TW201438669A - Detecting method and apparatus for blood oxygen saturation - Google Patents
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本發明關於醫療器械領域,特別是一種血氧飽和度測量裝置,尤其是一種在具有運動干擾條件下的血氧飽和度檢測方法及裝置。 The invention relates to the field of medical instruments, in particular to a blood oxygen saturation measuring device, in particular to a blood oxygen saturation detecting method and device under the condition of motion interference.
基於紅外光和近紅外光的雙波長非侵入式血氧飽和度檢測技術已被大量應用於臨床。非侵入式血氧飽和度檢測技術基於動脈血液的光的吸收量隨動脈波動而變化的原理,在透射式血氧飽和度檢測中,當透光區域動脈血管搏動時,動脈血液對光的吸收量將隨之變化,稱為交流量;而皮膚、肌肉、骨骼等其他組織對光的吸收是恒定不變的,稱為直流量。採用雙波長法測量血氧飽和度,需要先計算比率值R,然後通過定標曲線的方式來計算出血氧飽和度。 Dual-wavelength non-invasive oximetry detection technology based on infrared light and near-infrared light has been widely used in clinical practice. The non-invasive blood oxygen saturation detection technology is based on the principle that the absorption of light in arterial blood varies with arterial fluctuation. In the transmission oxygen saturation detection, when the arterial blood vessels in the light-transmitting region are pulsating, the absorption of light by the arterial blood The amount will change accordingly, called the amount of exchange; while the absorption of light by other tissues such as skin, muscles, bones, etc. is constant, called the amount of DC. To measure blood oxygen saturation using the dual-wavelength method, the ratio value R needs to be calculated first, and then the hemorrhagic oxygen saturation is calculated by means of a calibration curve.
比率R的計算公式如下所示:
目前對於R值的計算一般採用波峰-波峰法。由於脈搏波波形具有週期性,在每個週期內都存在一個最大值和一個最小值,在該週期內 尋找兩組光的最大值和最小值就能計算兩組光的交流量,從而計算出該週期的R值。但是,如果脈搏波信號中帶有較強的干擾信號時,則在尋找脈搏波波形最大值和最小值時極易出現錯誤。特別是在救護車等實際臨床時,由於抖動導致手指與感測器之間發生位移,使脈搏波波形中出現大量干擾波形,在計算時就會導致最大值和最小值找尋錯誤。為解決運動干擾帶來的血氧計算錯誤問題,通常的做法是首先消除相關干擾雜訊,然後再尋找消噪後脈搏波波形的最大值和最小值。 At present, the peak-to-peak method is generally used for the calculation of the R value. Since the pulse wave waveform has periodicity, there is a maximum value and a minimum value in each cycle during which the cycle By finding the maximum and minimum values of the two sets of light, the amount of alternating light of the two sets of light can be calculated to calculate the R value of the period. However, if there is a strong interfering signal in the pulse wave signal, it is prone to errors when looking for the maximum and minimum values of the pulse wave waveform. Especially in the actual clinical situation such as ambulance, due to the displacement between the finger and the sensor due to the jitter, a large number of interference waveforms appear in the pulse wave waveform, and the maximum and minimum values are found in the calculation. In order to solve the problem of blood oxygen calculation error caused by motion interference, the common practice is to first eliminate the relevant interference noise, and then find the maximum and minimum values of the pulse waveform after denoising.
關於消除脈搏波信號中運動干擾的信號處理方法,在很多文 獻中都有相關報導,譬如獨立成分分析法、適應性濾波對消法、卡爾曼濾波法、經驗模態分解法等。其中,已經成功商業化的方法中,Masimo公司在專利US5482036中所描述的適應性濾波對消法效果較好,其主要關鍵在於採用兩組光信號巧妙形成一個雜訊參考信號,並以此代入適應性濾波消除器模組,同時還包含一個回歸濾波器。 Signal processing method for eliminating motion interference in pulse wave signals, in many articles There are related reports in the offering, such as independent component analysis, adaptive filtering cancellation, Kalman filtering, and empirical mode decomposition. Among them, among the methods that have been successfully commercialized, the adaptive filtering method described by Masimo in the patent US Pat. No. 5,482,036 is better. The main key is to use two sets of optical signals to form a noise reference signal and substitute it. The adaptive filter canceller module also includes a regression filter.
參考第1圖,為習知技術中的一種基於適應性濾波對消法來進行血氧的計算的流程圖,其過程一般包括以下幾個步驟:S110:對原始信號進行預處理;例如進行低通濾波消除高頻雜訊和基線漂移處理以及消除直流波動等。 Referring to FIG. 1 , a flow chart of calculating blood oxygen based on adaptive filtering cancellation method in the prior art, the process generally includes the following steps: S110: pre-processing the original signal; for example, performing low Pass-through filtering eliminates high-frequency noise and baseline drift processing as well as eliminating DC fluctuations.
S120:利用兩組光信號形成雜訊參考;為形成雜訊參考,一般需經過比較複雜的邏輯判斷與計算,例如包括傅立葉頻譜分析等。 S120: Using two sets of optical signals to form a noise reference; in order to form a noise reference, generally requires complicated logic judgment and calculation, for example, including Fourier spectrum analysis.
S130:利用步驟S120所形成的雜訊參考進行適應性濾波去噪處理,以消除運動雜訊;這個過程的運算需經過反覆運算迴圈計算,運算量比較大,其中包括適應性濾波器和回歸濾波兩個部分。 S130: performing adaptive filtering and denoising processing by using the noise reference formed in step S120 to eliminate motion noise; the operation of this process needs to be calculated by repeating the operation loop, and the calculation amount is relatively large, including adaptive filter and regression. Filter the two parts.
S140:利用經過步驟S130處理過的兩組信號尋找極值,利用公式(1)以計算血氧值。 S140: Find the extreme value by using the two sets of signals processed in step S130, and calculate the blood oxygen level by using formula (1).
但此項技術的不足之處在於:由於涉及到適應性濾波以及傅立葉轉換等運算,因此對硬體平臺要求較高,實現起來相對比較複雜,從而導致成本較高。而目前血氧飽和度測量設備的小型化已成為一種趨勢,同時要求有較高的規格性能,對於在小型化血氧儀中實施上述演算法流程比較困難。 However, the shortcoming of this technology is that due to the adaptive filtering and Fourier transform operations, the requirements for the hardware platform are relatively high, and the implementation is relatively complicated, resulting in high cost. At present, the miniaturization of blood oxygen saturation measuring equipment has become a trend, and at the same time, high specification performance is required, and it is difficult to implement the above algorithm flow in a miniaturized oximeter.
