JP6116239B2 - Subject information acquisition apparatus and subject information acquisition method - Google Patents

Description

  The present invention relates to a subject information acquisition apparatus and a subject information acquisition method.

  Ultrasound diagnostic devices are attracting attention as subject information acquisition devices because they do not worry about exposure to X-rays. In breast cancer diagnosis (mammography), which is one of the uses, diagnosis (measurement) may be performed in a state where the subject breast is pressed and held. In such a case, ultrasonic transmission / reception for measurement is performed via a holding member that compresses and holds the subject, but due to the difference in acoustic impedance between the holding member and the subject, ultrasonic waves are generated in the holding member. There is a problem that multiple reflection occurs and the multiple reflected ultrasonic waves cause artifacts. In order to solve this problem, Patent Document 1 discloses a technique for obtaining a diagnostic image with reduced artifacts by subtracting an artifact portion caused by multiple reflected ultrasonic waves from an image including artifacts due to multiple reflections. ing.

JP 2009-82450 A

  However, in the image obtained by the apparatus of Patent Document 1, there is a risk that the subject information is lost. The reason is that, from the image obtained from the received ultrasonic wave, the ultrasonic wave received without multiple reflection (the ultrasonic wave that correctly reflects the subject information) and the ultrasonic wave received after multiple reflection (the ultrasonic wave of the artifact factor) It is difficult in practice to accurately separate the) and information that is not an artifact may be removed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a defect in subject information in a subject information acquisition apparatus that obtains subject information through a member and obtains (reconstructs) an image. It is to reduce image degradation due to multiple reflections while suppressing the above.

The present invention that solves the above-described problems includes a plurality of transducers that transmit ultrasonic waves to a subject, receive reflected ultrasonic waves reflected by the subject, and output reception signals;
Control means for controlling the drive of the vibrator;
Signal adjusting means for correcting the received signal received by each transducer;
Have
The signal adjusting means is based on at least one of a drive pattern of the plurality of vibrators, a positional relationship between the plurality of vibrators, and a shape of a member provided between the subject and the vibrator. An object information acquiring apparatus characterized in that a gain for the received signal is set so as to reduce a multiple reflection component included in the reflected ultrasound to be determined.

Another invention for solving the above problem is an information acquisition method for acquiring information of a subject,
With a member having an acoustic impedance different from that of the subject interposed between the plurality of transducers and the subject, the plurality of transducers are driven to transmit ultrasonic waves to the subject, and the subject Receiving the reflected ultrasound reflected by the specimen with the plurality of transducers to obtain a received signal;
Correcting the acquired received signal,
In the correcting step, a multiple reflection component included in the reflected ultrasonic wave determined based on at least one of a driving pattern of the plurality of transducers, a positional relationship between the plurality of transducers, and a shape of the member. The method includes a step of setting a gain for the received signal so as to reduce the received signal.

  According to the present invention, it is possible to obtain an image with reduced loss of subject information while reducing artifacts.

It is a schematic diagram which shows the structure of the subject information acquisition apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the 1st structure of the beam forming part of this invention. It is a schematic diagram which shows the 2nd structure of the beam forming part of this invention. 1 is a schematic configuration diagram of Embodiment 1 of the present invention. It is a figure which shows the pattern of the signal which an aperture element receives. It is the structure schematic of Example 2 of this invention. It is the structure schematic of Example 3 of this invention. FIG. 6 is a diagram illustrating an effect of Example 1. It is a figure showing how to apply a correction pattern and gain. Diagram showing transmission pattern, holding member characteristics, positional relationship of piezoelectric elements, and artifacts

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of a subject information acquisition apparatus according to the present embodiment. The subject information acquisition apparatus according to the present embodiment includes a piezoelectric element 3 that is a vibrator, a holding member 1 that is a member having an acoustic impedance different from that of the subject, a beam forming unit 5 that is a signal adjustment unit, and a vibration. And a transmission processing unit 4 which is a control means for controlling the driving of the child.

