HK1132323B - Device for measuring package size - Google Patents

Description

Device for measuring package dimensions

Technical Field

The present invention relates generally to the handling of packages or other articles for shipping. More particularly, the present invention relates to an apparatus and method for determining relevant physical parameters of a package.

Background

Many courier companies provide the service of shipping packages to their customers. The courier collects the fee for distributing the package to the customer's designated destination. Typically, the cost is based on one or more of the following: (1) the size of the package, (2) the weight of the package, (3) the destination of the package, (4) the time at which the package must be shipped.

There are problems in determining the appropriate cost for shipping the package. In some cases, the volume of the package is a limiting factor, especially for goods shipped by overnight express. In other cases, the weight of the package may be the limiting factor. There is a need for a method of measuring physical parameters of such packages in order to estimate the appropriate shipping costs for the customer.

For large courier companies, these costs need to be determined for a large number of packages. Large courier companies often have a central sorting station. In these sorting stations, the packages collected from the customers are processed for transport to the customer's designated destination. Typically, in such a case, the packages will be unloaded onto a conveyor belt, and the volume and/or weight of each package will be determined as the package moves along the conveyor belt. The customer is typically then automatically billed. Such a system is disclosed in published U.S. patent application No. 20030225712.

In other cases, there is a smaller number of packages, and shipping costs are typically obtained when the user provides the package for shipping. For example, there are many companies that provide private mailbox services and the like in a storefront environment. Often, such companies also provide courier services. The customer enters the store with the package and immediately measures the size and/or weight of the package to determine the shipping cost. In this case, the measuring device used generally requires the user to place the package on the measuring platform.

Us patent 4,773,029 ("claison") discloses a measuring device for measuring the three-dimensional dimensions of articles carried by a conveyor belt. The height of an article is measured by pairs of transmitters and receivers positioned on opposite sides of the conveyor belt and aimed through the conveyor belt. The width of the package is measured by pairs of emitters and receivers, arranged above the conveyor belt and below the surface of the conveyor belt, between its two parts. The length of the device is measured by calculation using the velocity of the articles on the conveyor belt.

The rows of transmitters and receivers are made up of modules. Thus, if the size of the article of interest is small, fewer modules may be used to create a row of transmitters and receivers. However, if the article is larger, more transmitters and receivers are required for measuring its size, and then more modules can be used to extend the size of any set of transmitters and receivers.

The transmitter and receiver operate in pairs. Thus, if a particular receiver does not receive its signal from a particular transmitter with which it is paired, the CPU will know that the detected item is blocking the signal.

The system also has a calibration sequence that is performed after each object is measured while waiting for the next object. Specifically, when it receives a signal from its corresponding transmitter, and when it does not receive a signal from its corresponding transmitter, the output of each receiver is measured to determine its raw output. Based on the raw output of each receiver, a certain threshold for determining the presence of a signal is calculated and stored in the computer for use with the next object.

There are several problems with this arrangement. First, the necessity of paired transmitters and receivers creates an awkward structure in which either the transmitter or receiver must be positioned above the conveyor (thus taking up space and possibly blocking larger items) and below the conveyor (thus disadvantageously requiring a section break in the conveyor just at the measuring device). Also, the following facts limit the size of the package that can be measured: each transmitter is positioned on the opposite side of the measurement platform from the corresponding receiver. In addition, the system uses a great deal of computing power to recalibrate each signal receiver after each object is measured.

U.S. patent No.5,878,379 ("Dlugos") discloses a size weighing apparatus, entitled "Coarse Volume Measurement with interlock". The device comprises a balance for weighing the package, together with a measuring frame having three axes. Pairs of signal transmitters and receivers are along each axis. The signal emitter and receiver are positioned close to each other and oriented such that if one side of the package is positioned near the pair, the signal from the emitter will be reflected by the package and propagate to the receiver.

One of the basic problems with the Dlugos device is that: it provides only a rough measure of the size of the package. Based on the switching (polling) of these individual sensor pairs, the device can only achieve a limited accuracy. These measurements are so coarse that the apparatus comprises a device for indicating to the user that he needs more accurate measurements, which need to be performed manually by the user.

Disclosure of Invention

Accordingly, there is a need for a dimensional measurement device that solves or mitigates one or more of the above-mentioned problems. The sizing device should measure at least one dimension, although it is most preferred to measure three dimensions. Preferably, the dimensional measuring device will provide accurate measurements, be convenient and effective to use, practical and flexible.

Thus, according to the present invention, there is provided an apparatus for measuring at least one dimension of a package, the apparatus comprising:

a size measuring device extending along a measuring axis and sized and shaped to receive the package in a measuring position; and a central processor configured to communicate with the dimensional measurement device, receive dimensional information, and determine the dimensions;

the dimensional measurement device includes a plurality of receiver modules removably connected to one another;

each receiver module comprises a plurality of signal receivers spaced along the measurement axis;

a plurality of receiver modules connected in series, wherein each receiver module is configured such that all of the plurality of receiver modules are in communication with the central processor, thereby facilitating the central processor to receive the size information;

each receiver includes a local controller connected thereto.

According to another aspect of the present invention, there is provided a method of calibrating a plurality of signal receivers, the method comprising:

for each of the receivers, the receiver is,

(i) exposing the receiver to a maximum signal;

(ii) measuring a receiver output from the maximum signal;

(iii) exposing the receiver to a minimum signal;

(iv) measuring a receiver output from the minimum signal;

(v) determining a mapping function that maps an output from the maximum signal to a predetermined reference maximum value and maps an output from the minimum signal to a reference minimum value;

(vi) storing the mapping function for use in a plurality of measurements.

