Xerox Corporation

Xerox Parc

University of Colorado

David A Jared

David Kalman Biegelsen

Warren Bruce Jackson

Richard G Stearns

David L Hecht

L Noah Flores

Robert Anthony Street

Steven E Ready

Lars-Erik Swartz

Kenneth H P Chang

Xiaodong Wu

Sumit Basu

Richard L Weisfield

W Glen Petrie

Kristina T Johnson

Richard M Turner

A method of decoding a plurality of glyphs comprising the steps of scanning a group of glyphs to form image data for expected glyph locations, assigning for each location a first value indicative of the likelihood that location contains a glyph in a first state, assigning for each location a second value indicative of the likelihood that location contains a glyph in a second state, determining the difference between the first and second values for each potential glyph location, establishing a distribution analysis of the determined differences and using that distribution analysis at least in part to control decoding of the plurality of glyphs.

Use of correlation histograms for improved glyph decoding

An apparatus for imaging books or other bound documents which includes a cradle for supporting a book and an optical system positioned above the cradle. The optical system is mounted for movement along a vertical axis toward and away from the cradle. It includes an upper portion supporting a camera and mirror arrangement and a lower portion comprising a platen assembly. The upper and lower portions are mounted for independent movement along the vertical axis over a first range of travel remote from the cradle, and are coupled for movement as a single unit over a second range of travel, toward and proximate to the cradle. When the upper and lower portions are coupled, the optical system has an optical path of a predetermined length extending from the platen surface, through the mirror arrangement and through the camera.

Bound document imager

A user interface is implemented using visual indicia and a background for the visual indicia that encodes address information. The background appears visually as a stipple pattern, but is implemented using glyphs which form an address carpet that encodes address information uniquely identifying each location of the user interface. An image capture device is used to capture an area of the address carpet that is at or near visual indicia of interest to the user while selecting a location in the visual indicia. The image capture device captures the area of interest, and transmits the image area to a computer for processing. The computer first determines the proper orientation of the image, and then decodes the information encoded by the glyphs. The decoding results in an X, Y address identifying the location of the captured area in the address carpet and, by reference, the address of the selected location. Based on the address, the computer may perform an operation associated with the area.

Glyph address carpet methods and apparatus for providing location information in a multidimensional address space

A captured image includes a portion of a set of two-dimensional address codes. The portion of address codes can be decoded to determine a discrete pointer uniquely defining the portion. The captured image is first processed to determine the orientation of the portion, and then decoded based on the orientation to determine the discrete pointer. To determine the orientation of the portion, the portion is first analyzed to determine values at discrete locations within the portion. The values at each location form a matrix of binary data. The values of the matrix are then correlated to determine an orientation of the captured portion of two dimensional address codes. After determining the orientation of the portion, the values can be further analyzed to determine a discrete pointer that identifies the location of the portion within the address space defined by the two-dimensional address codes.

Methods and apparatus for robust decoding of glyph address carpets

An apparatus for imaging books or other bound volumes which includes a book supporting system and an optical system positioned above the book supporting system and mounted for movement along a vertical axis toward and away from the book support system. The book support system includes an inner platform and an outer platform with the inner platform being mounted for vertical movement relative to the outer platform. A cradle having pivotable side support plates is mounted on the inner platform, and support arms are mounted on the outer platform. The support arms are positioned so that the support plates rest thereon so that as the cradle is moved downwardly, the support arms pivot the side support plates upwardly.

Bands of predetectors (92) detect the approach of lines of glyphs (12, 14) within an image being scanned. Linear lines or arrays of glyph detectors (116, 118, 120) are sampled in accordance with the detected approach of lines of glyphs. Each detector array includes a plurality of analog glyph detectors (20, 50) which respond to the presence of glyphs with a characteristic analog output. Preferably, the glyph detectors generate a corresponding analog output of a first polarity or other characteristic in response to glyphs of a first orientation and an output of a second polarity or characteristic in response to glyphs of a second orientation. The analog signals which are characteristic of the detection of a glyph are converted into binary 1's and 0's in accordance with the polarity or other characteristic of the signals. In this manner, glyphs are detected by analog detectors and the information encoded in the glyphs is directly output as a binary signal without computer analysis of the image.

