JPH0661322B2 - Body fat measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a body fat measuring device for electrically measuring body fat.

[0002]

2. Description of the Related Art In the field of cosmetic treatment and medical treatment, body fat is measured and knowledge of obesity degree provides a guideline for appropriate treatment such as diet therapy, treatment or aerobic exercise. It has been reported by Brozek et al. That the proportion of fat in the human body is related to body density (J. Brozek
et al, Ann NY Acad Sci., 1963, 110; 113-40). In addition, Lukaski et al. Have reported that the weight excluding fat is proportional to the amount obtained by dividing the height squared by the body impedance (HC Lukaski et al, The American Jo
urnal of Clinical Nutrition, 41 (1985) 810-817).
Since this report, various electric devices for measuring the percentage of body fat have been developed. The present applicant has already proposed some body fat measuring devices. These devices are devised to obtain stable and reliable measurement values.

In the report of Lukasky et al., The above-mentioned relationship has been confirmed by measuring body impedances for many men. However, a body fat measuring method suitable for a woman, particularly for the purpose of being used as a guideline for beauty treatment, has not been proposed. Moreover, appropriate values for Japanese have not been determined for the parameters that characterize the above relational expression.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a measuring device capable of obtaining a stable and reliable measurement value of body fat even with a simple structure. . Further, an object of the present invention is to provide a parameter of a relational expression that characterizes the ratio of body impedance and body fat to a Japanese person, particularly a Japanese woman, and realize this measurement. To provide.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the above object is to provide a measuring probe consisting of four electrodes which can be electrically conductively adhered to the skin of a human body, and a constant frequency between two of the electrodes. A body impedance Z is obtained from a voltage generator for applying an AC voltage and a potential between the other two electrodes to obtain a detection voltage of the signal component of the constant frequency, and an output voltage of the detector. In order to obtain and calculate the body fat ratio F from the impedance and the height H and weight W of the person to be measured by digital processing, an arithmetic processing unit including an analog / digital converter, a memory, and a microprocessor, the voltage generating unit, and An intermediate part provided to prevent the electrical connection between the four electrodes from being directly connected to the detection part; and an input / output part for inputting the personal data and displaying the obtained result, A transformer whose interposition is coupled to the voltage generation unit, another transformer coupled to the detection unit, and two dummies for determining the relative relationship between the detected voltage including the voltage generation unit and the detection unit and the actual impedance. Resistors, dummy resistors of these, and an AC voltage of a certain frequency are applied to the electrodes on the skin of the human body, and are connected between the electrodes and both transformers in order to switch and obtain the detection voltage generated by the applied voltage. This is solved by a body fat measuring device that has a changeover switch.

Other advantageous configurations according to the invention are described in the dependent claims.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail with reference to the drawings showing the embodiments. FIG. 1 is a general block diagram showing a circuit configuration of a body fat measuring device according to the present invention. The measurement is based on the so-called 4-terminal method, and the measurement probe P
B is composed of four independent electrodes, and the electric signals of the four electrodes are introduced into the calibration circuit CAB according to the present invention, which will be described in detail later, via the connecting conductor L ₀ . The four electrodes of the measurement probe PB are attached to the skin surface of the human body to be measured at predetermined intervals. An applied voltage, a sinusoidal alternating voltage of 50 kHz in the present invention, is applied to the two electrodes. The detection voltage is detected from the remaining two electrodes attached between these electrodes to obtain the impedance of the body.

The applied voltage is first formed by the oscillator Os.
A sinusoidal AC voltage of 50 kHz is introduced into the drive circuit Dv and further into the primary side of the transformer T1. Then, the output voltage on the secondary side is sent to the measurement probe PB via a changeover switch (not shown in FIG. 1) which will be described later in detail. In the embodiment of the invention, the applied voltage is about 7.5 volts between peak values. The detected voltage detected by the measuring probe PB is likewise supplied to the transformer T2 via a changeover switch (not shown in FIG. 1) and introduces the output signal on its secondary side into the bandpass filter FT. In that case, this filter consists of a narrow band active filter using an operational amplifier,
The tuning frequency is set to 50 kHz in the embodiment of the present invention. The filtered signal is introduced into a subsequent rectifier circuit RT, converted into a detected DC signal, subjected to waveform shaping, level adjustment and offset adjustment by an amplifier Am, and then, as will be described later in detail, a central processing unit. The PRB is digitally converted into a body fat value according to a predetermined arithmetic expression. Then, the obtained data is output to the output display section DS including the display device and the printing device. In addition, the relevant data of the person to be measured, that is, sex, age, height, weight, etc., is input from the input keyboard CB, is stored in a predetermined memory location in the central processing unit PRB, and is used when performing a related calculation. To be done. The operation of the changeover switch in the calibration circuit CAB is performed by sending the control signal formed by the central processing unit PRB to the calibration circuit CAB via the conductor L ₁ . The two transformers T1 and T2 are also used to electrically insulate the applied power source and the power source of the detection processing unit from being directly applied to the human body to be measured. Since the frequency is relatively high, it is advantageous to use a ferrite core for the magnetic cores of the transformers T1 and T2.

