Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2000-09-21
2004-03-16
Le, Thien M. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S462250, C235S462010
Reexamination Certificate
active
06705526
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates generally to an automated tunnel-type laser scanning package identification and measuring system arranged about a high-speed conveyor structure used in diverse package routing and transport applications, and also a method of identifying and measuring packages labeled with bar code symbols.
2. Brief Description of the Prior Art
In many environments, there is a great need to automatically identify and measure objects (e.g. packages, parcels, products, luggage, etc.) as they are transported along a conveyor structure. While over-the-head laser scanning systems are effective in scanning upwardly-facing bar codes on conveyed objects, there are many applications where it is not practical or otherwise feasible to ensure that bar code labels are upwardly-facing during transportation under the scanning station.
Various types of “tunnel” scanning systems have been proposed so that bar codes can be scanned independently of their orientation within scanning volume of the system. One such prior art tunnel scanning system is disclosed in U.S. Pat. No. 5,019,714 to Knowles. In this prior art scanning system, a plurality of single scanline scanners are orientated about a conveyor structure in order to provide a limited degree of omni-directional scanning within the “tunnel-like” scanning environment. Notably, however, prior art tunnel scanning systems, including the system disclosed in U.S. Pat. No. 5,019,714, are incapable of scanning bar code systems in a true omni-directional sense, i.e. independent of the direction that the bar code faces as it is transported along the conveyor structure. At best, prior art scanning systems provide omni-directional scanning in the plane of the conveyor belt or in portions of planes orthogonal thereto. However, true omnidirectional scanning along the principal planes of a large 3-D scanning volume has not been hitherto possible.
Also, while numerous systems have been proposed for automatically identifying and measuring the dimensions and weight of packages along a high-speed conveyor, prior art systems have been very difficult to manufacture, maintain, and operate in a reliable manner without the use of human supervision.
Thus, there is a great need in the art for an improved tunnel-type automated laser scanning package identification/measuring system and a method of identifying and measuring packages transported along a high-speed conveyor system, while avoiding the shortcomings and drawbacks of prior art scanning systems and methodologies.
OBJECTS AND SUMMARY OF THE PRESENT INVENTION
Accordingly, a primary object of the present invention is to provide a novel tunnel-type automated package identification and measuring system that is free of the shortcomings and drawbacks of prior art tunnel-type laser scanning systems and methodologies.
Another object of the present invention is to provide a fully automated package identification and measuring system, wherein an omni-directional laser scanning tunnel is used to read bar codes on packages entering the tunnel, while a package dimensioning subsystem is used to capture information about the package prior to entry into the tunnel.
Another object of the present invention is to provide such an automated package identification and measuring system, wherein Laser Detecting And Ranging (LADAR-based) scanning methods are used to capture two-dimensional range data maps of the space above a conveyor belt structure, and two dimensional image contour tracing methods are used to extract package dimension data therefrom.
Another object of the present invention is to provide a fully automated package identification and measuring system, wherein the package dimensioning subsystem is realized as a LADAR-based package imaging and dimensioning unit (i.e. subsystem) supported above the conveyor belt structure of the system.
Another object of the present invention is to provide such an automated package identification and measuring system, wherein the LADAR-based imaging and dimensioning subsystem produces a synchronized amplitude-modulated laser beam that is automatically scanned across the width of the conveyor belt structure and, during each scan thereacross, detects and processes the reflected laser beam in order to capture a row of raw range (and optionally reflection-intensity) information that is referenced with respect to a polar-type coordinate system symbolically-embedded within the LASAR-based imaging and dimensioning subsystem.
Another object of the present invention is to provide such an automated package identification and measuring subsystem, wherein the rows of range data captured by the LADAR-based imaging and dimensioning subsystem are continuously loaded into a preprocessing data buffer, one row at a time, and processed in real-time using window-type convolution kernels that smooth and edge-detect the raw range data and thus improve its quality for subsequent dimension data extraction operations.
Another object of the present invention is to provide such an automated package identification and measuring subsystem, wherein the LADAR-based imaging and dimensioning subsystem automatically subtracts detected background information (including noise) from the continuously updated range data map as to accommodate for changing environmental conditions and enable high system performance independent of background lighting conditions.
Another object of the present invention is to provide such an automated package identification and measuring subsystem, wherein the LADAR-based imaging and dimensioning subsystem automatically buffers consecutively captured rows of smoothed/edge-detected range data to provide a range data map of the space above the conveyor belt, and employs two-dimensional image contour tracing techniques to detect image contours within the buffered range data map, indicative of packages being transported through the laser scanning tunnel system.
Another object of the present invention is to provide such an automated package identification and measuring subsystem, wherein the LADAR-based imaging and dimensioning subsystem automatically processes the indices (m,n) of the computed contours in order to detect vertices associated with polygonal-shaped objects extracted from the range data map, which are representative of packages or like objects being transported through the laser scanning tunnel system.
Another object of the present invention is to provide such an automated package identification and measuring subsystem, wherein the LADAR-based imaging and dimensioning subsystem automatically processes the m and n indices of the detected vertices associated with the computed contours in order to detect candidates for corner points associated with the corners of a particular package being transported through the laser scanning tunnel system.
Another object of the present invention is to provide such an automated package identification and measuring subsystem, wherein the LADAR-based imaging and dimensioning subsystem automatically processes the m and n indices of detected corner point candidates in order to reduce those corner point candidates down to those most likely to be the corners of a regular-shaped polygonal object (e.g. six sided box).
Another object of the present invention is to provide such an automated package identification and measuring subsystem, wherein the LADAR-based imaging and dimensioning subsystem automatically processes the m and n indices of the corner points extracted from the range data map in order to compute the surface area of the package represented by the contours traced therein.
Another object of the present invention is to provide such an automated package identification and measuring subsystem, wherein the LADAR-based imaging and dimensioning subsystem automatically processes the m and n indices of the corner points extracted from the range data map in order to compute the x, y and z coordinates corresponding to the corners of the package represented by the contours traced therein, referenced rel
Au Ka Man
Blake Robert E.
Dickson LeRoy
Germaine Gennady
Good Timothy A.
Le Thien M.
Metrologic Instruments Inc.
Perkowski Esq. P.C. Thomas J.
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