Methods, apparatus, printing systems and computer-readable storage media for printing curved surfaces

Abstract

This application discloses a curved surface printing method, apparatus, printing system, and computer-readable storage medium. A controller uses a height acquisition device to acquire the height of a first curved surface medium that has moved to a acquisition position, obtaining height information corresponding to the printing surface of the first curved surface medium. Based on the height information, the controller determines the curvature information of the printing surface of the first curved surface medium. The controller then adjusts the number of pixels in the first printed image according to the curvature information to obtain a second printed image. Based on the second printed image, the controller controls one or more nozzles of the printing apparatus to print on the first curved surface medium that has moved to the first station. The controller adjusts the number of pixels in the first printed image according to the curvature information to obtain the second printed image, ensuring that the printing frequency of the nozzles matches the curvature information. This guarantees that the distribution of printed dots in the printed pattern on the first curved surface medium based on the second printed image is uniform, i.e., the resolution is similar, thus ensuring printing quality.

Description

Technical Field

[0001] This application relates to the field of inkjet printing technology, specifically to a curved surface printing method, apparatus, printing system, and computer-readable storage medium. Background Technology

[0002] Inkjet printing technology refers to the technology of spraying ink droplets onto a printing medium through a printhead to obtain images or text. This technology is non-contact printing and has advantages such as high printing speed, low pollution, vibrant image colors, long image preservation time, and adaptability to various printing media.

[0003] When inkjet printing on curved printing media, traditional inkjet printing methods can result in uneven ink droplet spacing and distribution, leading to poor print quality. Summary of the Invention

[0004] This application discloses a curved surface printing method, apparatus, printing system, and computer-readable storage medium, which makes the spacing between ink dots of the printed pattern on the first curved surface medium similar, thereby improving the quality of curved surface printing.

[0005] This application discloses a curved surface printing method applied to a controller of a printing system. The printing system further includes a height acquisition device, a transfer device, and a printing device. The transfer device carries a first curved surface medium and first transfers the first curved surface medium to the acquisition position corresponding to the height acquisition device, and then transfers the first curved surface medium to the first station corresponding to the printing device. The printing surface of the first curved surface medium includes a curved surface. The method includes:

[0006] The height of the first curved medium that has been moved to the acquisition position is acquired by the height acquisition device, and the height information corresponding to the printing surface of the first curved medium is obtained.

[0007] Based on the height information, the curvature information of the printing surface of the first curved medium is determined;

[0008] The number of pixels in the first printed image is adjusted according to the curvature information to obtain the second printed image;

[0009] Based on the second printed image, one or more nozzles of the printing device are controlled to print the first curved medium that has moved to the first station.

[0010] As an optional implementation, adjusting the number of pixels in the first printed image according to the curvature information to obtain the second printed image includes:

[0011] Based on the curvature information, the first printed image is divided into multiple image regions;

[0012] Based on the height change information of the printed surface corresponding to each of the image regions, determine the adjustment ratio corresponding to each of the image regions;

[0013] The number of pixels contained in each of the image regions is adjusted according to the adjustment ratio corresponding to each of the image regions to obtain the second printed image.

[0014] As an optional implementation, the height information includes height data corresponding to multiple points on the printed surface, and the height change information corresponding to the printed surface of the image region includes the slope of the printed surface corresponding to the image region; the method further includes:

[0015] Determine the highest and lowest points of the printed surface corresponding to the first image region; wherein, the highest point is the point with the largest height data in the printed surface corresponding to the first image region, and the lowest point is the point with the smallest height data in the printed surface corresponding to the first image region; the first image region is any one of the plurality of image regions;

[0016] Based on the image position of the highest point in the first image area, the height data of the highest point, the image position of the lowest point in the first image area, and the height data of the lowest point, the slope of the printed surface corresponding to the first image area is determined.

[0017] As an optional implementation, the transfer device carries the first curved medium and moves it at a constant speed along a first direction; the step of adjusting the number of pixels contained in each of the image regions according to the adjustment ratio corresponding to each of the image regions to obtain the second printed image includes:

[0018] According to the adjustment ratio corresponding to each of the image regions, interpolation processing is performed on each of the image regions in the first printed image along the first direction to obtain a second printed image; wherein, the ratio between the number of pixels in each of the image regions in the second printed image along the first direction and the number of pixels in the corresponding image region in the first printed image along the first direction is the adjustment ratio corresponding to the corresponding image region.

[0019] As an optional implementation, the printing system further includes an image acquisition device; the method further includes:

[0020] The image acquisition device acquires an image of the first curved medium that has moved to the acquisition position, thereby obtaining a first image.

[0021] Based on the first image, determine the deviation pose information of the first curved medium from the target pose;

[0022] Obtain a reference printed image that matches the target pose;

[0023] Based on the deviation pose information, the reference printed image is transformed to obtain a first printed image that matches the first curved surface medium.

[0024] As an optional implementation, the first curved surface medium is provided with one or more markers; the step of determining the deviation pose information of the first curved surface medium from the target pose based on the first image includes:

[0025] Identify each marker in the first image and determine the image position of each marker in the first image;

[0026] Based on the image positions corresponding to each of the markers, the first pose corresponding to the first curved medium is determined.

[0027] Determine the deviation pose information between the first pose and the target pose.

[0028] As an optional implementation, the first curved medium is provided with a first marker and a second marker, the first pose includes first position information and first angle information corresponding to the midpoint between the first marker and the second marker, and the target pose includes target position information and target angle information corresponding to the midpoint;

[0029] Determining the deviation pose information between the first pose and the target pose includes:

[0030] Determine the deviation position information between the first position information and the target position information;

[0031] Determine the deviation angle information between the first angle information and the target angle information.

[0032] This application discloses a curved surface printing device, applied to a controller of a printing system. The printing system further includes a height acquisition device, a transfer device, and a printing device. The transfer device carries a first curved surface medium and first transfers the first curved surface medium to the acquisition position corresponding to the height acquisition device, and then transfers the first curved surface medium to the first station corresponding to the printing device. The printing surface of the first curved surface medium is curved. The curved surface printing device includes:

[0033] The height acquisition module is used to acquire the height of the first curved medium that has moved to the acquisition position through the height acquisition device, and obtain the height information corresponding to the printing surface of the first curved medium;

[0034] The curvature determination module is used to determine the curvature information of the printing surface of the first curved medium based on the height information;

[0035] An image adjustment module is used to adjust the number of pixels in the first printed image according to the curvature information to obtain a second printed image; and

[0036] The printing control module is used to control one or more nozzles of the printing device to print the first curved medium that has moved to the first station, based on the second printed image.

[0037] This application discloses a printing system, including:

[0038] Altitude acquisition device;

[0039] Printing device;

[0040] A transfer device is used to carry a first curved surface medium and first transfer the first curved surface medium to the acquisition position corresponding to the height acquisition device, and then transfer the first curved surface medium to the first station corresponding to the printing device, wherein the printing surface of the first curved surface medium includes a curved surface; and

[0041] The controller includes a memory and a processor. The memory stores a computer program, which, when executed by the processor, causes the processor to implement any of the surface printing methods disclosed in the embodiments of this application.

[0042] This application discloses a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements any of the surface printing methods disclosed in this application.

