Paperless drawing method and paperless drawing device

Abstract

The invention discloses a paperless drawing method and a paperless drawing device. The device comprises a main control module, a touch display module, a projection module, a keyboard module and an electronic drawing module, the touch display module and the keyboard module are used for acquiring instructions input by a user, including establishment of a drawing task and selection of a drawing template and scale parameters; the main control module is used for correcting the projection module and the electronic drawing module; according to an instruction input by a user, a graph needing to be projected is sent to the projection module for projection display, an electronic drawing drawn by the electronic drawing module is received and stored, and interaction between the projection module and the electronic drawing module is achieved; according to the application, convenient and flexible integrated design is adopted: the equipment adopts an integrated structure and is exquisite and integrated, paperless operation is realized, and standard drawings can be put in an accurate proportion of 1: 1.

Description

Technical Field

[0001] The present invention relates to the technical field of paperless drawing, and in particular to a paperless drawing method and a paperless drawing device. Background Art

[0002] In highly specialized fields such as engineering drawing and trajectory calculation, traditional drawing methods have many drawbacks. From a resource consumption perspective, each drawing or calculation operation requires a large amount of paper, which not only wastes resources but also puts continuous pressure on the ecological environment. In terms of drawing management, storage requires a specific space, and due to the characteristics of paper carriers, they are easily damaged by environmental factors. At the same time, there is a lack of efficient indexing mechanism, and the slightest carelessness in organizing can easily lead to loss. When searching, manual retrieval from massive paper files is required, which is a lengthy and inefficient process. When modifying a drawing, it is often necessary to redraw the entire drawing, which seriously restricts work progress.

[0003] With the rise and development of digital technology, electronic drawing tools have emerged. However, these existing electronic drawing tools are not suitable for engineering drawing and trajectory calculation, and have the following shortcomings: 1. In terms of user experience, the interface is complex, with numerous buttons and settings that require users to spend a lot of time learning and adapting. Even experienced users need to frequently switch functions when performing complex drawing operations, which affects drawing efficiency. 2. Accurate point calculation is crucial in engineering drawing and trajectory calculation. Existing electronic drawing tools lack a standard drawing reference system. Draftsmen can only rely on experience and estimation when calculating points, making it difficult to achieve accurate calculations. 3. During the local drawing or calculation process, there is a lack of an effective association mechanism, making it difficult for draftsmen to easily compare local content with the overall drawing. This makes it difficult to control the layout and proportional relationship of the drawing as a whole during the drawing process, affecting the quality of the final drawing results. 4. Most current electronic drawing tools use a split design, with the drawing board and computer existing independently and connected via cables. This, to a certain extent, limits the placement and usage of the equipment. Draftspeople cannot freely move the drawing board to the appropriate position during operation. 5. There are also existing technologies that use projectors for drawing, but they can only draw two-dimensional drawings and cannot draw three-dimensional drawings. Summary of the Invention

[0004] Therefore, the purpose of the present invention is to provide a paperless drawing method and a paperless drawing device, which adopt the interactive use of projection and drawing board to enable draftsmen to accurately draw in a paperless environment, store the drawing process, and form an electronic file.

[0005] In order to achieve the above object, the present invention provides a paperless drawing method comprising the following steps: S1. Create a drawing task, select a drawing template and the first scale parameter; S2. Perform the first synchronous calibration of the projection drawing and the drawing board under the currently selected first scale parameter; S3. Draw a graphic on the projection drawing, and collect contact signals activated by the drawing board in the drawing process in sequence to form an electronically drawn graphic; S4. Save the electronic drawing generated under the first scale parameters; S5. Obtain the target location point and the second scale parameter selected by the user in the current electronic drawing; S6. Under the currently selected second scale parameter, the projection drawing and the drawing board are synchronized and calibrated again; S7, enlarging the target area of the projection drawing according to the target location point and the second scale parameter selected by the user; S8. For the enlarged projection drawing, draw the electronic drawing under the second scale parameter according to the process of S3 above; S9. Complete the drawing of the corresponding electronic image under each scale parameter according to the above process, and store it in partitions with the coordinates of the target position point as the index until the overall drawing of the electronic drawing is completed.

