1. A method for magnifying image by an interpolation based on an edge and a corner, the method comprising the steps of: a) setting m×m local windows excluding outer boundaries of an original image, when the original image inputted for image enlargement by arbitrary magnification, and calculating a direction of each m×m local window; b) when a linear direction exists in an m×m local window, considering an edge exists in the m×m local window; c) when a linear direction does not exist in the m×m local window, dividing the m×m local window into m/2×m/2 sub windows and calculating directions of the m/2×m/2 sub windows; d) when the directions of the m/2×m/2 sub windows exists toward the center of the m×m local window, considering a corner exists in the m×m local window; and e) selecting pixels located in a virtual line that goes along in the linear direction or in the directions to calculate a new pixel value by using the pixels, each having different weight according to intensity of the direction for the existing edge and corner.