Non-contact motion recognition device and motion recognition method

Abstract

A contactless motion recognition device and motion recognition method capable of realizing contactless motion recognition with a simple structure. The contactless motion recognition device comprises: a plurality of mutually insulated detection electrodes arranged on a plane; a measuring unit for measuring the electrostatic capacitance between each detection electrode and an operation object; and a recognition unit for recognizing the motion of the operation object based on the measurement result of the measuring unit. The contactless motion recognition device is characterized in that the measuring unit measures the electrostatic capacitance of each detection electrode at a predetermined time interval, and the recognition unit determines the capacitance peak value of each detection electrode during the motion recognition period based on the measured electrostatic capacitance, and determines the order in which the operation object approaches or passes through the plurality of detection electrodes based on the measurement time point corresponding to the capacitance peak value of each detection electrode, thereby recognizing the motion of the operation object.

Description

Technical Field

[0001] The invention relates to a non-contact motion recognition device and a motion recognition method used in the non-contact motion recognition device. Background Art

[0002] Conventional 2D touch panels utilize electrostatic capacitance detection technology to detect the contact area and contact position of a finger on a plane, thereby recognizing gestures. However, such touch panels and gesture recognition processing cannot process gestures in three-dimensional space.

[0003] In addition, there are also electrostatic capacitive motion detection devices that can recognize gestures in three-dimensional space. In the electrostatic capacitive motion detection device in Patent Document 1, the gestures of the detected object are recognized by converting the output values ​​of the X-axis, Y-axis, and Z-axis of the sensor unit into the position information (trajectory information) of the detected object on the X-axis, Y-axis, and Z-axis, respectively.

[0004] Patent Document 1: Japanese Patent No. 5607335 Summary of the invention

[0005] However, when identifying gestures by calculating the position information (trajectory information) of the detected object in three-dimensional space, high measurement accuracy is required for each position information. The detection electrodes need to be switched through a switching mechanism to determine the position in the height direction (Z-axis direction), so the structure of the motion detection device becomes complicated.

[0006] The present invention provides a non-contact motion recognition device capable of realizing motion recognition with a simple structure and a motion recognition method used in the non-contact motion recognition device.

[0007] The contactless motion recognition device of the present invention comprises: a plurality of mutually insulated detection electrodes arranged on a plane; a measuring unit for measuring the electrostatic capacitance between each of the detection electrodes and an operation object; and an identification unit for identifying the action of the operation object based on the measurement result of the measuring unit. The contactless motion recognition device is characterized in that the measuring unit measures the electrostatic capacitance of each of the detection electrodes at a prescribed time interval, the identification unit determines the capacitance peak value of each of the detection electrodes during the motion recognition period based on the measured electrostatic capacitance, and determines the order in which the operation object approaches or passes through the plurality of detection electrodes based on the measurement time point corresponding to the capacitance peak value of each of the detection electrodes, thereby identifying the action of the operation object.

[0008] The action recognition method in the contactless action recognition device of the present invention, the contactless action recognition device comprises: a plurality of mutually insulated detection electrodes arranged on a plane; a measuring unit for measuring the electrostatic capacitance between each of the detection electrodes and an operation object; and a recognition unit for recognizing the action of the operation object based on the measurement result of the measuring unit. The action recognition method is characterized in that it includes: the step of the measuring unit measuring the electrostatic capacitance of each of the detection electrodes at a prescribed time interval, the recognition unit judging the capacitance peak value of each of the detection electrodes during the action recognition period based on the measured electrostatic capacitance, and determining the order in which the operation object approaches or passes through the plurality of detection electrodes based on the measurement time point corresponding to the capacitance peak value of each of the detection electrodes, and recognizing the action of the operation object.

[0009] According to the above-mentioned non-contact motion recognition device and motion recognition method, the motion (gesture) of the operating object in three-dimensional space is recognized by using the measurement time point of the capacitance peak of each detection electrode, and non-contact motion recognition can be realized with a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a diagram showing the structure of the motion recognition device according to the first embodiment.

[0011] Figure 2 It is a diagram showing the structure of the recognition unit.

[0012] Figure 3 FIG. 1 schematically shows an example of extracting a plurality of capacitance peak candidates from an action recognition period and determining a capacitance peak.

[0013] Figure 4 This is a flowchart of the recognition process of the motion recognition device.

[0014] Figure 5 This is a schematic diagram of an example of a sliding motion performed by a user's hand.

[0015] Figure 6 : is a graph schematically showing the change in electrostatic capacitance measured during the left sliding operation.

[0016] Figure 7 This is a schematic diagram of an example of a user's hand making a circular motion.

[0017] Figure 8 This is a graph schematically showing changes in electrostatic capacitance measured during a circular motion.

[0018] Fig. 9 This is another graph schematically showing the change in electrostatic capacitance measured during a circular motion.

[0019] Fig.10 This is a schematic diagram of an example of the user's hand performing up and down movements.

[0020] Fig.11 This is a graph schematically showing changes in electrostatic capacitance measured during up and down movements.

[0021] Fig.12 It is a diagram showing a recognition unit 40A according to the second embodiment. DETAILED DESCRIPTION

[0022] Next, embodiments of the contactless motion recognition device and the motion recognition method of the present invention are described.

[0023] (First Embodiment)

[0024] Figure 1 : is a diagram showing the action recognition device 100 of the first embodiment. Below, the XYZ coordinate system is defined for explanation. Among them, for the convenience of explanation, the -Z direction side is called the "lower side" or "lower", the +Z direction side is called the "upper side" or "upper", the -X direction side is called the "left side" or "left", the +X direction side is called the "right side" or "right", the -Y direction side is called the "rear side" or "rear", and the +Y direction side is called the "front side" or "front". However, the above-mentioned up and down, left and right, front and back do not represent the general up and down, left and right, front and back relationships. In addition, the state of observing the XY plane from the +Z direction side is called a top-down state.

[0025] The motion recognition device 100 includes a wiring board 10, a detection electrode 20 composed of a first detection electrode 20a to a fourth detection electrode 20d, a measuring unit 30, a recognition unit 40, and a storage unit 50. The motion here refers to the user of the motion recognition device 100 inputting a command to the motion recognition device 100 through a gesture or the like without touching the detection electrode 20. In addition, when the first to fourth detection electrodes 20a to 20d are not particularly distinguished, they are simply referred to as the detection electrodes 20.

