1. A method for expanding and enhancing input digital image data having an input coordinate space, and producing output digital image data having an output coordinate space with certain resolution and shape, by applying adaptive edge interpolation to an output pixel, said method comprising: (a) obtaining the input digital image data; (b) mapping the output pixel coordinates onto the input coordinate space obtained in (a); (c) selecting a block of M×N input pixels around the mapped point of (b) wherein the shape and size of said block is determined based on a required edge resolution; (d) applying horizontal and vertical lowpass filters to the input pixels of said block to reduce noise, and downsample to change the scale to adjust the aspect ratio, and to adapt to low angle edge detection; (e) computing local signal variance for each downsampled pixel of (d) in said block to determine signal behavior; (f) computing average signal variance, based on local signal variances determined in (e) in said block, to determine average signal behavior in the block; (g) determining orientation, anisotropy, and strength of an edge based on the average signal variance found in (f); (h) determining frequency response of resampling filter and its footprint in the input image at the mapped position determined in (b), based on orientation, anisotropy, and strength of the edge determined in (g); and (i) determining the value of the output pixel via resampling in the footprint found in (h) according to the frequency response of (h).