JPH06225883A - Ultrasonic image pickup device - Google Patents

Abstract

PURPOSE:To unify the sensitivity of received beams in an ultrasonic image pickup device having multiple reception phasing sections and generating multiple received beams in each transmission/reception of an ultrasonic beam. CONSTITUTION:An ultrasonic image pickup device is provided with three or more reception phasing sections 4a-4c and a coefficient unit changing the weighting of the received signal for the channel of each vibrator element of one or more array-type probes 1 at least generating the dispersion of the ultrasonic reception sensitivity among these reception phasing sections 4a-4c to control the amplitude. The sensitivity distribution of the received signal outputted from the three or more reception phasing sections 4a-4c is unified by the control of an imaging device 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic wave which transmits an ultrasonic beam into an object such as a living body using an array type probe and receives a reflected echo signal from the object to visualize it. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging apparatus, for example, an ultrasonic diagnostic apparatus, and more particularly, to uniformize the sensitivity of each received beam in an apparatus that has a plurality of received wave phasing units and generates a plurality of received beams by transmitting and receiving an ultrasonic beam once The present invention relates to an ultrasonic imaging device that can perform.

[0002]

2. Description of the Related Art A conventional ultrasonic imaging apparatus of this type is shown in FIG.
As shown in FIG. _1, an array type probe 1 in which a plurality of transducer elements 1 1 to ₁ m are arranged to transmit and receive ultrasonic waves to and from an object, and a high frequency pulse is supplied to the array type probe 1 and the array type The ultrasonic transmission / reception unit 2 that amplifies the echo signal received by the probe 1 and the generation timing of the high frequency pulse supplied via the ultrasonic transmission / reception unit 2 are the ultrasonic beams transmitted from the array type probe 1. Ultrasonic wave reception by giving a predetermined delay time to the reception echo signal input via the ultrasonic wave transmission / reception unit 2 and by adding the phases so that they are aligned with each other. Two wave receiving and phasing units 4a and 4b for controlling the sensitivity distribution and the wave receiving and phasing unit 4
It was provided with an imaging device 5 for inputting received echo signals from a and 4b to form an image of the object and a display device 6 for displaying the image signal from the imaging device 5. The array-type probe 1 is formed by arranging m transducer elements 1 ₁ to 1 m in a line, and n transducer elements 1 i to 1 n (i = 1, 2) are arranged in each row. , ..., N; n ≦ m) to sequentially transmit a high frequency pulse signal to generate an ultrasonic wave. In addition, the ultrasonic transceiver 2
Has a built-in transceiver 2 ₁ to 2n of n channels corresponding to the n-number of oscillator elements 1I～1n. Further, the imaging device 5 includes a scan converter 7 that scan-converts a trajectory of an ultrasonic beam propagation path into a video signal format.
And a control circuit 8 for controlling the operations of the wave phasing unit 3, the wave phasing units 4a and 4b, and the scan converter 7.

As the array type probe 1,
There is a linear scanning type probe or a convex scanning type probe as shown in FIG. 7A, and a sector scanning type probe with a phased array as shown in FIG. 7B. The ultrasonic beam is controlled by controlling a phase of a received signal between the transducer elements by sharing a part of an element group used for receiving a signal processed by each of the two received wave phasing units 4a and 4b. Both receiving and phasing section 4
By slightly differentiating between a and 4b and using a part of the element group in any scanning mode at the time of transmission, there is a peak in the center represented by a Sinc function as shown in FIG. Within the width of the target transmission beam 9, two reception beams 10a and 10b which are slightly narrower and symmetric to the transmission beam 9 are formed. Here, in the case of the sector scanning method, for example, the repetition frequency of ultrasonic waves is 4 KH.
When the image is formed with z, the angle of view of 60 degrees, and the angle pitch of 0.5 degree, the image can be updated about 60 times per second by parallel reception of the two ultrasonic beams 10a and 10b.

