Field of Invention

The present invention relates to an image processing system and to a method for generating control signals for printing means, from source image data from an image source.

Background

In prior art image processing systems, when generating a ready-to-print file or bitmap from source image data from an image source, a ready-to-print file is generated for the full width of the printing apparatus or for a lane of a plurality of lanes covering the full width. Such a ready-to-print file is sent to a streaming processor in order to generate control signals for the printing means based on the ready-to-print file.

In an exemplary application where such image processing systems are used, various different labels may be needed for the same product. More in particular, brand packaging is getting more personal and the use of variable labels for the same product is becoming more common. E.g. Coca- Cola's cans and bottles featuring common first names are part of a growing trend. Typically, these various different labels need to be applied to the products in a random manner. The obvious solution consists in printing the various labels in order, e.g. first labels "A", next labels "B", etc., sticking the labels to the products in order, sorting the products by hand into random batches in the warehouse, and then shipping them out to stores. However, such a solution is expensive and time consuming.

US 8,830,513 discloses a method for storing a destination document from a source document, typically a PDF document. Recurring content in the source document is flattened and stored in a first memory location, and then for each page in the source document, the page is flattened using the variable and the (stored) recurring content, and portions influenced by the variable content are extracted and stored in a second memory location. For each page, a new page is added to the destination document comprising the flattened, recurring content stored in the first memory location and the flattened, variable content stored in the second memory location. Using such a method a flattened PDF or PDF/VT document can be generated with recurring content stored in the form of XObjects. Such a document can be passed to a RIP (Raster Image Processor), and the RIPping of form XObjects can be optimized during caching. Although the efficiency is improved by performing the flattening, such a method suffers from the fact that the RIP will have to generate a bitmap for every page of the flattened PDF or PDF/VT document. Summary

An object of embodiments of the invention is to provide an image processing system and method for obtaining printed images and in particular labels which may be used in a random manner in a more convenient manner.

According to a first aspect of the invention, there is provided an image processing system for generating control signals for printing means, from source image data from an image source. The source image data represents a plurality of images to be printed, and the plurality of images comprising at least a first image and a second image. The image processing system comprises a raster image processing and randomizing module and a streaming processor. The raster image processing and randomizing module is configured to convert said source image data into a plurality of bitmaps and to determine order information defining an ordered array of elements, wherein each element contains a reference to a bitmap of said plurality of bitmaps. The plurality of bitmaps comprises at least a first bitmap corresponding with the first image and a second bitmap corresponding with the second image. The elements are arranged by the raster image processing and randomizing module in a random order in the array, wherein the total number of elements in the array referring to the first bitmap corresponds with the total number of first images to be printed, wherein the total number of elements in the array referring to the second bitmap corresponds with the total number of second images to be printed, and wherein the total number of elements in the array corresponds with the total number of the plurality of images to be printed. The streaming processor is configured to generate control signals for the printing means based on said plurality of bitmaps and said order information.

By determining order information in the image processing system at the level of the raster image processing, a random order can be directly determined for the bitmaps. On the contrary, in prior art solutions for printing various images in one print job, the images are usually put in a predetermined order in an upfront authoring tool, wherein a printer language (e.g. PDF) or a variable data printer language (e.g. PDF/VT) explicitly prescribes the predetermined order. In embodiments of the invention the bitmaps are shuffled at the raster image processing level, leading to a faster and more efficient processing with a reduced amount of data compared to prior art solutions.

In an exemplary embodiment the raster image processing and randomizing module is configured to determine the random order using a shuffle algorithm. This may be a truly random shuffle algorithm or a random shuffle algorithm using a feed or initial value. Shuffling is the process of rearranging an array of elements randomly. A shuffling algorithm may be unbiased (without a feed, truly random), where every ordering is equally likely. An example thereof is the Fisher-Yates shuffling algorithm. Some other possible shuffling algorithms use a feed or initial value and procedure the same random order if the feed is not changed.

In an exemplary embodiment the array comprises a plurality of rows and a plurality of columns, wherein a column thereof refers to bitmaps intended to be printed adjacent to each other, seen in a print direction of the printing means, and wherein a row thereof refers to bitmaps intended to be printed adjacent to each other, seen a direction perpendicular on the print direction of the printing means. In an exemplary embodiment the source image data comprises any one or more of the following files:

a multipage file comprising a plurality of pages containing the first image and one or more pages containing the second image;

a plurality of single-page files comprising at least a first single page file containing the first image and a first copy count for the first image and a second single page file containing the second image and a second copy count for the second image;

a combination of a multipage file comprising a plurality of pages containing the first image and a single -page file containing the second image and a second copy count for the second image.

