TWI679613B - Method for avoiding false alarm by non-fall detection, an apparatus for human fall detection thereof - Google Patents
Method for avoiding false alarm by non-fall detection, an apparatus for human fall detection thereof Download PDFInfo
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Abstract
一種通過非跌倒偵測的防止錯誤警報方法以及跌倒偵測裝置,當穿戴在被照護者身上的裝置產生碰撞訊號時,在碰撞訊號產生後到靜止的一短時間內多次採樣加速度數據,根據計算得出的多筆資料以判斷裝置是否垂直於地面,以此判斷這事件是否真的跌倒,因此可以有效防止錯誤警報。 A false alarm prevention method and a fall detection device through non-fall detection. When a device worn on a person being cared produces a collision signal, the acceleration data is sampled multiple times in a short period of time after the collision signal is generated to stand still. Calculated multiple data to determine whether the device is perpendicular to the ground, to determine whether the event really fell, so it can effectively prevent false alarms.
Description
說明書公開一種跌倒偵測中防止錯誤警報的方法,特別是一種在短時間內統計跌倒偵測器狀態而排除非跌倒事件的防止錯誤警報方法,以及相關裝置。 The specification discloses a method for preventing false alarms in fall detection, particularly a method for preventing false alarms that counts the state of a fall detector in a short time and excludes non-fall events, and related devices.
人的跌倒偵測是照護系統中一個或是最重要的議題,在照護相關領域正在發展跌倒偵測的技術,可應用在老人、體弱、殘障者的照護需求上。 Human fall detection is one of the most important issues in the care system. Fall detection technology is being developed in care-related fields and can be applied to the care needs of the elderly, frail, and disabled.
傳統的跌倒偵測技術一般採用穿戴在被照護者身上的隨身裝置,例如設置有感測器腕帶、項鍊,用以監測被照護者的跌倒動作。 The traditional fall detection technology generally uses a wearable device worn on the person being cared for, such as a sensor wristband and a necklace provided to monitor the person's fall.
舉例來說,在習知技術中,當配戴如腕帶或項鍊等的隨身裝置的被照護者跌倒時,運用其中感測器偵測跌倒動作,感測器例如加速度器與陀螺儀(gyroscope)。一般來說,加速度器用以量測隨身裝置加速度的變化,由於加速度之變化可以反應人體姿態的改變,當加速度變化超過照護系統所設定的門檻時,產生一個跌倒訊號。 For example, in the conventional technology, when a caregiver wearing a portable device such as a wristband or a necklace falls, a sensor in the fall is used to detect the fall motion, such as an accelerometer and a gyroscope. ). Generally speaking, an accelerometer is used to measure the change in the acceleration of a portable device. Since the change in acceleration can reflect the change in the posture of the human body, a fall signal is generated when the change in acceleration exceeds a threshold set by the care system.
當所述加速度器認知到隨身裝置有較大的加速度產生,表示偵測到一碰撞事件。通過以上碰撞與加速度變化等因素,照護系 統可以準確地得知跌倒事件。如此,當照護系統從隨身裝置依序接收到跌倒、碰撞與靜止訊號,將可發出警報。 When the accelerometer recognizes that a larger acceleration is generated by the portable device, it indicates that a collision event is detected. Through the above collision and acceleration changes, the care system The system can accurately know the fall event. In this way, when the care system receives fall, collision and still signals in sequence from the portable device, it will be able to issue an alarm.
傳統的跌倒偵測流程通常是基於加速度值(a(t))隨著時間(t)的改變,從設置於被照護人的隨身裝置中的加速度器產生的數據計算總加速度值(a(t)),可參考圖1所示圖表所敘述的總加速度值(a(t))隨時間(t)變化的趨勢。在跌倒偵測流程中,偵測是否有跌倒事件發生,可以從總加速度值(a(t))隨時間(t)變化的趨勢得出,例如,總加速度值(a(t))接近零時,判斷為自由跌落(free fall)的跌落狀態;當總加速度值(a(t))迅速增加,表示到了碰撞狀態;當總加速度值(a(t))維持一個穩定值,表示進入靜止狀態,這三個狀態成為習知判斷是否有跌倒事件的依據。 The traditional fall detection process is usually based on the change of the acceleration value (a (t)) over time (t), and calculates the total acceleration value (a (t )), Refer to the trend of the total acceleration value (a (t)) as a function of time (t) described in the chart shown in FIG. 1. In the fall detection process, the detection of a fall event can be obtained from the change of the total acceleration value (a (t)) with time (t). For example, the total acceleration value (a (t)) is close to zero. When the total acceleration value (a (t)) increases rapidly, it indicates that it has reached the collision state; when the total acceleration value (a (t)) maintains a stable value, it indicates that it has entered a stationary state. State, these three states become the basis for judging whether there is a fall event.
