63fb46d6_bster_US___Patent_applications__Description
[Patent application number] 20150085320 [Published] 03-26-2015 [Description] 
IMAGE PROCESSING BASED ON AUTOMATIC IMAGE-TYPE DETECTION - Methods and systems divide an image into image blocks, determine a number of high-variation blocks within valid image blocks, determine a page variance measure by dividing the number of high-variation blocks by the total number of valid image blocks, and classify the image as comprising a halftone and/or text image if the page variance measure exceeds a halftone threshold. Such methods and systems classify the image as being a continuous tone image if the page variance measure does not exceed the halftone threshold and a text index is below a text index threshold, and classify the image as being a continuous tone and text image if the page variance measure does not exceed the halftone threshold and the text index is not below the text index threshold. Further, such methods and systems select an image processing mode based on such image classifications.
Xing Li, Webster US - Patent applications