63fb46d6_bster_US___Patent_applications__Description
[Patent application number] 20130235395 [Published] 09-12-2013 [Description] 
INTEGRATED COLOR DETECTION AND COLOR PIXEL COUNTING FOR BILLING - Disclosed herein are a method and an image processing apparatus implementing the method for color pixel counting in documents by integrating color detection and counting. The method determines if pixels are neutral (e.g., gray) or non-neutral (i.e., color). Windows are used to analyze the pixels. For each window, a number of pixels with at least one color plane ON are counted, as well as a number of ON pixels in each color plane. The windows are determined to be neutral or color. A billable count of color pixels is determined based on the neutrality of the windows. Based on the billable count of color pixels, a bill for outputting the document is determined.
Xing Li, Webster US - Patent applications