Abstract:
Automatic parcel sizing device ( 10 ) comprising: a trihedral parcel support ( 12 ) having three panels ( 12 A,  12 B,  12 C) for receiving a parcel ( 18 ) to be sized, each panel of which being disposed orthogonal to the other two panels and defining a vertex ( 20 ) at an intersection point of said three panels, an optical sensor ( 14 ) for obtaining an image of the parcel, and a processor unit ( 16 ) in signal communication with said optical sensor for determining from said image of the parcel the respective dimensions of three parcel edges ( 18 A,  18 B,  18 C) which have a common vertex ( 18 D), wherein said vertex of the trihedral parcel support is disposed upside down such that, thanks to the gravity, the parcel is always correctly placed regarding the trihedral parcel support and said optical sensor is placed below and at a fixed distance from said vertex.

Description:
TECHNICAL FILED 
     The present invention relates to the field of logistics, shipping and franking systems, and more particularly to a parcel sizing device for the automatic determination of the three dimensions of a parcel, which dimensions are used to determine the shipping charge or the postage amount for the parcel. 
     PRIOR ART 
     For a long time, determining the amount of parcel postage for a shipment depends on several parameters: services related to the shipment (next day delivery, delivery confirmation, insurance, etc.), the delivery destination, the weight and the size of the parcel. The destination and services may be manually entered by the sender. The weight may either be entered manually (in the case of using an external balance with a franking system) or be sent automatically (when the balance is connected to the franking system). The dimensions of the parcel can be determined manually or automatically by the sender with a sizing device. 
     One known device is a ruler that measures length, width and height of a parcel and the operator reports these measurements manually on a packing slip or in a computer for further processing. However, such sizing method is not adapted when at least a minimum level of automation is required, for instance in a logistic center. 
     U.S. Pat. No. 5,841,541 describes a method and apparatus for measuring the three dimensions of a parcel. The parcel is placed in the corner of a field of measurement upon a flat surface and against two adjacent walls. At the base of each wall, and along the angle where the adjacent walls meet, is a calibrated reflective strip. The calibration marks on each of the reflective strips are of known size and spacing. Two mobile sensors are activated for reading the number of visible calibrated marks and transmitting this data to a processor which calculates the length, width, and height of the parcel by subtracting the observed visible calibration marks from the number of possible calibration marks. The three dimensions (length, width, height) and eventually the weight can then be displayed and/or transmitted to a parcel processing system. However, this device has several drawbacks: the first is the use of two mobile sensors that is too expensive and therefore not justified for a small volume of shipment; the second relates to the position of the parcel against the trihedral reference formed by the three reference surfaces, which forces the user to bypass the sensors which are in the opposite corner of this trihedral reference (workaround is not always easy especially when the parcel is heavy); and the third is the size of the reference surfaces which defines a maximum measurable size for the parcel, the size of an edge being not measurable if the reflective markers are all hidden. 
     SUMMARY OF THE INVENTION 
     The present invention aims to overcome these disadvantages of the prior art to determine automatically the size of a parcel regardless of its volume with a low-cost and ergonomic device. The invention achieves these goals with an automatic parcel sizing device comprising: a trihedral parcel support having three panels for receiving a parcel to be sized, each panel of which being disposed orthogonal to the other two panels and defining a vertex at an intersection point of said three panels, an optical sensor for obtaining an image of the parcel, and a processor unit in signal communication with said optical sensor for determining the respective dimensions of three parcel edges which have a common vertex from said image of the parcel, wherein said vertex of the trihedral parcel support is disposed upside down such that, thanks to the gravity, the parcel is always correctly placed regarding the trihedral parcel support and said optical sensor is placed below and at a fixed distance from said vertex. 
     In an embodiment, the parcel support is made of a transparent material leaving the edges of the parcel appear to be sized. 
     In another embodiment, said three panels being joined together and each junction edge and said vertex are partially cut, thereby defining three apertures and a bottom hole through which reveal edges of the parcel and its vertex. Advantageously, said bottom hole has a shape of an equilateral triangle, each side of which has a length comprised between 20 mm to 60 mm. 
     In still another embodiment, said three panels are not joined but separated by a respective slot through which reveal edges of the parcel and its vertex. 
     For determining said respective dimensions of the three parcel edges, the processor unit can count a number of pixels representing each of said three edges of the parcel or determine the position of a pixel representing the corner of each of said three edges of the parcel. 
     Advantageously, said three panels are rectangle isosceles triangles such that said trihedral parcel support presents an inverse pyramid form with said vertex in the bottom. Preferably, each junction edge separating a panel from another has a length comprised between 100 mm and 600 mm. 