當隨身裝置中如加速度器的感測器足夠敏感,可以通過加速度值有很大的變化而簡單地感測到跌倒事件,然而在日常生活中的一些動作,也可能使感測器產生類似跌倒的訊息數據,因此,配合跌倒偵測的隨身裝置的照護系統應需要排除誤判的可能性。 When a sensor such as an accelerometer in a portable device is sufficiently sensitive, a fall event can be simply sensed through a large change in acceleration value, however, some actions in daily life may also cause the sensor to have a similar fall Therefore, the care system of the portable device that cooperates with the fall detection should need to rule out the possibility of misjudgment.
說明書公開一種通過非跌倒偵測的防止錯誤警報方法,以及跌倒偵測裝置,其中採用一具有感應器的跌倒偵測裝置事件,應用在被照護者身上,感應器如加速度器,在有碰撞訊號產生後,通過多次加速度變化的偵測排除非跌倒事件,以實現防止錯誤警報,避免因為錯誤訊息使得照護系統誤判,以致於浪費照護系統的資源。 The specification discloses a method for preventing false alarms through non-fall detection, and a fall detection device, in which a fall detection device event with a sensor is applied to a person being cared for, such as an accelerometer, when there is a collision signal After it is generated, non-falling events are eliminated through the detection of multiple acceleration changes to prevent false alarms and avoid misjudgement of the care system due to error messages, which wastes resources of the care system.
此跌倒偵測中防止錯誤警報的方法主要應用於穿戴於一被照護者身上的跌倒偵測裝置中,通過跌倒後到靜止之間的採樣加速度數據判斷是否為真正的跌倒事件,以此排除可能發出錯誤警報的問題。 The method for preventing false alarms in this fall detection is mainly applied to a fall detection device worn on a person being cared for. It is determined whether the fall event is a true fall event by sampling the acceleration data from the fall to the standstill, thereby eliminating the possibility of Issue with false alarm.
當跌倒偵測裝置內的加速度器產生超過門檻的總加速度值 時,判斷為一碰撞事件,並產生碰撞訊號,之後,再於接收碰撞訊號後與達到靜止之前採樣多筆加速度數據。 When the accelerometer in the fall detection device generates a total acceleration value exceeding the threshold At this time, it is judged as a collision event and a collision signal is generated. After that, multiple acceleration data are sampled after receiving the collision signal and before reaching a standstill.
在此流程中,根據採樣的各筆加速度數據之三軸加速度分向量,並計算總加速度,以及垂直參考軸之加速度分向量,根據三軸加速度之分向量、垂直參考軸之加速度分向量、與總加速度計算出垂直變化量,並對照一垂直判斷門檻確認這是跌倒過程中符合非垂直條件的數據,據此可以對採樣的多筆加速度數據都計算垂直變化量,當採樣的多筆加速度數據中符合非垂直條件的數量未達比例門檻,即確認這是非跌倒事件,終止本次跌倒偵測流程。 In this process, the total acceleration and the vertical reference axis acceleration sub-vector are calculated based on the three-axis acceleration sub-vectors of each sampled acceleration data. According to the three-axis acceleration sub-vectors, the vertical reference axis acceleration sub-vectors, and Calculate the amount of vertical change in the total acceleration and confirm it against a vertical judgment threshold. This is data that meets non-vertical conditions during the fall. Based on this, you can calculate the amount of vertical change for multiple samples of acceleration data. If the number of non-vertical conditions in China does not reach the proportional threshold, it is confirmed that this is a non-fall event, and the fall detection process is terminated.
在另一實施例中,在判斷各筆垂直變化量是否符合非垂直條件的步驟中,是根據採樣的各筆加速度數據之三軸加速度分向量,並計算總加速度,與跌倒偵測裝置中加速度器指向地心的一參考向量進行比對,計算出垂直變化量,以此判斷該筆速度數據是否符合非垂直條件。在採樣的多筆加速度數據中,當符合非垂直條件的數量未達一比例門檻,即確認這是非跌倒事件。 In another embodiment, in the step of determining whether the vertical change amount of each pen meets the non-vertical condition, the three-axis acceleration sub-vector of the acceleration data of each sample is sampled, and the total acceleration is calculated, and the acceleration in the fall detection device is calculated. A reference vector pointing to the center of the earth is compared to calculate a vertical change amount, so as to determine whether the speed data meets non-vertical conditions. In the sampled multiple acceleration data, when the number of non-vertical conditions meets a proportional threshold, it is confirmed that this is a non-fall event.