  The piezoelectric element 3 as a vibrator transmits ultrasonic waves to a subject, receives reflected ultrasonic waves reflected by the subject, and outputs a reception signal. The holding member 1 is a member that is located between the subject and the piezoelectric element 3 that is a vibrator, and that transmits the ultrasonic waves transmitted by the vibrator and the reflected ultrasonic waves received by the vibrator. The transmission processing unit 4 serving as a control unit controls driving of the piezoelectric element 3 serving as a vibrator. The beam forming unit 5 serving as a signal adjusting unit corrects a reception signal received by the piezoelectric element 3 serving as each transducer. And the correction | amendment which the beam forming part 5 which is a signal adjustment means performs the shape of the holding member 1 which is a member which has an acoustic impedance different from a test object, and the drive pattern of the vibrator | oscillator by the transmission process part 4 which comprises a control means. And based on the positional relationship between the plurality of transducers. As a result, it is possible to obtain an image with reduced loss of subject information while reducing artifacts. This will be described below. In the following, as shown in FIG. 1, a structure including a plurality of piezoelectric elements 3 that are vibrators will be described as a probe 2.

  FIG. 5 (a) receives reflected ultrasonic waves reflected from a reflector located directly below the central portion of the probe using a probe in which piezoelectric elements as a plurality of transducers are arranged in a straight line. It is a figure which shows the reception timing in each piezoelectric element at the time of performing. As shown in FIG. 5 (a), the piezoelectric element located at the center of the probe receives the reflected ultrasonic wave first, then gradually receives the piezoelectric element around the center, and the piezoelectric element at the end ends. Receive. This difference in reception timing occurs due to a difference in distance between the reflector and each piezoelectric element. FIG. 5B is a visualization of the actual measurement data of the reception status, and the white part in the figure shows the strong part of the received reflected ultrasonic wave, and the reflected ultrasonic wave becomes a piezoelectric element toward the right side in the figure. Means that it was reached early (received). On the other hand, FIG. 5C visualizes actual measurement data when receiving a signal of multiple reflection by the holding member, and FIG. 5C transmits ultrasonic waves using a plurality of piezoelectric elements 3. In this case, the timing of driving the piezoelectric element is shifted and the ultrasonic beam is focused directly below the center of the probe. In this case, as shown in FIG. 5 (c), the reflected ultrasonic wave due to the multiple reflection at the holding member first reaches the piezoelectric element at the end of the probe and is received, and thereafter gradually becomes the element at the center. Reaching toward is received. After that, it gradually reaches the piezoelectric element around the center of the probe and is received, and finally reaches the piezoelectric element at the end of the probe and is received. As shown in FIG. Is received in a pattern like X. Although not shown in the figure, as a result of our examination, when transmitting ultrasonic waves using a plurality of piezoelectric elements, when transmitting at the same timing for driving the piezoelectric elements, reflection due to multiple reflection at the holding member The ultrasonic wave first reaches all the piezoelectric elements and is received. After that, it gradually reaches the piezoelectric element at the end from the piezoelectric element at the center of the probe and receives it. As a result, like the alphabet K described above, it is similar to FIG. It turned out that it was received with a simple pattern.

  As described above, when transmitting an ultrasonic wave and receiving a reflected ultrasonic wave through a member having an acoustic impedance different from that of the subject, multiple reflected ultrasonic waves are received in a specific pattern as described above. It became clear from our earnest research. Which pattern (or similar pattern) is received depends on the shape of the member (holding member in this embodiment) interposed between the subject and the piezoelectric element that is the vibrator and the piezoelectric element that is the vibrator. Our study revealed that it was determined depending on the drive pattern and the positional relationship between multiple transducers. Specifically, as described above, the drive pattern at the time of ultrasonic transmission of the piezoelectric elements that are a plurality of transducers is received at the timing when the multiple reflected ultrasound becomes the K pattern in the pattern that simultaneously drives the plurality of transducers. Is done. On the other hand, in the pattern of driving multiple transducers at different timings so that the transmitted ultrasonic waves converge within the subject, the multiple reflected ultrasonic waves are Received at the timing of the X pattern. Similarly, the X pattern, the K pattern can be changed by a change in the shape of a member having an acoustic impedance different from that of the subject and a change in the positional relationship between the plurality of transducers, which are interposed between the subject and the piezoelectric element as the vibrator. Our study has shown that each pattern changes, and this is shown in FIG.