故,的確需要一種技術方案,能夠解決由於演算法流程複雜、對硬體平臺要求較高,在小型化血氧儀中實施比較困難的問題。 Therefore, it is indeed necessary to have a technical solution, which can solve the problem that it is difficult to implement in the miniaturized oximeter due to the complicated process of the algorithm and the high requirements on the hardware platform.
本發明所要解決的技術問題是,提供一種能夠消除運動干擾,保持較高精度的血氧飽和度測量的方法及裝置,實現運動干擾下的血氧飽和度準確測量,使硬體平臺小型化,從而使可擕式血氧儀也能實現抗運動干擾功能。 The technical problem to be solved by the present invention is to provide a method and a device for measuring blood oxygen saturation which can eliminate motion interference and maintain high precision, and realize accurate measurement of blood oxygen saturation under motion interference, thereby miniaturizing the hardware platform. Therefore, the portable oximeter can also achieve anti-motion interference function.
為了解決上述問題,本發明提供了一種信號的降噪方法,包括如下步驟:(1)計算原始信號中分離出的交流信號的初始時域能量;(2)根據預設的一第一濾波範圍對該交流信號進行濾波;(3)計算濾波後的該交流信號的第一時域能量;(4)判斷該第一時域能量與該初始時域能量的比值是否大於一預先設定的第一閥值,若小於或等於該第一閥值,則完成信號的降噪。 In order to solve the above problems, the present invention provides a signal denoising method, comprising the steps of: (1) calculating an initial time domain energy of an isolated AC signal in an original signal; and (2) determining a first filtering range according to a preset Filtering the AC signal; (3) calculating a first time domain energy of the filtered AC signal; (4) determining whether a ratio of the first time domain energy to the initial time domain energy is greater than a predetermined first The threshold, if less than or equal to the first threshold, completes the noise reduction of the signal.
為了解決上述問題,本發明還提供了一種血氧飽和度檢測方 法,包括如下步驟:(A)分別採集紅光和近紅外光波段的脈搏波時域信號,並分離出交流信號;(B)採用本發明該的信號的降噪方法分別對紅光和近紅外光波段的脈搏波時域信號中的交流信號進行降噪,消除該交流信號中的運動干擾能量;(C)計算降噪後的紅光交流信號時域能量和近紅外光交流信號時域能量的比值;(D)根據所獲得的時域能量比值計算血氧飽和度。 In order to solve the above problems, the present invention also provides an oxygen saturation detecting method. The method comprises the following steps: (A) separately acquiring a pulse wave time domain signal of a red light and a near-infrared light band, and separating an alternating current signal; (B) using the noise reduction method of the signal of the invention to respectively red light and near The AC signal in the pulse wave time domain signal of the infrared light band is used for noise reduction to eliminate the motion interference energy in the AC signal; (C) Calculating the time domain energy of the red light AC signal after noise reduction and the time domain of the near infrared light AC signal The ratio of energy; (D) Calculate blood oxygen saturation based on the obtained time domain energy ratio.
可選的,步驟(A)進一步包括:分別對該紅光和近紅外光 波段的脈搏波時域信號進行消除基線漂移處理、消除高頻雜訊處理以及去直流處理,從而分離出相應的交流信號。 Optionally, the step (A) further comprises: respectively respectively, the red light and the near infrared light The pulse wave time domain signal of the band performs the elimination of the baseline drift processing, the elimination of the high frequency noise processing, and the de-DC processing, thereby separating the corresponding AC signal.
可選的,若該第一時域能量與該初始時域能量的比值大於該 第一閥值,則步驟(B)進一步包括:(B1)縮小濾波範圍,並根據縮小後的濾波範圍對該交流信號再次進行濾波;(B2)計算經步驟(B1)濾波後的該交流信號的第二時域能量;(B3)判斷該第二時域能量與該初始時域能量的比值是否大於一預先設定的第二閥(threshold)值,其中該第二閥值小於該第一閥值,若小於或等於該第二閥值則完成信號的降噪,消除了該交流信號中的運動干擾能量,否則返回執行步驟(B1)。 Optionally, if the ratio of the first time domain energy to the initial time domain energy is greater than the The first threshold, the step (B) further comprises: (B1) reducing the filtering range, and filtering the AC signal again according to the reduced filtering range; (B2) calculating the AC signal filtered by the step (B1) a second time domain energy; (B3) determining whether the ratio of the second time domain energy to the initial time domain energy is greater than a predetermined second threshold value, wherein the second threshold is less than the first valve The value, if less than or equal to the second threshold, completes the noise reduction of the signal, eliminating the motion interference energy in the AC signal, otherwise returning to the execution step (B1).
為了解決上述問題,本發明還提供了一種血氧飽和度檢測裝 置,包括依次相連的採集模組、消除運動干擾能量模組、比值計算模組以及飽和度計算模組;該採集模組用於分別採集紅光和近紅外光波段的脈搏波時域信號,並分離出交流信號;該消除運動干擾能量模組用於採用本發明該的信號的降噪方法分別對紅光和近紅外光波段的脈搏波時域信號中的交流信號進行降噪,消除該交流信號中的運動干擾能量;該比值計算模組用於計算降噪後的紅光交流信號時域能量和近紅外光交流信號時域能量的 比值;該飽和度計算模組用於根據所獲得的時域能量比值計算血氧飽和度。 In order to solve the above problems, the present invention also provides an oxygen saturation detecting device. The device includes a collection module, a motion cancellation energy module, a ratio calculation module and a saturation calculation module, which are sequentially connected to each other; the acquisition module is configured to separately collect pulse wave time domain signals in the red and near infrared bands, And separating the AC signal; the canceling the motion interference energy module is used for denoising the AC signal in the pulse wave time domain signal of the red and near infrared light bands by using the noise reduction method of the signal of the invention, and eliminating the noise signal The motion interference energy in the AC signal; the ratio calculation module is used to calculate the time domain energy of the red-light AC signal after noise reduction and the time domain energy of the near-infrared light AC signal Ratio; the saturation calculation module is configured to calculate blood oxygen saturation based on the obtained time domain energy ratio.
可選的,該採集模組進一步用於:分別對該紅光和近紅外光 波段的脈搏波時域信號進行消除基線漂移處理、消除高頻雜訊處理以及去直流處理,從而分離出相應的交流信號。 Optionally, the acquisition module is further configured to: respectively, the red light and the near infrared light The pulse wave time domain signal of the band performs the elimination of the baseline drift processing, the elimination of the high frequency noise processing, and the de-DC processing, thereby separating the corresponding AC signal.
