Scanner calibration correcting for foreign matter debris

An apparatus comprising:

• a media path;
• a first scanner positioned at a first location of said media path;
• a first calibration surface position at said first location of said media path across from said scanner;
• a second scanner positioned at a second location of said media path different than said first location;
• a second calibration surface position at said second location of said media path, said second scanner being movable over said second calibration surface;
• and
• a processor operatively connected to said first scanner and said second scanner,
• said first scanner including a lens causing a distortion of items scanned,
• said processor performing a calibration process of said first scanner by scanning said first calibration surface using said first scanner,
• during said calibration process, said processor performing a compensation process to remove said distortion from signals output by said first scanner when performing said scanning to identify at least one surface irregularity on said first calibration surface,
• after performing said compensation process, said processor adjusting said calibration process to apply correction for pixels affected by said surface irregularity, and
• after adjusting said calibration process, said processor finalizing said calibration process and storing first scanner settings.

A method comprising:

• performing a calibration process of a scanner positioned on a first side of a media path by scanning a calibration surface using said scanner, said calibration surface being position on a second side of said media path across from said scanner, said scanner including a lens causing a distortion of items scanned;
• during said calibration process, performing a compensation process using a processor operatively connected to said scanner to remove said distortion from signals output by said scanner when performing said scanning to identify at least one surface irregularity on said calibration surface;
• after performing said compensation process, adjusting said calibration process using said processor to apply correction for pixels affected by said surface irregularity;
• and
• after adjusting said calibration process, finalizing said calibration process and storing scanner settings, using said processor.

A method comprising:

• performing a calibration process of a scanner positioned on a first side of a media path by scanning a calibration surface using said scanner, said calibration surface being position on a second side of said media path across from said scanner, said scanner including a lens causing a distortion of items scanned;
• during said calibration process, performing a compensation process using a processor operatively connected to said scanner to remove said distortion from signals output by said scanner when performing said scanning to identify at least one surface irregularity on said calibration surface, said compensation process comprising calculating a ratio of a white reference profile to a delayed reference profile to produce a unity profile, said white reference profile comprising an undistorted profile of said calibration surface, said delay reference profile comprising said signals output by said scanner delayed by a delay period, said delay period comprising a light delay time caused by a shape of said lens, said unity profile revealing pixel-to-pixel differences up to a size of said delay period to identify said surface irregularity;
• after performing said compensation process, adjusting said calibration process using said processor to apply correction for pixels affected by said surface irregularity;
• and
• after adjusting said calibration process, finalizing said calibration process and storing scanner settings, using said processor.