     Preferably, the optical sensor used to acquire the dimensions of the parcel is disposed at least at a distance of 50 mm from said vertex and is a CMOS or CCD camera which can be equipped with a wide angle lens. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood in view of the following detailed description, accompanied by illustrative and non-limiting examples with regard to the accompanying drawings, in which: 
         FIG. 1  is a schematic view illustrating an embodiment of the parcel sizing device according to the invention, 
         FIG. 2  is a schematic diagram of a processing unit suitable for use with the parcel sizing device of  FIG. 1 , 
         FIG. 3  is a view of another embodiment of the parcel sizing device according to the invention, 
         FIG. 3A  is a bottom view of the parcel support of the  FIG. 3  embodiment, 
         FIG. 4  is a view of still another embodiment of the parcel sizing device according to the invention, 
         FIG. 5  is a flowchart of process steps for calibrating the parcel sizing device according to the present invention, and 
         FIG. 6  is a flowchart of process steps for measuring a parcel via the parcel sizing device according to the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates one embodiment of the parcel sizing device according to the invention. 
     This device  10  comprises a trihedral parcel support  12 , an optical sensor  14  and a processing unit  16 . The processing unit  16  is connected to the optical sensor  14  to determine the three dimensions of a parcel  18  (illustrated as dotted line) placed on the trihedral parcel support  12 . 
     The trihedral parcel support  12 , on which is placed the parcel  18 , comprises three panels  12 A,  12 B and  12 C. The three panels are made of metal, plastic or other rigid material capable of withstanding the weight of a parcel without deformation. Each panel  12 A,  12 B,  12 C is placed perpendicular to the two others to form the corner  20  of a rectangular parallelepiped. However, panels  12 A,  12 B,  12 C could take the shape of rectangle isosceles triangles as shown in  FIG. 4  such that the trihedral parcel support presents an inverse pyramid form with the corner in the bottom. The junction edges  22 A,  22 B,  22 C separating a panel from another have lengths comprised approximately between 100 mm and 600 mm in order to provide a support large enough to hold a parcel but are not too bulky. The three panels  12 A,  12 B,  12 C are each supported by at least one foot  24 A,  24 B,  24 C, that may be perpendicularly to a base  26  of the parcel sizing device  10 . So, the trihedral parcel support  12  is located above the base  26 , the corner  20  forming the vertex of the trihedral parcel support being the nearest part of that base. 
     The optical sensor  14  (such as CMOS or CCD, typically a webcam with a resolution greater than 2 million pixels, for example) is fixed to the base  26  below and at a fixed distance from the vertex  20  of the trihedral parcel support  12 . The optical sensor  14  is located under the support, so that, the positioning of the parcel  18  in its support is not obstructed by the optical sensor as in the prior art. 
     The distance from the optical sensor  14  to the vertex  20  is approximately at least 50 mm in order to maintain a sufficient depth of field between the parcel  18  to size and the lens of the optical sensor  14 . The optical sensor  14  is preferably equipped with a wide angle lens to minimize the minimum distance required between the trihedral parcel support  12  and the optical sensor  14  to entirely acquire the three edges of the parcel to size. 
     The processing unit  16  includes appropriate software and hardware for the acquisition and the processing of images transmitted by the optical sensor  14  to determine the three dimensions of the parcel and for transmitting these dimensions to a shipping or franking system. 
     In one embodiment, the processing unit  16  is typically a microcomputer comprising a central processing unit  16 A, which may include one or more computer readable storage media  16 B. The microcomputer may interface with a human operator via an output, which may include a visual display  16 C to display text, graphics, video, and other visual data and a printer  16 D for printing these data if necessary. The computer may receive inputs via a keyboard  16 E, and/or any other suitable user interface (a mouse or a trackball for example). 
     In one other embodiment, the processing unit  16  can be incorporated in the base  26  of the parcel sizing device  10 , an HMI interface (not shown) comprising input means and display means being available on that base for directly displaying the dimensions of the parcel or the corresponding shipping charge or franking amount from necessary postal data, more particularly the weight of the parcel if the base  26  is disposed on a weighing platform  28 . 
       FIG. 2  shows a schematic diagram of the processing unit  16 . A central processing unit  30  may communicate with various other components via a main bus  32  and other suitable communication lines (not shown). Data may be stored in volatile memory such as RAM  34 , program storage  36  and/or data storage  38 . The program storage  36  and/or data storage  38  may include various types of computer-readable media, such as CD-ROMs or other type of optical disks, ROMs, RAMs, EPROMs, EEPROMs, magnetic or optical cards and drives, flash memory, or other types of machine-readable mediums suitable for storing programmable instructions. Computer-readable instructions may be stored in the program storage  36 . When executed by the computer, these instructions may cause the computer to implement specific methods as described herein, and may cause the computer to operate in accordance with those methods. In an embodiment, execution of the instructions stored in the program storage  36  may transform a general-purpose computer into a computer configured to perform one or more methods embodied by the instructions. A clock  40  may be used to synchronize operation of the other elements of processing unit  16 . A network driver  42  may manage connections between a network interface  44 , such as a TCP/IP or other suitable interface, to allow the computer to communicate with other computers, operators, or other entities. A keyboard driver  46  may communicate with the keyboard to receive input from an operator. A mouse driver  48  may manage communication with a mouse to coordinate reception of input signals. A display driver  50  may manage communications between the processing unit  16  and the monitor, such as to display appropriate output on the monitor. Similarly, a printer driver  52  may manage communications with the printer. A graphics processor  54  may generate and manage manipulation and display of graphical elements such as 2D images, 3D images and objects, and other visual elements. 
