JP2008259745A - Biological signal processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sleep measuring device, preventing wrong determination on whether or not the amplification factor of an amplifier is suitable or not according to a biological signal of a frequency band except a predetermined frequency band corresponding to a heart beat or the like. <P>SOLUTION: This biological signal processor includes: a sensor 5 for detecting a biological signal corresponding to the sleep state; a variable amplifier 41 for amplifying the biological signal; a filter 42 for extracting a signal of the predetermined frequency band from the amplified biological signal as a heart rate signal; an A-D converter 44 for A-D converting a heart rate signal; and a control part 45 for estimating the sleep state based on the heart rate signal after the A-D conversion. In this control part 45, the average value of data, which is the magnitude of a heart rate signal after A-D conversion, is calculated during a predetermined period, and the ratio of the number of deviations from the average value within a predetermined range to the total data number is obtained. When the ratio is larger than a predetermined value, the amplification factor of the amplifier 41 is determined to be proper, and when the ratio is smaller than the predetermined value, the amplification factor of the amplifier 41 is determined to be improper. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention detects and amplifies a biological signal that changes according to a sleep state, and filters the amplified biological signal to extract a signal within a predetermined frequency band as an input signal from the biological signal. The present invention relates to a biological signal processing apparatus that estimates a sleep state based on the input signal.

  As one of the known biological signal processing devices of this type, the differential pressure sensor detects the fluctuation in pressure transmitted from the body of the user sleeping on the air mat filled with air to the inside of the air mat as a biological signal. Some of them are equipped with an automatic gain control unit. This automatic gain control unit automatically adjusts the gain (amplification factor) of the biological signal detected by the fine differential pressure sensor, and outputs it to the subsequent filter (see Patent Document 1). With this filter, for example, a signal within a predetermined frequency band corresponding to a heartbeat is extracted as a heartbeat signal from a biological signal, and the fluctuation pattern of the extracted heartbeat signal estimates a user's sleep state on the air mat. To be used to do.

JP 2000-271103 A (paragraphs 0020 to 0022, FIG. 1, etc.)

  However, according to the conventional automatic gain control unit described above, gain adjustment may not be performed properly. That is, a signal in a frequency band necessary for subsequent processing among detected biological signals corresponds to a heartbeat (or respiration). However, even during the sleep time, the user can turn over or stand in the bathroom, and the signal from the body movement other than the heartbeat can act as a disturbance in the biological signal, and the gain automatically responds to this disturbance. This is because there was a case where it was adjusted.

  An object of this invention is to provide the invention which can solve the said subject.

The biological signal processing apparatus according to claim 1 includes a detecting unit that detects a biological signal that changes in accordance with a sleep state, an amplifying unit that amplifies the detected biological signal, and a predetermined extracted from the amplified biological signal. Estimating means for estimating a sleep state based on an input signal within a frequency band.
The biological signal processing apparatus includes a determination unit. That is, this determination means calculates the average value of the data that is the magnitude of the input signal within a predetermined period, and the number of data whose distance from the calculated average value is within the predetermined range is within the predetermined period. The ratio to the number of all data is obtained. At the same time, the determining means determines that the amplification factor of the amplifying unit is appropriate when the obtained ratio is greater than a predetermined value, and the amplification factor of the amplifying unit is determined when the obtained ratio is smaller than the predetermined value. Judge that it is not appropriate.
According to a second aspect of the present invention, there is provided a biological signal processing apparatus including a detecting unit that detects a biological signal that changes in accordance with a sleep state, an amplifying unit that amplifies the detected biological signal, and a predetermined extracted from the amplified biological signal. Estimating means for estimating a sleep state based on an input signal within a frequency band.
The biological signal processing apparatus includes a determination unit. That is, this determination means obtains the maximum data among the frequency components of the input signal obtained by performing spectrum analysis on the input signal. At the same time, the determining means determines that the amplification factor of the amplifying means is appropriate when the obtained maximum data is larger than a predetermined value, and the amplifying means when the obtained maximum data is smaller than the predetermined value. It is determined that the amplification factor is not appropriate.
The biological signal processing apparatus according to claim 3 is the biological signal processing apparatus according to claim 1 or 2, wherein the predetermined frequency band corresponds to a heartbeat or respiration.
The biological signal processing apparatus according to claim 4 is the biological signal processing apparatus according to any one of claims 1 to 3, further comprising a notification unit. When the determination means determines that the amplification factor of the amplification unit is not appropriate, the notification unit notifies that the amplification factor needs to be changed.
The biological signal processing apparatus according to a fifth aspect is the biological signal processing apparatus according to the fourth aspect, further comprising an input unit and a changing unit. The input means is for the user to instruct the change of the amplification factor when the notification means informs that the amplification factor of the amplification means needs to be changed. Change the gain.
The biological signal processing device according to claim 6 is the biological signal processing device according to claim 5, wherein the amplification means uses the biological signal processing device to calculate the amplification factor changed by the changing means when the biological signal processing device is activated this time. It is used from the next start-up of the processing apparatus.
A biological signal processing apparatus according to a seventh aspect is the biological signal processing apparatus according to any one of the first to third aspects, further comprising automatic changing means. The automatic changing means changes the amplification factor when the determination means repeatedly determines that the amplification factor of the amplification means is not appropriate by a predetermined number of times.
The biological signal processing device according to claim 8 is the biological signal processing device according to any one of claims 1 to 7, wherein the detection means includes an air chamber, an incompressible fluid chamber, a pressure receiving membrane, A mat and pressure fluctuation detecting means are provided.
The air chamber is filled with air, and the incompressible fluid chamber is filled with an incompressible fluid. A pressure receiving membrane is provided to partition the air chamber and the incompressible fluid chamber. The mat is filled with an incompressible fluid, and the mat is connected to the incompressible fluid chamber so that the incompressible fluid can flow into the incompressible fluid chamber. The pressure fluctuation detecting means is generated from the living body on the mat, and is transmitted through the incompressible fluid in the mat, the incompressible fluid in the incompressible fluid chamber, the pressure receiving film, and the air in the air chamber in order. Detect pressure fluctuations.

