1. Process for smoothing dark regions of an image sequence having undergone temporal filtering, a noise level (&sgr;) being associated with each image, a luminance value being associated with each pixel of an image, characterized in that, at least one predetermined so-called threshold value (S1,S2) is calculated as a function of the noise level of the image and the zero value is added to the calculated values, at least two predetermined values (Cst i, Cst i&plus;1) are defined which delimit at least one smoothing range, for each pixel of the image, the pixel currently being analysed being referred to as the current pixel (P), the luminance of the said pixel is compared (E 1,F 1,F 6,G 1 ) with the said predetermined values (Cst i, Cst i&plus;1) delimiting at least one smoothing range, if the luminance of the current pixel (P) lies in one of the said smoothing ranges, the luminance of a plurality (K) of pixels, the so-called analysis pixels, in a neighbourhood window, the so-called analysis window (FA), centred on the current pixel (P), is compared (E 2,E 3,F 2,F 3,F 7,F 8,G 2,G 3 ) with the said values delimiting at least one smoothing range, if the luminance of at least a predetermined minimum number (n) of analysis pixels lies in the same range as the value of the luminance of the current pixel, the value of the luminance (V(P)) of the current pixel (P) is modified (E 4,F 4,F 9,G 6,F 7 ) as a function of the said threshold values (0,S1,S2).