Data processing: measuring – calibrating – or testing – Measurement system – Dimensional determination
Reexamination Certificate
2000-05-08
2002-08-27
Assouad, Patrick (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system
Dimensional determination
C356S389000, C250S559220
Reexamination Certificate
active
06442503
ABSTRACT:
DESCRIPTION
BACKGROUND OF THE INVENTION
This invention relates to a process for measuring the volume of an object, and to an apparatus implementing the process.
A problem shared by many segments of industry and trade is that of assessing the volume of an object. In particular, the supply and shipment of goods demand that the volume of packages be measured in an automated fashion to provide an element of information which is valuable to the conduction of both the storehouse premises and the carrier means.
Storehouse premises and carriers generally handle objects according to their weight, and to one or more of their linear dimensions regarded as most significant. This handling style is, therefore, approximative and surely less than fully satisfactory.
SUMMARY OF THE INVENTION
Accordingly, a first aspect of the invention relates to a process for measuring the volume of an object, characterized in that a means of reading an optical code from the object is used.
Optical codes mean here graphical sequences wherein elements of information are recorded in a coded form which can be read by appropriate reading instruments. Examples of optical codes include bar codes, two-dimensional codes, color codes, etc.
In fact, in typical situations where the volume of an object is to be measured (such as package handling through a distribution system or storehouses and the like), an apparatus for reading optical codes would be already provided. The apparatus is inclusive of a set of components (laser units, signal processing units, and processing/storage units) which can be adapted to measure the volume of an object at the expense of a few minor changes and alterations.
Suitably, the optical code reading means comprises a laser scanner, preferably a modulated light scanner, operative to measure the range or distance of a spotted point. A scanner of this type is described, for instance, in U.S. Pat. No. 5,483,051 by this Applicant.
Advantageously, the means of reading may comprise a CCD reader.
The volume may be measured by any of a number of different processes which form the subject matter of specific patent applications filed by the Applicant on this same date. Only the basic features of these processes will be reviewed herein, and for a more detailed explanation, reference can be had to such patent applications.
According to a first of such processes, a volume measurement involves the following steps:
a) placing the object onto a bearing surface;
b) defining a feed direction for the object on the bearing surface;
c) defining a scan plane, intersecting the plane of the bearing surface along a scan base line which lies transverse to the feed direction, with a laser beam from a scanner that overlies the bearing surface being arranged to act in the scan plane;
d) moving the object across the bearing surface along the feed direction, relative to the scan plane, until the scan plane will intersect the object;
e) obtaining the height, above the bearing surface, of n points of measurement contained in a top face of the object and the scan plane;
f) defining a stipulated height as a function of the measured heights of two successive points of measurement;
g) obtaining the plan position on the bearing surface of the n points of measurement;
h) defining a stipulated base as a function of the plan positions on the bearing surface of each pair of adjacent points of measurement;
i) computing a stipulated area element, vertical to the bearing surface, for each pair of adjacent points of measurement, as by multiplying the stipulated base by the stipulated height;
j) computing a stipulated area as the combined sum of the stipulated area elements computed;
k) moving the object relative to the scan plane a predetermined feed distance along a feed direction across the bearing surface;
l) defining a stipulated thickness as a function of the feed distance;
m) computing a volume element by multiplying the stipulated area by the stipulated thickness;
n) repeating steps e) to m) above until the entire object is scanned;
o) computing the object volume as the combined sum of all the volume elements.
The term top face is here a generic one, it encompassing any surface seen by the laser scanner placed above the bearing surface. In particular, even a sloping side surface may be taken to be the top face, whose slope is an upward taper angle of the object as referred to its rest position on the bearing surface.
The movement of step d) above should be understood as a relative movement. Thus, it may either be a movement of the object relative to a fixed scan plane, or a movement of the scan plane relative to an object held stationary, or both.
According to a second of such processes, the volume measurement involves the following steps:
placing the object onto a bearing surface;
defining a feed direction for the object on the bearing surface;
defining a scan plane, intersecting the plane of the bearing surface along a scan base line which lies transverse to the feed direction, with a laser beam from a scanner that overlies the bearing surface being arranged to act in the scan plane;
defining a fixed Cartesian reference system having a longitudinal axis (y) along the feed direction, a transverse axis (x) orthogonal to the longitudinal axis (y), and a vertical axis (z) orthogonal to the plane of the bearing surface;
moving the object across the bearing- surface, along the feed direction, relative to the scan plane until the scan plane will intersect the object;
effecting a scan sweep across the object in the scan plane by means of the scanner;
reckoning and storing a set of triads of coordinates (x, y, z) of n points of measurement of the object swept by the laser beam in the scan plane;
moving the object relative to the scan plane through a feed distance in the feed direction equal to a predetermined longitudinal resolution (L);
repeating the three last-mentioned steps until the entire object is scanned;
establishing a set of standard values (x″) for the transverse coordinate separated by a value equal to a predetermined transverse resolution (T);
constructing, for each scan sweep, a set of equivalent triads (x″, y″, z″) representing equivalent points, wherein the values of the transverse coordinate (x″) are equal to the values of the standard set, and the values of the longitudinal coordinate (y″) and the vertical coordinate (z″) are respectively functions of the values of the reckoned longitudinal and vertical coordinates (y, z);
computing the volume included between the bearing surface (x, y) and the surface defined by those points which have equivalent coordinates (x″, y″, z″).
Here again, the movement of the object across the bearing surface in the feed direction, with respect to the scan plane, should be understood as a relative movement.
According to a third of such processes, the volume measurement involves the following steps:
placing the object onto a bearing surface;
defining a feed direction for the object on the bearing surface;
defining a scan plane, intersecting the plane of the bearing surface along a scan base line which lies transverse to the feed direction, with at least one laser beam from the scanner that overlies the bearing surface being arranged to act in the scan plane;
defining a read plane intersecting the plane of the bearing surface along a read base line which lies transverse to the feed direction, light beams being active in the read plane which are picked up by the CCD reader located above the bearing surface;
moving the object across the bearing surface, along the feed direction, relative to the scan and read planes such that the object will cross these planes;
effecting a series of scan sweeps across the object in the scan plane with the laser beam, such that at each scan sweep, the positions of n points of measurement defining the object outline as spotted by the laser beam are reckoned;
effecting a corresponding series of readings of the object by means of the CCD reader to reckon, at each reading, the maximum width of the object out
Assouad Patrick
Datalogic S.p.A.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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