Analog glyph detector and detector arrays

A color scanner with a wedge shaped platen sequentially records opposing pages of a bound document positioned thereon using a single imaging station. The scanner includes a partially reflective mirror positioned between the wedge shaped platen. The two sides of the wedge shaped platen are illuminated with polarized light having angles orthogonal to each other. Polarized illuminators operate in combination with polarization analyzers positioned under the wedge shaped platen to sequentially image the opposing pages of the bound document. A controller insures that polarized light sources consisting of the three primary colors red, green, and blue, sequentially expose each opposing page of the bound document. The opposing pages of the bound document are focused through optics onto the single imaging station. In another embodiment, light polarized by analyzers positioned under the wedge shaped platen is filtered by a polarizer positioned in front of the focal optics before reaching the single imaging station. The controller first exposes one side of the platen and then the other to each of the three primary colors red, green, and blue. Digital representations of each primary color are combined to form a single composite image for each opposing page of the bound document. In one arrangement, the imaging station is a two-dimensional array of detectors which sense an image of a page of the bound document projected thereon. In another arrangement, the imaging station is a photoconductive belt which when exposed by the polarized light records a latent image thereon. In either arrangement, a one page imaging station records opposing pages of a bound document either electronically or on print media, one page at a time.

Apparatus and method for scanning a bound color document using a wedge

An image detection and pixel processing system includes a plurality of detector elements for receiving an image. The detector elements are subdivided into a plurality of macrodetectors, with each macrodetector constituting four or more detector elements, and with each macrodetector providing information for determining both a total light intensity value within the macrodetector and a centroid of light intensity indicative of light intensity position within the macrodetector. An image processing assembly receives information from the plurality of macrodetectors, with the image processing assembly relating a pixel and its encompassed subpixel area to each corresponding macrodetector, and further determining the total light intensity within the pixel and the centroid of light intensity within the subpixel. The image processing assembly is capable of rendering each subpixel area as an edge when magnitude of the centroid of light intensity is greater than a predetermined threshold.

Macrodetector based image conversion system

An image detection and pixel processing system includes a plurality of position sensitive detector elements arranged to receive an image. Each position sensitive detector element provides information for determining both a total light intensity value within the position sensitive detector element and a centroid of light intensity indicative of light intensity position within the position sensitive detector element. An image processing assembly receives information from the plurality of position detector elements with the image processing assembly relating a pixel and its encompassed subpixel area to each corresponding position detector element. The total light intensity within the pixel and the centroid of light intensity within the subpixel is determined, with the image processing assembly rendering each subpixel area as an edge when magnitude of the centroid of light intensity is large.

Position sensitive detector based image conversion system capable of

Pixel elements capable of imaging spatial intensity variations within themselves, and displays comprised of such elements, are described. The pixel elements include a resistance layer disposed between at least one set of electrodes. Over that resistance layer is a liquid crystal material. Over that liquid crystal material is a field electrode. In operation a voltage, whose components are referenced to the field electrode, is applied across the resistance layer. The resulting current flow induces a spatially varying electric field between the field electrode and the resistance layer. That spatially varying electric field results in a corresponding response by the liquid crystal layer which results in a spatially varying light transmission through the liquid crystal material. By varying the voltage across the resistance layer and/or the voltage applied to the field electrode varying amounts of light transmission can be achieved.

Pixel elements having resistive divider elements

A semiconductor device comprising a dual photodetector for use in an array to locate points of peak intensities incident upon the array. Each pixel in the array is comprised of a dual photodetector element. An n-type well is located within a p-substrate with highly doped p-contact areas located along the periphery of the n-well at the surface. A metal or polysilicon gate electrode covers the surface between the p-contacts and an applied gate voltage creates an inverted p-channel to form a lateral effect phototransistor. A second photodetector is formed at the junction of the n-well and p-substrate. The second photodetector from each pixel produces a current which is connected to a processing circuit to determine which pixel is the brightest above a designated threshold. All pixels above the threshold are sequentially identified. For the 'bright' pixels, photogenerated currents produced by the lateral effect phototransistors are analyzed by another processing circuit to produce the points of peak intensity within the bright pixel areas.

Growing community of inventors

Sunnyvale, CA, United States of America

David A Jared