According to another aspect of the present invention, there is provided a receiver module comprising:

a plurality of signal receivers arranged generally in a row, and a substrate carrying the plurality of signal receivers;

a detachable connection means for connecting the receiver module in series to other receiver modules to form a dimensional measurement device with the signal receiver positioned along a measurement axis;

a local controller connected to the plurality of receivers.

According to another aspect of the invention, there is provided a method of determining the dimensions of an article, the method comprising the steps of:

placing an object in a measurement position associated with a dimensional measurement device comprising a row of signal receivers;

starting a signal source;

obtaining a set of measurements of the receiver output;

accessing a stored calibration set of receiver outputs, wherein each calibration set of receiver outputs is associated with a particular size;

selecting a calibration set of receiver outputs that is closest to the measurement set of receiver outputs;

determining a size of the object using a particular size associated with the closest calibration set of receiver outputs.

Determining a size of the article using the particular size associated with the closest calibration set of receiver outputs.

According to another aspect of the invention, there is provided a method of calibrating a dimensional measurement device, the device comprising an array of signal receivers, the method comprising:

selecting a set of N adjacent receivers;

positioning at least one calibration object at each of a plurality of locations within the active area of the N adjacent receivers, thereby simulating an object under test having an edge at each of the locations;

activating a signal source when a calibration object is placed at each position;

reading a calibration set of receiver outputs for each of the positions;

storing the output calibration set for use in object measurements.

Drawings

Reference is now made to the accompanying drawings, which illustrate preferred embodiments of the present invention, by way of example only, and in which:

FIG. 1 is a perspective view of a measuring device;

FIG. 2 is a schematic view of the apparatus;

FIGS. 3a and b are views of the top and bottom sides of a receiver module, respectively;

FIGS. 4a, b, c and d illustrate the connection and mounting of the receiver module;

FIG. 5 is a schematic diagram of an initial phase of a first calibration step;

FIG. 6 is a schematic diagram of a next stage of the first calibration step;

FIG. 7 is a schematic illustration of a subsequent stage of the first calibration step;

FIG. 8 is a schematic illustration of a second calibration step;

FIG. 9 is a schematic illustration of an alternative measurement method;

10a, b and c schematically show the actuation of the device by sequential scanning;

FIG. 11 is a schematic illustration of the exclusion of ambient signals during scanning;

FIG. 12 illustrates the effect of energy reflection by the lens; and

fig. 13 shows a segmented lens.

Detailed Description

Referring now to FIG. 1, an apparatus 10 is shown for measuring the length, width and height of an article. Preferably, the object comprises a package and the apparatus 10 is used to measure the dimensions of the package, to determine appropriate shipping costs, etc. The apparatus 10 shown in fig. 1 is a stationary apparatus for making volumetric measurements of packages (i.e., measuring their length, width and height). In other words, the apparatus 10 of FIG. 1 is used by a user to place a package on the measurement frame 12 of the apparatus 10. In the embodiment of fig. 1, the apparatus 10 does not operate with a conveyor belt.

In the preferred embodiment of fig. 1, the apparatus 10 is configured to measure three dimensions (length, width and height) of a package. It should be understood that the invention described herein may be used to measure one or more dimensions of an article.

The measuring frame 12 of the apparatus 10 includes a substantially upright back 14 and a platform 16. In this preferred embodiment, the package is measured by placing it in a measuring position, against back 14 and on platform 16.

It is believed that in many shipping applications, it is desirable to determine the weight of the package being shipped. Therefore, it is preferred that a weight measuring device (not shown) be positioned below the platform 16 so that the platform 16 acts as a platform for the weight measuring device. Thus, when a package is placed in the frame 12, its dimensions are measured and it is simultaneously weighed.

The apparatus 10 includes three dimensional measurement devices positioned along three measurement axes. The width dimension measuring device 18 is positioned along a width measurement axis 24. The length dimension measuring device 20 extends along a length measuring axis 26. The height dimension measuring device 22 extends along a height measurement axis 28. Preferably, the sizing devices 18, 20 and 22 have a substantially flat surface sized and shaped to receive the package adjacent thereto with the package 32 in the measuring position. Thus, as shown in FIG. 1, package 32 is received adjacent sizing devices 18, 20, and 22 in the measuring position.

Preferably, each dimension-measuring device 18, 20, 22 comprises a row of signal receivers 34, the receivers 34 extending along the associated measuring axis (24, 26 or 28). The dimensions of each dimension of the package 32 are determined by determining the characteristics of the signal received by each receiver 34, as will be described in detail below.

Preferably, each sizing device includes a plurality of receiver modules 36, which may be removably attached to each other. Preferably, each receiver module 36 includes a linear array of energy receivers 34. Preferably, receiver modules 36 are connected in series such that modules 36 form each of the dimension measuring devices with a row of receivers 34 along each dimension measuring device.

Preferably, each receiver module 36 is configured such that all receiver modules communicate with a central processor 38 (see FIG. 2) of the apparatus 10, thereby facilitating the central processor 38 to receive dimensional information from the receiver modules 36. Central processor 38 is preferably configured to communicate with each of sizing devices 18, 20, 22, to receive sizing information from sizing devices 24, 26, and 28, and to determine each of the dimensions (length, width, and height). In one embodiment, devices 24, 26, and 28 are communicatively coupled to processor 38 via hub 37. A hub cable 39 connects the devices 24, 26, and 28 to the hub 37, and a processor cable 41 connects the hub 37 to the processor 38. It should be understood, however, that other forms of connection between the devices 24, 26 and 28 and the processor 38 are possible, and the form of connection used will depend on a number of factors, including physical and size limitations.

