A method for automatic calibration of water output value based on electromagnetic pen

Abstract

The present invention provides an automatic calibration method for water output value based on an electromagnetic pen, which is used for automatically calibrating the water output value of the electromagnetic pen. The method comprises the following steps: step S1: triggering automatic calibration when the electromagnetic pen enters the writing area from above the writing screen to test the working frequency of the electromagnetic pen; step S2: setting an initial water output value F O , calculate the working frequency of the electromagnetic pen and the initial water value F O Step S3: Set a range interval, when the difference falls into the range interval, reset an instant water value F R ; Step S4: Automatically adjust the instant water output value F R Make the working frequency and initial water value F O The method provided by the present invention reduces the difference between the working frequency and the water output value by instantly calibrating the water output value of the electromagnetic pen, so that the lines drawn by the electromagnetic pen are more delicate and the consistency between the lines is high.

Description

[Technical field]

[0001] The invention relates to the technical field of handwriting electromagnetic pens, and in particular to an automatic calibration method for a water output value based on an electromagnetic pen. [Background technology]

[0002] The electromagnetic ink pen uses electromagnetic screen touch technology to record the electronic trajectory of the pen while writing on paper. The electronic trajectory can record the writing process and content of the electromagnetic pen, and the electronic trajectory can be easily processed and saved. This technology has now been widely used in classroom teaching and distance education.

[0003] The key to electromagnetic pen technology is to sensitively detect its frequency change value. Generally, a set value is given first. When the measured working frequency of the electromagnetic pen is greater than this set value, it is considered that the electromagnetic pen is in contact with the writing surface, and handwriting will be displayed on the computer screen. This set value is called the water output value. The water output value of traditional electromagnetic pens on the market is a fixed value, but the working frequency manufacturing error is large when the electromagnetic pen is suspended in the air, and the working frequency will also change with temperature. This causes a large difference between the working frequency of the electromagnetic pen and the water output value (that is, the water output value setting needs to leave a large safety distance from the working frequency), which means that some electromagnetic pens sometimes produce water with very light force, and sometimes require a lot of force to produce water, resulting in a very poor user experience. [Summary of the invention]

[0004] In order to overcome the problem that the difference in water output values ​​of the existing electromagnetic pens varies greatly, causing inconvenience in use, the present invention provides an automatic calibration method for water output values ​​based on an electromagnetic pen.

[0005] The present invention solves the above technical problems and provides the following technical solutions: The present invention provides an automatic calibration method for water output value based on an electromagnetic pen, which is used to automatically calibrate the water output value of the electromagnetic pen, and is characterized in that the method comprises the following steps: step S1: triggering automatic calibration when the electromagnetic pen enters the writing area from above the writing screen to test the working frequency of the electromagnetic pen; step S2: setting an initial water output value F O , calculate the working frequency of the electromagnetic pen and the initial water value F O Step S3: set a range interval, when the difference obtained in step S2 falls into the range interval, reset an instant water value F R ; Step S4: Automatically adjust the instantaneous water output value F R Make the working frequency of the electromagnetic pen and the initial water value F O The difference ΔF between them is reduced, so that the lines drawn by the electromagnetic pen are more delicate when performing light line drawing operations.

[0006] Preferably, the automatic calibration method of water output value based on the electromagnetic pen further includes a method for triggering the automatic calibration function, and the method for triggering the automatic calibration is: the automatic calibration function is triggered only when the electromagnetic pen is detected for the first time after the MCU is reset or awakened from a sleep state.

[0007] Preferably, alternatively, the method for triggering the automatic calibration is: using the electromagnetic pen to perform a specified action above a specific area to trigger the automatic calibration function, wherein the specified action includes long-term hovering and drawing a circle.

[0008] Preferably, a FLASH storage unit for storing data is provided in the writing screen, and the initial water output value F O is a constant and is stored in the FLASH storage unit.

[0009] Preferably, the writing screen is provided with a data storage device for storing data when power is off, and the instant water output value F R stored in the data storage.

[0010] Preferably, the maximum water output value F of the electromagnetic pen is calculated MAX , minimum water value F MIN , current operating frequency F and minimum safety gap ΔF MIN ; The maximum water value F MAX is the maximum value of the electromagnetic pen's water output, and the minimum water output value F MIN The minimum water discharge value of the electromagnetic pen, the minimum safety gap ΔF MIN is the minimum value of the difference ΔF.

