     
       21. An apparatus for reducing the visibility of a shadow cast by a damping wire on a screen of a display device, comprising: 
       
         a control module for providing a first address corresponding to a current location of an electronic beam in the display device;  
       
       
         a memory for storing a display list including a correction value and address corresponding to a predetermined location on the screen associated with the shadow; and  
       
       
         a comparing module for comparing the first and second addresses, and responsive to a match, utilizing the correction value for reducing the visibility of the shadow on the screen. 
       
     
     
       22. The apparatus of  claim 21 , wherein the correction value represents the amount of adjustment needed to compensate for the shadow. 
     
     
       23. The apparatus of  claim 21 , wherein the display list comprises first and second lists having sequences of correction values, which are alternately utilized for reducing the visibility of the shadow on the screen. 
     
     
       24. The apparatus of  claim 21 , wherein the correction value is used to generate a correction signal, which is provided to a gain modulation input of a video amplifier for reducing the visibility of the shadow on the screen. 
     
     
       25. The apparatus of  claim 24 , wherein the correction signal is applied to gain modulation inputs of Red, Green Blue video amplifiers for reducing the visibility of the shadow on the screen. 
     
     
       26. The apparatus of  claim 24 , wherein the correction signal is generated by manually guiding the placement of compensation on the screen using a cursor control device. 
     
     
       27. The apparatus of  claim 21 , wherein the correction value is indicative of the amount of adjustment needed to compensate for the shadow. 
     
     
       28. The apparatus of  claim 21 , wherein the second address is adjusted by adding or subtracting counts proportional to the intensity of the ambient magnetic fields in the display device. 
     
     
       29. The apparatus of  claim 21 , wherein the correction value is adjusted to track a change in raster size and position by monitoring deflection current and voltage.