  According to the present invention, for example, whether or not the amplification factor of the amplification means is appropriate by a biological signal in a frequency band corresponding to other body movements other than a predetermined frequency band corresponding to heartbeat or respiration, etc. An erroneous determination can be prevented.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
The sleep measurement apparatus (an example of a biological signal processing apparatus) according to the first embodiment of the present invention will be described first from the overall configuration. As shown in FIG. 1, the sleep measurement device is used together with the bedding 1, and includes a mat 2, a tube 3, and a sleep measurement device main body 4. A user who is a subject of sleep measurement lies on the bedding 1, and a mat 2 is laid under the bedding 1. One end of the tube 3 is connected to the mat 2, and the other end is connected to a biological signal sensor 5 attached to the sleep measuring device main body 4. The mat 2 and the tube 3 are filled with water (an example of an incompressible fluid). As a result, the vibration caused by the heartbeat (pulse), breathing, and other body movements generated from the body of the user (living body) on the bedding 1 is transmitted through the mat 2 and the tube 3 to the biological signal in the sleep measuring device main body 4. It is transmitted to the sensor 5.

  Here, since it is assumed that the mat 2 is laid under the bedding 1, the user is supposed to lie on the mat 2 indirectly, but the user is assumed to lay the mat 2 on the bedding 1. You may make it lie directly on the mat 2. The mat 2 may be laid on the upper side or the lower side of the pillow or may have a pillow shape.

  As shown in FIG. 2, the biological signal sensor 5 of the sleep measurement device main body 4 includes a connection port 51, a water chamber 52, a pressure receiving film 53, an air chamber 54, and a pressure fluctuation detection unit 55. The tube 3 described above is connected to the connection port 51, and the water chamber 52 and the air chamber 54 are partitioned by a pressure receiving film 53. The water chamber 52 is also filled with water so that water can flow from the mat 2 to the water chamber 52 via the tube 3. The air chamber 54 is filled with air, and a pressure fluctuation detection unit 55 is provided at a position facing the pressure receiving film 53 with the air chamber 54 interposed therebetween. Various pressure sensors using the piezoelectric effect are used for the pressure fluctuation detection unit 55.

  The pressure fluctuation transmitted through the mat 2, the tube 3 and the water in the water chamber 52, the pressure receiving film 53, and the air in the air chamber 54 in this order is detected by the pressure fluctuation detecting unit 55, and the pressure fluctuation is detected. The detection unit 55 outputs a voltage signal corresponding to the change in the air pressure as a biological signal to a variable amplifier 41 (described later) in the sleep measurement device body 4. FIG. 3 shows an example of a biological signal that is the output of the biological signal sensor 5. The biological signal shown here includes a signal based on the heartbeat of the user having a period T of about 0.8 seconds. In the biological signal, breathing and other body movements appear in addition to the heartbeat, and these biological signals change in accordance with the user's sleep state (sleep quality) and the like.

  Further, it is known that the magnitude of the output of this biological signal changes with time as shown in FIG. That is, for example, if the sleep measurement device is based on the initial value of 1 when it is first used, it gradually increases, doubles after 3 months, reaches a peak, then gradually decreases, and after 3 months. It has the characteristic of returning to 1 time and then becoming 0.4 times after 6 months. These are considered to be mainly due to the structure of the biological signal sensor 5.

  As shown in FIG. 5, the sleep measurement device main body 4 includes a variable amplifier 41, a filter 42, an amplifier 43, an A / D converter 44, and a control unit 45 in addition to the biological signal sensor 5. The variable amplifier 41 amplifies the biological signal output from the biological signal sensor 5. The amplification factor G (n) of the variable amplifier 41 is based on the setting number n of the amplification factor G (n) set by the control unit 45 as described in detail later. Here, the setting number n = 0, 1, 2 or 3 is set, and the variable amplifier 41 variably sets the amplification factors G (0) to G (3) shown in the following equation 1 in accordance with the setting number n. It is possible. One of the features of the present invention is that when the output of the biological signal sensor 5 changes with time (FIG. 4), the output gain G (n) needs to be changed. It is possible to prompt the user to change, and to manually correct the amplification factor G (n).

