Control of the production of bookbinding articles through image recognition from printing files

Abstract

 A solution is proposed for controlling a production of batches, each one of a corresponding bookbinding product, the bookbinding product including a group of bookbinding elements each one having a plurality of pages. For each batch, a corresponding control method (A1-A16) includes the steps of providing (A1-A2) printing information and processing information of the bookbinding product, the printing information including a digital image of each page of the bookbinding product, and the processing information including an indication of a composition of the bookbinding product in terms of the bookbinding elements and an indication of a composition of each bookbinding element in terms of the corresponding pages; in the solution according to an embodiment of the invention, the control method further includes determining (A7-A9) a representative digital image of each bookbinding element, the representative digital image of the bookbinding element being determined among the corresponding digital images according to the processing information, and recognizing (A10-A16) each one of a set of selected exemplars of the bookbinding elements by acquiring a current digital image of the selected exemplar and comparing the current digital image with at least part of the representative digital images.

Description

[0001] The solution according to one or more embodiments of the present invention relates to the bookbinding field. More specifically, this solution relates to the control of the production of bookbinding articles.

[0002] The production of bookbinding articles (for example, sewn books) is a very complex process, which is composed of a sequence of various processing phases (executed in corresponding processing stations). Particularly, the production process of sewn books involves the printing of flat sheets (for example, starting from files containing corresponding digital images), the folding of the flat sheets into signatures, the gathering of the signatures into groups corresponding to the books, the sewing of the groups of signatures into book blocks, and the application of covers to the book blocks.

[0003] A problem of the production processes known in the art is of verifying a correct processing of different semi-finished products that are obtained in the various processing phases (for example, in the case of sewn books, flat sheets, signatures, groups of signatures, book blocks and covers). Indeed, such semi-finished products are subject to several manual moving operations by operators of a bookbinding plant (for example, for transporting them to the processing stations and for loading them therein). However, these moving operations are for their nature subject to human errors (since the semi-finished products may be easily confused among them). The problem is exacerbated by the fact that the number of semi-finished products that are processed every day is very high (from some thousands up to some millions); moreover, the semi-finished products vary continuously among different production batches (from either a dimensional or graphical point of view), so that the operators may not perform a mnemonic discernment thereof.

[0004] A further requirement is of monitoring each job associated with the production process of a corresponding batch (for example, a start, an execution and an end of its processing phase); this allows having a real-time representation of the progress state of the various jobs. Such information may be used for scheduling the submission of the jobs (in order to optimise their execution), and for interfacing with other company management systems (for example, a purchases system, a logistic system, a sales system, and the like).

[0005] A known technique for controlling the production processes (for the verification of the correctness of the semi-finished products and/or for the monitoring of the jobs) is based on the automatic recognition of the semi-finished products. Such recognition technique may be of the barcode type or of the image type.

[0006] Particularly, the barcode recognition technique exploits specific codes (for example, barcodes), which are printed in scrap areas of the semi-finished products intended to be removed at the end of the corresponding production process. This allows both verifying the correctness of the semi-finished products (by comparing the barcode being read from each semi-finished product with an expected value thereof) and monitoring the jobs (by reading the barcode of a semi-finished product at the start or at the end of each production phase to identify the batch which it belongs to). Moreover, it is also possible to affix an identification sheet (rib) with a barcode of the corresponding batch onto each pallet of semi-finished products, in order to be able to identify the batch through the reading of such barcode. However, the printing of the barcodes involves a cost increase (for example, for the need of providing wider scrap areas and for the difficulty of positioning the devices being used for their reading in correspondence to the scrap areas). However, the barcode recognition technique is not of general applicability; indeed, in some situations it is not possible to print the barcodes on the semi-finished products (for example, when no scrap areas are provided or their size is to small). Moreover, the management of the barcodes is complicated by the fact that the semi-finished products of different origin use barcodes with different format and/or encoding, and by the fact that such formats and encoding generally differ from those used in the other company systems. Particularly, the printing and the affixing of the identification sheets on the pallets require additional manual operations, which increase the costs of the production process and the possibilities of errors.

[0007] In the image recognition technique, instead, during a learning phase being preliminary to every processing phase, a series of digital images is acquired from several series of sample semi-finished products, so as to define a series of semi-finished products being expected repeatedly during the processing phase. During the actual processing phase, a digital image of each semi-finished product under processing is compared with the digital image of the semi-finished product that is expected at the moment to verify its correctness. However, the several learning phases may slow down the production process, with a negative effect on its yield; moreover, any possible loading error of the sample semi-finished products alters the corresponding learning phase, thereby invalidating all the next correctness controls of the semi-finished products. In any case, the image recognition technique cannot be used to monitor the jobs (because of the impossibility of executing whatever preliminary learning phase).

[0008] In its general terms, the solution according to one or more embodiments of the present invention is based on the idea of exploiting the printing digital images for controlling the production process.

