JPH06154179A - Organism information processor - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the calculation accuracy of the non-contact technique for determining the breathing and heart rate of a sleeping person. [Structure] A plurality of sensors 1a, 1 arranged on the bedding 2
b and 1c respond to changes in pressure due to heartbeat and breathing of the sleeping person,
The signal processing circuits 3a, 3b, 3c amplify and filter the response signal, and store the signal value in the storage circuit 6 via the A / D conversion circuit 4. Further, the control circuit 5 calculates the basic period while referring to the stored signal value. With this, the heart rate and respiration rate per unit time are correctly obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact technique for obtaining respiration and heart rate from changes in body surface pressure associated with respiration and heart activity of a sleeping person.

[0002]

2. Description of the Related Art Conventionally, in-patient management of inpatients and the like has been performed by patrols by nurses or monitors by television cameras. As a technology to automate this,
For example, as disclosed in Japanese Patent Laid-Open No. 14928/1990, a method has been devised in which a sleeping person and a display device are paired to monitor the state of the sleeping person. FIG. 6 shows the configuration of the device. Detection unit 1 for detecting body movements of a sleeping person
The cables 2a, 12b, 12c and the display unit 13 are paired and connected by a cable 14.

Regarding the counting of the heart rate, a direct measurement by a doctor or a nurse is generally used, and in the case where the measurement is automatically performed, a method of attaching an electrode or the like to a patient's body has been adopted.

[0004]

In the above-mentioned conventional method, the means of patrol by the nurses imposes a great burden on the nurses. Especially, the patrol work at night is taken up as a social problem due to the shortage of the absolute number of nurses. Has been. In addition, in the unlikely event that a patient's condition suddenly changes between patrols, there is a problem that the discovery will be delayed.

[0005] Although wearing the electrodes on the patient to count the heart rate and the like greatly impairs the freedom of the patient, various noises are included in the biological information from the non-contact sensor such as a piezoelectric element. However, it is impossible to obtain an accurate value for counting the heart rate or the like simply by counting the peaks of the waveform as in the case where the electrodes are directly attached.

Further, when the amount of pressure change on the body surface due to heartbeat activity is small as in an old man, a sufficiently accurate heart rate cannot be obtained by sensing only one point.

The present invention is intended to solve the above problems, and a first object thereof is to reduce stress on a patient by taking in biological information of the patient in a contactless manner without making the patient aware.

A second object is to improve the accuracy of calculation of respiratory rate and heart rate by obtaining the average of information from a plurality of sensors.

A third object is to increase the characteristic amount by adding the respective values of a plurality of sensors in consideration of the individual difference of the signal level of the biometric information and the variation within the individual, and to calculate the respiration rate / heart rate. Is to raise.

[0010]

In order to solve the above-mentioned problems, a biological information processing apparatus according to the present invention comprises a plurality of sensors which are arranged in bedding and which detect a pressure change on the body surface caused by the biological activity of a sleeping person. A / D that has a plurality of signal processing circuits connected to each of the sensors and that amplifies / filters the signals from the sensors, and that has the same number of input channels as the plurality of signal processing circuits and A / D converts the output of the signal processing circuits. D conversion circuit and the A
A storage circuit for storing the conversion result of the A / D conversion circuit;
The A / D conversion circuit is provided with a control circuit for instructing the A / D conversion circuit to start conversion at a constant cycle and calculating the heart rate and respiration rate of the sleeping person from the A / D conversion result stored in the storage circuit.

Further, the control circuit succeeds in the calculation of the basic cycle by the timer means, the basic cycle calculation means connected to the timer means and calculating the basic cycle for each channel of the A / D conversion circuit. It is provided with an average value calculating means for calculating an average value of the basic period of the channel and a converting means for converting the average value calculated by the average value calculating means into a heartbeat / respiration rate per unit time.

Further, the control circuit includes a timer means and an adding means connected to the timer means for adding the A / D conversion results of the channels which satisfy the condition that the A / D conversion result is below a predetermined level for a certain period of time. A basic cycle calculating means for calculating a basic cycle using the addition result of the adding means, and a converting means for converting the basic cycle calculated by the basic cycle calculating means into a heartbeat / respiration rate per unit time Is.

[0013]

With the above structure, in the biological information processing apparatus of the present invention, the sensor electrically responds to the pressure change on the body surface caused by the biological activity of the sleeping person, and the signal processing circuit amplifies and filters the output of the sensor. , The A / D conversion circuit receives the A / D conversion start signal from the control circuit, A / D converts the output from the signal processing circuit, the storage circuit stores the A / D conversion result, and the control circuit stores the A / D conversion result. A conversion start command is output to the D conversion circuit at a constant cycle and the A / D conversion result is read from the storage circuit to calculate the heartbeat / respiration rate per unit time of the sleeping person.

