Cross-scan investigation for closed circuit televison

Line structure resulting from the generation of a television raster is distracting in visual displays used for simulating real world scenes. The objective of this investigation was to seek a possible solution to the problem by means of utilizing cross-scan raster generation. It was hypothesized that the resulting grids would break up the solid straight line pattern and give a more uniform and less conspicuous appearance to the display. Additionally, an increase in picture information was expected due to the increased area scanned. Five different cross-scan schemes were investigated. While each method yielded an increase in area coverage and, therefore, an increase in picture information, sub-area flickering was a problem in all but one. It was concluded that the cross-scanning technique can produce a flicker-free raster with a more pleasing and somewhat less conspicuous pattern. To achieve any significant improvement in line structure appearance with the cross-scanning technique, it is necessary to start at double the scan number for any given standard scan number for which a comparison is to be made. As the scan number is increased, the bandwidth must also be increased and system noise becomes more of a problem. In light of these findings, it was further concluded that cross-scanning can provide an improvement at the lower scan numbers, but this improvement diminishes for the higher scan numbers.