63fb46d6_bster_US___Patent_applications__Description
[Patent application number] 20090195801 [Published] 08-06-2009 [Description] 
ESTIMATING AN AMOUNT OF COLOR CONTENT IN A DOCUMENT - What is provided herein is a novel system and method for estimating the amount of color in a document. In one embodiment, a binary CMYK input image is received. Each of the CMYK plane is received at an offset from the previous plane, i.e., the 4 planes are not received simultaneously. Each plane is divided into M×N tiles. Pixel values of all four planes are examined separately and the number of on-pixels is counted for each plane. The number of on-pixel counts for each tile are aggregated for each plane. Total on-pixel counts are used to estimate the total number of white, black, color, and gray pixel counts. The total counts for all planes are used to estimate the amount of color. A document is determined to be color if the amount of color exceeds a predetermined threshold. A color billing strategy is determined based on the estimated color amount.
Xing Li, Webster US - Patent applications