In FIG. 6, n transducer elements of the array-type probe 1 having a number of elements of m are ultrasonic transducers 2
7 are connected to the transmitters / receivers 2 ₁ to 2 n for n channels, respectively, but in the case of the linear scanning or the convex scanning shown in FIG. 7A, among them, (i + k) to (i + n−k)
(However, 1 ≦ i ≦ m−n, 0 ≦ k <n / 2) -th transducer element is used for wave transmission, and i-
The received echo signal of the (i + n-1) th transducer element is subjected to phasing processing, and the second wave receiving and phasing unit 4b performs (i + 1) to (i +).
If the received echo signal of the (n) th transducer element is subjected to phasing processing, the relationship shown in FIG. 8A can be created.
In the case of sector scanning by the phased array shown in FIG. 7B, this relationship is based on the order of not only the element number of the transducer element but also the resolution of the azimuth angle θ of fan-shaped scanning of the ultrasonic beam as a unit. If it applies to the transmission and reception,
The same applies as above. It is known that the above-described relationship between the distribution of the power of the ultrasonic wave or the sensitivity of the ultrasonic wave for each element and the beam shape in the θ direction are mutually Fourier-transformed and are uniquely determined. Therefore, in the following, the shape of the ultrasonic beam will be representative.
The characteristic of ultrasonic wave transmission / reception in the apparatus shown in FIG. 6 is that the total sensitivity of transmission / reception of two ultrasonic waves by the two wave receiving and phasing units 4a and 4b is the beam shape 11a shown in FIG. 8 (b). , 11b, the curve has a symmetrical distribution shape. In this case, each ultrasonic beam 11a,
The asymmetry of 11b itself is relatively small and can be ignored.

[0005]

However, in such a conventional ultrasonic imaging apparatus, if the number of a plurality of wave receiving and phasing sections is increased and the number of received beams is increased, the following problems occur. Occurs. That is, for example, if the number of wave-reception phasing units is three and the number of wave-reception beams is three (10a, 10b, 10c) as shown in FIG. 8C, the center wave-reception beam 10c is transmitted. Since it is arranged so as to overlap with the center of the wave beam 9, as shown in FIG. 7D, the ultrasonic wave beam 1 in the center of the total ultrasonic wave transmission / reception sensitivity of the three ultrasonic wave beams 1
1c was higher than the ultrasonic beams 11a and 11b on both sides, and the uniformity was lost. Similarly, for example, assuming that the number of wave receiving and phasing units is four, the number of wave receiving beams is four (10a, 10b, 10c, 1) as shown in FIG. 8 (e).
0d), the two receiving beams 10c, 1 in the central part
Since 0d is arranged in a state closer to the center of the transmitted beam 9, as shown in (f) of the figure, the two ultrasonic beams in the central portion in the total sensitivity of transmission and reception of the four ultrasonic beams. 11c and 11d are ultrasonic beams 11 on both sides
It was higher than a and 11b, and the uniformity was sometimes lost as described above. Therefore, in such a state, the display device 6
When an ultrasonic image is displayed on the screen, a bright and dark stripe pattern appears every other scanning line or every other scanning line of the image, and the contrast resolution may decrease. For this reason, the image becomes difficult to see, and for example, in the ultrasonic diagnostic apparatus, a good diagnostic image cannot be obtained, and the diagnostic efficiency may decrease.

In view of the above, the present invention addresses such a problem, and in a device which has a plurality of wave phasing units and generates a plurality of wave receiving beams by transmitting and receiving an ultrasonic beam at each time, An object of the present invention is to provide an ultrasonic imaging apparatus that can make the sensitivity of a wave beam uniform.

[0007]

In order to achieve the above object, an ultrasonic imaging apparatus according to the present invention comprises an array type probe in which a plurality of transducer elements are arranged and which transmits and receives ultrasonic waves to and from an object. The ultrasonic transmission / reception unit that supplies a high frequency pulse to the array type probe and amplifies the echo signal received by the array type probe, and the generation timing of the high frequency pulse supplied via the ultrasonic transmission / reception unit are described above. An ultrasonic beam transmitted from the array type probe is controlled so that the ultrasonic beam is focused on an object, and a phase is given to the received echo signal input through the ultrasonic wave transmitting / receiving unit with a predetermined delay time. Of a plurality of wave phasing units that control the ultrasonic wave receiving sensitivity distribution by aligning and adding the received echo signals from the wave phasing units to form an image of the object. And this visualization equipment In the ultrasonic imaging apparatus including a display device for displaying a video signal from the above, the three or more wave receiving and phasing units are provided, and at least the ultrasonic wave receiving sensitivity among these wave phasing units varies. One or a plurality of them are provided with a coefficient unit that controls the amplitude by changing the weighting of the received signal for each channel of each transducer element of the array-type probe, and the above three elements are controlled by the above-mentioned imaging device. The sensitivity distribution of the received signal output from the above-mentioned wave phasing unit is made uniform.

