4. The method of claim 3 wherein a degree of the shade of black or the shade of grey is based on a shade of the second most frequently occurring color of the plurality of colors, or a shade of the third most frequently occurring color of the plurality of colors.
3. The method of claim 1 further comprising filtering out pixels of the plurality of pixels from the electronic document image if the color of the pixels of the plurality of pixels substantially comprises a shade of black or a shade of grey.