An illumination device includes a light guide member having a first side in a main scanning direction and a second side in a sub-scanning direction and a plurality of light sources including first light emitters respectively to emit beams of light of a first color and a second light emitter to emit a beam of light of a second color different from the first color toward an inside of the light guide member via a side of the light guide member in the main scanning direction. The first light emitters are positioned in the sub-scanning direction to be symmetrical to each other.

A method and device for the optical scanning of a chromatographic sample (3), where a sample plate (2) holding the sample (3) is illuminated with light from a first illumination device (13) and the light emitted by the sample plate (2) is detected by an optical detector device (15) which detects in cell form or area form, a second illumination device (14) is preferably firstly activated in a preparation step. The sample plate (2) is displaced in a first displacement direction relative to the detector device (15), illuminated by the first illumination device (13) and a first measurement image is recorded. The sample plate (2) is displaced in a second displacement direction relative to the detector device (15), illuminated by the second illumination device (14), and a second measurement image is recorded.

An image scanner includes a controller configured to perform black data acquiring process for each color that includes, in a particular period of time, while controlling a light source to be turned off, controlling each of a plurality of light receiving elements to read an image of an object and transmit read data of the object to a shift register, and in a specific period of time next to the particular period of time, controlling the light source to emit light of a color different from the particular color, and controlling the shift register to output a plurality of pieces of image data of the object as a plurality of pieces of black data for the particular color, the plurality of pieces of image data corresponding to the plurality of pieces of read data of the object transmitted by the plurality of light receiving elements, respectively.

A monochrome imager used in such systems as a scanner can detect watermarks that have been encoded in the color space or chrominance. Such watermarks are called chroma watermarks and are considered more reliable than the traditional classic watermarks, which are encoded based on luminance. The monochrome imager detects the chroma watermark, which has been illuminated with ambient white light from a blue light emitting diode (LED) coated with phosphor.

An exposure device includes a first light emitting element substrate including a plurality of first light emitting elements arranged at an arrangement interval T in a longitudinal direction, and a second light emitting element substrate including a part in the longitudinal direction that overlaps with a part of the first light receiving element substrate so as to form an overlapping region. The first and second light emitting element substrates are shifted from each other in a direction perpendicular to the longitudinal direction. The second light emitting element substrate includes a plurality of second light emitting elements arranged in the longitudinal direction. The second light emitting elements are arranged at the arrangement interval T at least outside the overlapping region. When an interval between two of the second light emitting elements of the second light emitting element substrate disposed in the overlapping region is expressed as a specified interval TS, the specified interval TS and the arrangement interval T satisfy:

T≦TS≦2T.

An estimated image data calculator is configured to calculate, as estimated image data, for each of image data of respective colors outputted from an imaging element, on the basis of a pixel value of a first pixel on one of two lines adjacent to each other in the image data, and a pixel value of a second pixel on the other of the two lines and adjacent to the first pixel, image data of a non-reading region between a reading region in a document corresponding to the one of the two lines and a reading region in the document corresponding to the other of the two lines. A pixel value correcting unit is configured to correct at least one of the pixel value of the first pixel and the pixel value of the second pixel on the basis of the estimated image data.

An optical print head for illuminating an image carrier facing the optical print head includes: a substrate on which a light emitting element array is mounted; a lens array for focusing light emitted from the light emitting element array onto the image carrier; a holder holding the substrate and the lens array; and at least one spacer member, disposed on the holder, for maintaining a predetermined distance between the lens array and the image carrier, the at least one spacer member being made of curable resin that is cured under a predetermined condition or fixed to the holder with curable adhesive that is cured under a predetermined condition.

In an image reading device, a controller is configured to perform: calculating a ratio between first and second reference data as evaluation data; designating a target light receiving element from a plurality of light receiving elements one by one sequentially; calculating average evaluation data of the target light receiving element by averaging the evaluation data of a second number of light receiving elements located at positions apart every predetermined distance equal to a length of a first number of consecutively arranged light receiving elements; setting an evaluation range of the target light receiving element by adding/subtracting a predetermined value to/from the average evaluation data; determining whether the evaluation data falls within the evaluation range; in response to determining that the evaluation data is out of the evaluation range, revising the second reference data of the target light receiving element; and generating correction data using the second reference data after revision.

A linear image scanner capable of digitizing three-dimensional surfaces according to the photometric stereo technique has a linear type imaging sensor, a scanning plane, an optical system, an optical axis, a scan line, a lighting system with at least four independently controllable light sources arranged so that each light source enlighten the scan line from a different direction. At least two first light sources are arranged symmetrically respect to the vision plane and at least two second light sources are arranged symmetrically respect to the moving plane and so that the at least two first and two second light sources radiate the scan line from at least four different directions with uniform light intensity and uniform incident angles of the light sources over the entire length of the scan line. A scanning method is also described.

The present disclosure relates generally to digital watermarking for retail product packaging. A digital watermark can be carried in different color channels, and at with different signal polarities. Detection can utilize different illumination sources to highlight signal in one or more channels.