RADIATION ULTRASONIC WAVE VISUALIZATION METHOD AND ELECTRONIC APPARATUS FOR PERFORMING RADIATION ULTRASONIC WAVE VISUALIZATION METHOD

Abstract

A radiation ultrasonic wave visualization method in which an ultrasonic wave radiated by a sound source is visualized, comprises: heterodyne-converting ultrasonic signals in a band of at least 20 KHz or more, which are acquired by an ultrasonic sensor array constituted by a plurality of ultrasonic sensors and converting the ultrasonic signals into a low-frequency signal and thereafter, beamforming the converted low-frequency signals or beamforming the converted low-frequency signals based on resampling signals, thereby handling the low-frequency signals without distorting ultrasonic sound location information to reduce a data handling amount in the beamforming step.

Claims

1. A radiation ultrasonic wave visualization method in which an ultrasonic wave radiated by a sound source is visualized, comprising: heterodyne-converting ultrasonic signals (S1.sub.n) in a band of at least 20 KHz or more, which are acquired by an ultrasonic sensor array (10) constituted by a plurality of (N) ultrasonic sensors (11) and converting the ultrasonic signals S1.sub.n into a low-frequency signal (S2.sub.n) and thereafter; beamforming the converted low-frequency signals or beamforming the converted low-frequency signals based on resampling signals (x.sub.n); and thereby handling the low-frequency signals without distorting ultrasonic sound location information to reduce a data handling amount in the beamforming step.

2. A radiation ultrasonic wave visualization method, comprising: an ultrasonic wave sensing step (S110), in which an ultrasonic sensor array (10) constituted by a plurality (N) of ultrasonic sensors (11) senses ultrasonic wave signals; a first data acquiring step (S120), in which a data acquiring board (DAQ board) acquires ultrasonic signals (S1.sub.n) in an ultrasonic frequency band of 20 KHz to 200 KHz by using ultrasonic signals sensed by the ultrasonic sensor array as a first sampling frequency (f.sub.s1); a low-frequency conversion signal generating step (S130), in which a main board (30) heterodyne-converts the ultrasonic signals S1.sub.n acquired in the first data acquiring step (S120), and generates low-frequency conversion signals (S2.sub.n) in a sound wave band (20 Hz to 20 KHz) based on the ultrasonic signals (S1.sub.n); a second data acquiring step (S140), in which the main board (30) re-samples the low-frequency conversion signals (S2.sub.n) generated in the low-frequency conversion signal generating step (S130) as a second sampling frequency (f.sub.s2), which is smaller than the first sampling frequency (f.sub.s1) to acquire a low-frequency re-sampling signal (x.sub.n); and a sound field visualizing step (S200), in which the main operation board (30) beam-forms the low-frequency re-sampling signals (x.sub.n) and a display device (70) performs the sound field visualization, wherein the ultrasonic sound source is visualized by converting an ultrasonic signal in a band of 20 KHz or more into a sound wave band signal without distorting sound source location information of the sound source of the radiation ultrasonic wave and then re-sampling and beam forming the converted ultrasonic signal.

3. The radiation ultrasonic wave visualization method of claim 2, wherein the first sampling frequency (f.sub.s1) is in a range of 20 KHz to 200 KHz, the second sampling frequency (f.sub.s2) is in a range of 20 Hz to 20 KHz, and the first sampling frequency (f.sub.s1) is selected to be at least two times larger than the second sampling frequency (f.sub.s2).

4. The radiation ultrasonic wave visualization method of claim 2, wherein the sound field visualizing step (S200) includes a sound source calculating step (S50), in which a time delay correction is applied to each of the ultrasonic signals (x.sub.n) using the delay distances calculated above, and sound source values (r.sub.nk) of the virtual plane points are calculated by summing up the time delay correction after the main board including an operation processing device calculates distances between the sensors and virtual plane points using sensor coordinates and virtual plane coordinates; a beam power level calculating step (S60), in which the main board calculates beam power levels (z) of the sound source values (r.sub.nk) generated in the second data acquiring step (S140); and a visual display step (S70), in which the beam power levels (z) calculated in the sound source calculating step (S50) are overplayed and displayed on the display device (70) together with an optical image in the direction in which the sensor array (10) is directed.

5. The radiation ultrasonic wave visualization method of claim 2, further comprising: between the second data acquiring step (S140) and the sound field visualizing step (S200), applying a band pass filter in predetermined frequency bands (f.sub.1 and f.sub.2) to the ultrasonic signals (x.sub.n) acquired in the second data acquiring step (S140).