[0026] The wiring board 10 is a sheet of an insulating system having a rectangular shape when viewed from above. In addition, the wiring board 10 may not be a rectangular shape when viewed from above. In the case of not being a rectangular shape, as long as it has Figure 1 The rectangular region shown as wiring board 10 may be used.

[0027] The detection electrode 20 is made of a metal material such as copper or aluminum, and is formed on the upper surface of the wiring board 10. In order to detect the movement in the +X direction (right direction), the -X direction (left direction), the +Y direction (front direction), and the -Y direction (backward direction), the first to fourth detection electrodes 20a to 20d are respectively arranged on the inner side of the four sides of the wiring board 10. The first detection electrode 20a is located on the inner side of the side on the +X direction side of the wiring board 10, the second detection electrode 20b is located on the inner side of the side on the -Y direction side of the wiring board 10, the third detection electrode 20c is located on the inner side of the side on the -X direction side of the wiring board 10, and the fourth detection electrode 20d is located on the inner side of the side on the +Y direction side of the wiring board 10. The first to fourth detection electrodes 20a to 20d are sequentially arranged clockwise along the four sides of the wiring board 10.

[0028] The first to fourth detection electrodes 20a to 20d are an example of a plurality of electrodes arranged in parallel on the wiring board 10. Specifically, the first detection electrode 20a and the third detection electrode 20c are opposite to each other and parallel. The first detection electrode 20a and the third detection electrode 20c are at the same position in the Y direction and have equal sizes. The second detection electrode 20b and the fourth detection electrode 20d are opposite to each other and parallel. The second detection electrode 20b and the fourth detection electrode 20d are at the same position in the X direction and have equal sizes. The first detection electrode 20a and the third detection electrode 20c are rectangular electrodes having long sides in the Y-axis direction. The second detection electrode 20b and the fourth detection electrode 20d are rectangular electrodes having long sides in the X-axis direction.

[0029] In this embodiment, the measuring unit 30 measures the electrostatic capacitance generated between the first to fourth detection electrodes 20a~20d and the user's hand by self-capacitance. In the motion recognition device 100, the recognition unit 40 recognizes the user's hand movement based on the electrostatic capacitance measured for the first to fourth detection electrodes 20a~20d at a predetermined time interval. Here, the user's hand is an example of an operation object, but the operation object is not limited to the user's hand, and can also be a leg, a foot, or a conductive object held by the user (such as a metal rod).

[0030] The measuring unit 30 , the identifying unit 40 , and the storage unit 50 may be realized by a computer including, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input / output interface, and an internal bus.

[0031] In other words, the measuring unit 30 and the identifying unit 40 are functional modules implemented by a computer executing a corresponding program. Alternatively, the measuring unit 30 may be a known circuit that detects the approach of a hand by utilizing a change in the electrostatic capacitance of the detecting electrode 20 .

[0032] Since electrostatic capacitance cannot be measured directly, current and voltage are usually measured to calculate electrostatic capacitance. When the four measured values ​​measured by the first to fourth detection electrodes 20a to 20d are less than the predetermined detection threshold, the measuring unit 30 calculates the average value of the measured values ​​obtained by multiple measurements in time series for the first to fourth detection electrodes 20a to 20d, and then the measuring unit 30 sets the calculated average value as the reference value when measuring electrostatic capacitance of the first to fourth detection electrodes 20a to 20d. This reference value is used to eliminate the influence of noise, etc.

[0033] The detection threshold is the upper limit of the reference value measured when the user's hand is not approaching, and is a threshold for determining whether the user's hand is approaching, and is preset and stored in the storage unit 50. Regarding the first to fourth detection electrodes 20a to 20d, the detection threshold may be a common value or a value set separately for the first to fourth detection electrodes 20a to 20d.

[0034] Furthermore, when the measuring unit 30 obtains each measured value of the first to fourth detection electrodes 20a to 20d, the value obtained by subtracting the reference value from the obtained measured value is used as each electrostatic capacitance Ca, Cb, Cc, Cd of the first to fourth detection electrodes 20a to 20d. In other words, each electrostatic capacitance Ca, Cb, Cc, Cd is the amount of change of the detected value relative to the reference value.

[0035] The recognition unit 40 determines the capacitance peak value of each detection electrode 20 during the motion recognition period based on the electrostatic capacitance Ca, Cb, Cc, and Cd obtained from the measurement unit 30, and determines the order in which the user's hand approaches or passes through the first to fourth detection electrodes 20a to 20d based on the measurement time points Ta, Tb, Tc, and Td corresponding to the capacitance peak value of each detection electrode 20, thereby recognizing the hand motion. The conditions for the recognition unit 40 to recognize the motion and the specific recognition method will be described later.

[0036] The storage unit 50 stores programs and data executed by the computer. Therefore, the capacitances Ca, Cb, Cc, and Cd obtained by the measuring unit 30 and the actions (types) recognized by the recognition unit 40 are also stored in the storage unit 50 .

[0037] Figure 2 4 is a diagram showing the structure of the recognition unit 40. Figure 2As shown, the recognition unit 40 includes a motion recognition period recognition unit 41 , a peak recognition unit 42 , and a motion validity confirmation unit 43 .

[0038] When at least one of the electrostatic capacitances Ca, Cb, Cc, and Cd obtained by the measuring unit 30 is greater than the first threshold TH1, the motion recognition period recognition unit 41 recognizes that the motion recognition period has started. The motion recognition period is the target period for the recognition unit 40 to perform subsequent recognition processing. Among them, the first threshold TH1 is a threshold for judging that the hand is close to the detection electrode 20 and the motion recognition can be started, which is pre-set and stored in the storage unit 50. The first threshold TH1 is a value greater than the pre-set detection threshold.

[0039] When the electrostatic capacitances Ca, Cb, Cc, and Cd obtained by the measuring unit 30 are all less than the second threshold TH2, the action recognition period recognition unit 41 recognizes that the action recognition period is over. The second threshold TH2 is less than or equal to the first threshold TH1. When the electrostatic capacitances Ca, Cb, Cc, and Cd are all less than the second threshold TH2, it means that the hand has moved away from the first to fourth detection electrodes 20a to 20d to a certain extent.

