Abstract: While traditional linear and non-linear filters reduce the noise in images,some important details are unavoidably lost,especially linear structures such as curves and edges.Morphological extension is a valid measurement mechanism to distinguish noise and detail information.Different structure features can be expressed by measuring their morphological extension.Non-linear filters based on mathematical morphology have validly and are widely applied in the field of image filtering.After analyzing the limitations of traditional morphological filters,this paper proposes a new CS morphological filtering model,based on contour-structuring elements,for measuring the morphological extension of connected components in images.A morphological hit operation based on contour- structuring elements is defined.Using the hit operation,the proposed CS morphological filter can extract a noise-area and clear all noises in the noise-area at once.Experimental results indicate that this method has satifactory noise-resistance characteristics and excellent performance for image detail preservation.