Moving trajectory calibration method and moving trajectory generation method

Movement trajectory correction method and movement trajectory generation method

MOVING TRAJECTORY CALIBRATION METHOD AND MOVING TRAJECTORY GENERATION METHOD

The present invention relates to a method for correcting movement trajectory and a method for generating movement trajectory.

In recent years, the rapid development of electronic circuits and components in miniaturization technology has greatly reduced the volume and weight of electronic devices, and has increased their functionality, portability, and convenience. Due to the above-mentioned major changes in technology, the technology of human-computer interaction (HCI) has become an indispensable part of daily life. Among them, the writing in the human-machine interface is an indispensable method of recording or expressing consciousness in ordinary people's daily life. At present, there are many man-machine interface sensing technologies for handwriting input in the market, which can be roughly divided into five types: electromagnetic, electronic, ultrasonic, pressure and optical sensing.

In the electromagnetic human-machine interface sensing technology, because it requires a lot of power to generate electromagnetic fields to detect and locate the writing position of the pen tip of the writing device, a larger battery is needed to provide power, which causes the weight of the writing device to be heavier. And there is the disadvantage of inconvenience to carry. In terms of electronic man-machine interface sensing technology, it needs to be matched with a specific electrode paper, and the transmission electrode and the receiving electrode on the electrode paper are used to detect the trajectory of the writing device. However, the high unit price of electrode paper is the main reason for the current low consumer acceptance. In terms of ultrasonic human-machine interface sensing technology, it uses the time difference between ultrasonic waves to reach the receiving end and the principle of triangulation to calculate the writing track coordinates of the pen tip of the writing device. It can accurately capture the movement track of the writing device on any plane, but it needs to be equipped with an ultrasonic receiving device, and the ultrasonic receiving range is small, which causes inconvenience in use. In terms of pressure human-machine interface sensing technology, the writing range is limited to a certain area of the pressure sensing electronic board, which also causes inconvenience for the user to use. In addition, the optical human-machine interface sensing technology mainly uses the optical sensor in the optical mouse to sense the track of the writing device on the writing plane. The sensing principle is the same as that of an optical mouse, so it is very easy to convert the movement track information into a signal for controlling the mouse without developing additional human-machine interface software.

However, no matter which kind of sensing technology writing device is in the writing process, it may leave the two-dimensional plane of writing due to pen lifting or line change, but at the same time, the sensing element still continues to output the sensing signal, therefore, an error will be generated The trajectory of the movement.

Therefore, how to provide a movement trajectory correction method and a movement trajectory generation method that can detect and correct errors in the movement trajectory caused by pen lifting or line change to obtain the correct movement trajectory has become one of the important issues.

In view of the above-mentioned problems, the object of the present invention is to provide a method for correcting movement and generating method for movement trajectory that can detect and correct the error of the movement trajectory of the writing device due to pen lifting or line change, so as to obtain the correct movement trajectory.

In order to achieve the above-mentioned object, a movement track correction method according to the present invention is to receive a movement when a writing device moves on a writing plane. The trajectory signal, and includes: a first-axis signal, a second-axis signal, and a third-axis signal are generated by a detection and correction unit of a posture calculation module according to the movement trajectory signal, and the writing plane is determined by The first axis and the second axis are formed, and the third axis is perpendicular to the writing plane; the first axis signal is corrected by the detection and correction unit according to the third axis signal to generate a first axis track signal ; And the second-axis signal is corrected by the detection and correction unit according to the third-axis signal to generate a second-axis trajectory signal.

In one embodiment, the movement trajectory signal includes a triaxial angular velocity signal of the movement trajectory at different times, an acceleration signal, a magnetic field strength signal, a geomagnetic azimuth signal, or a combination thereof.

In one embodiment, the first axis, the second axis, and the third axis are perpendicular to each other.

In one embodiment, the step of calibrating the first-axis signal further includes: when the change of the third-axis signal in a period of time exceeds a predetermined signal value, the detecting and correcting unit uses The first axis signal is zero.

In one embodiment, the step of calibrating the second-axis signal further includes: when the change of the third-axis signal in a period of time exceeds a predetermined signal value, the detection and correction unit is used to make the signal within a period of time The second axis signal is zero.

