An image scanner includes: a document table; a document cover; a light source; an image sensor; and a circuit configured to: acquire, as pre-reading black data, the line data that is generated by the image sensor in a state where the light source is turned off; after acquiring the pre-reading black data, acquire, as line image data, the line data that is generated by the image sensor in a state where light is emitted from the light source to an original document supported on the document table; after acquiring the line image data, acquire, as post-reading black data, the line data that is generated by the image sensor in a state where the light source is turned off; determine black reference data based on the post-reading black data and the pre-reading black data; and perform black correction on the line image data based on the black reference data.

A document reading unit includes an R light source, a G light source, a B light source, a UV light source, a lighting control unit, a first photoelectric conversion element, a second photoelectric conversion element, a lens, and an output unit. The first photoelectric conversion element includes an M filter. The second photoelectric conversion element includes a G filter. The output unit outputs outputs of the first photoelectric conversion element and the second photoelectric conversion element at the time of simultaneous lighting of the R and G light sources and an output of the first photoelectric conversion element at the time of simultaneous lighting of the B and UV light sources as the image data, and outputs an output of the second photoelectric conversion element at the time of simultaneous lighting of the B and UV light source as fluorescent color data indicating a fluorescent color region.

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 processing device includes a reception unit and a generation unit. The reception unit receives an input image signal, and a synchronization signal used to generate an output image signal on a basis of the input image signal. The generation unit generates, in a case in which the reception unit receives an initial synchronization signal of a unit of image reading, a synchronization signal for a subsequent input image signal. The reception unit receives the synchronization signal generated by the generation unit.

Provided is an image processing apparatus including as image acquiring section that acquires a plurality of images obtained by imaging, at different times, a subject irradiated with lights intensity-modulated with a plurality of modulation frequencies or modulation frequency bands; and a demodulating section that demodulates pixel values of the plurality of images with a plurality of demodulation frequencies or demodulation frequency bands based on the plurality of modulation frequencies or modulation frequency bands, for each pixel, thereby generating a plurality of pieces of pixel information indicating subject light amounts from the subject caused by each of the lights intensity-modulated with the plurality of modulation frequencies or modulation frequency bands, for each pixel.

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 method of calibrating a document scanner contact image sensor scan bar having an LED array to increase LED sensor array output and/or reduce total color scan line cycle time.

An image reading apparatus includes a light source, a detector, and an image processing unit that processes an image so as to determine a color and density of each pixel based on image signals detected by the detector. The image processing unit includes a determination unit that compares a target pixel and adjacent front and rear pixels and that determines a degree of matching of the target pixel to a condition for the target pixel to be a color shift pixel between the adjacent front and rear achromatic color pixels based on a pattern of the color and density. The image processing unit further includes a correction unit that variably sets a color shift correction amount based on the degree of matching, and that corrects the image signal by the color shift correction amount such that the target pixel which is the color shift pixel becomes an achromatic color pixel.

Signal detection and recognition employees coordinated illumination and capture of images under to facilitate extraction of a signal of interest. Pulsed illumination of different colors facilitates extraction of signals from color channels, as well as improved signal to noise ratio by combining signals of different color channels. The successive pulsing of different color illumination appears white to the user, yet facilitates signal detection, even for lower cost monochrome sensors, as in barcode scanning and other automatic identification equipment.

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.