  For details on the relationship between the reception pattern of the piezoelectric element, which is a multi-reflection ultrasonic transducer, and the shape of the member of the acoustic impedance different from the subject, the drive pattern of the transducer, and the positional relationship between multiple transducers Although there are unclear parts, the inventors believe that these all affect the arrival time of the reflected ultrasonic wave to the vibrator. This will be described below.

  It can be seen that the multiple reflection ultrasonic wave reception patterns reach each piezoelectric element at least at two timings. This is because each piezoelectric element receives multiple reflected ultrasonic waves of ultrasonic waves transmitted by itself and multiple reflected ultrasonic waves of ultrasonic waves transmitted by other piezoelectric elements at different timings. These two timings are determined by the time difference when the multi-reflection ultrasonic waves of the ultrasonic waves transmitted by themselves and the multi-reflection ultrasonic waves of the ultrasonic waves transmitted by other piezoelectric elements reach each piezoelectric element, and the main factor determining this time difference is: The inventors consider the shape of the member having an acoustic impedance different from that of the subject, the drive pattern of the vibrator, and the positional relationship between the plurality of vibrators. That is, for example, as shown in FIG. 10, the shape (for example, thickness) of the member having an acoustic impedance different from that of the subject decreases the difference in the round-trip distance within each member of the multi-reflection ultrasonic wave as the thickness increases. The difference between the two timings (time difference) is reduced. As a result, as shown in FIG. 10, if the X pattern, an X pattern with a small opening is obtained. In addition, as shown in FIG. 10, the driving pattern of the transducer is such that, as the transmission focus position is shallower, in other words, the closer the focus position is to the subject, the greater the time difference between the driving timings between the transducers. The timing difference (time difference) also increases. This can also be understood from the fact that when the transmission focus position is deepened, it is similar to plane wave transmission (a pattern in which a plurality of transducers are driven simultaneously). Further, as shown in FIG. 10, the positional relationship between the plurality of transducers is such that each of the multiple reflected ultrasonic waves becomes larger as the interval between the piezoelectric elements that are adjacent transducers is larger or the pitch between the adjacent transducers is larger. Since the difference in the reciprocating distance within the member increases, the difference between the two timings (time difference) also increases. Therefore, by correcting the reception signal output from the vibrator based on these findings, it is possible to efficiently and more accurately correct the noise factor (correct only the noise region), while reducing artifacts, It is possible to obtain an image in which the loss of the subject information is further reduced.

  Next, specific correction contents will be described with reference to FIG.

  FIG. 9A is a diagram for explaining correction when receiving the above-described X-pattern multiple reflection ultrasonic waves. FIGS. 9B and 9C are diagrams illustrating the correction at times t1 and t2, respectively. It is the figure which showed the gain correction with respect to a received signal. As shown in FIG. 9 (b), at time t1, gain correction performed on the received signal by the reflected ultrasonic wave received by the central vibrator is received by the vibrator at the end (opening end). Correction is performed so as to be smaller (gain value is smaller) than the gain correction performed on the received signal by the reflected ultrasonic wave. On the other hand, at time t2, gain correction performed on the received signal from the reflected ultrasonic wave received by the central vibrator is performed on the received signal from the reflected ultrasonic wave received by the end (opening end) vibrator. The gain is corrected so as to be larger than the gain correction performed (the gain value is increased). As described above, at each time, correction corresponding to the shape pattern of the multiple reflected ultrasound obtained based on the shape of the member having an acoustic impedance different from that of the subject, the driving pattern of the transducer, and the positional relationship between the plurality of transducers. By correcting with patterns, artifacts can be reduced efficiently and accurately. In the K pattern shown in FIG. 9 (d), the time t1 is set as shown in FIG. 9 (d) (by setting the time when the multi-reflection ultrasonic wave reaches the central transducer). Artifacts can be reduced by performing the correction shown in 9 (b) and 9 (c). Note that since there is an artifact in the center of each pattern, as shown in FIG. 9 (e), it is sufficient to perform the correction shown in FIG. 9 (b) between times t1 and t3. Can be reduced.