[0043] Compared with related technologies, the embodiments of this application have the following beneficial effects:

[0044] This application provides a curved surface printing method, apparatus, printing system, and computer-readable storage medium. The method is applied to a controller of a printing system, which further includes a height acquisition device, a transfer device, and a printing device. The transfer device carries a first curved surface medium and first transfers the medium to the acquisition position corresponding to the height acquisition device, then transfers it to a first station corresponding to the printing device. The printing surface of the first curved surface medium includes a curved surface. The controller acquires the height of the first curved surface medium at the acquisition position using the height acquisition device, obtaining height information corresponding to the printing surface of the medium. Based on the height information, the controller determines the curvature information of the printing surface of the medium, adjusts the number of pixels in the first printed image according to the curvature information to obtain a second printed image, and controls one or more nozzles of the printing device to print the first curved surface medium at the first station based on the second printed image. The controller adjusts the number of pixels in the first printed image according to the curvature information to obtain the second printed image, so that the printing frequency of the nozzles matches the curvature information, ensuring that the distribution of printing points of the printed pattern on the first curved medium is uniform based on the second printed image, that is, the resolution is similar, thus ensuring printing quality. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the structure of a printing system disclosed in an embodiment of this application;

[0047] Figure 2 This is one of the embodiments disclosed in this application. Figure 1 A magnified view of a section at point A in the middle;

[0048] Figure 3 This is one of the embodiments disclosed in this application. Figure 1 A magnified view of a section at point B in the middle;

[0049] Figure 4 This is a schematic diagram of the positioning component from another perspective disclosed in an embodiment of this application;

[0050] Figure 5 This is one of the embodiments disclosed in this application. Figure 1 A magnified view of a section at point C;

[0051] Figure 6 This is a schematic diagram of the bottom of a printhead disclosed in an embodiment of this application;

[0052] Figure 7 This is a schematic diagram of a printing process disclosed in an embodiment of this application;

[0053] Figure 8 This is a schematic flowchart of a surface printing method disclosed in an embodiment of this application;

[0054] Figure 9 This is a schematic diagram illustrating the correspondence between pixels of a printed image and print points on a printed surface, as disclosed in an embodiment of this application.

[0055] Figure 10 This is a schematic flowchart of a second printed image acquisition process disclosed in an embodiment of this application;

[0056] Figure 11 This is a schematic flowchart of a first printed image acquisition process disclosed in an embodiment of this application;

[0057] Figure 12 This is a schematic diagram of the first pose corresponding to a first printing medium disclosed in an embodiment of this application;

[0058] Figure 13 This is a flowchart illustrating a pose deviation information determination process disclosed in an embodiment of this application;

[0059] Figure 14 This is a flowchart illustrating another pose deviation information determination process disclosed in an embodiment of this application;

[0060] Figure 15 This is a schematic diagram of the structure of a curved surface printing apparatus disclosed in an embodiment of this application;

[0061] Figure 16 This is a schematic diagram of the structure of a controller for a printing system disclosed in an embodiment of this application. Detailed Implementation

[0062] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0063] It should be noted that the terms "comprising" and "having," and any variations thereof, in the embodiments and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0064] Please refer to Figure 1 This illustrates a schematic diagram of the structure of a printing system provided in an embodiment of this application. Figure 1 As shown, the printing system may include a transfer device 110, a positioning assembly 120, a printing device 130, and a controller. Figure 1 (Not shown in the image). The positioning component 120 may include an image acquisition device, and the transfer device 110 carries the printing medium to be printed, first transferring the printing medium to the acquisition position corresponding to the image acquisition device, and then transferring the printing medium to the first station corresponding to the printing device 130. The image acquisition device can be used to acquire an image of the first curved surface medium moved to the acquisition position to obtain a first image. The printing device 130 can be used to print the printing medium moved to the first station. Optionally, please refer to... Figure 1 The transfer device is used to drive the printing medium to move along the first direction X.

[0065] In some embodiments, please refer to Figure 1 The transfer device 110 may include an adsorption fixture 111 and a linear motor 112. The linear motor 112 extends along a first direction X, and the adsorption fixture 111 is used to fix the printing medium on the adsorption fixture 111 by vacuum adsorption.

[0066] Alternatively, please refer to Figure 2 The transfer device may also include a connecting fastener 210 and a fixture mounting support 220. The fixture mounting support 220 is used to provide a mounting surface for the adsorption fixture 111. That is, the adsorption fixture 111 is mounted on the fixture mounting support 220. The connecting fastener 210 is connected to the linear motor 112 and the fixture mounting support 220 respectively to ensure a stable connection between the linear motor 112 and the adsorption fixture 111, and to enable the adsorption fixture 111 to run along the first direction X under the drive of the linear motor 112.

[0067] Alternatively, please continue to refer to Figure 2 The transfer device may also include a vacuum display 230, which displays the vacuum adsorption value between the adsorption fixture 111 and the printing medium. When the vacuum adsorption value is greater than a preset threshold, it can be considered that the printing medium has been well adsorbed and can be relatively stably positioned on the adsorption fixture.

[0068] In some embodiments, please refer to Figure 3 It shows Figure 1 A magnified view of a section at point B. (See image below.) Figure 3 As shown, the positioning assembly may include an image acquisition device 310, a first gantry column 320, and an image acquisition mounting bracket 330. The first gantry column 320 provides a mounting base surface for other components of the positioning assembly. The image acquisition mounting bracket 330 is fixedly connected to both the first gantry column 320 and the image acquisition device 310, so that the image acquisition device 310 is mounted on the first gantry column 320, and the printing medium passes under the image acquisition device 310 under the drive of a linear motor.

[0069] Optionally, the positioning component may include multiple image acquisition devices 310 to acquire images of the complete printing medium. These image acquisition devices can scan the position and outline of the printing medium to obtain a two-dimensional image of the printing medium, providing positioning and location data for subsequent product printing.

[0070] In some embodiments, the positioning component may further include a light source assembly 340 and a light source mounting member 350, wherein the light source mounting member 350 is connected to the first gantry column 320 and the light source assembly 340 respectively, so as to mount the light source 340 on the first gantry column 320. The light source assembly 340 can be used to provide brightness supplementary lighting for the image acquisition device 310.

[0071] Please refer to Figure 4 It shows a schematic diagram of the positioning component from another perspective, such as Figure 4 As shown, the printing system may also include a height acquisition device 410 and a height sensing mounting component 420. The height sensing mounting component 420 is connected to the first gantry column 320 and the height acquisition device 410, respectively. The printing medium passes under the height acquisition device 410 under the drive of a linear motor, and the height acquisition device 410 can be used to acquire the distance between the printing surface of the printing medium and the height acquisition device 410.

[0072] Optionally, the height acquisition device 410 is installed on the first side of the first gantry column 320 via the height sensing mounting component 420, and the image acquisition device is installed on the second side of the first gantry column via the image acquisition mounting component. The first side and the second side are opposite sides. By setting the height acquisition device 410 and the image acquisition device on different sides of the first gantry column 320, the space of the first gantry column 320 can be fully utilized.

[0073] Please refer to Figure 5 It shows Figure 1 A magnified view of a section at point C. (See image below.) Figure 5As shown, the printing device may include a second gantry column 510, a print head 520, and a printing mounting component 530. The printing mounting component 530 is connected to the second gantry column 510 and the print head 520 respectively. The printing medium passes under the print head 520 under the drive of a linear motor, and the print head 520 prints the pattern onto the printing medium that has moved to the first station.

[0074] Please refer to Figure 6 This shows a bottom schematic diagram of a printhead provided in an embodiment of this application. Figure 6 As shown, the printhead may include multiple nozzles 610, which are arranged in one or more rows along the second direction Y. Each nozzle 610 can operate independently, meaning that each nozzle 610 can independently select whether to spray ink. Figure 6 As shown, the printhead includes 8 rows of nozzles, and the spacing between adjacent rows of nozzles can be equal or unequal.

[0075] Please refer to Figure 7 This illustration shows a schematic diagram of a printing process provided in an embodiment of this application. Figure 7 As shown, the length of the print head 710 along the second direction Y is greater than or equal to the length of the printing medium 720 along the second direction Y, thereby ensuring that the pattern can be printed on the corresponding position of the printing medium 720 by the print head 710 during the movement of the printing medium 720 along the first direction, without any printing blind spots.

[0076] Please refer to Figure 8 The diagram illustrates a flow chart of a curved surface printing method provided in an embodiment of this application. This method can be applied to the controller of a printing system. The printing system also includes a height acquisition device, a transfer device, and a printing device. The transfer device carries a first curved surface medium and first transfers the first curved surface medium to the acquisition position corresponding to the height acquisition device, and then transfers the first curved surface medium to the first station corresponding to the printing device.

[0077] like Figure 8 As shown, the surface printing method includes steps 802 to 808.