Further, the control circuit refers to the A / D conversion result stored in the storage circuit in the basic period calculation means to calculate the basic period for each channel, and the average value calculation means to calculate the basic period of the channel successfully. The average value of the cycle is calculated, and the conversion means converts the average value into a heartbeat / respiration rate per unit time.

Further, the control circuit refers to the A / D conversion result stored in the storage circuit in the adding means, adds the A / D conversion results for the channels satisfying the condition that is equal to or lower than the level set for a certain time, and then adds the basic cycle. The calculating means calculates a basic cycle for the addition result, and the converting means converts the basic cycle into a heartbeat / respiration rate per unit time.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the first embodiment of the present invention. In this embodiment, the sensors 1a, 1b and 1c are embedded in the bed pad 2, and the signal processing circuits 3a, 3b and 3 are used.
It is connected corresponding to each of c. The sensor 1a is located near the shoulder of the sleeping person, the sensor 1b is located slightly below the scapula, and the sensor 1c is located near the hip. As the sensors 1a to 1c, for example, thin film-processed piezoelectric elements such as polyvinylidene fluoride are used. Signal processing circuit 3
a to 3c are connected to the A / D conversion circuit 4. A /
The D conversion circuit 4 is equipped with an A / D converter, and is configured to receive a conversion start trigger from the control circuit 5 and output the conversion result to the storage circuit 6. A microcomputer is used as the control circuit 5 and is connected to the storage circuit 6. A DRAM or the like is used as the storage circuit 6.

In the above structure, the sensors 1a to 1c generate an electric potential by the pressure change on the body surface caused by the biological activity of the sleeping person. The generated potential is applied to each signal processing circuit 3a-
Amplified at 3c and filtered. At this time, the frequency of the signal passing through the filter is preferably about 0 to 10 Hz in the case of heartbeat, for example. Further, a smoothing process may be added here to efficiently perform the subsequent process. In the first embodiment, the A / D conversion circuit 4 prepares inputs of three channels to receive the outputs of the signal processing circuits 3a to 3c. A
Upon receiving the conversion start trigger from the control circuit 5, the / D conversion circuit 4 converts all inputs of the three channels into digital values and sends them to the storage circuit 6. The memory circuit 6 is the A / D conversion circuit 5
The conversion results sent by the device are stored in order. The control circuit 5 triggers the A / D conversion circuit 4 to start conversion at a constant cycle, reads the A / D conversion results in order from the memory circuit 6, and based on the read data, the heart rate / breathing of the sleeping person. Calculate the number. At this time, the frequency of the conversion start trigger is 20 to 30 Hz in the case of heartbeat. In the case of a heartbeat, the data to be read is the past 5 seconds, and the A / D conversion circuit 4 stores the next 5 seconds of data while performing processing on this data. Therefore, the storage circuit 6 needs to have a capacity for storing data of 3 channels for a total of 10 seconds.

Next, a second embodiment of the present invention will be described. FIG. 2 is a block diagram of a second embodiment of the present invention, in which the control circuit 5 is composed of a timer means 7, a basic period calculation means 8, an average value calculation means 9 and a conversion means 10. The timer means 7 is configured to send a conversion start trigger to the A / D conversion means 4 at a constant cycle and to notify the basic cycle calculation means 8 of the processing start timing every 5 seconds.

FIG. 3 shows a control circuit 5 according to the second embodiment.
5 is a flowchart of the processing of FIG. A series of arithmetic processing in the control circuit 5 is started in response to a processing start command from the timer means 7. First, the variables and arrays used internally are initialized. CH is a control variable for designating a channel, array CY [CH] is a basic period for each channel, and array FLG
[CH] is a flag indicating whether or not the basic period has been successfully calculated for each channel, and MEAN is an average basic period. After initialization, the current channel is confirmed, and if it is an unprocessed channel, the basic cycle is obtained from the A / D conversion result. In calculating the fundamental period, for example, a method using an autocorrelation function can be used. When the fundamental frequency is obtained, 1 is substituted for the value of the flag array. The channel variable CH is incremented and the same processing is repeated for all channels. Next, referring to the flag array, the average value of the basic periods of the channels for which the basic period has been successfully calculated is obtained. Finally, the number of cycles per unit time is calculated from the average value of the basic period.
This can be done by dividing (unit time) by (basic period).

