JP4061115B2 - Ultrasonic probe - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to an ultrasonic exploration apparatus capable of detecting a two-dimensional or three-dimensional position of a reflective object such as a fish body, and in particular, improves detection accuracy and resolution while maintaining a simple and inexpensive configuration. The present invention relates to an ultrasonic exploration apparatus.
[0002]
[Prior art]
The conventional simple fish finder radiates ultrasonic waves into the water from an ultrasonic transducer attached to the bottom of the ship, etc., receives the reflected waves generated by reflective objects in the water such as fish, and the time required from transmission to reception, That is, the distance from the time required for the round-trip propagation of the ultrasonic wave to the reflecting object is detected. Since the simplest fish finder cannot detect the arrival direction of the reflected wave, that is, the direction of the reflecting object, it treats all the reflecting objects as if they were directly under the ship.
[0003]
In order to detect not only the distance to the reflecting object but also its orientation, electronic scanning can be performed by arranging multiple ultrasonic transducers and operating them sequentially in the arrangement order, or changing the direction of a single ultrasonic transducer It is necessary to perform a mechanical scan of The above-described electronic scanning configuration requires a large number of ultrasonic transducers, which makes the apparatus complex and expensive. Further, the mechanical scanning configuration requires a mechanical scanning mechanism, so that the apparatus becomes complicated and expensive.
[0004]
In the prior application of the present applicant (Japanese Patent Laid-Open No. 2001-99931), an ultrasonic wave that can detect the two-dimensional or three-dimensional position of a reflective object such as a fish in the sea using a small number of ultrasonic transducers. An exploration device is disclosed. This ultrasonic exploration device receives the reflected wave of the transmitted ultrasonic wave with multiple transducers, and the direction of arrival of the reflected wave from the azimuth function determined by the shape and arrangement of each transducer and the phase difference of the received signal of each transducer Therefore, an azimuth detector that detects the azimuth of the object that has generated the reflected wave is provided.
[0005]
In addition, the apparatus includes a distance detection unit that detects a distance from the ultrasonic wave to the reception of the reflected wave and an amplitude of the received reflected wave and a reflection object, and a reflection intensity. And a display unit that displays two-dimensionally or three-dimensionally the azimuth and distance detected by the detection unit. Thus, in addition to the distance and size to the conventional reflective object, the multidimensional position of the reflective object is detected by detecting the orientation of the reflective object.
[0006]
The principle of azimuth measurement based on the phase difference will be described with reference to FIG. Two ultrasonic transducers (transmission / reception elements) TD1 and TD2 are simultaneously driven by the same transmission signal to irradiate the search region having a certain spread angle with the ultrasonic beam. The reflected signal generated in the fish body Q in the figure is received by the ultrasonic transducers TD1 and TD2, and these received signals are amplified independently and the received signal a₁a₂It becomes. Each received signal has an envelope amplitude of A (t) and an angular frequency of ω,
a₁= A (t) cos (ωt + φ₁)
= A (t) {exp [j (ωt + φ₁)] + exp [-j (ωt + φ₁)]} ... (1)
a₂= A (t) cos (ωt + φ₂) =
= A (t) {exp [j (ωt + φ₂)] + exp [-j (ωt + φ₂)]} ... (2)
It is.
[0007]
Here, as shown in FIG. 7, assuming that the orientation of the reflector is θ, the interval between the ultrasonic transducers is μ, and the wave number of the ultrasonic wave is k (= 2π / λ, λ: wavelength), the phase difference of the received signal φ₁-φ₂For (= Δφ)
Δφ = φ₁-φ₂= k ε ≒ k μsin θ ≒ kμθ (3)
The relationship is established. In addition, td in FIG. 7 is the time required for propagation of the ultrasonic signal between the transmission and reception signals corresponding to the distance to the reflection object, where L is the distance to the reflection object and c is the underwater propagation speed of the ultrasonic wave, td = 2 L / c.
[0008]
FIG. 8 shows the configuration of the phase difference type ultrasonic survey apparatus. In response to an activation command from the control unit CNT, the transmission unit TX generates a transmission electric signal and drives the two ultrasonic transducers TD1 and TD2 simultaneously. D1 and D2 are reverse connection diodes for separating transmission and reception. The reflected signal from the fish body Q is received by the transducers TD1 and TD2, respectively, amplified independently, and the signal a₁a₂It becomes.
