The present invention relates to apparatus for separately extracting circular and linear components in a complex image, the apparatus comprising: (a) a circular filter means for covering a portion of the complex image by filter blocks, wherein the filter blocks comprise a center block and at least one set of blocks angularly disposed to encircle the center block; (b) a first calculator element for computing average image concentration value for each of a plurality of directions with said circular filter means covering a subject portion of the complex image, wherein the concentration value for one directional component is a maximum; (c) a second calculator element for computing a first feature S in which the values of the directional components are evaluated with maximum directional component being enhanced; (d) a third calculator element for computing a second feature value S' in which the values of the directional components are evaluated with the maximum directional component being weakened; and (e) a mode selector for selectively applying (i) the first feature value S to detect linear image components and (ii) the second feature value S' to detect circular image components.