揭露書另關於一種跌倒偵測裝置,裝置中的主要電路有處理器、感測單元,如一加速度器,以及記憶單元,其中記憶單元儲存一指令集,指令集經處理器執行後,即實現上述通過非跌倒偵測的防止錯誤警報方法。 The disclosure also relates to a fall detection device. The main circuit in the device includes a processor, a sensing unit, such as an accelerometer, and a memory unit. The memory unit stores an instruction set. The instruction set is implemented after the processor executes the instruction set. False alarm prevention method with non-fall detection.
為了能更進一步瞭解本發明為達成既定目的所採取之技術、方法及功效,請參閱以下有關本發明之詳細說明、圖式,相信本發明之目的、特徵與特點,當可由此得以深入且具體之瞭解,然而所附圖式僅提供參考與說明用,並非用來對本發明加以限制者。 In order to further understand the technology, methods and effects adopted by the present invention to achieve the intended purpose, please refer to the following detailed descriptions and drawings of the present invention. It is understood, however, the drawings are provided for reference and description only, and are not intended to limit the present invention.
20,20’‧‧‧跌倒偵測裝置 20,20’‧fall detection device
2‧‧‧人 2 people
40‧‧‧參考向量 40‧‧‧reference vector
50‧‧‧跌倒偵測裝置 50‧‧‧fall detection device
501‧‧‧微控制單元 501‧‧‧Micro Control Unit
510‧‧‧重力方向判斷單元 510‧‧‧gravity direction judgment unit
503‧‧‧感測單元 503‧‧‧sensing unit
505‧‧‧記憶單元 505‧‧‧Memory unit
507‧‧‧通訊單元 507‧‧‧communication unit
52‧‧‧照護系統 52‧‧‧care system
步驟S601~S609‧‧‧產生碰撞訊號的流程 Step S601 ~ S609‧‧‧ Generate collision signal flow
步驟S801~S811‧‧‧通過非跌倒偵測的防止錯誤警報流程 Steps S801 ~ S811‧‧‧‧ False alarm prevention process through non-fall detection
圖1顯示的曲線圖描述習知跌倒偵測流程中加速度值a(t)隨著時間的變化曲線;圖2顯示一個人穿戴用以偵測跌倒事件的具有感測器的裝置 實施例示意圖;圖3顯示跌倒偵測裝置中感測器加速度計三個軸向方向的實施例示意圖;圖4顯示跌倒偵測裝置中感測器加速度計三個軸向方向的另一實施例示意圖;圖5顯示具有非跌倒偵測的跌倒偵測裝置主要電路實施例圖;圖6顯示顯示在通過非跌倒偵測的防止錯誤警報方法中產生碰撞訊號的實施例示意圖;圖7顯示在通過非跌倒偵測的防止錯誤警報方法中在碰撞後通過多筆採樣值確認跌倒動作的加速度變化曲線圖;圖8顯示通過非跌倒偵測的防止錯誤警報方法的實施例流程圖。 Figure 1 shows a graph depicting the change in acceleration value a (t) over time in a conventional fall detection process; Figure 2 shows a person wearing a device with a sensor to detect a fall event Schematic diagram of the embodiment; FIG. 3 shows a schematic diagram of an embodiment of a sensor accelerometer in three axial directions in a fall detection device; FIG. 4 shows another embodiment of a triaxial direction of a sensor accelerometer in a fall detection device. Schematic diagram; FIG. 5 shows a main circuit embodiment of a fall detection device with non-fall detection; FIG. 6 shows a schematic diagram of an embodiment that generates a collision signal in a false alarm prevention method by non-fall detection; FIG. 7 shows In the non-fall detection method for preventing false alarms, the acceleration change curve of the fall action is confirmed through multiple sampling values after a collision; FIG. 8 shows a flowchart of an embodiment of the non-fall detection method for preventing false alarms.
說明書公開一種通過非跌倒偵測的防止錯誤警報方法,以及跌倒偵測裝置,其中主要技術特徵是在跌倒偵測裝置產生碰撞訊號後,在碰撞後並達到與靜止之前的一短時間內(如1秒,但並不限制在此時間內)統計跌倒偵測裝置的狀態,通過多次採樣加速度數據判斷裝置是否滿足垂直條件,當滿足非垂直條件之資料數量未達一門檻,如此可以判斷此次事件為不是真的跌倒,以排除非跌倒事件。 The specification discloses a method for preventing false alarms through non-fall detection, and a fall detection device. The main technical feature is that after the collision detection signal is generated by the fall detection device, after a collision and a short period of time before being stationary (such as 1 second, but not limited to this time) Statistics on the state of the fall detection device, and determine whether the device meets the vertical condition by sampling the acceleration data multiple times. When the amount of data that meets the non-vertical condition does not reach a threshold, this can be judged. This event is not a real fall to rule out a non-fall event.
