Patent ID: 7855806

Claim:
A method comprising: printing by a marking device and imaging test targets over multiple sampling intervals; obtaining by a timer module timing information utilizing criteria including a defect, a start of an imaged page, and a page sync, wherein the obtaining includes estimating at least a time elapsed between the defect and the start of the imaged page for placing each test target relative to a banding source having a banding defect period; obtaining by an image sensor print profiles corresponding to an average pixel value of an image matrix by: determining a defect once around signal time period of a defect source inherent in the marking device, the defect source resulting in one or more banding defect frequencies; determining a reference scanline time delay which is a time between a page sync signal and a writing of a reference scanline; determining a defect time delay which is a time between a reference point on the defect source and a page sync signal; and determining a page sync time delay for each sampling interval which is a time between successive page sync signals for each sampling interval; and combining by a digital signal processing module the timing information with the print profiles to obtain an estimate of the banding defect.