EP2618948B1 - Postal sorting process re-using information regarding treatment between sorting runs - Google Patents

Description

Technical area

The invention relates to a postal sorting method in which mail items perform at least two sorting passes in a machine to be sorted into sorting outlets of the machine and user processing information is available in the machine at a time. first sorting pass in relation to at least one mail piece (cf. DE-U-202 18 212 ).

Prior art

The context of the invention is more particularly that of the sorting of bulk mail items from the same sender. For example, in a spinning situation where a group of homogeneous mail items from the same sender are entered in the postal sorting machine, the machine operator can be brought to previously frame the position of the block of mail. recipient address (called "user frame" in postal terminology) in images of these mail items through a graphical interface so as to force OCR address recognition processing to work on a predetermined pixel area in pictures of mail items. This assistance of the machine operator makes it possible, among other things, to reduce the rate of recognition failure.

The machine operator may also be required to enter other user processing information useful for the automatic processing of mail items, for example the spatial position in the image of the pixel area corresponding to the address block of the mailer. sender. The machine operator can also enter as user processing information, the fact that the mail items have a particular tracking rule to avoid a return to the sender, etc.

Information describing the physical structure of mail items, ie whether they are plastic envelope mail items, or open mail items or magazine type mail items, etc. ., can also be entered into the postal sorting machine by the machine operator to optimize the operation of data processing and mechanical processing.

This user processing information can also be previously stored in a machine file and thus retrieved automatically instead of being entered manually by the machine operator.

Other user processing information relating to physical characteristics of the mail items may still be produced by the machine peripherals during the sorting of mail items such as weight, thickness or other physical quantities. The frame encompassing the area of the destination address block may also be determined by the processing of the sorting machine itself after a reliability step, i.e. when this position information of the address block has become statistically reliable, the level of confidence in the result of OCR address recognition may be a measure of this reliability.

All this user processing information which is related to the processing of homogeneous mail items in that they originate in particular from the same sender and have a very similar graphical appearance can therefore be used for the configuration or adjustment of the machine to contribute to the processing. optimization of its operation in the different sorting passes.

Presentation of the invention

The invention is based on the observation that this user processing information is unused after the first sorting pass of the mail items because the batch groupings of mail items homogeneous, which exist in the first sorting pass, disappear after the first sorting pass.

The object of the invention is therefore to make this user processing information, introduced by a machine operator or already previously recorded in a machine or produced in the first sorting pass by the data processing of the machine, available in the sorting passes. subsequently to exploit them in association with the mail items concerned.

The invention therefore relates to a postal sorting method according to which mail items perform at least two sorting passes in a machine to be ordered in sorting outlets of the machine and user processing information is available in the machine when of a first sorting pass in relation to at least one mail item, characterized in that it comprises the steps of associating in memory these user processing information to a graphic signature of the representative mail item of an image of the mail article and to recover, during the second pass of sorting said mail item, said user processing information associated with it from a pairing of graphic signatures according to a certain criterion of resemblance.

The descriptor of these graphic signatures is preferably invariant to the rotation of the digital images of the mail items to allow indexing and search graphics signatures that are robust during successive sorting passes. This descriptor can be based on local and global characteristics of the pixel images of mail items in multi-level of gray or in binary format according to a multi-scale partitioning, for example luminance statistics. Such a descriptor is for example described in the patent document EP 1 519 796 . In this document, it is the image component of a unique virtual mail item identifier. The criterion of resemblance For example, a graphic between two graphic signatures may be a normalized correlation coefficient.

According to the invention, during the machine recycling of a set of mail items for a second sorting pass, graphical signatures associated with user processing information are filtered to dynamically create a dictionary of graphical signature classes and detects a pairing between a graphical class and a graphical signature of a mail item calculated during the second sorting pass to recover the user processing information associated with that mail item. This makes it possible to obtain a better compactness of the information in machine memory, a better efficiency of matching searches of graphic signatures and a reduction of data exchanges. In particular, at the time of unloading a sort output receptacle at the end of the first sorting pass or again at the time of recycling a sort output receptacle at the beginning of the second sorting pass, the graphic signatures generated for mail items stored in the receptacle and related to user processing information are grouped and classified according to this user processing information to dynamically create a dictionary of graphical signature classes whose context is located at the sort output output port. question. The method according to the invention also makes it possible to recover user processing information for mail items processed in the second sorting pass but which did not have user processing information in the first sorting pass. This is the case, for example, for two batches of similar mail items unstacked in the first sorting pass on two different machines, whereas only the mail items of a first of the two batches have been associated with user processing information. In the second sorting pass, the method according to the invention makes it possible to recover user processing information for the mail items forming part of the second batch of mail items.