以上所述跌倒偵測裝置如一種穿戴於受照護者的隨身裝置,其中感測器如一加速度器,用以量測裝置隨時間變化的加速度值,所述加速度器可以為三軸加速度器,用以量測三個軸向的加速度分向量,如X軸、Y軸與Z軸的三個加速度分向量分別為ax、ay與az,並據此計算一總加速度值a,一般可知的,三個軸向分向量的向量總和即此總加速度值,總加速度值的大小等於每個加速度分向量的大小平方和的根號,公式如下:
通過非跌倒偵測的防止錯誤警報方法以及相關裝置的目的之一是要避免誤判跌倒的錯誤警報,主要的機制是判斷碰撞後到靜止前的一段時間內裝置是否有符合非垂直的條件。 One of the purposes of the false alarm prevention method and related devices through non-fall detection is to avoid misjudging false alarms for falls. The main mechanism is to determine whether the device meets non-vertical conditions within a period of time from the collision to the time before it is stationary.
圖2示意顯示穿戴於受照護者上的跌倒偵測裝置,其中具有感測器,可用以偵測跌倒事件。 FIG. 2 schematically illustrates a fall detection device worn on a care recipient, which has a sensor for detecting a fall event.
圖中顯示穿戴在一個人2身上的跌倒偵測裝置20,此人2為受照護者,如病患,穿戴跌倒偵測裝置20是用以偵測他的跌倒動作。舉例來說,跌倒偵測裝置20包括感測器,例如加速度器,加速度器量測裝置的加速度值,加速度值表示速度變化率,並可被分為沿著三個軸向的三個分向量。當跌倒偵測裝置處於穩定狀態時,例如靜置在一個桌面上,跌倒偵測裝置內的加速度器量測在地球重力(g~9.81m/s2)影響下的總加速度值,當跌倒偵測裝置為自由落體時,加速度器量測值為零。 The figure shows a fall detection device 20 worn on a person 2 who is a caretaker, such as a patient. The fall detection device 20 is worn to detect his fall. For example, the fall detection device 20 includes a sensor, such as an accelerometer, which measures the acceleration value of the device. The acceleration value represents the rate of change of speed and can be divided into three partial vectors along three axes. . When the fall detection device is in a stable state, such as resting on a desktop, the accelerometer in the fall detection device measures the total acceleration value under the influence of the earth's gravity (g ~ 9.81m / s 2 ). When the measuring device is a free-fall body, the measured value of the accelerometer is zero.
圖3顯示跌倒偵測裝置中感測器三個軸向的方向的實施例示意圖。 FIG. 3 is a schematic diagram illustrating an embodiment of three directions of the sensor in the fall detection device.
跌倒偵測裝置20包括有加速度器,可以即時產生沿著三個彼此垂直的軸向(X,Y,Z)的加速度分向量值,加速度分向量值表示三個軸向的分向量值,如圖顯示的三個加速度分向量值。加速度器可以設計指定一個軸向作為指向地心的參考軸。在一範例中,X軸示意為實質平行於重力方向的軸向,設為垂直參考軸,此垂直參考軸的狀態將可用於判斷跌倒偵測裝置是否處於垂直狀態。在此例中,如果加速度器的X軸方向實質平行重力方向,在X軸量測的加速度分向量相近於總加速度,表示跌倒偵測裝置20處於垂直狀態。 The fall detection device 20 includes an accelerometer, which can generate acceleration sub-vector values along three mutually perpendicular axes (X, Y, Z) in real time. The figure shows the three acceleration sub-vector values. The accelerometer can be designed to specify an axial direction as the reference axis pointing to the center of the earth. In one example, the X axis is an axis substantially parallel to the direction of gravity, and is set as a vertical reference axis. The state of this vertical reference axis can be used to determine whether the fall detection device is in a vertical state. In this example, if the X-axis direction of the accelerometer is substantially parallel to the direction of gravity, the acceleration component vector measured on the X-axis is close to the total acceleration, indicating that the fall detection device 20 is in a vertical state.
然而,在另一實施例中,既使裝置內加速度器的任何軸向都沒有設為指向地心,仍可指定一個平行重力方向的參考向量,作為判斷裝置是否處於垂直狀態的依據,如圖4所示跌倒偵測裝置 中感測器加速度向量的另一實施例示意圖。 However, in another embodiment, even if any axis of the accelerometer in the device is not set to point to the center of the earth, a reference vector parallel to the direction of gravity can be specified as a basis for judging whether the device is in a vertical state, as shown in the figure. Fall detection device shown in 4 A schematic diagram of another embodiment of the middle sensor acceleration vector.