[0009]
The signal converter SC receives the received signal a₁a₂Is the complex phase signal c₁, C₂Convert to In the signal converter SC, the received signal a₁, A₂And the reference signal d from the CNT are multiplied by the signal b₁, B₂Get. Here, each signal is a complex signal,
d = exp [-j ωt]
b₁= A (t) {exp (jφ₁) + Exp [-j (2ωt + φ₁)]}
b₂= A (t) {exp (jφ₂) + Exp [-j (2ωt + φ₂)]}
It is.
[0010]
This signal b₁, B₂From which the signal obtained by removing the 2ω component by the low-pass filter is c₁, C₂These are complex phase signals
c₁= A (t) exp (jφ₁)
c₂= A (t) exp (jφ₂)
It is.
[0011]
This signal c is obtained by the phase difference calculation unit ARG.₁, C₂Is calculated, and the argument g is calculated. Therefore, the output g of ARG is
g = Arg [c₁c₂ ^*] = φ₁-φ₂= Δφ
It becomes. Here, Arg [] is an operator for calculating the argument of the complex number.
[0012]
Thus, the phase difference Δφ between the signals is obtained, and thus the direction θ in which the fish exists is
θ ≒ Δφ / (kμ)
It is obtained. The two-dimensional position of the reflecting object is determined from this azimuth angle θ and the ultrasonic wave propagation time td from when the ultrasonic wave is transmitted until the reflected signal arrives.
[0013]
In the amplitude calculation unit AMP, the complex phase signal c₁, C₂Are added by an adder to obtain a signal h. This signal h is
h = c₁ + c₂= A (t) [exp (jφ₁) + Exp (jφ₂)]
It is. Further, a complex absolute value of the signal h is obtained and set as an amplitude signal s. Therefore, this signal s is
s = lh l = A (t) l exp (jφ₁) + exp (jφ₂) l
= 2A (t) cos {(φ₁-φ₂) / 2}
It is.
[0014]
Here, when considering a normal narrow beam received signal u by large aperture reception in which both transmitting and receiving elements are simply connected in parallel, the received signal a₁And a₂Given by the sum of
u = a₁+ A₂
= A (t) cos (ωt + φ₁) + A (t) cos (ωt + φ₂)
= 2 A (t) cos {(2ωt + φ₁+ φ₂) / 2} cos {(φ₁-φ₂) / 2}
It is. The relationship between s and u is that the amplitude signal s is an envelope 2A (t) cos {(φ of the received signal u by large aperture reception in which both transducer elements are connected in parallel.₁-φ₂) / 2}.
[0015]
Therefore, by using s as signal intensity information displayed on the display unit DISP, high sensitivity and sharp directivity due to a large aperture can be used. By displaying the reflected signal intensity s obtained as described above at the two-dimensional position of the measured reflector, the underwater situation is rendered.
[0016]
Using this principle, a configuration in which the ultrasonic transducers TD1 and TD2 in FIG. 7 are directed vertically downward is known. A display example of the two-dimensional in-plane fish position in this configuration will be described with reference to FIG. In this screen, (a) is a normal fish search video, a1 to a3 are echoes of a single fish, a4 is the seabed, and t is time. On the other hand, (b) is a sector sectional view according to the present invention showing the underwater situation in the hull lower xy plane. Here, b1 is an image of a single fish existing in the cross section, the azimuth angle is given from θ, the distance is given from the propagation time of the ultrasonic wave, and the attributes such as the luminance, color, and shade of the video are given from the amplitude s of the received signal. It is done. The image shown in b1 on the sector sectional view corresponds to the fish displayed in a1 in the normal fish search image display. Further, b4 on the sector sectional view is a schematic shape of the seabed. Further, the screen (c) is an image of the xt cross section at the specific depth y1 selected by the cursor.
[0017]
Here, c1 and c3 are images of the fish existing on the selected cross section, and correspond to the fish of a1 and a3. On the other hand, since a2 is out of the plane of depth y1, it is not displayed on the screen (c). By displaying such screens (a), (b), and (c) in parallel on the same screen, the existence position of the fish body can be grasped three-dimensionally. As described above, the basic configuration of the apparatus is realized.
[0018]
Furthermore, using this principle, a configuration is also known in which the ultrasonic transducers TD1 to TD4 shown in FIG. 10 are directed vertically downward as shown in FIG. The apparatus configuration in this configuration is as shown in FIG. 12, and four ultrasonic transducers TD1 to TD4 are installed. M1 to M4 are multipliers, and LPF1 to LPF4 are low-pass filters. The azimuth in the yz plane is determined by the phase difference between the received signals of the transducers TD1 to TD2, and the azimuth in the xy plane is determined from the phase difference between the received signals of the transducers TD3 to TD4. An azimuth angle in space is determined.
