Patent ID: 8571269

Claim:
A method for image quality defect detection on customer prints, the method comprising: receiving an image of a document printed using a color marking device intended to be analyzed for image quality defects; characterizing a resolving power of a sensor used to scan said image such that a deficiency of said resolving power can be determined; compensating for a resolving power deficiency of a sensor that generated said image, said compensating comprising: such that pixels in said image can be classified according to the colorants present at the corresponding location of said document determining a response of a de-blurring filter appropriate for compensating for said sensor's resolving power deficiency, said response being determined with respect to a Modulation Transfer Function (MTF) of said sensor; and applying an image enhancement to said image using said filter to obtain an enhanced image; classifying halftone dots on said enhanced image according to colorants present at a corresponding location of said image, said classification comprising: comparing a value for each pixel of said compensated image and a plurality of colorant combinations of said color marking device and, in response to said value being within a range of one of said colorant combinations, classifying said halftone dots as one of said colorant combinations, otherwise: deriving a plurality of mean colors, where each mean color represents an output signal value of said sensor corresponding to a known colorant combination of said color marking device; determining color differences between each pixel of said compensated image and said plurality of mean colors; and using said color differences to classify each halftone dot based on an index of a mean color that yields a minimum difference; and analyzing said classified halftone dots of at least one color separation to determine whether said color separation contains an image quality defect.