Patent ID: 6097444
Filing Date: 2000-08-01
Classification: G09G,H04N

Abstract:
A device for automatically adjusting image quality, comprising:(a) frequency optimizing means for generating a frequency control signal for setting a frequency of a sampling clock signal synchronous with a synchronizing signal provided from the exterior;(b) phase optimizing means for generating a phase control signal for setting a phase of said sampling clock signal;(c) clock producing means receiving said synchronizing signal, said frequency control signal and said phase control signal for generating said sampling clock signal having said frequency determined by said frequency control signal and said phase determined by said phase control signal and synchronous with said synchronizing signal;(d) converting means receiving an analog video signal and said sampling clock signal for sampling and holding said analog video signal using timing of said sampling clock signal to convert said analog video signal into a digital video signal;(e) image quality detecting means receiving said digital video signal for detecting the quality of one picture indicated by said digital video signal to generate an image quality judgement data signal; and(f) storing means for storing said image quality judgement data signal outputted from said image quality detecting means and phase data indicative of said phase of said sampling clock signal associated with said image quality judgement data signal,said phase optimizing means comprising(b-1) phase control signal changing means for sequentially changing said phase indicated by said phase control signal by a predetermined amount of phase change from its initial value within a phase change range corresponding to one cycle of said sampling clock signal each time said storing means stores said image quality judgement data signal for said one picture and said phase data associated therewith, and(b-2) optimum phase determining means for extracting a maximum one of a group of data containing said image quality judgement data signal for said one picture stored in said storing means before the amount of change in said phase of said sampling clock signal reaches said phase change range to determine said phase of said sampling clock signal associated with said maximum one as an optimum phase and to finally determine an optimum phase control signal indicative of said optimum phase as said phase control signal.