[0011] Preferably, the step S2 further includes the following steps: step S21: performing one or more real-time measurements on the working frequency of the electromagnetic pen to obtain the current working frequency F; the current working frequency F is obtained by calculating the average value of the different working frequencies of the electromagnetic pen at three different time points through a de-interference method; the calculation formula of the current working frequency F is: F = (F1+F2+F3) / 3, where F1, F2, F3 are the working frequencies of the electromagnetic pen at different time points.

[0012] Preferably, the step S2 further comprises the following steps: Step S22: comparing the working frequencies of the electromagnetic pens, when F ≥ F O -ΔF MIN Or F≤F MIN Or F ≥ F MAX Exit auto calibration directly.

[0013] Preferably, the step S2 further comprises the following steps: Step S23: When F MIN ≤F≤F O -ΔFMIN or F O ≤F≤F MAX When the automatic calibration is carried out, the instantaneous water output value F R =F-ΔF MIN .

[0014] Preferably, the water output value is a preset working frequency value. When the working frequency of the electromagnetic pen is greater than the water output value, it is determined that the electromagnetic pen has touched the writing screen, and then the writing screen displays the handwriting of the electromagnetic pen.

[0015] Compared with the prior art, the automatic calibration method of water output value based on electromagnetic pen provided by the present invention has the following advantages:

[0016] (1) In the method for automatic calibration of water flow value based on an electromagnetic pen involved in the present invention, the automatic calibration of the water flow value of the electromagnetic pen can be completed unconsciously without the user operating the electromagnetic pen. When the sensing device detects that the stylus (i.e., the electromagnetic pen) enters the preset handwriting area from above the writing surface (i.e., the writing screen), the system starts to test the working frequency of the stylus when it is suspended in the air, and calculates the difference between the working frequency when it is suspended in the air and the initial water flow value. When the difference reaches a certain range, a water flow value is reset, and this new water flow value is called the instant water flow value. It can be understood that by automatically adjusting the water flow value of the electromagnetic pen for multiple times, the difference between the frequency when the electromagnetic pen is suspended in the air and the water flow value is gradually reduced, so that the consistency of the lines drawn by the electromagnetic pen is better, and the method provided by the present invention makes the lines drawn by the electromagnetic pen more delicate when drawing light lines through instant calibration, that is, the handwriting display on the writing screen is smoother.

[0017] (2) In the automatic calibration method of water output value based on the electromagnetic pen involved in the present invention, the water output value is compared with the original water output value, that is, the currently measured working frequency of the electromagnetic pen is compared with the designed original water output value. The original water output value is a constant in the set software and is stored in the program FLASH. There is no need to add additional memory in the system, which further reduces the cost.

[0018] (3) The method for automatic calibration of water output value based on the electromagnetic pen involved in the present invention is provided with a plurality of ways to trigger the automatic calibration function, each of which has its own characteristics. The user can select the triggering method of the automatic calibration function, and the applicability is strong; among these methods for triggering automatic calibration, one of them is to automatically calibrate the electromagnetic pen each time it is detected to appear in the writing area. The reaction speed and reporting rate of this method are relatively low, but the processing efficiency is effectively improved and the missed detection rate is reduced; among these methods for triggering automatic calibration, one of them is to automatically calibrate the water output value only when the electromagnetic pen is detected for the first time after the system MCU is reset or awakened from sleep mode. This method not only effectively improves the work efficiency, but also simplifies the calculation process; further, the user can hold the electromagnetic pen and make a certain action above the writing screen to trigger the automatic calibration function of the system, such as hovering over the sensing area for a long time, drawing a circle over a specific area, etc., so that the user can easily and conveniently start the automatic calibration function when it needs to be triggered, without the need for other complicated operations, which greatly improves the convenience of the system.