圖4顯示實施例不同於圖3所描述的將跌倒偵測裝置內的加速度的X軸設於朝向地心的軸,圖4所示實施例中的跌倒偵測裝置20’內加速度器的設計並未有任何一軸向是朝向地心,然而,仍可設定一參考向量40,等同跌倒偵測裝置20’在正常狀態(靜止且正常下垂)下加速度器三軸加速度分向量的合向量。因此,這個參考向量40可作為判斷跌倒偵測裝置20’是否正確穿戴於受照護者的參考。 FIG. 4 shows an embodiment in which the X-axis of the acceleration in the fall detection device is set on the axis facing the center of the earth different from that described in FIG. 3. The design of the accelerometer in the fall detection device 20 ′ in the embodiment shown in FIG. 4 is different. None of the axes is oriented toward the center of the earth. However, a reference vector 40 can still be set, which is equivalent to the combined vector of the three-axis acceleration sub-vectors of the accelerometer under the normal state (still and normal droop) of the fall detection device 20 '. Therefore, this reference vector 40 can be used as a reference for judging whether the fall detection device 20 'is correctly worn on the care-giver.
上述實施例描述的跌倒偵測裝置20、20’較佳可為項鍊型式的偵測裝置,可以自然地懸掛在受照護者的身上,其中一軸或是設定的參考向量在裝置運作時是朝向地心。 The fall detection devices 20 and 20 'described in the above embodiments may preferably be necklace-type detection devices, which can be naturally hung on the body of the care recipient. One of the axes or the set reference vector faces the ground when the device is operating. heart.
圖5接著顯示具有非跌倒偵測的跌倒偵測裝置主要電路實施例圖。 FIG. 5 is a diagram illustrating a main circuit of a fall detection device with non-fall detection.
圖中描述的跌倒偵測裝置50,如同穿戴在受照護者身上的隨身裝置,跌倒偵測裝置50使用內部感測器(如加速度器)感測人的移動,此隨身裝置可以項鍊型式的感測裝置呈現,其中處理器接收感測器的資料,並執行跌倒偵測程式。 The fall detection device 50 described in the figure is like a wearable device worn on a person being protected. The fall detection device 50 uses an internal sensor (such as an accelerometer) to sense the movement of a person. The detection device is presented, in which the processor receives data from the sensor and executes a fall detection program.
跌倒偵測裝置50包括有處理器,可以是圖中顯示的微控制單元501,用以處理其中感測單元503產生得資料,感測單元503可以加速度器實現,並耦接於微控制單元501,用以量測跌倒偵測裝置50的加速度數據。在一實施例中,安裝於跌倒偵測裝置50的加速度器如三軸加速度器,用以量測三個軸向的加速度分向量。 The fall detection device 50 includes a processor, which may be the micro-control unit 501 shown in the figure, for processing the data generated by the sensing unit 503. The sensing unit 503 may be implemented by an accelerometer and coupled to the micro-control unit 501. To measure acceleration data of the fall detection device 50. In one embodiment, an accelerometer, such as a triaxial accelerometer, mounted on the fall detection device 50 is used to measure acceleration sub-vectors in three axes.
在此實施例中,微控制單元501包括一軟體實現的重力方向判斷單元510,用來判斷跌倒偵測裝置50是否處於非垂直狀態。舉例來說,當跌倒偵測裝置50內的加速度器的特定軸向(垂直參考軸)或是參考向量並未實質平行於重力方向,表示跌倒偵測裝置50處於非垂直狀態。 In this embodiment, the micro control unit 501 includes a software-implemented gravity direction determination unit 510 for determining whether the fall detection device 50 is in a non-vertical state. For example, when the specific axis (vertical reference axis) or the reference vector of the accelerometer in the fall detection device 50 is not substantially parallel to the direction of gravity, it means that the fall detection device 50 is in a non-vertical state.
跌倒偵測裝置50包括有記憶單元505,耦接於微控制單元 501,作為裝置內的系統記憶體,並特別用來儲存微控制單元501執行的跌倒偵測程式,特別用以儲存一指令集,指令集經處理器(如微控制單元501)執行後,實現揭露書所公開的通過非跌倒偵測的防止錯誤警報方法,其中運行的程序可以通過偵測跌倒偵測裝置50的狀態來避免誤判。 The fall detection device 50 includes a memory unit 505, which is coupled to the micro control unit. 501, as the system memory in the device, and is specifically used to store the fall detection program executed by the micro control unit 501, and is particularly used to store an instruction set, which is implemented after being executed by a processor (such as the micro control unit 501). The disclosed false alarm prevention method through non-fall detection, wherein the running program can avoid misjudgment by detecting the state of the fall detection device 50.
