An image reading device includes a first scanner, a second scanner, and circuitry. The first scanner is configured to read a first side of a recording medium. The second scanner is configured to read a second side of the recording medium. The circuitry is configured to generate a first correction value to correct misalignment between the first side and the second side. The circuitry is configured to input a second correction value. The circuitry is configured to correct an image based on the first correction value and the second correction value.

A signal correction device includes a correction signal generator configured to generate a correction signal serving to remove noise superimposed on an input signal; a phase adjuster configured to shift a phase of the correction signal generated by the correction signal generator; a subtractor configured to generate an output signal for output by subtracting the correction signal from the input signal; a peak and bottom detector configured to detect a peak value and a bottom value of the output signal; and a determiner configured to determine a phase-shift amount of the phase adjuster from the peak value and the bottom value of the output signal detected by the peak and bottom detector. The determiner detects uncorrected noise from the peak value and the bottom value of the output signal from the subtractor, and sets the phase-shift amount such that the uncorrected noise is reduced to a minimum.

A digital printing system having a linear printhead includes corrections for in-track position errors. A data processing system implements a method for determining an in-track position function which includes printing a test target including a plurality of alignment marks, automatically analyzing a captured image of the printed test target to determine a measured in-track position for each of the alignment marks, comparing the measured in-track positions for the alignment marks to reference in-track positions to determine measured in-track position errors, and determining an in-track position correction function responsive to the measured in-track position errors. The in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

An image reading device includes a first scanner, a second scanner, and circuitry. The first scanner is configured to read a first side of a recording medium. The second scanner is configured to read a second side of the recording medium. The circuitry is configured to generate a first correction value to correct misalignment between the first side and the second side. The circuitry is configured to input a second correction value. The circuitry is configured to correct an image based on the first correction value and the second correction value.

A digital printing system having a linear printhead includes corrections for cross-track position errors. A data processing system implements a method for determining a cross-track position function which includes printing a test target including a plurality of alignment marks, automatically analyzing a captured image of the printed test target to determine a measured position for each of the alignment marks, comparing the measured positions for the alignment marks to reference positions to determine measured cross-track position errors, and determining a cross-track position correction function responsive to the measured position errors. The cross-track position correction function specifies cross-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling the image lines of a digital image responsive to the cross-track position correction function.

A method for correcting in-track position errors in a digital printing system having a linear printhead includes printing a test target including a plurality of alignment marks. A data processing system is used to automatically analyze a captured image of the printed test target to determine a measured in-track position for each of the alignment marks. The measured in-track positions for the alignment marks are compared to reference positions to determine measured in-track position errors. An in-track position correction function is determined responsive to the measured in-track position errors, wherein the in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

A signal correction device includes a correction signal generator configured to generate a correction signal serving to remove noise superimposed on an input signal; a phase adjuster configured to shift a phase of the correction signal generated by the correction signal generator; a subtractor configured to generate an output signal for output by subtracting the correction signal from the input signal; a peak and bottom detector configured to detect a peak value and a bottom value of the output signal; and a determiner configured to determine a phase-shift amount of the phase adjuster from the peak value and the bottom value of the output signal detected by the peak and bottom detector. The determiner detects uncorrected noise from the peak value and the bottom value of the output signal from the subtractor, and sets the phase-shift amount such that the uncorrected noise is reduced to a minimum.

A method for correcting in-track position errors in a digital printing system having a linear printhead includes printing a test target including a plurality of alignment marks. A data processing system is used to automatically analyze a captured image of the printed test target to determine a measured in-track position for each of the alignment marks. The measured in-track positions for the alignment marks are compared to reference positions to determine measured in-track position errors. An in-track position correction function is determined responsive to the measured in-track position errors, wherein the in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

A digital printing system having a linear printhead includes corrections for in-track position errors. A data processing system implements a method for determining an in-track position function which includes printing a test target including a plurality of alignment marks, automatically analyzing a captured image of the printed test target to determine a measured in-track position for each of the alignment marks, comparing the measured in-track positions for the alignment marks to reference in-track positions to determine measured in-track position errors, and determining an in-track position correction function responsive to the measured in-track position errors. The in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

A method for correcting cross-track position errors in a digital printing system having a linear printhead includes printing a test target including a plurality of alignment marks. A data processing system is used to automatically analyze a captured image of the printed test target to determine a measured position for each of the alignment marks. The measured positions for the alignment marks is compared to reference positions to determine measured cross-track position errors. A cross-track position correction function is determined responsive to the measured position errors, wherein the cross-track position correction function specifies cross-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling the image lines of a digital image responsive to the cross-track position correction function.