フィルタ４２は、3つのバンドパスフィルタ(ＢＰＦ)等により構成される。それら3つのうちの1つのＢＰＦは、可変増幅器４１から出力された生体信号から、0.5Hz〜2Hzといった周波数帯域の心拍に対応する信号を心拍信号（入力信号）として抽出するようになっている。他の1つのＢＰＦは、可変増幅器４１から出力された生体信号から、0.2Hz〜1Hz程度の周波数帯域の呼吸に対応する信号を呼吸信号として抽出するようになっている。さらにもう1つのＢＰＦは、可変増幅器４１から出力された生体信号から、0.2Hz〜2Hz前後の周波数帯域のその他の身体の動きに対応する信号を体動信号として抽出する。

The filter 42 includes three band pass filters (BPF). One of the three BPFs extracts a signal corresponding to a heartbeat in a frequency band of 0.5 Hz to 2 Hz as a heartbeat signal (input signal) from the biological signal output from the variable amplifier 41. The other BPF extracts a signal corresponding to respiration in a frequency band of about 0.2 Hz to 1 Hz as a respiration signal from the biological signal output from the variable amplifier 41. Further, the other BPF extracts, as a body motion signal, a signal corresponding to other body motion in a frequency band of about 0.2 Hz to 2 Hz from the biological signal output from the variable amplifier 41.

  The amplifier 43 amplifies the heartbeat signal, the respiratory signal, and the body motion signal extracted by the filter 42. A fixed value is used for the amplification factor of the amplifier 43. The A / D converter 44 A / D-converts the heartbeat signal, the respiratory signal, and the body motion signal output from the amplifier 43 for processing in the control unit 45 at the subsequent stage.

  The control unit 45 includes a CPU, a RAM, a ROM, and the like, and by executing a predetermined program, the user's sleep state is determined using the heartbeat signal, the respiratory signal, and the body motion signal after the A / D conversion. Estimated. An example of sleep state estimation is to calculate a heart rate from a heart rate signal, and depending on which value the calculated heart rate is in, the sleep stage (stages 1 to 4 of non-REM sleep and REM) Any of sleep) can be determined. It is also possible to calculate the respiration rate from the respiration signal and count how many apneas of 10 seconds or more have occurred during sleep for 7 hours from the calculated respiration rate. The details of the estimation of the sleep state in the control unit 45 and the structure of the biological signal sensor 5 described above are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2004-136618 and 2004-113329. Please refer to it if necessary.

  In addition, a display unit 46, an input unit 47, and an auxiliary storage unit 48 are connected to the control unit 45. The display unit 46 displays the estimation result of the user's sleep state and the fact that the gain G (n) of the variable amplifier 41 needs to be corrected. The input unit 47 includes an amplification factor increase button for increasing the amplification factor G (n) and an amplification factor decrease button for decreasing the amplification factor G (n). The auxiliary storage unit 48 is a nonvolatile memory such as an EEPROM or a hard disk drive. The auxiliary storage unit 48 stores a program executed by the control unit 45, data used in the program, and the like. The control unit 45 may be provided with a communication interface for communicating from the sleep measurement device to the outside.

  As described above, one of the features of the present invention is that when the gain G (n) of the variable amplifier 41 is not appropriate, the gain G (n) can be manually corrected. Hereinafter, a program executed by the control unit 45 (CPU) for manual correction of the amplification factor G (n) will be described with reference to FIGS. The outline of the amplification factor manual correction process shown in FIG. 6 will be described. The control unit 45 performs heart rate after A / D conversion by the A / D converter 44 in the signal input process of step 2 (hereinafter, step is abbreviated as S). Input the signal. Then, the control unit 45 determines in the signal strength determination process of S3 whether the strength (signal strength, signal level) of the heartbeat signal is an under level, a standard level, or an over level. To do. Further, in S4 to S15, the control unit 45 informs the display unit 46 that correction (change, increase or decrease) of the amplification factor G (n) is necessary according to the intensity determined in S3. indicate. At this time, the user can instruct correction of the amplification factor G (n) using the amplification factor increase button or the amplification factor decrease button of the input unit 47, and the control unit 45 can amplify the variable amplifier 41. The amplification factor G (n) is changed according to an instruction for correcting the rate G (n).

  Specifically, in S <b> 1, the control unit 45 first reads the memory value of the setting number n of the amplification factor G (n) from the auxiliary storage unit 48 and sets the setting number n in the variable amplifier 41. Here, the setting number n is stored as a memory value in the auxiliary storage unit 48. When the setting number n is changed to change the amplification factor G (n), the setting in the auxiliary storage unit 48 is changed along with this change. The memory value of number n is also updated.