可選的,該消除運動干擾能量模組進一步包括依次相連的第 一計算單元、濾波單元、第二計算單元以及判斷單元;該第一計算單元用於計算該交流信號的初始時域能量;該濾波單元用於根據預設的一第一濾波範圍對該交流信號進行濾波;該第二計算單元用於計算濾波後的該交流信號的第一時域能量;該判斷單元用於判斷該第一時域能量與該初始時域能量的比值是否大於一預先設定的第一閥值,若小於或等於該第一閥值,則完成信號的降噪,消除了該交流信號中的運動干擾能量。 Optionally, the motion cancellation energy module further includes a first connected a calculation unit, a filtering unit, a second calculation unit, and a determination unit; the first calculation unit is configured to calculate an initial time domain energy of the AC signal; the filtering unit is configured to: the AC signal according to a preset first filter range Performing filtering; the second calculating unit is configured to calculate a first time domain energy of the filtered AC signal; the determining unit is configured to determine whether a ratio of the first time domain energy to the initial time domain energy is greater than a preset The first threshold value, if less than or equal to the first threshold value, completes noise reduction of the signal, eliminating motion interference energy in the AC signal.
若該第一時域能量與該初始時域能量的比值大於該第一閥 值,則該濾波單元進一步用於縮小濾波範圍,並根據縮小後的濾波範圍對該交流信號再次進行濾波;該第二計算單元進一步用於計算經再次濾波後的該交流信號的第二時域能量;該判斷單元進一步用於判斷該第二時域能量與該初始時域能量的比值是否大於一預先設定的第二閥值,其中該第二閥值小於該第一閥值,若小於或等於該第二閥值則完成信號的降噪,消除了該交流信號中的運動干擾能量,否則調用該濾波單元進一步縮小濾波範圍後再次濾波。 If the ratio of the first time domain energy to the initial time domain energy is greater than the first valve And the filtering unit is further configured to reduce the filtering range, and filter the AC signal again according to the reduced filtering range; the second calculating unit is further configured to calculate the second time domain of the re-filtered AC signal The determining unit is further configured to determine whether the ratio of the second time domain energy to the initial time domain energy is greater than a predetermined second threshold, wherein the second threshold is less than the first threshold, if less than or Equal to the second threshold, the noise reduction of the signal is completed, and the motion interference energy in the AC signal is eliminated. Otherwise, the filtering unit is called to further reduce the filtering range and then filter again.
本發明的優點在於,採用時域能量的方法來判斷是否具有運 動干擾,並通過時域能量比值計算交流比值。當運動干擾頻率大於心跳所對應頻率時,血氧飽和度計算具有較高精度,能實現被測者運動情況下血 氧飽和度的較高精度的測量,同時提高了計算效率;本發明所需實施演算法相對比較簡單,對硬體平臺要求不高,有利於硬體平臺小型化,因此可以在小型可擕式血氧儀中實現抗運動干擾功能。 The invention has the advantage that the method of time domain energy is used to judge whether there is a transport Dynamic interference, and calculate the AC ratio through the time domain energy ratio. When the motion interference frequency is greater than the frequency corresponding to the heartbeat, the blood oxygen saturation calculation has higher precision, and the blood can be achieved under the movement of the subject. The higher precision measurement of oxygen saturation improves the calculation efficiency at the same time; the required implementation algorithm of the invention is relatively simple, the requirements on the hardware platform are not high, and the hardware platform is small, so that it can be used in a small portable type. Anti-motion interference function is realized in the oximeter.
S110‧‧‧對原始信號進行預處理 S110‧‧‧Preprocessing the original signal
S120‧‧‧利用兩組光信號形成雜訊參考 S120‧‧‧Using two sets of optical signals to form a noise reference
S130‧‧‧利用步驟S120所形成的雜訊參考進行自我調整濾波去噪處理,以消除運動雜訊 S130‧‧‧Using the noise reference formed in step S120 for self-adjusting filtering and denoising to eliminate motion noise
S140‧‧‧利用經過步驟S130處理過的兩路信號尋找極值,並計算血氧值 S140‧‧‧Using the two signals processed in step S130 to find the extreme value and calculate the blood oxygen value
S210‧‧‧計算原始信號中分離出的所述交流信號的初始時域能量E S210‧‧‧ Calculate the initial time domain energy E of the AC signal separated from the original signal
S220‧‧‧根據預設的一第一濾波範圍對所述交流信號進行濾波 S220‧‧‧ filtering the AC signal according to a preset first filtering range
S230‧‧‧計算濾波後的交流信號的第一時域能量E1 S230‧‧‧ Calculate the first time domain energy E1 of the filtered AC signal
S240‧‧‧E1/E是否大於第一閾值M1 Whether S240‧‧‧E1/E is greater than the first threshold M1
S250‧‧‧縮小濾波範圍,並根據縮小後的濾波範圍對所述交流信號進行濾波 S250‧‧‧ Reduce the filtering range and filter the AC signal according to the reduced filtering range
S260‧‧‧計算經步驟S250濾波後的交流信號的第二時域能量E2 S260‧‧‧ Calculating the second time domain energy E2 of the AC signal filtered by step S250
S270‧‧‧E2/E是否大於第二閾值M2 Whether S270‧‧‧E2/E is greater than the second threshold M2
S410‧‧‧分別採集紅光和近紅外光波段的脈搏波時域信號,並分離出交流信號 S410‧‧‧ separately collect pulse wave time domain signals in the red and near-infrared bands, and separate the AC signals
S421‧‧‧計算所述交流信號的初始時域能量E S421‧‧‧ Calculate the initial time domain energy E of the AC signal
S422‧‧‧根據預設的一第一濾波範圍對所述交流信號進行濾波 S422‧‧‧ filtering the AC signal according to a preset first filtering range
S423‧‧‧計算濾波後的所述交流信號的第一時域能量E1 S423‧‧‧ Calculating the first time domain energy E1 of the filtered AC signal
S424‧‧‧判斷E1與E的比值是否大於一預先設定的第一閾值M1,若E1/E小於或等於M1,則干擾頻率能量被消除,信號的降噪完成 S424‧‧‧Resolve whether the ratio of E1 to E is greater than a preset first threshold M1. If E1/E is less than or equal to M1, the interference frequency energy is eliminated and the signal noise reduction is completed.
S430‧‧‧計算降噪後的紅光交流信號時域能量和近紅外光交流信號時域能量的比值 S430‧‧‧ Calculate the ratio of the time domain energy of the red-light AC signal and the time-domain energy of the near-infrared light AC signal after noise reduction
S440‧‧‧根據所獲得的時域能量比值計算血氧飽和度 S440‧‧‧ Calculate blood oxygen saturation based on the obtained time domain energy ratio
61‧‧‧採集模組 61‧‧‧ Acquisition module
62‧‧‧消除運動干擾能量模組 62‧‧‧Removal of motion interference energy modules
621‧‧‧第一計算單元 621‧‧‧First calculation unit
622‧‧‧濾波單元 622‧‧‧Filter unit
623‧‧‧第二計算單元 623‧‧‧Second calculation unit
624‧‧‧判斷單元 624‧‧‧judging unit
63‧‧‧比值計算模組 63‧‧‧ ratio calculation module
64‧‧‧飽和度計算模組 64‧‧‧Saturation calculation module
第1圖是習知技術中的一種基於適應性濾波對消法來進行血氧的計算的流程圖。 Figure 1 is a flow chart of a conventional technique for calculating blood oxygen based on an adaptive filtering cancellation method.