在另一實施例中,跌倒偵測裝置50包括通訊單元507,耦接於微控制單元501,用以與照護系統52通訊,當跌倒偵測裝置50通過跌倒偵測方法偵測到跌倒事件時,將發佈一警報,並通過通訊單元507傳送到照護系統52。 In another embodiment, the fall detection device 50 includes a communication unit 507 coupled to the micro control unit 501 to communicate with the care system 52. When the fall detection device 50 detects a fall event through a fall detection method An alarm will be issued and transmitted to the care system 52 through the communication unit 507.
圖6顯示顯示在通過非跌倒偵測的防止錯誤警報方法中產生碰撞訊號的實施例流程(A)。 FIG. 6 shows a flow chart (A) of an embodiment in which a collision signal is generated in a false alarm prevention method by non-fall detection.
步驟S601表示穿戴於受照護者身上的跌倒偵測裝置的感測器持續產生加速度數據,也就是各軸向的加速度分向量,具有加速值與方向性。在步驟S605中,感測器根據加速度數據,計算出判斷是否有碰撞產生的加速度值。 Step S601 indicates that the sensor of the fall detection device worn on the person being protected continuously generates acceleration data, that is, acceleration sub-vectors of each axis, which have acceleration values and directivity. In step S605, the sensor calculates an acceleration value for determining whether there is a collision based on the acceleration data.
在步驟S607中,感測器判斷是否所計算得到的總加速度值大於第一門檻,這是系統設定用以判斷是否有碰撞產生的門檻值,也就是,在感測器中,將持續地將感測到的各軸向加速度分向量並計算總加速度值,再通過比對第一門檻來判斷是否有碰撞事件,若並不大於第一門檻,表示是一般情況,流程回到步驟S601;若加速度值大於此第一門檻,將產生碰撞訊號,如步驟S609。 In step S607, the sensor determines whether the calculated total acceleration value is greater than the first threshold. This is a threshold value set by the system to determine whether a collision occurs. That is, in the sensor, the sensor will continuously Sense the axial acceleration sub-vectors and calculate the total acceleration value, and then compare the first threshold to determine whether there is a collision event. If it is not greater than the first threshold, it indicates that it is normal, and the process returns to step S601; If the acceleration value is greater than this first threshold, a collision signal will be generated, as in step S609.
相較於傳統根據如圖1所示跌倒過程中跌落、碰撞與靜止三個階段的加速值變化來判斷跌倒的方式,揭露書所提出的通過非跌倒偵測的防止錯誤警報方法更進一步根據被照護者跌倒過程中跌倒偵測裝置是否有垂直角度的變化來排除跌倒誤判。 Compared with the traditional method of judging a fall based on changes in the acceleration values of the three stages of fall, collision, and stillness as shown in Figure 1, the method of preventing false alarms through non-fall detection proposed in the disclosure goes further. Whether the fall detection device has a vertical angle change during the fall of the caregiver to eliminate the fall misjudgment.
舉例來說,從實施跌倒偵測可知,在被照護者真正發生跌倒時,從撞擊地面的過程中,所穿戴的跌倒偵測裝置中設定的一個方向(垂直參考軸或參考向量)將會從垂直於地面改為非垂直於 地面。 For example, from the implementation of fall detection, it can be known that when the caretaker actually falls, from the process of hitting the ground, a direction (vertical reference axis or reference vector) set in the fall detection device worn will be changed from Perpendicular to ground instead of non-perpendicular ground.
反之,當被照護者在一般正常的活動中,例如坐下或是彎腰,使用者偶爾發生碰撞(加速度器感應到較大加速度值變化),但發生碰撞後的一段時間內,跌倒偵測裝置中的垂直參考軸向或參考向量與地面的垂直角度不會發生太大的變化,這樣的情況並不是跌倒。 Conversely, when the care-giver is in normal activities, such as sitting down or bending down, the user occasionally collides (the accelerometer detects a large acceleration value change), but falls within a period of time after the collision, and the fall detection The vertical reference axis or vertical angle of the reference vector and the ground in the device will not change much, and such a situation is not a fall.