Each graphic class of the dictionary is therefore representative of one or more similar graphic signatures. Thus, for each receptacle recycled at the entrance of a postal sorting machine in a subsequent sorting pass, it is possible to have a small context of graphic classes that can be extended or reduced so as to adapt to mail items only. present at the entrance of this machine. According to the invention, each graphical class has a descriptor which can be an average value of descriptors of several similar graphic signatures. The similarity threshold between a graphical signature and a graphical class for matching can be adjusted, if necessary, to allow recovery of user processing information for mail items from different senders which have a strong graphical similarity.

The principle of creating a dynamic dictionary of graphical classes consists in presenting to a current graphic class dictionary each new graphic signature of mail article linked to user processing information to be recovered in a subsequent sorting pass. When paired with a graphical class present in the dictionary, the descriptor of the graphical class in question is updated by consolidation with the descriptor of the new graphic signature (the update consists in calculating an average value of the descriptors) . If not, a new graphical class is created in the dictionary with the descriptor as the new graphic signature.

This type of dynamic grouping of graphic signatures avoids the management and exchange of large databases between postal sorting machines or postal sorting sites. These directories or dictionaries of graphic signature classes can be part of a database organized and segmented by sort output receptacle. Dynamic grouping of graphic signatures also provides a limited search context for matching graphical signatures.

The invention can be applied to a postal sorting architecture exploiting unique virtual identifiers of mail items according to the technology of the company "Solystic" called "V-Id®" described in the patent document EP 1 519 796 mentioned above. In this case, the user processing information is conveyed through the successive sorting passes in connection with these virtual mail article identifiers. Recovering this user processing information strengthens the robustness of indexing and searching memory for unique virtual mail item identifiers.

• Lesdites informations de traitement usager peuvent comprendre des informations de position spatiale du bloc d'adresse de destinataire. Comme indiqué plus haut, le recouvrement de ce type d'informations de traitement usager permet de renforcer la robustesse du traitement de reconnaissance par OCR des adresses de destinataire ou encore la robustesse du calcul des composantes d'un identificateur virtuel unique d'article de courrier.
• Lesdites informations de traitement usager peuvent comprendre des informations de position spatiale du bloc d'adresse d'expéditeur.
• Lesdites informations de traitement usager peuvent comprendre des informations indicatives d'une caractéristique physique commune à plusieurs articles de courrier. Le recouvrement de ces informations à travers les passes de tri successives peut contribuer par exemple à optimiser le remplissage des réceptacles de sortie de tri.

The process according to the invention may have the following particularities:

• The user processing information may include spatial position information of the recipient address block. As indicated above, the recovery of this type of user processing information makes it possible to reinforce the robustness of the OCR recognition processing of the recipient addresses or the robustness of the computation of the components of a unique virtual item identifier of mail .
• The user processing information may include spatial position information of the sender address block.
• Said user processing information may include information indicative of a physical characteristic common to several mail items. The recovery of this information through the successive sorting passes can contribute, for example, to optimizing the filling of the sorting outlet receptacles.

Brief description of the drawings

• La figure 1 illustre de façon très schématique une machine de tri postal avec des sorties de tri munies de réceptacles pour le stockage d'articles de courrier triés.
• La figure 2 illustre le déroulement du processus de tri lors d'une première passe de tri selon l'invention dans la machine de la figure 1.
• La figure 3 illustre le déroulement du processus de tri lors d'une seconde passe de tri selon l'invention dans la machine de la figure 1.

An exemplary implementation of the method according to the invention is described below in connection with the drawings.

• The figure 1 illustrates very schematically a postal sorting machine with sorting outlets provided with receptacles for storing sorted mail items.
• The figure 2 illustrates the course of the sorting process during a first sorting pass according to the invention in the machine of the figure 1 .
• The figure 3 illustrates the course of the sorting process during a second sorting pass according to the invention in the machine of the figure 1 .

Description of the embodiments

On the figure 1 , the postal sorting machine 1 comprises a sorting conveyor 2 provided with a plurality of sorting outlets of which only five S1 to S5 are shown. The sorting machine 1 also comprises a control / command system 3 (a data processing unit including a memory) capable of performing OCR address recognition processing to control the actuators of the sorting conveyor so as to direct each mail item to one of the sorting outlets that corresponds to the recognized recipient address on the mail item.

The reference 4 designates a receptacle or tray associated with a sorting outlet and in which are stored and accumulated mail items directed to this sorting outlet.

