An image processing apparatus comprising: a storage unit configured to store image data read by scanning, with a linear sensor including pixels arranged in a main-scanning direction, an original in a sub-scanning direction orthogonal to the main-scanning direction, an acquisition unit configured to acquire inclination information indicating inclination of the image data, and a readout unit configured to read out the image data from the storage unit, with shifting, in accordance with the inclination information, a line position in the sub-scanning direction by each predetermined number of pixels in the main-scanning direction, wherein the readout unit reads out the image data from the storage unit, based on the inclination information, differentiating the predetermined number of pixels between an edge in the main-scanning direction and other parts.

An image processing apparatus comprising: a storage unit configured to store image data read by scanning, with a linear sensor including pixels arranged in a main-scanning direction, an original in a sub-scanning direction orthogonal to the main-scanning direction, an acquisition unit configured to acquire inclination information indicating inclination of the image data, and a readout unit configured to read out the image data from the storage unit, with shifting, in accordance with the inclination information, a line position in the sub-scanning direction by each predetermined number of pixels in the main-scanning direction, wherein the readout unit reads out the image data from the storage unit, based on the inclination information, differentiating the predetermined number of pixels between an edge in the main-scanning direction and other parts.

An optical member includes a lens array including lens bodies, and transmissive members. The transmissive members are made of a material having a uniform refractive index, and are disposed at positions nearer an object-to-be-read than the corresponding lens bodies are disposed or at positions farther from the object-to-be-read than the corresponding lens bodies are disposed. The transmissive members have a columnar shape extending along the optical axes of the lens bodies, and allow light incident through one end faces to exit through the other end faces. At least either ones of the lens bodies or the transmissive members are arranged with distances therebetween larger than errors in the arrangement of the lens bodies and the transmissive members.

An optical member includes a lens array including lens bodies, and transmissive members. The transmissive members are made of a material having a uniform refractive index, and are disposed at positions nearer an object-to-be-read than the corresponding lens bodies are disposed or at positions farther from the object-to-be-read than the corresponding lens bodies are disposed. The transmissive members have a columnar shape extending along the optical axes of the lens bodies, and allow light incident through one end faces to exit through the other end faces. At least either ones of the lens bodies or the transmissive members are arranged with distances therebetween larger than errors in the arrangement of the lens bodies and the transmissive members.

A scanner includes: a first mirror having a plurality of concavities configured to reflect light from a document; a sensor group having a sensor chip with a photoelectric conversion element line configured to detect light reflected by the concavity; and an aperture member having a plurality of apertures corresponding one-to-one to the concavities and disposed between the first mirror and the sensor group on an optical path of light reflected by the concavity; the equivalent f-number of the aperture being 6 or greater.

In a line sensor including color filters that are periodically disposed in a light-receiving-element row, a problem called a mixture of colors occurs. A mixture of colors occurs when light that has been transmitted through a color filter differing from a color filter corresponding to a light receiving element is incident upon the light receiving element.

In a CMOS sensor 107 including a light-receiving-element row in which a plurality of photodiodes 1204 are disposed side by side in a main scanning direction and a plurality of color filters 1202 that are disposed in correspondence with the plurality of photodiodes 1204, the center of each color filter 1202 is displaced in a direction of the center of the light-receiving-element row from the center of the photodiode 1204 corresponding to the color filter.

In a line sensor including color filters that are periodically disposed in a light-receiving-element row, a problem called a mixture of colors occurs. A mixture of colors occurs when light that has been transmitted through a color filter differing from a color filter corresponding to a light receiving element is incident upon the light receiving element.

In a CMOS sensor 107 including a light-receiving-element row in which a plurality of photodiodes 1204 are disposed side by side in a main scanning direction and a plurality of color filters 1202 that are disposed in correspondence with the plurality of photodiodes 1204, the center of each color filter 1202 is displaced in a direction of the center of the light-receiving-element row from the center of the photodiode 1204 corresponding to the color filter.

Provided is a signal processing apparatus that enables an image reading apparatus to perform higher speed processing of reading a document image. A signal processing unit is configured to convert six analog image signals obtained from a line sensor into six first signals, each of which is a 10-bit digital image signal, respectively, and to write the six first signals into a RAM at a first speed that is the same as a frequency of the analog image signals. The signal processing unit is configured to cause a serialization unit to read out from the RAM the six first signals as four second signals, each of which is a 10-bit digital image signal, at a second speed higher than the first speed, respectively, and to serialize the four second signals to generate six 7-bit serial signals.

Provided is a signal processing apparatus that enables an image reading apparatus to perform higher speed processing of reading a document image. A signal processing unit is configured to convert six analog image signals obtained from a line sensor into six first signals, each of which is a 10-bit digital image signal, respectively, and to write the six first signals into a RAM at a first speed that is the same as a frequency of the analog image signals. The signal processing unit is configured to cause a serialization unit to read out from the RAM the six first signals as four second signals, each of which is a 10-bit digital image signal, at a second speed higher than the first speed, respectively, and to serialize the four second signals to generate six 7-bit serial signals.

In one example, a document scanner has a fixed-position scan bar and a built-in translatable calibration target. The scan bar has a linear array of imaging elements aimed in an imaging direction. The calibration target is spaced apart from and parallel to the linear array, and has a planar surface orthogonal to the imaging direction spanning the length of the linear array. The target is translatable during a calibration in a direction in a plane of the surface.