第2圖是本發明該信號的降噪方法的具體實施方式的流程圖。 Fig. 2 is a flow chart showing a specific embodiment of the noise reduction method of the signal of the present invention.
第3圖是帶有運動干擾的脈搏波頻譜示意圖。 Figure 3 is a schematic diagram of the pulse wave spectrum with motion interference.
第4圖是本發明該血氧飽和度檢測方法的具體實施方式的流程圖。 Fig. 4 is a flow chart showing a specific embodiment of the blood oxygen saturation detecting method of the present invention.
第5A-5D圖是本發明該血氧飽和度檢測方法的一實施例的信號波形圖,其中第5A-5B圖分別為原始紅光信號以及原始近紅外光信號的波形圖,第5C-5D圖分別為紅光交流信號以及近紅外光交流信號的波形圖。 5A-5D is a signal waveform diagram of an embodiment of the blood oxygen saturation detecting method of the present invention, wherein the 5A-5B graph is a waveform diagram of the original red light signal and the original near-infrared light signal, respectively, 5C-5D The figure is a waveform diagram of a red light AC signal and a near-infrared light AC signal.
第6圖是本發明之血氧飽和度檢測裝置的具體實施方式的結構示意圖。 Fig. 6 is a schematic structural view showing a specific embodiment of the blood oxygen saturation detecting device of the present invention.
下面結合附圖對本發明提供的血氧飽和度檢測方法及裝置的具體實施方式做詳細說明。 The specific embodiments of the blood oxygen saturation detecting method and apparatus provided by the present invention will be described in detail below with reference to the accompanying drawings.
首先結合附圖給出本發明該信號的降噪方法的具體實施方式。 First, a specific embodiment of the noise reduction method of the signal of the present invention will be given with reference to the accompanying drawings.
第2圖所示是本具體實施方式提供的信號的降噪方法的流程 圖,接下來對第2圖所示的步驟做詳細說明。 Figure 2 is a flow chart showing the noise reduction method of the signal provided by the specific embodiment. Figure, next to the steps shown in Figure 2 will be described in detail.
S210:計算原始信號中分離出的交流信號的初始時域能量 E。 S210: Calculating initial time domain energy of the separated AC signal in the original signal E.
採集原始信號,對所採集到的原始信號進行消除基線漂移處 理、消除高頻雜訊處理以及去直流處理,從而分離出相應的交流信號;其中,該原始信號可以為脈搏波時域信號。對於一段脈搏波時域信號,除了理想脈搏波信號外,還包括背景光雜訊、基線漂移等低頻雜訊、電磁干擾等高頻雜訊、以及可能的各種抖動雜訊等。對於背景光雜訊,一般通過光遮罩和資料獲取中背景光扣除等方式可消除,而對於低頻和高頻雜訊,採用通常低通濾波、高通濾波或帶通濾波即能消除。因此,首先對脈搏波時域信號進行消除基線漂移處理和消除高頻雜訊處理,然後再進行去直流處理,剩下部分即為脈搏波時域信號的交流部分。 Acquire the original signal and eliminate the baseline drift of the original signal collected The high frequency noise processing and the DC processing are eliminated to separate the corresponding AC signal; wherein the original signal can be a pulse wave time domain signal. For a pulse wave time domain signal, in addition to the ideal pulse wave signal, it also includes low-frequency noise such as background noise, baseline drift, high-frequency noise such as electromagnetic interference, and possible various types of jitter noise. For background light noise, it can be eliminated by means of light mask and background light subtraction in data acquisition, and low frequency and high frequency noise can be eliminated by low-pass filtering, high-pass filtering or band-pass filtering. Therefore, the pulse wave time domain signal is first eliminated from the baseline drift processing and the high frequency noise processing is eliminated, and then the DC processing is performed, and the remaining portion is the alternating portion of the pulse wave time domain signal.
S220:根據預設的一第一濾波範圍對該交流信號進行濾 波。該濾波包括帶通濾波、低通濾波以及低通濾波與帶通濾波相結合的濾波方式。 S220: Filter the AC signal according to a preset first filtering range. wave. The filtering includes band pass filtering, low pass filtering, and a filtering method combining low pass filtering and band pass filtering.
S230:計算濾波後的該交流信號的第一時域能量E1。 S230: Calculate the first time domain energy E1 of the filtered AC signal.
S240:判斷該第一時域能量E1與該初始時域能量E的比值是 否大於一預先設定的第一閥值M1,若E1/E小於或等於該第一閥值M1,則干擾頻率能量被消除,信號的降噪完成。 S240: determining that the ratio of the first time domain energy E1 to the initial time domain energy E is If it is greater than a preset first threshold M1, if E1/E is less than or equal to the first threshold M1, the interference frequency energy is eliminated, and the noise reduction of the signal is completed.
在運動干擾情況下,脈搏波時域交流信號中的能量主要來自 兩個部分:理想脈搏波信號能量以及干擾頻率能量。由於運動干擾頻率大 於心跳所對應頻率,可以通過高階低通濾波或帶通濾波或者低通濾波與帶通濾波相結合的方式消除運動干擾頻率。在一段脈搏波時域交流信號內如果在經過濾波消除干擾頻率後,該段信號內脈搏波時域能量會大幅度減小。因此,可以比較濾波前後時域能量的大小,如果在濾波後時域能量大幅減小但同時保持相對較大的值,則說明時域能量中運動干擾的部分被消除,同時理想脈搏波信號能量被保留。 In the case of motion interference, the energy in the pulse wave time domain AC signal mainly comes from Two parts: the ideal pulse wave signal energy and the interference frequency energy. Due to the high frequency of motion interference At the frequency corresponding to the heartbeat, the motion interference frequency can be eliminated by combining high-order low-pass filtering or band-pass filtering or low-pass filtering and band-pass filtering. In a pulse wave time domain AC signal, if the interference frequency is removed after filtering, the time domain energy of the pulse wave in the segment signal is greatly reduced. Therefore, the magnitude of the time domain energy before and after filtering can be compared. If the time domain energy is greatly reduced after filtering but maintains a relatively large value, the part of the motion interference in the time domain energy is eliminated, and the ideal pulse wave signal energy is eliminated. Be kept.
