A shading correction device includes first and second extractors, an intersection calculator, a phase shift amount calculator, a phase shifter, a generator, and a corrector. The first extractor extracts a first periodic component of original shading data. The second extractor extracts a second periodic component of a second reading result. The intersection calculator calculates a first intersection of the first component and a reference level and a second intersection of the second component and the reference level. The phase shift amount calculator calculates a phase shift amount at each of plural positions with a difference between the first and second intersections. The phase shifter shifts a phase of the first component with the phase shift amount. The generator generates corrected shading data including the phase-shifted first component and the original shading data with the first component smoothed. The corrector performs shading correction based on the corrected shading data.

A shading correction device includes first and second extractors, an intersection calculator, a phase shift amount calculator, a phase shifter, a generator, and a corrector. The first extractor extracts a first periodic component of original shading data. The second extractor extracts a second periodic component of a second reading result. The intersection calculator calculates a first intersection of the first component and a reference level and a second intersection of the second component and the reference level. The phase shift amount calculator calculates a phase shift amount at each of plural positions with a difference between the first and second intersections. The phase shifter shifts a phase of the first component with the phase shift amount. The generator generates corrected shading data including the phase-shifted first component and the original shading data with the first component smoothed. The corrector performs shading correction based on the corrected shading data.

A position of a first registration mark printed on a substrate during an earlier printing operation is detected. A second registration mark is printed on the substrate during a current printing operation at a position on the substrate relative to the first registration mark based on the detected position of the first registration mark and a correction factor. An alignment difference between the position of the first registration mark and the position of the second registration mark is measured. A new correction factor for a subsequent printing operation is calculated by weighting the measured alignment difference according to a difference between the measured alignment difference and a previous measured alignment difference.

A shading correction device includes first and second extractors, an intersection calculator, a phase shift amount calculator, a phase shifter, a generator, and a corrector. The first extractor extracts a first periodic component of original shading data. The second extractor extracts a second periodic component of a second reading result. The intersection calculator calculates a first intersection of the first component and a reference level and a second intersection of the second component and the reference level. The phase shift amount calculator calculates a phase shift amount at each of plural positions with a difference between the first and second intersections. The phase shifter shifts a phase of the first component with the phase shift amount. The generator generates corrected shading data including the phase-shifted first component and the original shading data with the first component smoothed. The corrector performs shading correction based on the corrected shading data.

A shading correction device includes first and second extractors, an intersection calculator, a phase shift amount calculator, a phase shifter, a generator, and a corrector. The first extractor extracts a first periodic component of original shading data. The second extractor extracts a second periodic component of a second reading result. The intersection calculator calculates a first intersection of the first component and a reference level and a second intersection of the second component and the reference level. The phase shift amount calculator calculates a phase shift amount at each of plural positions with a difference between the first and second intersections. The phase shifter shifts a phase of the first component with the phase shift amount. The generator generates corrected shading data including the phase-shifted first component and the original shading data with the first component smoothed. The corrector performs shading correction based on the corrected shading data.

An image processing apparatus comprises: an obtaining unit that obtains a luminance of an input image having a color reproduction range wider than that of a printing apparatus; a conversion unit that performs, for the input image, conversion processing of obtaining a value included in the color reproduction range of the printing apparatus and obtaining the luminance of the image after the conversion; and a correction unit that corrects the luminance of the input image, wherein the correction unit performs correction of the luminance of the input image based on a conversion characteristic between the obtained luminance and the obtained luminance such that an intensity of the correction becomes higher for a color that is not included in the color reproduction range of the printing apparatus than for a color included in the color reproduction range of the printing apparatus.

An image processing apparatus comprises: an obtaining unit that obtains a luminance of an input image having a color reproduction range wider than that of a printing apparatus; a conversion unit that performs, for the input image, conversion processing of obtaining a value included in the color reproduction range of the printing apparatus and obtaining the luminance of the image after the conversion; and a correction unit that corrects the luminance of the input image, wherein the correction unit performs correction of the luminance of the input image based on a conversion characteristic between the obtained luminance and the obtained luminance such that an intensity of the correction becomes higher for a color that is not included in the color reproduction range of the printing apparatus than for a color included in the color reproduction range of the printing apparatus.

An image processing apparatus includes: an input device that inputs a document image; and a controller, wherein the controller removes a streak from the image by a first method, removes a streak from the image by a second method that differs from the first method, and executes crop processing on the image from which the streaks have been removed.

An image processing apparatus includes a light source, an image sensor, and an invisible component remover. The light source emits visible component light and invisible component light to a target object. The image sensor receives reflected light from the target object to detect a visible invisible mixture image including an invisible component and a visible component and an invisible image including an invisible component. The invisible component remover, based on the visible invisible mixture image and the invisible image which have been detected, removes the invisible component from the visible invisible mixture image to generate a visible image. The invisible component remover includes a removal calculator performing a removal calculation process of an invisible component with respect to the visible invisible mixture image, and a noise reducer performing a noise reduction process on at least one of images to be input to and output from the removal calculator.

A first group of interpolation calculators performing interpolation by mean preserving interpolation calculation, and a second group of interpolation calculators performing interpolation by interpolation other than the mean preserving interpolation calculation are provided. Each of the interpolation calculators performs interpolation calculation for the missing pixel to calculate an interpolation candidate value (M(h)), and calculates test interpolation values (M(t)) treating pixels in a vicinity of the missing pixel as test pixels. A decider (4) selects one of the plurality of interpolation calculators based on results of the test interpolation. An outputter (5) selects the interpolation candidate value outputted from the interpolation calculator selected by the decider (4), among the plurality of interpolation candidate values (M(h)), and outputs the selected interpolation candidate value. Interpolation can be performed such that the interpolated pixel does not look unnatural, and yet the storage capacity and the data processing amount that are required are relatively small.