1. An image processing method in an image processing apparatus, the method comprising: setting, by the image processing apparatus, a window within an input image; analyzing the window to determine edges of objects within an image included in the window; calculating a value of directional projection of each direction of the window; calculating values of the directional projections exhibiting a maximum difference among differences between the values of the directional projections obtained based on the directions of the window; detecting directions of the edges using the values of the directional projections exhibiting the maximum difference; generating edge information including the edge directions; and processing and outputting the window using the edge information.