The present invention discloses an image processing apparatus for processing an image. The image processing apparatus includes a line-pattern detecting module and an image processing module. The line-pattern detecting module examines how a first plurality of pixels of a first pixel line change and how a second plurality of pixels of a second pixel line change so as to determine which pattern an area of the image corresponds to. The image processing module selectively performs at least one of a plurality of image processing operations according to the pattern the image area corresponds to. The first and the second pixel lines correspond to the image area.