[0040] In addition, in an environment with a lot of noise, it is preferred to set the second threshold TH2 used to determine the end of the motion recognition period to be smaller than the first threshold TH1 used to determine the start of the motion recognition period. This can prevent the motion recognition period from being terminated prematurely due to noise, thereby more reliably suppressing false detection.

[0041] The action recognition period recognition unit 41 determines the target period for the recognition unit 40 to perform recognition processing, thereby preventing the recognition unit 40 from performing unnecessary recognition processing when the operating object such as a hand is far from the detection electrode 20 .

[0042] The peak identification unit 42 extracts one or more capacitance peak candidates from the motion recognition period for each detection electrode 20 , and identifies the maximum value among the capacitance peak candidates as the capacitance peak in the motion recognition period.

[0043] Here, the candidate capacitance peak is the maximum value among the continuous 2N+1 electrostatic capacitors, and the maximum value is greater than the N electrostatic capacitors before the maximum value and the N electrostatic capacitors after the maximum value among the 2N+1 electrostatic capacitors, where N is a natural number preset greater than or equal to 2. In other words, the candidate capacitance peak is the electrostatic capacitor at the center position among the continuous odd-numbered electrostatic capacitors, and the electrostatic capacitor at the center position is greater than the other electrostatic capacitors among the odd-numbered electrostatic capacitors.

[0044] In addition, the candidate electrostatic capacitance peak value may be an electrostatic capacitance located at a substantially central position among a continuous even number of electrostatic capacitances, and the electrostatic capacitance at the substantially central position may be larger than other electrostatic capacitances among the even number of electrostatic capacitances.

[0045] Since N is a natural number that is preset to be greater than or equal to 2, the selection of the candidate capacitance peak is performed by selecting the peak at the central position from more than 5 consecutive electrostatic capacitors. In this way, some small peaks can be automatically filtered out, thereby reducing the amount of calculation for peak recognition. Moreover, by adjusting the set value of N, the peak filtering capability and the amount of calculation can be flexibly adjusted as needed.

[0046] Figure 3 FIG. 1 schematically shows an example of extracting a plurality of capacitance peak candidates from an action recognition period and determining a capacitance peak.

[0047] exist Figure 3 In the example shown, the horizontal axis represents time T, and the vertical axis represents the electrostatic capacitance C measured for a certain detection electrode 20. Figure 3 In FIG. 1 , there is no regulation on the units of time T and electrostatic capacitance C, and they represent arbitrary units (au).

[0048] exist Figure 3 , assuming that the period from T6 to T20 (the period between the two dotted lines in the figure) is an action recognition period determined by the action recognition period recognition unit 41, and during the action recognition period, a total of 15 electrostatic capacitances C6~C20 are measured, which are C6=15, C7=17, C8=20, C9=24, C10=19, C11=16, C12=17, C13=18, C14=14, C15=16, C16=17, C17=19, C18=16, C19=15, and C20=13 respectively.

[0049] Here, the candidate capacitance peak is defined as the case where N = 3. In this case, the condition for becoming a candidate capacitance peak is: the maximum value among 7 consecutive electrostatic capacitances, and the maximum value is greater than the 3 electrostatic capacitances before the maximum value and the 3 electrostatic capacitances after the maximum value among the 7 electrostatic capacitances.

[0050] based on Figure 3It can be seen that there are three protruding peak points T9, T13 and T17 between T6 and T20. Since C9>C6~C8 and C9>C5~C7, electrostatic capacitance C9 (=24) becomes a candidate capacitance peak. In addition, since C17>C14~C16 and C17>C18~C20, electrostatic capacitance C17 (=19) also becomes a candidate capacitance peak. However, since C13<C10, electrostatic capacitance C13 (=18) does not meet the conditions to become a candidate capacitance peak. In other words, according to the above-mentioned candidate capacitance peak conditions when N=3, the small peak at T13 is automatically filtered out in the step of determining whether it is a candidate capacitance peak, which can reduce the amount of computation required for subsequent peak recognition processing.

[0051] Thus, the peak identifying unit 42 Figure 3 During the action recognition period, two candidate capacitance peaks C9 (=24) and C17 (=19) are extracted, and the maximum value of these two candidate capacitance peaks, namely C9, is determined as the capacitance peak during the action recognition period.

[0052] Back to Figure 2 The action validity confirmation unit 43 determines the validity of the action recognition period according to at least one of the number of detection electrodes 20 that recognize the capacitance peak during the action recognition period and the time length of the action recognition period. By confirming the validity of the action during the action recognition period by the action validity confirmation unit 43, some noise or obviously invalid actions can be removed before recognizing the action according to the detection time point of the capacitance peak, thereby improving the efficiency and accuracy of the recognition process. The action timing of the action validity confirmation unit will be explained in the recognition process later.

[0053] In the case where the validity is determined based on the number of detection electrodes 20 that recognize the capacitance peak, when the number of detection electrodes 20 that recognize the capacitance peak during the action recognition period is greater than or equal to 2, the action validity confirmation unit 43 determines that the action recognition period is valid. In this embodiment, the minimum number of detection electrodes 20 that recognize the capacitance peak during the action recognition period is 2. If the number of detection electrodes 20 that recognize the capacitance peak is less than 2, the action is noise or an obviously invalid action, and the recognition unit 40 does not perform subsequent recognition processing.

[0054] In addition, when the validity is determined based on the length of time during the action recognition period, when the length of time during the action recognition period is less than or equal to the maximum recognition time, the action validity confirmation unit 43 determines that the action recognition period is valid. The maximum recognition time is pre-set based on the maximum possible time of the action of the operation object. If the action recognition period of a certain action exceeds the maximum recognition time, the action is noise or an obviously invalid action, and the recognition unit 40 does not perform subsequent recognition processing.

[0055] Figure 4 4 is a flowchart of the recognition process of the motion recognition device 100 .

[0056] First, when one or more of the measurement values ​​measured by the first to fourth detection electrodes 20a to 20d are greater than or equal to the detection threshold, the detection is started. Figure 4 Identification processing in .

[0057] The measuring unit 30 calculates the capacitances Ca to Cd at predetermined time intervals (step S1 ). The capacitances Ca to Cd are stored in the storage unit 50 .

[0058] The action recognition period recognition unit 41 of the recognition unit 40 determines whether or not any one of the capacitances Ca to Cd calculated in step S1 is larger than the first threshold value TH1 (step S2 ).

