技术领域technical field
本发明关于一种心跳检测模组，特别是关于一种具有去噪功能的心跳检测模组及其检测、去噪方法。The present invention relates to a heartbeat detection module, in particular to a heartbeat detection module with denoising function and a detection and denoising method thereof.
背景技术Background technique
已知血氧饱和仪(pulse oximeter)利用非侵入式的方式来检测使用者的血氧浓度和脉搏数，其可产生红光光束(波长约660纳米)和红外光光束(波长约910纳米)穿透待测部位，并利用带氧血红素(oxyhemoglobin)和去氧血红素(deoxyheamoglobin)对特定光谱具有不同吸收率的特性以检测穿透光的光强度变化，例如参照美国专利第7,072,701号，标题为血氧浓度的监测方式(Method for spectrophotometric blood oxygenationmonitoring)。检测出两种波长的穿透光的光强度变化后，例如光体积变化(Photoplethysmography)信号或称作PPG信号(PPG signal)，再以下列公式计算血氧浓度，血氧浓度＝100％×[HbO2]/([HbO2]+[Hb])；其中，[HbO2]表示带氧血红素浓度；[Hb]表示去氧血红素浓度。It is known that a pulse oximeter uses a non-invasive method to detect the blood oxygen concentration and pulse rate of the user, and it can generate a red light beam (wavelength of about 660 nm) and an infrared light beam (wavelength of about 910 nm). Penetrate the site to be tested, and use oxyhemoglobin and deoxyhemoglobin to have different absorbance characteristics for specific spectra to detect the change of light intensity of the transmitted light, for example, refer to U.S. Patent No. 7,072,701, The title is Method for spectrophotometric blood oxygenation monitoring. After detecting the change of the light intensity of the transmitted light of the two wavelengths, such as the photoplethysmography signal or the PPG signal (PPG signal), the blood oxygen concentration is calculated by the following formula, blood oxygen concentration = 100% × [ HbO2]/([HbO2]+[Hb]); wherein, [HbO2] represents the concentration of oxygenated heme; [Hb] represents the concentration of deoxygenated heme.
一般血氧饱和仪所检测到的两种波长的穿透光的光强度会随着心跳而呈现强弱变化，这是由于血管会随着心跳而不断地扩张和收缩而使得光束所通过的血液量改变，进而改变光能量被吸收的比例。藉此，根据不断变化的光强度信息可计算使用者的心跳。Generally, the light intensity of the two wavelengths of transmitted light detected by the oximeter will change with the heartbeat. This is because the blood vessels will continue to expand and contract with the heartbeat, so that the blood through which the beam passes The amount of light changes, thereby changing the proportion of light energy absorbed. Thereby, the user's heartbeat can be calculated according to the constantly changing light intensity information.
然而，当血氧饱和仪与所检测的待测部位发生相对移动时，则会检测到混乱波形而难以检测出正确的光体积变化信号，因而在非静止状态的检测条件下(例如应用在可携式电子装置或穿戴式电子装置时)，可能无法得到正确的心跳。However, when the oximeter and the detected part move relative to each other, the chaotic waveform will be detected and it is difficult to detect the correct light volume change signal. Portable electronic device or wearable electronic device), it may not be able to get the correct heartbeat.
发明内容SUMMARY OF THE INVENTION
有鉴于此，本发明提出一种具有去噪功能的心跳检测模组及其检测、去噪方法。In view of this, the present invention provides a heartbeat detection module with denoising function and a detection and denoising method thereof.
本发明提供一种心跳检测模组。所述心跳检测模组包含光体积测量装置、运动感测装置和处理单元。所述光体积测量装置用以在检测期间检测皮肤表面以输出光体积变化信号。所述运动感测装置用以相对所述检测期间输出加速度信号。所述处理单元用以分别转换所述光体积变化信号和所述加速度信号为第一频域信息和第二频域信息、根据所述第二频域信息的最大频谱峰值决定去噪参数以对所述第一频域信息去噪以及根据去噪后第一频域信息的最大频谱峰值计算心跳。The present invention provides a heartbeat detection module. The heartbeat detection module includes a photovolume measuring device, a motion sensing device and a processing unit. The photovolume measurement device is used to detect the skin surface during detection to output a photovolume change signal. The motion sensing device is used for outputting an acceleration signal relative to the detection period. The processing unit is configured to convert the photovolume change signal and the acceleration signal into first frequency domain information and second frequency domain information respectively, and determine a denoising parameter according to the maximum spectral peak value of the second frequency domain information to The first frequency domain information is denoised and the heartbeat is calculated according to the maximum spectrum peak of the denoised first frequency domain information.
本发明还提供一种适用于心跳检测模组的心跳检测方法，所述心跳检测模组包含光体积测量装置、运动感测装置和处理单元。所述心跳检测方法包含下列步骤：以所述光体积测量装置在检测期间检测皮肤表面以输出光体积变化信号；以所述运动感测装置相对所述检测期间输出加速度信号；以所述处理单元接收所述光体积变化信号和所述加速度信号；分别转换所述光体积变化信号和所述加速度信号为第一频域信息和第二频域信息；根据所述第二频域信息的最大频谱峰值决定去噪参数以对所述第一频域信息去噪；以及根据去噪后第一频域信息的最大频谱峰值计算心跳。The present invention also provides a heartbeat detection method suitable for a heartbeat detection module, wherein the heartbeat detection module includes a photovolume measuring device, a motion sensing device and a processing unit. The heartbeat detection method includes the following steps: using the photovolume measuring device to detect the skin surface during detection to output a photovolume change signal; using the motion sensing device to output an acceleration signal relative to the detection period; using the processing unit receiving the photovolume change signal and the acceleration signal; respectively converting the photovolume change signal and the acceleration signal into first frequency domain information and second frequency domain information; according to the maximum frequency spectrum of the second frequency domain information The peak determines a denoising parameter to denoise the first frequency domain information; and calculates a heartbeat according to the maximum spectral peak of the denoised first frequency domain information.
本发明还提供一种心跳检测模组的去噪方法。所述去噪方法包含下列步骤：在检测期间接收光体积变化信号和加速度信号；转换所述光体积变化信号为频域光体积变化信号并产生具有第一组频率索引值和相关的第一组频谱值的第一频域信息；转换所述加速度信号为频域加速度信号并产生具有第二组频率索引值和相关的第二组频谱值的第二频域信息；识别所述第一频域信息中前三大频谱峰值所对应的三个频率索引值和所述第二频域信息中最大频谱峰值所对应的参考索引值；以及根据所述三个频率索引值和所述参考索引值对所述第一组频谱值进行去噪。The invention also provides a denoising method for the heartbeat detection module. The denoising method comprises the steps of: receiving a photovolumetric signal and an acceleration signal during detection; converting the photovolumetric signal to a frequency-domain photovolumetric signal and generating a first set having a first set of frequency index values and correlations first frequency domain information of spectral values; converting the acceleration signal into a frequency domain acceleration signal and generating second frequency domain information having a second set of frequency index values and an associated second set of spectral values; identifying the first frequency domain The three frequency index values corresponding to the top three spectral peaks in the information and the reference index value corresponding to the largest spectral peak in the second frequency domain information; and according to the three frequency index values and the reference index value pair The first set of spectral values is denoised.
为了让本发明的上述和其他目的、特征和优点能更明显，下文将配合所附图示，详细说明如下。此外，在本发明的说明中，相同的构件以相同的符号表示，在此先述明。In order to make the above and other objects, features and advantages of the present invention more apparent, the following detailed description will be given in conjunction with the accompanying drawings. In addition, in the description of this invention, the same member is shown by the same code|symbol, and it demonstrates it here.