Each of the dimension measuring devices 18, 20 and 22 is shown in fig. 1 and 2 as having three modules 36. It should be understood by those skilled in the art that the dimensional measurement device need not have this particular number of modules 36, as will be appreciated with respect to the present invention. Rather, as described in detail below, the number of modules 36 may vary and may be adapted by a user of the device 10 to the particular environment in which the device 10 is used. Thus, each device 18, 20, 22 may preferably have as few as one module 36, and may have any number of modules 36. Although less preferred, the present invention contemplates that the sizing devices 18, 20, 22 may not include the module 36 described herein.

Fig. 2 is a schematic illustration of the sizing devices 18, 20, 22 and their connections to the central processor 38. As shown in fig. 2, modules 36, each including a receiver 34, are connected in series. Preferably, each receiver module is configured such that all receiver modules 36 in each sizing device communicate with central processor 38, thereby facilitating receipt of the sizing information by central processor 38. Depending on the location of a particular module 36, that module 36 may communicate with the central processor through other modules 36 located between it and the central processor 38. Likewise, each module 36 is preferably configured to allow other modules 36 located further away from the central processor 38 to communicate with the central processor 38 via the module 36. In summary, each module is configured to: communicate with central processor 38 via other modules 36 if desired, and allow other modules 36 to communicate with central processor 38 via it if desired.

The receiver module 36 is schematically shown in fig. 3a and 3 b. Fig. 3a shows the top side of each receiver module, while fig. 3b shows the bottom side. Each module 36 preferably includes a microcontroller 40. In a preferred form of the invention, microcontroller 40 operates as a local controller for each module 36, controlling a number of functions, including the communication functions of module 36.

It should be appreciated that preferably, each module 36 includes a connector 42 at each end for connecting to an adjacent module 36. A communication path extends between each connector 42 and microcontroller 40 through which signals propagate from adjacent modules 36 through a particular module 36. Thus, information from adjacent modules 36 will travel through connector 42, to microcontroller 40, on through another communication path, and to other adjacent modules 36 through other connectors 42. The microcontroller 40 also preferably receives power through a connector 42 to power the operation of the microcontroller 40.

A microcontroller 40 is operatively connected to each receiver 34 so that the output from each receiver 34 can be read by the microcontroller 40. It should be understood that in accordance with the present invention, the dimensions of the packages 32 (or other objects) are determined in response to the output of the signals they receive, with reference to the receivers 34. In a preferred embodiment, receiver 34 includes a phototransistor that is responsive to light.

Also, in the preferred embodiment, the modules 36 each include a unified energy source 46 located thereon. As shown in FIG. 1, a combined energy source 46 is positioned along the sizing devices 18, 20, 22 to form a combined energy source 48 for each device 18, 20, 22. Typically, the package 32 is sized by activating the combined energy source 46 and reading the output of the receiver 34. When the package 32 is received against the surface 30, light from the associated energy source 46 will be reflected by the package and received by the receiver 34. However, where the package 32 does not arrive, there will be no reflection of energy by the package 32, and the output of such a receiver 34 will reflect the fact that energy from the associated energy source 46 is not reflected by the package onto the receiver 34.

Preferably, the combined energy source comprises rows of LEDs 50, wherein each LED50 is positioned immediately adjacent to an adjacent LED 50. The purpose of this close proximity is to allow the joint energy source 46 to emit a substantially uniform light signal, rather than a boosted signal with a peak at each LED50, and a lower value (valley) between LEDs 50. Fig. 3a shows an example of a combined energy source 46 with closely adjacent LEDs 50. A substantially uniform light output 52 is shown. As shown, the output 52 is substantially uniform upon incidence into the package 32, with substantially no peaks and lower values.

It will be appreciated that having a joint energy source 48 (as opposed to a source that fluctuates according to location) is preferred because with a uniform source having a substantially uniform output 52, the following risks are greatly reduced: when the energy source 48 is activated, the particular receiver 36 will be located at a dark spot. This situation may lead to an erroneous dimensioning of the relevant dimension, since when in fact the package extends to a particular receptacle 36, it appears that the package does not extend to that particular receptacle 36.

It is contemplated that the relationship between the number of discrete energy sources (e.g., LEDs 50) forming the combined energy source and the number of receivers 34 may vary. For example, there need not be a receiver 34 for each LED50, and in fact, in a preferred embodiment, the number of receivers 34 is substantially less than LEDs 50. Preferably, the number of discrete energy sources forming the combined energy source is determined by the number and configuration required to provide uniform energy coverage 52 for all receivers in the receiver module (36).

Although the preferred embodiment of the present invention includes a combined energy source 48 that includes rows of closely adjacent LEDs 50, it should be understood that other methods of measuring dimensions are possible. For example, the energy source may comprise a fluorescent source, or other type of energy source, such as ultrasound, radio frequency, radar, or suitable signal or energy type. As another example, the device 10 may not include a signal source at all, and the package size may be determined by: the difference in the ambient light incident on the different receivers 36 is measured. Alternatively, the signal source may not be mounted on the module 34, but rather remote from the module 34, so that when the package 32 is placed on the frame 12, the package will block light from the light source from reaching certain receivers 34, thus allowing the package 32 to be sized. Other possible variations include the use of signals other than light (e.g., ultrasonic signals). Other configurations are possible. Importantly, receiver 36 is positioned such that: the difference in the amount of energy reaching different receivers allows the apparatus 10 to determine the size of the package 32. The receiver 34 will need to be compatible with the received energy. Also, most preferably, the energy levels should be uniform (i.e., not flutter or fade).