In case of a multipage file, for each page of the multipage file there may be generated a bitmap. In case of multiple single-page files, for each single -page file there may be generated a bitmap.

In an exemplary embodiment the source data is included in a single-page or multi-page PDF or PDF/VT file.

In an exemplary embodiment the streaming processor is further configured to receive instruction signals and to use said instruction signals for generating additional printing marks, such as cut marks or a calibration strip, in a printed image. In an exemplary embodiment the order information is included in a file in a descriptive language, e.g. an .xml file or a .txt file.

Embodiments of the invention are both applicable with inkjet heads as well as with light heads such as a LED array, and more generally, with any printing means. In an exemplary embodiment the raster image processing and randomizing module is configured to link the place of each element in the determined ordered array to a unique identifier of the said element. To support tracking of the printed result, while determining the order, a link can be made of the order of each bitmap with a unique identifier of the bitmap. This link can be saved, exported or stored in e.g. a database. This is useful if the printed result needs to be verified after the printing. An exemplary application where such an embodiment may be useful is printing of lottery tickets.

According to a second aspect of the invention, there is provided an image processing for generating control signals for printing means, from source image data from an image source. The source image data represents a plurality of images to be printed, said plurality of images comprising at least a first image and a second image. The image processing method comprises raster image processing the source image data to covert the source image data in a plurality of bitmaps comprising at least a first bitmap corresponding with the first image and a second bitmap corresponding with the second image, and determining order information defining a randomly ordered array of elements, wherein each element contains a reference to a bitmap of said plurality of bitmaps, wherein the elements are arranged in a random order in said array. The total number of elements in the array referring to the first bitmap corresponds with the total number of first images to be printed, the total number of elements in the array referring to the second bitmap corresponds with the total number of second images to be printed, and the total number of elements in the array corresponds with the total number of the plurality of images to be printed. The image processing method further comprises generating control signals for the printing means based on said plurality of bitmaps and said order information. The generating may be directly or indirectly (via intermediate bitmap elements, see further) based on said plurality of bitmaps and said order information.

In an exemplary embodiment of the method, the random order is determined using a shuffle algorithm which may be any one of the shuffle algorithms discussed above.

In an exemplary embodiment of the method, the array comprises a plurality of rows and a plurality of columns; wherein a column thereof refers to bitmaps intended to be printed adjacent to each other, seen in a print direction of the printing means; and wherein a row thereof refers to bitmaps intended to be printed adjacent to each other, seen a direction perpendicular on the print direction of the printing means. In an exemplary embodiment of the method, the source image data comprises any one or more of the following files: a multipage file comprising a plurality of pages containing the first image and one or more pages containing the second image; a plurality of single -page files comprising at least a first single page file containing the first image and a first copy count for the first image and a second single page file containing the second image and a second copy count for the second image; a combination of a multipage file comprising a plurality of pages containing the first image and a single-page file containing the second image and a second copy count for the second image. The source data may be included e.g. in a single-page or multi-page PDF or PDF/VT file.

In an exemplary embodiment of the method, the order information is included in a file in a descriptive language.

According to another aspect there is provided a digital data storage medium encoding a machine- executable program of instructions to perform any one of the embodiments of the method disclosed above. Brief description of the figures

The accompanying drawings are used to illustrate presently preferred non-limiting exemplary embodiments of devices of the present invention. The above and other advantages of the features and objects of the invention will become more apparent and the invention will be better understood from the following detailed description when read in conjunction with the accompanying drawings, in which:

Figure 1 is block diagram of a printing and cutting arrangement including an exemplary embodiment of an image processing system;

Figure 2 illustrate schematically a detailed view of a RIP and randomizing module of an exemplary embodiment of an image processing system; and

Figure 3 is flow chart of an exemplary embodiment of an image processing method.

Description of embodiments

Figure 1 illustrates a printing and cutting arrangement including an embodiment of an image processing system of the invention. The image processing system comprises a raster image processing and randomizing module 120 and a streamer 130. The printing and cutting arrangement further comprises a printing means 140 and a cutting means 150.