Brief Description of the Drawings

[0019] Figure 1 It is a schematic flow chart of a method for automatic calibration of water output value based on an electromagnetic pen provided in the first embodiment of the present invention;

[0020] Figure 2 It is a schematic flow chart of step S2 of a method for automatic calibration of water output value based on an electromagnetic pen provided in the first embodiment of the present invention. [Specific implementation method]

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0023] Please refer to Figure 1-Figure 2The first embodiment of the present invention provides a method for automatically calibrating the water output value based on an electromagnetic pen, which is used to automatically calibrate the water output value of the electromagnetic pen. The method comprises the following steps: step S1: triggering automatic calibration when the electromagnetic pen enters the writing area from above the writing screen to test the working frequency of the electromagnetic pen; step S2: setting an initial water output value F O , calculate the working frequency of the electromagnetic pen and the initial water value F O Step S3: set a range interval, when the difference obtained in step S2 falls into the range interval, reset an instant water value F R ; Step S4: Automatically adjust the instantaneous water output value F R Make the working frequency of the electromagnetic pen and the initial water value F O The difference ΔF between them is reduced, so that the lines drawn by the electromagnetic pen are more delicate when performing light line drawing operations.

[0024] Specifically, the electromagnetic handwriting system receives and processes the electromagnetic induction signal of the electromagnetic pen to calculate the electromagnetic pen's working frequency. The electromagnetic pen's working frequency can determine whether the electromagnetic pen is in contact with the writing surface and the pressure applied to the electromagnetic pen by the writer. There are two ways in which the electromagnetic pen's working frequency changes with pressure: one is that as the pressure increases, the electromagnetic pen's working frequency also increases (positive correlation), and the other is that as the pressure increases, the electromagnetic pen's working frequency decreases (negative correlation) (the following description mainly uses positive correlation, and negative correlation is similar). Generally, a set value is given first. For the positive correlation method, if the measured working frequency is greater than this set value, it is considered that the electromagnetic pen is in contact with the writing surface, and handwriting will be displayed on the computer screen. This set value is usually called the water output value.

[0025] It can be understood that in the automatic calibration method of water outlet value based on electromagnetic pen provided in the first embodiment of the present invention, the automatic calibration of water outlet value of electromagnetic pen can be completed unconsciously without the user operating and controlling the electromagnetic pen. When the sensing device detects that the stylus (i.e., electromagnetic pen) enters the preset handwriting area from above the writing surface (i.e., writing screen), the system starts to test the working frequency of the stylus when it is suspended in the air, and calculates the difference between the working frequency when suspended in the air and the initial water outlet value. When this difference reaches a certain range, a water outlet value is reset, and this new water outlet value is called the instant water outlet value. It can be understood that by automatically adjusting the water outlet value of the electromagnetic pen for multiple times, the difference between the frequency when the electromagnetic pen is suspended in the air and the water outlet value is gradually reduced, so that the lines drawn by the electromagnetic pen are more consistent, and the method provided by the present invention makes the electromagnetic pen draw more delicate lines when drawing light lines through instant calibration, that is, the handwriting display on the writing screen is smoother.

[0026] Specifically, the automatic calibration method of water output value based on the electromagnetic pen further includes a method for triggering the automatic calibration function. The method for triggering the automatic calibration is: the automatic calibration function is triggered only when the electromagnetic pen is detected for the first time after the MCU is reset or awakened from a sleep state.

[0027] Specifically, or, the method for triggering the automatic calibration is: using the electromagnetic pen to perform a specified action above a specific area to trigger the automatic calibration function, wherein the specified action includes long-term hovering and circling.

[0028] Specifically, a FLASH storage unit for storing data is provided in the writing screen, and the initial water output value F O It is a constant and is stored in the FLASH storage unit; it can be understood that, compared with the original water output value, that is, the currently measured working frequency of the electromagnetic pen is compared with the designed original water output value, the original water output value is a constant in the set software and is stored in the program FLASH, and there is no need to add additional memory in the system, which further reduces the cost.

[0029] Specifically, the writing screen is provided with a data storage device for storing data when power is off. R stored in the data storage.

[0030] Specifically, the maximum water output value F of the electromagnetic pen is calculated. MAX , minimum water value F MIN , current operating frequency F and minimum safety gap ΔF MIN ; The maximum water value F MAX is the maximum value of the electromagnetic pen's water output, and the minimum water output value F MIN The minimum water discharge value of the electromagnetic pen, the minimum safety gap ΔF MIN is the minimum value of the difference ΔF.

[0031] Please continue reading Figure 2 , the step S2 further includes the following steps: step S21: perform one or more real-time measurements on the working frequency of the electromagnetic pen to obtain the current working frequency F; the current working frequency F is calculated by averaging the different working frequencies of the electromagnetic pen at three different time points through a de-interference method; the calculation formula of the current working frequency F is: F=(F1+F2+F3) / 3, where F1, F2, and F3 are the working frequencies of the electromagnetic pen at different time points.