  In the signal input process of S2, a predetermined number of heartbeat data (digital value of the heartbeat signal), for example, 2400 heartbeat data for 2 minutes are acquired in a predetermined sampling period. That is, as shown in FIG. 7, first, the control unit 45 acquires the heartbeat signal after conversion by the A / D converter 44 (S201), and the heartbeat data that is a digital value of this heartbeat signal is stored in the auxiliary storage unit. The data is stored in 48 (S202). If 0.05 seconds have elapsed since the acquisition of the immediately preceding heartbeat data (YES in S203), it is determined whether or not the acquired heartbeat data is 2400 (S204). The processes of S201 to S203 are repeated until 2400 heartbeat data are completed (YES in S204).

  In the signal strength determination process of S3, as shown in FIG. 8, the control unit 45 first calculates the average value and the deviation (from the average value) of the 2400 heartbeat data obtained by the signal input process described above. (S301). In S302 to S305, it is determined whether or not the obtained ratio is larger than a predetermined value while obtaining the ratio of the number of heartbeat data whose deviation of the heartbeat data is within a predetermined range to the number of all data. By doing so, it is determined whether or not the intensity of the signal is appropriate.

  Here, it is assumed that the signal strength is any one of (1) no signal level, (2) abnormal level, (3) under level, (4) standard level, and (5) over level. If the signal strength is (4) standard level, the amplification factor G (n) of the variable amplifier 41 is appropriate. If the signal strength is (3) under-level or (5) over-level, the gain G (n) is not appropriate. Also, here, the predetermined range for the deviation of the heart rate data is set to a range based on the resolution of the A / D converter 44 (10 bits, an integer value of 0 to 1023 is output). . That is, in FIG. 9, the upper limit value corresponds to the resolution of the A / D converter 44, and the predetermined range is a range from a lower value to an upper value. The control unit 45 determines the strength of the signal by using the ratio of the number of data within the predetermined range.

  More specifically, in S302, when determining whether or not the signal intensity is (1) no signal level, first, the deviation of the heartbeat data is within a first predetermined range, for example, an A / D converter. The number of heartbeat data within the range of -1% to + 1% of the resolution of 44 (within the range of output values of -10 to +10) is counted. Then, the ratio of the counted number of heartbeat data to the number of all heartbeat data is obtained. If the calculated ratio is equal to or greater than the first predetermined value, for example, 90% or greater, it is determined that there is no signal level (YES in S302), and the result determination flag FL is set to indicate the determination result. The value 0 is substituted (S306). (The result determination flag FL is used for processing after S4 in FIG. 6 to be described later.)

  In S303, when determining whether or not the signal intensity is (2) an abnormal level, first, the heartbeat data deviation is -49% to +2 of the second predetermined range, for example, the resolution of the A / D converter 44. The number of heartbeat data that is outside the range of 49% (outside the range of output values of -501 to +501) is counted. A ratio of the counted number of heartbeat data to the total number of heartbeat data is obtained. If the obtained ratio is equal to or greater than the second predetermined value, for example, 0.2% or greater, it is determined that the level is abnormal (YES in S303), and as shown, value 4 is set in result determination flag FL. Substituted (S307).

  In the determination of whether or not the signal intensity at S304 is (3) an underlevel, the heartbeat data deviation is within a third predetermined range, for example, -5% to + 5% of the resolution of the A / D converter 44. The number of heartbeat data within the range (within the output value range of −51 to +51) is counted, and the ratio of the counted number to the whole is obtained. If the calculated ratio is not less than the third predetermined value, for example, 90% or more, it is determined that the level is too low (YES in S304), and value 1 is substituted into result determination flag FL (S308). .

  Further, in S305, it is determined whether the signal strength is (4) a standard level or (5) an excessive level. That is, the deviation of the heart rate data is in a fourth predetermined range, for example, within a range of −20% to + 20% of the resolution of the A / D converter 44 (within an output value range of −255 to +255). The number of heartbeat data is counted, and the ratio of the counted number is obtained. If the calculated ratio is equal to or greater than the fourth predetermined value, for example, 70% or greater, it is determined that the level is the standard level (YES in S305), and value 2 is substituted into result determination flag FL (S309). If the calculated ratio is less than the fourth predetermined value, it is determined that the level is excessive (NO in S305), and value 3 is substituted into result determination flag FL (S310).

In summary, the determination in S302 to S305 is performed in order to determine the signal strength, and the result determination flag FL is set as follows in S306 to S310.
(1) Data with deviation within ± 1% of resolution is 90% or more of the whole → No signal level (FL = 0)
(2) Data with a deviation of ± 49% or more of resolution is 0.2% or more of the whole → abnormal level (FL = 4)
(3) Data with deviation within ± 5% of resolution is 90% or more of the whole → Under level (FL = 1)
(4) Data with a deviation within ± 20% of the resolution is 70% or more of the whole → Standard level (FL = 2)
(5) Other than (1) to (4) → Excessive level (FL = 3)

  In the processing after S4 in the amplification factor manual correction processing of FIG. 6, display according to the intensity of these signals, reception of input according to this display, change of the amplification factor G (n) of the variable amplifier 41, and the like are performed. Is called. That is, in S4 to S6, it is determined whether the signal intensity is one of the above five types. As a result, if the signal intensity is no signal level or abnormal level (YES in S4), S7 is processed. Is done. If the intensity of the signal is too low (YES in S5), S8 to S11 are processed, and if it is the standard level (YES in S6), S12 is processed. If it is an excessive level (NO in S6), S13 to S15, S11 are processed.