[0078] Step 802: The height of the first curved medium that has been moved to the acquisition position is acquired by the height acquisition device to obtain the height information corresponding to the printing surface of the first curved medium.

[0079] It should be noted that the first curved medium may refer to the medium to be printed on, and the printing surface of the first curved medium includes a curved portion, and may also include a flat portion. For example, the printing medium may include, but is not limited to, cups, lenses, etc. Height information can be used to characterize the distance between the printing surface of the first curved medium and the bearing surface of the transfer device. The height information may include height data corresponding to multiple points on the printing surface of the first curved medium, and the height data corresponding to each point includes the distance between that point and the bearing surface. The printing system may include one or more height acquisition devices, such that the scanning range of the multiple height acquisition devices along the second direction covers the first curved medium along the second direction, so as to avoid missing any distance between the printing surface and the height acquisition device. Optionally, the height acquisition device may include, but is not limited to, a laser sensor or an ultrasonic sensor.

[0080] For example, a height acquisition device scans the first curved surface medium moved to the acquisition position to obtain distance information between the printing surface of the first curved surface medium and the height acquisition device. Based on the distance information, the height information between the printing surface and the bearing surface of the transfer device is determined. It should be noted that the bearing surface of the transfer device can refer to the surface of the transfer device that contacts the first curved surface medium. The height acquisition device can be used to detect the distance between the printing surface of the first curved surface medium and the height acquisition device, and the distance information can be used to characterize the distance between the printing surface of the first curved surface medium and the height acquisition device. The controller can pre-store the distance between the height acquisition device and the bearing surface, and determine the height information between the printing surface and the bearing surface of the transfer device based on the distance information and the distance between the height acquisition device and the bearing surface.

[0081] For example, the height acquisition device can detect the distance between the printed surface of the first curved medium and the height acquisition device along a third direction, wherein the third direction is perpendicular to both the first and second directions. For example, the height acquisition device may include a laser sensor that emits a laser along a third direction to detect the distance between the printed surface and the height acquisition device along that third direction.

[0082] Step 804: Determine the curvature information of the printing surface of the first curved medium based on the height information.

[0083] It should be noted that curvature information can be used to characterize the degree of curvature of the printing surface of the first curved medium. Curvature information may include the curvature corresponding to multiple points on the printing surface of the first curved medium. The controller can determine the curvature corresponding to multiple points on the printing surface of the first curved medium based on the height data corresponding to these multiple points.

[0084] In some embodiments, the height data corresponding to each point in the printed surface includes a first distance between the point and the bearing surface, and the curvature information includes the curvature corresponding to multiple points of the printed surface. Determining the curvature information of the printed surface of the first curved medium based on the height information may include: the controller determining the three-dimensional coordinates corresponding to multiple points of the printed surface based on the image positions of multiple points of the printed surface in the first image and the first distances corresponding to the multiple points, determining the surface function corresponding to the printed surface based on the three-dimensional coordinates corresponding to the multiple points, and determining the curvature corresponding to multiple points of the printed surface based on the surface function.

[0085] Step 806: Adjust the number of pixels in the first printed image according to the curvature information to obtain the second printed image.

[0086] It should be noted that the pose of the first printed image matches the pose of the first curved medium. That is, based on the first printed image, one or more nozzles of the printing device are controlled to print on the first curved medium moved to the first station. This ensures that the position and size of the pattern printed on the first curved medium meet the requirements. The greater the curvature, the greater the degree of bending of the printed surface, and the greater the difference between the length of the printed surface and the length of its projection in the first direction. Please refer to [reference needed]. Figure 9 Line segment AB has a length of L in the first direction X, and line segment BC also has a length of L in the first direction X. The length of line segment AB is greater than the length of line segment BC. Pixels A', B', and C' in the first printed image correspond to points A, B, and C in the first printing medium, respectively. The distance between pixels A' and B' in the first printed image, and the distance between pixels B' and C', are both L. However, in the pattern printed on the first printing medium, the distance between points A and B, and the distance between points B and C, are obviously different, resulting in different resolutions on the printed surface of the first curved medium. In this embodiment, the number of pixels in the first printed image is adjusted according to the curvature information, thereby adjusting the jetting frequency of the nozzle. This makes the jetting frequency match the curvature information, reducing the phenomenon of changes in the distance between various printed points in the pattern caused by the curved surface, ensuring the resolution of the pattern on the printed surface, and guaranteeing print quality. For example, if a printing point D is added between point A and point B, the distance between point A and point D, the distance between point D and point B, and the distance between point B and point C can all be equal, making the resolution of the pattern on the first curved medium uniform. By adding a pixel D' to the first printed image, a printing point can be formed at point D on the printing medium.

[0087] For example, the greater the curvature of the printed surface indicated by the curvature information, the more pixels the resulting second printed image has. It should be noted that when the curvature of the printed surface is greater, the number of additional pixels in the first printed image increases, thereby increasing the jetting frequency of one or more nozzles of the printing device controlled according to the second printed image, so as to make the resolution of the pattern printed on the first curved medium uniform.

[0088] For example, if the curvature of the printed surface indicated by the curvature information is less than or equal to a curvature threshold, the number of pixels contained in the first printed image does not need to be adjusted. It should be noted that the pixel threshold can be used to measure whether the printed surface is close to a plane. If the curvature is greater than the curvature threshold, the printed surface is considered curved; if the curvature is less than or equal to the curvature threshold, the printed surface is considered close to a plane. By not adjusting the number of pixels contained in the first printed image when the curvature is less than or equal to the curvature threshold, the spacing between the printed dots in the printed pattern can be kept uniform while reducing the computational load on the controller.

[0089] In some embodiments, adjusting the number of pixels in a first printed image based on curvature information to obtain a second printed image may include: a controller performing an interpolation operation on the first printed image based on curvature information to increase the number of pixels in the first printed image, thereby obtaining the second printed image. It should be noted that the interpolation operation refers to calculating new pixel values ​​based on existing pixel values ​​to fill blank areas in the first printed image. Through interpolation, new pixels can be inserted between rows or columns of the first printed image, making the pixels of the printed pattern in the second printed image denser. In this embodiment, by inserting new pixels, the jetting frequency of the nozzles is increased, thereby increasing the number of printed dots on the printing surface, which can reduce the problem of uneven ink dot spacing caused by curvature and improve print quality.

[0090] Step 808: Based on the second printed image, control one or more nozzles of the printing device to print the first curved medium that has moved to the first station.

[0091] It should be noted that the number of pixels in the adjusted second printed image changes, increasing the number of pixels and thus increasing the printing frequency of the print head. This means that, relative to printing the second printed image, the spacing between the printed dots on the first curved medium decreases, resulting in more uniform resolution on the curved printing surface. The second printed image includes multiple pixels, which are used to indicate when one or more nozzles of the print head eject ink at a target time. The controller can read the pixel values ​​corresponding to each row and column of pixels in the second printed image and determine the control signals for each nozzle of the printing device based on these pixel values. This drives the nozzles to perform printing operations at the corresponding times, i.e., ejecting ink droplets, so that the landing points of the multiple ink droplets ejected by one or more nozzles correspond one-to-one with the multiple pixels of the second printed image. The first curved medium moves along a first direction. Ink ejected by the nozzles at different times can form ink dots at different positions along the first curved medium along the first direction. At the same time, selecting different nozzles to eject ink can print ink dots at different positions along the second direction on the first curved medium.

[0092] In some embodiments, the print head of the printing device remains stationary while printing on the first curved medium that has moved to the first station. The width of the print head along the second direction is greater than or equal to the width of the first curved medium, thereby ensuring that printing on the first curved medium can be achieved even when the print head of the printing device is not moving, and that ink droplets can land on the corresponding positions on the first curved medium.

[0093] In some embodiments, a first voltage is provided to the printing device to determine the landing point distance between the landing point position of the ink droplets ejected from the nozzles of the printhead and the target landing point position. If the landing point distance is less than or equal to a preset threshold, the first voltage is used as a trigger voltage. If the landing point distance is greater than the preset threshold, the parameters of the first voltage are adjusted to obtain an adjusted first voltage, and the operation of providing the first voltage to the printing device continues.

