1. An image interpolating method comprising: detecting an edge direction by calculating absolute inter-channel differences with respect to left, right, up, and down directions of a central pixel of a color filter array according to pattern characteristics of R, G, and B pixels arranged in the color filter array; calculating directional interpolation weights for the left, right, up, and down directions, respectively, according to the pattern characteristics of the R, G, and B pixels; and interpolating an unknown pixel value using color differences between the R, G, and B pixels with respect to the left, right, up, and down directions of the center pixel and the directional interpolation weights according to the detected edge direction.