附图说明Description of drawings
图1为本发明实施例的心跳检测模组的方块图；1 is a block diagram of a heartbeat detection module according to an embodiment of the present invention;
图2A为本发明实施例的滤波前光体积变化信号的示意图；2A is a schematic diagram of an optical volume change signal before filtering according to an embodiment of the present invention;
图2B为本发明实施例的滤波后光体积变化信号的示意图；2B is a schematic diagram of an optical volume change signal after filtering according to an embodiment of the present invention;
图3为本发明实施例的心跳检测方法的流程图；3 is a flowchart of a heartbeat detection method according to an embodiment of the present invention;
图4A为本发明实施例的频域光体积变化信号的频谱图；4A is a spectrum diagram of a frequency-domain photovolume change signal according to an embodiment of the present invention;
图4B为对应图4A的频谱图的第一频域信息的示意图；4B is a schematic diagram of the first frequency domain information corresponding to the spectrogram of FIG. 4A;
图5A为本发明实施例的频域加速度信号的频谱图；5A is a spectrum diagram of a frequency-domain acceleration signal according to an embodiment of the present invention;
图5B为对应图5A的频谱图的第二频域信息的示意图；5B is a schematic diagram of second frequency domain information corresponding to the spectrogram of FIG. 5A;
图6为本发明实施例的第一频域信息和第二频域信息的示意图；6 is a schematic diagram of first frequency domain information and second frequency domain information according to an embodiment of the present invention;
图7为本发明实施例的去噪方法的流程图；7 is a flowchart of a denoising method according to an embodiment of the present invention;
图8为本发明实施例的频率索引值、参考索引值和去噪范围的示意图。FIG. 8 is a schematic diagram of a frequency index value, a reference index value, and a denoising range according to an embodiment of the present invention.
附图标记说明Description of reference numerals
1 心跳检测模组1 Heartbeat detection module
10 光体积测量装置10 Photovolume measuring device
12 运动感测装置12 Motion Sensing Device
14 处理单元14 processing units
140 转换模组140 Conversion Modules
142 峰值萃取模组142 Peak Extraction Modules
144 计算模组144 Computing Modules
146 心跳追踪模组146 Heartbeat Tracking Module
16 带通滤波器16 Bandpass filter
18 表示单元18 means unit
I1 第一频域信息I1 first frequency domain information
I2 第二频域信息I2 Second frequency domain information
N1、N2、N3 频率索引值N1 , N2 , N3 frequency index values
NHR 心跳索引值NHR heartbeat index value
PMAX 最大频谱峰值PMAX maximum spectral peak
PMAX′ 去噪后最大频谱峰值PMAX ′ maximum spectral peak after denoising
R 参考索引值R reference index value
R1/2 二分之一倍参考索引值R1/2 half the reference index value
R2 两倍参考索引值R2 double the reference index value
S10-S25 步骤S10 -S25 steps
Sa 加速度信号Sa acceleration signal
Sp 光体积变化信号Sp photovolume change signal
具体实施方式Detailed ways
本发明提供一种具有去噪功能的心跳检测模组，可结合于例如，但不限于，智慧型手表、手环、眼镜、穿戴式装置或行动装置。某些实施例中，所述穿戴式装置或行动装置可包含或不包含显示功能。某些实施例中，所述心跳检测模组可为独立的检测装置并可利用适当方式结合于所述装置，在需要使用时才进行设置，以增加实用性。The present invention provides a heartbeat detection module with denoising function, which can be combined with, for example, but not limited to, smart watches, wristbands, glasses, wearable devices or mobile devices. In some embodiments, the wearable device or mobile device may or may not include a display function. In some embodiments, the heartbeat detection module can be an independent detection device and can be combined with the device in an appropriate manner, and can be set only when it is needed to increase practicality.
请参照图1所示，其为本发明实施例的心跳检测模组1的方块图，包含光体积测量装置10、运动感测装置12和处理单元14，其中所述处理单元14包含转换模组140、峰值萃取模组142和计算模组144。某些实施例中，两个带通滤波器16分别设置在所述光体积测量装置10与所述处理单元14之间以及所述运动感测装置12与所述处理单元14之间。某些实施例中，所述处理单元14还包含心跳追踪模组146用以记录所述计算模组144所计算的心跳。可以了解的是，电源模组(未绘示)电性连接所述心跳检测模组1并用以提供所述心跳检测模组1操作时所需的电力。Please refer to FIG. 1 , which is a block diagram of a heartbeat detection module 1 according to an embodiment of the present invention, including a photovolume measurement device 10 , a motion sensing device 12 and a processing unit 14 , wherein the processing unit 14 includes a conversion module 140 , a peak extraction module 142 and a calculation module 144 . In some embodiments, two bandpass filters 16 are disposed between the photovolume measurement device 10 and the processing unit 14 and between the motion sensing device 12 and the processing unit 14, respectively. In some embodiments, the processing unit 14 further includes a heartbeat tracking module 146 for recording the heartbeat calculated by the computing module 144 . It can be understood that a power module (not shown) is electrically connected to the heartbeat detection module 1 and used to provide power required for the operation of the heartbeat detection module 1 .
所述光体积测量装置10用以在检测期间检测皮肤表面以输出光体积变化信号Sp。一般而言，所述光体积测量装置10具有发光模组和感测区。所述光体积测量装置10可为反射式或穿透式光体积测量装置，并无特定限制。所述光体积测量装置10根据检测光信号产生光体积变化信号的方式已为已知，故在此不再赘述。所述光体积测量装置10所检测皮肤表面的位置并无特定限制，其根据所适用的电子装置。The photovolume measurement device 10 is used to detect the skin surface during detection to output a photovolume change signal Sp. Generally speaking, the photometric device 10 has a light-emitting module and a sensing area. The photometric device 10 can be a reflective or transmissive photometric device, and there is no specific limitation. The manner in which the light volume measuring device 10 generates the light volume change signal according to the detected light signal is already known, so it will not be repeated here. The position of the skin surface detected by the photometric device 10 is not particularly limited, depending on the applicable electronic device.
所述运动感测装置12例如可为陀螺仪(gyroscope)、加速度计(accelerometer)、重力感测器(G sensor)或其他用以感测人体运动的装置。本实施例中，所述运动感测装置12以加速度计为例进行说明，其用以相对所述光体积测量装置10的所述检测期间输出加速度信号Sa，以使所述加速度信号Sa与所述光体积变化信号Sp具有对应关系。在一实施例中，所述运动感测装置12可利用微机电系统(micro-electro-mechanical systems,MEMS)的技术制作而成。The motion sensing device 12 may be, for example, a gyroscope, an accelerometer, a gravity sensor (G sensor) or other devices for sensing human motion. In this embodiment, the motion sensing device 12 is described by taking an accelerometer as an example, which is used for outputting an acceleration signal Sa during the detection period relative to the photovolume measuring device 10, so that the acceleration signal Sa and all The light volume change signal Sp has a corresponding relationship. In one embodiment, the motion sensing device 12 can be fabricated by using the technology of micro-electro-mechanical systems (MEMS).
本实施例中，所述心跳检测模组1具有两个带通滤波器16分别设置在所述光体积测量装置10与所述处理单元14之间和所述运动感测装置12与所述处理单元14之间，并用以对所述光体积变化信号Sp和所述加速度信号Sa进行滤波。例如，图2A和图2B分别显示所述光体积变化信号Sp通过所述带通滤波器16前后的示意图，其中x轴表示时间且y轴表示振幅。一般而言，人类心跳介于30次/分至240次/分之间，根据心跳60次/分对应1Hz的情况下，人类心跳的信号频率范围为0.5Hz至4Hz。因此，所述带通滤波器16的通带(passband)例如可从0.5Hz至4Hz或从0.45Hz至4.5Hz以增加所述光体积变化信号Sp和所述加速度信号Sa的信号品质(也即滤除与人类心跳信号不相关的频率)，但不限于此。为简化说明，本发明说明中，所述带通滤波器16滤波后的所述光体积变化信号和所述加速度信号仍分别以符号Sp和Sa表示。In this embodiment, the heartbeat detection module 1 has two bandpass filters 16 respectively disposed between the photovolume measuring device 10 and the processing unit 14 and between the motion sensing device 12 and the processing unit 14 , respectively. between the units 14 and used to filter the photovolume change signal Sp and the acceleration signal Sa. For example, FIGS. 2A and 2B respectively show schematic diagrams of the photovolume change signal Sp before and after passing through the bandpass filter 16 , wherein the x-axis represents time and the y-axis represents amplitude. Generally speaking, the human heartbeat ranges from 30 beats/min to 240 beats/min. According to the case where 60 beats/min corresponds to 1 Hz, the signal frequency of the human heartbeat ranges from 0.5 Hz to 4 Hz. Therefore, the passband of the band pass filter 16 may be, for example, from 0.5 Hz to 4 Hz or from 0.45 Hz to 4.5 Hz to increase the signal quality of the photovolume change signal Sp and the acceleration signal Sa (ie, filter out frequencies unrelated to human heartbeat signals), but not limited to this. To simplify the description, in the description of the present invention, the light volume change signal and the acceleration signal filtered by the bandpass filter 16 are still represented by symbols Sp and Sa, respectively.