[0059] When any one of the capacitances Ca to Cd calculated in step S1 is larger than the first threshold TH1 ( S2 : Yes), the motion recognition period recognition unit 41 determines that the motion recognition period has started (step S3 ).

[0060] Then, the measuring unit 30 continues to calculate the capacitances Ca to Cd at predetermined time intervals (step S4). During the motion recognition period, the recognition unit 41 determines whether all the capacitances Ca to Cd calculated in step S4 are smaller than the second threshold value TH2 (step S5).

[0061] When all of the capacitances Ca to Cd calculated in step S4 are smaller than the second threshold value TH2 ( S5 : Yes), the motion recognition period recognition unit 41 determines that the motion recognition period has ended (step S6 ).

[0062] Next, the peak recognition unit 42 recognizes the capacitance peak values ​​of the first to fourth detection electrodes 20a to 20d during the action recognition period for each detection electrode 20, and stores the recognized capacitance peak values ​​in the storage unit 50 (step S7). The recognition of the candidate capacitance peak values ​​can be performed in step S7 or between steps S3 to S6.

[0063] Then, the motion validity confirmation unit 43 determines the validity of the motion recognition period (step S8 ).

[0064] When it is judged to be valid in step S8 (step S8: yes), the recognition unit 40 recognizes the hand movement during the motion recognition period based on the measurement time points Ta, Tb, Tc, Td corresponding to the capacitance peak of each detection electrode 20 and the predetermined motion recognition conditions (step S9).

[0065] Through steps S1 to S9 , a series of processing related to action recognition is completed.

[0066] Below, we take the sliding action and circle action of the user's hand as an example to Figure 4 The processing of step S8 will be described in detail.

[0067] Figure 5 is a schematic diagram of an example of a user's hand performing a sliding action. As an example of a sliding action, as shown by the dotted arrow, Figure 5 , the hand slides from the first detection electrode 20a to the third detection electrode 20c in the space above the detection electrode 20, i.e., the leftward sliding action of sliding the hand to the left. In addition, although not shown in the figure, the sliding action at least includes the rightward sliding action of the hand sliding from the third detection electrode 20c to the first detection electrode 20a, the backward sliding action of the hand sliding from the fourth detection electrode 20d to the second detection electrode 20b, and the forward sliding action of the hand sliding from the second detection electrode 20b to the fourth detection electrode 20d.

[0068] Figure 6 : is a graph schematically showing the changes in the electrostatic capacitances Ca, Cb, Cc, and Cd measured during the left sliding operation. The horizontal axis represents time T, and the vertical axis represents the electrostatic capacitances C measured for the first to fourth detection electrodes 20a to 20d, respectively. Figure 6 In FIG. 1 , there is no regulation on the units of time T and electrostatic capacitance C, and they represent arbitrary units (au).

[0069] When the hand performs a left sliding action from the first detection electrode 20a side toward the third detection electrode 20c side, as shown in FIG. Figure 6 As shown, the measurement time points Ta to Td corresponding to the capacitance peaks of the first to fourth detection electrodes 20a to 20d during the motion recognition period are in the order of the first detection electrode 20a, the fourth detection electrode 20d, the second detection electrode 20b, and the third detection electrode 20c.

[0070] Here, the first electrode to detect the capacitance peak is the first detection electrode 20a located near the starting point (right side) of the left sliding action, and the last electrode to detect the capacitance peak is the third detection electrode 20c located near the end point (left side) of the left sliding action. The fourth detection electrode 20d and the second detection electrode 20b are two electrodes passed during the left sliding action.

[0071] In addition, the peak order for identifying the left sliding action is not limited to the above order, and the order of the fourth detection electrode 20d and the second detection electrode 20b in the above order can be interchanged. That is, the measurement time points Ta to Td corresponding to the capacitance peaks of the first to fourth detection electrodes 20a to 20d during the action recognition period can also be the order of the first detection electrode 20a, the second detection electrode 20b, the fourth detection electrode 20d, and the third detection electrode 20c.

[0072] Moreover, even if the capacitance peak of the fourth detection electrode 20d or the second detection electrode 20b is not detected during the action recognition period, the left-slide action can be recognized. In the case where the capacitance peak of the second detection electrode 20b is not detected, if the measurement time points Ta, Td, and Tc corresponding to the capacitance peaks of the three detection electrodes detected are in the order of the first detection electrode 20a, the fourth detection electrode 20d, and the third detection electrode 20c, it can also be recognized as a left-slide action. In the case where the capacitance peak of the fourth detection electrode 20d is not detected, if the measurement time points Ta, Tb, and Tc corresponding to the capacitance peaks of the three detection electrodes detected are in the order of the first detection electrode 20a, the second detection electrode 20b, and the third detection electrode 20c, it can also be recognized as a left-slide action.

[0073] In addition, the number of detection electrodes 20 is not limited to four, and the plurality of detection electrodes 20 may also be composed of more than four detection electrodes that form a rectangle or a ring. When the capacitance peaks detected during the action recognition period include more than three and the detection electrode 20 corresponding to the first capacitance peak during the action recognition period and the detection electrode 20 corresponding to the last capacitance peak are located at symmetrical positions relative to the center of the rectangle or the ring, the recognition unit 40 recognizes the action of the operation object as a sliding action from the side of the detection electrode 20 corresponding to the first capacitance peak toward the side of the detection electrode 20 corresponding to the last capacitance peak.

[0074] Through the above-mentioned recognition method, there is no need for complex processing such as calculating the action trajectory. The sliding action can be recognized by simply judging the order of the measurement time points corresponding to the capacitance peak values ​​of each detection electrode 20. The logic of the recognition process is simple and the recognition accuracy is high.

[0075] Figure 7 is a schematic diagram of an example of a user's hand making a circular motion. As an example of a circular motion, as shown by the dotted arrow, Figure 7 The figure shows the hand making a clockwise circular motion starting from the first detection electrode 20a in the space above the detection electrode 20. In addition, although not shown in the figure, the circular motion also includes the hand making a clockwise circular motion starting from other detection electrodes other than the first detection electrode 20a and the hand making a counterclockwise circular motion starting from any detection electrode.

[0076] Figure 8 Graphs schematically show changes in electrostatic capacitances Ca, Cb, Cc, and Cd measured during a circular motion.

