Xerox Corporation

Apple Inc.

Gary K Starkweather

David Kalman Biegelsen

James Charles Zesch

John C Urbach

Leonard C DeBenedictis

John C Dalton

A method and apparatus for improving the quality of images captured by inexpensive scanning devices is described. After an initial scan of the image to be captured is performed, at least two additional scans are performed, one at an exposure level much greater than that used in the first scan and one at an exposure level much lower than that used in the first scan. After all three scans are complete, a composite stored image is formed using the gray scale values generated by the overexposed scan for darker areas of the image, the gray scale level generated by the underexposed scan for the lighter portions of the image, and, for those areas between the extremes, using the gray scale levels produced by the first scan. An apparatus is also described for performing these scans and selecting and combining the requisite data.

Method and apparatus for improved image generation using scanning devices

A color calibration system comprises a processor for receiving and transmitting data. A first sensor coupled to the processor detects emissive color images for providing first color sampling data to the processor. A second sensor coupled to the processor detects reflective color images for providing second color sampling data to the processor. A color output device coupled to the processor is calibrated in response to data generated by at least one of the first and second sensors.

Method and apparatus for calibrating and adjusting a color imaging system

An error reducing raster scan method for a raster scan device having multiple simultaneous scan lines, the method including the steps of separating scan lines to be placed adjacent to each other into different scan groups, so that no two scan lines to be placed adjacent to each other are in the same scan group, and a scanning a set of scan lines from a different one of the scan groups on each scan across the area.

Error reducing raster scan method

A single facet wobble free light scanner which eliminates the effects of wobble caused by bearing inaccuracies or other mechanical factors. A pentaprism, pentamirror, right angle prism or right angle mirror monogon 30 is rotated about an axis passing through its sides and through the axis of the applied light beam 8. By reflections off of two mirrored surfaces 22, 24, the output light beam 28 creates a plane of light. When, or if, the pentaprism 30 wobbles about the rotational axis, the effects of the wobble are eliminated because via the internal reflections of the pentaprism, the output light beam 28a is parallel to the original output light beam 28, the parallel light beams 28,28a being focused onto the scan surface by external optics 70.

Single facet wobble free scanner

A single facet wobble free light scanner which eliminates the effects of wobble caused by bearing inaccuracies or other mechanical factors. A pentaprism, pantamirror, right angle prism or right angle mirror monogon 30 is rotated about an axis passing through its sides and through the axis of the applied light beam 8. By reflections off of two mirrored surfaces 22, 24, the output light beam 28 creates a plane of light. When, or if, the pentaprism 30 wobbles about the rotational axis, the effects of the wobble are eliminated because via the internal reflections of the pentaprism, the output light beam 28a is parallel to the original output light beam 28, the parallel light beams 28, 28a being focused onto the scan surface by external optics 70.

Method and apparatus for improving the efficiency of laser scanning systems using a multifaceted rotating polygon or pyramid as the scanner. In particular, a beam of light, such as that generated by a laser beam, is directed onto a first facet of the scanner. This beam is expanded and reflected back to the same facet or any other facet on the scanner by optical means positioned adjacent the scanner so that the beam is caused to follow the facet of the scanner upon which the beam is reflected during a complete scan and to shift to the next facet for the following scan.

Self tracking laser scanning apparatus

An acousto-optic device including an acousto-optic medium having a plurality of closely spaced transducers bonded thereto in a linear array. A signal of the same frequency is supplied to those transducers which are to diffract out or deflect elemental portions of a light beam incident upon the acousto-optic medium to thereby provide a plurality of light spots which can be written in parallel.

Linear array modulator

A flying spot scanning system is provided by utilizing reflected light from a multifaceted rotating polygon which is then directed to the scanned medium. A light source illuminates at least one of the facets of the polygon during each scanning cycle to provide a scanning beam of light. In each scanning cycle, information is transmitted to the scanned medium by modulating the light from the light source in accordance with a video signal. A first cylindrical lens is employed in convolution with other optical elements to focus the scanning beam to a spot in a focal plane at the surface of the medium. Start of scan detection is provided for the synchronization of the scanning cycles by means apart from the scan width on the medium. A portion of the beam at the start of scan position is deflected to impinge upon a second cylindrical lens which focuses the deflected beam to a spot received by a detector element.

Flying spot scanner with scan detection

An optical flying spot scanner having a lens array positioned between a scan line and a detector array and inclined at an angle to the axis of the scan line. Each of the lenses of the lens array has a coordinate position in a plane parallel to the scan line related to a particular segment of the scan line such that the information content of each segment of the scan line is transmitted to a different one of the tiered detectors of the detector array.