6. An electronic apparatus performing the radiation ultrasonic wave visualization method of claim 1.

7. An electronic apparatus performing the radiation ultrasonic wave visualization method of claim 2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIGS. 1A and 1B are flowcharts of a radiation ultrasonic wave visualization method according to the present invention.

[0010] FIG. 2 is a configuration diagram of a radiation ultrasonic wave visualization apparatus according to the present invention.

[0011] FIG. 3 is a conceptual view of a radiation ultrasonic wave visualization sensor coordinate and a virtual plane coordinate according to the present invention.

[0012] FIG. 4 is a conceptual view of a radiation time delay summation according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a radiation ultrasonic wave visualization method and an electronic recording medium having a program for performing the radiation ultrasonic wave visualization method, which is recorded therein will be described in detail with reference to the accompanying drawings. FIG. 1 is a flowchart of a radiation ultrasonic wave visualization method according to the present invention, FIG. 2 is a configuration diagram of a radiation ultrasonic wave visualization apparatus according to the present invention, FIG. 3 is a conceptual view of a radiation ultrasonic wave visualization sensor coordinate and a virtual plane coordinate according to the present invention, and FIG. 4 is a conceptual view of a radiation time delay summation according to the present invention.

[0014] As illustrated in FIGS. 1 to 4, a radiation ultrasonic wave visualization method of the present invention as a method of visualizing an ultrasonic wave radiated by a sound source includes heterodyne-converting ultrasonic signals S1.sub.n in at least 20 KHz or more, which are acquired by an ultrasonic sensor array 10 constituted by a plurality of (N) ultrasonic sensors 11 and converts the ultrasonic signals S1.sub.n into a low-frequency signal S2.sub.n in a sound wave band (in detail, 20 Hz to 20 KHz) and thereafter, beamforming the low-frequency signal based on signals x.sub.n acquired by resampling the low-frequency signal beamformed or converted by using the converted low-frequency signals, thereby handling the low-frequency signal without distorting ultrasonic sound location information to reduce a data handling amount in a beamforming step.

[0015] As illustrated in FIGS. 1 to 4, the radiation ultrasonic wave visualization method of the present invention includes an ultrasonic wave sensing step (S110), a first data acquiring step (S120), a low-frequency conversion signal generating step (S130), a second data acquiring step (S140), and a sound field visualizing step (S200).

[0016] First, in the ultrasonic wave sensing step (S110), an ultrasonic sensor array 10 constituted by a plurality N of ultrasonic sensors 11 senses ultrasonic signals. The ultrasonic sensor array 10 constituted by the plurality N of ultrasonic sensors 11 and orienting a radiation sound source senses the ultrasonic signals. The ultrasonic sensor array 10 constituted by the plurality N of ultrasonic sensors 11 and senses ultrasonic signals radiated from a facility while orienting the radiation sound source. The ultrasonic sensor array 10 may have a structure in which a plurality of MEMS microphones, ultrasonic transducers or ultrasonic sensors are mounted on a printed circuit board (PCB) on a planar surface or a flexible PCB on a curved surface. The ultrasonic sensor array 10 is exposed in front of the apparatus and arranged in a forward direction (one direction). Alternatively, the plurality of ultrasonic sensors 11 may be arranged at regular intervals on a sphere or a substantially ball-shaped polyhedron.

[0017] Next, in the first data acquiring step (S120), a data acquiring board (DAQ board) 20 acquires ultrasonic signals S1.sub.n in an ultrasonic frequency band (particularly, 20 KHz to 200 KHz) by using ultrasonic signals sensed by the ultrasonic sensor array 10 as a first sampling frequency f.sub.s1.

[0018] Next, in the low-frequency conversion signal generating step (S130), a main board 30 heterodyne-converts the ultrasonic signals S1.sub.n acquired in step S120, and generates low-frequency conversion signals S2.sub.n in a sound wave band (20 Hz to 20 KHz) based on the ultrasonic signals S1.sub.n.

[0019] Next, in the second data acquiring step (S140), the main board 30 re-samples the low-frequency conversion signals S2.sub.n generated in step S130 as a second sampling frequency f.sub.s2, which is smaller than the first sampling frequency f.sub.s1 to acquire a low-frequency re-sampling signal x.sub.n.

[0020] A detailed equation for the signal x.sub.n is as follows.

[00001]$x_n\left[n\right]=\underset{s=0}{\overset{S-1}{.Math.}}.Math..Math.x_n\left(t\right).Math.\left(t-\frac{s}{f_s}\right)$

[0021] Herein, S: Sample Number, and f.sub.s: Sampling Rate (frequency).