[0077] When the hand makes a clockwise circular motion starting from the first detection electrode 20a, as shown in FIG. Figure 8 As shown, the measurement time points Ta to Td corresponding to the capacitance peaks of the first to fourth detection electrodes 20a to 20d during the action recognition period are in the order of the first detection electrode 20a, the second detection electrode 20b, the third detection electrode 20c, and the fourth detection electrode 20d.

[0078] Here, the first electrode to detect the capacitance peak is the first detection electrode 20a located near the starting point (left side) of the circle drawing motion, and the last electrode to detect the capacitance peak is the fourth detection electrode 20d located near the end point (front side) of the circle drawing motion.

[0079] Although not shown in the figure, when the hand makes a counterclockwise circular motion starting from the first detection electrode 20a, the measurement time points Ta~Td corresponding to the capacitance peaks of the first detection electrode 20a to the fourth detection electrode 20d during the motion recognition period become the order of the first detection electrode 20a, the fourth detection electrode 20d, the third detection electrode 20c, and the second detection electrode 20b.

[0080] In addition, although not shown in the figure, in a case where the multiple detection electrodes 20 are composed of four or more detection electrodes that form a rectangle or a ring and the four or more detection electrodes are arranged in a clockwise direction, when the number of detection electrodes that detect the capacitance peak during the motion recognition period is more than three quarters of the total number of the multiple detection electrodes 20, and the positions of the detection electrodes 20 that detect the capacitance peak in the plane are arranged in a clockwise direction, the recognition unit 40 recognizes the motion of the operation object as a clockwise circle motion, and when the number of detection electrodes that detect the capacitance peak during the motion recognition period is more than three quarters of the total number of the multiple detection electrodes 20, and the positions of the detection electrodes 20 that detect the capacitance peak in the plane are arranged in a counterclockwise direction, the recognition unit 40 recognizes the motion of the operation object as a counterclockwise circle motion.

[0081] In addition, the recognition accuracy of the circle drawing action can be further improved by increasing the number of capacitance peaks during the action recognition period.

[0082] For example, when the hand makes a circular motion, the starting point and the end point of the circular motion usually coincide with each other, and the hand will pass through the position near the starting point of the circular motion twice. Fig. 9As shown, there are 5 capacitance peaks identified during the action recognition period, and the measurement time points Ta~Td corresponding to the capacitance peaks of the first detection electrode 20a to the fourth detection electrode 20d during the action recognition period are in the order of the first detection electrode 20a, the second detection electrode 20b, the third detection electrode 20c, the fourth detection electrode 20d, and the first detection electrode 20a.

[0083] In addition, although not shown in the figure, in the case where the multiple detection electrodes 20 are composed of four or more detection electrodes that form a rectangle or a ring and the four or more detection electrodes 20 are arranged in clockwise order, when the number of detection electrodes that detect the capacitance peak during the action recognition period is more than three quarters of the total number of the multiple detection electrodes 20, and the positions of the detection electrodes that detect the capacitance peak in the plane are arranged in clockwise order, and the detection electrode 20 corresponding to the first capacitance peak during the action recognition period and the detection electrode 20 corresponding to the last capacitance peak are the same detection electrode, the recognition unit 40 recognizes the action of the operation object as a clockwise circle drawing action, and when the number of detection electrodes that detect the capacitance peak during the action recognition period is more than three quarters of the total number of the multiple detection electrodes 20, and the positions of the detection electrodes 20 that detect the capacitance peak in the plane are arranged in counterclockwise order, and the detection electrode 20 corresponding to the first capacitance peak during the action recognition period and the detection electrode 20 corresponding to the last capacitance peak are the same detection electrode, the recognition unit 40 recognizes the action of the operation object as a counterclockwise circle drawing action.

[0084] In addition, in order to further improve the recognition accuracy of the circle action, it is also possible to consider further increasing the number of capacitance peaks used to recognize the circle action. For example, although not shown in the figure, it is also possible to consider setting the number of capacitance peaks used to recognize the circle action to more than twice the total number of the plurality of detection electrodes 20. In this case, the circle action is recognized only after the hand has made two circles, thereby further preventing confusion with other actions.

[0085] Through the above-mentioned recognition method, there is no need for complex processing such as calculating the action trajectory. The clockwise or counterclockwise circle drawing action can be identified by simply judging the order of the measurement time points corresponding to the capacitance peak values ​​of each detection electrode 20. The logic of the recognition processing is simple and the recognition accuracy is high.

[0086] In addition, Figure 4 In step S8, only the identification of the sliding action or the circle drawing action can be performed, or the identification of the sliding action and the circle drawing action can be performed simultaneously or successively. In addition, in the above-mentioned step S8, the identification of the up and down actions can also be performed.

[0087] Fig.10Schematic diagram of an example of the up-and-down movement of the user's hand. As an example of the up-and-down movement of the user's hand relative to the plane where the first to fourth detection electrodes 20a to 20d are located, Fig.10 , the case where the up-and-down movement is performed in the orthogonal direction to the plane where the first to fourth detection electrodes 20a to 20d are located is shown. In addition, although not shown in the figure, the up-and-down movement may also include an inclined up-and-down movement with a certain angle to the orthogonal direction, and the certain angle of inclination here may be, for example, an inclination within 45 degrees.

[0088] Fig.11 Graphs schematically show changes in electrostatic capacitances Ca, Cb, Cc, and Cd measured during the up and down movements.

[0089] When the hand moves up and down relative to the plane where the first to fourth detection electrodes 20a to 20d are located, Fig.11 As shown, the number of detection electrodes 20 that identify capacitance peaks during action recognition is equal to 4 (ie, each detection electrode 20 detects a capacitance peak) and the maximum time difference between the capacitance peaks corresponding to the first to fourth detection electrodes 20a~20d respectively is less than the predetermined time difference.

[0090] The predetermined time difference here can be set to a fixed value, or can be set to different values ​​according to the speed of the action. The speed of the action is usually determined according to the maximum time difference between multiple capacitance peaks or the time difference between specific capacitance peaks.

[0091] and Figure 6 The sliding action and Figure 8 Compared with the case of the circle-drawing action in the hand, the time difference between the capacitance peaks corresponding to each detection electrode 20 is much smaller when performing the up and down action. By presetting the predetermined time difference in the storage unit 50, the up and down action of the hand can be easily identified.