FIG. 2 shows a measuring probe PB and a calibration circuit C.
Details of AB are shown. 4 pasted on the body BD
Individual electrodes P_1,P₂AC voltage is applied between the
_1,P ₂Other electrode P pasted in between_3,P_FourMeasure the voltage between
Then, the impedance of the human body is measured. Usually a measurement professional
A pair of curves, that is, electrode P in the case of_1,P₃The back of the hand
Rui on wrist, electrode P_2,P_FourOn the instep or ankle
paste. In that case, the entire measurement detector, that is,
Solid circuit elements Os, Dv, T_1,T_2,FT, RT, Am
Reduces undesired errors due to changes over time, temperature fluctuations, etc.
Therefore, before measuring the impedance of the human body,
Calibrate the output characteristics. For this calibration, the amplifier Am
Output signal V₀Directly to the absolute value of the impedance Z of the human body
Offset component C that is not proportional but constant₀Also has
(That is, Re (Z) = k · V₀+ C₀; Re is the whole
Value), two dummy resistors R_1,R₂Using
Transformer T for each resistance₁Constant AC applied voltage from
Given, measure the voltage across the resistor and keep constant with proportionality coefficient k
Offset value C₀Need to ask. Implementation of this invention
In the example, R₁And R₂Are 220 Ω and 910 Ω, respectively.
It was The above switching is performed by the control conductor L₁Central processing unit via
Based on the control signal from the switch SW as shown₁~
SW_FourControl unit RE₁And switch SW_FiveControl unit RE
₂Done with the help of. Then, the parameters k and C₀
And calculation of the actual value of the impedance Z of the human body
Is the central processing unit PR each time the output signal of the amplifier Am is switched.
Send to B, help of memory and microprocessor in this
Done by

In this switching process, as shown in the flow chart of FIG. 3, when the start of measurement is instructed, the switching switches SW _{1 to} SW ₅ are switched so as to measure the dummy resistance R ₁ in step S1. Then, it measures for a predetermined time, for example, 1.5 seconds, and sends the detection output signal during that time to the central processing unit. Then, in step S2, the measurement is switched to the dummy resistance R ₂ according to a command from the central processing unit,
The measurement is performed for a predetermined time, for example, 1.5 seconds, and the detection output signal during that time is sent to the central processing unit. In this way, the parameters k and C ₀ are calculated in the central processing unit. When this preparation is completed, the mode is switched to the mode for measuring the human body impedance again by a command from the central processing unit. This measurement is also performed for 1.5 seconds, for example, and the result is transmitted to the central processing unit,
The body fat content is finally calculated using the parameters k and C ₀ . The result is output by suitable means and the measurement process is completed.

The advantage of using the calibration circuit CAB according to the present invention is that the oscillator Os, the narrow band filter FT, the detection circuit RT, and the amplifier Am use extremely stable and reproducible elements or circuit configurations of these elements. Without this, it is possible to measure with sufficient accuracy, and it is sufficient that the adjustment of various circuits during the manufacturing process and maintenance is relatively easy.
In particular, it is worth noting that there is no need to worry about block compatibility.