[0009] Particularly, one or more aspects of the solution according to specific embodiments of the invention are set out in the independent claims, with advantageous features of the same solution that are set out in the dependent claims, whose wording is herein incorporated verbatim by reference (with any advantageous feature provided with reference to a specific aspect of the solution according to an embodiment of the invention that applies mutatis mutandis to every other aspect thereof).

[0010] More specifically, an aspect of the solution according to an embodiment of the invention provides a control method for controlling a production of batches, each one of a corresponding bookbinding product (for example, a book); the bookbinding product includes a group of bookbinding elements (for example, signatures and covers) each one having a plurality of pages. For each batch, the control method includes providing printing information and processing information of the bookbinding product. The printing information includes a digital image of each page of the bookbinding product; the processing information includes an indication of a composition of the bookbinding product in terms of the bookbinding elements (for example, a group of signatures of the book), and an indication of a composition of each bookbinding element in terms of the corresponding pages (for example, the pages of each signature and their arrangement on a corresponding flat sheet). In the solution according to an embodiment of the invention, the control method further includes determining a representative digital image of each bookbinding element; the representative digital image of the bookbinding element is determined among the corresponding digital images according to the processing information (for example, by setting it equal to the digital image of a front page of the signatures). The method continues by recognizing each one of a set of selected exemplars of the bookbinding elements (for example, the signatures loaded in an initial position in each processing station thereof, and/or the signatures under processing in it); this result is achieved by acquiring a current digital image of the selected exemplar (for example, by means of a camera of each processing station at the end of its setting and/or periodically during its operation), and comparing the current digital image with at least part of the representative digital images (for example, for determining the setting of the processing station for the batch and any possible setting error, and/or for determining any possible processing error).

[0011] A further aspect of the solution according to an embodiment of the invention provides a software program, which includes code means for causing a control system of a bookbinding plant to perform the steps of the this method when the software program is executed on the control system; moreover, a further aspect of the solution according to an embodiment of the invention provides a computer program product, which includes a non-transitory computer readable medium embodying a computer program, the computer program including code means directly loadable into a working memory of a control system of a bookbinding plant thereby configuring the control system to perform the same method.

[0012] A different aspect of the solution according to an embodiment of the invention provides a control system for a bookbinding plant, which includes means for causing the control system to perform the steps of such method.

[0013] A further aspect of the solution according to an embodiment of the invention provides a bookbinding plant, which includes one or more of such control systems.

[0014] The solution according to one or more embodiments of the invention, as well as further features and the advantages thereof, will be best understood with reference to the following detailed description, given purely by way of a non-restrictive indication, to be read in conjunction with the accompanying drawings (wherein corresponding elements are denoted with equal or similar references and their explanation is not repeated for the sake of brevity). In this respect, it is expressly intended that the figures are not necessary drawn to scale (with some details that may be exaggerated and/or simplified) and that, unless otherwise indicated, they are merely used to conceptually illustrate the structures and procedures described herein. Particularly:

FIG.1 shows an illustrative representation of a bookbinding plant in which the solution according to an embodiment of the invention may be used,

FIG.2 shows a principle block diagram of a control system that may be used to implement the solution according to an embodiment of the invention,

FIG.3 shows an example of application of the solution according to an embodiment of the invention, and

FIG.4 shows a collaboration diagram representing the roles of the main software components that may be used to implement the solution according to an embodiment of the invention.

[0015] With reference in particular to the FIG.1, an illustrative representation is shown of a bookbinding plant 100 in which the solution according to an embodiment of the invention may be used. The bookbinding plant 100 is used for the production of batches of sewn books; each batch includes a predetermined number of exemplars (all equal one to another) of a corresponding book - in the following, each type of object and its exemplars will be indicated with the same name for exposition simplicity.

[0016] For this purpose, a printing station 105 (for example, comprising one or more digital printers) generates a series of bundles of flat sheets 110, each one comprising a plurality of exemplars (all equal one to another) of a different flat sheet of the book of each batch; each flat sheet 110 comprises a plurality of corresponding pages of the book on each side thereof. The printing station 105 also generates a bundle of covers 115, consisting of the same number of exemplars (all equal one to another) of a cover of the same book.

[0017] The bundles of flat sheets 110 are transported in succession (for example, through pallets not shown in the figure) to a folding station 120 (comprising one or more folding machines). For each bundle of flat sheets 110, the folding station 120 generates a bundle of signatures 125 consisting of the same number of exemplars (all equal one to another) of a signature of the book; each signature 125 is obtained by folding one or more times a corresponding flat sheet 110 among its pages. The bundles of signatures 125 are then transported (for example, through pallets not shown in the figure) to a gathering station 130 (comprising one or more gathering machines). The bundles of signatures 125 are loaded into different hoppers of each gathering machine, each one of them supplying its signatures 125 individually to a conveyor; the conveyor gathers the signatures 125 in succession from the different hoppers so as to obtain groups of signatures 135, each one consisting of a group of exemplars of different signatures that define the book.