[0008]

The ultrasonic image pickup device constructed as described above is provided with one or a plurality of coefficient units provided inside at least one of the wave receiving and phasing units in which the ultrasonic wave receiving sensitivity varies. The amplitude of the received signal is controlled by changing the weight of the received signal for each channel of each transducer element of the array type probe, and the reception output from the above three or more wave phasing units is controlled by the imaging device. It operates to make the signal sensitivity distribution uniform. As a result, the sensitivity of each of the plurality of received beams can be made uniform.

[0009]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of an ultrasonic imaging apparatus according to the present invention. This ultrasonic imaging apparatus transmits an ultrasonic beam into an object such as a living body using an array type probe and receives and echoes a reflected echo signal from the object, as shown in the figure. As described above, the array type probe 1, the ultrasonic wave transmission / reception unit 2, the wave transmission phase matching unit 3,
A plurality of wave receiving and phasing units 4a, 4b, 4c and an imaging device 5
And a display device 6.

The array-type probe 1 has a plurality of transducer elements arranged in an array and transmits and receives ultrasonic waves to an object. For example, m transducer elements 1 ₁ to 1 m are arranged in a row. The transducers are arranged in the shape of n and sequentially move to n transducer elements 1i to 1n each to transmit a high frequency pulse signal to generate an ultrasonic wave. In addition, the ultrasonic transceiver 2
A high-frequency pulse is supplied to the array-type probe 1 and an echo signal received by the array-type probe 1 is amplified. Inside the array-type probe 1, n corresponding to the n transducer elements 1i to 1n are provided. and a transceiver 2 ₁ to 2n of channels.

The transmission phase adjusting unit 3 controls the generation timing of the high frequency pulse supplied through the ultrasonic transmission / reception unit 2 so that the ultrasonic beam transmitted from the array type probe 1 is focused on the object. The shape of the ultrasonic beam is controlled by controlling the phase or delay time of the high frequency pulse signal. In addition, the plurality of wave receiving and phasing units 4a to 4c control the ultrasonic wave receiving sensitivity distribution by giving a predetermined delay time to the received echo signals input via the ultrasonic wave transmitting / receiving unit 2 and aligning and adding the phases. To do.

The imaging device 5 receives the received echo signals output from the wave-receiving and phasing units 4a to 4c to form an image of the object, and has an ultrasonic beam inside it. A scan converter 7 for scanning and converting the path of the propagation path into a video signal format, a transmission wave phasing unit 3, wave reception phasing units 4a to 4c, and a control circuit 8 for controlling the operation of the scan converter 7 are provided. . further,
The display device 6 receives the video signal output from the visualization device 5 and displays it as an ultrasonic image, and is composed of, for example, a television monitor.

Here, in the present invention, the three wave-reception phasing units (4a, 4b, 4c) are provided, and at least the ultrasonic wave reception sensitivity among the wave-reception phasing units 4a to 4c varies. The coefficient unit 1 which will be described later
2 _{1 to} 12n are provided. That is, as shown in FIG. 2, an n-channel coefficient multiplier 12 is provided inside the third middle wave-reception phasing unit 4c among the three wave-reception phasing units 4a to 4c.
_{1 to} 12n, a cross point switch 13 having n channels as inputs and p channels as outputs, and tapped delay lines 14 _{1 to} 14p for p sections are provided. The coefficient units 12 _{1 to} 12 n change the weighting of the received signal for each channel of the n-channel transducer elements ₁ i to 1 n of the array type probe 1 and control the amplitude thereof, as shown in FIG. In accordance with the coefficient control signal from the control circuit 8 in the imaging device 5, the amplitude ratio of each channel is changed every moment, and the phasing addition processing is performed to obtain the three wave receiving phasing units 4a to 4a.
The sensitivity distribution of the output signal from 4c is made uniform. Further, the cross point switch 13 outputs the received echo signals input from the coefficient units 12 ₁ to 12 n to p
Switch to channel output and tap delay line 14 ₁
~ 14p. Further, the tapped delay lines 14 _{1 to} 14 p give a predetermined delay time to the reception echo signal selectively input to the input terminal of the delay section which is the required delay time by the cross point switch 13,
Phased addition is performed. Then, as shown in FIG.
When three ultrasonic wave beams are received in parallel by providing three wave phasing units (4a to 4c), the number of image updates per second is increased to about 90 times, which is 1.5 times the conventional value shown in FIG. can do.