在本具體實施方式中,若該第一時域能量E1與該初始時域 能量E的比值大於該第一閥值M1,則該方法還至少包括步驟S250-S270。 In this embodiment, if the first time domain energy E1 and the initial time domain The ratio of the energy E is greater than the first threshold M1, and the method further includes at least steps S250-S270.
S250:縮小濾波範圍,並根據縮小後的濾波範圍對該交流 信號再次進行濾波。 S250: narrowing the filtering range and communicating according to the reduced filtering range The signal is filtered again.
S260:計算經步驟S250濾波後的該交流信號的第二時域能 量E2。 S260: Calculate the second time domain energy of the AC signal filtered by step S250. The amount is E2.
S270:判斷該第二時域能量E2與該初始時域能量E的比值是 否大於一預先設定的第二閥值M2,其中該第二閥值M2小於該第一閥值M1。若E2/E小於或等於該第二閥值M2則干擾頻率能量被消除信號的降噪完成;否則返回執行步驟S250。 S270: determining that the ratio of the second time domain energy E2 to the initial time domain energy E is No greater than a predetermined second threshold value M2, wherein the second threshold value M2 is less than the first threshold value M1. If E2/E is less than or equal to the second threshold value M2, the noise reduction of the interference frequency energy is cancelled by the signal; otherwise, the process returns to step S250.
在實際處理中,由於對理想脈搏波信號頻率以及干擾頻率都 未知,僅僅採用一次濾波處理很難消除運動干擾影響,可以採用逐次逼近的方法來消除可能的運動干擾。即,若E1/E大於該第一閥值M1,則縮小濾波範圍以及縮小相應的閥值,重新對交流信號進行濾波,並對濾波後的時域能量進行比較,直到時域能量中運動干擾的部分被消除。 In actual processing, due to the ideal pulse wave signal frequency and the interference frequency Unknown, it is difficult to eliminate the influence of motion interference by using only one filtering process, and the successive approximation method can be used to eliminate possible motion interference. That is, if E1/E is greater than the first threshold M1, the filtering range is reduced and the corresponding threshold is reduced, the AC signal is re-filtered, and the filtered time domain energy is compared until the motion interference in the time domain energy The part is eliminated.
接下來結合附圖給出本發明該血氧飽和度檢測方法的具體 實施方式。 Next, the specific method of the blood oxygen saturation detecting method of the present invention is given with reference to the accompanying drawings. Implementation.
在血氧飽和度計算中,主要在於兩組光信號交流比值的確 定。本發明提出採用時域能量的方法來判斷是否具有運動干擾,並通過時域能量比值計算交流比值。將脈搏波時域交流信號經傅立葉轉換到頻域,當存在運動干擾的情況下,脈搏波信號頻譜圖如圖3所示。 In the calculation of blood oxygen saturation, mainly in the two groups of optical signal exchange ratio is indeed set. The present invention proposes a method of using time domain energy to determine whether there is motion interference, and calculates an AC ratio by a time domain energy ratio. The pulse wave time domain AC signal is Fourier transformed into the frequency domain. When there is motion interference, the spectrum of the pulse wave signal is shown in Fig. 3.
本發明的基本思想是:根據脈搏波時域信號的特徵和傅立葉 轉換的定義,兩組脈搏波時域信號頻譜上心跳頻率處振幅之比,近似等於兩組脈搏波時域信號的交流值比值。因此,進行R值計算時,可以採用兩組脈搏波時域信號頻譜上心跳頻率處振幅之比來替代交流量比值,從而可以避免在脈搏波時域信號中尋找最大值和最小值。對於兩組理想脈搏波信號,心跳頻率處振幅之比與心跳頻率2倍頻、3倍頻處振幅之比理論上相等。 The basic idea of the invention is: according to the characteristics of the pulse wave time domain signal and Fourier The definition of the transition, the ratio of the amplitudes of the heartbeat frequencies on the spectrum of the two sets of pulse wave time domain signals, is approximately equal to the ratio of the AC values of the time domain signals of the two sets of pulse waves. Therefore, when calculating the R value, the ratio of the amplitudes of the heartbeat frequencies on the spectrum of the two sets of pulse wave time domain signals can be used instead of the AC ratio, so that the maximum and minimum values can be avoided in the pulse wave time domain signal. For the two sets of ideal pulse wave signals, the ratio of the amplitude at the heartbeat frequency is theoretically equal to the ratio of the amplitude of the heartbeat frequency of 2 times and 3 times.
同時,根據傅立葉轉換性質之Rayleigh定理:
其中f(s)為f(t)的傅立葉轉換,E為能量,這裡定義 為時域能量,定義心跳頻率處紅光信號頻譜振幅與近紅外光頻譜振幅之比為M,在理想脈搏波情況下有如下關係(其中Red表示紅光,IRed表示近紅外光): Where f ( s ) is the Fourier transform of f ( t ), E is energy, defined here For the time domain energy, the ratio of the spectral amplitude of the red light signal to the amplitude of the near-infrared light spectrum at the heartbeat frequency is defined as M, and in the case of an ideal pulse wave, the relationship is as follows (where Red represents red light and IRed represents near-infrared light):
利用公式(2)則有:
因此在理想脈搏波情況下可以在時域上直接採用兩組光時 域能量之比來近似替代兩組光信號的交流值比值。但是,在帶有運動干擾的條件下,顯然直接採用時域能量之比不可行,如果通過信號的降噪能消除時域能量中運動干擾的影響,則可以採用時域能量之比近似替代兩組光信號的交流值比值進行R值計算。 Therefore, in the case of an ideal pulse wave, two sets of light can be directly used in the time domain. The ratio of domain energies approximately replaces the ratio of the alternating values of the two sets of optical signals. However, under the condition of motion interference, it is obvious that the direct ratio of time domain energy is not feasible. If the noise reduction of the signal can eliminate the influence of motion interference in the time domain energy, the time domain energy ratio can be used to replace the two. The R value is calculated by the ratio of the AC value of the group optical signal.
第4圖所示是本具體實施方式該血氧飽和度檢測方法的流程 圖,接下來對第4圖所示的步驟做詳細說明。 Figure 4 is a flow chart showing the blood oxygen saturation detecting method of the present embodiment. Figure, next to the steps shown in Figure 4 will be described in detail.
S410:分別採集紅光和近紅外光波段的脈搏波時域信號, 並分離出交流信號。 S410: acquiring pulse wave time domain signals in the red and near infrared bands, respectively. And separate the AC signal.