[0032] Specifically, the step S2 further includes the following steps: Step S22: First make a judgment, when F ≥ F O -ΔF MIN Or F≤F MIN Or F ≥ FMAX Exit automatic calibration directly (no calibration is required when the water output value is normal or the electromagnetic pen is damaged and the frequency deviation is too large).

[0033] Specifically, the step S2 further includes the following steps: Step S23: When F MIN ≤F≤F O -ΔF MIN (In this case, the electromagnetic pen's working frequency deviates greatly, and it is difficult to draw water when drawing light lines. The problem of excessive water pressure can be solved through automatic adjustment) or F O ≤F≤F MAX (In this case, the electromagnetic pen has the original water value F O The setting is unreasonable and water leakage has occurred. Through automatic adjustment, the electromagnetic pen leakage problem can be solved). Calibration is required. The instant water value F R =F-ΔF MIN .

[0034] Further, the automatic calibration method for water output value based on the electromagnetic pen provided in the first embodiment of the present invention is provided with a plurality of ways to trigger the automatic calibration function, each triggering method has its own characteristics, and the user can select the triggering method of the automatic calibration function, which has strong applicability; among these methods for triggering automatic calibration, one of the methods is to automatically calibrate the electromagnetic pen every time it is detected to appear in the writing area. The reaction speed and reporting rate of this method are relatively low, but the processing efficiency is effectively improved and the missed detection rate is reduced; among these methods for triggering automatic calibration, one of the methods is to automatically calibrate the water output value only when the electromagnetic pen is detected for the first time after the system MCU is reset or awakened from sleep. This method not only effectively improves work efficiency, but also simplifies the calculation process; further, the user can hold the electromagnetic pen and make a certain action above the writing screen to trigger the automatic calibration function of the system, such as hovering over the sensing area for a long time, drawing a circle over a specific area, etc., so that the user can easily and conveniently start the automatic calibration function when it needs to be triggered, without the need for other complicated operations, which greatly improves the convenience of the system.

[0035] Specifically, the water output value is a preset working frequency value. When the working frequency of the electromagnetic pen is greater than the water output value, it is determined that the electromagnetic pen has touched the writing screen, and then the writing screen displays the handwriting of the electromagnetic pen.

[0036] Compared with the prior art, the automatic calibration method of water output value based on electromagnetic pen provided by the present invention has the following advantages:

[0037] (1) In the method for automatic calibration of water flow value based on an electromagnetic pen involved in the present invention, the automatic calibration of the water flow value of the electromagnetic pen can be completed unconsciously without the user operating the electromagnetic pen. When the sensing device detects that the stylus (i.e., the electromagnetic pen) enters the preset handwriting area from above the writing surface (i.e., the writing screen), the system starts to test the working frequency of the stylus when it is suspended in the air, and calculates the difference between the working frequency when it is suspended in the air and the initial water flow value. When the difference reaches a certain range, a water flow value is reset, and this new water flow value is called the instant water flow value. It can be understood that by automatically adjusting the water flow value of the electromagnetic pen for multiple times, the difference between the frequency when the electromagnetic pen is suspended in the air and the water flow value is gradually reduced, so that the consistency of the lines drawn by the electromagnetic pen is better, and the method provided by the present invention makes the lines drawn by the electromagnetic pen more delicate when drawing light lines through instant calibration, that is, the handwriting display on the writing screen is smoother.

[0038] (2) In the automatic calibration method of water output value based on the electromagnetic pen involved in the present invention, the water output value is compared with the original water output value, that is, the currently measured working frequency of the electromagnetic pen is compared with the designed original water output value. The original water output value is a constant in the set software and is stored in the program FLASH. There is no need to add additional memory in the system, which further reduces the cost.

[0039] (3) The method for automatic calibration of water output value based on the electromagnetic pen involved in the present invention is provided with a plurality of ways to trigger the automatic calibration function, each of which has its own characteristics. The user can select the triggering method of the automatic calibration function, and the applicability is strong; among these methods for triggering automatic calibration, one of them is to automatically calibrate the electromagnetic pen each time it is detected to appear in the writing area. The reaction speed and reporting rate of this method are relatively low, but the processing efficiency is effectively improved and the missed detection rate is reduced; among these methods for triggering automatic calibration, one of them is to automatically calibrate the water output value only when the electromagnetic pen is detected for the first time after the system MCU is reset or awakened from sleep mode. This method not only effectively improves the work efficiency, but also simplifies the calculation process; further, the user can hold the electromagnetic pen and make a certain action above the writing screen to trigger the automatic calibration function of the system, such as hovering over the sensing area for a long time, drawing a circle over a specific area, etc., so that the user can easily and conveniently start the automatic calibration function when it needs to be triggered, without the need for other complicated operations, which greatly improves the convenience of the system.