[0018] The groups of signatures 135 are supplied in succession to a stacking station 140 (comprising one or more stacking machines). The stacking station 140 places multiple groups of signatures 135 on top of each other so as to obtain corresponding stacks of signatures 145.

[0019] An automatic feeder 150 distributes the stacks of signatures 145 to a sewing station 155 (formed by one or more sewing machines); each sewing machine sews each group of signatures through continuous threads, so as to obtain a bundle of book blocks 160, consisting of the same number of exemplars (all equal one to another) of a book block that defines the book.

[0020] The bundles of book blocks 160 are transported from the sewing station 155 and the bundles of covers 115 are transported from the printing station 105 (for example, through pallets not shown in the figure) to a finishing station 165 (formed by one or more perfect-binding machines and/or back-gluing machines, one or more three-knife trimmer machines, and one or more case-in machines). The finishing station 165 applies a cover 115 to each book block 160, so as to obtain a bundle of books 170, consisting of the same number of exemplars (all equal one to another) of the book.

[0021] Passing to the FIG.2, a principle block diagram is shown of a control system 200 that may be used to implement the solution according to an embodiment of the invention. The control system 200 is used to control the production of the books in the bookbinding plant described above.

[0022] For this purpose, the control system 200 includes one or more cameras 205. Each camera 205 (for example, of the CCD type) is used to acquire digital images of various semi-finished products that are obtained in the different production phases of the books; for example, a camera 205 is arranged at an input of the folding station (in order to acquire a digital image of each flat sheet to be processed in succession), a camera 205 is arranged at each hopper of the gathering station (in order to acquire a digital image of each signature to be processed in succession), a camera 205 is arranged at an input of the stacking station (in order to acquire a digital image of each block of signatures to be processed in succession), a camera 205 is arranged at an input of each sewing machine (in order to acquire a digital image of each signature to be processed in succession), and one or two cameras 205 are arranged at an input of each machine of the finishing station (in order to acquire a digital image of each book block and a digital image of each cover to be processed in succession).

[0023] The control system 200 may also comprise one or more palmtop computers 210 (also known as tablet PCs, palmtops, pocket computers or PDAs). Every palmtop computer 210 consists of a small processing system, which literally fits in a hand. Typically, the palmtop computer 210 is formed by a central unit, which houses the various electronic circuits controlling its operation - such as a microprocessor, a working memory, drives for input/output units, and a wireless network adapter (for example, of the Wi-Fi type). The palmtop computer 100 further comprises a mass memory (for example, of the flash type), a display (for example, of the touch-screen type), some control buttons, and a camera. The palmtop computer 210 is provided to an operator of the bookbinding plant, who may use its camera to acquire digital images of the various semi-finished products being present in the bookbinding plant (for example, when loaded on the pallets).

[0024] Moreover, the control system 200 comprises a central computer 215 (for example, a PC). Typically, the central computer 215 is formed by a central unit, which houses the various electronic circuits controlling its operation - such as one or more microprocessors, a working memory, drives for input/output units, and a wired network adapter (for example, of the Ethernet type). The central computer 215 further comprises a mass memory (for example, one ore more hard disks), a monitor, a keyboard, and a mouse. A router (or switch) 225 manages the communications among the cameras 205, the palmtop computers 210 and the central computer 215, and between the central computer 215 and the outside of the bookbinding plant (for example, with other company systems via local network and/or with the outside via Internet). For this purpose, the cameras 205, the palmtop computers 210 and the central computer 215 are connected to the router 225 through a communication system 230 (for example, of wired type for the cameras 205 and the central computer 215, and of wire-less type for the palmtop computers 210).

[0025] In the solution according to an embodiment of the invention, the control system 200 exploits information already available for the generation of the semi-finished products for controlling the production of the books as well. Particularly, an example of application of the solution according to an embodiment of the invention is shown in the FIG.3.

[0026] For example, printing information 305 is already available for printing the flat sheets; the printing information 305 comprises a digital image I_i for each page of the book (with the index i that varies from 1 to a total number of pages Tp of the book). The digital image I_i is defined by a matrix of values for corresponding pixels that represent different elementary portions of the page; each pixel value defines its colour (for example, three components each one of 8 bits for an intensity of the Red, Green and Blue colours).