  More specifically, first, when the result determination flag FL is 0 or 4 (YES in S4), in other words, when the signal strength is a no-signal level or an abnormal level, the control unit 45 performs measurement. A display for instructing redo is performed on the display unit 46 (S7), and this process ends.

  When the result determination flag FL is 1 (YES in S5), that is, when the signal strength is an excessively low level, the control unit 45 prompts an increase in the amplification factor G (n), for example, “amplification factor”. Please raise the message "on the display unit 46 (S8). Further, for example, the display unit 46 may be configured using a lamp, and the lighting of the lamp may display that the amplification factor G (n) is increased.

  If the control unit 45 is instructed to increase the gain G (n) by the user pressing the gain increase button of the input unit 47 (YES in S9), the control unit 45 The setting number n is increased within the range of the lower limit value 0 to the upper limit value 3 so as to increase (n) (S10). For example, if the original setting number n is the value 1 and an increase is instructed, the new setting number n becomes the value 2. Even if the original setting number n is the value 3 and an increase is instructed, the setting number n is not increased more than that, and the setting number n is maintained at the upper limit value 3. The setting number n of the amplification factor G (n) is stored in the auxiliary storage unit 48. As the setting number n increases, the memory value in the auxiliary storage unit 48 is updated (S11), and this process ends. To do.

  When result determination flag FL is 2 (YES in S6), that is, when the signal strength is at the standard level, control unit 45 indicates that change of amplification factor G (n) is not required. Is displayed (S12). When the result determination flag FL is 3 (NO in S6), that is, when the signal strength is an excessive level, the control unit 45 prompts a decrease in the amplification factor G (n), for example, “ Please lower the amplification factor "message on the display unit 46 (S13).

  When the user instructs the control unit 45 to decrease the gain G (n) by pressing the gain reduction button of the input unit 47 (YES in S14), the control unit 45 The setting number n is decreased within the range of the lower limit value 0 to the upper limit value 3 so as to decrease G (n) (S15). For example, if the original setting number n has a value 1 and a decrease is instructed, the new setting number n has a value 0. Even if the original setting number n has the value 0 and the reduction is instructed, the setting number n is not decreased smaller than that, and the setting number n remains at the lower limit value 0. As the setting number n decreases, the memory value is updated (S11), and this process ends.

  The amplification factor G (n) with the setting number n changed (updated) when the sleep measurement device is started up in this manner is used in the variable amplifier 41 from the next startup of the sleep measurement device. It has become.

  According to the above sleep measurement device, whether or not the intensity of the signal is appropriate based on the distribution state of the heart rate data (digital value of the heart rate signal) after A / D conversion by the A / D converter 44, that is, variable. It is determined whether or not the amplification factor G (n) of the amplifier 41 is appropriate (S302 to S305 in FIG. 8, FIG. 9, etc.). Therefore, an erroneous determination is made as to whether or not the amplification factor G (n) in the variable amplifier 41 is appropriate based on a biological signal in a frequency band corresponding to other body movements other than the frequency band corresponding to the heartbeat signal. Can be prevented.

(Second Embodiment)
Next, a sleep measuring apparatus according to the second embodiment of the present invention will be described. In the present embodiment, while automatically correcting the amplification factor G (n) of the variable amplifier 41, heartbeat data, respiratory data (respiration signal after A / D conversion), and body motion data (A This is different from the first embodiment in that measurement data consisting of (body motion signal after / D conversion) is acquired. That is, when the sleep measurement device according to the present embodiment acquires measurement data and determines that the amplification factor G (n) of the variable amplifier 41 is not appropriate based on the heartbeat data, the sleep measurement device calculates the amplification factor G (n). It is designed to automatically correct. Except for the configuration and operational effects of the sleep measurement device described here, it is assumed that it conforms to the first embodiment.

  The outline of the measurement data acquisition process shown in FIG. 10 will be described. In S24, the signal input process similar to that of FIG. 7 described above is performed, and in S25, the signal intensity determination process similar to that of FIG. . Then, when it is determined repeatedly by a predetermined number of times (here, 10 times) that the signal strength is the same level by the processing of S28 to S30, etc., the gain G (( n) is increased or decreased according to the level.

  Specifically, when a predetermined measurement start button provided in the input unit 47 is pressed, the control unit 45 executes the main measurement data acquisition process. First, the control unit 45 reads the memory value of the setting number n for the variable amplifier 41 from the auxiliary storage unit 48, and sets the setting number n in the variable amplifier 41 (S21). Subsequently, the control unit 45 assigns a value 1 to the counter CT (S22). Here, the counter CT = 1, 2,..., 10 and the result determination flag is FL (CT). This result determination flag FL (CT) represents the intensity of the signal determined based on 2400 pieces of heartbeat data obtained in 2 minutes, like the result determination flag FL of the first embodiment described above. .

