Patent ID: 7639285

Claim:
A flicker-reduction method for reducing a flicker component of a fluorescent lamp, the method comprising: a capturing step of capturing an input video signal from light passing through a lens of a camera onto an imaging element of the camera, the input video signal being of a subject under lighting of the fluorescent lamp; and performing, by a digital signal processor of the camera: an integration step of integrating the input video signal of the subject, shot over a time period greater than a horizontal period; a normalization step of normalizing an integral value obtained in the integration step or the difference value between integral values of adjacent fields or frames; an extraction step of extracting the spectrum of the integral value or the difference value normalized in the normalization step; an estimation step of estimating the flicker component from the spectrum extracted in the extraction step; a subtraction step of acquiring the current integral value obtained by integrating the input video signal over a time period greater than a horizontal period and the integral value of a field preceding the current field by several fields and determining the difference of the integral values; a computation step of computing the probability of being under the lighting of a fluorescent lamp from the difference of the integral values determined in the subtraction step; a flicker-reduction signal generation step of generating a flicker-reduction signal for canceling the flicker component estimated in the estimation step according to the probability of being under the lighting of a fluorescent lamp as computed from the difference of the integral values; and an arithmetic operation step of subjecting the flicker-reduction signal generated in the flicker-reduction signal generation step and the input video signal to an arithmetic operation.