[0027] Processing information 310 is further available for defining the composition of the book (in terms of its signatures) and the composition of each signature (in terms of its pages); for each signature S_j (with the index j that varies from 1 to a total number of signatures Ts of the book), the processing information 310 comprises an indication of the pages to print on each side of a corresponding flat sheet F_j, and an indication of the folds P_k to be executed on the flat sheet F_j in order to obtain the signature S_j (with the index k that varies from 1 to a total number of folds Tp). For example, a first signature S₁ is formed by 4 pages defined by the digital images I₁-I₄; the digital images I₂,I₃ and the digital images I₄,I₁ are printed on a front side and on a back side, respectively, of a first flat sheet F1_, which is then folded only once by means of a fold P₁ between the pages I₂,I₃ (and I₄,I₁).

[0028] In the solution according to an embodiment of the invention, the printing information 305 and the processing information 310 is used to generate control information 315 for controlling the production of the books; for each signature S_j, the control information 315 comprises an indication of a digital image I_i representative thereof, in the following indicated as representative image R_j (for example, a pointer to such digital image I_i in the printing information 305); the representative image R_j is chosen among the digital images I_i of the pages of the signature S_j so as to be visually inspectable - typically, by setting it equal to the digital image I_i of a front page of the signature S_j. For example, a first representative image R₁ of the signature S₁ will be equal to the digital image I₁ of its front page.

[0029] The representative images R_j of the signatures S_j may then be used as usual for controlling the production of the books (for example, by comparing a digital image being acquired from each signature during a specific processing phase with the representative image R_j of a signature S_j expected at the moment in order to verify its correctness). However, in the solution according to an embodiment of the invention such result is obtained without requiring any learning phase being preliminary to each processing phase (since the representative images R_j are extracted directly from the printing information 305). This avoids any slowing down of the production process, with a positive effect on its yield; moreover, the representative images R_j are for their nature correct (and therefore free from any loading error of the signatures that might alter the learning phase, thereby invalidating the next correctness controls).

[0030] The solution according to an embodiment of the invention also allows using the representative images R_j for monitoring the production of the books (since it does not require any preliminary learning phase). For example, it is possible to acquire a digital image of a signature at the start or at the end of a processing phase; such digital image is compared with the representative images R_j in order to identify the signatures at such processing phase. Moreover, it is also possible to acquire a digital image of a signature parked in a pallet; such digital image is compared with the representative images R_j in order to identify the corresponding signature and provide associated information. The above-described solution allows obtaining such result without using any barcode (thereby avoiding the corresponding cost increases and management complications); moreover, such solution is of general applicability, and it does not require any additional manual operation (for example, for printing the identification sheets to affix on the pallets), with consequent reduction of costs and errors.

[0031] A collaboration diagram representing the roles of the main software components that may be used to implement the solution according to an embodiment of the invention is shown in the FIG.4. These software components are denoted as a whole with the reference 400. The information (programs and data) is typically stored on the hard disk and loaded (at least partially) into the working memory of the central computer when the programs are running, together with an operating system and other application programs (not shown in the figure). The programs are initially installed onto the hard disk, for example, from an external storage support. Particularly, the figure describes both the static structure of the system (by means of the corresponding components) and its dynamic behaviour (by means of a series of exchanged messages, each one representing a corresponding action, denoted with sequence numbers preceded by the symbol "A").

[0032] In particular, a series of printing files 405 is loaded from an external source - for example, via Internet (action "Al.Load"). Each printing file 405 (for example, in PDF format with dedicated tags) defines a corresponding book through its printing information (which defines the digital images of the different pages, and provides additional specifications for their printing - such as pagination rules, colour palettes, printing resolution, and the like) and processing information (which specifies the signatures that compose the book and the pages that compose each signature). The printing files 405 are generally provided by customers of the bookbinding plant, which have commissioned the production of the corresponding books thereto. A revision module 410 revises the printing files 405 so as to generate corresponding execution files 415 (action "A2.Revise"). Each execution file 415 defines the printing of the two sides of each flat sheet of the book, in a format recognized by the specific printers being used.

[0033] Moreover, a scheduler 420 controls the execution of a series of jobs (each one of them defining the production of a corresponding batch of books) during every production period (for example, every day). For this purpose, the scheduler 420 is used for configuring a job database 425 (action "A3.Configure"). The job database 425 (for example, managed by a company planning manager) contains a definition of all the processing stations that are available in the bookbinding plant; moreover, the job database 425 contains a descriptor for each job (which specifies its processing phases, the corresponding execution file 415, when the job should be executed, and possible execution constraints thereof). At the beginning of every day, the scheduler 420 processes the information in the job database 425 in order to create a corresponding workflow plan 430 (action "A4.Create"). The workflow plan 430 specifies a flow of execution of the jobs during the day, according to the execution requirements and constraints of the jobs, and to the availability of the needed processing stations. The workflow plan 430 is then executed (action "A5.Execute"); for example, the workflow plan 430 is printed and it is supplied to operators that move the semi-finished products accordingly, load them into the processing stations, and start the corresponding processing phases. The scheduler 420 also receives information relating to the operation of the various processing stations from an interface module 435 (which communicates with a controller - for example, a PLC - of each processing station); for example, such operation information indicates when the processing station has started a processing phase, has suffered a stop because of an error, or has ended a processing phase. The operation information is used by the scheduler 420 for updating the workflow plan 430 accordingly, so as to provide a real-time representation of the progress state of the plan (action "A6.Update").