[0019]
An example of a screen for displaying the position of the fish body in the three-dimensional space based on this configuration is as shown in FIG. In this display screen, (a) is a screen for displaying a projected image on the yz plane, a1 to a2 are echoes of a single fish, and a3 is a seabed. On the other hand, (b) is a screen that displays a projected image on the xy plane. Here, b1-b2 are images of a single fish, the azimuth is θ, the distance is the sound wave propagation time td, and the display intensity is given by the signal s. The video shown at b1 in (b) corresponds to the fish displayed at a1 in a) display. In addition, (b) b3 in the figure is the schematic shape of the seabed. Further, the screen (c) is an image of the xz cross section at a specific depth y1 selected by the cursor.
[0020]
Here, c1 is an image of the fish existing on the selected cross section, and corresponds to the fish of a1 and b1. On the other hand, since a2 is out of the plane of depth y1, it is not displayed on the screen (c). By displaying such screens (a), (b), and (c) in parallel on the same screen, the existing position of the fish body vertically below can be grasped three-dimensionally.
[0021]
According to the prior art ultrasonic exploration apparatus, it is possible to detect the two-dimensional or three-dimensional position of the reflecting object over a certain angular range such as the heel side direction using a minimum of two ultrasonic transducers. As a result, the multi-dimensional position of the reflecting object can be obtained in a simple and inexpensive configuration without arranging a large number of ultrasonic transducers in the lateral direction or mechanically scanning a single ultrasonic transducer. Can be detected.
[0022]
[Problems to be solved by the invention]
In the above-described conventional ultrasonic exploration apparatus, an area directly under a ship such as a fishing boat is targeted for exploration. For this reason, when a ship finds a school of fish while exploring, there is a problem if operations such as sudden stopping and retreating and preparation for starting fishing become busy. In addition, there is a problem that in a sea area where there are many reefs, obstacles ahead cannot be found to prevent grounding.
[0023]
[Means for Solving the Problems]
  In the ultrasonic exploration apparatus of the present invention that solves the above-mentioned problems of the prior art, the transmitting element radiates an ultrasonic beam obliquely downward and forward of the ship, and the plurality of receiving elements can receive reflected waves generated in front of the ship. By installing, a small number of elementsTheIt is configured to be able to realize a stereoscopic display of a reflective object in front of the water.
[0024]
  Of the present inventionUltrasonic probeAccording to the above, a plurality of receiving elements are arranged at the first and second positions in the ship's side direction (x-axis direction) and the depth direction (y-axis direction), respectively. It is configured to improve the usage efficiency and sensitivity of the ultrasonic transducer by comprising four receiving elements forming four types of pairs selected according to which of the positions of the ultrasonic transducers are arranged. ing.
[0025]
  Of the present inventionUltrasonic probeAccording toThe above direction detectorA first adder circuit for adding the outputs of the pair of receiving elements arranged at the first position in the x-axis direction, and the outputs of the pair of receiving elements arranged at the second position in the x-axis direction. A second addition circuit for adding, a third addition circuit for adding the outputs of the pair of receiving elements arranged at the first position in the y-axis direction, and an arrangement at the second position in the y-axis direction A fourth adding circuit for adding the outputs of the pair of receiving elements, an azimuth calculating unit for calculating an azimuth in the horizontal plane of the reflecting object from the phase difference between the outputs of the first and second adding circuits, and a third , And a depression angle calculating unit for calculating the depression angle in the vertical plane of the reflecting object from the phase difference of the output of the fourth adder circuit so that the azimuth angle and depression angle of the front reflecting object can be detected simultaneously. It is configured.
[0026]
  further,Of the present inventionUltrasonic probeAccording to the first screen display means for displaying an image having an attribute according to the amplitude of the received signal on the xz plane as an image of the reflecting object at a position determined from the distance to the reflecting object and the azimuth angle. By providing a second screen display means for displaying on the yz plane as an image of the reflection object at a position determined from the distance to the reflection object and the depression angle, the azimuth angle and depression angle of the detected front reflection object can be intuitively viewed. It is configured to transmit to the user in a state that can be easily grasped.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
  The present inventionGoodAccording to a suitable embodiment, the third screen displays the image of the reflective object displayed by the first screen display means at the predetermined z coordinate position on the xt display screen that is scrolled over time. A display unit; and a fourth screen display unit that displays an image of a reflective object displayed at a predetermined z coordinate position by the second screen display unit on a yt display screen that is scrolled over time. Thus, the detected azimuth angle and depression angle of the front reflecting object including the past data are transmitted to the user in a state that can be easily grasped intuitively.