必须说明的是，虽然图1显示所述带通滤波器16未包含在所述处理单元14之中，但本发明并不限于此。某些实施例中，所述带通滤波器16可分别设置在所述光体积测量装置10和所述运动感测装置12之中。某些实施例中，所述带通滤波器16可设置在所述处理单元14之中。It must be noted that although FIG. 1 shows that the bandpass filter 16 is not included in the processing unit 14 , the present invention is not limited thereto. In some embodiments, the bandpass filter 16 may be disposed in the photovolume measurement device 10 and the motion sensing device 12, respectively. In some embodiments, the bandpass filter 16 may be provided in the processing unit 14 .
所述处理单元14例如为数字信号处理器(digital signal processor,DSP)或其他可用以进行信号处理的处理装置，并可利用软体、硬体或韧体的方式实现其运算功能。所述处理单元14可用以根据所述加速度信号Sa消除所述光体积变化信号Sp中，由于所述光体积测量装置10的感测区与皮肤表面相对运动所产生的噪声。例如，某些实施例中，所述处理单元14分别转换所述光体积变化信号Sp和所述加速度信号Sa为第一频域信息I1和第二频域信息I2、根据所述第二频域信息I2的最大频谱峰值决定去噪参数以对所述第一频域信息I1去噪以及根据去噪后第一频域信息的最大频谱峰值计算心跳。The processing unit 14 is, for example, a digital signal processor (DSP) or other processing devices that can be used for signal processing, and can use software, hardware or firmware to implement its computing functions. The processing unit 14 can be configured to eliminate the noise generated by the relative movement of the sensing area of the photovolume measurement device 10 and the skin surface in the photovolume change signal Sp according to the acceleration signal Sa. For example, in some embodiments, the processing unit 14 converts the photovolume change signal Sp and the acceleration signal Sa into the first frequency domain information I1 and the second frequency domain information I2 , according to the second frequency domain information I 2 , respectively. The maximum spectral peak value of the frequency domain informationI2 determines a denoising parameter to denoise the first frequency domain informationI1 and calculate the heartbeat according to the maximum spectral peak value of the denoised first frequency domain information.
所述处理单元14的所述转换模组140用以转换所述光体积变化信号Sp为频域光体积变化信号并产生第一组频率索引值和相关的第一组频谱值以作为所述第一频域信息I1，并转换所述加速度信号Sa为频域加速度信号并产生第二组频率索引值和相关的第二组频谱值以作为所述第二频域信息I2。The conversion module 140 of the processing unit 14 is used to convert the photovolume change signal Sp into a frequency domain photovolume change signal and generate a first set of frequency index values and a first set of related spectral values as the first set of frequency index values. obtain frequency domain information I1 , convert the acceleration signal Sa into a frequency domain acceleration signal, and generate a second set of frequency index values and a second set of related spectral values as the second frequency domain information I2 .
所述处理单元14的所述峰值萃取模组142用以判断所述第一频域信息I1和所述第二频域信息I2中多个频谱峰值，并输出对应所述频谱峰值的频率索引值至所述计算模组144。The peak extraction module 142 of the processing unit 14 is used to determine a plurality of spectral peaks in the first frequency domain informationI1 and the second frequency domain informationI2 , and output frequencies corresponding to the spectral peaks Index value to the calculation module 144 .
所述处理单元14的所述计算模组144用以根据对应所述频谱峰值的频率索引值排除所述第一频域信息I1中的噪声以计算心跳(详述于后)。The calculation module 144 of the processing unit 14 is configured to exclude noise in the first frequency domain informationI1 according to the frequency index value corresponding to the spectral peak to calculate the heartbeat (details will be described later).
所述心跳追踪模组146用以对应多个所述检测期间记录所述心跳的变化趋势以至于当所述计算模组144无法根据去噪后第一频域信息直接计算心跳时，还可根据所述变化趋势估测所述心跳(详述于后)。The heartbeat tracking module 146 is used to record the change trend of the heartbeat corresponding to a plurality of the detection periods, so that when the calculation module 144 cannot directly calculate the heartbeat according to the first frequency domain information after denoising, it can also The trend estimates the heartbeat (detailed below).
可以了解的是，本实施例的所述转换模组140、所述峰值萃取模组142、所述计算模组144和所述心跳追踪模组146表示所述处理单元14内部的功能方块(function block)或程式指令(program instruction)。可以了解的是，其他实施例中，所述转换模组140、所述峰值萃取模组142、所述计算模组144和所述心跳追踪模组146可以不同的处理单元实现。必须说明的是，虽然图1中显示两转换模组140和两峰值萃取模组142，但本发明不限于此，所述处理单元14可仅包含转换模组140和峰值萃取模组142。It can be understood that the conversion module 140 , the peak extraction module 142 , the calculation module 144 and the heartbeat tracking module 146 in this embodiment represent functional blocks inside the processing unit 14 . block) or program instruction. It can be understood that, in other embodiments, the conversion module 140 , the peak extraction module 142 , the calculation module 144 and the heartbeat tracking module 146 may be implemented by different processing units. It must be noted that, although two conversion modules 140 and two peak extraction modules 142 are shown in FIG. 1 , the present invention is not limited thereto, and the processing unit 14 may only include the conversion module 140 and the peak extraction module 142 .
某些实施例中，所述心跳检测模组1可包含表示单元18用以通过声音或影像的方式表示所述心跳，例如所述表示单元18包含扬声器或显示器等。此时所述电源模组还提供所述表示单元18所需的电力。In some embodiments, the heartbeat detection module 1 may include a display unit 18 for representing the heartbeat through audio or video, for example, the display unit 18 includes a speaker or a display. At this time, the power module also provides the power required by the presentation unit 18 .
某些实施例中，所述表示单元18不包含在所述心跳检测模组1之中，例如当所述心跳检测模组1整合在智慧型手环时，所述表示单元18可为智慧型手机的屏幕。此时，所述心跳检测模组1通过无线的方式(例如蓝牙、Wi-Fi、ZigBee或其他无线通讯协定)从所述智慧型手环传送包含心跳信息的信号至所述智慧型手机以显示即时心跳及其变化趋势。In some embodiments, the display unit 18 is not included in the heartbeat detection module 1. For example, when the heartbeat detection module 1 is integrated into a smart bracelet, the display unit 18 can be a smart wristband. phone screen. At this time, the heartbeat detection module 1 transmits a signal including heartbeat information from the smart bracelet to the smart phone by wireless means (such as Bluetooth, Wi-Fi, ZigBee or other wireless communication protocols) to display Instant heartbeat and its changing trend.
某些实施例中，所述表示单元18设置在连结云端系统(cloud system)的电脑系统，此时所述心跳检测模组1通过无线的方式传送包含心跳信息的信号至所述云端系统以供所述云端系统记录所述心跳。在医疗应用上，医护人员可通过所述电脑系统监控所述使用者的心跳。In some embodiments, the display unit 18 is set in a computer system connected to a cloud system, and at this time the heartbeat detection module 1 transmits a signal including heartbeat information to the cloud system by wireless means. The cloud system records the heartbeat. In medical applications, medical staff can monitor the user's heartbeat through the computer system.