[0092] In addition, although not shown in the figure, the multiple detection electrodes 20 can also be composed of more than four detection electrodes that form a rectangle or a ring. When the number of detection electrodes that detect capacitance peaks during the motion recognition period is more than three quarters of the total number of the multiple detection electrodes 20, and the maximum time difference between the identified multiple capacitance peaks is less than the predetermined time difference, the recognition unit 40 recognizes the motion of the operating object as an up and down motion relative to the plane where the four or more detection electrodes are located.

[0093] (Second Embodiment)

[0094] The second embodiment is a variation of the first embodiment, and the difference between the second embodiment and the first embodiment is that the recognition unit further includes a capacitance change rate calculation unit. The other structures of the motion recognition device are the same as those of the first embodiment, and only the differences are described below.

[0095] Fig.12 2 is a diagram showing a recognition unit 40A according to the second embodiment. The recognition unit 40A includes a capacitance change rate calculation unit 44 in addition to a motion recognition period recognition unit 41 , a peak value recognition unit 42 , and a motion validity confirmation unit 43 .

[0096] First, Figure 6 The method of calculating the capacitance change rate by the capacitance change rate calculation unit 44 will be described by taking one measurement time point Tc as an example.

[0097] Figure 6 The measurement time point Tc in is the measurement time point corresponding to the capacitance peak of the third detection electrode 20c during the action recognition period, and the capacitance change rate R corresponding to the first to fourth detection electrodes 20a~20d at the measurement time point Tc is calculated according to formula (1).

[0098] R=(C0-C1) / C0……(1)

[0099] Among them, C0 represents the electrostatic capacitance of a detection electrode at any measurement time point, C1 represents the electrostatic capacitance of the detection electrode at the measurement time point before the any measurement time point, and R represents the capacitance change rate corresponding to the detection electrode at the any measurement time point.

[0100] The capacitance change rate (i.e., the capacitance change rate corresponding to the first detection electrode 20a at the measurement time point Tc) Figure 6 The capacitance change rate at point A in the measurement is Rca, and the capacitance change rate corresponding to the second detection electrode 20b at the measurement time point Tc (i.e. Figure 6 The capacitance change rate at point B in the measurement is set as Rcb, and the capacitance change rate corresponding to the second detection electrode 20c at the measurement time point Tc (i.e. Figure 6 The capacitance change rate at point C in the measurement is set as Rcc, and the capacitance change rate corresponding to the second detection electrode 20d at the measurement time point Tc (i.e. Figure 6 When the capacitance change rate at point D in the measurement time Tc is set to Rcd, the capacitance change rate calculation unit 44 calculates the sum of the capacitance change rates corresponding to the first to fourth detection electrodes 20a to 20d at the measurement time point Tc as the cumulative capacitance change rate RC at the measurement time point Tc. That is, RC = Rca + Rcb + Rcc + Rcd.

[0101] Using the same method, the capacitance change rate calculation unit 44 can also calculate Figure 6 The accumulated capacitance change rates RA, RB, and RD at the measurement time points Ta, Tb, and Td in the above-mentioned process of calculating the capacitance change rate by the capacitance change rate calculation unit 44 can be Figure 4 The process is performed in step S7 or step S9.

[0102] Then, in Figure 4 In step S9, the recognition unit 40 further recognizes the hand motion based on the sum Rsum of the accumulated capacitance change rates at the measurement time points Ta to Td corresponding to the multiple capacitance peaks during the motion recognition period. Here, Rsum=RA+RB+RC+RD.

[0103] In the recognition of some actions whose peaks are close to each other, the accuracy of action recognition can be further improved by further using the sum of the accumulated capacitance change rates at multiple peaks.

[0104] Below, Fig.11 Taking the up and down actions shown in the figure as an example, the motion recognition processing using the capacitance change rate is described. Here, it is assumed that the number of detection electrodes 20 that recognize the capacitance peak is equal to 4, and the maximum time difference between the capacitance peaks corresponding to the first to fourth detection electrodes 20a to 20d is less than the predetermined time difference. In addition, it is assumed that the total value of the predetermined change rate pre-set in the storage unit 50 is 0.16.

[0105] The capacitance change rate calculation unit 44 calculates Fig.10 The accumulated capacitance change rates RA, RB, RC, RD and the sum Rsum of the accumulated capacitance change rates at multiple measurement time points Ta, Tb, Tc, Td.

[0106] RA=0.0285

[0107] RB=0.0285

[0108] RC=0.0268

[0109] RD=0.0180

[0110] Rsum=RA+RB+RC+RD=0.1018.

[0111] Since the sum Rsum (0.1018) of the accumulated capacitance change rates at multiple measurement time points Ta, Tb, Tc, and Td corresponding to multiple capacitance peaks is less than the predetermined total change rate value (0.16), the recognition unit 40 recognizes the hand movement as an up and down movement relative to the plane where the first to fourth detection electrodes 20a to 20d are located.

[0112] In addition, although not shown in the figure, the multiple detection electrodes 20 can also be composed of more than four detection electrodes that form a rectangle or a ring. When the number of detection electrodes that detect capacitance peaks during the action recognition period is more than three quarters of the total number of the multiple detection electrodes 20, and the maximum time difference between the identified multiple capacitance peaks is less than the predetermined time difference, and the sum of the accumulated capacitance change rates at multiple measurement time points corresponding to the multiple capacitance peaks is less than the predetermined change rate total value, the recognition unit 40 recognizes the action of the operation object as an up and down action relative to the plane where the four or more detection electrodes are located.

[0113] When identifying up and down actions, by further determining the sum Rsum of the accumulated capacitance change rates at the measurement time points Ta, Tb, Tc, and Td corresponding to the multiple capacitance peaks during the action recognition period, a portion of the fast sliding actions and the inclined up and down actions with a certain angle to the up and down direction can be filtered out, further improving the recognition accuracy of the up and down actions. This is because the accumulated capacitance change rate of the up and down actions is relatively smaller than that of the sliding actions and the inclined up and down actions.

