Xerox Corporation

Pierre A Lavallee

Peter A Crean

Martin A Agulnek

Jagdish C Tandon

Martin Edward Banton

Wayne A Buchar

James C Stoffel

Joseph J Daniele

Mehdi N Araghi

Kwok L Yip

Keith Allan Nau

Sidney W Marshall

Ronald L Antos

An image scanner apparatus scans a document and provides image data in digital form representing the scanned document. The compression apparatus detects characteristics of the image data and compresses the image data using parallel compressors, each employing a different encoding scheme. The apparatus then selects compressed image data encoded by one of the compressors in accordance with the detected characteristics and stores the selected data.

Apparatus and method for selecting encoding schemes based upon image content

In an input scanner provided with a document input, a sheet feeding path for transporting documents to a scanning station and to a document output; a scanning station having at least a first scanning element, normally fixed in position relative to the sheet feeding path, and supporting a full width array of photosensitive sensors with a coresponding optical arrangement for directing light from the document to the sensors, there is provided an arrangement for bringing the optical arrangement and sensors of the scanning element to a calibration sensing position for detection of a calibration target provided in a fixed position within the input scanner, while retaining the scanning element at a fixed position relative to the sheet feeding path. The arrangement for moving the optical arrangement and sensors of the scanning element to a calibration sensing position for detection of a calibration target may also provide movement to a service position to allow access to the sensors from a position exterior to the input scanner without disassembly of the scanning head from the input scanner.

Fixed full width array scan head calibration apparatus

A linear image sensor array with a row of photodiodes and a transfer circuit for each photodiode, the circuit having a pair of transistors for two stage transfer of the image signal charge from the photodiode to the gate of one transistor of a two transistor source follower, a transistor for applying a bias charge to the photodiode, a multiplexing transistor for connecting the source follower output to an output line, a reset transistor for resetting the source follower, and clock signals for operating the transfer circuits in succession to serially output image signals to the output line.

Image sensor array with two stage transfer

A full width opto-mechanical modulator comprised of a silicon chip have dual rows or arrays of flexible finger-like reflectors disposed thereon in staggered facing relationship to one another. The reflectors, the surface of which is highly reflective, bend in response to the application of a predetermined potential. The modulator is placed in the path of a beam of high intensity light, and potentials applied to selected reflectors in accordance with an image signal input cause the modulator to reflect light striking the individual reflectors in either an exposure path or against a beam stop.

Multiple array full width electro mechanical modulator

A raster scanner with laser for generating a scanning beam and compact, folded optical system for transmitting the beam to the object to be scanned. The optical system includes a first mirror for guiding the laser beam forward along a downwardly inclined slope to the modulator, a second mirror below the modulator for intercepting the beam from the modulator and folding the intercepted beam to guide the beam backwards along a horizontal plane to a third mirror which folds the beam and guides the beam forward along an upwardly inclined slope against the mirrored facets of a rotating polygon, the polygon scanning the beam through a preset scan arc and returning the beam via a focusing lens to the third mirror, the third mirror folding the scan beam and guiding the scan beam forward, and a fourth mirror for intercepting the scan beam and guiding the beam to the object to be scanned.

Double pass scanning system

A multiple mode image processing apparatus and method. The apparatus, in a copy mode, processes copies xerographically. In a write mode, images derived from image signals are written on the apparatus photoreceptor by a raster scanner, and in a read mode, the raster scanner scans images developed on the photoreceptor to produce image signals representative thereof. A multiple speed drive is provided for the photoreceptor to move the photoreceptor at a high speed when processing copies xerographically and at a lower speed compatible with the data transmission rate for image signals when writing or reading images.

Multiple mode image processing apparatus and method

An image signal processing architecture for image filtering using high and low image resolution scanning arrays to scan a document original. The image pixels produced by the high resolution scanning array are analyzed to determine the presence of high frequency halftone image pixels. Where high frequency halftone image pixels are not found, the image pixels are filtered to enhance the signal content and thereafter thresholded adaptively. Where high frequency halftone image pixels are determined to be present, the pixels produced by the low resolution array are descreened and thereafter rescreened at different screen frequency. A control switch permits the user to process continuous tone images directly. In the principal embodiment, both high and low resolution scanning arrays are disposed on a common substrate to form a unitary structure. In a second embodiment, separate scanning arrays are spaced at preset distances from the object plane to provide the requisite high and low image reading resolutions. To correlate image resolutions between the scanning arrays interpolation means are provided to interpolate additional image pixels in the output of the low resolution array.

Multi-resolution image signal processing apparatus and method

A line scanning apparatus employing a multiplicity of linear arrays, the linear extent of which is less than the length of the scan line. To permit an entire line to be covered, the arrays are offset from one another in the direction of scan with adjoining array ends overlapped. To correct for the misalignment and redundancy introduced, the image data from the arrays is buffered until a line is completed when readout, is initiated. During readout, cross over from one array to the next is effected within the overlapped areas and the redundant data discarded.

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Penfield, NY, United States of America

Pierre A Lavallee