     Turning to  FIG. 1 , the three panels  12 A,  12 B,  12 C are made of a transparent material (for instance Plexiglas) such that the parcel edges to size  18 A,  18 B,  18 C are entirely visible through the panels and therefore are sizeable by the optical sensor  14 . Those three edges to size have a common vertex  18 D which coincide with the vertex  20  of the trihedral parcel support  12 . 
     On the contrary, in the embodiment of  FIG. 3 , the three panels  12 A,  12 B,  12 C are made of a non-transparent material, a metal for example, and consequently, the adjacent junction edges  22 A,  22 B,  22 C of the three panels and the vertex  20  of the trihedral parcel support are partially cut, thereby defining three openings, or apertures  60 A,  60 B,  60 C, and a bottom hole  62  which reveal the edges of the parcel  18 A,  18 B,  18 C to be measured and its vertex  18 D. 
     Advantageously, the support of the parcel is black so as to bring out the edges of the parcel which are generally in light color. 
     As illustrated on  FIG. 3A , the bottom hole  62  has a shape of an equilateral triangle and the length of each side can vary from about 20 mm to 60 mm. The apertures  60 A,  60 B,  60 C of the edges have substantially rectangular shape, the short side size of the cuts can vary between 10 mm and 30 mm and the long side size can vary between 60 mm and 500 mm. 
     In the embodiment of  FIG. 4 , the three panels  12 A,  12 B,  12 C, do not join, and a slot  64 A,  64 B,  64 C is left in place of edges which normally join the panels together. The space left in place of the vertex and of edges let fully appear three edges of the parcel  18 A,  18 B,  18 C and its vertex  18 D, regardless of their size and thus make them visible by the optical sensor  14 . 
     The working of the parcel sizing device  10  will be now described in connection with  FIGS. 5 and 6 . Before the parcel sizing, the implementation of the device requires a calibration at the commissioning of the device (for instance in the factory). 
       FIG. 5  depicts a flowchart of process steps for calibrating the device  10 . This calibration may be performed by acquiring in a step  100  the image of a parcel for which its dimensions are known (this parcel is preferably of big dimension for instance a 1 m edges cube, moreover, preferably the edges of the parcel are graduated, in order to have precise lookup table even for large parcel). In a further step  110 , the acquired image and the known dimensions of the parcel are transmitted to the processing unit  16  for analysis. In a step  120 , on the basis of the transmitted image, the processing unit  16  detects by known calculation methods the parcel edges  18 A,  18 B,  18 C to size. In a next step  130 , the processing unit  16  counts the number of pixels along each of the edges  18 A,  18 B,  18 C or alternatively captures their positions. In a further next step  140 , the processing unit  16  establishes a lookup table between the number of pixels counted along each of the edges or the position of those pixels and the actual dimensions in millimeter of the edges  18 A,  18 B,  18 C. The processing unit  16  produces a millimeter equivalent for each pixel counted along the edges of the parcel. When the lookup table is defined, the calibration is complete and the parcel sizing device  10  is operational. 
     Once the calibration phase completed, the parcel sizing can be done.  FIG. 6  depicts a flowchart of process steps for measuring a parcel  18  using the device  10 . In a first step  200  the parcel to size is placed on the trihedral parcel support  12  so that three adjacent faces two to two of the parcel are in contact with the three panels forming the support. Thanks to the gravity, the parcel is always correctly placed regarding the reference trihedral. Once the parcel positioned, in a step  210 , the image is captured by the optical sensor  14  and transmitted to the processing unit  16 . The processing unit  16 , in a further step  220 , processes the image to detect the parcel edges  18 A,  18 B,  18 C to size by known calculation methods. In a next step  230 , the processing unit  16  counts along edges the numbers of pixel which form them or alternatively determine the position of pixels representing the corner of each of said three edges of the parcel. In a last step  240 , the number of pixels counted for each edge or the position of the pixels representing the corners is converted into a physical length (for instance in millimeter) using the lookup table established during calibration. 
     If the support is disposed on the weighing platform  28 , in a facultative step  250 , the weight of the package is determined. 
     In addition to processes the image of the parcel to detect the edges to size and size them, the processing unit may embed a shipping application software which determines automatically the postage amount for a parcel shipping in function of the require service (next day, certified, etc.), the shipping destination, the parcel size information and the weight of the parcel. 
     Examples provided herein are merely illustrative and are not meant to be an exhaustive list of all possible embodiments, applications, or modifications of the invention. Thus, various modifications and variations of the described methods and systems of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the relevant arts or fields are intended to be within the scope of the appended claims.