An image reading apparatus includes: N sensor chips arranged in a first direction and each including a plurality of image pickup elements arranged in the first direction; N optical systems that form, on the N sensor chips, reduced-size images of N reading ranges arranged in the first direction on a document; and an image processing section that uses image data of overlap regions to obtain positions of the overlap regions, obtains, based on the positions and predetermined synthesis reference positions in the overlap regions, magnifications of read images and synthesis positions, performs image processing of correcting the magnifications in the first direction of the image data of the N reading ranges, and combines the image data of the N reading ranges subjected to the image processing, thereby generating synthesized image data.

Techniques are described for dynamically correcting image distortion during imaging of a patterned sample having repeating spots. Different sets of image distortion correction coefficients may be calculated for different regions of a sample during a first imaging cycle of a multicycle imaging run and subsequently applied in real time to image data generated during subsequent cycles. In one implementation, image distortion correction coefficients may be calculated for an image of a patterned sample having repeated spots by: estimating an affine transform of the image; sharpening the image; and iteratively searching for an optimal set of distortion correction coefficients for the sharpened image, where iteratively searching for the optimal set of distortion correction coefficients for the sharpened image includes calculating a mean chastity for spot locations in the image, and where the estimated affine transform is applied during each iteration of the search.

Techniques are described for dynamically correcting image distortion during imaging of a patterned sample having repeating spots. Different sets of image distortion correction coefficients may be calculated for different regions of a sample during a first imaging cycle of a multicycle imaging run and subsequently applied in real time to image data generated during subsequent cycles. In one implementation, image distortion correction coefficients may be calculated for an image of a patterned sample having repeated spots by: estimating an affine transform of the image; sharpening the image; and iteratively searching for an optimal set of distortion correction coefficients for the sharpened image, where iteratively searching for the optimal set of distortion correction coefficients for the sharpened image includes calculating a mean chastity for spot locations in the image, and where the estimated affine transform is applied during each iteration of the search.

An image reading device that efficiently performs shading correction that flexibly responds to changes in the diffusion properties of reflected light on the surface of a reading target efficiently performing same as a result of including: controlling a plurality of light sources so as to cause only a specific light source among the light sources to be lit; obtaining the diffusion state of a first reflected light generated by the specific light source being lit, in a state in which general shading correction data not dependent on the image reading target is generated; obtaining a diffusion state for a second reflected light generated by light being irradiated on to the reading target by the specific light source; and generating dedicated shading correction data that relies on the reading target, based on the first reflected light diffusion state, the second reflected light diffusion state, and the general shading correction data.

An image reading device that efficiently performs shading correction that flexibly responds to changes in the diffusion properties of reflected light on the surface of a reading target efficiently performing same as a result of including: controlling a plurality of light sources so as to cause only a specific light source among the light sources to be lit; obtaining the diffusion state of a first reflected light generated by the specific light source being lit, in a state in which general shading correction data not dependent on the image reading target is generated; obtaining a diffusion state for a second reflected light generated by light being irradiated on to the reading target by the specific light source; and generating dedicated shading correction data that relies on the reading target, based on the first reflected light diffusion state, the second reflected light diffusion state, and the general shading correction data.

An image reading device includes a background unit, a reading unit, and circuitry. The background unit is configured to be a background in reading of a recording medium and includes a first region that is black and a second region that is different from the first region. The reading unit is configured to read an image with the background unit as the background, and generate a read value based on a result of reading the image with the background unit. The circuitry is configured to correct the read value based on a reference value generated by the reading unit by reading the second region of the background unit.

An image reading device includes a background unit, a reading unit, and circuitry. The background unit is configured to be a background in reading of a recording medium and includes a first region that is black and a second region that is different from the first region. The reading unit is configured to read an image with the background unit as the background, and generate a read value based on a result of reading the image with the background unit. The circuitry is configured to correct the read value based on a reference value generated by the reading unit by reading the second region of the background unit.

A method for brightness and color correction of image data of a line camera is disclosed, wherein, for the detecting of image data with at least two line arrays of the line camera while illuminating a detection area of the line camera with an illumination module, a gray-scale image and at least two single-color images are recorded, and the image data is corrected with the help of a brightness function of the illumination module which is dependent on a line position of the line array and/or a distance of recorded objects. The brightness function is determined for the illumination module in advance and independent of the line camera and is stored in the illumination module, and the brightness function is read out by the line camera and used for the respective correction of the gray-scale image and the single-color images.

An object of the present disclosure is to implement highly accurate image connecting processing between line sensors. One embodiment of the present invention is an image reading apparatus having: a plurality of line image sensors arrayed in a first direction; a conveyance unit configured to convey a document in a second direction intersecting with the first direction; a calculation unit configured to calculate a correction value for correcting a deviation at the time of connecting image data obtained by each of the plurality of line image sensors based on read data obtained by reading a chart with the plurality of line image sensors, on which a plurality of dot patterns is printed and which is conveyed by the conveyance unit; a measurement unit configured to measure an amount of conveyance in the first direction in a case where the document is conveyed in the second direction by the conveyance unit.

An object of the present disclosure is to implement highly accurate image connecting processing between line sensors. One embodiment of the present invention is an image reading apparatus having: a plurality of line image sensors arrayed in a first direction; a conveyance unit configured to convey a document in a second direction intersecting with the first direction; a calculation unit configured to calculate a correction value for correcting a deviation at the time of connecting image data obtained by each of the plurality of line image sensors based on read data obtained by reading a chart with the plurality of line image sensors, on which a plurality of dot patterns is printed and which is conveyed by the conveyance unit; a measurement unit configured to measure an amount of conveyance in the first direction in a case where the document is conveyed in the second direction by the conveyance unit.