可以了解的是，所述心跳检测模组1所检测的心跳可作为各种不同应用，本发明在于利用加速度信号消除光体积变化信号的信号噪声，以提升心跳的计算准确率。It can be understood that the heartbeat detected by the heartbeat detection module 1 can be used in various applications. The present invention uses the acceleration signal to eliminate the signal noise of the photovolume change signal to improve the calculation accuracy of the heartbeat.
图3为本发明实施例的心跳检测方法的流程图，包含下列步骤：以光体积测量装置在检测期间检测皮肤表面以输出光体积变化信号(步骤S10)；以运动感测装置相对所述检测期间输出加速度信号(步骤S11)；以处理单元接收所述光体积变化信号和所述加速度信号(步骤S12)；分别转换所述光体积变化信号和所述加速度信号为第一频域信息和第二频域信息(步骤S13)；根据所述第二频域信息的最大频谱峰值决定去噪参数以对所述第一频域信息去噪(步骤S14)；以及根据去噪后第一频域信息的最大频谱峰值计算心跳(步骤S15)。3 is a flowchart of a heartbeat detection method according to an embodiment of the present invention, which includes the following steps: detecting the skin surface with a photovolume measuring device during detection to output a photovolume change signal (stepS10 ); output an acceleration signal during detection (step S11 ); receive the photo volume change signal and the acceleration signal with a processing unit (step S12 ); convert the photo volume change signal and the acceleration signal into the first frequency domain respectively information and the second frequency domain information (step S13 ); determine denoising parameters according to the maximum spectral peak of the second frequency domain information to denoise the first frequency domain information (step S14 ); and according to the denoising The heartbeat is calculated after the maximum spectral peak value of the first frequency domain information (step S15 ).
请同时参照图1、3、4A、4B、5A、5B和6，接着说明本实施例的实施方式；其中，图4A和4B分别为本发明一实施例的频域光体积变化信号的频谱图和第一频域信息的示意图、图5A和5B分别为本发明一实施例的频域加速度信号的频谱图和第二频域信息的示意图以及图6为本发明实施例的第一频域信息和第二频域信息的示意图。可以了解的是，图4A、4B、5A、5B和6仅用以说明，并非用以限定本发明。Please refer to FIGS. 1, 3, 4A, 4B, 5A, 5B, and 6 at the same time, and then describe the implementation of this embodiment; wherein, FIGS. 4A and 4B are respectively the frequency-domain photovolume change signal spectrum diagrams of an embodiment of the present invention and the schematic diagram of the first frequency domain information, FIGS. 5A and 5B are respectively the spectrogram of the frequency domain acceleration signal and the schematic diagram of the second frequency domain information according to an embodiment of the present invention, and FIG. 6 is the first frequency domain information of the embodiment of the present invention. and a schematic diagram of the second frequency domain information. It can be understood that, FIGS. 4A , 4B, 5A, 5B and 6 are only used for illustration and are not used to limit the present invention.
步骤S10-S11：首先，心跳检测模组1的光体积测量装置10在检测期间检测皮肤表面以输出光体积变化信号Sp；同时，运动感测装置12相对所述检测期间输出加速度信号Sa。为简化说明，以下说明中的光体积变化信号Sp和加速度信号Sa可指经过带通滤波器16滤波后的信号，而不另行说明。必须说明的是，由于所述加速度信号Sa主要用以消除所述光体积变化信号Sp中，因所述光体积测量装置10的感测区与皮肤表面相对运动所产生的噪声，所述光体积变化信号Sp和所述加速度信号Sa较佳相关于大致相同的检测期间以致在所述心跳检测模组1在计算心跳的同时可根据所述加速度信号Sa的信息对所述光体积变化信号Sp的信息进行去噪。StepsS10 -S11 : First, the photovolume measurement device 10 of the heartbeat detection module 1 detects the skin surface during the detection period to output a photovolume change signal Sp; at the same time, the motion sensing device 12 outputs an acceleration signal Sa relative to the detection period . To simplify the description, the photovolume change signal Sp and the acceleration signal Sa in the following description may refer to the signals filtered by the band-pass filter 16 , without further description. It must be noted that, since the acceleration signal Sa is mainly used to eliminate the noise generated by the relative movement of the sensing area of the photovolume measurement device 10 and the skin surface in the photovolume change signal Sp, the photovolume The variation signal Sp and the acceleration signal Sa are preferably related to approximately the same detection period so that the photovolume variation signal Sp can be calculated according to the information of the acceleration signal Sa while the heartbeat detection module 1 is calculating the heartbeat. information is denoised.
步骤S12：接着，所述处理单元14同时接收所述光体积变化信号Sp和所述加速度信号Sa以进行后处理。如图1所示，所述光体积变化信号Sp和所述加速度信号Sa分别输入至所述处理单元14的转换模组140。StepS12 : Next, the processing unit 14 simultaneously receives the photovolume change signal Sp and the acceleration signal Sa for post-processing. As shown in FIG. 1 , the light volume change signal Sp and the acceleration signal Sa are respectively input to the conversion module 140 of the processing unit 14 .
步骤S13：所述处理单元14的所述转换模组140转换所述光体积变化信号Sp为频域光体积变化信号并产生第一组频率索引值和相关的第一组频谱值，其中每一频率索引值对应频谱值。必须说明的是，本实施例的所述转换模组140可利用快速傅立叶转换(FastFourier Transform,FFT)将所述光体积变化信号Sp从时域转换至频域(frequencydomain)以产生所述频域光体积变化信号，但本发明不限于此。其他实施例中，所述转换模组140也可利用离散傅立叶转换(Discrete Fourier Transform,DFT)或其他时域-频域转换方式(也即频谱分析)转换所述光体积变化信号Sp。StepS13 : the conversion module 140 of the processing unit 14 converts the light volume change signal Sp into a frequency domain light volume change signal and generates a first set of frequency index values and a first set of related spectral values, wherein each A frequency index value corresponds to the spectral value. It must be noted that the conversion module 140 of this embodiment can use Fast Fourier Transform (FFT) to convert the photovolume change signal Sp from the time domain to the frequency domain to generate the frequency domain The light volume change signal, but the present invention is not limited thereto. In other embodiments, the conversion module 140 can also use discrete Fourier transform (Discrete Fourier Transform, DFT) or other time-frequency domain conversion methods (ie, spectrum analysis) to convert the photovolume change signal Sp.
可以了解的是，频域光体积变化信号为离散信号以至于所述处理单元14可据以进行数字信号处理。某些实施例中，当所述光体积测量装置10所输出的所述光体积变化信号Sp为连续的时域信号，所述转换模组140先转换所述光体积变化信号Sp为离散的时域信号(例如以取样频率取样所述光体积变化信号Sp)，接着再据以转换为离散的频域信号，但不限于此。其他实施例中，所述转换模组140先转换所述光体积变化信号Sp为连续的频域信号，接着再据以转换为离散的频域信号。It can be understood that the frequency domain photovolume change signal is a discrete signal so that the processing unit 14 can perform digital signal processing accordingly. In some embodiments, when the photovolume change signal Sp output by the photovolume measurement device 10 is a continuous time-domain signal, the conversion module 140 first converts the photovolume change signal Sp into a discrete one. domain signal (for example, the photovolume change signal Sp is sampled at a sampling frequency), and then converted into discrete frequency domain signals, but not limited thereto. In other embodiments, the conversion module 140 first converts the photovolume change signal Sp into a continuous frequency domain signal, and then converts it into a discrete frequency domain signal accordingly.
如前所述，人类心跳的信号频率范围介于0.5Hz至4Hz之间。假设人类心跳的信号频率的最大值为4Hz(对应240次/分)，所述取样频率必须大于8Hz(例如10Hz或20Hz)才能满足奈奎斯特定理(Nyquist Theorem)。在使用快速傅立叶转换的一种实施例中，所述取样频率为20Hz，但不限于此，视所述处理单元14的运算能力而定。As mentioned earlier, the signal frequency range of the human heartbeat is between 0.5Hz and 4Hz. Assuming that the maximum value of the signal frequency of human heartbeat is 4 Hz (corresponding to 240 beats/min), the sampling frequency must be greater than 8 Hz (eg, 10 Hz or 20 Hz) to satisfy the Nyquist Theorem. In an embodiment using fast Fourier transform, the sampling frequency is 20 Hz, but not limited to this, depending on the computing capability of the processing unit 14 .
