JP2003033352A - Signal processing method for ultrasonic biometric device - Google Patents

Abstract

(57) [Problem] To provide a phase tracking method used for ultrasonic biometric measurement with higher accuracy and higher reliability. SOLUTION: In ultrasonic biometric measurement, in order to measure minute vibration of a blood vessel or a heart wall, a constrained least square method is introduced, and an instantaneous position is determined using both the amplitude and the phase of a detection output signal. When tracking by doing,
Evaluating the phase variation and removing the portion where the interference of the received signal occurs removes erroneous tracking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic living body measuring apparatus (ultrasound diagnostic apparatus) for measuring a living body, including a heart,
The present invention relates to a signal processing method for non-invasive measurement of a motion velocity waveform of each part in an artery or other organs.

[0002]

2. Description of the Related Art In the non-invasive diagnosis of the heart (so-called ultrasonic diagnosis) based on the acoustic and elastic characteristics of the myocardium, minute vibrations on the heart wall, which are largely moving due to pulsation, can be highly accurately measured. As a conventional technique for measuring, there is, for example, the technique disclosed in Japanese Patent Laid-Open No. 10-5226. FIG. 9 is a diagram for explaining the principle configuration of the conventional ultrasonic diagnostic apparatus. In FIG. 9, 1 is an ultrasonic transducer, 2 is the surface of the chest of the human body, 3 is the wall of the heart in the body,
4 is an amplifier for amplifying the signal from the ultrasonic transducer, 5 is a quadrature demodulator for converting and demodulating the received signal in a rectangular coordinate system, and 6 is A / for converting an analog signal into a digital signal.
A D converter, 7 indicates a data analysis processing unit.

The ultrasonic transducer 1 is driven by an ultrasonic pulse having a period of ΔT and emits ultrasonic waves from the chest surface 2 toward the inside of the body. The emitted ultrasonic wave has a velocity v
The reflected wave is reflected by the heart wall 3 vibrating at (t), and the reflected wave is received by the ultrasonic transducer 1. The ultrasonic signal of the received reflected wave is amplified by the amplifier 4, detected by the quadrature demodulator 5, and the detected output signal is converted into digital data by the A / D converter 6 at the sampling cycle Ts, and then data analysis is performed. It is input to the processing unit 7.

In the data analysis processing unit 7, the detection signal y (x; t) of the reflected wave from the object at time t and the detection signal y (x; t + ΔT) of the reflected wave for the pulse transmission wave after ΔT seconds. , The phase shift between them is detected, and the distance that the object has moved in ΔT seconds is calculated. At that time, in order to make it stronger against noise, the two waveforms at time t and time t + ΔT do not change in amplitude, but only the phase and the reflected wave position change. Least square matching is performed to detect the phase shift between them, and the vibration velocity v (t) is obtained.

Here, α (Δθ (δx); δx) is the detected waveform y (x; t), assuming that the target moves by δx after ΔT seconds with respect to the detected waveform y (x; t). And y (x + δx; t + ΔT)
2 shows the matching error when the waveforms are matched when the amplitude does not change and only the phase changes by Δθ (Δx).

XεR means that a sum is calculated with respect to x in the range of the region R. This matching error α (Δθ (δx);
It means that δx which minimizes δx) has moved in ΔT seconds. Then, in order to calculate the movement amount after the next ΔT seconds, the same calculation is performed at the position where the region R is shifted by δx to calculate the movement amount. Obtaining δx while sequentially moving the region R in this way is called a phase tracking method.

[0007]

In utilizing the phase tracking method, the ultrasonic wave reflected signal 10 from the front surface of the heart wall 3 and the ultrasonic wave reflected signal 11 from the back surface may overlap each other. If the region R includes this overlapping x, there is no problem if the front surface and the back surface of the heart wall 3 have exactly the same movement, but since the heart wall 3 is usually stretched,
The movements of the front and back surfaces of the heart wall 3 are often different. When the movements of the front surface and the back surface of the heart wall 3 are different as described above, there is a possibility that wrong phase tracking will be performed during ultrasonic diagnosis.

