# US 2014/0153058 A1 · Scanner calibration correcting for foreign matter debris > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153058 A1 - Document ID: US20140153058A1 - Status: Published application - Kind: A1 - Application number: 13/689,835 - Filed: 2012-11-30 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Xerox Corporation - Applicants: Xerox Corporation - Inventors: Whynn V. Lovette - Web page: https://patentgrep.com/patent/US20140153058A1 ## CPC - H04N 1/00013: {Reading apparatus} - H04N 1/00031: {Testing, i.e. determining the result of a trial (H04N1/00029 takes precedence; using test signals for transmission mode changing H04N2201/33371)} - H04N 1/00045: {using a reference pattern designed for the purpose, e.g. a test chart} - H04N 1/00063: {using at least a part of the apparatus itself, e.g. self-testing} - H04N 1/00087: {Setting or calibrating (picture signal circuits H04N1/40)} - H04N 1/1215: {Feeding using one or more cylindrical platens or rollers in the immediate vicinity of the main scanning line} - H04N 1/1235: {Feeding a sheet past a transparent plate; Details thereof} - H04N 1/125: {the sheet feeding apparatus serving an auxiliary function, e.g. as a white reference} - H04N 1/193: using electrically scanned linear arrays {, e.g. linear CCD arrays} - H04N 2201/0081: Image reader (H04N2201/0091 - H04N2201/0094 take precedence) - H04N 2201/044: Moving a scanning element into cooperation with a calibration element, e.g. a grey-wedge mounted on the document support, or vice versa - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Devices and methods calibrate an optical scanner by having the scanner scan a calibration surface. The scanner includes a lens causing a distortion of items scanned. During the calibration process, such devices and methods perform a compensation process to remove the distortion from signals output by the scanner when performing the scanning to identify at least one surface irregularity on the calibration surface. After performing the compensation process, the devices and methods adjust the calibration process (using the processor) to apply correction for pixels affected by the surface irregularity. Then, after adjusting the calibration settings, such devices and methods finalize the calibration process and store the scanner settings, again using the processor. ## Claims ### Claim 1 An apparatus comprising: a media path; a scanner positioned on a first side of said media path; a calibration surface position on a second side of said media path across from said scanner, said first side of said media path being opposite said second side of said media path; and a processor operatively connected to said scanner, said scanner including a lens causing a distortion of items scanned, said processor performing a calibration process of said scanner using dedicated calibration hardware, by scanning said calibration surface using said scanner, during said calibration process, said processor and dedicated hardware performing a compensation process 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, said processor adjusting said calibration hardware to apply correction for pixels affected by said surface irregularity, and after adjusting said calibration hardware, said processor and hardware finalizing said calibration process and storing scanner settings. ### Claim 2 (depends on 1) The apparatus according to claim 1, said compensation process increasing prominence of signals identifying said surface irregularity by removing said distortion from said signals output by said scanner. ### Claim 3 (depends on 1) The apparatus according to claim 1, after storing said scanner settings, said scanner scanning sheets of media moving along said media path as said sheets of media pass by said scanner using said scanner settings, said correction only being applied during said calibration process and said correction not being applied during said scanning of said sheets of media. ### Claim 4 (depends on 1) The apparatus according to claim 1, said scanner and said calibration surface being in fixed, non-movable locations with respect to each other and with respect to said media path. ### Claim 5 (depends on 1) The apparatus according to claim 1, said correction comprising using settings of adjacent pixels as settings for said pixels affected by said surface irregularity, said adjacent pixels being directly next to said pixels affected by said surface irregularity, and said adjacent pixels not being affected by said surface irregularity. ### Claim 6 (depends on 1) The apparatus according to claim 1, said processor identifying said surface irregularity by matching said signals output by said scanner to known signals caused by surface debris. ### Claim 7 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. ### Claim 8 (depends on 7) The apparatus according to claim 7, said compensation process increasing prominence of signals identifying said surface irregularity by removing said distortion from said signals output by said first scanner. ### Claim 9 (depends on 7) The apparatus according to claim 7, after storing said first scanner settings, said scanner scanning sheets of media moving along said media path as said sheets of media pass by said first scanner using said first scanner settings, said correction only being applied during said calibration process and said correction not being applied during said scanning of said sheets of media. ### Claim 10 (depends on 7) The apparatus according to claim 7, said first scanner and said first calibration surface being in fixed, non-movable locations with respect to each other and with respect to said media path. ### Claim 11 (depends on 7) The apparatus according to claim 7, said correction comprising using settings of adjacent pixels as settings for said pixels affected by said surface irregularity, said adjacent pixels being directly next to said pixels affected by said surface irregularity, and said adjacent pixels not being affected by said surface irregularity. ### Claim 12 (depends on 7) The apparatus according to claim 7, said processor identifying said surface irregularity by matching said signals output by said first scanner to known signals caused by surface debris. ### Claim 13 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. ### Claim 14 (depends on 13) The method according to claim 13, said compensation process increasing prominence of signals identifying said surface irregularity by removing said distortion from said signals output by said scanner. ### Claim 15 (depends on 13) The method according to claim 13, further comprising after storing said scanner settings, scanning sheets of media moving along said media path as said sheets of media pass by said scanner using said scanner settings, said correction only being applied during said calibration process and said correction not being applied during said scanning of said sheets of media. ### Claim 16 (depends on 13) The method according to claim 13, said scanner and said calibration surface being in fixed, non-movable locations with respect to each other and with respect to said media path. ### Claim 17 (depends on 13) The method according to claim 13, said correction comprising using settings of adjacent pixels as settings for said pixels affected by said surface irregularity, said adjacent pixels being directly next to said pixels affected by said surface irregularity, and said adjacent pixels not being affected by said surface irregularity. ### Claim 18 (depends on 13) The method according to claim 13, further comprising identifying said surface irregularity by matching said signals output by said scanner to known signals caused by surface debris. ### Claim 19 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. ### Claim 20 (depends on 19) The method according to claim 19, said compensation process increasing prominence of signals identifying said surface irregularity by removing said distortion from said signals output by said scanner. ### Claim 21 (depends on 19) The method according to claim 19, further comprising after storing said scanner settings, scanning sheets of media moving along said media path as said sheets of media pass by said scanner using said scanner settings, said correction only being applied during said calibration process and said correction not being applied during said scanning of said sheets of media. ### Claim 22 (depends on 19) The method according to claim 19, said scanner and said calibration surface being in fixed, non-movable locations with respect to each other and with respect to said media path. ### Claim 23 (depends on 19) The method according to claim 19, said correction comprising using settings of adjacent pixels as settings for said pixels affected by said surface irregularity, said adjacent pixels being directly next to said pixels affected by said surface irregularity, and said adjacent pixels not being affected by said surface irregularity. ### Claim 24 (depends on 19) The method according to claim 19, further comprising identifying said surface irregularity by matching said signals output by said scanner to known signals caused by surface debris.