Next, the operation of the ultrasonic image pickup device having such a configuration will be described. First, the m-element array-type probe 1 shown in FIG. 1 emits ultrasonic waves from 2k elements of m elements by a high-frequency pulse signal of, for example, 2k channels supplied from a multi-channel ultrasonic wave transmitting / receiving section 2. As a beam, it propagates inside an object such as a living body. At this time, focusing on the single transmission operation during the linear scanning or the convex scanning corresponding to FIG. 7A, the ultrasonic wave transmitting / receiving unit 2 detects the ultrasonic beam from the wave phasing unit 3 within the object. By (i + k) to (i + n-) by a timing signal generated in a phase controlled to focus
The k) th transducer element generates a high frequency pulse signal so as to emit an ultrasonic wave. Note that this relationship is shown in FIG.
The same applies to the case of sector scanning by the phased array corresponding to.

Next, the ultrasonic beam thus ejected is
The echoes propagating through the object and reflected or scattered by the acoustic discontinuity in the object, and the returned echoes are received by the transducer elements 1 _{1 to 1} m of the array type probe _{1 to} generate electricity. It is converted into a signal, input to the multi-channel ultrasonic wave transmitting / receiving unit 2 and amplified. Next, the amplified reception echo signal is input to the first to third reception phasing units 4a to 4c, and for example, the phase of the reception echo signal of n channel is controlled every time from transmission, As shown in FIG. 3 (a), three different directions or parallel receiving beams 10a, 10b and 10c 'are formed within the width of the transmitting beam 9. For example,
The first wave receiving and phasing unit 4a receives the echo signal from the i to (i + n-2) th oscillator element, and the second wave receiving and phasing unit 4b receives the (i + 2) to (i + n) th oscillator. With respect to the received echo signals from the elements, the third wave receiving and phasing unit 4c performs phasing addition processing on the received echo signals from the (i + 1) to (i + n-1) th transducer elements, respectively.

At this time, in the conventional apparatus, the total sensitivity of transmission and reception of the ultrasonic beam 11c formed by the third wave receiving and phasing section 4c located in the center is as shown in FIG. And higher than the ultrasonic beams 11a and 11b formed by the second wave receiving and phasing units 4a and 4b,
In the third wave receiving and phasing unit 4c of the present invention, as shown in FIG.
As shown in, the coefficient units 12 _{1 to} 12 n for controlling the amplitude by changing the weighting for the received echo signal for each channel.
By changing the amplitude ratio of each channel momentarily, as shown in FIG. 3 (a), the receiving beam 10c 'formed by the third receiving and phasing unit 4c is provided on both sides. The output is set to be lower than the received beams 10a and 10b by a predetermined amount. As a result, the reception beam 10c 'arranged so as to overlap the center of the transmission beam 9 in FIG. 3 (a).
The total sensitivity of transmission and reception is lower than that of the conventional one as shown by 11c 'in FIG.
Three ultrasonic beams 11a, 11b formed by 4c,
The sensitivity of 11c 'and the beam shape can be matched and uniformized.

After that, the received echo signals output from the respective wave-receiving and phasing units 4a to 4c are input to the imaging device 5 to form an image, and the image signal output from the imaging device 5 is as follows. Input to the display device 6, and an ultrasonic image of the object is displayed on the screen of the display device 6.

FIG. 4 is a block diagram showing another embodiment of the present invention. In this embodiment, four wave-reception phasing units (4a, 4
b, 4c, 4d) and the wave receiving and phasing unit 4
Among the a to 4d, at least inside the third and fourth wave receiving and phasing units 4c and 4d at the center where the ultrasonic receiving sensitivity varies, as in the case shown in FIG.
2 _{1 to} 12n are provided. The operation in this case is as shown in FIG.
The same operation as in the apparatus shown in FIG.
The four receiving beams 10 by the individual wave phasing units 4a to 4d.
a, 10b, 10c ', 10d' are formed, but the receiving beams 10c ', 10d' formed by the third and fourth receiving and phasing sections 4c, 4d are formed on both sides of the receiving beam 1
The output is reduced by a predetermined amount from 0a and 10b. As a result, the total transmission and reception sensitivities of the two receiving beams 10c 'and 10d' in the central portion arranged closer to the center of the transmitting beam 9 in FIG. 5A are shown in FIG.
11c 'and 11d' are lower than before,
As a result, the sensitivities and beam shapes of the four ultrasonic beams 11a, 11b, 11c ', and 11d' formed by the four wave-phasing units 4a to 4d can be matched and made uniform.

