CONTROL METHOD AND SYSTEM FOR SURFACE-SELECTIVE COATING OF AN INDIVIDUAL PHYSICAL DOCUMENT WITH A LIQUID COATING

Abstract

A method is provided for surface-selective coating of a surface of an individual physical document, in particular a card-like document, with a liquid coating. The method includes: receiving or generating an actual image information by image sensors, which represents an actual image of the surface; and comparing the actual image information with reference image information, which represents a reference image of a reference surface corresponding to the surface, to determine, based on possible deviations between the actual image and the reference image, any deformation of the surface compared to the reference surface and to generate deformation information representing said deformation or alternatively the absence thereof. A coating device is then controlled based on coating information determined based on the deformation information and on geometry information that defines a target shape of a partial surface of the surface to be provided with the liquid coating.

Claims

1. A method (100) for controlling a coating device (320) for surface-selective coating of a surface of an individual physical document (205) with a liquid coating, wherein the method (100) comprises: receiving (110) or generating by image sensors of actual image information representing an actual image (205A) of the surface; comparing (120) the actual image information with reference image information, which represents a reference image (225A) of a reference surface corresponding to the surface, in order to determine any deformation of the surface with respect to the reference surface based on any deviations between the actual image (205A) and the reference image (225A) and to generate deformation information representing said deformation or an absence thereof; determining (125, 130), depending on the deformation information and on geometry information (245, 250) which defines a target shape of a partial surface (255-1, 255-2, 255-3) of the surface to be provided with the liquid coating, a coating information (255) which defines an actual shape of a partial surface (255-1, 255-2, 255-3) of the surface to be coated by surface-selective liquid coating of the surface; and controlling (135) a coating device (320) in order to cause it to provide the surface of the document (205) with the liquid coating surface-selectively in accordance with the coating information (255) in the defined partial surface (255-1, 255-2, 255-3); wherein, when determining the coating information (255), the actual shape of the partial surface (255-1, 255-2, 255-3) is determined from the geometry information (245, 250) using a distortion of the target shape defined as a function of the deformation information in such a way that after the liquid coating has been carried out, an interaction of the actual shape of the coated partial surface (255-1, 255-2, 255-3) with the target shape of the surface in a region of the partial surface (255-1, 255-2, 255-3) at least partially compensates for the distortion.

2. The method (100) of claim 1, wherein the geometry information (245, 250) is at least partially obtained by image processing from the actual image information.

3. The method (100) of claim 1, wherein the geometry information (245, 250) is at least partially obtained by image processing from the reference image information.

4. The method (100) of claim 1, further comprising: determining the geometry information (245, 250) as a function of a result of an automatic analysis of a sample document (225) realizing the target shape on its surface or an image (225A) thereof using an analysis criterion characterizing the partial surface (255-1, 255-2, 255-3), wherein the analysis determines a shape of a surface region corresponding to the partial surface (255-1, 255-2, 255-3) on the sample document (225) or its image (225A) and defines it as the target shape.

5. The method (100) of claim 4, wherein the analysis criterion is or can be defined at least partially as a color-dependent criterion and the analysis involves determining the surface region by using the color-dependent criterion with regard to a color distribution on the sample document (225) or its image (225A).

6. The method (100) of claim 5, wherein the analysis comprises an evaluation of the color distribution in such a way that a region on the sample document (225) or its image, a color of which corresponds to a specified reference color according to the color-dependent criterion or is within a specified reference color range, is identified as a surface region corresponding to the partial surface (255-1, 255-2, 255-3).

7. The method (100) of claim 4, wherein the analysis criterion is defined at least in part as a surface structure-dependent criterion and the analysis involves determining the surface region by applying the surface structure-dependent criterion with respect to a surface structure of the sample document (225) or its image (225A).

8. The method (100) of claim 7, wherein the analysis comprises evaluating the surface structure in such a way that a region on the sample document (225) or its image, the surface structure of which corresponds to a predetermined structure according to the surface structure-dependent criterion or lies within a predetermined reference structure region, is identified as a surface region corresponding to the partial surface (255-1, 255-2, 255-3).