[0094] It should be noted that different parameters of the first voltage result in different jet speeds and droplet sizes. Adjusting the parameters of the first voltage can minimize the deviation of the droplet landing position, thus improving printing accuracy. The parameters of the first voltage may include the voltage amplitude, voltage pulse width, and voltage waveform (e.g., square wave, trapezoidal wave, sine wave, etc.). For example, the point furthest from the printhead can be selected for testing. Figure 7 If the trigger voltage can cause the corresponding nozzle to spray at the corresponding time, and the sprayed ink can accurately land at point B, then the nozzle will be triggered to spray based on the trigger voltage, and the landing distance at other positions will also be less than the preset threshold.

[0095] In some embodiments, the ejection time of each nozzle is determined based on the second printed image, and a driving voltage is formed based on the nozzle time and the trigger voltage. The driving voltage is provided to the printing device to control one or more nozzles to print on the first curved medium that has moved to the first station, so that a pattern that meets the printing requirements can be formed on the printing surface of the first curved medium.

[0096] In this embodiment, the controller uses a height acquisition device to acquire the height of the first curved medium that has moved to the acquisition position, obtaining the height information corresponding to the printing surface of the first curved medium. Based on the height information, the controller determines the curvature information of the printing surface of the first curved medium. Based on this curvature information, the controller adjusts the number of pixels in the first printed image to obtain a second printed image. Based on the second printed image, the controller controls one or more nozzles of the printing device to print on the first curved medium that has moved to the first station. The controller adjusts the number of pixels in the first printed image based on the curvature information to obtain the second printed image, ensuring that the printing frequency of the nozzles matches the curvature information. This guarantees that the distribution of printing dots in the printed pattern on the first curved medium is uniform, i.e., the resolution is similar, thus ensuring printing quality.

[0097] Please refer to Figure 10 This illustration shows a flowchart of a second printed image acquisition process provided in an embodiment of this application. The height information includes height data corresponding to multiple points on the printing surface of the first curved medium. For example... Figure 10 As shown, adjusting the number of pixels in the first printed image according to the curvature information to obtain the second printed image may include steps 1002 to 1006.

[0098] Step 1002: Divide the first printed image into multiple image regions based on the curvature information.

[0099] It should be noted that the printing surface includes media areas that correspond one-to-one with multiple image areas, and the image areas are used to control the printing device to print on the corresponding media areas.

[0100] For example, the multiple pixels contained in the image area are used to indicate the printing parameters corresponding to multiple points in the media area corresponding to the image area, such as the color of the printing point and whether an ink droplet needs to be formed at that point (i.e. whether printing is required). The denser the pixels in the image area that indicate that printing is required, the denser the printing points in the media area corresponding to the image area.

[0101] For example, among multiple points in the medium region corresponding to the same image region, the difference between the maximum curvature and the minimum curvature is less than the curvature threshold. That is, the curvature difference between any two points in the same medium region is very small, thereby ensuring that the number of pixels contained in the adjusted image region is adapted to the curvature of the medium region, and ensuring that the resolution of the printed pattern meets the requirements.

[0102] In some embodiments, the printing surface of the first printing medium is divided into multiple medium regions according to curvature information, and the first printing image is divided into multiple image regions corresponding one-to-one with the multiple medium regions according to the correspondence between the printing surface and the first printed image.

[0103] Step 1004: Determine the adjustment ratio for each image region based on the height change information of the printed surface corresponding to each image region.

[0104] It should be noted that the height change information corresponding to the printed surface of the image area may refer to the height change information of the media area corresponding to the image area. This height change information of the media area can be used to describe the changing trend of height data of multiple points in the media area, or height differences, etc. Optionally, the height change information of the media area may include, but is not limited to, the slope, curvature, and height gradient of the media area. The adjustment ratio corresponding to the image area may refer to the ratio between the number of pixels in the image area of ​​the second printed image that indicate the need for printing and the number of pixels in the image area of ​​the first printed image that indicate the need for printing.

[0105] In some embodiments, the height information includes height data corresponding to multiple points on the printed surface, and the height change information corresponding to the printed surface of the image area includes the slope of the printed surface corresponding to the image area. The controller can determine the highest point and the lowest point of the printed surface corresponding to the first image area, and determine the slope of the printed surface corresponding to the first image area based on the image position of the highest point in the first image area, the height data corresponding to the highest point, the image position of the lowest point in the first image area, and the height data corresponding to the lowest point.

[0106] It should be noted that the first image region can be any one of multiple image regions. The highest point is the point with the largest height data in the printed surface corresponding to the first image region, and the lowest point is the point with the smallest height data in the printed surface corresponding to the first image region. In other words, the highest point is the point in the media region corresponding to the first image region that is closest to the height acquisition device, and the lowest point is the point in the media region corresponding to the first image region that is farthest from the height acquisition device. Both the height data and the image position of the first image region correspond to points on the media region. The greater the slope of the media region, the more printing points need to fall within that media region.

[0107] In some embodiments, the slope of the printed surface may include the slope of the printed surface along a first direction. This is based on the image position of the highest point in the first image area and the height data corresponding to the highest point. 、 The image position corresponding to the lowest point in the first image area and the height data corresponding to the lowest point are used to determine the slope of the printed surface corresponding to the first image area. This can include the controller determining a first value in the first image position and a second value in the second image position, calculating the positional difference between the first value and the second value, calculating the height difference between the height data corresponding to the highest point and the height data corresponding to the lowest point, calculating the ratio of the height difference to the positional difference, and determining this ratio as the slope of the medium area corresponding to the first image area. Here, the first image position is the image position corresponding to the highest point in the first image area, the second image position is the image position corresponding to the lowest point in the first image area, the first value is the coordinate value of the first image position corresponding to the first direction, and the second value is the coordinate value of the second image position corresponding to the first direction.

[0108] In some embodiments, determining the adjustment ratio for each image region based on the height change information of the printed surface corresponding to each image region may include: the controller determining the adjustment ratio for each image region based on the slope of the printed surface corresponding to each image region. For example, the adjustment ratio is... in, ΔH represents the slope of the printed surface corresponding to the image area, ΔH represents the height difference between the height data corresponding to the highest point and the height data corresponding to the lowest point in the first image area, and ΔL represents the positional difference between the first value and the second value in the first image area.

[0109] Step 1006: Adjust the number of pixels in each image region according to the adjustment ratio corresponding to each image region to obtain the second printed image.

[0110] In some embodiments, the transfer device carries a first printing medium and drives the first printing medium to move at a constant speed along a first direction. The number of pixels in each image region is adjusted according to the adjustment ratio corresponding to each image region to obtain a second printed image. This may include: a controller performing interpolation processing on each image region in the first printed image along the first direction according to the adjustment ratio corresponding to each image region to obtain the second printed image. The ratio between the number of pixels in each image region of the second printed image along the first direction and the number of pixels in the corresponding image region of the first printed image along the first direction is the adjustment ratio corresponding to the corresponding image region. That is, the controller performs interpolation processing on the second image region along the first direction according to the adjustment ratio corresponding to the second image region to obtain the second printed image. The ratio between the number of pixels in the second image region of the second printed image along the first direction and the number of pixels in the second image region of the first printed image along the first direction is the adjustment ratio corresponding to the second image region, which can be any one of multiple image regions.

[0111] It should be noted that the transfer device moves at a constant speed along the first direction. To ensure the quality of the ink droplets at the printed points, the speed of the transfer device is generally not very fast. Therefore, if the printing surface of the first curved medium is curved along the first direction, uneven spacing between the printed points will occur. In this embodiment, by adjusting the number of pixels contained in each image region, the frequency at which the print head prints onto the medium region corresponding to that image region is adjusted, thereby ensuring uniform spacing between two printed points and guaranteeing printing resolution.

[0112] For example, the spacing between two adjacent nozzles in the printhead along the second direction is less than or equal to a distance threshold. It should be noted that a spacing between two adjacent nozzles less than or equal to the distance threshold can be considered as a very small interval between them. Therefore, even if the printing surface is curved along the second direction, the spacing difference of the printed dots along the second direction can be guaranteed to be very small, and the curvature has little effect on the printed dots, ensuring printing accuracy.