Fig. 4a and 4b show how the modules 36 fit together. As shown, adjacent modules 36 are serially connected together by a bridge plate 44, the plate 44 being configured to receive the connectors 42 of two adjacent modules 36. As best shown in fig. 3b, the connector 42 is arranged such that: unless the module 36 is properly oriented, the module 36 cannot be inserted into the bridge plate 44. This prevents incorrect installation of the module 36.

Fig. 4c and 4d show a module holder 54, which holds the module 36. Preferably, the retainer 54 is formed by aluminum extrusion, but other compositions or forming methods are contemplated. Preferably, the retainers 54 each include two retaining slots 56 for receiving the edges of the modules 36 to support them in place. The module 36 is inserted towards the outside, i.e. the receiver 34 and the LED50 face towards the surface 30.

To protect the receiver 34 and the LED50, the device 18, 20, 22 also preferably includes a lens 58 that receives the package 32 near its outer surface, which is positioned for measurement. The lens 58 is carried in a lens retaining groove 60, the groove 60 being formed in the holder 54, the lens 58 serving to protect the energy source 46 and the receiver 34 while allowing the energy for measurement to pass through.

The lens 58 is configured to allow the signal sensed by the receiver 34 to pass therethrough. Thus, in a preferred embodiment, the lens 58 is light transmissive (most preferably, transparent, and colorless). Also, the lens 58 is preferably scratch resistant, so as to prevent scratches from interfering with signal transmission.

To install the modules 36, the modules 36 for each device (18, 20, 22) are connected in series using connectors 42 and boards 44. They are then inserted into the slots 56 from the edge of the retainer 54, with the retainer 54 positioned within the frame 12. Then, the lens 58 is inserted into the groove 60 from the end of the holder 54.

It should be understood that the lens 58 is typically not completely transparent. In other words, some of the infrared light from the LED50 will be reflected by the lens 58 and reach the module 36, rather than passing through the lens 58 and reaching the package 32. Thus, the receiver 34 will receive some energy from the source 34 that is not reflected by the package 32, but is reflected by the lens 58. The result is an "energy fog" (fog), or "infrared fog" 84, around the receiver 34. Fig. 12 shows how the fog 84 is generated and how the package 32 is visualized (apear) by the fog 84 to the receiver 34 and processor 38. As shown, when the fog 84 is present, the contrast between the package and its surroundings is substantially reduced, thus making it difficult for the processor 38 to discern the edges of the package 32.

Therefore, it is preferred that the device 10 include a segmented lens 58 for reducing or eliminating the fog 84 for improved accuracy. Segmented lens 58, including segments 58a and 58b, is shown in FIG. 13. The lens 58 is divided into two sections by an opaque divider 86, the divider 86 extending along the length of the lens 58 and being disposed above and between the receiver 34 and the source 48 when the lens 58 is installed. The divider 86 is positioned and sized such that energy emitted from the source 48 that would otherwise be reflected by the lens 58 and incident on the receiver 34 is incident on the non-reflective divider 86. The dividers are simultaneously sized and positioned such that: by passing through the opposite side of the divider 86, light from the source 48 may pass through the divider 86, enter the package 32, and reflect back to the receiver 34. Thus, the divider 86 reduces or blocks the fog 84 while allowing light reflected by the package 32 to pass through, thus allowing objects to be measured.

It is contemplated that other structures may be used to reduce or prevent the fog 84 by preventing energy that has been reflected by the lens 58 or will be reflected from the lens 58. Preferably, such energy is prevented from generating the mist 84, thereby improving the legibility of the edges of the package 32. It is believed, however, that the present invention includes the use of the apparatus 10 without reducing or impeding the fog 84, particularly because of the preferred calibration procedure described below.

It is believed that because of manufacturing tolerances, imperfect quality control, and other factors, different receivers may produce different outputs in response to the same input. For example, some receivers 34 may produce different non-zero outputs in response to a zero input signal. In other cases, the same non-zero input signal may produce different outputs in different receivers 34. It is therefore useful to calibrate each receiver 34 in the apparatus 10 in a first calibration step, thereby solving this problem. The purpose of the first calibration step is to ensure that the raw output from each receiver 34 is converted into information that can be correctly compared with the information received from the other receivers 34. Thus, in a first calibration step, each receiver 34 is exposed to the maximum signal and its output is measured. The receiver 34 is then exposed to the minimum signal (i.e., the minimum signal that the receiver should be able to receive during operation) and the minimum output is measured. A mapping function (mapping function) is then determined which maps the maximum output and the minimum output to a predetermined reference maximum and a predetermined reference minimum, respectively. These predetermined reference maximum and minimum values are constant for all receivers 34. Thus, once this first calibration step is completed, the raw size information (i.e., the output signal from receiver 34 in the preferred embodiment) is converted into adjusted size information that can be used for comparison with adjusted size information from other receivers 34. At this stage, if the two adjusted receiver outputs are equal, they are considered to have accepted the same signal lead-in.

For example, a preferred method for the first calibration step is shown in fig. 5, 6 and 7. As shown in FIG. 5, in a preferred embodiment, a 100% reflective calibration object 62 is placed over the receiver 34 and the source 48 is activated. In the example of fig. 5, the maximum raw signal output of four receivers 34 is shown. As shown in fig. 5, these maximum signal outputs are all different from each other. The maximum raw signal level for each receiver 34 is recorded and stored.