[0006] Furthermore, preferably, the drawing template includes a two-dimensional drawing template and a three-dimensional drawing template.

[0007] Further, preferably, in S2, the first synchronous calibration of the projection drawing and the drawing board includes: establishing a coordinate mapping model between the projection device and the drawing board based on the installation position relationship between the two, specifically including: The internal and external parameters of the projection equipment are obtained by using the calibration method; Through internal and external parameters, the projection matrix between the image coordinate system of the projection module and the physical coordinate system of the drawing board is established; A multi-point calibration method is used for optimization to solve the projection matrix and obtain an optimized projection matrix; Using the optimized projection matrix, the corrected image is output.

[0008] Furthermore, preferably, the projection matrix between the projection module image coordinate system and the drawing board physical coordinate system established by the internal and external parameters is expressed by the following formula: (1) Among them, s is the scale factor, u and v are the projected image coordinates, X and Y are the coordinates of the two-dimensional coordinate system with the drawing board as the plane, H is the projection transformation matrix, R is the rotation matrix, t is the translation vector, and K is the intrinsic parameter matrix.

[0009] Furthermore, preferably, when the drawing template selects a three-dimensional drawing template, the method further includes: Create a first electronic drawing under the current view plane according to the first view plane selected by the user; Extracting vertex coordinates from the first electronic drawing, and when the user selects a second viewing plane, projecting the vertices from the first electronic drawing onto a second electronic drawing to be drawn corresponding to the second viewing plane based on a correspondence between the first viewing plane and the second viewing plane, thereby completing details in the second electronic drawing; And so on, complete the drawing of electronic drawings corresponding to all view planes; The common axes and common vertices in the electronic drawings corresponding to each view plane are extracted and merged to form a three-dimensional electronic drawing.

[0010] Furthermore, preferably, the method further includes using a binocular recognition camera to collect multi-angle views of the solid three-dimensional model; performing edge extraction according to the collected multi-angle views to obtain edge coordinate data; projecting the edge coordinate data corresponding to each angle view onto an electronic drawing of a view plane corresponding to the angle view, performing modification, and obtaining a three-dimensional view of the solid three-dimensional model.

[0011] The present invention also provides a paperless drawing device for implementing the steps of the above-mentioned paperless drawing method, comprising: a main control module, a touch display module, a projection module, a keyboard module, and an electronic drawing module; The touch display module and keyboard module are used to obtain user input instructions, including establishing a drawing task, selecting a drawing template and scale parameters; The main control module is used to calibrate the projection module and the electronic drawing module. According to the instructions input by the user, the main control module sends the graphics to be projected to the projection module for projection display, receives and saves the electronic drawings drawn by the electronic drawing module, and realizes the interaction between the projection module and the electronic drawing module. The main control module includes: under the currently selected first scale parameter, performing the initial synchronous calibration of the projection drawing and the drawing board; Obtain the drawing graphics on the projection drawing, and sequentially collect the electronic drawing graphics formed by the contact signals activated by the drawing board during the drawing process in the drawing order; saving the electronic drawing generated under the first scale parameters; Get the target location point and the second scale parameter selected by the user in the current electronic drawing; Under the currently selected second scale parameter, the projection drawing and drawing board are synchronized again; According to the target location point and the second scale parameter selected by the user, the target area of the projection drawing is enlarged; For the enlarged projection drawing, draw the electronic drawing under the second scale parameter according to the above process; According to the above process, the drawing of the corresponding electronic image under each scale parameter is completed, and the coordinates of the target position point are used as index partition storage until the overall drawing of the electronic drawing is completed.

[0012] Furthermore, preferably, the electronic drawing module includes an electromagnetic induction drawing board and an electronic stylus; the drawing area of the electromagnetic induction drawing board adopts electromagnetic induction technology, and the drawing area is provided with copper lines arranged evenly horizontally and vertically, cutting the electromagnetic induction board into multiple squares, and generating a balanced criss-cross magnetic field above the board surface; the electronic stylus adopts an EMR passive stylus, and when the tip or tail of the pen is close to the drawing board, the internal resonant circuit resonates with the electromagnetic field generated by the drawing board, and the writing operation or erasing operation is achieved by marking the positive and negative of the resonant signal.

