1. A method of amplifying temporal variation in at least two images, the method comprising: for each particular pixel of the at least two images, detecting a temporal variation of the particular pixel of the at least two images by applying a bandpass filter configured to analyze frequencies over time, the resulting detected temporal variation of the particular pixel between the two images being below a particular threshold; and amplifying the detected temporal variation of each particular pixel; and providing at least two modulated images by adding the amplified temporal variation to the at least two images by synthesizing the modulated images, for an amplification factor α, according to ƒ(x+(1+α)δ(t)), δ(t) being a displacement function.