Furthermore, since calculation is performed based on quadrature demodulation,
The received wave should be in a narrow band as much as possible. Therefore, as shown in FIG. 10, in many cases, a narrow band bandpass filter 9 centering on the transmission frequency is arranged in front of the amplifier 4 to narrow the band. However, if the received wave has a narrow band, the length of the temporal waveform becomes long. Then, when the ultrasonic reflection signal 10 from the surface of the heart wall 3 and the ultrasonic reflection signal 11 from the back surface are close to each other, the ultrasonic reflection signal 10 from the front surface and the ultrasonic reflection signal from the back surface are narrowed by narrowing the band. 11 and 11 may overlap.

Further, in FIG. 11, after the δx is obtained in the region R8, it is necessary to perform the region R8 at a position shifted by δx when comparing with the waveform after the next ΔT seconds. However, if the sampling cycle Ts of the A / D converter 6 is rough, data does not always exist at the moved position, so that data close to that position is adopted. In such a case, the center point of the region R is displaced, and it cannot be said that the phase tracking is performed accurately.

Further, in FIG. 12, the repetition period of the received signal is calculated with reference to a certain clock. However, if there is jitter 12 in the part that calculates the start time of the received signal from the clock, y (x; t-ΔT)
And y (x; t) cannot be compared exactly. This is because, for example, y (x; t) is measured more than y (x; t-ΔT) when a reflected wave from a stationary object is analyzed.
This is because, when the time t) is measured, if the reception timing differs by the amount of jitter, that amount is calculated as the movement amount.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to further provide a method for highly accurately tracking the position of an object that fluctuates due to pulsation in ultrasonic diagnosis for measuring a living body. It is an object of the present invention to provide an improved signal processing method for an ultrasonic biometric device.

[0012]

In order to achieve the above-mentioned object, the present invention provides a signal processing method for an ultrasonic biometric apparatus by evaluating the degree of overlap between received signals from the phase variation to determine the phase variation. By automatically prohibiting large areas from being used for analysis, erroneous phase tracking is prevented. Further, it is possible to realize measurement with higher accuracy and reproducibility by performing signal cutting processing in order to prevent overlapping of received signals by the narrow band filter. Further, the region R is also moved without being influenced by the sampling cycle Ts of the A / D converter 6, so that more accurate and reproducible measurement can be realized.

Further, by obtaining the clock at the time of transmission and the clock at the time of reception, obtaining the amount of phase deviation due to the respective jitters, and using the value to correct the amount of phase deviation of the ultrasonic reception signal, the jitter It is also the gist of the present invention to cancel the influence of the above and realize an accurate phase tracking method.

Therefore, the present invention is to further improve the method for tracking the position of an object that fluctuates due to pulsation with high accuracy.

According to the present invention, ultrasonic waves are radiated toward an object inside the body, an ultrasonic signal reflected from the object is detected, and the amplitude and phase of the detected signal are used to instantaneously measure the object. In the analysis means for determining a proper position and precisely tracking the displacement motion of the object, the variation of the phase of the detection signal on the time axis is examined by, for example, the standard deviation, and a threshold value is set for the variation degree. This is a signal processing method for an ultrasonic biometric measuring device that prevents erroneous phase tracking by not using data outside the threshold value range for phase tracking, and performs the phase tracking method with high accuracy. Have an effect.

The present invention also radiates ultrasonic waves toward an object inside the body, detects an ultrasonic wave signal reflected from the object, and uses the amplitude and phase of the detected signal to instantaneously detect the object. In the analysis means for determining the desired position and precisely tracking the displacement motion of the object, the variation of the phase of the detection signal on the time axis is examined by, for example, the standard deviation, and the optimum value is used as the tracking start point. By doing
This is a signal processing method for an ultrasonic living body measuring apparatus that realizes more accurate phase tracking, and has an effect of performing the phase tracking method with high accuracy.

The present invention also radiates an ultrasonic wave toward an object inside the body, detects an ultrasonic signal reflected from the object, and uses the amplitude and phase of the detected signal to instantaneously detect the object. In the analysis means for determining the target position and precisely tracking the displacement motion of the target object, the signals from the respective reflection positions are cut out before detection, and by processing each signal, the adjacent reception signals after detection are It is a signal processing method for an ultrasonic biometric measuring device that prevents the tracking accuracy from being lowered due to overlapping, and has an effect of performing the phase tracking method with high accuracy.