  In S23, it is determined whether or not a predetermined measurement end button provided in the input unit 47 has been pressed. If the measurement end button is not pressed (NO in S23), in S24, the signal input process similar to that in FIG. 7 described above is performed. However, in the first embodiment, since it is assumed that the manual correction itself is performed in a dedicated execution mode, S201 and S202 in FIG. 7 perform processing on the heartbeat signal. In contrast, in the present embodiment, since it is assumed that automatic correction is performed together with normal sleep measurement, the steps corresponding to S201 and S202 are processed for a heartbeat signal, a respiratory signal, and a body motion signal. It is intended to do.

  Subsequently, in S25, a signal strength determination process similar to that in FIG. 8 described above is performed. As described above, here, the determination result regarding the strength of the signal is obtained as the value of the result determination flag FL (CT). As a result, when determination flag FL (CT) is 0, 2, or 4 (YES in S26), that is, when the intensity of the signal in this measurement is a no-signal level, a standard level, or an abnormal level, The process is moved to S22. In S22, the counter CT indicating the number of times that the signal strength is continuously determined to be inappropriate is cleared to the value 1, and the measurement data acquisition is continued.

  If the result determination flag FL (CT) is not the value 0, 2 or 4 in S26 (NO in S26), that is, if the signal strength in the current measurement is an under level or an over level, the counter CT It is determined whether or not the value is 1 (S27). If counter CT is not a value 1 but an integer of 2 to 10 (NO in S27), it is determined in S28 whether result determination flag FL (CT) is equal to result determination flag FL (CT-1). Is done. If the result judgment flag FL (CT) is not equal to the result judgment flag FL (CT-1), that is, the signal strength in this measurement is the same as that of the previous measurement about 2 minutes before the measurement data sampling period. If it is not equal to the signal strength (NO in S28), the process proceeds to S22 as described above. If the signal intensity in the current measurement is equal to the signal intensity in the previous measurement (YES in S28), a value of 1 is added to counter CT (S29), and the value of this counter CT has reached 11 It is determined whether or not (S30).

  That is, if the result determination flag FL (1) is 1 or 3 in S26 and the counter CT is 1 in S27, the determination in S28 is skipped, and the value of the counter CT is 2 in S29. It is said. As a result, the process proceeds to S30 while the result determination flag FL (1) obtained by the signal input process in S24 and the signal intensity determination process in S25 corresponding to the value 1 of the counter CT is held. become.

  If the counter CT is not 11 in S30 (NO in S30), the process proceeds to S23, that is, the signal input process in S24 and the signal strength determination in S25 without the counter CT being cleared. The process is repeated. If counter CT has a value of 11 (YES in S30), that is, if result determination flags FL (1) to FL (10) hold the value at 1 or 3, the amplification factor of S31 Change processing is performed. After the amplification factor changing process, if the counter CT is cleared in S22 and the measurement end button is not pressed (NO in S23), a signal input process in S24, a signal intensity determination process in S25, and the like are performed.

  In the amplification factor changing process of S31, as shown in FIG. 11, first, the setting number n of the variable amplifier 41 is changed within the range of the lower limit value 0 to the upper limit value 3 in accordance with the result determination flag FL (10). (S311). That is, similarly to S10 in the above-described amplification factor manual correction process of FIG. 6, for example, when the original setting number n is 1, the result determination flag FL (10) is 1 and the level is too low. If continuous is indicated, the setting number n is incremented to a value of 2. In addition, when the original setting number n is 3, even if the result determination flag FL (10) has a value 1 indicating continuous underlevel, the setting number n remains at the upper limit value 3. The In addition, as in S15 in the amplification factor manual correction process of FIG. 6, for example, when the original setting number n is a value 2, the result determination flag FL (10) is a value 3 and an excessive level continues. , The setting number n is reduced to the value 2. Further, when the original setting number n is 0, even if the excessive level continues, the setting number n remains at the lower limit value 0.

  The value of the result determination flag FL (10), the change time, and the value of the setting number n before and after the change are stored for later recalculation of measurement data in S32 of FIG. 10 (S312 and S313). Thus, the amplification factor changing process ends. After execution of the amplification factor changing process (S31 in FIG. 10), the process is shifted to S22, the counter CT is cleared in S22, the signal input process in S24, the signal intensity determination process in S25, and the like. Is continued.

  If the measurement end button has been pressed in S23 (YES in S23), control unit 45 recalculates the measurement data in S32. That is, when the gain G (n) of the variable amplifier 41 is changed, for example, even if measurement data of the same two values is acquired on the control unit 45 side before and after the change, these two measurements are performed. Regarding the data, the magnitude of vibrations that actually occur from the user is different. In S312 of the amplification factor changing process of FIG. 11, the result determination flag FL (10) that is a source of changing the amplification factor G (n) is stored, and in S313, the time when the setting number n is changed. Since the value of the setting number n before and after the change is stored, the measurement data before and after the change of the gain G (n) can be matched using these values.