The postal sorting machine 1 may be part of a larger postal sorting equipment which may include several postal sorting machines located in different postal sorting sites. The control / command systems 3 of these postal sorting machines can be interconnected through a communication network 5 to enable exchange or transfer of data.

In the context of the invention, the mail items P can be sorted into several sorting passes so as to be ordered by destination address (for example for distribution by the factor), in particular in at least two sorting passes, either on the same postal sorting machine or on two or more different postal sorting machines during the successive sorting passes.

In general, the sorting on the destination of a mail item requires a first pass of this mail item machine in a sorting center called sorting center "departure", followed by a second machine passage of this article mail in a sorting center called "arrival" sorting center.

The invention therefore applies to a postal sorting according to which mail items P are presented in stack at the entrance of a postal sorting machine, are sorted according to a first sorting plane (first sorting pass) so as to be arranged in sorting output receptacles 4 of the sorting machine, and then sorted and stored items P in each sorting output receptacle 4 are recycled to the input of the sorting machine (or other sorting machine). to be sorted again according to a second sorting plane (second sorting pass) so as to be sorted again in sort output receptacles 4, and so on for the subsequent sorting passes until a suitable order is obtained to a distribution by the factor.

In the context of the invention, user processing information PF is entered into a machine, for example, before the first sorting pass of a batch of homogeneous (shoddy) mail items from the same sender. In the example, it will be considered that this user processing information PF is the spatial coordinates of the recipient address block in the images of the mailpieces P of the spinneret, but the invention can be applied to other types of mailpieces. user processing information, whether machine-entered by an operator or still generated by a data processing machine.

The figure 2 illustrates now an example of implementation of the postal sorting process according to the invention during a first sorting pass of mail items P. In step 20, user processing information PF is entered into a machine by the machine operator, for example using a man / machine interface including a display screen 6 (see FIG. figure 1 ) and a pointing member 7 on the display screen according to a technique called "clipping" which consists of defining a frame 8 around the recipient address block in a typical image 9 of a mail item of the runner.

In step 21, a first mail piece P of the line is popped and is moved in the sorting conveyor 2. The digital image of a face of this first piece of mail P is captured by a camera or the like. this is well known and is temporarily stored in memory of the system 3.

In step 22, if user processing information is associated with the mail article P, a graphic signature or image profile is then derived from the digital image of the mail article P. This graphic signature has a numerical descriptor calculated for example from the luminance values of the pixels of the image as indicated above. The registration of this Sig graphic signature is associated in memory with the applicable PF processing information for this mail item. The association in memory can be obtained conventionally by a logical address link between the registration of the graphic signature and the location where these PF information are recorded or by filling a field of the registration of the graphic signature with the user processing information. Note that the graphic signatures can be stored in a database as represented here by the database BD internal to the system 3 but which can also be distant from the postal sorting machine 1. On the figure 2 , the database BD is illustrated symbolically in the form of a table whose lines correspond to records of different graphic signatures indicated by Sig1, Sig2, etc .... Each graphic signature such as Sig1 is associated with information of user treatment, indicated by PF for Sig1 signature.

In step 23, the process continues with destination address OCR recognition processing which is applied more particularly in the image area of the mail item defined by this user processing information PF. Note that steps 22 and 23 could be reversed without departing from the scope of the invention.

It is assumed that at this stage of the sorting process, the recipient address is uniquely recognized by OCR recognition processing and in step 23 the mail item is thus directed through the sorting conveyor 2 to a sorting outlet, for example the output S1, corresponding to this address recognized to be stored in a corresponding sorting output receptacle 4. It is assumed that in the system 3, a logical identifier IdBac is assigned to each sort output receptacle 4 of the machine and therefore this identifier IdBac can be associated in memory at step 22 in the database BD to the recording. Sig1 signature calculated for the corresponding mail item.

Steps 21 to 23 are repeated for each subsequent mailpiece P. At the end of this process of processing in the first sorting pass, system 3 has in memory a set of graphic signatures which are respectively linked to user processing information PF and to sort output receptacle identifiers. In this sorting process, other user processing information may be entered manually or generated automatically in the first sorting pass for others. Note that the method according to the invention can also operate without sort output receptacle identifiers, the tray identifiers used here to limit the search space for the pairing of graphic signatures in the second sorting pass.

When a sort output receptacle full of mail items is to be evacuated from the sorting machine to be recycled for the second sorting pass of mail items, in step 24 a dictionary of classes of graphic signatures is dynamically created associated with this receptacle (or a segment of the database BD which can be seen as a directory or local dictionary) in which each graphic class Sig _Mean of the dictionary is representative of the graphic signatures associated with the mail items stored in the receptacle and which are generally part of the same line and whose images are graphically similar. As indicated above, the descriptor of each graphic class corresponds to a consolidated value calculated from the descriptors of the corresponding graphic signatures, for example corresponds to the average value of these descriptors.

