Patent ID: 8922641

Claim:
A method of inspecting a component of a hygienic article comprising: storing, within a memory, a reference image of a first component used to produce a hygienic article, wherein the first component is free of defects and comprises a feature and wherein the reference image is captured when the first component passes a camera; illuminating, at the camera, a second component with an illumination color that increases the contrast of a feature of the second component within an image, wherein the feature of the second component comprises a first color and a second color, wherein the first color has a corresponding first illumination color for increasing the contrast of the first color in an image and the second color has a corresponding second illumination color for increasing the contrast of the second color in an image, wherein the illumination color is an average of the first illumination color and the second illumination color; triggering, by a trigger device, the capture of a single inspection image of the second component by the camera; generating, by a processor, a residual image by performing image subtraction between the reference image and the inspection image; detecting, by the processor, a variation between the first component and the second component using the residual image; generating a rejection command that causes the second component to be rejected, in response to the variation being detected; defining one or more boundaries in the reference image to indicate a subset of the reference image for comparison to the inspection image; using the boundaries to select a subset of the inspection image that corresponds to the subset of the reference image; determining, by the processor, if a plurality of rejection commands have been generated; and issuing a switching command to a printer that causes the printer to switch between print heads of the printer, wherein the printer printed the graphic or text and wherein the feature of the first component and the feature of the second component comprise a printed graphic or printed text; and wherein the image subtraction is performed between the subset of the reference image and the subset of the inspection image.