Patent ID: 8493444

Claim:
A system for detecting blockage of an aperture associated with an image sensor as a plurality of items are sequentially advanced proximal to the aperture, the system comprising: an image sensor configured to obtain an image of a first item having been advanced to a position proximal an aperture through which the image sensor images at least portion of the item; a memory configured to store data associated with at least one previously obtained image of a second item advanced proximal to the aperture; and at least one processor configured to: detect a horizontal void extending across the image of the first item; identify parameters relating to the size and position of the horizontal void in the image of the first item; compare the parameters relating to the size and position of the horizontal void identified in the image of the first item with stored parameters relating to the size and position of a horizontal void in at least one previously obtained image of the second item to determine if the size and position of the horizontal voids substantially match; and if the size and position of the horizontal voids substantially match, provide an indicator of a blockage of the aperture of the image sensor [based on the comparison].