1. A processor-implemented method for color pixel counting in documents for billing comprising at least one page using an image processing apparatus, the image processing apparatus comprising at least one processor for processing documents containing image data comprising a plurality of pixels, the method comprising the following acts implemented by the at least one processor: receiving image data of a document comprising a plurality of pixels; determining a billable count of color pixels in the received image data by establishing windows in the image data comprising M rows and N columns of pixels, and, for each window: calculating an area coverage of color pixels by (a) counting a first count of color pixels, the counting of the first count comprising counting each color pixel in the window once, wherein each pixel has at least one color plane ON; performing color detection by (b) counting, for each separate color plane in the window, a second count of color pixels, the counting of the second count comprising individually counting a number of ON pixels in that color plane; a total of the second counts of color pixels being different than the first count of color pixels for the window; determining if the window is color or neutral based on at least the second counts, and if the window is determined as color, adding the first count to the billable count of color pixels, else, adding the first count to a neutral pixel count.