[0013] Furthermore, preferably, the projection module is installed on one side of the electromagnetic induction drawing board through an interface, and the angle θ between the projection module and the electromagnetic induction drawing board is in the range of 45°<θ<90°.

[0014] Furthermore, preferably, a binocular recognition camera is further included, and the binocular recognition camera is used to obtain a depth image of the three-dimensional entity to be drawn.

[0015] The paperless drawing method and paperless drawing device disclosed in this application have at least the following advantages over the prior art: 1. This application adopts a convenient and flexible integrated design, achieving an integrated structure and sophisticated integration, allowing for easy single-handed lifting, greatly improving portability. It also features a built-in high-performance battery, eliminating reliance on external power sources. Whether on a construction site, in an outdoor operation, or in a temporary scenario without power access, it can be operated at any time, providing users with a convenient experience regardless of space restrictions.

[0016] 2. This application utilizes advanced projection technology, enabling paperless operation and capable of projecting standard drawings at a precise 1:1 scale. This feature ensures that the projected content is identical to the paper drawing, with precise rendering of line thickness, graphic dimensions, and annotation placement. This seamless integration of virtual projection and traditional paper drawings significantly improves the accuracy and standardization of drawings.

[0017] 3. When drawing a specific area, the device's display area displays the overall design. While users focus on a specific detail, they can simultaneously see the overall layout, preventing disconnection between the detailed drawing and the overall design. This balanced approach effectively enhances drawing coherence and coordination, significantly improving drawing quality.

[0018] 4. This application is extremely simple to operate, equipped with physical buttons for function operation. Compared with complex touch screen operation and menu settings, physical buttons have clear tactile feedback and functional indications, allowing users to quickly get started without a complicated learning process, reducing the rate of operational errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention provides a paperless drawing method flow chart.

[0020] Figure 2 This is a schematic diagram of a paperless drawing device provided by the present invention.

[0021] Figure 3 This is a comparison chart of the effects of projection correction performed by the present invention.

[0022] In the picture: 01. Display touch screen; 02. Keyboard module; 03. Electronic stylus; 04. Electronic drawing board; 05. Rotating hinge; 06. Projection module. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] This application aims to solve the problem of needing to make simple paper drawings based on actual scenarios in real work. Different from electronic drawing according to design intention and electronic drawing according to the target image taken by aircraft or camera, this application is suitable for real-time recording of the target's position or the target's movement trajectory when it is unclear whether the target will appear in the next moment; and the recorded data is recorded in the form of electronic drawings.

[0025] like Figure 1 As shown, an embodiment of the present invention provides a paperless drawing method, comprising the following steps: S1. Establish a drawing task, select a drawing template and a first scale parameter. Further, preferably, the drawing template includes a two-dimensional drawing template and a three-dimensional drawing template. The first scale parameter can be any value, and is intended to nest subsequently drawn drawings of different scales according to the scale requirements of different parts of the overall drawing.

[0026] S2. Perform the first synchronous calibration of the projection drawing and the drawing board under the currently selected first scale parameter; S3, drawing a figure on the projection drawing, and collecting the contact signals activated by the drawing board in the drawing process in sequence to form an electronic drawing figure; S4. Save the electronic drawing generated under the first scale parameters; S5. Obtain the target location point and the second scale parameter selected by the user in the current electronic drawing; S6. Under the currently selected second scale parameter, the projection drawing and the drawing board are synchronized and calibrated again; S7, enlarging the target area of the projection drawing according to the target location point and the second scale parameter selected by the user; S8. For the enlarged projection drawing, draw the electronic drawing under the second scale parameter according to the process of S3 above; S9. Complete the drawing of the corresponding electronic image under each scale parameter according to the above process, and store it in partitions with the coordinates of the target position point as the index until the overall drawing of the electronic drawing is completed.

[0027] The first scale parameter and the second scale parameter can be adjusted freely, and generally you can choose 1:1, 1:2, 1:4 and 1:8, etc.