9. The method (100) of claim 4, wherein the determining of the target shape is carried out using a shape recognition process in order to recognize at least one shape element represented by the surface region from a predefined set of shapes as at least a partial target shape.

10. The method (100) of claim 9, wherein the shape recognition process comprises an optical character recognition, OCR, process to recognize at least one character represented by the surface region as at least a partial target shape.

11. The method (100) of claim 1, wherein the determining of the possible deformation of the surface compared to the reference surface and/or the determining of the coating information (255) takes place using a machine-learning-based process trained for this purpose.

12. The method (100) of claim 1, wherein the determining of the possible deformation of the surface compared to the reference surface comprises determining a type and/or extent of the deformation of the surface and the coating information (255) is determined as a function of the type and/or extent of the deformation determined in this way.

13. The method (100) of claim 1, wherein: the coating information (255) is determined on the basis of an image portion (220) of the actual image (205A) which contains the partial surface (255-1, 255-2, 255-3) but does not include at least one other region of the actual image (205A); and the image portion (220) is determined as a function of a determined variability of the actual shape within an ensemble of several earlier executions of the method using documents of the same type as document (205).

14. The method (100) of claim 1, wherein the determining of the coating information (255) comprises an aligning of the actual shape of the partial surface to be coated (255-1, 255-2, 255-3) represented by the coating information (255) with respect to an orientation of the surface to be coated surface-selectively, which orientation is present during application of the liquid coating.

15. The method (100) of claim 1, wherein: determining the coating information (255) comprises creating print data which define a print layout (255) for the surface-selective liquid coating of the surface in a region of the determined partial surface (255-1, 255-2, 255-3); and the coating device (320) is controlled as a function of the print data in order to cause the coating device (320) to provide the surface surface-selectively with the liquid coating by printing in the region of the surface associated to the partial surface (255-1, 255-2, 255-3) in the print layout (255).

16. The method (100) of claim 15, wherein creating the print data comprises converting a coloring already defined by the actual image information or newly defining a coloring, in each case for the print layout (255).

17. The method (100) of claim 1, wherein a document (205) which has already been preprinted or preformed in a controlled manner on the surface is used as the document (205) to be provided with the liquid coating.

18. The method (100) of claim 1, wherein a card-like document (205) is used as the document (205) to be provided with the liquid coating.

19. A system for surface-selective coating a partial surface (255-1, 255-2, 255-3) of a surface of an individual physical document (205) with a liquid coating, wherein the system comprises: a data processing device; and a coating device (320), which can be controlled by the data processing device (310a, 310b), for selective liquid coating of surfaces; wherein the data processing device (310a, 310b) is configured to carry out a method (100) comprising: receiving (110) or generating by image sensors of actual image information representing an actual image (205A) of the surface; comparing (120) the actual image information with reference image information, which represents a reference image (225A) of a reference surface corresponding to the surface, in order to determine any deformation of the surface with respect to the reference surface based on any deviations between the actual image (205A) and the reference image (225A) and to generate deformation information representing said deformation or an absence thereof; determining (125, 130), depending on the deformation information and on geometry information (245, 250) which defines a target shape of a partial surface (255-1, 255-2, 255-3) of the surface to be provided with the liquid coating, a coating information (255) which defines an actual shape of a partial surface (255-1, 255-2, 255-3) of the surface to be coated by surface-selective liquid coating of the surface; and controlling (135) a coating device (320) in order to cause it to provide the surface of the document (205) with the liquid coating surface-selectively in accordance with the coating information (255) in the defined partial surface (255-1, 255-2, 255-3); wherein, when determining the coating information (255), the actual shape of the partial surface (255-1, 255-2, 255-3) is determined from the geometry information (245, 250) using a distortion of the target shape defined as a function of the deformation information in such a way that after the liquid coating has been carried out, an interaction of the actual shape of the coated partial surface (255-1, 255-2, 255-3) with the target shape of the surface in a region of the partial surface (255-1, 255-2, 255-3) at least partially compensates for the distortion, the data processing device thereby controlling the coating device (320) according to the method in order to cause it to coat the surface of the document (205) according to the coating information (255) to be provided with the liquid coating surface-selectively in the defined partial surface (255-1, 255-2, 255-3).