  For example, it is assumed that the setting number n is increased from the value 1 to the value 2 at time 23:55 because the result determination flag FL (10) has the value 1. In this case, since the amplification factor G (2) is three times the amplification factor G (1) in the above equation 1, the measurement data after time 23:55 is consistent with the measurement data before that time. It is multiplied by (1/3) in order to maintain its consistency. Through these processes, the measurement data acquisition process ends.

  According to the sleep measurement device described above, based on the distribution state of the heartbeat data after A / D conversion by the A / D converter 44, whether the signal intensity is appropriate, that is, the amplification factor G (n of the variable amplifier 41) ) Is appropriate. Therefore, an erroneous determination is made as to whether or not the amplification factor G (n) in the variable amplifier 41 is appropriate based on a biological signal in a frequency band corresponding to other body movements other than the frequency band corresponding to the heartbeat signal. Can be prevented. Furthermore, since the amplification factor G (n) is automatically changed based on the determination, it is more convenient for the user than the sleep measurement device of the first embodiment.

(Other embodiments, etc.)
As mentioned above, although this invention was demonstrated by specific embodiment, this invention is not limited to the said embodiment, It can change and implement in the range which does not deviate from the summary of this invention.
(A) In each of the above embodiments, for example, a predetermined range for deviation from the average value (upper and lower values in FIG. 9, resolution of the A / D converter 44) used when determining the signal strength. The range of -20% to + 20%) is a predetermined value. Instead of this, the predetermined range may be determined using a statistic such as a standard deviation or variance.
Further, when determining the intensity of the signal, the deviation represents the separation of data from the average value, and the number of data whose deviation is within a predetermined range was counted. The distance between each data and its average value may be a square of the deviation, or a value obtained from each other data and the average value.

(B) The determination of the intensity of the signal is based on the distribution state of the heartbeat data size (FIG. 9). Instead of this, it may be based on the magnitude of the frequency component of the heartbeat data obtained by spectral analysis of the heartbeat data.
That is, as shown in FIG. 12, the control unit 45 of the sleep measurement apparatus first obtains the maximum one of the data (the spectrum of the heartbeat data or the power spectrum) that is the frequency component of the heartbeat data. Yes. When the obtained maximum data is larger than a predetermined value, that is, a predetermined threshold value or a value that is several times the average value of the data, the control unit 45 determines the amplification factor G (n ) Is determined to be appropriate. When the maximum data is smaller than the predetermined value, the control unit 45 determines that the amplification factor G (n) is not appropriate and the signal strength is too low.
Such determination also makes an appropriate determination as to whether the signal strength is appropriate.

  (C) Although the intensity of the signal is determined using the heartbeat signal, the intensity of the signal may be determined using a biological signal in another frequency band such as a respiratory signal or a body motion signal. In this case, in S201 of the signal input process shown in FIG. 7 of the first embodiment described above, a signal for which the strength of the signal is determined is acquired, and the digital value after the A / D conversion is stored in S202. Will be. If the intensity of any of these signals is individually determined and the intensity of any of the signals is not appropriate, the amplification factor G (n) may be changed based on the intensity of the signal.

  (D) In each of the above embodiments, the A / D converter 44 performs A / D conversion on the heartbeat signal obtained from the biological signal sensor 5 through the variable amplifier 41, the filter 42, and the like. . The order of the variable amplifier 41, the filter 42, the A / D converter 44, etc. may be changed, and for example, the filter 42, the A / D converter 44, etc. may be provided in the previous stage of the variable amplifier 41.

  (E) The biological signal sensor 5 is assumed to be connected to the mat 2 filled with water. Unlike this, the mat 2 may be filled with air. In addition, the biological signal sensor 5 (the main part of the detection means for detecting the biological signal) is not connected to the mat 2 and further does not include part or all of the water chamber 52, the pressure receiving membrane 53, and the air chamber 54. It may be a thing. For example, the biological signal sensor 5 as the biological signal detection means may be constituted by a pressure fluctuation detection means composed of a single piezoelectric element or the like.

  (F) In the first embodiment, the display unit 46 notifies the user that the gain G (n) of the variable amplifier 41 is not appropriate. Alternatively or in addition to this, the sleep measurement device may be provided with a sound output unit for reproducing and outputting sound, and notification to the user by sound output such as "Please increase the amplification factor" Good. In addition, the sleep measurement device is provided with a communication processing unit for processing communication with an externally connected PC or the like, and by transmitting predetermined data to the externally connected PC or the like, Notification may be performed.

  (G) In the second embodiment, for example, when it is necessary to change the gain G (n) two or more times from the determination of the intensity of the signal during one measurement overnight. Alternatively, the control unit 45 may limit the change of the gain G (n) so that the gain G (n) is not changed twice or more during one measurement. Thereby, it is possible to prevent the amplification factor G (n) from being erroneously set from erroneous determination of the signal strength.

  Specifically, when it is first determined that the signal intensity is at an excessively low level during one measurement, the setting number n of the amplification factor G (n) is increased by one. Thereafter, (1) the setting number n (amplification factor G (n)) is not changed even if it is determined that the signal intensity is too low. On the other hand, (2) if it is determined that the signal strength is at an excessive level, the setting number n of the amplification factor G (n) is decreased by 1, thereby returning the amplification factor G (n) to the original setting.

