A method is provided for constructing a composite image. The method comprises illuminating an object with light of a particular spectral band, capturing a digital image of the illuminated object using a monochromatic image sensor of an imaging device to obtain a monochrome image, repeating the steps of illuminating and capturing to obtain a plurality of monochrome images of the object illuminated by light of a plurality of different spectral bands, processing the plurality of monochrome images to generate image data for one or more output channels, and generating a color composite image from the image data. The color composite image comprises the one or more output channels.

A system and method are described for enhancing readability of document images by operating on each document individually. Monochromatic light sources operating at different wavelengths of light can be used to obtain greyscale images. The greyscale images can then be used in any desired image enhancement algorithm. In one example algorithm, an automated method removes image background noise and improves sharpness of the scripts and characters using edge detection and local color contrast computation.

An image processing apparatus is provided to alleviate degradation of the gradation of a color image in the case where images having a sensitivity different from each other are obtained by imaging one same object in black-and-white and color. The image processing apparatus includes a gradation control part obtaining a brightness signal representing a black-and-white image and a chroma signal representing a color image obtained by imaging a same object as that for the black-and-white image and that controls gradation of the chroma signal on the basis of the brightness signal. This configuration can suppress degradation of the gradation of a color image to be minimal in the case where images having a sensitivity different from each other are obtained by imaging one same object in black-and-white and color.

A system and method are described for enhancing readability of document images by operating on each document individually. Monochromatic light sources operating at different wavelengths of light can be used to obtain greyscale images. The greyscale images can then be used in any desired image enhancement algorithm. In one example algorithm, an automated method removes image background noise and improves sharpness of the scripts and characters using edge detection and local color contrast computation.

An image reading apparatus includes a reading module. The reading module includes a linear light source that extends in a direction intersecting a moving direction in which the transport unit relatively moves and irradiates a document with light via a transparent member, an image forming element that condenses the light reflected from the document, and a light receiving element that receives the light condensed by the image forming element. The linear light source is disposed such that a main optical axis of the linear light source is inclined at a first angle with respect to a normal direction of the transparent member in the moving direction, and the image forming element is inclined at a second angle in the same direction as the inclination of the main optical axis of the linear light source.

An image reading apparatus includes a reading module. The reading module includes a linear light source that extends in a direction intersecting a moving direction in which the transport unit relatively moves and irradiates a document with light via a transparent member, an image forming element that condenses the light reflected from the document, and a light receiving element that receives the light condensed by the image forming element. The linear light source is disposed such that a main optical axis of the linear light source is inclined at a first angle with respect to a normal direction of the transparent member in the moving direction, and the image forming element is inclined at a second angle in the same direction as the inclination of the main optical axis of the linear light source.

First, second, and third line reading processing is processing of emitting light of each color to first, second, and third line of an original document in first, second, and third lighting order, respectively, and reading reflection light of the emitted light. A color that is first in the first lighting order, a color that is first in the second lighting order, and a color that is first in the third lighting order are different from each other. A color that is second in the first lighting order, a color that is second in the second lighting order, and a color that is second in the third lighting order is different from each other. A color that is third in the first lighting order, a color that is third in the second lighting order, and a color that is third in the third lighting order is different from each other.

An image forming apparatus includes an optical sensor configured to detect reflected light from a detection image formed on the transfer member. The optical sensor includes a light emitting element configured to emit light for irradiating the detection image at a predetermined angle of incidence, a first light receiving element arranged at a position at which diffused reflected light from the detection image is received at a first angle of reflection, and a second light receiving element arranged at a position at which the diffused reflected light from the detection image is received at a second angle of reflection.

A method is provided for constructing a composite image. The method comprises illuminating an object with light of a particular spectral band, capturing a digital image of the illuminated object using a monochromatic image sensor of an imaging device to obtain a monochrome image, repeating the steps of illuminating and capturing to obtain a plurality of monochrome images of the object illuminated by light of a plurality of different spectral bands, processing the plurality of monochrome images to generate image data for one or more output channels, and generating a color composite image from the image data. The color composite image comprises the one or more output channels.

A sensor array assembly including a first sensor array, a second sensor array and a mounting substrate. The first sensor array includes a first process direction width and a first photosite, while the second sensor array includes a second process direction width and a second photosite. The first and second sensor arrays are separately secured on the mounting substrate. The first photosite is in precision alignment with the second photosite.