值得一提的是,當照護者跌倒後靜止躺在地面時,所穿戴的跌倒偵測裝置仍有可能懸吊在身體旁邊而使得其中設定的垂直參考軸或參考向量垂直於地面,因此在偵測裝置處於靜止狀態後若穿戴裝置垂直於地面,不應判斷為非跌倒。 It is worth mentioning that when a caregiver lays still on the ground after a fall, the fall detection device worn may still hang next to the body so that the vertical reference axis or reference vector set therein is perpendicular to the ground, so If the wearable device is perpendicular to the ground after the test device is at a standstill, it should not be judged as non-falling.
因此,以通過非跌倒偵測的防止錯誤警報方法判斷是否跌倒時,將在被照護者碰撞發生(如倒在地面)到靜止(躺在地面不動)之間的一段時間內(例如,約一秒鐘),判斷跌倒偵測裝置是否產生垂直角度的變化,藉此能排除被照護者在一般活動產生的訊號造成的誤判。 Therefore, when judging whether to fall through the false alarm prevention method through non-fall detection, the caretaker will be in a period of time (for example, about one Seconds) to determine whether the fall detection device produces a vertical angle change, thereby eliminating misjudgments caused by signals generated by the caregiver during normal activities.
在描述圖8的流程之前,參考圖7所示在通過非跌倒偵測的防止錯誤警報方法中在碰撞後的一時間內(如1秒)通過多筆採樣值確認跌倒動作的加速度變化曲線圖。 Before describing the flow of FIG. 8, referring to FIG. 7, in a method for preventing false alarms through non-fall detection, the acceleration change curve of the fall action is confirmed through multiple sampling values within a time (such as 1 second) after the collision. .
圖7顯示一個跌倒事件的總加速度(a(t))隨著時間(t)的變化曲線,第一段時間顯示跌落的過程的總加速度值變化,接著,當被照護者碰撞地面或是任何物品,將會產生一個總加速度值變化量更大的值,也就是第二段時間顯示的碰撞,接著,如第三段時間,跌倒偵測裝置將隨著被照護者靜止不動而沒有過大的總加速度值變化。 Figure 7 shows the change of the total acceleration (a (t)) of a fall event over time (t). The first period shows the change in the total acceleration value of the fall process. Then, when the caregiver hits the ground or any The article will produce a larger change in the total acceleration value, that is, the collision displayed in the second period. Then, as in the third period, the fall detection device will not be too large as the caretaker is stationary. The total acceleration value changes.
在第二段時間中,即從發生碰撞到靜止的過程中,垂直參考軸的分向量(ax(t))與總加速度值具有較大差異,即代表跌倒偵測裝置已經產生垂直角度的變化。反之,若為一般活動產生的訊號,垂直參考軸的分向量(ax(t))接近於總加速度值。 In the second period of time, that is, from the collision to the standstill, the sub-vector (ax (t)) of the vertical reference axis is significantly different from the total acceleration value, which means that the fall detection device has produced a change in the vertical angle. . Conversely, if it is a signal generated by general activities, the sub-vector (ax (t)) of the vertical reference axis is close to the total acceleration value.
在第三段時間中,即被照護者靜止不動的狀態下,由於跌倒偵測裝置懸吊在身體旁邊而使其中設定的垂直參考軸垂直於地面,因此垂直參考軸的分向量(ax(t))接近於總加速度值。 In the third period of time, that is, when the person being cared for still, the fall detection device is suspended beside the body and the vertical reference axis set therein is perpendicular to the ground, so the sub-vector of the vertical reference axis (ax (t )) Close to the total acceleration value.
在通過非跌倒偵測的防止錯誤警報方法的應用中,由於加速度器在碰撞到靜止狀態之間會有非垂直於地面的現象,處理器中運行的程序將在碰撞到靜止之間採用多筆加速度數據,以統計方式確認其中垂直參考軸或是設定指向地心的參考向量確實達到非垂直的條件,避免僅以一筆或是過於少量的數據作為排除誤判的依據。 In the application of the method of preventing false alarms through non-fall detection, because the accelerator will be non-vertical to the ground between the collision and the stationary state, the program running in the processor will use multiple strokes between the collision and the stationary state. Acceleration data, statistically confirm that the vertical reference axis or the reference vector pointing to the center of the earth does reach the non-vertical condition, and avoid using only one or too small amount of data as a basis for excluding misjudgment.
在圖8的流程(B)中,在步驟S801接收到碰撞訊號後,步驟S803從碰撞到靜止的一段時間之內採樣多筆加速度數據。由於被照護者在一般活動時,跌倒偵測裝置中的感測器仍會被干擾而產生造成誤判的值,因此需要多次取樣,到靜止之前採樣多筆加速度數據,並如步驟S805,分別根據採樣的各筆加速度數據計算垂直變化量,計算垂直變化量adiff的公式如下:
在另一實施例中,若沒有任何一個加速度軸向是指向地心的,則系統指定一指向地心的參考向量(axref,ayref,azref),此參考向量為當跌倒裝置靜止且垂直於地面時,三軸加速度計所量得之三軸分向量。 In another embodiment, if none of the acceleration axes is directed to the center of the earth, the system specifies a reference vector (a xref , a yref , a zref ) that points to the center of the earth. This reference vector is when the fall device is stationary and When perpendicular to the ground, the triaxial sub-vector measured by the triaxial accelerometer.