  Further, when it is first determined that the intensity of the signal is an excessive level during one measurement, the setting number n of the amplification factor G (n) is decreased by 1. Thereafter, (1) the setting number n is not changed even if it is determined that the level is excessive again. (2) If it is determined that the level is too low, the setting number n is increased by 1, and the amplification factor G (n) is returned to the original setting.

It is a figure showing the whole sleep measuring device composition of a 1st embodiment concerning the present invention. 2 is a diagram illustrating a configuration of a biological signal sensor 5. FIG. It is a graph which shows the example of a biomedical signal. It is a graph which shows the time-dependent change of the magnitude | size of the output of a biomedical signal. It is a figure which shows the structure of the sleep measurement apparatus main body. It is a flowchart which shows the flow of an amplification degree manual correction program. It is a flowchart which shows the signal input process of S2 of FIG. It is a flowchart which shows the signal strength determination process of S3 of FIG. It is a figure for demonstrating the 1st example of the determination method of signal strength. It is a flowchart which shows the measurement data acquisition process with an automatic correction | amendment in the sleep measurement apparatus of 2nd Embodiment. It is a flowchart which shows the gain change process of S31 of FIG. It is a figure for demonstrating the 2nd example of the determination method of signal strength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Bedding 2 ......... Mat 3 ......... Tube 4 ......... Sleep measuring device main body 5 ......... Biological signal sensor (part except the mat of the detection means)
41 …… Variable amplifier (amplification means)
42... Filter 43... Amplifier 44... A / D converter 45... Controller (estimating means, judging means, changing means together with execution program)
46 …… Display section (notification means)
47 …… Input section (input means)
48 …… Auxiliary storage 51 …… Connection port 52 …… Water chamber (incompressible fluid chamber)
53 …… Pressure receiving membrane 54 …… Air chamber 55 …… Pressure fluctuation detecting section (pressure fluctuation detecting means)

Claims (8)

Detection means for detecting a biological signal that changes according to the sleep state;
Amplifying means for amplifying the detected biological signal;
A biological signal processing apparatus comprising: an estimation unit that estimates a sleep state based on an input signal within a predetermined frequency band extracted from the amplified biological signal,
An average value of the data that is the magnitude of the input signal within a predetermined period is calculated, and the number of data whose distance from the calculated average value is within a predetermined range is calculated for all the data within the predetermined period. A ratio to the number is obtained, and when the obtained ratio is larger than a predetermined value, it is determined that the amplification factor of the amplifying means is appropriate, and when the obtained ratio is smaller than the predetermined value, the amplification is performed. A biological signal processing apparatus comprising: a determination unit that determines that the amplification factor of the unit is not appropriate. Detection means for detecting a biological signal that changes according to the sleep state;
Amplifying means for amplifying the detected biological signal;
A biological signal processing apparatus comprising: an estimation unit that estimates a sleep state based on an input signal within a predetermined frequency band extracted from the amplified biological signal,
The maximum of the data that is the frequency component of the input signal obtained by performing spectrum analysis on the input signal is obtained, and when the obtained maximum data is larger than a predetermined value, the amplification means A biological signal comprising: a determination unit that determines that the amplification factor is appropriate and determines that the amplification factor of the amplification unit is not appropriate when the obtained maximum data is smaller than the predetermined value Processing equipment. The predetermined frequency band is:
The biological signal processing apparatus according to claim 1, wherein the biological signal processing apparatus corresponds to heartbeat or respiration.   The information processing apparatus according to claim 1, further comprising notification means for notifying that the amplification factor needs to be changed when the determination means determines that the amplification factor of the amplification means is not appropriate. 4. The biological signal processing apparatus according to any one of 3 above. When the notification means informs that it is necessary to change the gain of the amplification means, the input means for the user to instruct the change of the gain;
5. The biological signal processing apparatus according to claim 4, further comprising changing means for changing the amplification factor in response to an instruction from the input means. The amplification means includes
6. The biological signal processing apparatus according to claim 5, wherein the amplification factor changed by the changing means when the biological signal processing apparatus is activated this time is used from the next activation of the biological signal processing apparatus.   The automatic change means for changing the amplification factor when the determination unit repeatedly determines that the amplification factor of the amplification unit is not appropriate by a predetermined number of times. 4. The biological signal processing apparatus according to any one of 3 above. The detection means includes
An air chamber filled with air;
An incompressible fluid chamber filled with an incompressible fluid; and
A pressure-receiving membrane that partitions between the air chamber and the incompressible fluid chamber;
A mat filled with an incompressible fluid and connected to the incompressible fluid chamber so that the incompressible fluid can flow into the incompressible fluid chamber;
Pressure generated from the living body on the mat and transmitted through the incompressible fluid in the mat, the incompressible fluid in the incompressible fluid chamber, the pressure receiving film, and the air in the air chamber in this order. The biological signal processing apparatus according to any one of claims 1 to 7, further comprising: a pressure fluctuation detection unit that detects a fluctuation of the blood pressure.

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