[0034] In the solution according to an embodiment of the invention, the printing file 405 of each job and the job database 425 are also accessed by a population module 440. For each job (as defined in the job database 425), the population module 440 determines the representative images of each signature of the book from the corresponding printing file 405 (according to the processing information). Moreover, for each processing phase of the book (as defined in the job database 425), the population module 440 determines a set of one or more setting semi-finished products that indicate a setting of the corresponding processing station (for example, a first flat sheet loaded in the folding station, a first signature loaded in each hopper of the gathering station, a first signature loaded in the stacking station, a first signature loaded in the sewing station, and a first signature and a first cover loaded in the finishing station). The population module 440 then populates an image database 445, by adding a record for each job (action "A7.Populate"); for each semi-finished product, the record contains a pointer to its representative image in the printing file 405, and for each processing phase the record contains an indication of its setting semi-finished products. An enrichment module 450 may also be used for enriching each record in the image database 445 with additional information of the job (action "A8.Enrich"); for example, it is possible to add a job description, an identifier of an order which the job belongs to, a name of the respective customer, a title of the book, a number of exemplars of the book to be produced, and so on.

[0035] A synthesis module 455 synthesises the representative image of each semi-finished product in the image database 455 with a descriptor of the representative image (action "A9. Synthesize"). Preferably, for this purpose the synthesis module 455 identifies salient points of the representative image (for example, dots, segments and piecewise lines); a neighbourhood of each salient point in the representative image is represented by a corresponding descriptor, substantially invariant to position and brightness (for example, the known descriptors SIFT, Harris-Affine, SURF, and STAR). The descriptor of the representative image is then defined by the above-mentioned descriptors of its salient points.

[0036] An acquisition module (for the processing stations) 460 provides a digital image 465 (in the following, indicated as current image 465) of each semi-finished product being loaded in initial position in each processing station before the start of the corresponding processing phase (for example, a first flat sheet loaded in the folding station, a first signature loaded in each hopper of the gathering station, a first signature loaded in the stacking station, a first signature loaded in the sewing station, and a first signature and a first cover loaded in the finishing station); each current image 465 is received from the processing station, where it has been acquired by the corresponding camera (action "A10.Acquire").

[0037] A recognition module 470 recognizes the current image 465, by comparing it with all the representative images defined in the image database 445 (action "All.Recognise"). For this purpose, the recognition module 470 determines a synthesised descriptor of the current image 465 by applying the same algorithm used above for the representative images (i.e., with the descriptor of the current image 465 defined by the descriptors of its salient points). The descriptor of the current image 465 is then compared with the descriptors of the representative images in the image database 445; in case of a positive match (i.e., if the descriptor of the current image 465 corresponds to the descriptor of a representative image in the image database 445 with a tolerance defined by a corresponding threshold value for their difference), the semi-finished product represented by the current image 465 is recognized as an exemplar of the semi-finished product corresponding to such representative image in the image database 445. In this respect, it should be noted that the recognition algorithm at issue (based on the descriptors of the salient points) allows obtaining satisfactory results, despite the current images 465 generally differ in a rather substantial way from the representative images in the image database 445 (since the current images 465 are acquired from the semi-finished products with all the corresponding inaccuracies of the case, whereas the representative images in the image database 445 are obtained from digital images being perfect for their nature).

[0038] Moreover, such recognition algorithm is very robust, since it allows recognizing even current images 465 that are rotated (because of a movement of the corresponding semi-finished products) or partial (because of occlusions of the corresponding cameras). Obviously, the recognition of the current image 465 requires a non-negligible computation time (because of the relative complexity of the recognition algorithm and the normally high number of the representative images to be compared); however, this does not represent a problem in general, since the current images 465 in this case are acquired during the loading of the respective processing station (and not during the actual execution of the corresponding processing phase, when the processing time of each semi-finished product might instead be too short for the effective recognition of the corresponding digital image).

[0039] For each processing station that provides for a set of multiple setting semi-finished products, as defined in the image database 445 (for example, the gathering station and the finishing station), a verification module of 475 verifies whether a corresponding set of current images 465 correctly identifies such setting semi-finished products (action "A12.Verify"); for example, in the event of the gathering station it is verified whether the first signature that is loaded in each hopper is an exemplar of the signature that is expected in that hopper (for gathering the groups of signatures of the book correctly), while in the event of the finishing station it is verified whether the first signature and the first cover that are loaded therein correspond to the same book. In the negative case (or in the case of a missing recognition of one or more current images 465), the verification module 475 signals a corresponding setting error to the interface module 435 (action "A13.Signal error"); the interface module 435 transmits the error signalling to the controller of the corresponding processing station, which consequently outputs an alarm signal (for example, of acoustic type) and preferably displays an indication of the error and of the required correct condition (as indicated in the image database 445). In this way, it is possible to control the correct setting of each processing station in a simple and effective way (before the actual execution of the corresponding processing phase).

