阅读说明：本技术 一种脑电信号采集装置和方法 (Electroencephalogram signal acquisition device and method ) 是由 杜武松 于 2019-12-21 设计创作，主要内容包括：本发明公开了一种脑电信号采集装置和方法,采用三个采集电极分别粘贴在额头中间、额头左侧或右侧、及同一侧的耳后乳突骨位置,其中额头左侧或右侧的采集电极作为参考电极,通过参考电极输入恒定的交流电流信号到皮肤上；计算另外两个采集电极与参考电极间的阻抗,采用分时的方法检测阻抗与采集脑电信号,实时监测采集电极与皮肤的接触状态,从而保证了采集电极与皮肤的紧密接触,提高了脑电信号采集的准确度,采用二阶低通滤波电路,滤除掉干扰信号,实现了对脑电信号干扰信号的排除,为后续脑电信号的处理提供保障。(The invention discloses an electroencephalogram signal acquisition device and method, wherein three acquisition electrodes are respectively adhered to the middle of a forehead, the left side or the right side of the forehead and the position of the mastoid bone behind the ear at the same side, wherein the acquisition electrode on the left side or the right side of the forehead is used as a reference electrode, and a constant alternating current signal is input to the skin through the reference electrode; the impedance between the other two collecting electrodes and the reference electrode is calculated, the impedance and the electroencephalogram signal are detected by adopting a time-sharing method, and the contact state of the collecting electrodes and the skin is monitored in real time, so that the close contact between the collecting electrodes and the skin is ensured, the accuracy of electroencephalogram signal collection is improved, the interference signals are filtered out by adopting a second-order low-pass filter circuit, the elimination of the electroencephalogram signal interference signals is realized, and the guarantee is provided for the subsequent processing of the electroencephalogram signals.)

1. An electroencephalogram signal acquisition device is characterized in that: the brain electrical signal acquisition device comprises an electroencephalogram signal acquisition electrode, a filter circuit, an analog-to-digital conversion module and a control unit, wherein the electroencephalogram signal acquired by the acquisition electrode is filtered by the filter circuit, input into the analog-to-digital conversion module to be converted into a brain digital signal, and input into the control unit to be calculated.

2. The electroencephalogram signal acquisition device according to claim 1, characterized in that: the collection electrode includes three, is respectively: an electroencephalogram signal positive electrode collecting electrode, an electroencephalogram signal negative electrode collecting electrode and an electroencephalogram signal reference collecting electrode.

3. The electroencephalogram signal acquisition device according to claim 2, characterized in that: each collecting electrode is connected with a filter circuit respectively and used for filtering the electroencephalogram signals collected by each collecting electrode.

4. The electroencephalogram signal acquisition device according to claim 1, characterized in that: the filter circuit comprises a second-order passive RC filter circuit for realizing low-pass filtering; the analog-to-digital conversion module comprises an analog-to-digital conversion IC.

5. The electroencephalogram signal acquisition device according to claim 1, characterized in that: the device also comprises an isolation circuit and an amplitude limiting circuit, wherein the isolation circuit is connected between the analog-to-digital conversion module and the power supply and is used for isolating the influence of the power supply on the acquisition circuit; the amplitude limiting circuit is connected to the rear end of the filter circuit and used for limiting the amplitude of the electroencephalogram signals collected by the collecting electrode.

6. An electroencephalogram signal acquisition method is characterized in that: the method comprises the following steps:

s1, pasting an acquisition electrode in the middle of the forehead as an electroencephalogram signal anode;

s2, pasting an acquisition electrode on the left side or the right side of the forehead as an electroencephalogram signal reference electrode;

s3, pasting an acquisition electrode at the position of the mastoid bone behind the ear on the same side of the reference electrode as the cathode of the electroencephalogram signal;

s4, respectively calculating the impedance between the positive electrode of the electroencephalogram signal and the electroencephalogram signal reference electrode, and the impedance between the negative electrode of the electroencephalogram signal and the electroencephalogram signal reference electrode;

s5, comparing the impedance value with a set value, and confirming whether the collecting electrode is in good contact with the skin; if the contact is good, the electroencephalogram signals are collected, and if the contact is not good, the adjustment is carried out until the requirements are met.