[0022] A step of applying a band pass filter of predetermined ultrasonic frequency bands f.sub.1 to f.sub.2 (preset by the user) to the acquired ultrasonic signals x.sub.n may be further performed. In a filtering data x.sub.nf[s], 1fN.

x.sub.nf[s]=x.sub.n[s].Math.F[s]

[0023] Next, in the sound field visualizing step (S200), the main operation board 30 beam-forms the low-frequency re-sampling signals x.sub.n and a display device 70 performs the sound field visualization. The ultrasonic sound source is visualized by converting an ultrasonic signal in a band of 20 KHz or more into a sound wave band signal without distorting sound source location information of the sound source of the radiation ultrasonic wave and then re-sampling and beam forming the converted ultrasonic signal.

[0024] In the radiation ultrasonic wave visualization method according to the exemplary embodiment of the present invention, the first sampling frequency f.sub.s1 is in a range of 20 KHz (40 KHz) to 200 KHz (400 KHz), and the second sampling frequency f.sub.s2 is in a range of 20 Hz (40 Hz) to 20 KHz (40 KHz), and it is preferable that the first sampling frequency f.sub.s1 is selected to be at least two times larger than the second sampling frequency f.sub.s2 in terms of reduction of a data throughput.

[0025] In the range of the first sampling frequency f.sub.s1 of 20 KHz (40 KHz) to 200 KHz (400 KHz), as the test result, it is possible to acquire ultrasonic sound source location information which is effective and required for the ultrasonic sensor detection performance and machinery failure currently released in this area, rotating machine breakdown, gas pipe gas leakage, and power equipment diagnosis monitoring. Further, as the test result, it can be seen that the data throughput may be appropriately reduced in the range of the sampling frequency f.sub.s2 of 20 Hz (40 Hz) to 20 KHz. If the sampling frequency is too large, more data processing is needed, and if the sampling frequency is too small, the ultrasonic area sound source information is lost.

[0026] <Sound Field Visualizing Step (S200)>

[0027] As described above, in the sound field visualizing step (S1200), the main operation board 30 beam-forms the low-frequency re-sampling signals x.sub.n and the display device 70 performs the sound field visualization, and it will be described in more detail.

[0028] The sound field visualizing step (S200) largely includes a sound source value calculation step (S50) by a time delay sum, a beam power level calculating step (S60), and a visual display step (S70).

[0029] First, in the sound source value calculating step (S50), the main board 30 including an operation processing device calculates distances between the sensors 11 and virtual plane points using sensor coordinates and virtual plane coordinates. Thereafter, time delay correction is applied to each of the ultrasonic signals x.sub.n using the delay distances calculated above, and sound source values r.sub.nk of the virtual plane points are calculated by summing up the time delay corrections.

[0030] FIG. 3 is a diagram illustrating a relationship between the sensor coordinate and the virtual plane coordinate. As illustrated in FIG. 3, a distance d.sub.k between the sensor coordinate (Xs, Ys) and the virtual plane coordinate (Xg, Yg) is calculated as follows. When the distance L is 1 m, the operation of +L.sup.2 is represented by +1 operation.

d.sub.k=X.sub.sX.sub.g).sup.2+(Y.sub.sY.sub.g).sup.2+L.sup.2

[0031] FIG. 4 is a conceptual diagram of a radiation ultrasonic wave visualization time delay summation of the present invention. Subsequently, in the sound source value calculating step (S50), first, a time delay correction is applied to each of the ultrasonic signals xn using the calculated delay distances, and sound source values r.sub.nk of M virtual plane points are calculated by summing up the time delay corrections.

[0032] First, a delay sample number is calculated. The time delay is calculated using a distance between the sensor and the virtual plane and a sound speed and the delay sample number is calculated by the calculated time delay. The details are as follows.

[00002]${}_k=\frac{d_k}{c}.Math..Math.\left(\mathrm{Time}.Math..Math.\mathrm{delay}\right),.Math.N_k=f_s.Math.{}_k=f_s.Math.\frac{d_k}{c}=\frac{f_s}{c}.Math.d_k=C_d.Math.d_k$$C_d=\frac{f_s}{c}$

[0033] Herein, C.sub.d represents a time delay coefficient and c is a sound speed. N.sub.k represents the delay sample number.

[0034] Next, the time delay is compensated by using the delay sample number and summed up. In this case, a correction coefficient for each sensor is applied.

[00003]${\stackrel{}{r}}_{\mathrm{nk}}\left[s\right]=\underset{n=0}{\overset{N-1}{.Math.}}.Math..Math.{}_n.Math.x_{\mathrm{nf}}\left[s\right].Math.\left[s-N_k\right]$${}_n.Math.\text{:}.Math..Math.\mathrm{Weighting}.Math..Math.\mathrm{Factor}$

[0035] Herein, 1nK M. M is the number of all elements in rows and columns on a virtual plane coordinate.