[0113] In this embodiment, the number of pixels in the second printed image is matched with the curvature of the first curved medium. By dividing the first curved medium into partitions according to the curvature and adjusting the resolution of the printed image corresponding to the moving direction, the printing frequency corresponding to different curvatures is different, so that the spacing of ink dots on the curved surfaces with different curvatures is close, thus ensuring printing quality.

[0114] In this embodiment, the first printed image is divided into multiple image regions based on curvature information, and the adjustment ratio corresponding to each image region is determined based on the height change information of the printing surface corresponding to each image region. This means that the printing frequency of the nozzles corresponding to the medium regions with different curvatures is different, so that the spacing between the printing points in the printing surfaces with different curvatures is uniform, thus ensuring the printing resolution.

[0115] Please refer to Figure 11 The illustration shows a schematic flowchart of a first printing image acquisition process provided in an embodiment of this application. The printing system may also include an image acquisition device.

[0116] like Figure 11 As shown, before adjusting the number of pixels in the first printed image according to the curvature information to obtain the second printed image, the surface printing method may further include steps 1102 to 1106.

[0117] Step 1102: The first curved medium, which has been moved to the acquisition position, is image acquired by the image acquisition device to obtain the first image.

[0118] It should be noted that the acquisition position may refer to the position within the field of view of the image acquisition device. When the transfer device transmits the first curved medium to the acquisition position corresponding to the image acquisition device, the image acquisition device can acquire a first image containing at least a portion of the first curved medium.

[0119] For example, the printing system may include one or more image acquisition devices, the sum of the fields of view of each image acquisition device along the second direction covering the first curved medium along the second direction, which can prevent the omission of a portion of the first curved medium due to insufficient field of view. Here, the second direction may refer to a direction perpendicular to the direction of movement of the transfer device.

[0120] In some embodiments, the image acquisition device may include a line scan camera, and a transfer device carrying a first curved medium moves along a first direction. The line scan camera acquires images of the first curved medium by scanning line by line. As the first curved medium moves, the line scan camera captures a series of linear images, which are then stitched together to form a first image containing the complete first curved medium. It should be noted that the scanning speed of the line scan camera and the moving speed of the transfer device are matched to ensure the accuracy and proportional consistency of the stitched first image, and to guarantee the accuracy of the deviation pose information obtained based on the analysis of the first image.

[0121] In some embodiments, the controller acquires the vacuum value corresponding to the adsorption fixture. When the vacuum value is greater than or equal to the adsorption threshold, it triggers the transfer device to move, so that the first curved medium is sequentially transferred to the acquisition position corresponding to the image acquisition device and to the first station corresponding to the printing device. It should be noted that the adsorption threshold can be used to measure whether the adsorption force between the first curved medium and the adsorption fixture is sufficient to make the first curved medium stably positioned on the adsorption fixture. If the vacuum value is greater than or equal to the adsorption threshold, it can be considered that the first curved medium can be stably positioned on the adsorption fixture, that is, the first curved medium will not change its position due to the movement of the transfer device or other reasons. If the vacuum value is less than the adsorption threshold, it can be considered that the first curved medium cannot be stably positioned on the adsorption fixture.

[0122] In this embodiment, the controller can trigger the transfer device to move only when it determines that the vacuum value corresponding to the adsorption fixture is greater than or equal to the adsorption threshold. This ensures that the pose of the first curved medium relative to the adsorption fixture at the collection position is consistent with its pose relative to the adsorption fixture at the first working position, thereby ensuring the printing accuracy of printing the first curved medium based on the transformed first print image.

[0123] For example, the height acquisition device and the image acquisition device respectively scan the first curved surface medium that has been moved to the acquisition position, so that the height information obtained by the height acquisition device can be matched with the first image acquired by the image acquisition device, thereby obtaining the three-dimensional information corresponding to the printing surface of the first curved surface medium.

[0124] Step 1104: Based on the first image, determine the deviation pose information of the first curved medium from the target pose.

[0125] It should be noted that when the pose of the printing medium is the target pose, the printing medium is printed using a reference printing image matched to the target pose, and the printed pattern on the printing medium meets the printing requirements. These printing requirements include that the printed pattern on the printing medium is in the correct position, of the correct size, and without any omissions. In this embodiment, the controller determines the deviation pose information of the first curved medium from the target pose based on the first image, and transforms the reference printing image matched to the target pose based on this deviation pose information to obtain a first printing image that matches the pose of the first curved medium. This ensures that printing on the first curved medium based on the first printing image allows the pattern printed on the first curved medium to also meet the printing requirements.

[0126] In some embodiments, before acquiring an image of the first curved medium moved to the acquisition position using an image acquisition device to obtain a first image, the controller acquires an image of the second printing medium moved to the acquisition position using the image acquisition device to obtain a second image. The pose of the second printing medium is the target pose. A third printing image is then acquired. Based on the third printing image, one or more nozzles of the printing device are controlled to print on the second printing medium moved to the first station. It is determined whether the pattern printed on the second printing medium meets the printing requirements. If not, the image parameters of the third printing image are adjusted. Based on the adjusted third printing image, one or more nozzles of the printing device are controlled to print on the second printing medium moved to the first station until it is determined that the pattern printed on the second printing medium meets the printing requirements. The current third printing image is then determined as the reference printing image. It should be noted that the second printing medium and the first curved medium are of the same type of product, and the two printing media have similar shapes. Image parameters may include, but are not limited to, the size, resolution, and pose of the printed pattern. By adjusting the image parameters of the third printed image, the printing nozzle and / or the printing time of the nozzle (i.e., the time of ink droplet ejection) can be adjusted, thereby changing the size and position of the pattern printed in the second printed image, thus obtaining a second printed medium that meets the printing requirements.

[0127] In some embodiments, based on the first image, a first pose corresponding to the first curved medium is determined, and deviation pose data between the first pose and the target pose is determined. It should be noted that the first pose may include the poses corresponding to one or more points on the printed surface of the first curved medium, and the first pose corresponding to the first curved medium includes position data and angle data of the first curved medium in the first image. The position data may be the coordinates of one or more points on the printed surface in the image coordinate system, and the angle data may include the direction of the line connecting the origin of the image coordinate system and one or more points on the printed surface, and the angle formed with the first axis direction, which may be any axis direction in the image coordinate system. Figure 12 As shown, the first axis direction is the X-axis direction. The direction of the line is θ, the angle data corresponding to point A is θ, and the coordinate data of point A is (x1, y1).

[0128] Step 1106: Obtain a reference printed image that matches the target pose.

[0129] Step 1108: Based on the deviation pose information, transform the reference printed image to obtain the first printed image matching the first curved surface medium.

[0130] It should be noted that when printing a product with the target pose based on the reference print image, a printed medium meeting the printing requirements can be obtained. The controller can store the reference print image, or the reference print image can be stored in a terminal device, and the controller connects to the terminal device to obtain the reference print image. Transformation processing may include, but is not limited to, translation, rotation, and scaling transformations. Translation refers to moving the position of pixels in the reference print image, which can be achieved by adding a fixed offset to the coordinates of the pixels in the reference print image. Rotation refers to rotating the reference print image by a certain angle around its center or a specified point. Scaling refers to changing the size of the reference print image, including enlarging and reducing it.

[0131] For example, based on the deviation pose information, the reference printed image that matches the target pose is transformed to obtain the first printed image that matches the first pose of the first curved medium.

[0132] In related technologies, when the printing medium is not placed at the reference position of the transfer device, the mechanical position of the print head or the transfer device is adjusted to bring the printing medium back to the reference position. In this embodiment, by transforming the reference printed image to match the adjusted first printed image with the first curved surface medium, the printing system can adapt to printing media with different poses and achieve accurate printing on printing media with different poses. At the same time, the transformation processing of the reference printed image matching the target pose is completed by software, which has an extremely fast response speed. Compared with mechanical adjustment, the adjustment speed is faster and avoids mechanical wear.