The figure 3 now illustrates the sorting process for a second sorting pass of mail items P. It is assumed at this stage of the sorting process that mail items stored in a sort output receptacle 4 are recycled to the input of the same machine. In step 30, a mail item receptacle is brought to the input of the sorting machine and its identification number IdBac is recognized by the machine. A segment or the entire database BD is then loaded in memory of the sorting machine so that a small dictionary of graphical classes is made available in memory of the machine.

In step 31, a first article of mail P recycled in the second sorting pass is thus depilated and moved in the sorting conveyor 2 of the machine. An image of the face of this mail piece is then formed again and a current _current Sig graphic signature is again computed on the basis of this image. In step 31, the dictionary in the database BD is scanned to detect a pairing, on the basis of a graphical similarity criterion based for example on a normalized correlation coefficient, between one of the graphical classes Sig _Mean of the dictionary and the current Sig signature _current . In case of detection of a pairing in step 32, the user processing information PF associated with the graphical class identified in the dictionary is retrieved by association in memory and the process continues in step 33 by a new processing of OCR recognition of recipient address which is applied more particularly in the area of the image of the mail item which is defined by the user processing information PF.

This new treatment therefore benefits from the input of user processing information PF introduced in the first sorting pass. This recovery of user processing information in the second sorting pass contributes, for example, to reinforcing the robustness of address recognition on mail items.

In the absence of detection of a match in step 32, the postal sorting process continues in step 34 by a conventional OCR recognition process without any particular setting. Then the mail sorting process continues in step 35 by transferring the mail item to a sorting outlet and returns to step 30 for a new mail item.

Steps 31 to 35 are repeated for the subsequent mail items to be sorted in the second sorting pass on the sorting machine.

In this postal sorting process, it should be understood that in general, items sorted and stored in a receptacle of a sorting outlet from a machine are recycled to the input of another postal sorting machine. There can thus be a large number of sort output receptacles distributed over a large number of sorting machines in the second sorting pass. In this context, it is advantageous to return to the level of the machine memory of each system 3 for a second sorting pass a limited context of graphical classes so as to accelerate the search for matching. For this reason, a dynamic dictionary of graphic classes associated with each receptacle is built at the end of the first sorting pass or at the beginning of a second sorting pass.

The principle of recovering the user processing information between the sorting passes according to the invention also applies to the sorting passes subsequent to the second sorting pass.

Claims (11)

1. A postal sorting method in which mailpieces (P) are subjected to at least two sorting passes in a machine so as to be sequenced in sorting outlets (S1-S5) of the machine (1), and user processing information (PF) is available in the machine during a first sorting pass in relation to at least a certain mailpiece, said postal sorting method being characterized in that it includes a step consisting, in a memory, in associating said user processing information with a graphical signature of the mailpiece that is representative of an image of the mailpiece, and in recovering (32, 33), during the second machine sorting pass of said certain mailpiece, said user processing information that is associated with it on the basis of matching of graphical signatures using a certain resemblance criterion.
2. A method according to claim 1, wherein, while a set of mailpieces are being recirculated into the machine for a second sorting pass, graphical signatures associated respectively with user processing information are filtered for the purpose of dynamically creating a dictionary of graphical classes, and wherein matching is detected between a graphical class and a graphical signature of a mailpiece as computed during the second sorting pass for the purpose of recovering the user processing information associated with said mailpiece.
3. A method according to claim 2, wherein each graphical class has a descriptor that is a mean value of descriptors of a plurality of graphical signatures.
4. A method according to claim 1, wherein said user processing information comprises information about the spatial position of the recipient address block.
5. A method according to claim 1, wherein said user processing information comprises information about the spatial position of the sender address block.
6. A method according to claim 1, wherein said user processing information comprises information indicative of a physical characteristic that is common to a plurality of mailpieces.
7. A method according to claim 6, wherein said information indicates that a mailpiece has a plastics wrapper.
8. A method according to claim 6, wherein said information indicates that a mailpiece is of the open type or of the magazine type.
9. A method according to any preceding claim, wherein said user processing information is fed into the machine during the first sorting pass by a machine operator.
10. A method according to any preceding claim, wherein said user processing information is pre-recorded in a memory in the machine.
11. A method according to any preceding claim, wherein said user processing information is produced by data processing in the machine during the first sorting pass of the mailpieces.

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