Next, FIG. 4 shows an electrical connection relationship between the central processing unit PRB and the input / output unit attached to this processing unit. The central processing unit PRB includes a RAM storage device 12 and a ROM storage device 1.
4 and microprocessor 16 have their own built-in devices. The RAM memory 12 is used for storing and transmitting intermediate numerical values during arithmetic processing. The ROM memory 14 stores a program for a control sequence, a program for a mathematical formula to be described later, or coefficients for those formulas, and numerical values in a table used for calculation. The microprocessor 16 sequentially controls all calculations and controls. In addition, an A / D converter 10 including an interface for converting an analog output signal from the amplifier Am of the detection unit into a digital signal
And a switching control unit 18 including an interface for transmitting the control signal of the switch of the calibration circuit CAB. Further, the central processing unit PRB is further connected to various input / output devices, so that an interface for audio circuit control signal 20, a matrix display decoder 22, an upper / lower limit display decoder 24, an output value display decoder 26, an input value display decoder 28,
An input encoder 30 and an interface 32 for the printer device are included. These circuit elements are connected by a bus connection Bs for transmitting digital signals to each other.

The input / output unit connected to the outside of the central processing unit PRB is provided with a speaker SP connected via a sound generator 34, a dot matrix display unit MX, and a display unit adjacent to the matrix display unit MX. Display windows DW ₁ and DW ₂ that display the upper and lower limits of the ideal body weight and a display window DF that displays the upper and lower limits of the ratio of ideal body fat
₁ and DF ₂ , measurement value display window D that displays the numerical value of the measurement result
P1, individuals age, height, input value display window for displaying a numerical value entered with respect to body weight _{ID 1, ID 2, ID 3} , the input keyboard CB, and, if necessary, printing apparatus PRT which is equipped, usually Comes with a printer. As shown in the figure, these devices include corresponding circuit units 20, 22, 24, 26, 2 including interfaces in the central processing unit PRB.
It is connected to 8, 30, and 32, respectively. The voice generation circuit 34 has a built-in ROM that stores words to be transmitted by the speaker SP in a short message according to the measurement result.
An appropriate message is output according to the control signal supplied from the interface 20 of the central processing unit PRB. In the present invention, the dot matrix display unit MX has 16 lines.
The LEDs are arranged in a matrix of 16 rows, and can emit red, green, or orange depending on the control voltage.
Other display windows DW ₁ , DW ₂ , DF ₁ , DF ₂ , DP _1, ID _1, I
Each of D _{2 and} ID ₃ is composed of a 7-segment LED element having a required number of digits.

FIG. 5 shows a front panel of the body fat measuring device according to the present invention. This arrangement is for power switch 5
Except for 0, it is roughly divided into four parts.
That is, it is an input keyboard unit, an input value display unit, a measured value display unit, and a measured value evaluation display unit as written in the upper part of the drawing.

The input keyboard portion is composed of 16 dot keys, and as shown in the figure, 10 numeric keys 0, 1 to 9, a print start key 60, a measurement start key 62, and a sex input key 5
2. It has an age input key 54, a height input key 56 and a weight input key 58. The sex input key 52 is alternately switched between male and female each time this key is pressed. To enter the age, height, and weight of the person to be measured, press the desired numeric keys 0, 1 to 9 according to the numeric values to be entered, and then enter the corresponding input keys, that is, 54, 56, 58. Complete by pressing either.

The entered age, height and weight values are
The light emitting element SSD, which is a red or blue LED, is displayed each time the gender input key 52 is pressed, which is displayed in the display windows ID _1, ID _{2 and} ID ₃ for the age, height and weight in the input value display section. It lights up, and the corresponding input values, that is, male or female, can be confirmed, and these input values are input to the central processing unit PRB and stored, or undergo a predetermined arithmetic processing.

The measurement display section displays various characteristic values obtained from the above-mentioned personal data input values and the measured human body impedance values. In the illustrated embodiment, the ratio (%) of body fat, the human body Impedance (ohm), average body fat comparison (%), average body weight comparison (kg) and basal metabolism
(kcal) is displayed, and the display can be switched by switching the display each time the display switch key switch _Sa is pressed to display a numerical value corresponding to the display window DP1. It should be noted that, in order to indicate which display is performed by this switching, the light emitting diode L ₁ lit up at the time of the corresponding display
~ L ₅ are provided.

The measured value evaluation display section includes a dot matrix display section MX and an upper limit ideal weight display window DW ₁ capable of displaying the upper limit value and the lower limit value of the ideal weight discriminated from the input individual height. The lower limit ideal body weight display window DW ₂ and the lower limit ideal body fat display window D capable of displaying the lower limit value and the upper limit value of the ratio of ideal body fat under the dot matrix display section MX.
F ₁ and an upper limit ideal body fat display window DF ₂ are provided. The dot matrix display unit MX can display the measurement result by two kinds of display methods, and can be switched alternately by pressing the display changeover key switch S _b .