[0133] In this embodiment, the controller acquires an image of the first curved medium that has moved to the acquisition position using an image acquisition device, obtaining a first image. Based on this first image, the controller determines the deviation pose information of the first curved medium from the target pose, acquires a reference printed image matching the target pose, and transforms the reference printed image based on the deviation pose information to obtain a first printed image matching the first printed image. The controller can first determine the deviation pose information between the first curved medium and the target pose, and then transform the reference printed image matching the target pose based on the deviation pose information, so that the reference printed image undergoes corresponding pose adjustment to obtain a first printed image matching the first curved medium. This ensures that even if the first curved medium changes its pose relative to the target, the pattern printed on the first curved medium can still be aligned, achieving precise printing.

[0134] Meanwhile, the transformation processing of the reference printed image for target pose matching is completed by software, which has an extremely fast response speed. Compared with mechanical adjustment, the adjustment speed is faster and avoids mechanical wear.

[0135] Please refer to Figure 13 The illustration shows a schematic flowchart of a pose deviation information determination process provided in an embodiment of this application, wherein the first curved surface medium is provided with one or more markers.

[0136] like Figure 13 As shown, determining the deviation pose information of the first curved medium from the target pose based on the first image may include steps 1302 to 1306. In this embodiment, the deviation pose information may include the deviation pose data between the first pose corresponding to the first curved medium and the target pose.

[0137] Step 1302: Identify each marker in the first image and determine the image position of each marker in the first image.

[0138] It should be noted that a marker may refer to a portion of the first curved surface medium that has a specific shape, color, pattern, texture, or other significant features. By setting one or more markers on the first curved surface medium, when the first curved surface medium is imaged by an image acquisition device, a first image containing the markers can be acquired. The controller identifies each marker in the first image and determines the image position of each marker in the first image.

[0139] In some embodiments, the controller may store target features corresponding to markers on the first curved medium. Based on these target features, the controller can determine the markers in the first image that match the target features and determine the image position of the markers in the first image. In this embodiment, by pre-storing the target features of each marker, markers matching the target features can be quickly and accurately filtered out, improving the speed of determining pose deviation information. This allows the deviation pose information to be determined before the first curved medium moves to the first workstation, enabling the transformation processing of the reference printed image to obtain the first printed image and ensuring the printing rate.

[0140] In other embodiments, the first image is input into a trained recognition model, which identifies various markers in the first image to obtain the image position of the marker in the first image, as output by the recognition model. It should be noted that the trained recognition model is obtained by training a training sample set, which may include multiple sample images containing markers and the image positions of the markers in each sample image. By training the recognition model using the training sample set, the trained recognition model can identify markers in the first image and locate their image positions within the first image.

[0141] For example, a sample image is input into the recognition model to be trained for recognition, and the location of the marker output by the recognition model is obtained. Based on the location of the marker and the image location corresponding to the sample image, it is determined whether the recognition model to be trained meets the conditions for training completion. If not, the model parameters of the recognition model to be trained are adjusted, and the step of inputting the sample image into the recognition model to be trained for recognition is continued until the recognition model to be trained meets the conditions for training completion, and the trained recognition model is obtained.

[0142] In this embodiment, the markers in the first image are directly identified and located by the recognition model, thereby efficiently and accurately determining the position of the markers in the first image.

[0143] In some embodiments, when the controller detects that the transfer device has moved to the acquisition position, it triggers the image acquisition device to acquire images. If the position of the transfer device is different when the image acquisition device starts acquiring images, even if the pose of the printing medium relative to the transfer device remains unchanged, the position of the printing medium in the first image acquired by the image acquisition device will be different. In this embodiment, triggering the image acquisition device to acquire images when the controller determines that the transfer device has moved to the acquisition position ensures that the position of the transfer device is the same each time image acquisition begins, ensuring the accuracy of the first pose determined based on the first image, and thus ensuring the accuracy of transforming the reference printed image based on the pose deviation information.

[0144] Step 1304: Determine the first pose corresponding to the first curved medium based on the image position corresponding to each marker.

[0145] It should be noted that the first pose may include pose data corresponding to one or more points on the printing surface of the first curved medium. The first pose corresponding to the first curved medium includes the position data and angle data of the first curved medium in the first image.

[0146] In some embodiments, the first curved surface medium is provided with a first marker and a second marker, and the first pose includes first position data and first angle data corresponding to the midpoint between the first marker and the second marker. Determining the first pose corresponding to the first curved surface medium based on the image positions corresponding to each marker may include: the controller determining the first position data and first angle data of the midpoint between the first marker and the second marker in the first image according to the image positions corresponding to the first marker and the second marker.

[0147] For example, if the image position corresponding to the first marker is (x2, y2) and the image position corresponding to the second marker is (x3, y3), then the first position data of the midpoint between the first marker and the second marker in the first image is: The first angle data of the midpoint in the first image is

[0148] Step 1306: Determine the deviation pose data between the first pose and the target pose.

[0149] It should be noted that the deviation pose data is used to characterize the deviation between the first pose and the target pose, and the deviation pose data may include deviation position data and / or deviation angle data.

[0150] In some embodiments, the first pose includes first position data and first angle data corresponding to the midpoint between the first marker and the second marker, and the target pose includes target position data and target angle data. Determining the deviation pose data between the first pose and the target pose may include: determining the deviation position data between the first position data and the target position data, and determining the deviation angle data between the first angle data and the target angle data.

[0151] It should be noted that the controller can pre-store target position data and target angle data. When the first position data and first angle data corresponding to the midpoint between the first and second markers are determined based on the image positions corresponding to each marker, the difference between the first position data and the target position data can be calculated. This difference can be used as deviation position data. The difference between the first angle data and the target angle data can be determined. This difference can be used as deviation angle data.

[0152] In some embodiments, the second printing medium includes a first marker and a second marker. The controller can determine the target position data and target angle data of the midpoint between the first and second markers in the second image based on the image positions of the first and second markers in the second image. It should be noted that the first marker of the second printing medium matches the first marker of the first printing medium, and the second marker of the second printing medium matches the second marker of the first printing medium. During the manufacturing of each printing medium, corresponding first and second markers can be formed on the printing medium to achieve positioning. In this embodiment, by storing the target position data and target angle data of the midpoint between the first and second markers in the second image, the deviation pose data between the first pose and the target pose can be determined when the first position data and the first angle data are obtained, reducing the storage and computational load of the controller.

[0153] In some embodiments, transforming a reference printed image that matches a target pose based on deviation pose information to obtain a first printed image that matches the first pose may include: the controller performing a translation operation on the reference printed image based on deviation position data and a rotation operation on the reference printed image based on deviation angle data to obtain the first printed image.

[0154] In this embodiment, a first printed image is obtained by translating the reference printed image according to the deviation position data and rotating the reference printed image according to the deviation angle data. The pose of the pattern in the first printed image matches the pose of the first printed medium. Based on the first printed image, one or more nozzles of the coating device are controlled to print the first printed medium that has moved to the first station. This ensures that the position of the pattern printed on the first printed medium is consistent with the position of the pattern obtained by printing the second printed medium that has moved to the first station based on the reference printed image. This ensures that the printing accuracy of the first printed medium is maintained even if the pose of the first printed medium deviates from that of the second printed medium.

[0155] In this embodiment, by identifying each marker in the first image, the image position of each marker in the first image is determined, and based on each image position, the first pose corresponding to the first curved medium is determined, thereby determining the deviation pose data between the first pose and the target pose. This ensures the accuracy of the determined deviation pose data and guarantees the printing accuracy based on the first printing image.

[0156] Please refer to Figure 14 This illustrates a flowchart of another pose deviation information determination process provided in an embodiment of this application. Figure 14 As shown, determining the deviation pose information of the first curved medium from the target pose based on the first image may include steps 1402 to 1406.

[0157] Step 1402: Perform image matching between the first image and the second image corresponding to the target pose to obtain multiple sets of feature point pairs.