[0029]
  The present inventionOtherAccording to the preferred embodiment of the present invention, the means for detecting the amplitude of the received signal by adding the outputs of the four receiving elements is provided, so that the amplitude of the reflected signal can be displayed under a large receiving sensitivity. It is possible to improve detection accuracy and reliability.
[0030]
【Example】
FIG. 1 is a functional block diagram showing the configuration of an ultrasonic exploration apparatus according to an embodiment of the present invention. CNT is a control unit, TX is a transmission unit, D1 to D4 are reverse connection diodes, and TD1 to TD4 are transmission / reception super Sonic transducers, A1 to A4 are signal adders, M1 to M4 are multipliers, LPF1 to LPF4 are low-pass filters, ARG1 and ARG2 are phase difference calculators, AMP2 is an amplitude calculator, and DISP is a display unit.
[0031]
FIG. 2 is a bottom view showing the arrangement of the four ultrasonic transducers TD1 to TD4 in FIG. As shown in (a), each of the four ultrasonic transducers TD1 to TD4 is separated into the ship's side direction (x-axis direction) and the depth direction (y-axis direction). As long as each of the four transducers TD1 to TD4 is separated in the x-axis direction and the y-axis direction, each of the four transducers TD1 to TD4 is not rectangular as shown in FIG. It may be a triangular shape as shown in FIG.
[0032]
Each of the four ultrasonic transducers TD1 to TD4 has a radiated ultrasonic beam obliquely forward of the ship as shown in a front view (a) and a side view (b) of the installation control ship in FIG. It is installed in a state tilted in a vertical plane with respect to the ship bottom so as to propagate downward.
[0033]
Referring to FIG. 1 again, a transmission signal is output from the transmission unit TX under the control of the control unit CNT. This transmission signal is supplied to the four ultrasonic transducers TD1 to TD4 through the reverse connection diodes D1 to D4, and an ultrasonic signal is transmitted from each of them. Ultrasonic signals transmitted from the respective ultrasonic transducers become narrow ultrasonic beams due to mutual interference, and are emitted toward the front obliquely downward of the ship. The center of the beam is directed obliquely downward, but if necessary, the search range can be set so that the beam reaches near the sea surface by using the spread of the beam. The emitted ultrasonic beam is reflected by an underwater reflecting object such as a fish, propagates in the direction opposite to that at the time of transmission, and is received by each of the four ultrasonic transducers TD1 to TD4.
[0034]
Received signal v of ultrasonic transducers TD1-TD4₁~ V_FourAre added by the signal adders A1 to A4, and four combined received signals a₁₁~ A_{twenty two}It becomes. They are
a₁₁= V₁+ V₂
a₁₂= V_Three+ V_Four
a_{twenty one}= V₁+ V_Three
a_{twenty two}= V₂+ V_Four
It is.
[0035]
  Coordinate value x with common center ₂ A combined value a of received signals of a pair of ultrasonic transducers TD1 and TD2 having₁₁And the coordinate value x with the same center ₁ A combined value a of received signals of a pair of ultrasonic transducers TD3 and TD4 having₁₂If the envelope amplitude is A (t) and the angular frequency is ω,
    a₁₁= A (t) cos (ωt + φ₁₁)
        = A (t) {exp [j (ωt + φ₁₁ ] + exp [-j (ωt + φ₁₁)]}
    a₁₂= A (t) cos (ωt + φ₁₂)
        = A (t) {exp [j (ωt + φ₁₂)] + exp [-j (ωt + φ₁₂)]}
  It is.
[0036]
Here, the phase angle φ of the combined received signal₁₁, Φ₁₂As in the case of FIG.₁, The azimuth angle of the reflecting object in the horizontal plane is θ₁The distance in the horizontal plane of a pair of ultrasonic transducers is μ₁(= X₂-X₁), If the wave number of the ultrasonic signal is k (= 2π / λ, λ: wavelength), the phase difference Δφ in the horizontal plane of the combined received signal₁(= φ₁₁−φ₁₂)
Δφ₁= φ₁₁−φ₁₂ = kε₁≒ kμ₁sin θ₁≒ kμ₁θ₁
It becomes.
[0037]
In the multipliers M1 and M2, the received signal a₁₁, A₁₂And the reference signal d supplied from the control unit CNT are subjected to analog multiplication, and the analog multiplication signal b₁₁, B₁₂Is generated. Here, each signal is a complex signal,
d = exp (-jωt)
b₁₁= A (t) {exp (jφ₁₁) + exp [-j (2ωt + φ₁₁)]}
b₁₂= A (t) {exp (jφ₁₂) + exp [-j (2ωt + φ₁₂)]}
It is.