In the above description, the case where three or four wave phasing units are provided has been described, but the present invention is not limited to this, and five or more wave phasing units may be provided if necessary. Further, in the embodiment shown in FIG. 1, only inside the third wave receiving and phasing unit 4c, in the embodiment shown in FIG. 4, the third and fourth wave receiving and phasing units 4c.
c, only in the 4d, it is assumed in which a coefficient multiplier 12 ₁ ~12n of n-channel shown in FIG. 2, respectively in the interior of all the received wave phasing section coefficient multipliers 12 ₁ ~12n provided, The amplitude may be controlled by changing the weighting of the received signal for each channel of the transducer elements 1 1 to ₁ m of the array type probe 1. Further, the plurality of wave phasing units shown in FIGS. 1 and 4 are provided with an A / D converter for converting an analog reception echo signal into a digital signal therein, and
A digital circuit may be configured to digitally process a signal by providing an arithmetic processing unit that performs a phasing process using the digital signal. In this case, the internal circuits of the plurality of wave receiving and phasing units can be configured by a dedicated IC, and the circuit scale can be reduced. Further, the present invention is not limited to the ultrasonic diagnostic apparatus and can be applied to an imaging apparatus using ultrasonic waves such as a sonar or an ultrasonic flaw detector.

[0020]

Since the present invention is constructed as described above,
The sensitivity of each received beam can be made uniform in an apparatus that has a plurality of received wave phasing units and generates a plurality of received beams by transmitting and receiving an ultrasonic beam each time. Therefore, in the ultrasonic image displayed on the screen of the display device, contrast resolution can be improved without causing bright and dark stripes due to the scanning lines as in the conventional case. As a result, the image becomes easier to see, a good diagnostic image can be obtained, for example, in the ultrasonic diagnostic apparatus, and the diagnostic efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an ultrasonic imaging apparatus according to the present invention,

FIG. 2 is a block diagram showing an internal configuration of a wave phasing unit,

FIG. 3 is a graph showing a directivity of a transmission beam, a reception beam, and a transmission / reception total sensitivity distribution for explaining the operation of the present invention;

FIG. 4 is a block diagram showing another embodiment of the present invention,

FIG. 5 is a graph showing a directivity of a transmission beam, a reception beam, and a transmission / reception total sensitivity distribution for explaining the operation of the other embodiment.

FIG. 6 is a block diagram showing a conventional ultrasonic imaging apparatus,

FIG. 7 is an explanatory diagram showing a relationship between an array type probe and beam scanning,

FIG. 8 is a graph showing the directivity of a transmission beam, a reception beam, and a total transmission / reception sensitivity distribution for explaining the operation of the conventional device.

[Explanation of symbols]

1 ... array probe, ₁ 1 to 1 m ... vibrator element, 2 ...
Ultrasonic wave transmission / reception unit, 3 ... Transmission wave phasing unit, 4a to 4d ... Wave reception phasing unit, 5 ... Imaging device, 6 ... Display device, 12 ₁
~ 12n ... Coefficient unit.

Claims (1)

[Claims] 1. An array-type probe having a plurality of transducer elements arranged to transmit and receive ultrasonic waves to and from an object, and a high-frequency pulse is supplied to and received by the array-type probe. The ultrasonic transmission / reception unit for amplifying the echo signal and the generation timing of the high frequency pulse supplied via the ultrasonic transmission / reception unit are controlled so that the ultrasonic beam transmitted from the array type probe is focused on the object. A wave phasing unit,
A plurality of wave receiving and phasing units that control the ultrasonic wave receiving sensitivity distribution by giving a predetermined delay time to the received echo signal input through the ultrasonic wave transmitting / receiving unit and adding the phases by aligning the phases, and the wave receiving and phasing units. In the ultrasonic imaging apparatus, which comprises an imaging device for forming an image of the object by inputting a received echo signal from the imaging unit, and a display device for displaying the image signal from the imaging device, Three or more phasing units are provided, and at least one of these wave phasing units in which variations in ultrasonic wave reception sensitivity occur is provided for each channel of each transducer element of the array type probe. Providing a coefficient unit that controls the amplitude by changing the weighting of the received signal,
An ultrasonic imaging apparatus characterized in that the sensitivity distribution of the reception signals output from the three or more wave rectifying sections is made uniform by the control of the imaging device.