1. An illuminant estimation method, comprising: detecting, using at least one processing device, a plurality of valid images out of data of a plurality of input images so that each valid image is a respective current image whose calculated difference from a respective previous image is determined, in the detecting of the plurality of valid images, to meet a respective minimum threshold; and determining and outputting an illuminant for white balancing of at least one image of the plurality of images based on at least one estimated illuminant obtained based on respective comparisons of calculated variance indicators of one or more of the detected valid images, after the detection of the valid images.