For the description of an exemplary embodiment below, it is assumed that images II, 12, 13 need to be printed 10, 1000 and 100 times, respectively, and that the printed images II (xlO), 12 (xlOOO), 13 (xlOO) should be mixed at random for further use. The raster image processing and layout module 120 comprises an input interface for receiving source image data representing a plurality of images to be printed. The plurality of images comprises at least a first image II and a second image 12. In the present example it is assumed that the plurality of images comprises images II (xlO), 12 (xlOOO), 13 (xlOO). The source image data may be included e.g. in:

a multipage file comprising a plurality of pages containing the first image and one or more pages containing the second image; e.g. a multipage file comprising 10 pages with II, 1000 pages with 12, and 100 pages with 13;

- a plurality of single-page files comprising at least a first single page file containing the first image and a first copy count for the first image and a second single page file containing the second image and a second copy count for the second image; e.g. a first single page file containing the first image II and a first copy count 10, a second single page file containing the second image 12 and a second copy count 1000, and a third single-page file containing the second image 13 and a third copy count 100;

a combination of a multipage file comprising a plurality of pages containing the first image and a single -page file containing the second image and a second copy count for the second image. The raster image processing and randomizing module 120 is configured to convert the source image data of images II, 12, 13 into a series of bitmaps Bl, B2, B3. The raster image processing and randomizing module 120 is further configured to determine order information O defining an ordered array of elements, wherein each element contains a reference to a bitmap of said plurality of bitmaps Bl, B2, B3. The elements are arranged in a random order in said array. The total number of elements in the array referring to the first bitmap B 1 corresponds with the total number of first images II to be printed, i.e. 10 in the example. The total number of elements in the array referring to the second bitmap B2 corresponds with the total number of second images 12 to be printed, i.e. 1000 in the example. The total number of elements in the array referring to the third bitmap B3 corresponds with the total number of third images 13 to be printed, i.e. 100 in the example. In the example, the generated order information may be e.g. 3 x B2; lx B l ; 10 x B2; 1 x B3; etc.

Assuming that three images can be printed next to each other in a width direction perpendicular on the print direction, these bitmaps Bl, B2 and B3 together with the order information will lead to the printing of the following pattern on the substrate S:

12 12 12 11 12 12

12 12 12

12 12 12

12 12 13

Etc.

To generate the random order of the bitmaps B l, B2, B3 a shuffle algorithm is implemented in the software of the RIP and randomizing module 120. This will be discussed in more detail below with reference to figure 2.

Optionally the raster image processing and randomizing module 120 may also generate cut-out contour data comprising one or more cut-out contours from the source data J. The cut-out contour data is generated to match the bitmaps B l, B2, B3. Optionally the raster image processing and randomizing module 120 may further generate information about the space between two consecutive bitmaps, the position of a first included bitmap with respect to a second included bitmap, etc.

The raster image processing and randomizing module 120 further comprises an output interface for making the bitmaps Bl, B2, B3 and the order information O available to the streamer 130. The streaming processor or streamer 130 is arranged to receive the bitmaps B l, B2, B3, optionally together with position signals PS comprising information on position data for said bitmaps B 1 , B2, B3 in the printed image. The streaming processor 130 is configured to generate control signals CS for the printing means 140 based on the bitmaps B l, B2, B3 and the order information, optionally using the position signals PS. Optionally the streaming processor 130 may be further configured to receive instruction signals IS and to use the instruction signals IS for generating the control signals CS. Those instruction signals IS may relate to the adding of marks, such as cut marks or other data, or to calibration operations.

As shown in figure 2, the RIP and randomizing module 120 comprises a raster image processing (RIP) part 121 which extracts the relevant data from the source image data and produces corresponding raster images also known as a bitmaps Bl, B2, B3. The input of the RIP and randomizing module 120, i.e. the source image data J, may be a page description in a high-level page description language such as PostScript, Portable Document Format (PDF), Portable

Document Format for variable and transactional printing (PDF/VT), XPS or another bitmap. In the latter case, the RIP applies either smoothing or interpolation algorithms to the input bitmap to generate the output bitmap Bl, B2, B3. Raster image processing is the process of turning e.g. vector digital information such as a PostScript file into a high-resolution raster image. RIPs may be implemented through hardware generating a hardware bitmap which is used to enable or disable each pixel on a real-time output device such as an optical film scanner. However, usually a RIP is implemented either as a software component of an operating system or as a firmware program executed on a microprocessor inside. According to a variant a stand-alone hardware RIP may be used. In a preferred embodiment the raster image processing (RIP) part 121 is capable of converting images in single-page or multipage PDF or PDF/VT documents in bitmaps.

As shown in figure 2, the RIP and randomizing module 120 further comprises a shuffle part 122 for extracting the quantities of the images II, 12, 13 (10 x II, 1000 x 12, 100 x 13) from the source data, and for performing a shuffle algorithm to determine the random order in which the images need to be printed.