7. The electroencephalogram signal acquisition method according to claim 6, characterized in that: the reference electrode flows constant alternating current into the skin, the voltage between the positive pole of the electroencephalogram signal and the negative pole of the electroencephalogram signal is detected under the excitation of the constant alternating current, and the impedance value is obtained through calculation.

8. The electroencephalogram signal acquisition method according to claim 6, characterized in that: if the impedance value is less than the set value, the contact is good; and if the impedance value is larger than or equal to the set value, alarming.

9. The electroencephalogram signal acquisition method according to claim 6, characterized in that: in one acquisition cycle, impedance detection and electroencephalogram signal acquisition are carried out in a time-sharing mode, after impedance detection, a first set time period is delayed for signal stabilization, then electroencephalogram signal acquisition is carried out, and then a second set time period is delayed for signal stabilization.

10. The electroencephalogram signal acquisition method according to claim 9, characterized in that: and the electroencephalogram signal at a certain period of time after the acquisition period of the electroencephalogram signal in the previous period is copied and is used for supplementing the loss of the electroencephalogram signal at the impedance detection and delay waiting period of the period so as to ensure that the electroencephalogram signal is continuous.

Technical Field

The invention relates to the technical field of electroencephalogram signals, in particular to an electroencephalogram signal acquisition device and method.

Background

An electroencephalogram (EEG) is a potential activity generated by brain nerves, contains rich brain activity information, and is a main signal source for anesthesia depth monitoring research. However, because the electroencephalogram (EEG) is very weak and is in the microvolt (uV) level, the EEG is easily interfered by the external environment, and if the interfered signals are not processed, the EEG can greatly affect the measurement of parameters related to the anesthesia depth. Among these interference sources are power supply noise, power frequency noise and electrode wire shaking and pulling interference introduced by the circuit of the anesthesia depth monitoring device, and signal interference such as body movement, Electrocardiogram (ECG), Electromyogram (EMG) and eye movement of the patient himself. If the interference signals are not processed correspondingly, the weak electroencephalogram (EEG) signals are submerged, so that the EEG signals cannot be acquired.

Electroencephalogram measurement is a common medical diagnosis method, brain activity information is obtained by collecting electroencephalogram signals, and measurement of the electroencephalogram signals also provides an important electroencephalogram signal source for wearable equipment. The measurement of the brain electrical signal is that brain electrical electrodes are placed at a certain position of the head, weak brain electrical signals are collected, and the brain electrical signals are collected, amplified, processed and recorded by brain electrical equipment such as an electroencephalograph.

The existing electroencephalogram signal acquisition device mostly adopts an annular structure, has poor adaptability to different head shapes, and simultaneously has the defects that the electrode plates are not tightly contacted with the skin, so that the measurement accuracy of the electroencephalogram signals is poor, and the processing result of the subsequent electroencephalogram signals is not ideal.

Therefore, how to realize good contact between the collecting electrode and the skin and improve the collecting accuracy of the electroencephalogram signals is a problem to be solved urgently at present.

Disclosure of Invention

The invention aims to provide an electroencephalogram signal acquisition device and method, wherein three acquisition electrodes are adopted, one of the acquisition electrodes is used as a reference electrode, a constant alternating current signal is input to the skin through the reference electrode, the impedance between the other two acquisition electrodes and the reference electrode is acquired and calculated, the impedance and the acquired electroencephalogram signal are detected by adopting a time-sharing method, and the contact state of the acquisition electrodes and the skin is monitored in real time, so that the close contact between the acquisition electrodes and the skin is ensured, the accuracy of electroencephalogram signal acquisition is improved, and the guarantee is provided for the subsequent electroencephalogram signal processing.

The above object of the present invention is achieved by the following technical solutions:

an electroencephalogram signal acquisition device comprises an electroencephalogram signal acquisition electrode, a filter circuit, an analog-to-digital conversion module and a control unit, wherein electroencephalogram signals acquired by the acquisition electrode are filtered by the filter circuit, input to the analog-to-digital conversion module to be converted into brain digital signals, and input to the control unit to be calculated.