[0028] Further, preferably, in S2, the first synchronous calibration of the projection drawing and the drawing board includes: establishing a coordinate mapping model between the projection device and the drawing board based on the installation position relationship between the two, specifically including: The internal and external parameters of the projection equipment are obtained by using the calibration method; Through internal and external parameters, the projection matrix between the image coordinate system of the projection module and the physical coordinate system of the drawing board is established; A multi-point calibration method is used for optimization to solve the projection matrix and obtain an optimized projection matrix; Using the optimized projection matrix, the corrected image is output.

[0029] Since the hand is blocked by the orthographic projection during drawing, the shadow of the hand affects the light result. Therefore, the projection module is not perpendicular to the electronic drawing board, and there is a certain tilt angle between the projection module and the electromagnetic induction drawing board. θ , the selected projection area must be corrected for distortion before it can be projected to the standard size.

[0030] To this end, a coordinate mapping model between the projection device and the drawing board is established through the installation position relationship between the two. Two correction processes can be used: First calibration process: Detecting the tilt angle based on the angle sensor installed at the installation position between the projection device and the drawing board θ; like Figure 3 As shown, Figure 3 The left side is the tilted projection before correction. It can be seen that the projection is an ellipse due to the angle. Figure 3 The right side of is the orthographic projection after correction; therefore, For each point of the oblique projection ( , ) Apply the reverse rotation to get the orthographic projection (x, y); However, this is an ideal conversion relationship based on a single point and when there is no distortion in the intrinsic and extrinsic parameter matrices of the projector camera. If used for the entire projected image, the projected image generally selects a plane figure, such as a circle. When a circle is selected, two mutually perpendicular cross extension lines passing through the center of the circle are set at the center of the circle, and there are multiple intersections between the cross extension lines and the edge of the circle. At least three intersections are selected and marked as P1, P2, and P3; before correction, due to the existence of the tilt angle, the circle will be projected as an ellipse. At this time, click on the marked intersections P1', P2', and P3' in the projected ellipse, and record the coordinates of the three intersections P1', P2', and P3' at this time; the inverse transformation matrix is obtained according to the coordinates of P1', P2', and P3' and the original coordinates of P1, P2, and P3. When the image matrix in the projector is reversely adjusted according to the inverse transformation matrix, the figure formed after re-projection is the figure of the positive projection.

[0031] In the second correction process, based on the plane projection algorithm and the known installation position relationship between the projection module and the electronic drawing board, a coordinate mapping model is established between the two, so as to accurately map the projected image to the drawing board, correct the deformation and fill the complete area, and can accurately give the projection image coordinates corresponding to the click position of the electronic stylus on the drawing board in real time.

[0032] The algorithm principle is based on the perspective projection transformation of the homography matrix. By establishing the homography matrix between the image coordinate system of the projection module and the physical coordinate system of the drawing board, bidirectional coordinate mapping is achieved.

[0033] The internal and external parameters of the projection module can be obtained through calibration: Projection intrinsic parameter matrix: Where f is the focal length of the projection module in the image coordinate system, 、 Respectively represent the coordinates of the projection point of the projection module optical axis in the image coordinate system on the x-axis and y-axis; Projection external parameters: rotation matrix R, translation vector ; in Represents the translation components in the x, y, and z directions in the world coordinate system respectively; The mapping relationship between the projection module and the drawing board plane can be established through internal and external parameters: Furthermore, preferably, the projection matrix between the projection module image coordinate system and the drawing board physical coordinate system established by the internal and external parameters is expressed by the following formula: (1) Among them, s is the scale factor, u and v are the projected image coordinates, X and Y are the coordinates of the two-dimensional coordinate system with the drawing board as the plane, H is the projection transformation matrix, R is the rotation matrix, t is the translation vector, and K is the intrinsic parameter matrix.

[0034] After calculating the projection matrix, the coordinates of the touch point on the drawing board corresponding to the projected image can be reversely calculated according to the following formula: (2) in, 、 The coordinates of the touch point in the drawing board coordinate system.

[0035] During the actual installation process, there are errors caused by manual labor, the mechanical structure itself, and the calibration process. The following method can be used to calibrate and optimize the perspective projection matrix to improve the accuracy of the calculation.

