1. Method of detecting the reliability of a field of movement vectors of one image in a sequence of video images, characterized in that it includes a stage of calculating a stability parameter Det_Stab(t) for the field, on the basis of a comparison ( 4 ), over two successive images, of the number of occurrences of the majority vectors of the movement-vectors fields of each of these images, a field being defined as stable if the variation in the number of occurrences lies within a predefined bracket, and a stage of deciding on reliability ( 7 ) on the basis of this stability parameter.