對於一段脈搏波時域信號,除了理想脈搏波信號外,還包括 背景光雜訊、基線漂移等低頻雜訊、電磁干擾等高頻雜訊、以及可能的各種抖動雜訊等;如第5A-5B圖所示,其中第5A圖為原始紅光信號的波形圖,第5B圖為原始近紅外光信號的波形圖。對於背景光雜訊,一般通過光遮罩和資料獲取中背景光扣除等方式可消除,而對於低頻和高頻雜訊,採用通常低通濾波、高通濾波或帶通濾波即能消除。因此,這裡應首先對脈搏波時域信號進行消除基線漂移處理和消除高頻雜訊處理,然後再進行去直流處理,剩下部分即為脈搏波時域信號的交流部分,包括紅光交流部分和近紅外光交流部分;如第5C-5D圖所示,其中第5C圖為紅光交流信號的波形圖,第5D圖為近紅外光交流信號的波形圖。在進行去直流處理時,可以同時獲取脈搏波時域信號中紅光和近紅外光信號的直流量。 For a pulse wave time domain signal, in addition to the ideal pulse wave signal, Low-frequency noise such as background noise, baseline drift, high-frequency noise such as electromagnetic interference, and possible various types of jitter noise; as shown in Figure 5A-5B, Figure 5A shows the waveform of the original red light signal. Figure 5B is a waveform diagram of the original near-infrared light signal. For background light noise, it can be eliminated by means of light mask and background light subtraction in data acquisition, and low frequency and high frequency noise can be eliminated by low-pass filtering, high-pass filtering or band-pass filtering. Therefore, the pulse wave time domain signal should be eliminated first and the high frequency noise processing should be eliminated, and then the DC processing should be performed. The remaining part is the AC part of the pulse wave time domain signal, including the red light communication part. And the near-infrared light communication part; as shown in FIG. 5C-5D, wherein FIG. 5C is a waveform diagram of a red-light AC signal, and FIG. 5D is a waveform diagram of a near-infrared light AC signal. When performing DC processing, the DC quantities of the red and near-infrared light signals in the pulse wave time domain signal can be simultaneously acquired.
繼續參考第4圖,在步驟S421中:計算該交流信號的初始時 域能量E。該交流信號包括紅光交流信號和近紅外光交流信號。 With continued reference to FIG. 4, in step S421: calculating the initial time of the AC signal Domain energy E. The AC signal includes a red light AC signal and a near infrared light AC signal.
S422:根據預設的一第一濾波範圍對該交流信號進行濾波。 S422: Filter the AC signal according to a preset first filtering range.
由於運動干擾頻率大於心跳所對應頻率,該濾波可以採用帶通濾波、低通濾波以及低通濾波與帶通濾波相結合的濾波方式。本具體實施方式以帶通濾波為例,該第一濾波範圍可以設置為[0.5Hz,4.16Hz](對應脈搏跳動次數為每分鐘30-250次)。 Since the motion interference frequency is greater than the frequency corresponding to the heartbeat, the filtering may use bandpass filtering, low-pass filtering, and a combination of low-pass filtering and bandpass filtering. In this embodiment, band pass filtering is taken as an example, and the first filtering range can be set to [0.5 Hz, 4.16 Hz] (corresponding to the number of pulse beats is 30-250 times per minute).
S423:計算濾波後的該交流信號第一時域能量E1。 S423: Calculate the first time domain energy E1 of the filtered AC signal.
S424:判斷該第一時域能量E1與該初始時域能量E的比值是否大於一預先設定的第一閥值M1,若E1/E小於或等於該第一閥值M1,則干擾頻率能量被消除,信號的降噪完成。其中,M1可以根據實際試驗測量結果設置。 S424: Determine whether the ratio of the first time domain energy E1 to the initial time domain energy E is greater than a preset first threshold value M1. If E1/E is less than or equal to the first threshold value M1, the interference frequency energy is Eliminate, the noise reduction of the signal is completed. Among them, M1 can be set according to the actual test results.
步驟S421-S424所描述的方法即採用了第2圖對應實施方式該的信號的降噪方法分別對紅光和近紅外光波段的脈搏波時域信號中的交流信號進行降噪,從而消除該交流信號中的運動干擾能量。 The method described in steps S421-S424 uses the noise reduction method of the signal corresponding to the embodiment of FIG. 2 to respectively reduce the noise of the alternating current signal in the pulse wave time domain signal of the red and near infrared light bands, thereby eliminating the The motion in the AC signal interferes with energy.
在實際處理中,由於對心跳頻率以及干擾頻率都未知,僅採用一次高階低通或帶通濾波很難消除運動干擾影響。在本具體實施方式中,若該第一時域能量E1與該初始時域能量E的比值大於該第一閥值M1,則消除該交流信號中的運動干擾能量還需執行以下步驟(第4圖中未示出)。 In the actual processing, since the heartbeat frequency and the interference frequency are unknown, it is difficult to eliminate the motion interference effect by using only one high-order low-pass or band-pass filtering. In this embodiment, if the ratio of the first time domain energy E1 to the initial time domain energy E is greater than the first threshold value M1, the following steps are performed to eliminate the motion interference energy in the AC signal (4th) Not shown in the figure).
B1):縮小濾波範圍,並根據縮小後的濾波範圍對該交流信號再次進行濾波。例如,縮小帶通濾波範圍為[0.5Hz,3Hz]。 B1): The filtering range is reduced, and the AC signal is filtered again according to the reduced filtering range. For example, the bandpass filtering range is [0.5 Hz, 3 Hz].
B2):計算經步驟B1濾波後的該交流信號的第二時域能量E2。 B2): Calculating the second time domain energy E2 of the AC signal filtered by the step B1.
B3):判斷該第二時域能量E2與該初始時域能量E的比值是 否大於一預先設定的第二閥值M2,其中M2小於M1。若E2/E小於或等於M2,則說明干擾頻率能量被消除,信號的降噪完成;若E2/E大於M2,則返回執行步驟B1進一步縮小濾波範圍,再次進行濾波來消除可能的運動干擾能量。 B3): determining that the ratio of the second time domain energy E2 to the initial time domain energy E is No greater than a predetermined second threshold M2, where M2 is less than M1. If E2/E is less than or equal to M2, the interference frequency energy is eliminated, and the signal noise reduction is completed. If E2/E is greater than M2, return to step B1 to further reduce the filtering range, and perform filtering again to eliminate possible motion interference energy. .