The invention is further configured to: the collection electrode includes three, is respectively: an electroencephalogram signal positive electrode collecting electrode, an electroencephalogram signal negative electrode collecting electrode and an electroencephalogram signal reference collecting electrode.

The invention is further configured to: each collecting electrode is connected with a filter circuit respectively and used for filtering the electroencephalogram signals collected by each collecting electrode.

The invention is further configured to: the filter circuit comprises a second-order passive RC filter circuit and realizes low-pass filtering.

The invention is further configured to: the analog-to-digital conversion module comprises an analog-to-digital conversion IC.

The invention is further configured to: the device also comprises an isolation circuit which is connected between the analog-digital conversion module and the power supply and used for isolating the influence of the power supply on the acquisition circuit.

The invention is further configured to: the amplitude limiting circuit is connected to the rear end of the filter circuit and used for limiting the amplitude of the electroencephalogram signals collected by the collecting electrode.

The above object of the present invention is also achieved by the following technical solutions:

an electroencephalogram signal acquisition method comprises the following steps:

s1, pasting an acquisition electrode in the middle of the forehead as an electroencephalogram signal anode;

s2, pasting an acquisition electrode on the left side or the right side of the forehead as an electroencephalogram signal reference electrode;

s3, pasting an acquisition electrode at the position of the mastoid bone behind the ear on the same side of the reference electrode as the cathode of the electroencephalogram signal;

s4, respectively calculating the impedance between the positive electrode of the electroencephalogram signal and the electroencephalogram signal reference electrode, and the impedance between the negative electrode of the electroencephalogram signal and the electroencephalogram signal reference electrode;

s5, comparing the impedance value with a set value, and confirming whether the collecting electrode is in good contact with the skin; if the contact is good, the electroencephalogram signals are collected, and if the contact is not good, the adjustment is carried out until the requirements are met.

The invention is further configured to: the reference electrode flows constant alternating current into the skin, the voltage between the positive pole of the electroencephalogram signal and the negative pole of the electroencephalogram signal is detected under the excitation of the constant alternating current, and the impedance value is obtained through calculation.

The invention is further configured to: if the impedance value is less than the set value, the contact is good; and if the impedance value is larger than or equal to the set value, alarming.

The invention is further configured to: in one acquisition cycle, impedance detection and electroencephalogram signal acquisition are carried out in a time-sharing mode, after impedance detection, a first set time period is delayed for signal stabilization, then electroencephalogram signal acquisition is carried out, and then a second set time period is delayed for signal stabilization.

The invention is further configured to: and the electroencephalogram signal of a certain period of the previous cycle is copied for supplementing the loss of the electroencephalogram signal of the next period of impedance detection and delay waiting period, so that the electroencephalogram signal is continuous.

Compared with the prior art, the invention has the beneficial technical effects that:

1. according to the method, the three collecting electrodes are arranged on the same side of the forehead and the head, the middle electrode is used as a reference electrode, constant alternating current is input, and the impedance between the other two collecting electrodes is measured, so that whether the collecting electrodes are in close contact with the skin or not is realized, and the collecting accuracy of electroencephalogram signals is ensured;

2. furthermore, the method and the device adopt a second-order low-pass filter circuit to filter out interference signals, so that elimination of electroencephalogram signal interference signals is realized;

3. furthermore, the analog-digital conversion IC ADS1299 is adopted, pre-amplification is not needed, and analog-digital conversion is directly carried out after filtering, so that the circuit structure is reduced, and the cost is reduced;

4. furthermore, the method and the device adopt a time-sharing mode to collect the impedance and the electroencephalogram signals respectively, detect the impedance change in real time, check when the impedance exceeds a set value in time, and avoid errors in the collection process.

Drawings

FIG. 1 is a schematic diagram of a circuit structure of an electroencephalogram signal acquisition device according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an electroencephalogram signal acquisition method according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a low pass filter circuit according to an embodiment of the present invention;

fig. 4 is a schematic diagram of an analog-to-digital conversion circuit according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.