Then, as shown in fig. 6, an opaque calibration object 64 is placed over the receiver 34, which object 64 does not reflect the signal and does not allow the signal to pass in from its other side. This is the case for the minimum signal and, in theory, the output from each receiver 34 should be zero. However, the minimum raw signal output shown in fig. 6 is not equal to zero and is different from each other because of manufacturing tolerances, imperfect quality control, and the like. The minimum raw signal level for each receiver 34 is recorded and stored.

The mapping function for each of the four receivers 34 is shown in fig. 7. For each of the four receivers, the maximum signal output is mapped to a predetermined reference maximum, represented by the "100%" reference level shown in fig. 7. Similarly, each minimum signal output is mapped to a predetermined reference minimum, represented in fig. 7 by a "0%" reference minimum.

Most preferably, the maximum and minimum raw signal levels for each receiver 34, as well as the mapping function for each receiver 34, are stored in a local controller 40 of module 36, which includes the particular receiver 34. In this most preferred embodiment, module 36 may be used in any device 10 without having to repeat the first calibration step, because this calibration information maps the output of each receiver 34 to a predetermined reference maximum value that is standard for all modules 36. Thus, once the calibration steps for determining the mapping functions for each receiver 34 are completed and once these mapping functions are stored in the local controller 40, the module 36 can be used in any device 10 without having to repeat the first calibration step, and can be moved from one device 10 to another without having to repeat the first calibration step. This configuration provides significant flexibility to the apparatus 10. If more modules 36 are needed for the apparatus 10 because of the large packaging 32, they can be conveniently added. Similarly, used and/or defective modules 36 may be readily replaced.

It should be appreciated that other modes of storing calibration information from the first calibration step may be used in the present invention. For example, central processor 38 may store calibration information for each receiver 34. However, this configuration is less preferred because it limits the flexibility and replaceability of the module 36.

Preferably, the controller 40 is programmed to communicate with the processor 38 when installed, or when any module 36 is added or removed, and to number itself according to their position along the series of modules 36 in each device 18, 20, 22. Processor 38 then locates the information, allowing a determination to be made where each module 36 is located, and thus where each receiver 34 is located.

It should be appreciated that the modules 36 are preferably of standard construction (i.e., they are all preferably substantially identical in construction and function). This results in modules 36 being interchangeable, as described above. In addition, in this way, the processor 38 knows the location of each receiver 34 located on any installed module 36. The result is that the dimensions of the object can be accurately measured, as described in detail below.

Preferably, the module 36 is configured such that the distance between adjacent receptacles 34 on the module 36 is constant. Module 36 is also preferably configured such that: when the modules 36 are connected in series to form one of the devices 18, 20, 22 having a row of receivers 34, the distance between adjacent receivers 34 on the devices 18, 20, 22 is constant.

In a preferred form of the invention, the devices 18, 20, 22 are calibrated using a second calibration step. The second calibration step is preferably performed when the modules 36 are connected in series and to the processor 38. In a preferred method of the second calibration step, the information resulting from the second calibration step is stored in a memory of the processor 38, in another memory which is used in the apparatus 10 as a whole, or in a memory which is used for at least one of the means 18, 20, 22 or in the whole.

The second calibration step is schematically illustrated in fig. 8. In a second calibration step, a calibration set of N adjacent receivers is used to generate receiver response information. In theory, N may be any integer greater than zero, but when N is an integer greater than 1, the second calibration step is most effective to improve detection accuracy and accuracy. In the example of fig. 8, N is equal to 3.

It should be considered that prior to the second calibration step, the outputs from all receivers 34 are mapped to a predetermined reference that is constant for all receivers 34 (this is done in the first calibration step). Thus, any two adjusted receiver responses may be suitably compared. If the adjusted outputs of both receivers 34 are the same, then the two signal inputs received by both receivers 34 may be considered substantially the same. Similarly, if the conditioned output of receiver X is a proportion of the conditioned output of receiver Y, then it can be said that the signal received by receiver X is about the same proportion of the signal received by receiver Y, where receivers X and Y can be any two receivers of devices 18, 20, and 22.

In a second calibration step, as shown in fig. 8, calibration objects 80 are positioned at a plurality of calibration positions in the active area of N adjacent receivers (labeled 1, 2, 3 in fig. 8). For purposes of the description herein, the plurality of calibration positions will be referred to as M calibration positions, where M is an integer greater than 1. In fig. 8, four of the M positions are represented by letters A, B, C and D for illustration. The calibration object 80 thus simulates the package 32 with an edge 82 that is positioned at the M locations A, B, C, D, etc. when placed at the measurement location.

"effective area" refers to an area along the measurement axis near the N receivers where a small change in the position of the edge 82 of the object 80 will change the output of one or more of the N adjacent receivers. This effect is illustrated in the "receiver response" diagram of fig. 8. In position a, the receiver 1, which is mostly covered by the object 80, receives energy from the source 48 and shows a high output. Receivers 2 and 3, which receive little or no reflected energy at this location, have a low output. In position B, the response of receiver 1 remains approximately the same, but receivers 2 and 3 receive slightly more reflected energy from source 48, and their output is higher. In position C, the receiver 2 is now partially covered by the object 80 and its output is therefore still higher. The receiver 3 receives more reflected energy from the source 48 because the object edge is closer to it and its output is therefore higher. At position D, the receiver 2 is now substantially covered by the object 80 and its output is almost the same as that of the receiver 1. The receiver 3 is now closer to the edge 82, receiving more reflected energy from the source 48 and having a higher output.