所述转换模组140利用快速傅立叶转换所述光体积变化信号Sp为所述频域光体积变化信号之后，可产生对应所述频域光体积变化信号的频谱图，如图4A所示，其中，所述频谱图的x轴为快速傅立叶转换的频率索引值(frequency index of FFT)，y轴为频谱强度。本实施例中，图4A的频率索引值以及所对应的频谱强度作为第一组频率索引值和相关的第一组频谱值，也即第一频域信息I1，如图4B所示。After the conversion module 140 converts the light volume change signal Sp into the frequency domain light volume change signal by using fast Fourier transform, it can generate a spectrogram corresponding to the frequency domain light volume change signal, as shown in FIG. 4A , wherein , the x-axis of the spectrogram is the frequency index of FFT (frequency index of FFT), and the y-axis is the spectral intensity. In this embodiment, the frequency index value and the corresponding spectral intensity in FIG. 4A are used as the first group of frequency index values and the related first group of spectral values, that is, the first frequency domain information I1 , as shown in FIG. 4B .
必须说明的是，快速傅立叶转换的频率索引值的数量例如，但不限于，为1024个点(bins)，其中每一频率索引值对应一频率。例如，频率索引值256所对应的频率为(20Hz/1024)×256＝5Hz。可以了解的是，当所述取样频率为20Hz且所述频率索引值的数量为1024个点时，所述第一频域信息I1的频率解析度(frequency resolution)为20Hz/1024＝0.0195Hz。当所述取样频率为固定值时，频率索引值的数量越多则两相邻频率索引值间的频率差越小，以至于所述心跳检测模组1根据频率索引值计算心跳时具有较高的敏感度。It must be noted that the number of frequency index values of the fast Fourier transform is, for example, but not limited to, 1024 bins, wherein each frequency index value corresponds to a frequency. For example, the frequency corresponding to the frequency index value 256 is (20Hz/1024)×256=5Hz. It can be understood that, when the sampling frequency is 20 Hz and the number of the frequency index values is 1024 points, the frequency resolution (frequency resolution) of the first frequency domain information I1 is 20 Hz/1024=0.0195 Hz . When the sampling frequency is a fixed value, the greater the number of frequency index values, the smaller the frequency difference between two adjacent frequency index values, so that the heartbeat detection module 1 has a higher frequency when calculating the heartbeat according to the frequency index value. sensitivity.
必须说明的是，由于人类心跳通常介于30次/分至240次/分之间，所述第一频域信息I1中对应人类心跳的频率索引值范围大约是25至205之间。因此，某些实施例中，所述处理单元14舍弃(或释放)频率索引值小于25和/或大于205以及相关的频谱值以节省系统资源，但不限于此。It must be noted that, since a human heartbeat is usually between 30 beats/min and 240 beats/min, the range of the frequency index value corresponding to the human heartbeat in the first frequency domain informationI1 is approximately between 25 and 205. Therefore, in some embodiments, the processing unit 14 discards (or releases) frequency index values less than 25 and/or greater than 205 and related spectrum values to save system resources, but not limited thereto.
相同地，所述处理单元14中另一转换模组140利用转换所述光体积变化信号Sp的相同方式转换所述加速度信号Sa以产生对应所述加速度信号Sa的频谱图，如图5A所示，并产生第二组频率索引值和相关的第二组频谱值以作为第二频域信息I2，如图5B所示。某些实施例中，所述第二频域信息I2可仅保留所述频率索引值范围(例如25至205)的频率索引值和相关的频谱值。Similarly, another conversion module 140 in the processing unit 14 converts the acceleration signal Sa in the same manner as the photovolume change signal Sp to generate a frequency spectrum corresponding to the acceleration signal Sa, as shown in FIG. 5A . , and generate a second set of frequency index values and a second set of related spectral values as the second frequency domain information I2 , as shown in FIG. 5B . In some embodiments, the second frequency domain information I2 may only retain frequency index values and related spectral values within the frequency index value range (eg, 25 to 205).
步骤S14：在得到所述第二频域信息I2后，峰值萃取模组142根据所述第二频域信息I2中最大频谱峰值PMAX所对应的频率索引值决定参考索引值R。例如，请参照图6，在所述第二组频谱值中，最大频谱值为460，此时所述峰值萃取模组142可识别所述最大频谱峰值PMAX为460并输出所述最大频谱峰值PMAX所对应的频率索引值60至所述计算模组144以作为所述参考索引值R。接着，所述计算模组144计算二分之一倍的所述参考索引值R和两倍的所述参考索引值R。例如，当所述参考索引值R为60时，二分之一倍参考索引值R1/2为30且两倍参考索引值R2为120。可以了解的是，由于所述频率索引值皆代表频率，所述两倍参考索引值R2所对应的频率为所述参考索引值R所对应的频率的倍频，且所述二分之一倍参考索引值R1/2所对应的频率为所述参考索引值R所对应的频率的二分之一倍频。StepS14 : After obtaining the second frequency domain informationI2 , the peak extraction module 142 determines the reference index value R according to the frequency index value corresponding to the maximum spectral peak valuePMAX in the second frequency domain informationI2 . For example, referring to FIG. 6 , in the second set of spectral values, the maximum spectral value is 460. At this time, the peak extraction module 142 can identify the maximum spectral peak PMAX as 460 and output the maximum spectral peak The frequency index value 60 corresponding to PMAX is sent to the calculation module 144 as the reference index value R . Next, the calculation module 144 calculates half the reference index value R and twice the reference index value R. For example, when the reference index value R is 60, the half reference index value R1/2 is 30 and the double reference index value R2 is 120. It can be understood that, since the frequency index values all represent frequencies, the frequency corresponding to the double reference index value R2 is the frequency multiplier of the frequency corresponding to the reference index value R, and the half of the frequency The frequency corresponding to the multiplied reference index value R1 /2 is one-half the frequency corresponding to the reference index value R.
此时，所述计算模组144可根据所述参考索引值R以及所述二分之一倍参考索引值R1/2与所述两倍参考索引值R2至少其中的一者决定去噪参数以对所述第一组频谱值去噪；例如去噪参数可包含索引值R和R1/2、索引值R和R2、或索引值R和R1/2和R2。对所述第一组频谱值去噪指根据所述参考索引值R所得到的所述去噪参数排除所述第一频域信息I1中对应所述参考索引值附近的频谱值。例如，当所述参考索引值R1/2、R和R2分别为30、60和120，所述处理单元14可根据所述参考索引值分别加减预设范围决定去噪范围为20-40、50-70和110-130(也即30±10、60±10和120±10)，并排除所述第一组频谱值中相关所述去噪范围的频谱值以作为对所述第一频域信息I1去噪的方式。某些实施例中，所述预设范围在所述心跳检测模组1出厂前或在所述心跳检测模组1初始化时设定的。At this time, the calculation module 144 may determine denoising according to the reference index value R and at least one of the half reference index value R1/2 and the double reference index value R2 parameters to de-noise the first set of spectral values; for example the de-noising parameters may comprise index values R and R1/2 , index values R and R2 , or index values R and R1/2 and R2 . Denoising the first group of spectral values refers to excluding the spectral values in the first frequency domain information I1 corresponding to the vicinity of the reference index value from the denoising parameter obtained according to the reference index value R. For example, when the reference index values R1/2 , R and R2 are 30, 60, and 120, respectively, the processing unit 14 may determine the denoising range to be 20- 40, 50-70, and 110-130 (that is, 30±10, 60±10, and 120±10), and exclude the spectral values of the first set of spectral values related to the denoising range as a reference to the first set of spectral values. A way of denoising the frequency domain information I1 . In some embodiments, the preset range is set before the heartbeat detection module 1 leaves the factory or when the heartbeat detection module 1 is initialized.