20. A computer program or computer program product, each with instructions which, when executed on a computer (310a, 310b) or on a multi-computer platform, cause it to perform a method (100) comprising: receiving (110) or generating by image sensors of actual image information representing an actual image (205A) of the surface; comparing (120) the actual image information with reference image information, which represents a reference image (225A) of a reference surface corresponding to the surface, in order to determine any deformation of the surface with respect to the reference surface based on any deviations between the actual image (205A) and the reference image (225A) and to generate deformation information representing said deformation or an absence thereof; determining (125, 130), depending on the deformation information and on geometry information (245, 250) which defines a target shape of a partial surface (255-1, 255-2, 255-3) of the surface to be provided with the liquid coating, a coating information (255) which defines an actual shape of a partial surface (255-1, 255-2, 255-3) of the surface to be coated by surface-selective liquid coating of the surface; and controlling (135) a coating device (320) in order to cause it to provide the surface of the document (205) with the liquid coating surface-selectively in accordance with the coating information (255) in the defined partial surface (255-1, 255-2, 255-3); wherein, when determining the coating information (255), the actual shape of the partial surface (255-1, 255-2, 255-3) is determined from the geometry information (245, 250) using a distortion of the target shape defined as a function of the deformation information in such a way that after the liquid coating has been carried out, an interaction of the actual shape of the coated partial surface (255-1, 255-2, 255-3) with the target shape of the surface in a region of the partial surface (255-1, 255-2, 255-3) at least partially compensates for the distortion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

[0053] FIG. 1 schematically shows a flowchart to illustrate an exemplary embodiment of the method according to one embodiment of the invention.

[0054] FIG. 2 shows a schematic sequence of intermediate states of a document to be coated, corresponding to the method from FIG. 1.

[0055] FIG. 3 shows a schematic black box illustration of an exemplary embodiment of a system for carrying out a method such as the method from FIG. 1.

DETAILED DESCRIPTION

[0056] In the figures, the same reference numbers denote the same, similar or corresponding elements. Elements depicted in the figures are not necessarily represented to scale. Rather, the various elements shown in the figures are presented in such a way that their function and general purpose can be understood by those skilled in the art. Connections and couplings, shown in the figures, between functional units and elements can also be implemented as an indirect connection or coupling, unless expressly stated otherwise. Unless specifically stated otherwise, functional units can be implemented in particular as hardware, software or a combination of hardware and software.

[0057] FIG. 1 illustrates an exemplary embodiment 100 of the method for controlling a coating device for surface-selectively coating a surface of an individual physical document with a liquid coating. For this purpose, FIG. 2 illustrates a sequence 200 of different intermediate states that are reached as part of the method 100. For this reason, reference is also made to FIG. 2 in the description of method 100.

[0058] As part of method 100, reference image information is generated in a process 105 based on an in particular card-like sample document 225 (or an image, in particular photos thereof), which information, as reference image 225A, represents an image of a reference surface serving as an error-free reference of sample document 225. The reference image information or the reference image 225A can be obtained in particular by (digital) photographing the surface of the sample document, preferably in the form of digital image data.

[0059] The reference image 225A shows a pre-printed background image 230, a representation of an electronic chip 235, which is integrated in the sample document, as well as an identifier composed of a text element 240-1, and a graphic element 240-2, which identifier is present on a plurality, in particular several different documents v to be coated according to the method. For example, this can be the name and a logo of an issuer of the document, for example in the case of a bank or credit card of a bank or a credit card company.