It is considered most preferred that the first calibration step is performed before this second calibration step. However, although not most preferred, the present invention also includes the use of a receiver 34 that has not undergone a first calibration step.

Continuing with the second calibration step, the source 48 is activated to generate a calibration set of receiver outputs for each of the M positions. The calibration sets of receiver outputs for each of the N receivers at each of the plurality of locations (for a total of M calibration sets of receiver outputs) are read and stored, preferably in the processor 38. It should be appreciated that due to the first calibration step, the adjusted outputs of all receivers 34 may be compared. Thus, the second calibration step need only be performed on a single set of N adjacent receivers in the device 10. The result of the second calibration step may then be applied to all sets of N adjacent receivers 34 on the devices 18, 20, 22.

After the second calibration step is completed, a total of M calibration sets of receiver outputs are stored, where each calibration set represents one of M locations within the active area of a set of N receivers used in the second calibration step. Since the results of the second calibration step can be applied equally to any group of N adjacent receivers, each calibration set of receiver outputs also represents a corresponding one of M positions within the active area of any other group of N adjacent receivers.

The measurement of the package 32 is preferably performed as described below. Apparatus 10 is provided, apparatus 10 including devices 18, 20, and 22. The devices 18, 20 and 22 each include a plurality of modules 36 connected in series and mounted in the frame 12. The module 36 has been calibrated using the preferred first calibration step described above. The mapping function for each receiver 34, which normalizes the raw output of the receiver 34 to a comparable regulated output, is stored on the local controller 40 of the module 36 carrying the associated receiver.

Once the device 10 is assembled, a preferred second calibration step is performed. A representative set of N adjacent receivers is used for the second calibration step and the output calibration set is stored in the processor 38, or in other memory used in its entirety for the devices 18, 20, 22, or in memory used in its entirety for the apparatus 10. Because the receiver output is normalized in the first calibration step, the second calibration step need only be performed on one set of N adjacent receivers 34, and the results can be applied to all other sets of N adjacent receivers 34 on the device 10.

The package 32 is placed on the frame 12 at the measurement location. The source 48 on each device 18, 20, 22 is activated and the output of each receiver 34 (i.e., the raw size information) is read and adjusted by the local controller 40 through the mapping function stored therein for each receiver 34. The adjusted receiver output (i.e., adjusted size information) is sent to processor 38.

The processor 38 stores or accesses the stored receiver response information from the second calibration step, including a calibration set of receiver outputs for the set of N adjacent receivers 34 at each calibration position (see, e.g., position A, B, C, D in fig. 8). This gives a total of M calibration sets of receiver outputs. Processor 38 reads the adjusted receiver output from module 36, thus producing a measurement set of receiver outputs (i.e., a set of receiver outputs, acquired for measurement). For a contiguous set of N adjacent receivers, processor 38 observes (i.e., looks at) a set of measurements of the receiver outputs. The processor 38 attempts to match the measured set of receiver outputs from the set of N adjacent receivers to a calibrated set of receiver outputs. If it cannot match, it moves to the next consecutive group of N adjacent receivers. If, in a particular group of N receivers, the output measurement set appears to match one of the calibration sets output by the receivers (i.e., the output measurement set indicates the presence of a wrap-around edge), then the closest calibration set output is identified. Each output calibration set is associated with a particular edge location within an arbitrary set of N adjacent receivers. Using this position, and using its knowledge of which set of N receivers is being observed, processor 38 determines the size of package 32.

A simplified illustrative example may use a device (18, 20 or 22) having six receivers, where N equals 3. Thus, in this example, there are two consecutive sets of N adjacent receptors 34. When making measurements, processor 38 looks at the measurement set of receiver outputs for the first set of N (i.e., 3) receivers and looks to match the measurement set to the calibration set of receiver outputs. If a match is found, the processor 38 determines the position of the package edge using its knowledge of which position within the N receivers each calibration set of receiver outputs corresponds to. If no match is found, the processor 38 moves to the next set of N receivers (receivers 4, 5, 6) and attempts to match the measured set of receiver outputs to one of the calibrated sets of receiver outputs. The same matching attempt is made. Note that as described above, the same calibration set of receiver outputs is used for each set of N adjacent receivers, since the receiver outputs are normalized in the first calibration step. Instead, the set of measurements of the receiver output will be different for each set of N receivers, depending on where the edge of the package is located.

It is believed that the magnitude of the output in any measured set of receiver outputs will be affected by factors unrelated to the edge location of the package 32. For example, a highly reflective package 32 will cause a receiver near the package 32 to output a higher level of light than a less reflective package 32. Preferably, therefore, processor 38 is programmed to identify edge patterns within the measured set of receiver outputs, even though the particular magnitude of the receiver outputs may vary for different packages 32.

Also, it should be appreciated that in some instances, features of a particular package 32 may have the contour of an edge, even where such an edge is absent. For example, a black package with a white label can create such a phantom edge profile. Thus, prior to establishing dimensional measurements of package 32, processor 38 is preferably programmed with an algorithm to identify ghost edges and filter them out.

It will be appreciated that the accuracy with which the processor 38 determines the dimensions depends on the number of calibration positions used in the second calibration step. If there is one calibration position every 1 mm, for example, then when a calibration set of receiver outputs is selected during the measurement, the measurement can theoretically be accurate to within 0.5 mm, but it is believed that other factors can affect accuracy. Therefore, if the distance between the calibration positions is larger, the measurement accuracy is lower. If smaller, the accuracy will be higher.

