Patent ID: 8111332

Claim:
A method of suppressing noise of an input video signal and outputting an output video signal, the method comprising: generating a difference signal being a field difference or a frame difference between the input video signal and the output video signal; generating a noise compensation signal by multiplying the difference signal by a feedback ratio; subtracting the noise compensation signal from the input video signal; and controlling a feedback ratio, wherein the controlling of a feedback ratio includes: determining a signal level of the difference signal by a criterion value for each area set for the difference signal, detecting an abrupt change in a signal level of the input video signal, counting the number of fields or the number of frames of the input video signal from the time when a first abrupt change in the signal level is detected to the time when a second abrupt change in the signal level is subsequently detected, and setting a feedback ratio for each of the areas in accordance with a count value resulting from the counting, wherein the feedback ratio is set such that the feedback ratio gradually increases from 0 as the count value increases.