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Methods and apparatus for inspecting the appearance of substantially circular objects

  • US 5,353,357 A
  • Filed: 12/04/1992
  • Issued: 10/04/1994
  • Est. Priority Date: 12/04/1992
  • Status: Expired due to Term
First Claim
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1. Apparatus for determining whether an end surface of a cigarette has an acceptable appearance, said apparatus comprising:

  • means for forming an image of said end surface against a contrasting background;

    means for digitizing said image as a plurality of pixels, each of said pixels having an initial digital value indicative of the brightness of a corresponding portion of said image;

    means for processing said pixels so that each pixel having an initial digital value which has a first polarity relative to a predetermined threshold value is assigned a first of two processed digital values, and so that all other pixels are assigned a second of said two processed digital values, said threshold values being selected so that said background and substantially discolored area of said end surface are assigned said first processed digital value and substantially undiscolored areas of said end surface are assigned said second processed digital value;

    means for identifying as edge pixels those pixels which are adjacent to transitions between pixels having said first and second processed digital values;

    means for associating edge pixels which are adjacent to one another so as to identify a boundary of each blob in said image;

    means for identifying each blob as a first type of blob or a second type of blob by determining whether each boundary surrounds pixels having said first processed digital value or said second processed digital value, respectively;

    means for calculating a characteristic of any blob of at least one of said blob types; and

    means for determining acceptability of said image by comparing said calculated characteristic to a predetermined value.

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