[0038]
These signals b₁₁, B₁₂The signal from which the 2ω component is removed by the low-pass filter is the complex phase signal c₁₁, C₁₂It is. That is,
c₁₁ = A (t) exp (jφ₁₁)
c₁₂ = A (t) exp (jφ₁₂)
It is.
[0039]
In the phase difference calculation unit ARG1, each complex phase signal c₁₁  c₁₂And compute the complex conjugate product of₁Calculate Output of ARG1g₁Is
g₁= Arg [c₁₁ c₁₂ ^*] = φ₁₁−φ_{12 =}Δφ₁
It becomes. Thus, the phase difference Δφ between complex phase signals₁Therefore, the azimuth angle θ in the horizontal plane of a reflective object such as a fish₁Is
θ₁≒ Δφ₁/ (k μ₁)
Is calculated.
[0040]
In the same manner as described above, in the phase difference calculation unit ARG2 of FIG.₂Is calculated. That is, the coordinate value y with the common center₁A combined value a of received signals of a pair of ultrasonic transducers TD1 and TD3 having_{twenty one}And coordinate value y with the same center₂A combined value a of received signals of a pair of ultrasonic transducers TD2 and TD4 having_{twenty two}If the envelope amplitude is A (t) and the angular frequency is ω,
a_{twenty one}= A (t) cos (ωt + φ_{twenty one})
= A (t) {exp [j (ωt + φ_{twenty one} )] + exp [-j (ωt + φ_{twenty one})]}
a_{twenty two}= A (t) cos (ωt + φ_{twenty two})
= A (t) {exp [j (ωt + φ_{twenty two})] + exp [-j (ωt + φ_{twenty two})]}
It is.
[0041]
Here, the phase angle φ of the combined received signal_{twenty one}, Φ_{twenty two}As in the case of FIG.₂, The azimuth angle of the reflecting object in the horizontal plane is θ₂The distance between the pair of ultrasonic transducers in the y-axis direction is μ₂(= Y₂-Y₁), If the wave number of the ultrasonic signal is k (= 2π / λ, λ: wavelength), the phase difference Δφ in the horizontal plane of the combined received signal₂(= φ_{twenty one}−φ_{twenty two})
Δφ₂= φ_{twenty one}−φ_{twenty two} = kε₂≒ kμ₂sin θ₂≒ kμ₂θ₂
It becomes.
[0042]
In the multipliers M3 and M4, the received signal a_{twenty one}, A_{twenty two}And the reference signal d supplied from the control unit CNT are subjected to analog multiplication, and the analog multiplication signal b_{twenty one}, B_{twenty two}Is generated. Here, each signal is a complex signal,
d = exp (-jωt)
b_{twenty one}= A (t) {exp (jφ_{twenty one}) + exp [-j (2ωt + φ_{twenty one})]}
b_{twenty two}= A (t) {exp (jφ_{twenty two}) + exp [-j (2ωt + φ_{twenty two})]}
It is.
[0043]
These signals b_{twenty one}, B_{twenty two}The signal from which the 2ω component is removed by the low-pass filter is the complex phase signal c_{twenty one}, C_{twenty two}It is. That is,
c_{twenty one} = A (t) exp (jφ_{twenty one})
c_{twenty two} = A (t) exp (jφ_{twenty two})
It is.
[0044]
In the phase difference calculation unit ARG2, each complex phase signal c_{twenty one}  c_{twenty two}And compute the complex conjugate product of₂Calculate Output of ARG2g₂Is
g₂= Arg [c_{twenty one} c_{twenty two} ^*] = φ_{twenty one}-φ_{22 =}Δφ₂
It becomes. Thus, the phase difference Δφ between complex phase signals₂(= Φ_{twenty one}−φ_{twenty two}), And therefore the depression angle θ in the vertical plane of a reflective object such as a fish₂Is
θ₂≒ Δφ₂/ (k μ₂)
Is calculated.
[0045]
Reflection azimuth angle θ calculated as described above₁θ₂Then, the three-dimensional position of the reflector is determined from the ultrasonic propagation required time td until the reception signal appears after the reflection signal returns from the ultrasonic transmission.