[0158] Each feature point pair includes a first feature point in a first image and a second feature point in a second image that matches the first feature point. The second image is acquired by an image acquisition device.

[0159] In some embodiments, image matching is performed between the first image and the second image corresponding to the target pose to obtain multiple sets of feature point pairs. This may include: the controller extracting first feature points from the first image and second feature points from the second image, and performing feature point matching on multiple first feature points and multiple second feature points to obtain multiple sets of feature points. Feature points may include keypoints and descriptors. A keypoint refers to the image position of the feature point in the image, and a descriptor is typically a vector describing information about the pixels surrounding the keypoint. Feature point matching is performed on feature descriptors. The distance between two descriptors reflects the similarity between the two feature points, i.e., whether the two feature points are the same. Different distance metrics can be selected depending on the descriptor. For floating-point descriptors, Euclidean distance can be used; for BRIEF (Binary Robust Indenpendent Elementary Features) descriptors, Hamming distance can be used (the Hamming distance between two different binary strings refers to the number of different bits in the two binary strings).

[0160] In some embodiments, the controller may extract a first feature point in the first image and a second feature point in the second image based on the SIFT algorithm, or the controller may extract the first feature point in the first image and the second feature point in the second image based on the KAZE algorithm. SIFT (Scale-invariant feature transform) is a machine vision algorithm used to detect and describe local features in images. It finds extreme points in spatial scale and extracts their position, scale, and rotation invariants. KAZE (KAZE Accelerated Segment Test) is a feature detection method based on nonlinear scale space, exhibiting good scale invariance and robustness. Understandably, the controller may also extract the first feature point in the first image and the second feature point in the second image based on other algorithms; this embodiment does not limit this approach.

[0161] Step 1404: Based on multiple sets of feature point pairs, determine the deviation distance between the first feature point and the second feature point in each set of feature point pairs.

[0162] It should be noted that the deviation distance refers to the distance between the image position of the first feature point in the first image and the image position of the second feature point in the second image. For example, the coordinates of the first feature point in the first image are (x4, y4), and the coordinates of the second feature point in the second image are (x5, y5). The deviation distance for this feature point pair includes a first displacement Δx in the first direction and a second displacement Δy in the second direction, where Δx = x4 - x5 and Δy = y4 - y5.

[0163] Step 1406: Determine the deviation pose information of the first curved surface medium from the target pose based on the deviation distances corresponding to multiple sets of feature point pairs.

[0164] It should be noted that the deviation pose information of the first curved medium from the target pose may include the deviation pose data between the first pose corresponding to the first curved medium and the target pose.

[0165] In some embodiments, the controller can determine a third displacement of the first image relative to the second image in a first direction and a fourth displacement of the first image relative to the second image in a second direction based on the first displacement and second displacement corresponding to multiple sets of feature point pairs, respectively. It should be noted that multiple first feature points are uniformly distributed in the first image, and multiple second feature points are uniformly distributed in the second image. Based on the third displacement of the first image and the second image in the first direction, and the fourth displacement of the first image and the second image in the second direction, a transformation process is performed on the reference printed image. The overall translational and rotational deviations of the reference printed image are adjusted to ensure the printing accuracy based on the transformed first printed image.

[0166] Optionally, determining the third displacement of the first image relative to the second image in the first direction and the fourth displacement of the first image relative to the second image in the second direction based on the first displacement and the second displacement corresponding to the multiple sets of feature point pairs respectively may include: calculating the average of the first displacement corresponding to the multiple sets of feature point pairs to obtain the third displacement, and calculating the average of the second displacement corresponding to the multiple sets of feature point pairs to obtain the fourth displacement.

[0167] In this embodiment, based on the deviation distances corresponding to multiple feature point pairs in the first image and the second image, the deviation pose information of the first curved medium from the target pose is determined, and the reference printed image matching the target pose is transformed based on the deviation pose information to obtain the first printed image matching the first curved medium, thus ensuring the accuracy of the obtained first printed image.

[0168] Please refer to Figure 15This diagram illustrates a structural schematic of a curved surface printing apparatus according to an embodiment of this application. The apparatus can be applied to the controller of a printing system. The printing system also includes a height acquisition device, a transfer device, and a printing device. The transfer device carries a first curved surface medium and first transfers the first curved surface medium to the acquisition position corresponding to the height acquisition device, and then transfers the first curved surface medium to the first station corresponding to the printing device. The printing surface of the first curved surface medium includes a curved surface. Figure 15 As shown, the curved surface printing apparatus 1500 may include a height acquisition module 1510, a curvature determination module 1520, an image adjustment module 1530, and a printing control module 1540. The height acquisition module 1510 acquires the height of a first curved surface medium that has moved to the acquisition position using a height acquisition device, obtaining height information corresponding to the printing surface of the first curved surface medium. The curvature determination module 1520 determines the curvature information of the printing surface of the first curved surface medium based on the height information. The image adjustment module 1530 adjusts the number of pixels in the first printed image based on the curvature information to obtain a second printed image. The printing control module 1540 controls one or more nozzles of the printing apparatus to print the first curved surface medium that has moved to the first station based on the second printed image.

[0169] In some embodiments, the image adjustment module 1530 includes a division unit, a first determination unit, and an adjustment unit. The division unit is used to divide the first printed image into multiple image regions based on curvature information. The first determination unit is used to determine the adjustment ratio corresponding to each image region based on the height change information corresponding to the printing surface of each image region. The adjustment unit is used to adjust the number of pixels contained in each image region according to the adjustment ratio corresponding to each image region to obtain a second printed image.

[0170] In some embodiments, the height information includes height data corresponding to multiple points on the printed surface, height change information corresponding to the printed surface of the image region, including the slope of the printed surface corresponding to the image region. The curved surface printing apparatus 1500 may further include a first determining module and a second determining module. The first determining module is used to determine the highest point and the lowest point of the printed surface corresponding to the first image region; wherein the highest point is the point with the largest height data in the printed surface corresponding to the first image region, and the lowest point is the point with the smallest height data in the printed surface corresponding to the first image region; the first image region is any one of multiple image regions. The second determining module is used to determine the slope of the printed surface corresponding to the first image region based on the image position of the highest point in the first image region, the height data of the highest point, the image position of the lowest point in the first image region, and the height data of the lowest point.

[0171] In some embodiments, the transfer device carries a first curved medium and moves it at a constant speed along a first direction. The adjustment unit is further configured to perform interpolation processing on each image region in the first printed image along the first direction according to the adjustment ratio corresponding to each image region to obtain a second printed image; wherein, the ratio between the number of pixels in each image region in the second printed image along the first direction and the number of pixels in the corresponding image region in the first printed image along the first direction is the adjustment ratio corresponding to the corresponding image region.

[0172] In some embodiments, the printing system further includes an image acquisition device, and the curved surface printing device 1500 may further include an image acquisition module, a third determination module, an acquisition module, and an image transformation module. The image acquisition module is used to acquire an image of the first curved surface medium moved to the acquisition position using the image acquisition device, thereby obtaining a first image. The third determination module is used to determine, based on the first image, the deviation pose information of the first curved surface medium from the target pose. The acquisition module is used to acquire a reference printed image matching the target pose. The image transformation module is used to transform the reference printed image based on the deviation pose information to obtain a first printed image matching the first curved surface medium.

[0173] In some embodiments, the first curved surface medium is provided with one or more markers, and the third determining module includes an identification unit, a second determining unit, and a third determining unit. The identification unit is used to identify each marker in the first image and determine the image position of each marker in the first image. The second determining unit is used to determine a first pose corresponding to the first curved surface medium based on the image position corresponding to each marker. The third determining unit is used to determine the deviation pose information between the first pose and the target pose.

[0174] In some embodiments, the first curved surface medium is provided with a first marker and a second marker. The first pose includes first position information and first angle information corresponding to the midpoint between the first marker and the second marker, and the target pose includes target position information and target angle information corresponding to the midpoint. The third determining unit is further configured to determine the deviation position information between the first position information and the target position information, and to determine the deviation angle information between the first angle information and the target angle information.