Again, the value of N is selected based on the required accuracy and based on the spacing of the receivers 34. Generally, a larger N will result in a more accurate measurement given a particular spacing of receivers 34. However, a larger N may also require more computational power and more memory for calibration data during the measurement process. Thus, N may be selected to optimize this tradeoff in any particular measurement environment.

Fig. 9 shows an alternative method of measuring the dimensions of the package 32. In the preferred measurement method described above, the processor looks at a measurement set of outputs for successive (i.e. non-overlapping) groups of N receivers. However, it may also be overlapping for consecutive groups of N receivers, as shown in fig. 9. In the example of fig. 9, N is 3, but each successive group of N receivers is offset from the previous group by only one, so that each group overlaps two receivers. The main result of this measurement method is that a set of N receivers can provide more matching between the measured set of receiver outputs and the calibrated set of receiver outputs, as shown in fig. 9. Thus, multiple measurements may be made for the same size. The measurements are then averaged to determine a final measurement. This method has the advantage of higher accuracy because, due to unforeseen circumstances, a single measurement is more likely to be subject to large errors than an average of multiple measurements.

The processor 38 may be contained within the frame 12. Alternatively, the processor 38 may be separate, such as part of a different computer connected to the frame. Preferably, the apparatus 10 includes a processor 10 to operate the apparatus 10, including calibration, dimensional measurement, and transportation cost calculations.

Similarly, it is preferred that the apparatus 10 includes a display device for displaying size and transportation cost information. This display device may be integral with the frame 12 or comprise a separate computer screen. Other display configurations are also contemplated by the present invention.

As mentioned above, the source 48 preferably includes rows of LEDs 50 that are immediately adjacent to one another. For measurement and calibration, the source 48 is activated, as is the receiver 34. The receptor 34 and source 48 are preferably activated by sequential scanning (i.e., activation of the receptor and LED is continuous, not all at once). The LEDs 50 may be gradually activated and deactivated in multi-cell increments (e.g., 5 at a time), as may the receiver 34. Alternatively, they may be activated or de-activated one at a time. Preferably, when a particular receiver 34 is activated, there is a sufficient amount of signal to ensure that the receiver 34 receives all of the signals it should receive. Sequential scanning is shown in fig. 10a-10 c.

It is also contemplated that other methods of activating the receivers 34, such as turning them all on at once, are also encompassed by the present invention.

Sequential scanning provides two main advantages. First, it saves electrical energy. Since the output from each receiver 34 is read, it is not necessary to have all other receivers turned on, nor to turn on the portion of the source 48 that is remote from the receiver 34 being read. Thus, the sequential scanning reduces the amount of energy used during the package measurement.

Second, in the preferred embodiment, controller 40 controls the reading of source 46 and receiver 34 (although it is contemplated that the present invention contemplates processor 38 controlling these functions). In the preferred embodiment, each receiver 34 is activated during the measurement process and is read immediately before the source 48 in the vicinity of the receiver 34 is activated. The purpose of the early activation of the receivers 34 is to allow reading to occur, corresponding to the influence of ambient light on each receiver 34. Then, when the source 48 is activated in the vicinity of the receiver 34, it is again read and the effect of the ambient light is subtracted to provide an accurate measurement that measures the effect of the source 48 on the receiver and excludes the ambient light. This scanning process is illustrated in fig. 11.

It should be appreciated that other methods may be used to exclude ambient light. For example, the signal from source 48 may be modulated to a particular frequency (i.e., 300kHz), and receiver 34 may be configured to detect only the modulated signal. Other forms of modulation may also be used. However, modulation is currently less preferred because of cost and physical board size considerations.

Preferably, the processor is configured to output the measurement data in a plurality of different formats. This includes printer-compatible formats, serial data (USB), formats configured for remote and local display, and various network formats (e.g., ethernet). It should be appreciated that compatibility with its many output formats allows the device 10 to be flexibly used in a variety of environments and situations.

While embodiments of the invention have been described in detail for a complete disclosure of the invention, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims. Some of these variations are described above, and others will be apparent to those skilled in the art. For example, the signal source may take a different form (e.g., ultrasonic) or may be modulated. Also, although not most preferred, the first calibration step may not be performed for the measurement method, which is included in the present invention. The present invention also contemplates that the devices 18, 20, 22 do not include the module 36. Also, although not preferred, the present invention contemplates that only one dimension of the package 32 or other object be measured.

Claims (30)

1. An apparatus for measuring at least one dimension of a package, the apparatus comprising:

a size measuring device extending along a measuring axis and sized and shaped to receive the package in a measuring position; and a central processor configured to communicate with the dimensional measurement device, receive dimensional information, and determine the dimensions;

the dimensional measurement device includes a plurality of receiver modules removably connected to one another;

each receiver module comprises a plurality of signal receivers spaced along the measurement axis;

a plurality of receiver modules connected in series, wherein each receiver module is configured such that all of the plurality of receiver modules are in communication with the central processor, thereby facilitating the central processor to receive the size information;

each receiver module includes a local controller containing calibration information for the plurality of signal receivers.

2. The apparatus of claim 1, wherein each receiver module is configured to communicate with the central processor via one or more other receiver modules.

3. The apparatus of claim 2, wherein each receiver module is configured to allow communication between at least one other receiver module and the central processor.

4. The apparatus of claim 1, wherein calibration information comprises a mapping function that maps a maximum response of each of the plurality of signal receivers to a predetermined reference maximum value and maps a minimum response of each of the plurality of receivers to a predetermined reference minimum value.