[0046]
Here, it is assumed that a composite received signal w is received by receiving a large aperture, in which all four ultrasonic transducers TD1 to TD4 are connected in parallel. This combined received signal is received signal v₁To v_FourGiven by the arithmetic sum of
w = v₁+ v₂+ v_Three+ v_Four
= a₁₁ + a₁₂
= A (t) cos (ωt + φ₁₁) + A (t) cos (ωt + φ₁₂)
= 2A (t) {cos (ωt + φ₁₁) + cos (ωt + φ₁₂}
= a_{twenty one} + a_{twenty two}
= A (t) cos (ωt + φ_{twenty one}) + A (t) cos (ωt + φ_{twenty two})
= 2A (t) {cos (ωt + φ_{twenty one}) + cos (ωt + φ_{twenty two}}
= 2A (t) cos {(2ωt + φ₁₁+ φ₁₂) / 2} cos {(φ₁₁−φ₁₂) / 2}
= 2A (t) cos {(2ωt + φ_{twenty one}+ φ_{twenty two}) / 2} cos {(φ_{twenty one}−φ_{twenty two}) / 2}
It is.
[0047]
Since this relationship holds for all times t, for ωt = 0
cos φ₁₁ + cosφ₁₂ = cosφ_{twenty one} + cosφ_{twenty two}
In addition, at ωt = -π / 2,
sin φ₁₁ + sinφ₁₂ = sinφ_{twenty one} + sinφ_{twenty two}
It is.
[0048]
In the amplitude calculation unit AMP2 in FIG. 1, the complex phase signal c₁₁, C₁₂, C_{twenty one}, C_{twenty two}Are added to obtain an addition signal hh. Where the complex phase signal c₁₁And c₁₂The added value of h₁And complex phase signal c_{twenty one}And c_{twenty two}The added value of h₂Then,
h₁= C₁₁+ c₁₂
= A (t) [exp (jφ₁₁) + exp (jφ₁₂)]
= A (t) (cos φ₁₁ + cosφ₁₂ + j sinφ₁₁ + j sinφ₁₂ )
h₂= C_{twenty one}+ c_{twenty two}
= A (t) [exp (jφ_{twenty one}) + exp (jφ_{twenty two})]
= A (t) (cos φ_{twenty one} + cosφ_{twenty two} + j sinφ_{twenty one} + j sinφ_{twenty two} )
= H₁
hh = h₁+ H₂= 2 h₁= 2A (t) [exp (jφ₁₁) + exp (jφ₁₂)]
It is.
[0049]
In this embodiment, if the complex absolute value of the addition signal hh is obtained and this is set as the amplitude signal ss, ss = | hh | = 2A (t) | exp (jφ₁₁) + exp (jφ₁₂) |
= 4A (t) cos {(φ₁₁-φ₁₂) / 2}
It is.
[0050]
In this way, the amplitude signal ss becomes the envelope A (t) cos {(φ of the received signal w by large aperture reception in which all the transducers are connected in parallel.₁-φ₂) / 2}. By displaying the amplitude signal ss as signal intensity information on the display unit DISP, high sensitivity and sharp directivity based on large aperture reception are realized. In particular, even in the three-dimensional measurement as in the present invention, the synthesized reception signal a differs from the reception signal having a caliber of 1/4 by the conventional ultrasonic transducer.₁₁, a₁₂For example, the azimuth angle is calculated for a received signal having a half diameter by two ultrasonic transducers, and the accuracy of azimuth angle calculation is improved. By displaying the reflected signal intensity ss obtained as described above at the two-dimensional position of the measured reflecting object, the underwater situation is rendered.
[0051]
An example of a display screen displayed on the display unit DISP in FIG. 1 is shown in FIG. Azimuth θ in the horizontal plane₁Then, an xz image is formed and displayed based on the three pieces of information of the distance to the reflecting object corresponding to the sound wave propagation time td and the signal intensity ss. This display screen is the sum of the intensities of reflected waves from all the reflecting objects present at respective positions in the y-axis (depth) direction with the same propagation time. In addition, a yz video is displayed adjacent to this. This yz image shows the depression angle θ in the vertical plane.₂And based on three pieces of information: the distance to the reflecting object and the intensity ss of the reflected signal. This display is equal to the sum of the intensities of the reflected waves from all the reflecting objects existing at respective positions in the x direction having the same propagation time.