此外，由于所述第二频域信息I2用以供所述处理单元14决定所述去噪参数，某些实施例中，在所述计算模组144从所述峰值萃取模组142得到所述最大频谱峰值PMAX或决定所述去噪参数之后，所述处理单元14舍弃(或释放)所述第二频域信息I2以节省系统资源，但不限于此。In addition, since the second frequency domain information I2 is used for the processing unit 14 to determine the denoising parameter, in some embodiments, the calculation module 144 obtains the result from the peak extraction module 142 . After determining the maximum spectral peak value PMAX or determining the denoising parameter, the processing unit 14 discards (or releases) the second frequency domain information I2 to save system resources, but is not limited thereto.
步骤S15：最后，所述计算模组144根据去噪后第一频域信息的最大频谱峰值计算心跳。更详细的说，在所述计算模组144从所述第一频域信息I1中识别最大频谱峰值时排除所述去噪范围所对应的频谱值(也即第一组频率索引值中频率索引值为20-40、50-70和110-130所对应的频谱值)，例如根据图6的实施例中排除去噪范围所对应的频谱值后(斜线区域表示排除频谱值的范围)，可决定去噪后第一频域信息的最大频谱峰值为930(也即去噪后最大频谱峰值PMAX′)。所述计算模组144根据所述去噪后最大频谱峰值PMAX′所对应频率的频率索引值(也即100)计算所述心跳。如前所述，根据心跳60次/分对应1Hz的情况下，所述心跳为(20/1024)×100×60＝117.19次/分。据此，即使所述光体积测量装置10在非静止状态下输出具有混乱波形的光体积变化信号，所述心跳检测模组1仍可根据所述步骤计算出准确的心跳。StepS15 : Finally, the calculation module 144 calculates the heartbeat according to the maximum spectral peak value of the first frequency domain information after denoising. In more detail, when the calculation module 144 identifies the largest spectral peak from the first frequency domain information I1 , the spectral values corresponding to the denoising range (that is, the frequencies in the first set of frequency index values) are excluded. The index values are the spectral values corresponding to 20-40, 50-70 and 110-130), for example, after excluding the spectral values corresponding to the denoising range in the embodiment of FIG. 6 (the slashed area indicates the range of excluded spectral values) , it can be determined that the maximum spectral peak value of the first frequency domain information after denoising is 930 (that is, the maximum spectral peak value PMAX ′ after denoising). The calculation module 144 calculates the heartbeat according to the frequency index value (ie, 100) of the frequency corresponding to the maximum spectral peak value PMAX ′ after denoising. As described above, in the case where 60 beats/min corresponds to 1 Hz, the heart rate is (20/1024)×100×60=117.19 beats/min. Accordingly, even if the photovolume measuring device 10 outputs a photovolume change signal with a chaotic waveform in a non-stationary state, the heartbeat detection module 1 can still calculate an accurate heartbeat according to the above steps.
必须说明的是，本实施例中，所述计算模组144从所述第一频域信息I1中识别最大频谱峰值时(例如计算心跳时)仅排除(或忽略)所述去噪参数所对应的频谱值而非直接从记忆体中删除所述频谱值，但本发明不限于此。某些实施例中，在步骤S15之前或决定所述去噪参数之后，所述处理单元14可先在记忆体中移除所述第一频域信息I1中相关所述去噪参数的频率索引值和频谱值以节省系统资源。It must be noted that, in this embodiment, when the calculation module 144 identifies the maximum spectral peak from the first frequency domain information I1 (for example, when calculating the heartbeat), only excludes (or ignores) all the parameters of the denoising parameter. The corresponding spectral values are not directly deleted from the memory, but the present invention is not limited thereto. In some embodiments, before stepS15 or after determining the denoising parameter, the processing unit 14 may first remove in the memory the relevant denoising parameter in the first frequency domain informationI1 . Frequency index value and spectrum value to save system resources.
另一方面，为增加计算心跳的准确度，某些实施例中，所述处理单元14将去噪后第一频域信息的所述最大频谱峰值(例如PMAX′)相对应的频率索引值作为心跳索引值NHR(例如100)。接着，再根据所述心跳索引值NHR和所述心跳索引值NHR的相邻频率索引值计算所述心跳。例如，请继续参照图6，当所述心跳索引值NHR为100，所述心跳检测模组1根据所述心跳索引值NHR和所述心跳索引值NHR的相邻两频率索引值99和101以及其所分别对应的频谱值930、890和920计算能量重心为(99×890+100×930+101×920)/(890+930+920)＝100.011。接着，所述计算模组144根据所述能量重心计算所述心跳为(20/1024)×100.011×60＝117.20次/分，但不限于此。所述心跳计算144模组可根据所述心跳索引值和所述心跳索引值的多个相邻的频率索引值(例如4个或6个)计算所述心跳。On the other hand, in order to increase the accuracy of calculating the heartbeat, in some embodiments, the processing unit 14 converts the frequency index value corresponding to the maximum spectral peak value (eg PMAX ′) of the denoised first frequency domain information As the heartbeat index value NHR (eg 100). Next, the heartbeat is calculated according to the heartbeat index value NHR and the adjacent frequency index value of the heartbeat index value NHR . For example, please continue to refer to FIG. 6, when the heartbeat index value NHR is 100, the heartbeat detection module 1 according to the heartbeat index value NHR and the heartbeat index value NHR adjacent two frequency index values 99 and 101 and their corresponding spectral values 930, 890 and 920 respectively, the calculated energy center of gravity is (99×890+100×930+101×920)/(890+930+920)=100.011. Next, the calculation module 144 calculates the heartbeat as (20/1024)×100.011×60=117.20 beats/min according to the energy center of gravity, but is not limited thereto. The heartbeat calculation module 144 may calculate the heartbeat according to the heartbeat index value and a plurality of adjacent frequency index values (eg, 4 or 6) of the heartbeat index value.
由于所述心跳检测模组1在每一检测期间可计算一心跳，所述心跳检测模组1可根据多个检测期间的心跳数值计算所述检测期间的心跳变化趋势并据以估测心跳。某些实施例中，所述处理单元14还包含心跳追踪模组146用以对应多个所述检测期间记录所述心跳的变化趋势。例如，在图6的实施例中，在使用者剧烈运动一时间之后(其中所述时间例如大于至少两倍以上的所述检测期间)，假设所述去噪范围未改变且所述心跳索引值NHR从100变成110，由于所述计算模组144从所述第一频域信息I1中识别最大频谱峰值时会忽略所述去噪范围所对应的频谱值(也即第一组频率索引值中频率索引值为110-130所对应至频谱值)，此时所述心跳索引值NHR会被忽略，所述计算模组144则还可根据所述心跳追踪模组146所记录的所述变化趋势(例如所述时间内所述心跳索引值NHR从100变成110的趋势)估测目前心跳。Since the heartbeat detection module 1 can calculate a heartbeat in each detection period, the heartbeat detection module 1 can calculate the heartbeat change trend during the detection period according to the heartbeat values in a plurality of detection periods and estimate the heartbeat accordingly. In some embodiments, the processing unit 14 further includes a heartbeat tracking module 146 for recording the change trend of the heartbeat during a plurality of detection periods. For example, in the embodiment of FIG. 6 , after the user has been exercising vigorously for a period of time (wherein the time is greater than at least twice the detection period, for example), it is assumed that the denoising range does not change and the heartbeat index value NHR changes from 100 to 110, because the calculation module 144 ignores the spectral value corresponding to the denoising range (that is, the first group of frequencies) when identifying the maximum spectral peak from the first frequency domain information I1 . In the index value, the frequency index value of 110-130 corresponds to the frequency spectrum value), at this time, the heartbeat index value NHR will be ignored, and the calculation module 144 can also be based on the heartbeat tracking module 146. Recorded The change trend (for example, the trend of the heartbeat index value NHR from 100 to 110 within the time period) estimates the current heartbeat.