[0060] In a further process 115a, the two image elements 240-1 (text element) and 240-2 (graphic element) are extracted from the reference image 225A by image processing using a color-dependent analysis criterion. According to the analysis criterion, the image elements 240-1 and 240-2 to be extracted are characterized by a certain predefined color (shown as black surface in the figures), which differs from the color of the background image 230. Instead of a single color, a specific color range in a defined color space (such as RGB) can also be used as a color-dependent analysis criterion, so that only image elements are extracted, the coloring of which lies within this color range.

[0061] Alternatively or cumulatively with a color-dependent analysis criterion, a surface structure-dependent analysis criterion can also be used, so that only surface regions or image elements which have a surface structure detected by sensors, which correspond to a specified surface structure (such as roughness or material property) or lie within a specified reference structure region, are extracted as image elements or surface regions to be coated.

[0062] In addition, alternatively or cumulatively, a form recognition process can be used in order to recognize at least one form element represented in the reference image 225A from a predefined set of forms as at least a partial target form. This makes sense in particular with regard to the recognition of text elements or other predefined characters or character chains (such as using OCR technology), in which case the range of shapes (alphabet, for example) can serve as an analysis criterion.

[0063] In process 115a, geometry information 245 is generated using the analysis criterion, which information represents, for example in the form of a layout, these two image elements 240-1 and 240-2 and their respective position and orientation within reference image 225A (in the form of corresponding data). The image elements 240-1 and 240-2 at least partially define a target shape (in particular form) of a partial surface of the surface of at least one document 205 to be provided with a liquid coating, but typically of a plurality of such documents 205 of the same type. The target shape accordingly comprises here at least the two non-contiguous surface regions 240-1 and 240-2.

[0064] The processes 105 and 115a can in particular be carried out before the further process steps described below.

[0065] The method 100 also comprises a process 110 in which image information (actual image information) is generated by image sensors with a vision system (in particular a camera) or is received in the form of image data from a data source, wherein the image information represents an image (actual image) 205A of a relevant surface of a document 205 to be coated.

[0066] The actual image 205A has a pre-printed background image 210, a representation of an electronic chip 215, which is integrated in the document 205, as well as an identifier composed of a text element 220-1, and a graphic element 220-2, which identifier is present on a plurality, in particular several different documents 205 to be coated according to the method. For example, as in sample document 225, this can be the name and a logo of an issuer of the document, for example in the case of a bank or credit card of a bank or a credit card company. In addition, the actual image 205A contains a further image element 220-3, which is document-specific information (in particular personalization) that is not already present on the sample document 225 or its image 225A. The actual image 205A thus differs from the reference image 225A at least by the image element 220-3. A further difference, however, in the present example of FIG. 2 is that due to a deformation of the surface of the document 205, the image elements 220-1 to 220-3 in a plan view of the document 205 and correspondingly in its image (actual image) 205A appear distorted (illustrated here by a skewing of the picture elements), while they appear undistorted in the reference image 225A.

[0067] In a first embodiment variant of the method 100, the actual image 205A is compared with the reference image 225A as part of a process 120a in order to be able to use any deviations to infer a potential deformation of the document 205 or its surface compared to a flat shape. In the present example, the distortions in the actual image 205A with regard to the image elements 220-1 and 220-2 compared to the corresponding image elements 240-1 or 240-2 are recognized and a type and extent of a corresponding deformation is reconstructed and used as the resulting deformation information (in data form). This can be done in particular by a suitably adapted machine-learning-based process, such as using a suitably trained artificial neural network.

[0068] In a further process 115b, similar to process 115a, such image elements 220-1 to 220-3 which correspond to the analysis criterion are extracted using an analysis criterion which can correspond in particular to that from process 115a.

[0069] According to a second embodiment variant of the method 100, instead of the process 120a, a process 120b takes place to compare the geometric data 245 resulting from the process 115a with the geometric data 250 resulting from the process 115b in order to correspondingly, as described above, recognize a potential deformation of the document 205 and to generate corresponding deformation information. The use of process 120b instead of process 120a has the advantage that the comparison can already be carried out on the basis of the extracted image elements and thus without taking into account the full complexity of images 225A and 205A including their other image contents (210, 215, 230, 235).