經過運算得到垂直變化量adiff如下:
值得一提的是,系統指定一指向地心的垂直參考軸之實施例 屬於參考向量實施例之一特例,在此特例中,參考向量(axref,ayref,azref)的值剛好等於(1,0,0),因此參考向量實施例之垂直變化量之公式即可簡化為具系統指定垂直參考軸之垂直變化量公式。 It is worth mentioning that the embodiment in which the system specifies a vertical reference axis pointing to the center of the earth is a special case of the reference vector embodiment. In this special case, the value of the reference vector (a xref , a yref , a zref ) is just equal to ( 1,0,0), so the formula of the vertical variation of the reference vector embodiment can be simplified to the formula of the vertical variation with the system-specified vertical reference axis.
接著,判斷這個垂直變化量是否符合非垂直條件,如步驟S807。在此步驟中,可以比對系統設定作為判斷垂直與否的一垂直判斷門檻athv,若該垂直變化量大於該垂直判斷門檻,則視為裝置非垂直於地面:a diff >a thv ,且因為為了要排除被照護者一般活動狀態下仍會讓感測器產生會造成誤判的錯誤訊號,因此需要多次採樣,並且滿足非垂直條件的數量在全部採樣值中達一定的比例門檻,才能視為跌倒事件。如此,在此次跌倒事件中從取樣的多筆採樣值計算出多筆垂直變化量,當大於垂直判斷門檻的次數並未達一定的比例門檻,將視為不符合跌倒時的非垂直條件(否),即如步驟S811,即終止本次跌倒偵測流程,並要回到最初判斷是否有碰撞訊號的流程(A)。反之,當大於垂直判斷門檻的次數達到設定的比例門檻,表示有足夠的採樣值被判斷為非垂直,也就符合非垂直條件(是),系統即繼續進行其它跌倒條件的判斷(步驟S809)。 Next, it is determined whether the vertical change amount meets a non-vertical condition, as in step S807. In this step, the system can be set as a vertical judgment threshold a thv for judging whether it is vertical or not. If the vertical variation is larger than the vertical judgment threshold, it is regarded that the device is not perpendicular to the ground: a diff > a thv , and Because in order to eliminate the caretaker's normal activity, the sensor will still generate false signals that will cause misjudgment. Therefore, multiple sampling is required, and the number of non-vertical conditions that meet a certain proportion threshold in all sampling values. Think of a fall. In this way, in this fall event, multiple vertical changes are calculated from the sampled multiple sampling values. When the number of times that exceeds the vertical judgment threshold does not reach a certain percentage threshold, it will be considered as not meeting the non-vertical condition at the time of the fall ( No), that is, if step S811 is executed, the current fall detection process is terminated, and the process (A) for judging whether there is a collision signal is initially returned. Conversely, when the number of times that exceeds the vertical judgment threshold reaches the set proportional threshold, it means that enough sampling values are judged to be non-vertical, which also meets the non-vertical condition (Yes), and the system continues to judge other fall conditions (step S809) .
綜上所述,以上實施例描述一種跌倒偵測中防止錯誤警報的方法,以及相關裝置,主要是一種在短時間內快速統計跌倒偵測器狀態而排除非跌倒事件的防止錯誤警報方法,其中主要的方式是在碰撞訊號產生後一段時間內多次採樣加速度數據,通過非垂直條件的判斷,確認該事件是否不是真的跌倒事件,可以有效防止錯誤警報。 In summary, the above embodiments describe a method for preventing false alarms in fall detection and related devices, which are mainly a method for preventing false alarms that quickly counts the state of the fall detector to exclude non-fall events in a short period of time. The main method is to sample the acceleration data multiple times within a period of time after the collision signal is generated, and to determine whether the event is not a real fall event through judgment of non-vertical conditions, which can effectively prevent false alarms.
以上所述僅為本發明之較佳可行實施例,凡依本發明申請專利範圍所做之均等變化與修飾,皆應屬本發明之涵蓋範圍。 The above descriptions are only the preferred and feasible embodiments of the present invention, and any equivalent changes and modifications made in accordance with the scope of patent application of the present invention shall fall within the scope of the present invention.
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