Patent ID: 7450135

Claim:
A method of detecting an abnormal video signal in a display device of a computer system, comprising: receiving an R,G,B signal including a video signal, a horizontal synchronization signal and a vertical synchronization signal from a host of the computer system; selecting one of an R, a G, or a B component of the R,G,B signal including the video signal as a selected one R,G, or B component and setting a region of the selected one R,G, or B component as a checked region which is checked; detecting a minimum pixel level value in the checked region; comparing the minimum pixel level value for the selected one R,G, or B component with a predetermined threshold value to determine whether an abnormal R,G, or B component is present, the abnormal R,G, or B component being a component abnormally input due to malfunction of the host; and displaying on a screen a message indicating whether the selected one R,G, or B component includes a video signal abnormally input due to the malfunction of the host.