Twisting geometry scanner

A flying spot scanning system is provided by utilizing reflected light from a multifaceted rotating polygon which is then directed to the scanned medium. A light source illuminates a portion of the mirrored sides of the polygon during each scanning cycle, to provide a desired sequence of spot scanning. In each scanning cycle, information is transmitted to the scanned medium by modulating the light from the light source in accordance with a video signal. An optical convolution of elements is selected in combination with the light source to assure a uniform spot size throughout the scan width on the scanned medium. One of these elements is a cylindrical lens placed in the optical path between the polygon and the scanned medium for allowing a wide variance in runout tolerance of the scanning system.

Flying spot scanner with runout correction

A flying spot scanning system is provided by utilizing reflected light from a multifaceted rotating polygon which is then directed to the scanned medium. A light source illuminates at least two contiguous facets of the polygon during each scanning cycle, to provide the desired sequence of spot scanning. To assure a uniform spot size at the scanned medium, an optical convolution of elements is selected in combination with the light source such that an adequate depth of focus at the medium is assured. In each scanning cycle, information is transmitted to the scanned medium by modulating the light from the light source in accordance with a video signal.

Flying spot scanner

An apparatus which can function either in a copier mode or in a raster scan mode. A first unit of the apparatus, containing elements to produce an information modulated, scanning light beam, is movably mounted upon a second unit of the apparatus, containing optical elements for directing light upon a photosensitive medium, such that the movable unit can be located clear of the document supporting platen of the second unit to provide copier operation or can be located immediately adjacent the platen of the second unit to provide raster scanning operation. Optical means are provided in the movable unit to provide light focusing capabilities for the raster scan mode of operation.

Copier/raster scan apparatus

A scanning system is employed which utilizes an unmodulated beam for reading a document (original size or microfilm) and utilizes a modulated beam for printing an image (original size or a microimage) which beams both originate from the same laser source and strike the same facets of a polygon scanner at the same location or at spaced vertically aligned locations.

Multifunction scanning system

A flying spot scanning system is provided by utilizing reflected light from a multifaceted rotating polygon which is then directed to the scanned medium. A light source illuminates a portion of the mirrored sides of the polygon during each scanning cycle, to provide a desired sequence of spot scanning. In each scanning cycle, information is transmitted to the scanned medium by modulating the light from the light source in accordance with a video signal. An optical convolution of elements including at least two lenses having power in one optical plane and substantially no power in the other plane, is provided in combination with the polygon. One of these lenses is placed in the optical path between the polygon and the scanned medium with its power plane substantially parallel to the axis of rotation of the polygon for allowing a wide variance in runout tolerance of the scanning system. The other lens is placed in the optical path between the light source and the polygon with its power plane substantially perpendicular to the axis of rotation of the polygon.

Flying spot scanner with plural lens correction

A flat field scanning system is disclosed which has the following characteristics: (a) a stationary lens is located between a scanning mirror and a medium; (b) the mirror is moved linearly for scanning; (c) at the start of scan, a beam is directed from or received by the mirror substantially on axis of the lens; (d) the beam distance from the object plane of the lens to the lens and from the lens to the image plane of the lens always increases from the start of scan to the end of scan; and (e) during movement of the mirror, the mirror is pivoted to continue to reflect the beam through or receive the beam from the center of the lens. Linear movements are utilized in the scanning system eliminating the use of intricate cam surfaces. In one embodiment, the medium is either a recording medium or a document to be read by scanning and is located at the image plane of the lens. The scanning mirror is located between the object plane of the lens and the lens and scans the beam to the medium. A polygon scanner scans a beam onto the medium via the scanning mirror in an 'X' direction while the scanning mirror provides scanning of the beam in a 'Y' direction. In a modification of the above embodiment, an oscillating mini-scan mirror is located between the scanning mirror and the object plane and scans the beam to the scanning mirror in the 'Y' direction. The scanning mirror is stationary allowing the mini-scan mirror to 'Y' scan only a portion of the medium, which is usually 20-32 'X' scan lines or one text line. The scanning mirror is moved one text line at a time to allow mini 'Y' scanning of the whole medium. In another embodiment, the medium is a document illuminated by flood lamps and is positioned on the object plane of the lens. The scanning mirror is located between the image plane of the lens and the lens. A recording medium is located at the image plane of the lens to receive the image on the document.

Growing community of inventors

Saratoga, CA, United States of America

Gary K Starkweather