To achieve the above objective, a method for generating a movement track according to the present invention includes: generating a movement track when the writing device moves on a writing plane through a movement track sensing module of a writing device, and generating a movement Track signal; a detection and correction unit of a posture calculation module generates a first axis signal, a second axis signal and a third axis signal according to the movement track signal, wherein the writing plane is set by the first axis And the second axis Formed, and the third axis is perpendicular to the writing plane; the first axis signal and the second axis signal are respectively corrected by the detection and correction unit according to the third axis signal to generate a first axis track signal and a A second axial trajectory signal; and a display module displays the corrected movement trajectory according to the first axial trajectory signal and the second axial trajectory signal.

In one embodiment, the movement trajectory generation method further includes: generating a coordinate conversion matrix according to the angular velocity signal by a posture conversion unit of the posture calculation module, and performing coordinate conversion on the acceleration signal according to the coordinate conversion matrix.

In one embodiment, the attitude conversion unit integrates the angular velocity signal once to obtain an attitude angle, and then generates a coordinate conversion matrix, and uses the coordinate conversion matrix to convert the acceleration signal to convert the acceleration signal from a body coordinate system of the writing device It is a reference coordinate system.

In one embodiment, the method for generating the movement trajectory further includes: performing gravity compensation on the acceleration signal of the reference coordinate system by a gravity compensation unit of the posture calculation module.

In one embodiment, the movement trajectory generation method further includes: a trajectory calculation unit of the posture calculation module separately calculates the first axial trajectory signal and the second axial trajectory signal.

In one embodiment, the drawing plane includes a horizontal plane, a vertical plane, or an inclined plane.

As mentioned above, in the movement trajectory correction method and movement trajectory generation method of the present invention, a detection and correction unit of a posture calculation module respectively generates a first axis signal and a second axis signal according to the movement trajectory signal. Axial information Signal and a third axis signal, wherein the writing plane is formed by the first axis and the second axis, and the third axis is perpendicular to the writing plane, and the detection and correction unit is respectively based on the third axis signal The first axis signal and the second axis signal are calibrated to generate a first axis track signal and a second axis track signal respectively, and then the display module is used according to the first axis track signal and the second axis signal The trajectory signal shows the trajectory after calibration. Thereby, the movement trajectory correction method and movement trajectory generation method of the present invention can detect and correct the error of the movement trajectory caused by pen lifting or line change, so as to obtain the correct movement trajectory.

Hereinafter, a method for correcting a movement track and a method for generating a movement track according to a preferred embodiment of the present invention will be described with reference to related drawings, wherein the same components will be described with the same reference signs.

Please refer to FIG. 1A and FIG. 1B, which are respectively a schematic diagram of a writing device 1 when writing on a writing plane P and its functional block diagram.

The writing device 1 is a writing device using inertial sensing elements, which mainly uses inertial elements to sense the angle, posture, and displacement of the writing device in a three-dimensional space. Here, the form of the writing device 1 is a pen as an example. However, the form is not limited to a pen shape, and may also be in other forms or forms, such as a mouse that can be held by a human or other forms.

As shown in FIG. 1B, the writing device 1 may include a movement track sensing module. In addition, the writing device 1 may also include a posture calculation module. However, in other embodiments, another processing device (for example, one with a display screen) The computer) can also include the posture calculation module, and can transmit the signal generated by the movement trajectory sensing module to the posture calculation module for calculation in a wired or wireless manner.

The movement trajectory sensing module can sense a movement trajectory generated when the writing device 1 moves in the three-dimensional space, and generate a movement trajectory signal in real time. Among them, the movement trajectory sensing module may include a multi-axis dyamic switch. The movement track can be a number, a character, a symbol, a line or an arbitrary writing track. In addition, the movement track signal may include coordinate information, angular velocity information, gravity information, acceleration information, magnetic field strength information, geomagnetic azimuth information, or other information of the movement track at different points in time, or a combination thereof. In addition, the drawing plane P can be, for example, a horizontal plane, a vertical plane or an inclined plane. Here, a horizontal plane is taken as an example.