Although not shown, what is attached to this device is a measurement probe PB having four terminal electrodes which is connected to a connection terminal or a connector receiver provided on the back surface of the device of the front panel of FIG. 5, if necessary. For example, you can connect an optional printer, that is, an optional printer.

In the body fat measuring device according to the present invention, the ratio (F;%) of body fat is calculated from the measured human body impedance (Z; ohm) by software using the stored numerical value and mathematical formula.

As described above, with reference to the evaluation method of Lucaski et al. And the relational expression of Brozek et al., The relational expression suitable for the Japanese with respect to the measured body impedance and the ratio of body fat was obtained by experiment.

[0022] In the case of the male, F = [4.95 / (1.155 -0.084 · W · Z / H 2) - 4.5] • For 100 women, F = [1.00- (0.6483 · H 2 /Z+0.1699 · W + 5.091 ) / W] · 100 was used. The coefficient used in both equations above is 1
Except for 00, all should be set within ± 10%.

[0023]

As described above, by using the body fat measuring device according to the present invention, stable and reliable measurement values can be obtained even if the structure is simple. Further, by using the body fat measuring device according to the present invention, the parameters of the relational expression that characterizes the ratio of body impedance and body fat are given to a Japanese person, particularly a Japanese woman, and this measurement is realized, especially for cosmetic diagnosis. Give appropriate guidance.

[Brief description of drawings]

1 is a general block diagram of an apparatus according to the present invention.

FIG. 2 is a circuit diagram showing a connection between a calibration circuit and a measurement probe.

FIG. 3 is a flowchart showing a calibration and measurement process.

FIG. 4 is a block diagram of an internal configuration of a central processing unit and an attached input / output device.

FIG. 5 is a layout view of the front panel of the device according to the invention.

[Explanation of symbols]

PB measurement probe L ₀ detection lead wire CAB calibration circuit PRB central processing unit CB input keyboard DS output display unit Os oscillator Dv drive unit T1, T2 transformer FT narrow band filter RT detection circuit Am amplifier SW _{1 to} SW ₅ changeover switch R _1, R ₂ Dummy resistance P _{1 to} P ₄ Measuring electrode MX Dot matrix display SP speaker PRT printer DW _1, DW ₂ Display window for upper and lower limits of ideal body weight DF _1, DF _{2 For} upper and lower limits of ideal body fat display window ID _1, ID _2, ID ₃ input value display window DP1 measured value display windows 10 A / D converter 12 RAM memory unit 14 ROM memory 16 microprocessor

Claims (2)

[Claims] 1. A measurement probe comprising four electrodes capable of being electrically conductively adhered to human skin, a voltage generator for applying an alternating voltage of a constant frequency between two of the electrodes, and another The potential between the two electrodes is taken out, the body impedance Z is obtained from the detection unit for obtaining the detection voltage of the signal component of the constant frequency, and the output voltage of the detection unit, and this impedance and the height H and weight W of the person to be measured. Since the ratio F of body fat is calculated by digital processing, the calculation processing section including an analog / digital converter, a storage device, and a microprocessor, and the voltage generation section and the detection section have four values.
An intermediate portion provided to prevent direct electrical connection between the individual electrodes and an inlet / outlet portion for inputting the personal data and displaying the obtained result are connected to the voltage generating portion. A transformer, another transformer coupled to the detection unit, two dummy resistors for defining the relative relationship between the detected voltage and the actual impedance including the voltage generation unit and the detection unit, these dummy resistors and the human body In order to apply the alternating voltage of the constant frequency to the electrode to the skin and switch the detection voltage generated by the applied voltage to obtain it,
A body fat measuring device having a changeover switch connected between an electrode and both transformers. 2. The calculation formula for calculating the body fat ratio F from the measured body impedance Z, height H, and weight W is F = [4.95 / (1.155 −0.084 · W · Z / H ² ). -4.5] · 100 For women, use F = [1.00- (0.6483 · H ² / Z + 0.1699 · W + 5.091) / W] · 100, all coefficients used in both equations except 100 The body fat measuring device according to claim 1, wherein the body impedance Z is ohms, the height H is cm, and the weight W is kg.