在運動干擾情況下,脈搏波時域交流信號中的能量主要來自 兩個部分:①理想脈搏波信號能量(其中心跳頻率能量占主導,二倍頻及以上部分能量占比少);②干擾頻率能量。當運動干擾頻率大於心跳頻率時,則可以通過高階低通濾波或帶通濾波或者低通濾波與帶通濾波相結合的方式消除運動干擾頻率。在一段脈搏波時域交流信號內如果在經過濾波消除干擾頻率後,會大幅度減小,根據公式(2)即可知該段信號內脈搏波時域波形經過濾波後,其時域能量會大幅度減小。因此,可以比較在濾波前後時域能量的大小,如果在濾波後時域能量大幅減小但同時保持相對較大的值,則說明時域能量中運動干擾的部分被消除同時心跳頻率處能量被保留。 In the case of motion interference, the energy in the pulse wave time domain AC signal mainly comes from two parts: 1 ideal pulse wave signal energy (the center hop frequency energy is dominant, and the second frequency and above part of the energy is less); 2 interference frequency energy. When the motion interference frequency is greater than the heartbeat frequency, the motion interference frequency can be eliminated by high-order low-pass filtering or band-pass filtering or low-pass filtering combined with band-pass filtering. In the pulse wave time domain AC signal, after filtering to eliminate the interference frequency, It will be greatly reduced. According to formula (2), the time domain energy of the pulse wave time domain waveform in the segment signal is filtered. Will be greatly reduced. Therefore, the magnitude of the time domain energy before and after filtering can be compared. If the time domain energy is greatly reduced after filtering but maintains a relatively large value, then the part of the motion interference in the time domain energy is eliminated and the energy at the heartbeat frequency is Reserved.
繼續參考第4圖,在步驟S430中:計算降噪後的紅光交流信 號時域能量和近紅外光交流信號時域能量的比值。當兩組光信號經過同樣的濾波處理後,則兩組光剩下時域能量之比值即近似等於兩組光信號的交流值比值之平方。 Continuing to refer to FIG. 4, in step S430: calculating a red-light exchange letter after noise reduction The ratio of the time domain energy to the time domain energy of the near-infrared light AC signal. When the two sets of optical signals are subjected to the same filtering process, the ratio of the remaining time domain energy of the two sets of light is approximately equal to the square of the ratio of the alternating current values of the two sets of optical signals.
S440:根據所獲得的時域能量比值計算血氧飽和度。 S440: Calculate blood oxygen saturation according to the obtained time domain energy ratio.
根據所獲得的兩組光信號的時域能量比值,即可近似計算出 兩組光信號的交流值比值;再根據步驟S410中去直流處理同時獲取的兩組光信號的直流量,即可根據公式(1)計算出比率R,進而計算出血氧飽和 度;其中根據比率R計算出血氧飽和度可以採用習知的技術手段,此處不再贅述。 According to the time-domain energy ratio of the two sets of optical signals obtained, the approximate calculation can be calculated. The ratio of the exchange value of the two sets of optical signals; according to the DC quantity of the two sets of optical signals acquired simultaneously by the DC processing in step S410, the ratio R can be calculated according to formula (1), thereby calculating the hemorrhagic oxygen saturation. The degree of hemorrhage oxygen saturation calculated according to the ratio R can be determined by a conventional technique, and will not be described herein.
本發明採用時域能量的方法來判斷是否具有運動干擾,並通 過時域能量比值計算交流比值。當運動干擾頻率大於心跳所對應頻率時,血氧飽和度計算具有較高精度,能實現被測者運動情況下血氧飽和度的較高精度的測量,同時提高了計算效率;本發明該方法所需實施演算法相對比較簡單,對硬體平臺要求不高,有利於硬體平臺小型化,因此可以在小型可擕式血氧儀中實現抗運動干擾功能。 The invention adopts the method of time domain energy to judge whether there is motion interference, and The overtime domain energy ratio calculates the AC ratio. When the motion interference frequency is greater than the frequency corresponding to the heartbeat, the blood oxygen saturation calculation has higher precision, which can achieve higher precision measurement of blood oxygen saturation under the motion of the subject, and improve the calculation efficiency; the method of the invention The required implementation algorithm is relatively simple, and the requirements on the hardware platform are not high, which is beneficial to the miniaturization of the hardware platform, so that the anti-motion interference function can be realized in the small portable oximeter.
接下來結合附圖給出本發明該血氧飽和度檢測裝置的具體 實施方式。 Next, the specificity of the blood oxygen saturation detecting device of the present invention will be given with reference to the accompanying drawings. Implementation.
第6圖所示是本具體實施方式該血氧飽和度檢測裝置的結 構示意圖。該裝置包括依次相連的採集模組61、消除運動干擾能量模組62、比值計算模組63以及飽和度計算模組64。 Figure 6 is a diagram showing the junction of the blood oxygen saturation detecting device of the present embodiment. Schematic diagram. The device includes an acquisition module 61, a motion cancellation energy module 62, a ratio calculation module 63, and a saturation calculation module 64 that are sequentially connected.
該採集模組61用於分別採集紅光和近紅外光波段的脈搏波 時域信號,並分離出交流信號。該採集模組61分別對該紅光和近紅外光波段的脈搏波時域信號進行消除基線漂移處理、消除高頻雜訊處理以及去直流處理,從而分離出相應的交流信號。在進行去直流處理時,可以同時獲取脈搏波時域信號中紅光和近紅外光信號的直流量。 The acquisition module 61 is configured to separately collect pulse waves in the red and near infrared bands Time domain signal and separate AC signal. The acquisition module 61 respectively performs baseline drift processing, high frequency noise processing, and de-DC processing on the pulse wave time domain signals of the red and near-infrared light bands, thereby separating corresponding AC signals. When performing DC processing, the DC quantities of the red and near-infrared light signals in the pulse wave time domain signal can be simultaneously acquired.
該消除運動干擾能量模組62用於採用本發明該的信號的降 噪方法分別對紅光和近紅外光波段的脈搏波時域信號中的該交流信號進行降噪,消除該交流信號中的運動干擾能量。 The motion cancellation interference energy module 62 is used to reduce the signal of the present invention. The noise method respectively denoises the AC signal in the pulse wave time domain signal of the red and near-infrared light bands, and eliminates the motion interference energy in the AC signal.
在本具體實施方式中,該消除運動干擾能量模組62進一步 包括依次相連的第一計算單元621、濾波單元622、第二計算單元623以及判斷單元624。 In this embodiment, the motion cancellation interference energy module 62 further The first calculation unit 621, the filtering unit 622, the second calculation unit 623, and the determination unit 624 are sequentially connected.
該第一計算單元621用於計算該交流信號的初始時域能量 E;該交流信號包括紅光交流信號和近紅外光交流信號。 The first calculating unit 621 is configured to calculate initial time domain energy of the alternating current signal E; the AC signal includes a red light AC signal and a near infrared light AC signal.