The present invention also radiates an ultrasonic wave toward an object inside the body, detects an ultrasonic signal reflected from the object, and uses the amplitude and phase of the detected signal to instantaneously detect the object. In the analysis means for determining the target position and precisely tracking the displacement motion of the target object, the signal from each reflection position is cut out before the low-pass filtering in the detection processing, and the signal is processed to detect each signal. This is a signal processing method for an ultrasonic biometric measuring device which prevents the reception accuracy of tracking from being deteriorated due to overlapping of received signals that are next to each other, and has an effect of performing the phase tracking method with high accuracy.

The present invention also radiates ultrasonic waves toward an object inside the body, detects an ultrasonic signal reflected from the object, and uses the amplitude and phase of the detected signal to instantaneously detect the object. In the analysis means for determining the desired position and precisely tracking the displacement movement of the object, by using the detection signal upsampled to the time resolution corresponding to the required displacement resolution for the sampling period of the detection signal for analysis, This is a signal processing method for an ultrasonic biometric device that enables accurate analysis at the point slightly displaced from the first point when analyzing the next data, and performs the phase tracking method with high accuracy. Have an effect.

The present invention also radiates an ultrasonic wave toward an object inside the body, detects an ultrasonic signal reflected from the object, and uses the amplitude and phase of the detected signal to instantaneously detect the object. Of the trigger signal for starting the reception from the phase of the clock signal obtained by the clock of the ultrasonic measurement device at the same time as the reception signal in the analysis means for determining the desired position and precisely tracking the displacement movement of the object. It is a signal processing method for an ultrasonic biometric measuring apparatus capable of eliminating time inaccuracies depending on equipment by obtaining time accuracy, and has an effect of performing a phase tracking method with high accuracy.

The present invention also radiates ultrasonic waves toward an object inside the body, detects an ultrasonic signal reflected from the object, and uses the amplitude and phase of the detected signal to instantaneously detect the object. The position of the target and the tracking means for precisely tracking the displacement movement of the object, the signal obtained by adding the clock of the ultrasonic measuring device and the received signal is obtained, and the signal is used as the clock frequency and the received signal frequency, respectively. By obtaining the amplitude and phase of the waveform detected as the carrier signal, and obtaining the time accuracy of the trigger signal for starting reception from the phase of the acquired clock signal, it is possible to eliminate the time inaccuracy that depends on the device. It is a signal processing method for an ultrasonic biometric device, and has an effect of performing a phase tracking method with high accuracy.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. 1 to 7. (Embodiment 1) FIG. 1 shows an experimental configuration for realizing a signal processing method of an ultrasonic living body measuring apparatus of the present invention. As a simulated experiment for measuring the heart wall, candy rubber in water (thickness: about 1 mm) 1
While expanding and contracting 4 at about 1 Hz, the ultrasonic transducer 1 receives each reflected wave from the front and back surfaces of the candy rubber 14. The ultrasonic transducer 1 has a center frequency of 7.5 MHz and a focal length of 15 mm. The transmitted waves were four rectangular waves with a 5.2 MHz period. Experiments were performed at a repetition rate of 500 Hz (ΔT = 0.002 seconds).

FIG. 2 is a block diagram showing the configuration of a signal processing circuit for acquiring data during the experiment in the present embodiment. The signal processing circuit includes an amplifier 4 for amplifying the input ultrasonic wave reception signal, an A / D converter 6 for converting the ultrasonic wave reception signal amplified by the amplifier 4 from an analog signal to a digital signal, and an A / D converter A narrowband bandpass filter 9 that narrows the received signal that is A / D converted by the D converter 6 (sampling frequency 100 MHz), and an orthogonal demodulation processing unit that converts and demodulates the narrowed received signal in an orthogonal coordinate system. 5, a data analysis processing unit 7 that analyzes the demodulated received signal, and a phase evaluation processing unit 16 that evaluates phase variations.

FIGS. 3 (a) to 3 (g) are views showing data acquired at a certain time during the above experiment. Figure 3
(A) shows A / after the ultrasonic reception signal is amplified by the amplifier 4.
It is a figure which shows the RF signal acquired by the D converter 6 (sampling frequency 100 MHz). It can be seen that the reflected wave from the front surface and the reflected wave from the back surface are close to each other near 280 on the x-axis. Note that one point on the x-axis has a sampling frequency of 100.
Equivalent to MHz.