[0036] The multi-point calibration method (at least 4 groups of points) is used to solve the H matrix. According to formula (1), it can be concluded that the mapping relationship of each point conforms to the following formula: (3) in , represents the coordinates of the i-th group of points in the drawing board coordinate system, , Represents the image coordinate system coordinates corresponding to the i-th group of points; Projection matrix H According to formula (3), the projection matrix H can be used to project the points in the drawing board coordinate system to the image coordinate system. The elements that make up the projection matrix H are , respectively representing the rotation, scaling and affine transformation relationship between the two plane coordinate systems, which can be solved by the secondary linear equations of multiple points.

[0037] The optimized projection matrix H can be obtained by calculating the linear equation (4): (4) Finally, the image output by the projection module is projected and mapped onto the drawing board according to the projection matrix.

[0038] Since the first process is the ideal projection coordinate obtained without considering the distortion parameters of the projector, and the projection position (x1, y1) obtained in the second process is the actual projection coordinate after considering the distortion factor, the results obtained in the first and second processes also need to be calculated for the deviation value. The first projection is based on the circular projection O1 displayed after the first correction. Click the center of the projected circle to obtain the center point coordinate O1 at this time; then, according to the circular projection O2 formed by the second correction process, click the center point O2 of the circular projection on the drawing board again. When the deviation value does not exceed the threshold, it proves that the distortion of the camera in the second correction process is within a reasonable range. At this time, the projection image formed after the second correction process can be selected as the final corrected projection.

[0039] Furthermore, preferably, when the drawing template selects a three-dimensional drawing template, the method further includes: Create a first electronic drawing under the current view plane according to the first view plane selected by the user; Extracting vertex coordinates from the first electronic drawing, and when the user selects a second viewing plane, projecting the vertices from the first electronic drawing onto a second electronic drawing to be drawn corresponding to the second viewing plane based on a correspondence between the first viewing plane and the second viewing plane, thereby completing details in the second electronic drawing; And so on, complete the drawing of electronic drawings corresponding to all view planes; The common axes and common vertices in the electronic drawings corresponding to each view plane are extracted and merged to form a three-dimensional electronic drawing.

[0040] Furthermore, preferably, the method further includes using a binocular recognition camera to collect multi-angle views of the solid three-dimensional model; performing edge extraction according to the collected multi-angle views; projecting the extracted edge coordinate data and the edge coordinate data corresponding to each angle view onto an electronic drawing of a view plane corresponding to the angle view, performing modification, and obtaining a three-dimensional view of the solid three-dimensional model.

[0041] like Figure 2The present invention also provides a paperless drawing device for implementing the steps of the above-mentioned paperless drawing method, comprising: a main control module, a touch display module, a projection module, a keyboard module, and an electronic drawing module; the touch display module employs a display touch screen 01, which is connected to an electronic drawing board 04 via a hinge 05. When a user draws on the electronic drawing board 04 using an electronic stylus 03, an electromagnetic signal is transmitted to the main control module below the display touch screen. A plug-in interface is provided above the electronic drawing board 04, allowing the projection module to be inserted at a certain angle and connected to the main control module. The projection module receives projection tasks issued by the main control module and projects standard drawings onto the electronic drawing board. A keyboard module 02 is also provided on one side of the display touch screen 01, allowing the user to adjust the input ratio or perform routine key operations such as opening and selecting menus.

[0042] The touch display module and keyboard module are used to obtain user input instructions, including establishing a drawing task, selecting a drawing template and scale parameters; The main control module is used to calibrate the projection module and the electronic drawing module. According to the instructions input by the user, the main control module sends the graphics to be projected to the projection module for projection display, receives and saves the electronic drawings drawn by the electronic drawing module, and realizes the interaction between the projection module and the electronic drawing module. It also includes the initial synchronous calibration of the projection drawing and the drawing board under the currently selected first scale parameter. Obtain the drawing graphics on the projection drawing, and sequentially collect the electronic drawing graphics formed by the contact signals activated by the drawing board during the drawing process in the drawing order; saving the electronic drawing generated under the first scale parameters; Get the target location point and the second scale parameter selected by the user in the current electronic drawing; Under the currently selected second scale parameter, the projection drawing and drawing board are synchronized again; According to the target location point and the second scale parameter selected by the user, the target area of the projection drawing is enlarged; For the enlarged projection drawing, draw the electronic drawing at the second scale according to the above process; According to the above process, the drawing of the corresponding electronic image under each scale parameter is completed, and the coordinates of the target position point are used as index partition storage until the overall drawing of the electronic drawing is completed.