5. The device of claim 4, wherein the reference maximum and reference minimum are constant between receiver modules.

6. The apparatus of claim 1 or 5, wherein local controller is configured to receive raw size information from the plurality of signal receivers, apply the calibration information to the raw size information to produce adjusted size information, and transmit the adjusted size information to the central processor.

7. The apparatus of claim 1, wherein each receiver module is configured such that a spacing between adjacent receivers on each receiver module is constant.

8. The apparatus of claim 1 or 7, wherein each receiver module is configured such that a spacing between adjacent signal receivers on the dimensional measurement device is constant.

9. The apparatus of claim 1, wherein the local controller is configured to receive calibration data prior to the receiver module being connected to the dimensional measurement device, store the calibration data, and apply the calibration data to a package measurement made with the dimensional measurement device.

10. The device of claim 1, wherein each receiver module further comprises a signal source.

11. The apparatus of claim 10, wherein the signal source comprises a uniform signal source.

12. The apparatus of claim 11, wherein the uniform signal source comprises a plurality of signal points that are closely adjacent to one another, thereby producing a substantially uniform signal over a length of the receiver module.

13. A method of calibrating a plurality of signal receivers carried on a receiver module configured to be serially connected to other receiver modules to form a dimensional measurement device, wherein the signal receivers are positioned along a measurement axis, the method comprising the steps of:

for each of the receivers, the receiver is,

(a) exposing the receiver to a maximum signal;

(b) measuring a receiver output from the maximum signal;

(c) exposing the receiver to a minimum signal;

(d) measuring a receiver output from the minimum signal;

(e) determining a mapping function that maps an output from the maximum signal to a predetermined reference maximum value and maps an output from the minimum signal to a predetermined reference minimum value;

(f) the mapping function is stored on a local controller connected to the receiver module for use in multiple measurements.

14. The method of claim 13, wherein the storing step comprises storing the mapping function in a central processor of the dimensional measurement device.

15. A receiver module, comprising:

a plurality of signal receivers positioned substantially in a row; and a substrate carrying the plurality of signal receivers;

a detachable connection means for serially connecting the receiver module to other receiver modules to form a dimensional measurement device with the signal receiver positioned along a measurement axis;

a local controller coupled to the plurality of receivers, wherein the local controller is configured to store calibration information for the plurality of signal receivers prior to use.

16. The receiver module of claim 15, wherein the receiver module is configured to communicate with the central processor through at least one other receiver module.

17. The receiver module of claim 15, wherein receiver module is configured to allow at least one other receiver module to communicate with a central processor through the receiver module.

18. The receiver module of claim 15, wherein a spacing between adjacent signal receivers is constant.

19. The receiver module of claim 18, wherein the signal receiver is positioned such that: when a receiver module is connected in series with other receiver modules to form a dimensional measurement device, the spacing between adjacent signal receivers of the dimensional measurement device is constant.

20. The receiver module of claim 15, wherein the module is configured to be calibrated prior to use and to replace other receiver modules within a dimensional measurement device without requiring repetition of the calibration prior to use.

21. A method of measuring a dimension of an object, the method comprising the steps of:

placing an object in a measurement position associated with a dimensional measurement device comprising a row of signal receivers;

starting a signal source;

obtaining a set of measurements of the receiver output;

accessing a stored calibration set of receiver outputs, wherein each calibration set of receiver outputs is associated with a particular size;

selecting a calibration set of receiver outputs that is closest to the measurement set of receiver outputs;

determining a size of an object using a particular size associated with the calibration set of closest receiver outputs.

22. The method of claim 21, wherein the step of accessing comprises the step of accessing a stored calibration set of receiver outputs obtained according to the method of:

selecting a set of N adjacent receivers;

positioning at least one calibration object at each of a plurality of locations within the active area of the set of N adjacent receivers, thereby simulating a measured object having an edge at each of the locations;

activating a signal source when a calibration object is placed at each position;

a calibration set of receiver outputs for each of the positions is read.

23. The method of claim 22, wherein the step of selecting the calibration set of receiver outputs that is closest to the measurement set of receiver outputs comprises the steps of: (i) for each set of N contiguous receivers, attempting to match the measured set of receiver responses to a calibration set of receiver responses associated with the N contiguous receivers of the set, and (ii) finding the closest calibration set of receiver responses, and identifying the set of N contiguous receivers with which the closest calibration set of receiver responses is associated.

24. The method of claim 21, wherein N comprises an integer greater than 1.

25. The method of claim 23, wherein consecutive groups of N contiguous receivers are non-overlapping.

26. The method of claim 23, wherein consecutive groups of N adjacent receivers are overlapping.

27. A method of calibrating a dimensional measurement device that includes a bank of signal receivers, the method comprising:

selecting a set of N adjacent receivers;

positioning at least one calibration object at each of a plurality of locations within the active area of the N adjacent receivers, thereby simulating an object under test having an edge at each of the locations;

activating a signal source when a calibration object is placed at each position;

reading a calibration set of receiver outputs for each of the positions;

storing the calibration set of receiver outputs for matching the measurement set of receiver outputs to the calibration set during object measurement.

28. The method of claim 27, wherein N equals 3.

29. The method of claim 27, wherein the step of storing comprises the step of storing the outputted calibration set in a memory of a central processing unit.

30. The method of claim 27, wherein the reading step comprises reading a calibration set of receiver outputs, wherein the receiver outputs are adjusted such that the outputs are normalized for all receivers.