[0052]
FIG. 5 shows another example of the display screen displayed on the display unit DISP in FIG. Azimuth θ in the horizontal plane₁Then, an xz image is formed and displayed based on the three pieces of information of the distance to the reflecting object corresponding to the sound wave propagation time td and the signal intensity ss. In addition, a yz image is displayed adjacent to the xz image. This yz image shows the depression angle θ in the vertical plane.₂And based on the three pieces of information of the distance to the reflecting object and the signal intensity ss. Depending on the signal strength ss, attributes such as color, brightness, and shade of the displayed video are changed. Up to this point, the display screen is the same as that shown in FIG. In this example of the display screen, the video created in the past with respect to the specific position SP in front is simultaneously displayed as an xt video or a yt video as a function of time t. In this display, the latest video is always displayed at the end, and the past video is scrolled and sent to the left.
[0053]
FIG. 6 shows still another example of the display screen displayed on the display unit DISP in FIG. Azimuth θ in the horizontal plane₁Then, an xz image is formed and displayed at the center based on the three information of the distance to the reflecting object corresponding to the sound wave propagation time td and the signal intensity ss. In addition, a yz video 1 and a yz video 2 are displayed adjacent to the left and right sides of the display screen. These yz image 1 and yz image 2 are represented by a depression angle θ in the vertical plane.₂, The distance to the reflecting object and the signal intensity ss. An image corresponding to a reflective object on the left side of the left and right center in the xz image is displayed on the left side as a yz image 1, and an image corresponding to a reflective object on the right side of the left and right center is displayed on the yz image 2. Is displayed on the right.
[0054]
As described above, the configuration in which the ultrasonic transmitter also serves as the receiver has been exemplified. However, it is also possible to adopt a configuration in which a transmitter separate from the receiver is installed.
[0055]
【The invention's effect】
As described above in detail, in the ultrasonic exploration apparatus of the present invention, the transmitting element radiates an ultrasonic beam obliquely downward in front of the ship, and the plurality of receiving elements can receive reflected waves generated in front of the ship. Since it is a configuration to be installed, there is an effect that it is possible to display a three-dimensional display of an underwater reflective object using a small number of elements.
[0056]
  Main departureClearlyAccording to this, a plurality of receiving elements are arranged at the first and second positions in the ship's side (x-axis) direction and depth (y-axis) direction, respectively. Since it is composed of four receiving elements that form four types of pairs selected according to which one is arranged, there is an advantage that the use efficiency and sensitivity of the ultrasonic transducer are improved.
[0057]
  Main departureClearlyAccording to the first to fourth addition circuits for adding the outputs of the four types of receiving element pairs arranged at the first and second positions in the x-axis and y-axis directions, and the first and second addition circuits. Azimuth angle calculation unit for calculating the azimuth angle of the reflecting object in the horizontal plane from the phase difference of the output of the reflection, and depression angle calculation for calculating the depression angle in the vertical plane of the reflecting object from the phase difference of the output of the third and fourth addition circuits Therefore, there is an effect that the azimuth angle and the depression angle of the reflective object in the water in front can be detected at the same time.
[0058]
  Main departureClearlyAccording to the first aspect, an image having attributes such as luminance, color, and shade according to the amplitude of the received signal is displayed on the xz plane as an image of the reflecting object at a position determined from the distance to the reflecting object and the azimuth angle. Since the screen display means and the second screen display means for displaying on the yz plane as an image of the reflection object at a position determined from the distance to the reflection object and the depression angle, the detected reflection object in the front is provided. There is an advantage that the azimuth angle and the depression angle can be transmitted to the user in a state where it can be easily grasped intuitively.
[0059]
  The present inventionGoodAccording to a suitable embodiment, the third screen displays the image of the reflective object displayed by the first screen display means at the predetermined z coordinate position on the xt display screen that is scrolled over time. A display unit; and a fourth screen display unit that displays an image of a reflective object displayed at a predetermined z coordinate position by the second screen display unit on a yt display screen that is scrolled over time. Since it is a structure, there exists an effect that the detected azimuth angle and depression angle of the front reflective object can be transmitted to the user in a state where it can be easily grasped intuitively including past data.
[0060]
  The present inventionOtherAccording to a preferred embodiment of the present invention, since the means for detecting the amplitude of the received signal by adding the outputs of the four receiving elements is provided, the amplitude of the reflected signal can be reduced with a large receiving sensitivity. It can be displayed, and the effect of improving the accuracy and reliability of detection is achieved.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing a configuration of an ultrasonic survey apparatus according to an embodiment of the present invention.
FIG. 2 is a bottom view illustrating an arrangement of ultrasonic transducers in the ultrasonic exploration apparatus according to the embodiment.
FIGS. 3A and 3B are a front view and a side view showing a state in which an ultrasonic transducer is attached to a ship bottom in the ultrasonic exploration apparatus according to the embodiment.