[0043] Furthermore, preferably, the electronic drawing module includes an electromagnetic induction drawing board and an electronic stylus; the drawing area of the electromagnetic induction drawing board adopts electromagnetic induction technology, and has copper lines arranged evenly horizontally and vertically. The electromagnetic induction board is cut into a certain number of squares, and a balanced criss-cross magnetic field is generated above the board surface; the electronic stylus adopts an EMR passive stylus. When the tip or tail of the pen is close to the drawing board, the internal resonant circuit resonates with the electromagnetic field generated by the drawing board, and the writing operation or erasing operation is achieved by marking the positive and negative of the resonant signal.

[0044] Furthermore, preferably, the projection module is installed on one side of the electromagnetic induction drawing board through an interface, and the angle θ between the projection module and the electromagnetic induction drawing board is in the range of 45°<θ<90°.

[0045] Furthermore, preferably, a binocular recognition camera may be integrated into the projection module, and the binocular recognition camera is used to obtain a depth image of the three-dimensional entity to be drawn.

[0046] The main control module, based on the high-performance Chinese RK3588 CPU, provides functions such as image display control, external communications, and file reading and writing. Its main circuits include the CPU core, power supply, storage, image, audio, and display circuits, USB and network communication circuits, and wireless communication circuits. The module is pre-installed with the Chinese Kylin operating system, serving as a platform for user application software.

[0047] The display touchscreen is a 12.6-inch LCD with integrated backlight control and capacitive touch. The core computing module outputs MIPI-DSI video signals to drive the display image. Touch input is connected to the core computing module via the SPI bus, triggering screen events such as clicks and swipes via interrupts.

[0048] The projection module is a DLP projection device. The core computing module projects the required standard drawings onto the electronic drawing board via HDMI. Considering that the equipment is used during the day, laser light source projection is selected to achieve higher brightness and still present clear images in bright environments.

[0049] The keyboard module has numeric keys, confirm, cancel, X, and Y keys, and is connected to the core computing module through a serial port.

[0050] The electronic drawing tablet utilizes electromagnetic induction technology. The electronic stylus tip moves across the drawing area of the tablet, generating an electrical signal. Through multi-point positioning, the tablet's chip accurately determines the stylus tip's position and transmits this signal to the core computing module via USB. The drawing area of the electronic drawing tablet is 13 inches. Using electromagnetic induction technology, the drawing area features evenly spaced copper lines arranged horizontally and vertically. The electromagnetic induction board is cut into a predetermined number of squares, generating a balanced, crisscrossing magnetic field above the board. To ensure greater drawing accuracy, detail, and smoothness, the drawing area is designed with a resolution of 4096 LPI (lines per inch, horizontally and vertically). Based on the above solution, the electromagnetic induction board for the drawing area was designed and fabricated using PCB processing techniques.

[0051] Common electromagnetic induction pads have varying resolutions, including 2540 LPI, 3048 LPI, 4000 LPI, and 5080 LPI. LPI (Lines Per Inch) directly reflects the density of information the electromagnetic induction pad can recognize and process per unit length. The higher the resolution, the more sensitive the electromagnetic induction pad is to pen position and pressure changes, resulting in higher drawing accuracy. This product has a resolution of 4096 LPI.

[0052] Currently, 5080LPI represents the highest resolution among various electromagnetic induction panels. Theoretically, this high resolution provides electromagnetic induction panels with near-ultra-high precision, meeting the most demanding professional creative requirements. For ultra-high-definition image rendering and detailed 3D model engraving, 5080LPI electromagnetic induction panels offer unparalleled detail, allowing creators to translate their creative ideas into digital images with the utmost precision. However, this cutting-edge technology also presents challenges. 5080LPI electromagnetic induction panels have extremely high requirements for their operating environment. Electromagnetic interference, temperature, and humidity fluctuations can affect their delicate sensing elements, disrupting accurate data reading and causing instability during the drawing process. Furthermore, due to the complexity of their technology, these high-resolution electromagnetic induction panels suffer from relatively poor product stability and are prone to malfunction. This not only increases user costs and maintenance difficulties, but also limits their widespread adoption.