FIG. 3B is a diagram showing a result of applying the narrow band bandpass filter 9 to the signal of FIG. 3A. 3C is a diagram showing the quadrature component (= Q signal) when the quadrature demodulation processing is performed based on the signal of FIG. 3B. Further, FIG. 3D is a diagram showing an in-phase component (I signal) when quadrature demodulation processing is performed based on the signal of FIG. 3B. FIG. 3E is a diagram showing a result of obtaining the phase from the I signal and the Q signal. FIG. 3F is a diagram showing the standard deviation of this phase. The standard deviation was calculated at ± 5 points around each point. Further, the obtained amplitude is shown in FIG.
In the processing of FIGS. 3 (e) to 3 (g), a threshold value is provided for the signal level, and signals below the threshold value are not processed.

As shown in FIG. 3E, the phase is 380 on the x-axis.
It can be seen that there is a change near the point. The phase gradually drops from around 220 points, rises gently from around 350 points, and drops again from around 400 points. During that time, they are connected smoothly. Looking at the standard deviation in FIG. 3 (f), there is a large variation between 300 points and 400 points on the x-axis. This is exactly where the reflected wave on the front surface and the reflected wave on the back surface overlap, and if the phase tracking point uses the data in this, erroneous tracking will occur. Therefore, erroneous phase tracking can be prevented by constantly monitoring the phase tracking point so that it does not use the data therein.

(Second Embodiment) FIG. 4 is a block diagram showing the configuration of a signal processing circuit for acquiring data during the experiment shown in FIG. 1 in the second embodiment of the present invention. . This signal processing circuit includes an amplifier 4 for amplifying the received ultrasonic wave reception signal, and an A / D converter 6 (sampling frequency 100 MHz for converting the ultrasonic wave reception signal amplified by the amplifier 4 from an analog signal to a digital signal). )
And a signal cut-out processing unit 15 which cuts out the A / D-converted received signal in the A / D converter 6 if a predetermined range on the x-axis is designated, and otherwise stores the signal as it is, A narrowband bandpass filter 9 that narrows the received signal cut out by the unit 15, an orthogonal demodulation processing unit 5 that converts and demodulates the narrowed received signal in an orthogonal coordinate system, and analyzes the demodulated received signal. The data analysis processing unit 7 and the phase evaluation processing unit 16 that evaluates variations in phase and determines the range to be cut out in the signal cutout processing unit 15.

In this embodiment, FIG. 5 shows the result of changing the signal processing after conducting the same experiment as in the first embodiment. FIG. 5A shows an A / D converter (sampling frequency 100M after the ultrasonic reception signal is amplified by the amplifier).
It is a figure which shows the RF signal acquired by (Hz). It can be seen that the reflected wave from the front surface and the reflected wave from the back surface are close to each other near 280 on the x-axis. This position can be automatically obtained by evaluating the phase variation. In addition,
One point on the x-axis corresponds to a sampling frequency of 100 MHz.

FIG. 5B shows the signal of FIG. 5A on the x-axis.
It is a figure which shows the result of having applied the narrow band bandpass filter to the signal which cut out the front from 80 points. Further, FIG. 5C is a diagram showing a quadrature component (= Q signal) when quadrature demodulation processing is performed based on the signal of FIG. 5B. Also, FIG.
5D is a diagram showing an in-phase component (I signal) when quadrature demodulation processing is performed based on the signal of FIG. 5B. Figure 5
(E) is a figure which shows the result of having calculated | required the phase from said I signal and Q signal. FIG. 5F is a diagram showing the standard deviation of this phase. The standard deviation was calculated at ± 5 points around each point. Further, FIG. 5 (g) shows the obtained amplitude.

Comparing FIG. 5 (f) with FIG. 3 (f) shows that the range usable as the region R is larger in FIG. 5 (f). Therefore, the matching error obtained by the equation (1) can be obtained accurately. Similarly, the reflected wave from the back surface is cut out as shown in FIG.