FIG. 4 is a conceptual diagram illustrating an example of a display screen in the ultrasonic survey apparatus according to the embodiment.
FIG. 5 is a conceptual diagram illustrating another example of a display screen in the ultrasonic survey apparatus according to the embodiment.
FIG. 6 is a conceptual diagram showing still another example of a display screen in the ultrasonic survey apparatus according to the embodiment.
FIG. 7 is a conceptual diagram for explaining the principle of an ultrasonic exploration apparatus that detects the azimuth angle of a reflecting object from the phase difference of ultrasonic reception signals.
FIG. 8 is a functional block diagram showing a configuration of a conventional phase difference type ultrasonic survey apparatus;
FIG. 9 is a conceptual diagram showing an example of a three-dimensional display screen in a conventional phase difference type ultrasonic survey apparatus.
FIG. 10 is a bottom view showing an example of the arrangement of transducers in a conventional phase difference type ultrasonic survey apparatus;
FIGS. 11A and 11B are a front view and a side view showing a state in which a transducer is mounted on a ship bottom in a conventional phase difference type ultrasonic survey apparatus; FIGS.
FIG. 12 is a functional block diagram showing a configuration of a conventional phase difference type ultrasonic survey apparatus;
FIG. 13 is a conceptual diagram showing an example of a three-dimensional display screen in a conventional phase difference type ultrasonic survey apparatus.
[Explanation of symbols]
TD1-TD4 Ultrasonic wave receiving element (Ultrasonic transducer for both transmitting and receiving)
CNT control unit
TX transmitter
D1-D4 Reverse connection diode
SC signal converter
AMP, AMP2 amplitude calculator
ARG, ARG1, ARG2 Phase difference calculator
DISP display
Q Fish
LPF1-LPF4 low pass filter
M1-M4 multiplier
A1-A4 signal adder
SP specific position

Claims (3)

A transmission unit including a transmission element that transmits an ultrasonic signal; a reception unit including a plurality of reception elements that receive a reflected wave from an object of the transmitted ultrasonic signal and output a reception signal; An azimuth detector that detects the azimuth of the object from the arrangement of the receiving elements and the phase difference of the received signals output from each receiving element, and a distance that detects the distance and reflected intensity of the object from the current output and amplitude of the received signals In an ultrasonic exploration apparatus including a reflection intensity detection unit and a display processing unit that displays the object on the screen using the detected azimuth, distance, and reflection intensity as display data,
The transmitting element radiates an ultrasonic beam obliquely below the front of the ship, and the plurality of receiving elements are installed so as to be able to receive reflected waves generated in front of the ship ;
The plurality of receiving elements are arranged at first and second positions in the ship's side direction (x-axis direction) and depth direction (y-axis direction), respectively, and the two types of axes and the two types of positions. And four receiving elements forming four types of pairs selected according to which one of them is common,
The azimuth detecting unit includes a first adder circuit for adding outputs of the pair of receiving elements arranged at the first position in the x-axis direction, and a pair arranged at the second position in the x-axis direction. A second adding circuit for adding the outputs of the receiving elements, a third adding circuit for adding the outputs of the pair of receiving elements arranged at the first position in the y-axis direction, and a second adding circuit in the y-axis direction. And calculating a azimuth angle of the reflecting object in the horizontal plane from a phase difference between the outputs of the pair of receiving elements arranged at the position 2 and the outputs of the first and second adding circuits. An azimuth angle calculation unit, and a depression angle calculation unit that calculates the depression angle in the vertical plane of the reflecting object from the phase difference between the outputs of the third and fourth addition circuits,
A first screen display that displays an image of color, brightness, density, and other attributes according to the amplitude of the received signal on the xz plane as a reflection object image at a position determined from the distance to the reflection object and the azimuth angle. And a second screen display means for displaying on the yz plane arranged adjacent to the xz plane as an image of the reflective object at a position determined from the distance to the reflecting object and the depression angle. And an ultrasonic exploration device. In claim 1 ,
Third screen display means for displaying an image of a reflective object displayed at a predetermined z coordinate position by the first screen display means on an x-t display screen that is scrolled over time; and the second screen display means A fourth screen that displays an image of a reflective object that is displayed at a predetermined z-coordinate position by the screen display unit on a yt display screen that is arranged adjacent to the XT display screen and is scrolled over time. Display means
An ultrasonic exploration apparatus comprising: In claim 1 or 2 ,
The ultrasonic exploration apparatus, wherein the distance / reflection intensity detection unit includes means for detecting an amplitude of the reception signal by adding outputs of the four reception elements .

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