[0053] In contrast, the 4096LPI resolution strikes an excellent balance between precision and stability. After extensive and rigorous testing, choosing 4096LPI as the resolution for electromagnetic induction panels offers numerous advantages. In practical applications, 4096LPI provides exceptionally detailed display effects. During the drawing process, it more than meets the creative needs of designers. Furthermore, its relatively low environmental sensitivity ensures stable performance in a variety of common operating environments.

[0054] Resolution is a key performance indicator of electromagnetic induction boards. 4096LPI has become an ideal choice for electromagnetic induction board resolution due to its comprehensive advantages in accuracy, stability, and environmental adaptability.

[0055] The electronic stylus adopts a passive stylus solution, requiring no charging, allowing uninterrupted drawing. To meet the needs of drawing and erasing, the tip of the electronic stylus is designed as a pencil, and the tail is designed as an eraser. Different signals are sent through a sensing chip to identify writing and erasing operations, thus enabling simultaneous writing and erasing. Traditional styluses often rely on internal batteries. While this ensures independent use to a certain extent, it also brings many inconveniences. Users need to constantly monitor the stylus's battery level. Once the battery runs out, it interrupts their ongoing creative work, teaching, or office work, and the charging process takes a considerable amount of time. The electronic stylus uses EMR (Electro-Magnetic Resonance) technology, which cleverly solves these problems. In this technology system, a precise grid of electromagnetic induction coils is constructed inside the drawing board. When the drawing board is powered on, these coils work together to generate a stable and evenly distributed electromagnetic field. This electromagnetic field, like an invisible energy field, provides the necessary conditions for the passive stylus to operate. A passive stylus, on the other hand, has a built-in resonant circuit. When the stylus is brought close to an arithmetic board, the resonant circuit resonates with the electromagnetic field generated by the arithmetic board. Through this resonance, the stylus draws the required power from the board's electromagnetic field, enabling normal operation. This means that no matter how long the user writes, draws, or manipulates with the stylus, there's no need to worry about running out of power, as the stylus continuously draws energy as long as it's within the effective sensing range of the arithmetic board. Because a passive stylus doesn't require a built-in battery, its structural design is simplified. This not only reduces the stylus' weight, making it easier and more comfortable for users to hold for extended periods, but also reduces the risk of stylus failure.

[0056] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A paperless drawing method, characterized in that: The following steps are involved: S1. Create a drawing task, select a drawing template and the first scale parameter; S2. Perform the first synchronous calibration of the projection drawing and the drawing board under the currently selected first scale parameter; S3. Draw a graphic on the projection drawing, and collect contact signals activated by the drawing board in the drawing process in sequence to form an electronically drawn graphic; S4. Save the electronic drawing generated under the first scale parameters; S5. Obtain the target location point and the second scale parameter selected by the user in the current electronic drawing; S6. Under the currently selected second scale parameter, the projection drawing and the drawing board are synchronized and calibrated again; S7, enlarging the target area of the projection drawing according to the target location point and the second scale parameter selected by the user; S8. For the enlarged projection drawing, draw the electronic drawing under the second scale parameter according to the process of S3 above; S9. Complete the drawing of the corresponding electronic image under each scale parameter according to the above process, and store it in partitions with the coordinates of the target position point as the index until the overall drawing of the electronic drawing is completed.

2. The paperless drawing method according to claim 1, characterized in that: The drawing templates include two-dimensional drawing templates and three-dimensional drawing templates.

3. The paperless drawing method according to claim 1, characterized in that: In S2, the first synchronization calibration of the projection drawing and the drawing board includes: establishing a coordinate mapping model between the projection device and the drawing board based on the installation position relationship between the two, specifically including: The internal and external parameters of the projection equipment are obtained by using the calibration method; Through internal and external parameters, the projection matrix between the image coordinate system of the projection module and the physical coordinate system of the drawing board is established; A multi-point calibration method is used for optimization to solve the projection matrix and obtain an optimized projection matrix; Using the optimized projection matrix, the corrected image is output.

