An image reading device includes: a scanner glass; photo-sensors arranged at intervals in a main scanning direction to read a document conveyed in a sub-scanning direction; an adjuster that adjusts the size of an overlapping area between a first and second image obtained by neighboring photo-sensors, the overlapping area constituting a first area of the first image and a second area of the second image; a superimposing portion that shifts either one of images of the first and second area to the other one; a judgment portion that judges whether the images having different focal depths exist based on the degree of matching between the first and second area; and a detector that detects a foreign body on the scanner glass platen by detecting a continuous image stretching in a document conveying direction in both of the images having different focal depths, if the images having different focal depths exist.

There is provided a scanner that combines images read by a first sensor array and a second sensor array, in which the first sensor array and the second sensor array have read regions which are overlapped partially, and includes a combining section that combines a first read image read by the first sensor array and a second read image read by the second sensor array and a correction section that corrects an image after a combining based on a degree of displacement of a reading position of the document.

There is provided a scanner that combines images read by a first sensor array and a second sensor array, in which the first sensor array and the second sensor array have read regions which are overlapped partially, and includes a combining section that combines a straight line as an image of a non-straight line in a case where the straight line which is non-parallel and non-perpendicular in a main scanning direction is read in an overlapped manner by the first sensor array and the second sensor array.

Image processors are provided for respective groups formed by grouping of images, the order of which is sequential when images respectively having overlapping portions corresponding to the same portion of an object are arranged so as to be adjacent to each other, and concurrently perform processing to detect combining-position information for combining an image in a group and an image adjacent to the image without any positional displacement by image-matching. The combining-position information between images belonging to different groups is respectively transferred, via combination-information transferring paths, between the image processors and between the image processors.

A method, and document scanner system, for correcting image values recorded by an optical document scanner with multiple color cameras arranged in a staggered configuration with overlap scan areas includes storing color correction values mapped to respective color index values, where a color correction value is computed from a color difference between a first color value and a second color value of the respective overlap sets, and correcting a third color value which is a color value from the second set of color image values by a color correction value which is looked up via a color index value determined from the third color value. Thereby color variations among staggered cameras are corrected.

A read image processing apparatus is provided for processing a read image read by line image sensors arranged such that one end parts of which adjacent to each other are overlapped in a sub-scanning direction. The read image processing apparatus includes a density variation detector, a seam processor, and a line image generator. The density variation detector detects whether a density variation occurs for not less than a predetermined number of times or not in each of a plurality of regions in a seam-read image. The seam processor generates a seam image by synthesizing the seam-read images read by the line image sensors adjacent to each other in accordance with a detection result made by the density variation detector. The line image generator generates a read image corresponding to one line based on read images read by the line image sensors and the seam image generated by the seam processor.

Disclosed is a method and a scanning device for digital image scanning of a surface of an object. The scanning device comprising a light source for illuminating the object. The scanning device comprising a first image sensor configured for capturing a first set of images of a first region of the object, where the first region is illuminated by the light source. The scanning device comprising a second image sensor configured for capturing a second set of images of a second region of the object, where the second region is illuminated by the light source. The scanning device comprising a laser component configured for projecting laser light onto the object. The projected laser light has a shape of a cross on the object. The first image sensor and the second image sensor are configured to capture/cover an overlapping region on the object. The overlapping region comprising a part of the first region of the object and a part of the second region of the object. The laser light from the laser component is configured to be projected onto the overlapping region. The first image sensor and the second image sensor are configured for capturing a third set of images and a fourth set of images, respectively, of the object including the projected laser light on the overlapping region.