[0175] In this embodiment, the controller acquires the height of the first curved medium that has moved to the acquisition position using a height acquisition device, obtaining the height information corresponding to the printing surface of the first curved medium. Based on the height information, the controller determines the curvature information of the printing surface of the first curved medium. The controller then adjusts the number of pixels in the first printed image based on the curvature information to obtain a second printed image. Based on the second printed image, the controller controls one or more nozzles of the printing device to print on the first curved medium that has moved to the first station. The controller adjusts the number of pixels in the first printed image based on the curvature information to obtain the second printed image, ensuring that the printing frequency (frequency of ink droplet ejection) of the nozzles matches the curvature information. This guarantees that the distribution of printed dots in the printed pattern on the first curved medium is uniform based on the second printed image, i.e., the resolution is similar, thus ensuring print quality.

[0176] This application also provides a printing system, which may include a height acquisition device, a printing device, a transfer device, and a controller. The transfer device carries a first printing medium and first transfers the first printing medium to the acquisition position corresponding to the height acquisition device, and then transfers the first printing medium to the first workstation corresponding to the printing device.

[0177] Please refer to Figure 16 This illustrates a schematic diagram of the controller structure of a printing system disclosed in an embodiment of this application. Figure 16 As shown, the controller 1600 may include:

[0178] Memory 1610 storing executable program code;

[0179] Processor 1620 coupled to memory 1610;

[0180] The processor 1620 calls the executable program code stored in the memory 1610 to execute any of the surface printing methods disclosed in the embodiments of this application.

[0181] This application discloses a computer-readable storage medium storing a computer program, wherein when the computer program is executed by the processor, the processor implements any of the surface printing methods disclosed in this application.

[0182] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Those skilled in the art should also recognize that the embodiments described in the specification are optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0183] In the various embodiments of this application, it should be understood that the sequence number of each process does not necessarily imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0184] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they can be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0185] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0186] If the aforementioned integrated units are implemented as software functional units and sold or used as independent products, they can be stored in a computer-accessible memory. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several requests to cause a computer device (which can be a personal computer, server, or network device, specifically a processor in the computer device) to execute some or all of the steps of the methods described in the various embodiments of this application.

[0187] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, including read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-Erasable Programmable Read-Only Memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, disk storage, magnetic tape storage, or any other computer-readable medium capable of carrying or storing data.

[0188] The foregoing has provided a detailed description of a curved surface printing method, apparatus, printing system, and computer-readable storage medium disclosed in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and its core ideas. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for printing curved surfaces, characterized in that, A controller for a printing system, the printing system further comprising a height acquisition device, a transfer device, and a printing device, wherein the transfer device carries a first curved surface medium and first transfers the first curved surface medium to the acquisition position corresponding to the height acquisition device, and then transfers the first curved surface medium to the first station corresponding to the printing device, the printing surface of the first curved surface medium comprising a curved surface; the method includes: The height of the first curved medium that has moved to the acquisition position is acquired by the height acquisition device, and the height information corresponding to the printing surface of the first curved medium is obtained. Based on the height information, the curvature information of the printing surface of the first curved medium is determined; Based on the curvature information, the first printed image is divided into multiple image regions; Based on the height change information of the printed surface corresponding to each of the image regions, determine the adjustment ratio corresponding to each of the image regions; The number of pixels contained in each of the image regions is adjusted according to the adjustment ratio corresponding to each of the image regions to obtain the second printed image; Based on the second printed image, control one or more nozzles of the printing device to print the first curved medium that has moved to the first station; The height information includes height data corresponding to multiple points on the printed surface, and the height change information of the printed surface corresponding to the image region includes the slope of the printed surface corresponding to the image region; the method further includes: Determine the highest and lowest points of the printed surface corresponding to the first image region; wherein, the highest point is the point with the largest height data in the printed surface corresponding to the first image region, and the lowest point is the point with the smallest height data in the printed surface corresponding to the first image region; the first image region is any one of the plurality of image regions; Based on the image position of the highest point in the first image area, the height data of the highest point, the image position of the lowest point in the first image area, and the height data of the lowest point, the slope of the printed surface corresponding to the first image area is determined.

2. The method according to claim 1, characterized in that, The transfer device carries the first curved medium and moves it at a constant speed along a first direction; the step of adjusting the number of pixels contained in each of the image regions according to the adjustment ratio corresponding to each of the image regions to obtain the second printed image includes: According to the adjustment ratio corresponding to each of the image regions, interpolation processing is performed on each of the image regions in the first printed image along the first direction to obtain a second printed image; wherein, the ratio between the number of pixels in each of the image regions in the second printed image along the first direction and the number of pixels in the corresponding image region in the first printed image along the first direction is the adjustment ratio corresponding to the corresponding image region.

3. The method according to claim 1, characterized in that, The printing system further includes an image acquisition device; the method further includes: The image acquisition device acquires an image of the first curved medium that has moved to the acquisition position, thereby obtaining a first image. Based on the first image, determine the deviation pose information of the first curved medium from the target pose; Obtain a reference printed image that matches the target pose; Based on the deviation pose information, the reference printed image is transformed to obtain a first printed image that matches the first curved surface medium.

4. The method according to claim 3, characterized in that, The first curved surface medium is provided with one or more markers; the step of determining the deviation pose information of the first curved surface medium from the target pose based on the first image includes: Identify each marker in the first image and determine the image position of each marker in the first image; Based on the image positions corresponding to each of the markers, the first pose corresponding to the first curved medium is determined. Determine the deviation pose information between the first pose and the target pose.

5. The method according to claim 4, characterized in that, The first curved surface medium is provided with a first marker and a second marker. The first pose includes first position information and first angle information corresponding to the midpoint between the first marker and the second marker. The target pose includes target position information and target angle information corresponding to the midpoint. Determining the deviation pose information between the first pose and the target pose includes: Determine the deviation position information between the first position information and the target position information; Determine the deviation angle information between the first angle information and the target angle information.

6. A curved surface printing device, characterized in that, A controller for a printing system, the printing system further comprising a height acquisition device, a transfer device, and a printing device, wherein the transfer device carries a first curved surface medium and first transfers the first curved surface medium to the acquisition position corresponding to the height acquisition device, and then transfers the first curved surface medium to the first station corresponding to the printing device, the printing surface of the first curved surface medium being curved; the curved surface printing device includes: The height acquisition module is used to acquire the height of the first curved medium that has moved to the acquisition position through the height acquisition device, and obtain the height information corresponding to the printing surface of the first curved medium; The curvature determination module is used to determine the curvature information of the printing surface of the first curved medium based on the height information; The image adjustment module includes a division unit, a first determining unit, and an adjustment unit. The division unit divides a first printed image into multiple image regions based on the curvature information. The first determining unit determines an adjustment ratio for each image region based on the height change information of the printing surface corresponding to each image region. The adjustment unit adjusts the number of pixels in each image region according to the adjustment ratio, thereby obtaining a second printed image. The printing control module is used to control one or more nozzles of the printing device to print the first curved medium that has moved to the first station, based on the second printed image. The height information includes the height data corresponding to multiple points in the printed surface, and the height change information of the printed surface corresponding to the image area includes the slope of the printed surface corresponding to the image area. The curved surface printing device also includes: A first determining module is used to determine the highest and lowest points of the printed surface corresponding to the first image region; wherein the highest point is the point with the largest height data in the printed surface corresponding to the first image region, and the lowest point is the point with the smallest height data in the printed surface corresponding to the first image region; the first image region is any one of the plurality of image regions; and The second determining module is used to determine the slope of the printed surface corresponding to the first image area based on the image position of the highest point in the first image area, the height data corresponding to the highest point, the image position of the lowest point in the first image area, and the height data corresponding to the lowest point.

7. A printing system, characterized in that, include: Altitude acquisition device; Printing device; A transfer device is used to carry a first curved surface medium and first transfer the first curved surface medium to the acquisition position corresponding to the height acquisition device, and then transfer the first curved surface medium to the first station corresponding to the printing device, wherein the printing surface of the first curved surface medium includes a curved surface; and A controller includes a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the method as described in any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 5.

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