4. The paperless drawing method according to claim 3, characterized in that: The projection matrix between the projection module image coordinate system and the drawing board physical coordinate system, established by the internal and external parameters, is expressed by the following formula: （1） Among them, s is the scale factor, u and v are the projected image coordinates, X and Y are the coordinates of the two-dimensional coordinate system with the drawing board as the plane, H is the projection transformation matrix, R is the rotation matrix, t is the translation vector, and K is the intrinsic parameter matrix.

5. The paperless drawing method according to claim 2, characterized in that: When you select a 3D drawing template, it also includes: Create a first electronic drawing under the current view plane according to the first view plane selected by the user; Extracting vertex coordinates from the first electronic drawing, and when the user selects a second viewing plane, projecting the vertices from the first electronic drawing onto a second electronic drawing to be drawn corresponding to the second viewing plane based on a correspondence between the first viewing plane and the second viewing plane, thereby completing details in the second electronic drawing; And so on, complete the drawing of electronic drawings corresponding to all view planes; The common axes and common vertices in the electronic drawings corresponding to each view plane are extracted and merged to form a three-dimensional electronic drawing.

6. The paperless drawing method according to claim 5, characterized in that: It also includes using a binocular recognition camera to collect multi-angle views of the solid three-dimensional model; extracting edges according to the collected multi-angle views to obtain edge coordinate data; projecting the edge coordinate data corresponding to each angle view onto an electronic drawing of a view plane corresponding to the angle view, performing modifications, and obtaining a three-dimensional view of the solid three-dimensional model.

7. A paperless drawing device, configured to implement the steps of the paperless drawing method according to any one of claims 1 to 6, comprising: Main control module, touch display module, projection module, keyboard module, electronic drawing module; The touch display module and keyboard module are used to obtain user input instructions, including establishing a drawing task, selecting a drawing template and scale parameters; The main control module is used to calibrate the projection module and the electronic drawing module. According to the instructions input by the user, the main control module sends the graphics to be projected to the projection module for projection display, receives and saves the electronic drawings drawn by the electronic drawing module, and realizes the interaction between the projection module and the electronic drawing module. The main control module includes: under the currently selected first scale parameter, performing the initial synchronous calibration of the projection drawing and the drawing board; Obtain the drawing graphics on the projection drawing, and sequentially collect the electronic drawing graphics formed by the contact signals activated by the drawing board during the drawing process in the drawing order; saving the electronic drawing generated under the first scale parameters; Get the target location point and the second scale parameter selected by the user in the current electronic drawing; Under the currently selected second scale parameter, the projection drawing and drawing board are synchronized again; According to the target location point and the second scale parameter selected by the user, the target area of the projection drawing is enlarged; For the enlarged projection drawing, draw the electronic drawing under the second scale parameter according to the above process; According to the above process, the drawing of the corresponding electronic image under each scale parameter is completed, and the coordinates of the target position point are used as index partition storage until the overall drawing of the electronic drawing is completed.

8. The paperless drawing device according to claim 7, characterized in that: The electronic drawing module includes an electromagnetic induction drawing board and an electronic stylus. The drawing area of the electromagnetic induction drawing board uses electromagnetic induction technology. The drawing area is provided with copper lines arranged in a balanced horizontal and vertical manner. The electromagnetic induction board is cut into multiple squares, and a balanced criss-crossing magnetic field is generated above the board surface. The electronic stylus adopts an EMR passive stylus. When the tip or tail of the pen is close to the drawing board, the internal resonant circuit resonates with the electromagnetic field generated by the drawing board. The writing or erasing operation is achieved by marking the positive and negative of the resonant signal.

9. The paperless drawing device according to claim 8, characterized in that: The projection module is installed on one side of the electromagnetic induction drawing board through an interface, and the included angle θ between the projection module and the electromagnetic induction drawing board is in the range of 45°<θ<90°.

10. The paperless drawing device according to any one of claims 7 to 9, characterized in that: It also includes a binocular recognition camera, which is used to obtain a depth image of the three-dimensional entity to be drawn.

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