[0070] The target shape of the liquid coating to be produced is then obtained by combining the geometric information 245 and 250, so that the target shape contains the image elements 240-1, 240-2 and additionally the image element 220-3. It should be pointed out that depending on the application and embodiment of the method, the target shape can also be derived exclusively from the geometry information 245 or from the geometry information 250 or can be defined thereby. The former makes sense in particular when only surface regions of the document 205 are to be coated which are already represented by corresponding image elements in the reference image 225A, while the latter is particularly relevant when surface regions are to be coated with document-specific information. Insofar as mutually corresponding image elements are contained in the two items of geometry information 245 and 250, preferably only one of them is adopted in each case in order to avoid duplication.

[0071] In a further process 125, in particular on an optical basis, an orientation of the document 205 to be coated relative to the coating device used for its coating can be detected by sensors. Thus, in particular, any deviation from a target alignment can be recognized and taken into account in a further process 130 in the subsequent definition of a coating information 255 that defines a coating layout.

[0072] In the process 130, the previously obtained geometry information defining the target shape, the determined orientation of the document 205 and the deformation information serve as input variables. As a result, the process 130 supplies the coating information 255, which in particular represents a coating layout for a liquid coating to be applied to the document 205 by a coating device. Depending on the deformation information, as part of process 130, image elements 220-1 to 220-3 are included in the image information or in the coating layout in such a distorted form that this distortion at least partially compensates the deformation-related distortion of these image elements in actual image 205A or in the geometry information 250 (similar to how a barrel distortion as counter-distortion can compensate an original pincushion distortion). The generation of the coating information can, in particular, also include a conversion in the sense that a coloring of the partial surface to be coated that is optionally contained in the geometry information and is defined by the actual image information is converted into a different coloring, in particular black/white or shades of gray, in order to control the application of the liquid coating. The new coloring can then encode in particular a location-dependent variable thickness of the liquid coating to be applied or a coloring of the same.

[0073] A further process 135 follows, in which a coating device is controlled in accordance with the coating information in order to provide the surface of the document 205 with a liquid coating in accordance with the coating layout. The coated document 260 thus results in that the original deformation-related distortion of the image elements 220-1 to 220-3 is at least partially, ideally as here completely, compensated (cf. undistorted image elements 260-1 to 260-3).

[0074] The target shape of the liquid coating to be produced is then obtained by combining the geometric information 245 and 250, so that the target shape contains the image elements 240-1, 240-2 and additionally the image element 220-3. It should be pointed out that depending on the application and embodiment of the method, the target shape can also be derived exclusively from the geometry information 245 or from the geometry information 250 or can be defined thereby. The former makes sense in particular when only surface regions of the document 205 are to be coated which are already represented by corresponding image elements in the reference image 225A, while the latter is particularly relevant when surface regions are to be coated with document-specific information.

[0075] In a further process 125, in particular on an optical basis, an orientation of the document 205 to be coated relative to the coating device used for its coating can be detected by sensors. Thus, in particular, any deviation from a target alignment can be recognized and taken into account in a further process 130 in the subsequent definition of a coating information item 255 that defines a coating layout.

[0076] In the process 130, the previously obtained geometry information defining the target shape, the determined orientation of the document 205 and the deformation information serve as input variables. As a result, the process 130 provides the coating information 255, which in particular represents a coating layout for a liquid coating to be applied to the document 205 by a coating device and defines a shape (actual shape) of the surface regions to be coated (combined: partial surface). Depending on the deformation information, as part of process 130, image elements 220-1 to 220-3 are included in the image information or in the coating layout in such a distorted form that this distortion at least partially compensates the deformation-related distortion of these image elements in the actual image 205A or in the geometry information 250 (similar to how a barrel distortion as counter-distortion can compensate an original pincushion distortion). Also this process 130 can be performed in particular by a suitably adapted machine-learning-based process, such as using a suitably trained artificial neural network.