The movement trajectory sensing module may include, for example, a gyroscope, an accelerometer, a magnetometer, or an electronic compass, or a combination of the above-mentioned instruments. The above-mentioned instruments may be single-axis or multi-axis (for example, three-axis), and the movement trajectory The signal may include a triaxial angular velocity signal, an acceleration signal, a magnetic field strength signal, a geomagnetic azimuth signal, or a combination of the three-axis angular velocity signal of the moving track at different times. Here, it is taken as an example that the movement trajectory sensing module has a three-axis gyroscope and an accelerometer, and measures the angular velocity signal, gravity g, and acceleration signal in the three-axis direction. Firstly, the writing device 1 or another processing device may further include a calibration filter unit (not shown in the figure). The calibration filter unit can calibrate the inertial elements in the movement track sensing module (such as the above-mentioned gyroscope, acceleration, etc.). The signal generated by the meter, magnetometer or electronic compass, or a combination thereof), and can filter out the noise generated by the inertial element itself or the influence of hand movement during writing. Noise (such as tremor) and other influences caused by the external environment lead to errors in the movement track signal.

In this embodiment, the following pre-processing is required to obtain the movement trajectory signal (the angular velocity signal and the acceleration signal in this embodiment) before the steps of the movement trajectory correction method of the present invention can be performed. Among them, as shown in FIG. 1B, the angular velocity signals in the three-axis direction need to be integrated by a posture conversion unit of the posture calculation module to obtain an posture angle of the writing device 1 when writing. Among them, the attitude angle can include a roll angle<i>Φ</i>(roll angle), a pitch angle θ (pitch angle) and a yaw angle ψ (yaw angle). The main function of the posture angle is to obtain the relative angle or rotation relationship between the body frame and the local level frame of the writing device 1.

Wherein, the roll angle is the angle at which the writing device 1 rotates along a first axis of the body coordinate system, which can be obtained by measuring the angular velocity of the writing device 1 in the first direction through one integration. Furthermore, in other embodiments, the roll angle can also be the angle at which the writing device 1 rotates along the first direction, which can be obtained by measuring the earth's gravity component in three directions of the accelerometer in the writing device 1 . In addition, the pitch angle is the angle at which the writing device 1 rotates along a second direction, which can be obtained by one integration after measuring the angular velocity of the writing device 1 in the second direction. Furthermore, in other embodiments, the pitch angle can also be the angle at which the writing device 1 rotates along the second direction, which can be obtained by measuring the earth's gravity component in the three directions of the accelerometer in the writing device 1. In addition, the yaw angle is the angle at which the writing device 1 rotates along a third direction, which can be used to measure the angular velocity of the writing device 1 in the third direction. After that, it is obtained through one integration. Furthermore, in other embodiments, the yaw angle can also be the angle at which the writing device 1 rotates along the third direction, which can be measured by measuring the magnetic field strength measured by the magnetometer in the writing device 1 or the electronic compass. Obtained by measuring the geomagnetic azimuth. Furthermore, the roll angle, pitch angle and yaw angle can also be obtained by measuring the magnetic field strength or the geomagnetic azimuth of the writing device 1, or a combination thereof. Here, there is no restriction.

Then, the posture conversion unit generates a coordinate conversion matrix based on the angular velocity signal and its posture angle, and uses the coordinate conversion matrix to convert the acceleration signal generated by the movement track sensing module from the body coordinate system of the writing device 1 to the reference coordinate system. In addition, the acceleration signal is compensated for gravity by a gravity compensation unit of the attitude calculation module to remove the acceleration change caused by the influence of gravity, and then the movement is detected by one of the attitude calculation modules by the correction unit. Correction of trajectory. Among them, the above-mentioned coordinate conversion and gravity compensation techniques are commonly used by those skilled in the art, and will not be further described here.

Please refer to FIG. 2A first. Here, the number "4" written by the writing device 1 is taken as an example. Wherein, when writing "4", the movement trajectory of FIG. 2A from position A to position B is generated by the writing device 1 as a result of lifting the pen and changing lines. Therefore, the trajectory correction method can be performed according to the movement trajectory correction method of the present invention to eliminate The trajectory generated by the pen lift and line change (that is, the movement trajectory between position A and position B is removed), and then the correct trajectory "4" as shown in FIG. 2B is obtained.

Please refer to FIG. 1R and FIG. 1C, where 1C is a flow chart of a method for correcting movement trajectory according to a preferred embodiment of the present invention.

The movement trajectory correction method of the present invention can receive the movement trajectory signal generated when the writing device 1 moves on the writing plane P, and the preprocessing of the movement trajectory signal has been described in detail above, and will not be repeated here.