[0114] In addition, according to the difference in the maximum time difference between the capacitance peaks corresponding to the first to fourth detection electrodes 20a~20d, the sum of the accumulated capacitance change rates at the multiple measurement time points Ta, Tb, Tc, and Td corresponding to the multiple capacitance peaks also has certain differences. Therefore, it is preferred to set different predetermined change rate total values ​​for the maximum time difference between different multiple capacitance peaks, so as to improve the accuracy of recognition. When the maximum time difference is within a certain range, the predetermined change rate total value is inversely proportional to the maximum time difference. The smaller the maximum time difference, the larger the corresponding predetermined change rate total value. Moreover, the setting of the predetermined change rate total value is directly related to the sampling period. For example, when the sampling period is 7ms, when the maximum time difference between the multiple capacitance peaks is less than 7ms, the predetermined change rate total value is set to 0.4, and when the maximum time difference between the multiple capacitance peaks is greater than 7ms and less than 28ms, the predetermined change rate total value is set to 0.16.

[0115] (Other Modifications)

[0116] The present invention is not limited to the above-mentioned embodiments. That is, those skilled in the art can also make various changes, combinations, and substitutions to the constituent elements of the above-mentioned embodiments within the technical scope of the present invention or its equivalent scope.

[0117] For example, the above-mentioned embodiments show a case where the plurality of detection electrodes are composed of four detection electrodes forming a rectangle. In fact, the plurality of detection electrodes may be composed of four detection electrodes forming a ring or other convex polygon.

[0118] In addition, the multiple detection electrodes may also be composed of three detection electrodes that form a convex polygon or a ring. In this case, when the order of the measurement time points corresponding to the capacitance peaks of the three detection electrodes during the action recognition period is consistent with the order in which the three detection electrodes are arranged in a clockwise direction, the recognition unit recognizes the action of the operation object as a clockwise circle action, and when the order of the measurement time points corresponding to the capacitance peaks of the three detection electrodes during the action recognition period is consistent with the order in which the three detection electrodes are arranged in a counterclockwise direction, the recognition unit recognizes the action of the operation object as a counterclockwise circle action.

[0119] In addition, the multiple detection electrodes can also be composed of more than four detection electrodes that form a convex polygon, and each side of the convex polygon corresponds to one of the detection electrodes. In this case, when the number of detection electrodes that detect the capacitance peak during the action recognition period is more than three quarters of the total number of the multiple detection electrodes, and the positions of the detection electrodes that detect the capacitance peak in the plane are arranged clockwise in sequence, the recognition unit recognizes the action of the operation object as a clockwise circle action. When the number of detection electrodes that detect the capacitance peak during the action recognition period is more than three quarters of the total number of the multiple detection electrodes, and the positions of the detection electrodes that detect the capacitance peak in the plane are arranged counterclockwise in sequence, the recognition unit recognizes the action of the operation object as a counterclockwise circle action.

[0120] In addition, in the process of identifying up and down movements, the judgment condition that the maximum time difference between the capacitance peaks corresponding to the multiple detection electrodes is less than the predetermined time difference is used. This judgment condition is not limited to the judgment of up and down movements, but can also be used to judge other movements such as sliding movements. For example, when judging the left sliding movement, in addition to judging the order in which the hand approaches or passes through the multiple detection electrodes, it can also be judged whether the maximum time difference between the capacitance peaks corresponding to the multiple detection electrodes is less than the predetermined time difference corresponding to the sliding movement. The predetermined time difference corresponding to the sliding movement is set to 14ms, for example, so that some irregular movements, such as excessively fast sliding movements, can be filtered out.

[0121] In addition, the reference value used in measuring the electrostatic capacitance can also be updated when all the electrostatic capacitances measured by the measuring unit are less than the detection threshold. Specifically, when all the electrostatic capacitances measured by the measuring unit are less than the detection threshold, the average value of the values ​​measured multiple times by the measuring unit is calculated for each detection electrode, and the average value for each detection electrode is used as the reference value when the measuring unit measures the electrostatic capacitance of each detection electrode. When all the electrostatic capacitances measured by the measuring unit are less than the detection threshold, the electrostatic capacitances obtained from each detection electrode will change according to changes in temperature, the surrounding environment, etc., so by updating the reference value, the electrostatic capacitance can be measured with higher accuracy.

Claims

1. A contactless motion recognition device, comprising: a plurality of mutually insulated detection electrodes arranged on a plane; a measuring unit for measuring the electrostatic capacitance between each of the detection electrodes and an operation object; and a recognition unit for recognizing the motion of the operation object based on the measurement result of the measuring unit, wherein the contactless motion recognition device is characterized in that: The measuring unit measures the electrostatic capacitance of each of the detection electrodes at predetermined time intervals. The recognition unit determines the capacitance peak value of each detection electrode during the action recognition period according to the measured electrostatic capacitance, and determines the order in which the operation object approaches or passes through the plurality of detection electrodes based on the measurement time point corresponding to the capacitance peak value of each detection electrode, and recognizes the action of the operation object. The plurality of detection electrodes are composed of four or more detection electrodes that are arranged in a rectangular or ring shape. When the number of detection electrodes detecting capacitance peaks during the action recognition period is more than three quarters of the total number of the plurality of detection electrodes, and the maximum time difference between the recognized plurality of capacitance peaks is less than a predetermined time difference, and the sum of the accumulated capacitance change rates at the plurality of measurement time points corresponding to the plurality of capacitance peaks is less than a predetermined change rate total value, the recognition unit recognizes the action of the operation object as an up and down action relative to the plane where the four or more detection electrodes are located, The identification unit further includes a capacitance change rate calculation unit, The capacitance change rate calculation unit calculates a plurality of capacitance change rates R corresponding to a plurality of detection electrodes at each measurement time point according to formula (1) for each measurement time point corresponding to the capacitance peak value detected during the action recognition period, and uses the sum of the plurality of capacitance change rates R as the accumulated capacitance change rate at the measurement time point. R=(C0-C1) / C0……(1), in, C0 represents the electrostatic capacitance of a detection electrode at any measurement time point, C1 represents the electrostatic capacitance of the detection electrode at a measurement time point before the measurement time point, and R represents the capacitance change rate corresponding to the detection electrode at the measurement time point.

2. The contactless motion recognition device according to claim 1, characterized in that: The recognition unit further includes a motion recognition period recognition unit. When the electrostatic capacitance of one of the plurality of detection electrodes is greater than a first threshold, the motion recognition period recognition unit recognizes that the motion recognition period has started. When the electrostatic capacitance of all the detection electrodes among the plurality of detection electrodes is smaller than a second threshold, the motion recognition period recognition unit recognizes that the motion recognition period is ended and the second threshold is smaller than the first threshold.