[0077] A further process 135 follows, in which a coating device is controlled in accordance with the coating information in order to provide the surface of the document 205 with a liquid coating in accordance with the coating layout. The coated document 260 thus results in that the original deformation-related distortion of the image elements 220-1 to 220-3 is at least partially, ideally as here completely, compensated (cf. undistorted image elements 260-1 to 260-3). The surface-selective coating takes place here only in the region of the surface regions representing the image elements 255-1 to 255-3 (collectively: partial surface), while the other regions of the surface of the document 260 resulting from the coating from document 205 remain uncoated.

[0078] Optionally, only one further process 140 can follow, in that a limited image portion 220 is identified in the actual image on the basis of the results of process 115b, within which the image elements 220-1 to 220-3 extracted according to the analysis criterion lie. This image portion 220 can now be defined as an image analysis region for subsequent further method executions with regard to further documents in such a way that the process 115b is carried out there only with regard to this limited image analysis region. The process 140 can also be defined in such a way that it refers to an entire ensemble of previous executions of the process 115b including the last process run carried out in relation to document 205 and defines the image analysis region based on a plurality, in particular all, of the corresponding image portions from this ensemble of process runs. The process 140 is or can be defined accordingly in particular in such a way that the currently determined image portion is compared with an image portion resulting from earlier process runs of this process, and an adjustment of the image portion only takes place if the last determined image portion extends beyond the image portion resulting from earlier process runs.

[0079] Finally, FIG. 3 illustrates an exemplary system 300 for performing the method 100 comprising a coating process controlled according to the process 135 itself.

[0080] The system 300 has a plurality of modules 305 to 325 connected in series within the framework of a processing path and is configured in particular to carry out the method 100. A first module is configured as an input module 305 and is used to receive the documents to be coated, which can be supplied in particular as a stack of documents, and then to supply them individually to the next module 310 for further processing. Furthermore, the input module 305 can also be configured to receive a sample document 225 and to supply it to the module 310. For this purpose, either the same transport route can be used as for documents 205, or a separate, dedicated transport route for sample documents 225 can be used.

[0081] Module 310 is a module configured for image acquisition and process control. In particular, it can have a processor platform 310a with one or more processors, an associated program and data memory 310b and an image sensor system (in particular a camera) 310c for generating the actual image information and the reference image information. A computer program is stored in the memory 310b, which is designed and configured to be executed on the processor platform 310a in order to control the system 300 in such a way that it executes the method 100. The processor platform 310a and the data storage together form a data processing device.

[0082] The next module 315 along the processing path is configured as a module for chip coding of the chip 215 on the document 205. In particular, this can be done using contacts or wirelessly, depending on the type of document 205 and/or the corresponding communication capability of the system 300.

[0083] The further module 320 follows along the processing path, which is configured, under corresponding control by the computer program, to carry out a surface-selective liquid coating (including application and curing of the coating, in particular by irradiation with ultraviolet light (UV)) of the document 205. The module 320 accordingly represents a coating device within the meaning of the method 100 and can be configured in particular for printing the document 205 with the liquid coating, for example as an inkjet printer.

[0084] The next module is a module 325 for quality control, which in turn can have an image sensor system, such as a photo or video camera, in order to capture and check the coated documents 260 (see FIG. 2) using an image sensor for quality control purposes.

[0085] Finally, there follows an output module 330 for the coated documents 260, which can be configured in particular in such a way that, depending on the results of the quality control carried out in module 325, it outputs error-free documents on the one hand and faulty documents on the other hand, in different ways. In particular, documents with errors can be ejected from the process flow before the documents recognized as being error-free are output, which can in particular include a stacking of the documents to be output.

[0086] While at least one exemplary embodiment has been described above, it is to be noted that a large number of variations thereto exist. It is also to be noted that the exemplary embodiments described only represent non-limiting examples, and are not intended to restrict the scope, the applicability, or the configuration of the devices and methods described herein. Rather, the preceding description will provide those skilled in the art with guidance for implementing at least one exemplary embodiment, wherein it is apparent that various changes in the operation and arrangement of elements described in an exemplary embodiment may be made without departing from the scope of the subject matter defined in the appended claims and its legal equivalents.