Claims

1. A method for automatically calibrating the water output value of an electromagnetic pen, which is used to automatically calibrate the water output value of an electromagnetic pen, characterized in that: The method comprises the following steps, Step S1: triggering automatic calibration when the electromagnetic pen enters the writing area from above the writing screen, and testing the working frequency of the electromagnetic pen when it is suspended in the air; Step S2: Set a water output value as the initial water output value F O , calculate the working frequency of the electromagnetic pen when it is suspended and the initial water output value F O The difference between ΔF; Step S3: Set a range interval. When the difference value obtained in step S2 falls into the range interval, a water output value is reset as the instantaneous water output value F. R ; Step S4: Automatically adjust the instantaneous water output value F R The difference between the working frequency and the water output value of the electromagnetic pen when it is suspended in the air is reduced, so that the lines drawn by the electromagnetic pen during light line drawing operation are more delicate. The water output value is a preset working frequency value. When the working frequency of the electromagnetic pen is greater than the water output value, it is determined that the electromagnetic pen has touched the writing screen, and then the writing screen displays the handwriting of the electromagnetic pen.

2. The method for automatic calibration of water output value based on electromagnetic pen according to claim 1, characterized in that: The automatic calibration method for water output value based on the electromagnetic pen further includes a method for triggering the automatic calibration function. The method for triggering the automatic calibration is: the automatic calibration function is triggered only when the electromagnetic pen is detected for the first time after the MCU is reset or awakened from a sleep state.

3. The method for automatic calibration of water output value based on electromagnetic pen as claimed in claim 2, characterized in that: Alternatively, the method for triggering the automatic calibration is: using the electromagnetic pen to perform a specified action above a specific area to trigger the automatic calibration function, wherein the specified action includes long-term hovering and drawing a circle.

4. The method for automatic calibration of water output value based on electromagnetic pen according to claim 1, characterized in that: A FLASH storage unit for storing data is provided in the writing screen. The initial water output value F O is a constant and is stored in the FLASH storage unit.

5. The method for automatic calibration of water output value based on electromagnetic pen according to claim 1, characterized in that: The writing screen is provided with a data storage device for storing data when power is off. R stored in the data storage.

6. The method for automatic calibration of water output value based on electromagnetic pen according to claim 1, characterized in that: Calculate the maximum water output value F of the electromagnetic pen MAX , minimum water value F MIN , current operating frequency F and minimum safety gap ΔF MIN ; The maximum water output value F MAX is the maximum value of the electromagnetic pen's water output, and the minimum water output value F MIN The minimum water discharge value of the electromagnetic pen, the minimum safety gap ΔF MIN is the minimum value of the difference ΔF.

7. The method for automatic calibration of water output value based on electromagnetic pen according to claim 6, characterized in that: The step S2 further comprises the following steps: Step S21: performing one or more real-time measurements on the operating frequency of the electromagnetic pen when it is suspended in the air to obtain the current operating frequency F; The current operating frequency F is obtained by calculating the average value of different operating frequencies of the electromagnetic pen at three different time points through a three-point de-interference method; The calculation formula of the current working frequency F is: F=(F1+F2+F3) / 3, wherein F1, F2, and F3 are the working frequencies of the electromagnetic pen at different time points.

8. The method for automatic calibration of water output value based on electromagnetic pen according to claim 7, characterized in that: The step S2 further comprises the following steps: Step S22: Compare the working frequencies of the electromagnetic pens. When F ≥ F O -ΔF MIN Or F≤F MIN Or F ≥ F MAX Exit auto calibration directly.

9. The method for automatic calibration of water output value based on electromagnetic pen according to claim 8, characterized in that: The step S2 further comprises the following steps: Step S23: When F MIN ≤F≤F O -ΔF MIN or F O ≤F≤F MAX When the automatic calibration is carried out, the instantaneous water output value F R =F-ΔF MIN .

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