In view of the selection of structure elements problem in morphological filter,this paper presents morphological operators with non-fixed shape and non-fixed size kernels,or amoebas,instead of fixed-shape,fixed size structuring elements generally used.These structure kernels take into account the image contour variations to adapt their shape and size according to the gradient criteria built firstly.Then,it performs the median or mean filtering at each pixel with these structure kernels.Experiments results show that this method can simultaneously suppress the clutter and enhance edges to overcome the transitional filter′s drawbacks,simultaneously comparing the anisotropic filter has better efficiency.