[0040] On the contrary, if the set of current images 465 correctly identifies the setting semi-finished products of the processing station or if the processing station provides for a single setting semi-finished product (for example, for the folding station, the stacking station and the sewing station), the verification module 475 determines a correct setting of the processing station (for the processing phase of the corresponding job); therefore, the verification module 475 signals the setting of the processing station for such job to the interface module 435 (action "A14.Signal setting"). Such information is used by the interface module 435 for signalling the job, which the processing phase refers to, that will be executed on the processing station to the scheduler 420, so as to allows the scheduler to update the workflow plan 430 accordingly when the processing phase is actual started (through the above-described action "A6.Update"). It should be noted that the desired result is obtained in a completely automatic way, without requiring any manual action (for example, for reading the barcode from the identification sheet of the pallet of semi-finished products supplied to the processing station).

[0041] The processing phase is further verified after its starting, in correspondence to a selected subset of its processing cycles (during each one of them a corresponding set of semi-finished products is processed - for example, a flat sheet in the folding station, a signature in each hopper of the gathering station, a group of signatures in the stacking station, a signature in the sewing station, and a signature and a cover in the finishing station); preferably, this happens every 10-20 processing cycles, as signalled in the workflow plan 430 (which counts the executed processing cycles from the start of the processing phase). In response to such signalling, the acquisition module 460 supplies the current image 465 of each semi-finished product under processing in the processing station for the processing cycle (same action "A10.Acquire").

[0042] The recognition module 470 recognizes the current image 465, by comparing it with the representative images of a set of verification semi-finished products that are expected in the processing station for the processing cycle; the verification semi-finished products are determined according to the content of the record of the job in the image database 445 (and possible according to the processing cycles already executed being indicated in the workflow plan 430) - for example, equal to the same setting flat sheet in the folding station, to the same setting signatures in the gathering station, to the same setting signature in the stacking station, to an expected signature according to a processing sequence thereof in the sewing station, and to the same setting signature and cover in the finishing station (same action "A11.Recognise"). In this respect, it should be noted that the recognition of each current image 465 requires a computation time lower than in the preceding case (since the number of representative images to be compared is limited to those of the verification semi-finished products); in any case, such computation time does not represent a problem in general, since the recognition of the current images 465 is not executed at every processing cycle (so that the operation may also complete during one or more next processing cycles).

[0043] The verification module 475 then verifies whether the current images 465 have all been correctly recognized (same action "A12.Verify"). In the negative case, the verification module 475 signals a corresponding processing error to the interface module 435 (same action "A13.Signal error"); as above, the interface module 435 transmits the error signalling to the controller of the corresponding processing station, which consequently outputs an alarm signal and preferably displays an indication of the error and of the required correct condition (as indicated in the image database 445). In this way, it is possible to control the correctness of the processing phase repeatedly during its execution.

[0044] In a completely asynchronous way, another acquisition module (for the palmtop computers) 480 supplies the current image 465 of a semi-finished product everywhere in the bookbinding plant (for example, on a pallet); each current image 465 is received from a palmtop computer, where it has been acquired manually by an operator through its camera (action "A10'.Acquire"). As above, the recognition module 470 recognizes the current image 465, by comparing it with all the representative images defined in the image database 445 (same action "A11.Ricognise"); in the case of positive verification (i.e., if the descriptor of the current image 465 corresponds to the descriptor of a representative image in the image database 445), the semi-finished product represented by the current image 465 is recognized as an exemplar of the semi-finished product corresponding to such representative image in the image database 445. An interrogation module 485 retrieves information relating to the job which the semi-finished product of the current image 465 belongs to from the image database 445 - for example, the job description, the identifier of the order which the job belongs to, the name of the respective customer and the title of the book, and possibly information relating to the progress state of the job as well from the workflow plan 430 - for example, the next processing phase to be executed (action "A15.Retrieve"). The interrogation module 485 returns the information corresponding to the current image 465 (or an error message in case of its missing recognition) to the corresponding palmtop computer for its display (action "A16.Return"). In this case as well, the desired result is obtained without requiring any additional manual operation (for example, for printing the identification sheets), with consequent reduction of costs and errors.

