This paper presents a new algorithm for image registration working on an image sequence using dominant corners located on the image's edges under the assumption that the deformation between the successive images can be modeled by an affine transformation. To guarantee this assumption, the time interval between acquired images should be small like the time interval in a video sequence. In the edge image, dominant corners are extracted per linked contour and form a polygon that best approximates the current linked contour. The number of these dominant corners per contour is derived automatically given an approximation error. These dominant corners are shown to be very repeatable under affinity transformation. Then, a Primitive is constructed by four dominant corners. The invariant measure that characterizes each primitive is the ratio of areas of two triangles constructed by two triplets selected from these four corners.