Alignment of cathode ray tube video displays using a host computer processor

Abstract

A system for automatically aligning video images on display devices such as cathode ray tube (CRT) monitors that use the processor and memory of a host computer to implement the alignment process. The system uses a host computer processor and previously generated correction factor data, representative of specific display distortion characteristics, to produce driver signals necessary to affect the alignment of video images on a CRT screen. The previously stored correction factor data may be retrieved from a characterization module within the display device or from any other convenient storage location. The correction factor data is processed by the host computer to produce correction control data which is transmitted, over a bi-directional serial connector, or a video connector, to the display device where the data is read by correction and driver circuitry. The specialized correction and driver circuitry set static decoders to generate the required correction signal for each distortion parameter at each location of the display screen. Correction factor data for dynamic distortion parameters may be stored in monitor memory where the data is used by waveform generators to produce dynamic correction signals. The plurality of correction signals are integrated, filtered, and summed by the CRT correction and driver circuitry before being applied to the CRT control circuits to align the video image. The present invention allows new correction signals to be quickly calculated by the host computer and applied to the CRT whenever a display parameter, such as resolution, frequency, color depth, etc. is changed. The host processor may generate the new data by using a gain matrix table, or interpolation techniques, as well as employing standard transformation equations.