Abstract: A two camera over-the-belt optical character recognition (OCR) system for reading the destination addresses on parcels carried on a conveyor belt. The parcels bear an orientation defining fluorescent ink fiduciary mark that is typically stamped on the parcel in the same area as the destination address. The fiduciary mark is located approximately in the center of the destination address block and oriented in the same direction as the underlying destination address. The first camera, a low resolution CCD camera, captures an image of the fiduciary mark. A host computer stores an image of the fiduciary mark, determines the position and orientation of the fiduciary mark, and defines a region of interest about the fiduciary mark. The second camera, a high resolution CCD camera, captures a grey-scale image of the conveyor and the parcels carried on the conveyor.

Abstract: The optical path between a camera positioned above a conveyor and objects traveling on the conveyor is adjusted by moving a plurality of mirrors that at least partially define the optical path. The mirrors are manipulated as a function of the height of the objects so that the length of the optical path between each object and the camera is generally the same. The plurality of movable mirrors are equidistant from and arranged about a central point. The plurality of movable mirrors are contemporaneously moved toward and away from the central point to equalize the length of the optical path. Each of the movable mirrors translates along a different travel path. The travel paths are non-parallel. The plurality of movable mirrors are arranged so that the optical path includes a plurality of segments, and at least one intersection is defined between the segments distant from the movable mirrors.

Abstract: An unsymmetrical elliptical reflector for spatial illumination. The invention includes a novel reflector and a novel illumination system including the novel reflector. The novel reflector includes first and second, non-symmetrical, elliptical elongate reflector surfaces. The eccentricities of the first and second reflector surfaces are different such that they have common first foci and different conjugate foci. The novel illumination system incorporates the novel reflector and provides intense, focused illumination at two foci positioned at two heights above a conveyor surface. The illumination intensity between the two foci is sufficiently intense to provide adequate illumination of encoded labels carried on package surfaces at heights between the two foci.

Abstract: A system for reading package information includes an imaging system and a label decoding system. The imaging system captures an image of a package surface that includes a machine readable code such as a bar code and an alphanumeric destination address. The label decoding system locates and decodes the machine readable code and uses OCR techniques to read the destination address. The destination address is validated by comparing the decoded address to a database of valid addresses. If the decoded address is invalid, an image of the destination address is displayed on a workstation and an operator enters the correct address. The system forms a unified package record by combining the decoded bar code data and the correct destination address data. The unified package record is used for subsequently sorting and tracking the package and is stored in a database and applied to a label that is affixed to the package.

Abstract: Fiduciary mark detection system usable with an over-the-belt optical character recognition (OCR) reader for ascertaining the position and orientation of text within the destination address on parcels moving along a conveyor, comprising charged coupled device (CCD) array, analog-to-digital (A/D) converter, general purpose computer, and software program. Image processing software program comprising projection histograms, convolution filtering, correlation, radial variance, first moments of inertia, edge image analysis, Hough method, detection confidence testing. Orientation defining mark comprising fluorescent ink placed approximately in the center of the destination address block on a parcel is non obstructive of the underlying text and may be affixed to parcel any time prior to scanning. Fiduciary mark comprising two circles of different diameter oriented such that a vector from the center of large circle to center of small circle is oriented in the same direction as underlying text.

Abstract: An optical system for adjusting the optical path between a detector and an object, such as an information-encoded label affixed to a package. The optical system comprises a pair of movable mirrors and an array of fixed mirrors. One of the movable mirrors is positionable to direct an image reflected from the object to any one of the array of fixed mirrors. The other of the movable mirrors is positionable to direct the image reflected by the fixed mirror to the detector. The positions of the movable mirrors are adjusted responsive to variations in the measured height of different objects.

Abstract: An apparatus for providing uniform illumination to a surface includes a chamber defined by a wall, the wall having an opaque wall portion and a partially transparent wall portion. A light source such as a flash lamp, is mounted in the chamber. The interior surface of the chamber wall is light-reflective. The partially transparent wall portion has transparent apertures which permit light to exit the light chamber. The partially transparent wall portion has a first section with a first average transparency and a second section with a second average transparency. In operation, the apparatus completely covers a target surface while light generated by the light source either directly exits the light chamber through the transparent apertures or is reflected off the reflective interior surfaces of the light chamber before exiting the light chamber through the transparent apertures, uniformly illuminating the target surface.

Abstract: A method and apparatus for synchronizing two signals having a phase relationship and originating from transmission lines having unknown and differing skew includes a variable delay element with adjustable delay responsive to an applied biasing voltage inserted into one of the transmission lines. The phases of the signals are compared and phase error information generated. The error information is thereafter converted to a biasing voltage which is applied to the variable delay element. As a result, the delay characteristic of the one transmission line is adjusted to synchronize the signals.

Abstract: An electronically variable delay line having adjustable delay and bandwidth characteristics is provided. A varactor diode functioning as a variable controlled capacitance is coupled between a signal conductor and a ground reference conductor, thereby segmenting the signal conductor into two, individual smaller segments of conductor which function as fixed inductances. The delay characteristic of the line is adjusted by varying the varactor's biasing voltage which, in turn, varies the varactor's capacitance. A staggered termination technique is implemented to stabilize the insertion loss characteristics of the delay line.