In addition, please refer to Figure 3A, which is the first axis X of the body coordinate system after the above-mentioned pre-processing (such as calibration, filtering, etc.) in the movement trajectory signal output by the movement trajectory sensing module , Schematic diagram of acceleration signals in the second axis Y and the third axis Z. In addition, please refer to FIG. 3B, which is a schematic diagram of the waveform of the movement track signal of FIG. 3A after coordinate conversion. Here, the acceleration signal of the body coordinate system is converted into the acceleration signal of the reference coordinate system. As shown in FIG. 3B, the reference system of the third axis Z is 1g, and the reference system of the first axis X and the second axis Y are respectively 0g. In addition, please refer to FIG. 3C, which is a waveform diagram of the motion track signal of FIG. 3B after gravity compensation. It can be seen from FIG. 3C that the acceleration signal of the reference coordinate system can be compensated by the gravity compensation unit to remove the influence of acceleration due to gravity. As shown in FIG. 3C, the reference of the first axis X, the second axis Y, and the third axis Z are all 0g.

As shown in FIG. 1C, the movement trajectory correction method of the present invention includes the following steps P01 to P03.

First, step P01 is: a first-axis signal, a second-axis signal, and a third-axis signal are respectively generated by a detection and correction unit of a posture calculation module according to the movement track signal, wherein the writing plane P is formed by the first axis and the second axis, and the third axis is perpendicular to the writing plane. In this embodiment, the first axis, the second axis, and the third axis are three mutually perpendicular axes of the reference coordinate system, namely X, Y, and Z in FIG. 2A. The writing plane P is formed by the first axis X and the second axis Y, and the third axis Z is perpendicular to the writing plane P. In addition, the first axis signal, the second axis signal, and the third axis signal (acceleration signal) are shown in FIGS. 4A to 4C, respectively. However, in other embodiments, if the writing plane is a vertical plane, such as the plane formed by the axis X and the axis Z in FIG. 2A, the third axis is Y.

Next, proceed to step P02, which is to calibrate the first-axis signal according to the third-axis signal by the detection and correction unit to generate a first-axis trajectory signal. In this embodiment, since the third-axis signal is generated by pen lifting or line change, the third-axis signal is used to correct the first-axis signal and the second-axis signal. Wherein, in the step of calibrating the signal of the first axis, it may further include when the change of the signal of the third axis in a period of time exceeds a preset signal value, the first axis is activated by the detecting and correcting unit within the period of time. The direction signal is zero. In other words, the third-axis signal is generated by the pen or line change, so it is an unnecessary signal. Therefore, the third-axis signal changes within a period of time (that is, between time t1 and time t2 in Figure 4C). When the value exceeds the preset signal value, it can be known that it is caused by pen lifting or line change. Therefore, the signal of the first axis X at the same time must be eliminated so that the first axis signal is zero (Figure 4A only shows that segment The first axis signal of time does not show that the first axis signal of that period of time is zero). Among them, the preset signal value can be customized by the user.

Finally, step P03 is performed to calibrate the second-axis signal according to the third-axis signal by the detection and correction unit to generate a second-axis trajectory signal. In the same way, when the change of the third-axis signal in a period of time exceeds a preset signal value, the detection and correction unit makes the second-axis signal within that period of time Is zero. Therefore, the signal of the second axis Y in the same time is also eliminated, so that the signal of the second axis is zero (Figure 4B only shows the signal of the second axis of the period of time, and does not show the signal of the second axis of the period of time. The direction signal is zero). It is worth mentioning that the sequence of steps P02 and P03 described above is only an example, and the present invention is not limited. It is also possible to perform step P03 first and then perform step P02, or perform step P02 and step P03 at the same time.

In addition, please refer to FIG. 5A and FIG. 5B, which are respectively a step flow chart and a functional block diagram of a method for generating a movement track of the present invention.

The method for generating a movement track of the present invention includes: a movement track sensing module of a writing device 1 senses a movement track when the writing device 1 moves on a writing plane P, and generates a movement track signal ( Step S01). A first-axis signal, a second-axis signal, and a third-axis signal are generated by a detection and correction unit of a posture calculation module according to the movement track signal, wherein the writing plane P is determined by The first axis and the second axis are formed, and the third axis is perpendicular to the writing plane P (step S02), and the first axis signal and the second axis signal are corrected by the detection and correction unit according to the third axis signal. Axial signals to generate a first axial trajectory signal and a second axial trajectory signal respectively (step S03). Here, step S01 has been described in detail above, and steps S02 to S03 can refer to the above steps P01 to P03, and will not be repeated.