3. The non-contact motion recognition device according to claim 1, characterized in that: The recognition unit further includes a peak recognition unit, which extracts one or more candidate capacitance peaks from the action recognition period for each of the detection electrodes and recognizes a maximum value among the candidate capacitance peaks as a capacitance peak in the action recognition period. The candidate capacitance peak is the maximum value among the consecutive 2N+1 electrostatic capacitors, and the maximum value is greater than the N electrostatic capacitors before the maximum value and the N electrostatic capacitors after the maximum value among the 2N+1 electrostatic capacitors, where N is a pre-set natural number greater than or equal to 2.

4. The non-contact motion recognition device according to claim 1, characterized in that: The recognition unit further includes an action validity confirmation unit that determines the validity of the action recognition period based on at least one of the number of detection electrodes that recognize capacitance peaks during the action recognition period and the time length of the action recognition period.

5. The contactless motion recognition device according to claim 4, characterized in that: In the case where the validity is determined based on the number of detection electrodes that recognize the capacitance peak, when the number of detection electrodes that recognize the capacitance peak during the action recognition period is greater than or equal to 2, the action validity confirmation unit determines that the action recognition period is valid. When the validity is determined based on the time length of the motion recognition period, when the time length of the motion recognition period is less than or equal to the maximum recognition time, the motion validity confirmation unit determines that the motion recognition period is valid.

6. The non-contact motion recognition device according to claim 1, characterized in that: The plurality of detection electrodes are composed of four or more detection electrodes that are arranged in a rectangular or ring shape. When the capacitance peaks detected during the action recognition period include more than three and the detection electrode corresponding to the first capacitance peak during the action recognition period and the detection electrode corresponding to the last capacitance peak are located at symmetrical positions relative to the center of the rectangle or the ring, the recognition unit recognizes the action of the operation object as a sliding action from the side of the detection electrode corresponding to the first capacitance peak toward the side of the detection electrode corresponding to the last capacitance peak.

7. The contactless motion recognition device according to claim 1, characterized in that: In the case where the plurality of detection electrodes are composed of four detection electrodes in a rectangular or ring shape, the four detection electrodes are sequentially arranged clockwise as first to fourth detection electrodes, When the measurement time points corresponding to the capacitance peaks of the first detection electrode to the fourth detection electrode during the action recognition period are in the order of the first detection electrode, the second detection electrode, or / and the fourth detection electrode, and the third detection electrode, the recognition unit recognizes the action of the operation object as a sliding action from the side of the first detection electrode toward the side of the third detection electrode.

8. The non-contact motion recognition device according to claim 1, characterized in that: The plurality of detection electrodes are composed of four or more detection electrodes that are arranged in a rectangular or ring shape, and the four or more detection electrodes are arranged in sequence in a clockwise direction. When the number of detection electrodes that detect capacitance peaks during the action recognition period is more than three quarters of the total number of the plurality of detection electrodes, and the detection electrodes that detect capacitance peaks are arranged in sequence clockwise in the plane, the recognition unit recognizes the action of the operation object as a clockwise circle action, When the number of detection electrodes that detect capacitance peaks during the action recognition period is more than three quarters of the total number of the multiple detection electrodes, and the positions of the detection electrodes that detect capacitance peaks in the plane are arranged counterclockwise in sequence, the recognition unit recognizes the action of the operation object as a counterclockwise circle action.

9. The non-contact motion recognition device according to claim 1, characterized in that: The plurality of detection electrodes are composed of four detection electrodes in a rectangular or ring shape, and the four detection electrodes are sequentially arranged as a first detection electrode to a fourth detection electrode in a clockwise direction. In a case where the measurement time points corresponding to the capacitance peaks of the first detection electrode to the fourth detection electrode during the action recognition period include at least the first detection electrode, the second detection electrode, the third detection electrode, and the fourth detection electrode in the order of the first detection electrode, the recognition unit recognizes the action of the operation object as a clockwise circle action starting from the first detection electrode, When the measurement time points corresponding to the capacitance peaks of the first detection electrode to the fourth detection electrode during the action recognition period include at least the order of the first detection electrode, the fourth detection electrode, the third detection electrode, and the second detection electrode, the recognition unit recognizes the action of the operation object as a counterclockwise circle action starting from the first detection electrode.

10. A method for motion recognition in a contactless motion recognition device, the contactless motion recognition device comprising: a plurality of mutually insulated detection electrodes arranged on a plane; a measuring unit for measuring the electrostatic capacitance between each of the detection electrodes and an operation object; and a recognition unit for recognizing the motion of the operation object based on the measurement result of the measuring unit, wherein the method comprises: The measuring unit measures the electrostatic capacitance of each of the detection electrodes at predetermined time intervals, The recognition unit determines the capacitance peak value of each detection electrode during the action recognition period according to the measured electrostatic capacitance, and determines the order in which the operation object approaches or passes through the plurality of detection electrodes based on the measurement time point corresponding to the capacitance peak value of each detection electrode, and recognizes the action of the operation object. The plurality of detection electrodes are composed of four or more detection electrodes that are arranged in a rectangular or ring shape. In the step of identifying the action of the operation object, When the number of detection electrodes detecting capacitance peaks during the action recognition period is more than three quarters of the total number of the plurality of detection electrodes, and the maximum time difference between the recognized plurality of capacitance peaks is less than a predetermined time difference, and the sum of the accumulated capacitance change rates at the plurality of measurement time points corresponding to the plurality of capacitance peaks is less than a predetermined change rate total value, the recognition unit recognizes the action of the operation object as an up and down action relative to the plane where the four or more detection electrodes are located, The recognition unit calculates, for each measurement time point corresponding to the capacitance peak value detected during the action recognition period, a plurality of capacitance change rates R corresponding to the plurality of detection electrodes at each measurement time point according to formula (1), and uses the sum of the plurality of capacitance change rates R as the accumulated capacitance change rate at the measurement time point. R=(C0-C1) / C0……(1), Among them, C0 represents the electrostatic capacitance of a detection electrode at any measurement time point, C1 represents the electrostatic capacitance of the detection electrode at the measurement time point before the any measurement time point, and R represents the capacitance change rate corresponding to the detection electrode at the any measurement time point.

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