[0045] Naturally, in order to satisfy local and specific requirements, a person skilled in the art may apply to the solution described above many logical and/or physical modifications and alterations. More specifically, although this solution has been described with a certain degree of particularity with reference to one or more embodiments thereof, it should be understood that various omissions, substitutions and changes in the form and details as well as other embodiments are possible (for example, with respect to process parameters, materials and sizes). Particularly, different embodiments of the invention may even be practiced without the specific details (such as the numerical values) set forth in the preceding description to provide a more thorough understanding thereof; conversely, well-known features may have been omitted or simplified in order not to obscure the description with unnecessary particulars. Moreover, it is expressly intended that specific elements and/or method steps described in connection with any embodiment of the disclosed solution may be incorporated in any other embodiment as a matter of general design choice.

[0046] For example, similar considerations apply if the proposed solution is implemented with an equivalent method (by using similar steps, removing some steps being non-essential, or adding further optional steps); moreover, the steps may be performed in a different order, concurrently or in an interleaved way (at least in part).

[0047] Nothing prevents providing the printing information in any format, for use in any printers or even for the photolithography of printing photographic plates in the Computer To Plate (CTP) technique; likewise, the processing information may be of other type, provided that it is sufficient to determine the representative image of each semi-finished product among its digital images (for example, even only indicating the number of pages of each signature). Moreover, the processing and/or printing information may be provided in any other way (for example, in distinct files, with the processing information that is loaded manually into the image database, and the like).

[0048] Moreover, the above-mentioned recognition algorithm does not have to be interpreted in a limitative way (with the same result that may also be obtained with other techniques, compatible with the available computation powers and times).

[0049] The above-described examples of application of the proposed solution are merely indicative and in no way limitative. For example, the same information may also be used to control whether all the semi-finished products being loaded in a processing station belong to the same batch, to count the semi-finished products that have already undergone each processing phase for monitoring its progress state, and the like. Moreover, this also allows distinguishing the semi-finished products of different batches that are loaded without solution of continuity in a same processing station automatically (for example, in the sewing machines and in ring automatic feeders).

[0050] Naturally, it is possible to provide processing phases being similar, different, additional and/or alternative, or to detect the setting of some most critical processing stations only in an automatic way; moreover, nothing prevents implementing verifications being simpler (for example, based on the recognition of parts of the setting semi-finished products only) or more complex (for example, of matching among the semi-finished products being loaded in the processing station and the job that is expected in execution in the processing station).

[0051] Similar considerations apply to the verification of the correct setting of the processing stations.

[0052] Moreover, the verification of the processing phases may be executed with another timing (even non-periodic one) or in different way; for example, in the sewing station it is possible to acquire the current images of a group of signatures in succession and then compare them in order with the recognition images of the expected sequence of signatures. In any case, nothing prevents controlling all the processing cycles of each processing phase (in case a sufficient computation power is available).

[0053] Obviously, the integration of the proposed solution with the scheduler (for monitoring the progress of the jobs in an automatic way) is not strictly necessary, and it may be omitted in a simplified implementation (for example, when the jobs are managed in manual way).

[0054] Moreover, similar, different, additional and/or alternative information may be returned to the palmtop computers (or to equivalent components, also arranged at each processing station with a respective wired connection); the same functionality may also be integrated in the controller of each processing station, by exploiting the respective camera (for example, to obtain information about the job relating to the semi-finished products being loaded in the processing station). As above, such feature is merely optional, and it may be omitted in a simplified implementation.

[0055] The proposed solution lends itself to be used for controlling the production of batches of any other bookbinding product (for example, magazines); moreover, the bookbinding product may include any other semi-finished product or bookbinding element (like inserts, punched single sheets, and the like).

[0056] Similar considerations apply if the representative image of each semi-finished product is determined in another way - for example, through an algorithm that determines the front page of the signature based on the number of folds and on their type (parallel or crossing one), or conversely by simply setting it always equal to the first one of the digital images of the signature (in the hypothesis that it is always visible).

[0057] The proposed solution may be implemented as a stand-alone module, as a plug-in for the scheduler, or even directly in the scheduler itself. In any case, similar considerations apply if the program (which may be used to implement each embodiment of the invention) is structured in a different way, or if additional modules or functions are provided; likewise, the memory structures may be of other types, or may be replaced with equivalent entities (not necessarily consisting of physical storage media). The program may take any form suitable to be used by any data-processing system or in connection therewith (for example, within a virtual machine); particularly, the program may be in the form of external or resident software, firmware, or micro-code (either in object code or in source code - for example, to be compiled or interpreted). Moreover, it is possible to provide the program on any computer-usable medium. For example, the medium may be of the electronic, magnetic, optical, electromagnetic, infrared, or semiconductor type; examples of such medium are fixed disks (where the program may be pre-loaded), removable disks, tapes, cards, wires, fibres, wireless connections, networks, broadcast waves, and the like. In any case, the solution according to an embodiment of the present invention lends itself to be implemented even with a hardware structure (for example, integrated in a chip of semiconductor material), or with a combination of software and hardware suitably programmed or otherwise configured.

[0058] Similar considerations apply if the control system has a different structure or includes equivalent components (either separated from each other or combined together, in whole or in part).