In addition, the movement track generation method of the present invention may further include step S04: display the corrected movement track based on the first axis track signal and the second axis track signal by a display module. In other words, as shown in Figure 2B, a computer with a display screen can be used, for example, to display the correct Movement track. In this embodiment, as shown in FIG. 2B, since the acceleration signal of the third axis Z generated by the pen lifting or line change has been removed from the first axis signal and the second axis signal, the acceleration signal of the third axis Z generated by The display module displays the correct movement track after correction according to the first axis track signal and the second axis track signal. It is also mentioned that before step S04, as shown in FIG. 5B, the method for generating the movement trajectory may further include: using a trajectory calculation unit of the posture calculation module to separately calculate the first axial trajectory signal and the second axial trajectory The signal is calculated. Here, two integrations are performed so that the acceleration signals of the first axis and the second axis are respectively converted into a displacement signal, and the display module converts the displacement signal into a movement track and displays it.

In addition, other technical features of the method for generating movement trajectories have been described in detail above, and will not be repeated here.

In addition, please refer to FIG. 6A and FIG. 6B. Among them, FIG. 6A is a schematic diagram of the movement trajectory of writing the number "12" with the writing device 1, and FIG. 6B is the movement trajectory generation method of the present invention. Schematic diagram of the movement track displayed. In addition, please refer to FIG. 7A and FIG. 7B. Among them, FIG. 7A is a schematic diagram of the movement track of writing the number "86" with the writing device 1, and FIG. Schematic diagram of the movement trajectory.

In FIG. 6A and FIG. 7A, the movement track between the position A and the position B is still the movement track generated by lifting the pen or changing the line. Therefore, as shown in FIG. 6B and FIG. 7B, the movement trajectory generation method of the present invention can detect and correct the error of the movement trajectory caused by pen lifting or line change, so as to obtain the correct movement trajectory.

In summary, in the movement trajectory correction method and movement trajectory generation method of the present invention, a detection and correction unit of a posture calculation module generates a first axis signal and a second axis signal according to the movement trajectory signal. Axial signal and a third-axis signal, wherein the writing plane is formed by the first and second axes, and the third axis is perpendicular to the writing plane, and the detection and correction unit is based on the third axis The signal calibrates the first axis signal and the second axis signal respectively to generate a first axis track signal and a second axis track signal, and then the display module is used according to the first axis track signal and the second axis track signal. The axial track signal displays the corrected movement track. Thereby, the movement trajectory correction method and movement trajectory generation method of the present invention can detect and correct the error of the movement trajectory caused by pen lifting or line change, so as to obtain the correct movement trajectory.

The above description is only illustrative, and not restrictive. Any equivalent modifications or alterations that do not depart from the spirit and scope of the present invention should be included in the scope of the appended patent application.

<p>1Writing device</p><p>A, Blocation</p><p>Pwriting plane</p><p>P01~P03, S01~S04Step</p><p>t1, t2time</p><p>X, Y, Zaxial</p>

Figures 1A and 1B are respectively a schematic diagram of a writing device when writing on a writing plane and its functional block diagram; Figure 1C is a step flow chart of a method for correcting movement trajectories according to a preferred embodiment of the present invention; Figure 2A is A schematic diagram of the movement trajectory of the writing device writing the number "4"; FIG. 2B is the movement trajectory generation method in FIG. 2A using the present invention Then, the schematic diagram of the movement track displayed by the display module; Fig. 3A is the waveform schematic diagram of the three-axis acceleration signal of the movement track signal; Fig. 3B is the waveform schematic diagram of the movement track signal of Fig. 3A after coordinate conversion; Fig. 3C is Fig. 3B Schematic diagram of the waveform of the movement track signal after gravity compensation; Figures 4A to 4C are the waveform diagrams of the first axis signal, the second axis signal and the third axis signal, respectively; Figures 5A and 5B are respectively a kind of the present invention Figure 6A is a schematic diagram of the movement trajectory of writing the number "12" with a writing device; Figure 6B is a schematic diagram of the movement trajectory in Figure 6A, after applying the movement trajectory generation method of the present invention, the display module Fig. 7A is a schematic diagram of the movement trajectory of writing the number "86" with a writing device; and Fig. 7B is a schematic diagram of the movement trajectory displayed in Fig. 7A using the movement trajectory generating method of the present invention.