Patent ID: 6707503
Filing Date: 2004-03-16
Classification: G09G,H03L,H04N

Abstract:
A video signal processing device for sampling digital video signals representing an image at a timing based on sampling clocks, and processing the sampled video signal data, including:switching means or switching inputs between said video signal and test signals including a white level signal of a first predetermined level being lower than the displayable maximum level and a black level signal of a second predetermined level being higher than the displayable minimum level, sampling means for sampling either one of said video signal and said test signals at the timing based on the sampling clocks, classification means for classifying, when sampling said test signals, data of the sampled test signals into a high-level picture element data group of a first value range including said first predetermined level data and a low-level picture-element data group of a second value range including said second predetermined level data, a level of the second value range being lower than said first value range, calculation means for calculating statistics which are based on the variance of values of picture element data in said high-level picture-element data group and the variance of the values of picture element data in said low-level picture-element data group; adjustment means for adjusting the phase of the sampling clocks on the basis of the successively calculated statistics so that the variance of the value of the picture element data in the high-level picture element data group and the variance of the values of the picture element data in the low-level picture element data group are reduced; storage means for storing a phase setting value adjusted by said adjustment means in a non-volatile storage device, and control means, when sampling of said video signal, for reading out said phase setting value from said storage means and sampling said video signal by the sampling clock adjusted with said phase setting value to store the video signal into an image memory.