[0059] Moreover, the control system may be used (in any number of exemplars) in any other bookbinding plant (in general, being manufactured and put on the market as a stand-alone product, in order to be used in pre-existing bookbinding plants).

Claims

1. A control method (A1-A16) for controlling a production of batches each one of a corresponding bookbinding product, the bookbinding product including a group of bookbinding elements each one having a plurality of pages, wherein for each batch the control method includes the steps of:

providing (A1-A2) printing information and processing information of the bookbinding product, the printing information including a digital image of each page of the bookbinding product, and the processing information including an indication of a composition of the bookbinding product in terms of the bookbinding elements and an indication of a composition of each bookbinding element in terms of the corresponding pages,

characterized by
determining (A7-A9) a representative digital image of each bookbinding element, the representative digital image of the bookbinding element being determined among the corresponding digital images according to the processing information, and
recognizing (A10-A16) each one of a set of selected exemplars of the bookbinding elements by acquiring a current digital image of the selected exemplar and comparing the current digital image with at least part of the representative digital images.

2. The control method (A1-A16) according to claim 1, wherein the processing information further includes a specification of a set of processing phases of the batch, the control method further including the step of:

determining (A7), for each processing phase, a set of setting bookbinding elements indicative of a setting of a processing station adapted to execute the processing phase, the setting bookbinding elements being determined according to the processing information,
and wherein the step of recognizing (A10-A16) each one of a set of selected exemplars includes, for each processing station:

acquiring (A10) the current digital image of each one of a set of initial exemplars of the bookbinding elements, the initial exemplars being loaded in an initial position in the processing station,

recognising (A11) each initial exemplar as an exemplar of a recognised setting bookbinding element in response to a matching of the current digital image of the initial exemplar with the representative digital image of the recognised setting bookbinding element, and

detecting (A12,A14) the setting of the processing station for the batch in response to the recognition of at least one of the initial exemplars.

3. The control method (A1-A16) according to claim 2, wherein the step of recognizing (A10-A16) each one of a set of selected exemplars further includes, for each processing station having a plurality of setting bookbinding elements:

detecting (A12,13) a setting error of the bookbinding station in response to at least one missing recognition of the initial exemplars.

4. The control method (A1-A16) according to claim 2 or 3, further including, for each processing station, the steps of:

detecting (A6) a starting of the processing station, and

detecting (A3-A6) a starting of the corresponding processing phase for the batch in response to the setting of the processing station for the batch and to the starting of the processing station.

5. The control method (A1-A16) according to claim 4, wherein each processing phase includes the repetition of a plurality of processing cycles, in response to the starting of each processing phase for the batch the step of recognizing (A10-A16) each one of a set of selected exemplars including, for each one of a subset of the processing cycles:

acquiring (A10) the current digital image of each one of a set of processing exemplars of the bookbinding elements, the processing exemplars being processed in the corresponding processing station for the processing cycle,

determining (A11) a set of verification bookbinding elements expected in the processing station for the processing cycle, the verification bookbinding elements being determined according to the processing information, and recognising each processing exemplar as an exemplar of a recognised verification bookbinding element in response to a matching of the current digital image of the processing exemplar with the representative digital image of the recognised verification bookbinding element, and

detecting (A12,13) a processing error of the bookbinding station in response to at least one missing recognition of the processing exemplars.

6. The control method (A1-A16) according to any claim from 1 to 5, further including the step of:

providing (A8) identification information of the batch, and wherein the step of recognizing (A10-A16) each one of a set of selected exemplars further includes:

acquiring (A10') the current digital image of a parked exemplar of the bookbinding elements in response to a manual acquisition command,

recognising (A11) the parked exemplar as an exemplar of a recognised bookbinding element in response to a matching of the current digital image of the parked exemplar with the representative digital image of the recognised bookbinding element,

retrieving (A15) the identification information of the batch of the recognised bookbinding element, and

displaying (A16) the retrieved identification information.

7. The control method (A1-A16) according to any claim from 1 to 6, wherein the bookbinding product is a book (170) and the bookbinding elements include signatures (125), each signature including a sheet (110) being folded at least once to define the corresponding pages.

8. The control method (A1-A16) according to claim 7, wherein the step of determining (A7-A9) a representative digital image of each bookbinding element includes, for each signature:

setting (A7-A9) the representative digital image of the signature to the digital image of a front page of the signature.

9. A software program (400) including code means for causing a control system (200) of a bookbinding plant (100) to perform the steps of the control method (A1-A16) according to any claim from 1 to 8 when the software program is executed on the control system.

10. A control system (200) for a bookbinding plant (100), the control system including means (400) for causing the control system to perform the steps of the method according to any claim from 1 to 8.

11. A bookbinding plant (100) including at least a control system (200) according to claim 10.

Drawing