根据图6实施例的态样中，当所述心跳索引值NHR逐渐地从100变成110，所述计算模组144部分忽略所述去噪范围所对应的频谱值，例如忽略第一组频率索引值中频率索引值为20-40和50-70所对应的频谱值而不忽略110-130所对应的频谱值；也就是说，所述计算模组144可根据心跳索引值NHR的变化将去噪范围110-130视为无效的去噪范围。此时，所述计算模组144则根据所述心跳索引值NHR或去噪后第一频域信息的最大频谱峰值(例如根据第一组频谱值中频谱值为1350所对应的频率索引值为120)计算所述心跳。According to the aspect of the embodiment in FIG. 6 , when the heartbeat index value NHR gradually changes from 100 to 110, the calculation module 144 partially ignores the spectral value corresponding to the denoising range, for example, ignores the first group In the frequency index value, the frequency index values are the spectral values corresponding to 20-40 and 50-70 without ignoring the spectral values corresponding to 110-130; that is, the calculation module 144 can be based on the heartbeat index value NHR Variation treats denoising ranges 110-130 as invalid denoising ranges. At this time, the calculation module 144 is based on the heartbeat index value NHR or the maximum spectral peak value of the first frequency domain information after denoising (for example, according to the frequency index value corresponding to the spectral value 1350 in the first group of spectral values 120) to calculate the heartbeat.
图7为本发明实施例的去噪方法的流程图，包含下列步骤：在检测期间接收光体积变化信号和加速度信号(步骤S21)；转换所述光体积变化信号为频域光体积变化信号并产生具有第一组频率索引值和相关的第一组频谱值的第一频域信息(步骤S22)；转换所述加速度信号为频域加速度信号并产生具有第二组频率索引值和相关的第二组频谱值的第二频域信息(步骤S23)；识别所述第一频域信息中前三大频谱峰值所对应的三个频率索引值和所述第二频域信息中最大频谱峰值所对应的参考索引值(步骤S24)；以及根据所述三个频率索引值和所述参考索引值对所述第一组频谱值进行去噪(步骤S25)。7 is a flowchart of a denoising method according to an embodiment of the present invention, which includes the following steps: receiving a photovolume change signal and an acceleration signal during detection (step S21) ; converting the photovolume change signal into a frequency-domain photovolume change signal and generate first frequency domain information with a first set of frequency index values and a first set of related spectral values (step S22 ); convert the acceleration signal into a frequency domain acceleration signal and generate a second set of frequency index values and related The second frequency domain information of the second group of spectralvalues of the reference index values corresponding to spectral peaks (step S24 ); and performing denoising on the first group of spectral values according to the three frequency index values and the reference index values (step S25 ).
请同时参照图1、6、7和8所示，接着说明本实施例的实施方式；其中图8为本发明一实施例的频率索引值、参考索引值和去噪范围的示意图。1 , 6 , 7 and 8 at the same time, the implementation of this embodiment will be described next; FIG. 8 is a schematic diagram of a frequency index value, a reference index value and a denoising range according to an embodiment of the present invention.
步骤S21：首先，在检测期间接收光体积变化信号Sp和加速度信号Sa。可以了解的是，所述光体积变化信号Sp和所述加速度信号Sa例如分别由光体积测量装置10和运动感测装置12所发出，如图1所示。StepS21 : First, the photovolume change signal Sp and the acceleration signal Sa are received during the detection. It can be understood that, the photo volume change signal Sp and the acceleration signal Sa are respectively emitted by the photo volume measuring device 10 and the motion sensing device 12 , for example, as shown in FIG. 1 .
步骤S22：接着，利用快速傅立叶转换或其他时域-频域的转换方式转换所述光体积变化信号Sp为频域光体积变化信号并产生具有第一组频率索引值和相关的第一组频谱值的第一频域信息I1，例如图6所示。StepS22 : Next, convert the photovolume change signal Sp into a frequency-domain photovolume change signal by using fast Fourier transform or other time domain-frequency domain conversion methods, and generate a first group having a first set of frequency index values and correlations The first frequency domain information I1 of the spectral value is shown, for example, in FIG. 6 .
步骤S23：利用与转换所述光体积变化信号Sp的相同方式转换所述加速度信号Sa为频域加速度信号并产生具有第二组频率索引值和相关的第二组频谱值的第二频域信息I2。本实施例中，由于所述心跳检测模组1具有两个独立的转换模组140，步骤S23与步骤S22可同时进行，但不限于此。StepS23 : Convert the acceleration signal Sa to a frequency domain acceleration signal in the same manner as the photovolume change signal Sp and generate a second frequency domain having a second set of frequency index values and an associated second set of spectral values Information I2 . In this embodiment, since the heartbeat detection module 1 has two independent conversion modules 140, stepS23 and stepS22 can be performed simultaneously, but not limited to this.
可以了解的是，处理单元14可保留所述第一频域信息I1和所述第二频域信息I2中所需要的频率索引值和频谱值信息并储存于记忆单元中，例如仅保留频率索引值0至225和相关的频谱值，但不限于此。It can be understood that the processing unit 14 can retain the frequency index value and spectrum value information required in the first frequency domain informationI1 and the second frequency domain informationI2 and store them in the memory unit, for example, only retain Frequency index values 0 to 225 and associated spectral values, but not limited thereto.
步骤S24：得到所述第一频域信息I1和所述第二频域信息I2之后，所述处理单元14识别所述第一频域信息I1中前三大频谱峰值所对应的三个频率索引值N1、N2、N3和所述第二频域信息I2中最大频谱峰值所对应的参考索引值R。例如，所述第一频域信息I1中前三大频谱峰值所对应的所述三个频率索引值N1、N2和N3分别为58、73和117，且所述第二频域信息I2中最大频谱峰值所对应的所述参考索引值R为120，如图8所示。StepS24 : After obtaining the first frequency domain informationI1 and the second frequency domain informationI2 , the processing unit 14 identifies the first three frequency spectrum peaks corresponding to the first frequency domain informationI1 . Three frequency index values N1 , N2 , N3 and the reference index value R corresponding to the largest spectral peak in the second frequency domain information I2 . For example, the three frequency index values N1 , N2 and N3 corresponding to the top three spectral peaks in the first frequency domain information I1 are 58, 73 and 117 respectively, and the second frequency domain The reference index value R corresponding to the largest spectral peak in the informationI2 is 120, as shown in FIG. 8 .
步骤S25：最后，所述处理单元14根据所述参考索引值R计算二分之一倍参考索引值R1/2和/或两倍参考索引值R2为60和240并决定去噪范围，其中所述去噪范围例如根据所述参考索引值R1/2、R和R2分别加减5以决定且为55-65、115-125和235-245，如图8所示。据此，所述处理单元14根据所述三个频率索引值N1-N3和所述参考索引值R所决定的所述去噪范围对所述频域光体积变化信号进行去噪。StepS25 : Finally, the processing unit 14 calculates the half reference index value R1 /2 and/or double the reference index value R2 as 60 and 240 according to the reference index value R and determines the denoising range , wherein the denoising range is determined by adding or subtracting 5 respectively according to the reference index values R1/2 , R and R2 and is 55-65, 115-125 and 235-245, as shown in FIG. 8 . Accordingly, the processing unit 14 performs denoising on the frequency domain photovolume change signal according to the denoising range determined by the three frequency index values N1 -N3 and the reference index value R.
如前所述，在非静止状态下，所述光体积测量装置10可能会输出不正确的光体积变化信号，以至于所述处理单元14无法根据光体积变化信号直接计算出准确的心跳。因此，通过本实施例的所述步骤S21-S25决定所述去噪范围之后，所述第一频域信息I1中对应所述去噪范围的频率索引值所相关的频谱值可能会是噪声，所述处理单元14可排除所述第一频域信息I1中对应所述去噪范围的频率索引值或相关的频谱值以对所述第一频域信息I1进行去噪。As mentioned above, in a non-stationary state, the photovolume measurement device 10 may output an incorrect photovolume change signal, so that the processing unit 14 cannot directly calculate an accurate heartbeat according to the photovolume change signal. Therefore, after the denoising range is determined through the steps S21 - S25 of this embodiment, the spectral value related to the frequency index value corresponding to the denoising range in the first frequency domain information I1 may be If it is noise, the processing unit 14 may exclude frequency index values or related spectral values corresponding to the denoising range in the first frequency domain informationI1 to perform denoising on the first frequency domain informationI1 .
