1. A method for improving image quality of edge pixels in a background plane, 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 a current pixel in the image signal, wherein the predefined neighborhood pixel window comprises the edge pixels; and conditionally switching, via a dynamic threshold module, the edge pixels to either the respective minimum value of the specified characteristic or the maximum value of the specified characteristic received from the min-max module, or to a value of the specified characteristic of the current pixel, based on a predetermined criteria, wherein the predetermined criteria for conditionally switching the edge pixels comprises determining whether a maximum luminance value in the predefined neighborhood pixel window is greater than or equal to a predetermined threshold.