FIG. 6 (a) shows the same signal as in FIG. 3 (a). After the ultrasonic wave reception signal is amplified by the amplifier 4, A
The RF signal acquired by the D / D converter 6 (sampling frequency 100 MHz) is the result of applying the narrow-band bandpass filter to the signal cut out from the 280 points on the x-axis.
(B). Further, FIG. 6C is a diagram showing a quadrature component (= Q signal) when quadrature demodulation processing is performed based on the signal of FIG. 6B. In addition, FIG. 6D shows an in-phase component (I) when quadrature demodulation processing is performed based on the signal of FIG. 6B.
It is a figure showing (signal). FIG. 6 (e) is a diagram showing a result of obtaining the phase from the I signal and the Q signal. FIG. 6F is a diagram showing the standard deviation of this phase. The standard deviation was calculated at ± 5 points around each point. Further, FIG. 6 (g) shows the obtained amplitude.

Comparing FIG. 6 (f) and FIG. 3 (f) shows that the range usable as the region R is larger in FIG. 6 (f). Therefore, the matching error obtained by the equation (1) can be obtained accurately.

(Embodiment 3) In the same experiment as in Embodiment 1, FIG. 7 () shows that the signal is overwritten every time the signal of the clock which is the timing of the reception is received at the same time as the reception. a). Then, FIG. 8 is an explanatory diagram of a process for performing the jitter correction in consideration of the fact that the jitter 12 is included in the portion for calculating the start time of the received signal from the clock upon reception. As shown in FIG. 8, the clock at the time of transmission and the clock at the time of reception are acquired, the phase deviation amount due to each jitter 12 is obtained, and the value is used to perform the jitter correction processing on the phase deviation amount of the ultrasonic reception signal. The correction by the unit 13 cancels the influence of the jitter 12 and realizes an accurate phase tracking method. Figure 7 (b)
FIG. 6 is a diagram showing a result of obtaining and correcting the phase deviation of the signal in this way. According to FIG. 7B, it can be seen that the jitter component of the clock signal is considerably reduced.

[0034]

As described above, according to the present invention, the degree of overlap between received signals is evaluated based on the phase variation, so that a portion having a large phase variation is automatically prohibited from being used for analysis. The method of highly accurately tracking the position of the object that fluctuates due to the pulsation has the advantageous effect of being more highly accurate.

Further, according to the present invention, a method of tracking the position of an object that fluctuates due to pulsation with high accuracy by performing signal cutting processing in order to prevent overlapping of received signals by a narrow band filter is more preferable. This has an advantageous effect of achieving high accuracy.

Further, according to the present invention, the region R is moved without being influenced by the sampling period Ts of the A / D converter 6 to accurately track the position of the object which changes due to the pulsation. Has an advantageous effect of higher accuracy.

Further, according to the present invention, the clock at the time of transmission and the clock at the time of reception are acquired, the phase deviation amount due to the respective jitters is obtained, and the value is used to determine the phase deviation amount of the ultrasonic reception signal. By correcting, by canceling the influence of jitter, there is an advantageous effect that the method of tracking the position of the object that fluctuates due to the beat with high accuracy becomes more accurate.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an experimental configuration for realizing a signal processing method of an ultrasonic living body measuring apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a signal processing circuit in the embodiment.

FIG. 3 is a diagram showing data acquired at a certain time during the experiment as an analysis result in the embodiment.

FIG. 4 is a block diagram showing a configuration of a signal processing circuit according to a second embodiment of the present invention.

FIG. 5 is a diagram showing data acquired at a certain time during the experiment as a result of performing an analysis by changing signal processing after performing an experiment in the second embodiment.

FIG. 6 shows a modification of the first embodiment of the present invention.
A figure showing data obtained at a certain time during the experiment as a result of applying a narrow band band-pass filter to a signal obtained by cutting out an RF signal from 280 points on the x-axis.

FIG. 7 is a diagram for correcting a clock signal by obtaining a phase deviation of the clock signal in the third embodiment of the present invention.

FIG. 8 is an explanatory diagram of jitter correction processing according to the third embodiment of the present invention.

FIG. 9 is a diagram explaining the principle of a phase tracking method in conventional ultrasonic diagnosis.

FIG. 10 is an explanatory diagram in which the influence of the back surface reflected wave is included in the region R when the front surface reflected wave is phase-tracked in the conventional ultrasonic diagnosis.

FIG. 11 is an explanatory diagram of movement of an ideal region R in ultrasonic diagnosis.

FIG. 12 is a diagram illustrating a case where jitter is present in a portion for calculating a start time of a received signal from a clock in ultrasonic diagnosis.

