1. A process, comprising: determining displacement of an entity equipped with a sensor for capturing a sequence of images, by, determining dimensions of a correlation block of pixels in a current image in the sequence of images as a function of a motion vector associated with an image preceding the current image in the sequence of images; and determining a motion vector associated with the current image in the sequences of images as a function of at least one correlation calculated between the correlation block of pixels in the current image and a second block of pixels from which the vector points towards said correlation block of pixels, with the second block being in a previous image in the sequence of images, wherein a size of the correlation block is a decreasing function of the motion vector associated with the previous image in the sequence of images.