1. A method of detecting the location and luminance transition range of a slant image edge in a digital image comprising pixels, the method comprising the steps of: (a) defining a two-dimensional window in the digital image; (b) determining a variance value for a plurality of pixels around a selected pixel inside the window; (c) based on the variance value, determining if the selected pixel is in an edge region; (d) if the selected pixel is in an edge region, then generating a binary pattern for the pixels in the window based on the mean value of at least said plurality of pixels in the window, the binary pattern comprising binary values corresponding to the pixel values; (e) based on the binary pattern data, determining if the selected pixel is essentially a center pixel in a luminance transition range of a slant edge; and (f) if the selected pixel is essentially a center pixel in a luminance transition range of a slant edge, then determining the length of the luminance transition range of the slant image edge.