The present invention relates to an apparatus for imaging a page of a book or other similar document comprising: a table defining a support plane, the book being disposed on the table such that the page to image is substantially parallel to the support plane and an other page of the book is orientated at an angle relative to the support plane, being between 0 and 70; means for displacing the table parallel to the support plane along a longitudinal direction and a lateral direction and/or perpendicular to the support plane along a normal direction; a plurality of light sources, each light source producing an incident light and directing said incident light onto an inspection area of the page to image at a predetermined zenith angle .sub.i and at a predetermined azimuth angle .sub.i; means for sensing the light reflected by the page to image; at least one control unit adapted to control said displacing means, said light sources and said sensing means; wherein the light sources are fixedly connected to a main frame, said main frame defining a partially or fully hemispherical dome; wherein said main frame comprises a first module and a second module, said second module being detachably connected to the first module at a first end thereof, said first end defining a plane that is obliquely orientated at an angle relative to the support plane; and wherein, when the second module is disconnected from the first module, a free space between the first end of the first module and the support plane is adapted to permit the movement of the table and the book in the longitudinal and lateral directions without coming into contact with the main frame.

An image reading apparatus includes a gray reference member, a reading unit, an adjusting unit, a calibration unit, a storage unit, and a control unit. The control unit is configured to execute a first preprocessing and a second preprocessing. The first preprocessing includes: acquiring first black data from one line worth of image data; acquiring white data; calculating white-black difference data; acquiring first light gray data; and calculating first light gray-black difference data. The second processing includes: acquiring second black data from the one line worth of the image data; acquiring second light gray data; calculating second light gray-black difference data; calculating a change ratio by dividing the second light gray-black difference data by the first light gray-black difference data; and calculating calibration data by multiplying the white-black difference data by the change ratio. Shading of the image data is calibrated in response to the calibration data.

The present invention relates to an apparatus for imaging a page of a book or other similar document comprising: a table defining a support plane, the book being disposed on the table such that the page to image is substantially parallel to the support plane and an other page of the book is orientated at an angle relative to the support plane, a being between 0 and 70; means for displacing the table parallel to the support plane along a longitudinal direction and a lateral direction and/or perpendicular to the support plane along a normal direction; a plurality of light sources, each light source producing an incident light and directing said incident light onto an inspection area of the page to image at a predetermined zenith angle .sub.i and at a predetermined azimuth angle .sub.i; means for sensing the light reflected by the page to image; at least one control unit adapted to control said displacing means, said light sources and said sensing means;

wherein the light sources are fixedly connected to a main frame, said main frame defining a partially or fully hemispherical dome;

wherein said main frame comprises a first module and a second module, said second module being detachably connected to the first module at a first end thereof, said first end defining a plane that is obliquely orientated at an angle relative to the support plane; and

wherein, when the second module is disconnected from the first module, a free space between the first end of the first module and the support plane is adapted to permit the movement of the table and the book in the longitudinal and lateral directions without coming into contact with the main frame.

A linear light source assembly including a light guide bar with patterned light emitting surface, a reflective holder, a light emitting diode (LED) light source module, and a flexible printed circuit (FPC) is disclosed. The light guide bar is an elongated polygonal transparent material with a light-scattering patterned light emitting surface where the light exits. The FPC is a flexible plastic substrate with a plurality of conductive traces and a plurality of FPC holes in the flexible plastic substrate. The light guide bar is disposed in the holder. The LED light source module is attached to the FPC. Holder posts are inserted into the FPC holes to align and hold the FPC with LED light source module to the holder and position the LED light source module adjacent to a light-receiving end of the light guide bar.

An image reading device includes plural light sources that irradiate an image reading target with light at different angles; and a switching mechanism that sequentially switches the light incident to the image reading target from the plural light sources during an image reading operation on the image reading target.

A rod lens array 10a includes a plurality of gradient-index rod lenses 1b arrayed to have optical axes parallel to each other, and forms an erecting equal-magnification image. The gradient-index rod lenses 1b each have a refractive-index distribution in a radial direction thereof. The refractive-index distribution n(r) is approximated by n(r)=n.sub.0.Math.{1(A/2).Math.r.sup.2}, where a refractive index at a center of the gradient-index rod lens 1b is represented by n.sub.0, a refractive-index distribution constant of the gradient-index rod lens 1b is represented by A, and a distance from the center of the gradient-index rod lens 1b is represented by r. The gradient-index rod lens 1b has an aperture angle of 3 to 6, the aperture angle represented by =sin.sup.1(n.sub.0A.Math.r.sub.0), where a radius of the gradient-index rod lens is represented by r.sub.0. The rod lens array 10a has an imaging distance of 45 to 75 mm and a depth of field of 1.5 to 3.0 mm with value of modulation transfer function (MTF) of 30% or more at a spatial frequency of 6 lp/mm.

An imaging device includes: M rotatable photosensitive drums, at least one display chip, at least one projection lens, and at least one beam deflection system. The light-receiving region of each photosensitive drum includes multiple light-receiving sub-regions. Each display chip includes at least two light-emitting regions arranged in a first direction. At least one projection lens is in one-to-one correspondence with the at least one display chip. Each projection lens is configured to form an image for a corresponding display chip. The at least one beam deflection system is in one-to-one correspondence with the at least one display chip. The beam deflection system is configured to deflect an image, which is formed by light from each light-emitting region in the display chip through a corresponding projection lens, to a corresponding light-receiving sub-region.

A rod lens array 10a includes a plurality of gradient-index rod lenses 1b arrayed to have optical axes parallel to each other, and forms an erecting equal-magnification image. The gradient-index rod lenses 1b each have a refractive-index distribution in a radial direction thereof. The refractive-index distribution n(r) is approximated by n(r)=n.sub.0.Math.{1(A/2).Math.r.sup.2}, where a refractive index at a center of the gradient-index rod lens 1b is represented by n.sub.0, a refractive-index distribution constant of the gradient-index rod lens 1b is represented by A, and a distance from the center of the gradient-index rod lens 1b is represented by r. The gradient-index rod lens 1b has an aperture angle of 3 to 6, the aperture angle represented by =sin.sup.1(n.sub.0.Math.A.Math.r.sub.0), where a radius of the gradient-index rod lens is represented by r.sub.0. The rod lens array 10a has an imaging distance of 45 to 75 mm and a depth of field of 1.5 to 3.0 mm with value of modulation transfer function (MTF) of 30% or more at a spatial frequency of 6 lp/mm.