1. A computer-implemented method for processing digital image data, the method comprising: obtaining digital data S(x,y,t,c) representing an image at a plurality of pixels (x,y) and a plurality of time values t for at least one color component c; processing the data S(x,y,t,c) to determine, for at least one pixel (x,y) and at least one time value t, an image value S*(x,y,t,c) as a function of a linear combination of the values S(x′,y′,t′,c) over a set A of points (x′,y′,t′) with plural values (x′,y′) and plural values t′, wherein each value S(x′,y′,t′,c) in the linear combination is multiplied by a coefficient which is a function of the difference S(x,y,t,c)−S′(x′,y′,t′,c), wherein for each (x′,y′,t′,c), the value S′(x′,y′,t′,c) is equal to either S(x,y,t,c) or S*(x′,y′,t′,c).