[0036] Next, the beam power level calculating step (S60) for calculating the beam power levels z of the generated sound source values r.sub.nk is performed.

[00004]$z_k=\frac{1}{N}.Math.\underset{S=0}{\overset{S-1}{.Math.}}.Math..Math.{\stackrel{}{r}}_{\mathrm{nk}}^2\left[s\right]$

[0037] In the visual display step (S70), the beam power levels z calculated in step S50 are overplayed and displayed on the display device 70 together with an optical image in the direction which the sensor array 10 faces.

Apparatus

[0038] An apparatus that performs the method of the present invention will be described in detail. The apparatus for performing the method of the present invention includes an ultrasonic sensor array 10, a data acquisition board (DAQ board) 20, a main board 30, a data storage medium 40, a battery 50, a plastic body case 60, and a display device 70.

[0039] As illustrated in FIG. 2, the ultrasonic sensor array 10 is constituted by a plurality N of ultrasonic sensors 11 and senses ultrasonic signals radiated from a facility while orienting the radiation sound source. The ultrasonic sensor array 10 may have a structure in which a plurality of MEMS microphones, ultrasonic transducers or ultrasonic wave sensors are mounted on a printed circuit board (PCB) on a planar surface or a flexible PCB on a curved (three-dimensional) surface, a sphere, a substantially ball-shaped polyhedron, a hemisphere, and a rear-opened convex curved surface.

[0040] An electronic circuit for acquiring the ultrasonic signals x.sub.n using ultrasonic signals sensed from the ultrasonic sensor array 10 as a sampling frequency f.sub.s is mounted on the substrate of the DAQ board 20. The DAQ board 20 performs sampling and may include a signal amplification circuit.

[0041] In the main board 30, an operation processing device 31 that processes digital (alternatively, analog) ultrasonic signals received from the DAQ board 20 is mounted on the substrate and transmits the processed ultrasonic sound source information to the display device 70. The data storage medium 40 stores data processed in the operation processing device 31 of the main board 30.

[0042] The apparatus includes an optical camera 80 for picking up an image of a direction in which the ultrasonic sensor array 10 is directed and transmitting the image to the main board 30. The display device 70 visually displays the data processed by the operation processing unit 31 of the main board 30 and is integrally installed in the plastic body case 60. Alternatively, the display device 70 is integrally fixed to the plastic body case 60 so as to be exposed to the outside of the plastic body case 60.

[0043] The battery 50 supplies electric power to the data acquisition board 20, the main board 30 and the display device 70, and it is preferable that the battery 50 is installed in a detachable and rechargeable state inside the plastic body case 60. However, the battery may be a separate portable rechargeable battery which is located outside the plastic body case 60 and supplies electric power to the data acquisition board 20 and the main board 30 by electric wires. Alternatively, both an internal battery and an external auxiliary battery may be provided and used.

[0044] The plastic body case 60 is formed of a hard material for fixing the ultrasonic sensor array 10, the data acquisition board 20, the main board 30 and the data storage medium 40. The plastic body case 60 supports the array 10 constituted by the plurality of ultrasonic sensors 11 electrically connected to each other, or supports the ultrasonic sensor array 10 by supporting and fixing an ultrasonic sensor array PCB mounted on a flat or curved plate on which the ultrasonic sensors 11 are mounted. The inside of the plastic body case 60 has a hollow chamber, and the data acquisition board 20 and the main board 30 having an operation processing capability are fixedly installed in the hollow chamber.

[0045] The display device 70 visually displays the data processed by the operation processing unit 31 of the main board 30 and is integrally installed in the plastic body case 60. Alternatively, the display device 70 is integrally fixed to the plastic body case 60 so as to be exposed to the outside of the plastic body case 60.

[0046] The present invention includes an electronic recording medium on which a program is recorded for the radiation ultrasound visualization method, wherein the electronic recording medium is an electronic device including a CPU for executing a program, a hard disk on which a program is stored, a stationary memory, a removable memory and the like.

[0047] The present invention has been described in association with the above-mentioned preferred embedment, but the scope of the present invention is not limited to the embodiment and the scope of the present invention is determined by the appended claims, and thereafter, the scope of the present invention will includes various modifications and transformations included in an equivalent range to the present invention.

[0048] Reference numerals disclosed in the appended claims are just used to assist appreciation of the present invention and it is revealed that the reference numerals do not influence analysis of the claims and it should not be narrowly analyzed by the disclosed reference numerals.