1. A method for detecting edge pixels in an image plane based on intensity and neutrality of a current pixel, when separating an image signal into a set of image planes, the method comprising: searching, via a min-max module, for a minimum value and a maximum value of a specified characteristic within at least one predefined neighborhood pixel window centered on the current pixel in the image signal, wherein the predefined neighborhood pixel window comprises the edge pixels; and detecting, via a dynamic threshold module, the edge pixels in the image plane based on predetermined criteria, wherein the predetermined criteria for detecting the edge pixels comprises determining whether: (a) a difference between the maximum value and the minimum value of the specified characteristic is greater than or equal to a predetermined threshold, wherein the predetermined threshold is based on the intensity and the neutrality of the current pixel in the image signal; and (b) (i) a difference between a current value and the minimum value of the specified characteristic, or (ii) a difference between a current value and the maximum value of the specified characteristic is greater than or equal to a predetermined threshold, wherein the predetermined threshold is based on the intensity and the neutrality of the current pixel in the image signal.