根据所述去噪方法，其一种应用例如可计算心跳。请继续参照图8，当所述第一频域信息I1的频率索引值N1和N3落入所述去噪范围(也即58和117分别在55-65和115-125之间)而频率索引值N2不在所述去噪范围之内，所述处理单元14可根据所述去噪范围从所述三个频率索引值N1-N3之中决定心跳索引值NHR为73(也即频率索引值N2)。接着，所述处理单元14可根据所述心跳索引值NHR计算所述心跳。例如，所述心跳为(20/1024)×73×60＝85.55次/分。某些实施例中，所述处理单元14根据所述心跳索引值NHR和所述心跳索引值NHR的相邻频率索引值计算所述心跳，其计算方法如前所述，故在此不再赘述。According to the denoising method, one application thereof can be, for example, the calculation of heartbeats. Please continue to refer to FIG. 8 , when the frequency index values N1 and N3 of the first frequency domain information I1 fall within the denoising range (that is, 58 and 117 are between 55-65 and 115-125, respectively) And the frequency index value N2 is not within the denoising range, the processing unit 14 may determine the heartbeat index value NHR to be 73 from the three frequency index values N1 -N3 according to the denoising range (ie frequency index value N2 ). Next, the processing unit 14 may calculate the heartbeat according to the heartbeat index value NHR . For example, the heartbeat is (20/1024)×73×60=85.55 beats/min. In some embodiments, the processing unit 14 calculates the heartbeat according to the heartbeat index value NHR and the adjacent frequency index value of the heartbeat index value NHR . Repeat.
必须说明的是，所述去噪范围以所述频率索引值N1-N3为基准，再加减预设范围(例如加减5)所产生的，其中所述预设范围相关或不相关所述转换模组140的所述取样频率和频率索引值的数量。如前所述，所述取样频率和频率索引值的数量决定频率解析度。某些实施例中，所述预设范围与所述频率解析度呈逆相关，但不限于此。It must be noted that the denoising range is based on the frequency index value N1 -N3 and is generated by adding and subtracting a preset range (for example, adding or subtracting 5), wherein the preset range is related or not. The sampling frequency and the number of frequency index values of the conversion module 140 . As previously mentioned, the sampling frequency and the number of frequency index values determine the frequency resolution. In some embodiments, the preset range is inversely related to the frequency resolution, but not limited thereto.
某些实施例中，所述处理单元14还根据所述去噪范围从所述三个索引值N1-N3的中决定两剩余索引值为58和117(也即索引值N1和N3)。假设所述去噪范围以及所述剩余索引值N1、N3没有改变，在使用者剧烈运动一时间之后，由于所述使用者的心跳上升，相关所述心跳的索引值N2会逐渐靠近索引值N3以至于索引值N2落入去噪范围(也即索引值115-125)之内。此时，所述处理单元14则无法根据所述去噪范围从所述三个索引值的中决定所述心跳索引值NHR。因此，当所述心跳索引值NHR(例如索引值N2)与所述剩余索引值其中的一者(例如索引值N1或N3)的差值小于阈值时，所述处理单元14同样可根据所述心跳索引值NHR对应多个所述检测期间的变化趋势估测所述心跳。In some embodiments, the processing unit 14 further determines two remaining index values from among the three index values N1 -N3 according to the denoising range (that is, the index values N1 and N 3 ).3 ). Assuming that the denoising range and the remaining index values N1 and N3 do not change, after the user has been exercising vigorously for a period of time, the index value N2 related to the heart beat will gradually approach due to the increase of the user's heartbeat. The index value N3 and thus the index value N2 fall within the denoising range (ie, index values 115-125). At this time, the processing unit 14 cannot determine the heartbeat index value NHR from among the three index values according to the denoising range. Therefore, when the difference between the heartbeat index value NHR (eg, index value N2 ) and one of the remaining index values (eg, index value N1 or N3 ) is less than a threshold, the processing unit 14 also The heartbeat can be estimated according to the change trend of the heartbeat index value NHR corresponding to a plurality of the detection periods.
例如，假设所述阈值为10且所述心跳索引值NHR经过所述时间从73变成110，此时所述心跳索引值NHR与所述剩余索引值117(也即频率索引值N3)的差值为7而小于所述阈值，所述处理单元14则根据所述心跳索引值NHR对应多个所述检测期间的所述变化趋势估测所述心跳，其中，根据所述变化趋势和频率索引值计算心跳的方法如前所述，故在此不再赘述。For example, assuming that the threshold value is 10 and the heartbeat index value NHR changes from 73 to 110 after the time, the heartbeat index value NHR and the remaining index value 117 (that is, the frequency index value N3 ) is 7 and is smaller than the threshold, the processing unit 14 estimates the heartbeat according to the change trend of the heartbeat index value NHR corresponding to a plurality of the detection periods, wherein according to the change The method for calculating the heartbeat from the trend and the frequency index value is as described above, so it will not be repeated here.
上述各实施例中，所述光体积测量装置10的所述光体积变化信号Sp和所述运动感测装置12的所述加速度信号Sa并非仅用以计算心跳，所述处理单元14还可根据所述光体积变化信号Sp和所述加速度信号Sa计算使用者的生理状态和运动数据(例如计步、计算跑步或骑车速度以及记录运动时间)，视实际应用而定。In the above embodiments, the photovolume change signal Sp of the photovolume measurement device 10 and the acceleration signal Sa of the motion sensing device 12 are not only used to calculate the heartbeat, the processing unit 14 can also The light volume change signal Sp and the acceleration signal Sa calculate the user's physiological state and exercise data (eg, counting steps, calculating running or cycling speed, and recording exercise time), depending on practical applications.
综上所述，已知心跳检测模组的血氧饱和仪在非静止状态的检测条件下计算心跳时会产生不正确的光体积变化信号，而降低计算心跳的准确度。因此，本发明还提出一种具有去噪功能的心跳检测模组(图1)及其检测(图2)、去噪方法(图7)，其通过加速度信号来决定去噪参数以滤除光体积测量信号中的噪声，藉以提高计算心跳的准确度。To sum up, the oximeter of the known heartbeat detection module will generate an incorrect photovolume change signal when calculating the heartbeat under the non-stationary detection condition, thereby reducing the accuracy of calculating the heartbeat. Therefore, the present invention also proposes a heartbeat detection module with denoising function (FIG. 1) and its detection (FIG. 2) and de-noising method (FIG. 7), which determine de-noising parameters through acceleration signals to filter out light Noise in the volume measurement signal to improve the accuracy of heartbeat calculations.
虽然本发明已通过前述实例披露，但是其并非用以限定本发明，任何本发明所属技术领域中具有通常知识的技术人员，在不脱离本发明的精神和范围内，当可作各种的更动与修改。因此本发明的保护范围当视后附的权利要求所界定的范围为准。Although the present invention has been disclosed through the foregoing examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field to which the present invention pertains can make various modifications without departing from the spirit and scope of the present invention. Move and modify. Therefore, the protection scope of the present invention should be regarded as the scope defined by the appended claims.
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| CN201410522143.9ACN105520726B (en) | 2014-09-30 | 2014-09-30 | Heartbeat detection module and detection and denoising method thereof |
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| CN201410522143.9ACN105520726B (en) | 2014-09-30 | 2014-09-30 | Heartbeat detection module and detection and denoising method thereof |
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| CN201410522143.9AActiveCN105520726B (en) | 2014-09-30 | 2014-09-30 | Heartbeat detection module and detection and denoising method thereof |
| CN201910586579.7AActiveCN110292372B (en) | 2014-09-30 | 2014-09-30 | Detection device |
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