該濾波單元622用於根據預設的一第一濾波範圍對該交流 信號進行濾波。由於運動干擾頻率大於心跳所對應頻率,該濾波可以採用帶通濾波、低通濾波以及低通濾波與帶通濾波相結合的濾波方式。本具體實施方式以帶通濾波為例,該第一濾波範圍可以設置為[0.5Hz,4.16Hz]。 The filtering unit 622 is configured to exchange the first filtering range according to a preset The signal is filtered. Since the motion interference frequency is greater than the frequency corresponding to the heartbeat, the filtering may use bandpass filtering, low-pass filtering, and a combination of low-pass filtering and bandpass filtering. In this embodiment, band pass filtering is taken as an example, and the first filtering range can be set to [0.5 Hz, 4.16 Hz].
該第二計算單元623用於計算濾波後的該交流信號第一時 域能量E1。 The second calculating unit 623 is configured to calculate the first time of the filtered AC signal Domain energy E1.
該判斷單元624用於判斷該第一時域能量E1與該初始時域 能量E的比值是否大於一預先設定的第一閥值M1,若小於或等於該第一閥值M1,則說明干擾頻率能量被消除,信號的降噪完成。其中,M1可以根據實際試驗測量結果設置。 The determining unit 624 is configured to determine the first time domain energy E1 and the initial time domain. Whether the ratio of the energy E is greater than a predetermined first threshold M1, if less than or equal to the first threshold M1, the interference frequency energy is eliminated, and the noise reduction of the signal is completed. Among them, M1 can be set according to the actual test results.
在實際處理中,由於對心跳頻率以及干擾頻率都未知,僅採 用一次濾波很難消除運動干擾影響;若該第一時域能量E1與該初始時域能量E1比值大於該第一閥值M1,則本具體實施方式中,該濾波單元622進一步用於:縮小濾波範圍,並根據縮小後的濾波範圍對該交流信號再次進行濾波。例如,縮小帶通濾波範圍為[0.5Hz,3Hz]。該第二計算單元623進一步用於:計算經再次濾波後的該交流信號的第二時域能量E2。該判斷單元624進一步用於:判斷該第二時域能量E2與該初始時域能量E的比值是否大於一預先設定的第二閥值M2,其中M2小於M1。若E2/E小於或等 於M2,則說明干擾頻率能量被消除,信號的降噪完成;否則調用該濾波單元622進一步縮小濾波範圍,再次進行濾波直至消除可能的運動干擾。 In actual processing, since the heartbeat frequency and the interference frequency are unknown, only It is difficult to eliminate the influence of the motion interference by using the primary filtering; if the ratio of the first time domain energy E1 to the initial time domain energy E1 is greater than the first threshold value M1, in the specific embodiment, the filtering unit 622 is further configured to: reduce Filtering the range and filtering the AC signal again according to the reduced filtering range. For example, the bandpass filtering range is [0.5 Hz, 3 Hz]. The second calculating unit 623 is further configured to: calculate the second time domain energy E2 of the re-filtered AC signal. The determining unit 624 is further configured to: determine whether the ratio of the second time domain energy E2 to the initial time domain energy E is greater than a preset second threshold M2, where M2 is less than M1. If E2/E is less than or equal At M2, the interference frequency energy is eliminated, and the noise reduction of the signal is completed; otherwise, the filtering unit 622 is called to further reduce the filtering range, and the filtering is performed again until the possible motion interference is eliminated.
該比值計算模組63用於計算降噪後的紅光交流信號時域能 量和近紅外光交流信號時域能量的比值。當兩組光信號經過同樣的濾波處理後,則兩組光剩下時域能量之比值即近似等於兩組光信號的交流值比值之平方。 The ratio calculation module 63 is configured to calculate the time domain energy of the red-light AC signal after noise reduction The ratio of the amount and the time-domain energy of the near-infrared light AC signal. When the two sets of optical signals are subjected to the same filtering process, the ratio of the remaining time domain energy of the two sets of light is approximately equal to the square of the ratio of the alternating current values of the two sets of optical signals.
該飽和度計算模組64用於根據所獲得的時域能量比值計算 血氧飽和度。根據所獲得的兩組光信號的時域能量比值,即可近似計算出兩組光信號的交流值比值;再根據該採集模組61去直流處理同時獲取的兩組光信號的直流量,即可根據公式(1)計算出比率R,進而計算出血氧飽和度;其中根據比率R計算出血氧飽和度可以採用習知的技術手段,此處不再贅述。 The saturation calculation module 64 is configured to calculate according to the obtained time domain energy ratio Blood oxygen saturation. According to the time-domain energy ratio of the two sets of optical signals obtained, the ratio of the alternating current values of the two sets of optical signals can be approximated; and according to the DC quantity of the two sets of optical signals acquired by the acquisition module 61 to the DC processing, The ratio R can be calculated according to the formula (1), and the hemorrhage oxygen saturation can be calculated. The calculation of the hemorrhage oxygen saturation according to the ratio R can be performed by a conventional technique, and will not be described herein.
以上該僅是本發明的最佳實施方式,應當指出,對於熟悉本 技術之人員,在不脫離本發明原理的前提下,還可以做出若干改進和潤飾,這些改進和潤飾也應視為本發明的保護範圍。 The above is only the preferred embodiment of the present invention, it should be noted that The skilled person will be able to make several modifications and refinements without departing from the principles of the invention, and such modifications and refinements are also considered to be within the scope of the invention.
S410‧‧‧分別採集紅光和近紅外光波段的脈搏波時域信號,並分離出交流信號 S410‧‧‧ separately collect pulse wave time domain signals in the red and near-infrared bands, and separate the AC signals
S421‧‧‧計算所述交流信號的初始時域能量E S421‧‧‧ Calculate the initial time domain energy E of the AC signal
S422‧‧‧根據預設的一第一濾波範圍對所述交流信號進行濾波 S422‧‧‧ filtering the AC signal according to a preset first filtering range
S423‧‧‧計算濾波後的所述交流信號的第一時域能量E1 S423‧‧‧ Calculating the first time domain energy E1 of the filtered AC signal
S424‧‧‧判斷E1與E的比值是否大於一預先設定的第一閾值M1,若E1/E小於或等於M1,則干擾頻率能量被消除,信號的降噪完成 S424‧‧‧Resolve whether the ratio of E1 to E is greater than a preset first threshold M1. If E1/E is less than or equal to M1, the interference frequency energy is eliminated and the signal noise reduction is completed.
S430‧‧‧計算降噪後的紅光交流信號時域能量和近紅外光交流信號時域能量的比值 S430‧‧‧ Calculate the ratio of the time domain energy of the red-light AC signal and the time-domain energy of the near-infrared light AC signal after noise reduction
S440‧‧‧根據所獲得的時域能量比值計算血氧飽和度 S440‧‧‧ Calculate blood oxygen saturation based on the obtained time domain energy ratio
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