Next, a third embodiment of the present invention will be described. FIG. 4 is a block diagram of the third embodiment of the present invention, in which the control circuit 5 comprises a timer means 7, an adding means 11, a basic period calculating means 8 and a converting means 10. The timer means 7 is configured to send a conversion start trigger to the A / D conversion means 4 at a constant cycle and to notify the basic cycle calculation means 8 of the processing start timing every 5 seconds.

FIG. 5 shows a control circuit 5 according to the third embodiment.
5 is a flowchart of the processing of FIG. A series of arithmetic processing in the control circuit 5 is started in response to a processing start command from the timer means 7. First, the variables and arrays used internally are initialized. CH is a control variable for specifying the channel, D
P is a data designation variable for referring to the A / D converted data, and SUM [DP] is an array showing the addition result of the A / D converted data.

After initialization, the current channel is confirmed, and if it is an unprocessed channel, all the data of that channel are compared with the threshold constant TH. If all data is less than the threshold TH, initialize DP,
The data of that channel is added to the array SUM.
When the addition is completed, or when the data of the channel includes a value equal to or higher than TH, CH is incremented and DP is initialized again to check the next channel. When all channels are processed,
The basic period of the added signals is calculated using the array SUM that stores the addition result. The basic cycle is converted into the heart rate / breathing rate per unit time.

The addition processing is performed in the third embodiment in order to further emphasize the characteristics of the signal. The original waveform of each channel contains many noise components, which hinders the calculation of the fundamental period. However, if signals are added between channels, the
The respiratory component is emphasized, and the basic cycle calculation becomes easy. Further, the comparison with the threshold value TH is performed before the addition is performed. For example, when the channel has a waveform that detects a partial body movement and masks a characteristic component of heartbeat / respiration, it is detected. This is because it is excluded from the addition channel.

In the present invention, whether to detect the heart rate or the respiratory rate can be easily changed by changing the characteristics of the filter of the signal processing circuit 3.

[0026]

As described above, according to the biological information processing apparatus of the present invention, the following effects can be obtained.

1. Since the sleeping person is not made aware of the presence of the sensor, the sleeping person's sleep is not disturbed.

2. Since the average of the information from the plurality of sensors is obtained, the accuracy of calculating the respiratory rate and the heart rate can be improved.

3. By adding the values of a plurality of sensors, it is possible to increase the feature amount of the signal and improve the calculation accuracy of the respiratory rate and heart rate.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a biological information processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a control circuit according to a second embodiment of the present invention.

FIG. 3 is a flowchart of processing in the second embodiment.

FIG. 4 is a block diagram of a control circuit according to a third embodiment of the present invention.

FIG. 5 is a flow chart of processing in a third embodiment.

FIG. 6 is a configuration diagram of a monitor device according to a conventional technique.

[Explanation of symbols]

 1a, 1b, 1c sensor 3a, 3b, 3c signal processing circuit 4 A / D conversion circuit 5 control circuit 6 memory circuit 7 timer means 8 basic period calculation means 9 average value calculation means 10 conversion means 11 addition means

Claims (3)

[Claims] 1. A plurality of sensors, which are arranged in a bedding and detect changes in body surface pressure caused by a living person's biological activity, and a plurality of signals connected to each of the sensors to amplify and filter signals from the sensors. A processing circuit, an A / D conversion circuit that has the same number of input channels as the plurality of signal processing circuits and A / D converts the output of the signal processing circuit, and a memory that stores the conversion result of the A / D conversion circuit. A living body including a circuit and a control circuit for instructing the A / D conversion circuit to start conversion at a constant cycle and for calculating the heart rate and respiration rate of the sleeping person from the A / D conversion result stored in the storage circuit Information processing equipment. 2. A control circuit, a timer means, a basic cycle calculating means which is connected to the timer means and calculates a basic cycle for each channel of an A / D conversion circuit, and the basic cycle calculating means has succeeded in calculating the basic cycle. Average value calculating means for calculating the average value of the basic period of the channel, and the average value calculated by the average value calculating means for the heart rate per unit time
The biological information processing apparatus according to claim 1, further comprising a conversion unit that converts the respiratory rate. 3. A control circuit and a A / D for a channel connected to the timer means and satisfying a condition that an A / D conversion result is below a predetermined level for a certain period of time.
Adding means for adding the conversion results, basic cycle calculating means for calculating a basic cycle using the addition result in the adding means, and the basic cycle calculated by the basic cycle calculating means for the heartbeat / respiration rate per unit time. The biological information processing apparatus according to claim 1, further comprising a conversion unit that converts the biological information.