[Explanation of symbols]

1 Ultrasonic transducer 2 chest surface 3 heart wall 4 amplifier 5 Quadrature demodulator 6 A / D converter 7 Data analysis processing unit 8 area R 9 Narrow band bandpass filter 10 Ultrasonic reflection signal from the surface 11 Ultrasonic reflection signal from the back side 12 Jitter 13 Jitter correction processing 14 Underwater candy rubber (thickness about 1 mm) 15 Progressive cutting processing unit 16 Phase evaluation processing unit

Continued front page    F term (reference) 4C301 AA01 DD06 DD07 EE11 EE20                       HH51 HH54 JB03 JB06 JB17                       JB22 JB23 JB38 JB50 LL04                 5J083 AA02 AB17 AC28 AD01 AE10                       BA01 BE14 BE39 BE54

Claims (7)

[Claims] 1. An ultrasonic wave is radiated toward an object inside the body,
In an analysis means for detecting an ultrasonic signal reflected from the object, determining the instantaneous position of the object using the amplitude and phase of the detected signal, and precisely tracking the displacement movement of the object. , Statistically examining the variation of the phase of the detection signal on the time axis, setting a threshold value to the degree of the variation, and preventing data outside the range of the threshold value from being used for phase tracking, Signal processing method for an ultrasonic biometric device that realizes prevention of phase tracking. 2. An ultrasonic wave is radiated toward an object inside the body,
In an analysis means for detecting an ultrasonic signal reflected from the object, determining the instantaneous position of the object using the amplitude and phase of the detected signal, and precisely tracking the displacement movement of the object. , A signal processing method for an ultrasonic biometric measuring apparatus which realizes more accurate phase tracking by statistically examining the variation of the phase of the detected signal on the time axis and setting the vicinity of the optimum value as the tracking start point. 3. The ultrasonic wave is radiated toward an object inside the body,
In an analysis means for detecting an ultrasonic signal reflected from the object, determining the instantaneous position of the object using the amplitude and phase of the detected signal, and precisely tracking the displacement movement of the object. A signal processing method for an ultrasonic biometric measuring apparatus, which prevents the tracking accuracy from being deteriorated by overlapping adjacent reception signals after detection by cutting out signals from each reflection position before detection and processing each signal. 4. An ultrasonic wave is radiated toward an object inside the body,
In an analysis means for detecting an ultrasonic signal reflected from the object, determining the instantaneous position of the object using the amplitude and phase of the detected signal, and precisely tracking the displacement movement of the object. , The signal from each reflection position is cut out before low-pass filtering in the detection process,
A signal processing method for an ultrasonic biometric measuring apparatus, which prevents the reception accuracy from being deteriorated due to overlapping of adjacent reception signals after detection by performing signal processing on each of them. 5. An ultrasonic wave is radiated toward an object inside the body,
In an analysis means for detecting an ultrasonic signal reflected from the object, determining the instantaneous position of the object using the amplitude and phase of the detected signal, and precisely tracking the displacement movement of the object. , By using the detected signal up-sampled to the time resolution equivalent to the required displacement resolution for the analysis, the detected signal can be accurately displaced from the first point to the next point when the next data is analyzed. A signal processing method for an ultrasonic living body measuring apparatus, which can be analyzed by. 6. Emitting ultrasonic waves toward an object inside the body,
In an analysis means for detecting an ultrasonic signal reflected from the object, determining the instantaneous position of the object using the amplitude and phase of the detected signal, and precisely tracking the displacement movement of the object. By acquiring the clock of the ultrasonic measurement device at the same time as the received signal and obtaining the time accuracy of the trigger signal for starting the reception from the phase of the acquired clock signal, it is possible to eliminate the time inaccuracy that depends on the device. Signal processing method for ultrasonic biometric device. 7. An ultrasonic wave is radiated toward an object inside the body,
In an analysis means for detecting an ultrasonic signal reflected from the object, determining the instantaneous position of the object using the amplitude and phase of the detected signal, and precisely tracking the displacement movement of the object. , Acquire a signal that is the sum of the clock of the ultrasonic measurement device and the received signal, find the amplitude and phase of the waveform that is detected by using the signal as the carrier signal for the clock frequency and the received signal frequency, and obtain the phase of the acquired clock signal. A signal processing method for an ultrasonic biometric measuring apparatus capable of eliminating time inaccuracies depending on equipment by obtaining the time accuracy of a trigger signal for starting reception from the device.