In yet other non-illustrated embodiments, bitmap elements may be generated with the bitmaps Bl, B2, B3 and the order information O. For example lane bitmap elements each containing a series of bitmaps to be printed in a lane of the substrate may be generated and passed to the streamer. E.g. a first lane bitmap element could contain images to be printed in a first lane (e.g. B2 B l B2 B2 B2, etc.), a second lane bitmap element could contain images to be printed in a second lane (e.g. B2 B2 B2 B2 B2, etc.), and a third lane bitmap element could contain image to be printed in a third lane (e.g. B2 B2 B2 B2 B3). The first lane, the second lane, and the third lane extend in a printing direction and correspond with adjacent lanes in a printed image. More details about lane printing can be found in European patent application with application number EP 13176488.8 in the name of the Applicant, which is included herein by reference. Particular embodiments of the invention relate to the field of digital printing systems for so-called "continuous" webs, i.e. printing systems where a continuous roll of substrate (e.g. , paper, plastic foil, or a multi-layer combination thereof) is run through the printer, in particular to print large numbers of copies of the same image(s), or alternatively, series of images, or even large sets of individually varying images, wherein a random order is required. When these continuous webs have to be subjected to a subsequent mechanical cut-out operation (e.g., to cut contours in the top layer of a multi-layer substrate, so as to produce peel-off adhesive labels), it is conventional to define the cut-out pattern as a plate which repetitively imposes the same cut-out pattern onto the relevant portion of the passing substrate. The same logic is presently being applied to laser cutters, which do not use a physical roll with cutting edges, but which nevertheless use a cutting pattern defined as a single "plate area" which is repeatedly applied. Figure 3 illustrates an exemplary embodiment of an image processing method for generating control signals for printing means, from source image data from an image source. The source image data represents a plurality of images to be printed, comprising at least a first image and a second image, and e.g. a multipage file (e.g. PDF or PDF/VT) comprising a plurality of pages containing the first image and one or more pages containing the second image; or a plurality of single-page files comprising at least a first single page file containing the first image and a first copy count for the first image and a second single page file containing the second image and a second copy count for the second image. The image processing method comprises in a first step 301 the receiving of the source image data. In a second step 302, the source data is raster image processed to covert the source image data in a plurality of bitmaps comprising at least a first bitmap corresponding with the first image and a second bitmap corresponding with the second image. Also in the second step 302 order information defining an ordered array of elements is determined, wherein each element of the array contains a reference to a bitmap of said plurality of bitmaps, and wherein said elements are arranged in a random order in said array. The total number of elements in the array referring to the first bitmap corresponds with the total number of first images to be printed; the total number of elements in the array referring to the second bitmap corresponds with the total number of second images to be printed; and the total number of elements in the array corresponds with the total number of the plurality of images to be printed. It is noted that said converting and said determining may be performed one after the other or simultaneously, i.e. the converting may be performed before or after the determining or at the same time. The order information may be included in a file in a descriptive language, e.g. an .xml file or a .txt file. In a third step 303 control signals for the printing means are generated directly or indirectly based on said plurality of bitmaps and said order information. In the exemplary embodiment of figure 1 the generating is directly based on said plurality of bitmaps and said order information. However, in other non-illustrated embodiments a plurality of bitmap elements grouping a plurality of bitmaps in a certain order in each bitmap element may be used to generate the control signals, in which case the control signals are indirectly based on said plurality of bitmaps and said order information. In step 304, the printing is performed using the control signals.

In step 302 the random order may be determined using a shuffle algorithm. This may be a truly random shuffle algorithm which provides a different order when used with the same source image input data, or a random shuffle algorithm with a so-called feed, which results in the same order when used with the same source image input data and the same feed. Depending on the desired application one or the other may be preferred. A person of skill in the art would readily recognize that some steps of various above described methods can be performed by programmed computers. Herein, some embodiments are also intended to cover program storage devices, e.g., digital data storage media, which are machine or computer readable and encode machine executable or computer-executable programs of instructions, wherein said instructions perform some or all of the steps of said above-described methods. The program storage devices may be, e.g., digital memories, magnetic storage media, hard drives, or optically readable digital data storage media. The embodiments are also intended to cover computers programmed to perform said steps of the above -described methods.

The functions of the various elements shown in the figures, including any functional blocks labeled as "processors" or "modules", may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term "processing module" should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), and non volatile storage. Other hardware, conventional and/or custom, may also be included.

Whilst the principles of the invention have been set out above in connection with specific embodiments, it is to be understood that this description is merely made by way of example and not as a limitation of the scope of protection which is determined by the appended claims.