  Next, each structure of the subject information acquisition apparatus of this embodiment is demonstrated in order using FIGS.

  1, a holding member 1 for holding a subject, a probe 2 having a plurality of piezoelectric elements 3, a transmission processing unit 4 for controlling driving of the piezoelectric elements during ultrasonic transmission, and a reception signal output from the piezoelectric elements The beam forming unit 5 for correcting the above is as described above. The object information acquisition apparatus of the present embodiment shown in FIG. 1 preferably has an image processing unit 6 that performs image adjustment such as LOG compression on the received signal corrected by the beam forming unit 5 and the obtained image data. An image display unit 7 to display and a memory 8 that stores a correction pattern in advance for correction performed by the beam forming unit 5 are provided. Next, the operation of each component will be described.

  The transmission processing unit 4 determines a drive delay time when driving each group of piezoelectric elements 3 forming the transmission aperture in order to focus the transmission beam at an arbitrary position. Based on the delay time, an electrical signal is sent from the transmission processing unit 4 to each piezoelectric element 3. Each piezoelectric element 3 generates an ultrasonic wave when it receives an electrical signal, and irradiates the subject with the ultrasonic wave via the holding member 1. For this reason, it is necessary for the holding member 1 to pass ultrasonic waves, and a material that suppresses reflection of ultrasonic waves at the interface between the subject and the holding member 1 is preferable. Specifically, a material having a small difference in acoustic impedance with the subject 9 is preferable. For example, a resin material such as polymethylpentene is preferable. Further, the thickness of the holding member 1 is preferably thinner in consideration of attenuation when ultrasonic waves pass through the holding member 1, but an appropriate thickness is used in order to suppress deformation of the member when holding the subject. Is necessary, and about 5 mm to 10 mm is preferable.

  The ultrasonic waves transmitted toward the subject in this way are reflected by the subject and return to the piezoelectric element 3 as reflected ultrasonic waves. Among these, the reflected ultrasonic waves received by the group of the plurality of piezoelectric elements 3 forming the reception aperture are converted into electric signals and acquired as reception signals. The received signal is corrected (signal processing) in the beamforming unit 5.

  2 to 4 show the configuration of the beam forming unit 5 and the signal processing state performed by each configuration. In the figure, reference numeral 10 denotes a phasing delay unit for aligning the phases of received signals based on the reflected ultrasonic waves received by the piezoelectric elements 3. Reference numeral 11 denotes an element weight adjustment unit that weights and corrects each delayed received signal, and reduces or eliminates signal components based on multiple reflection ultrasonic waves. Reference numeral 12 denotes an adder for summing the corrected received signals. Reference numeral 13 denotes a Hilbert transform unit that performs Hilbert transform on the added signal, and reference numeral 14 denotes a quadrature detection unit for detection.

  The phasing delay unit 10 determines a delay time of the received signal based on information on a position (depth) where the transmitted ultrasonic wave is reflected, and performs a delay process on each received signal. This delay time is determined in consideration of not only the structure of each piezoelectric element 3 constituting the probe 2 and the acoustic characteristics of the subject but also the thickness and acoustic characteristics of the holding member 1.

  The received signal subjected to the delay process is corrected by the element weight adjusting unit 11 using a correction value to which a weight determined in advance by the characteristics of the holding member 1, the drive pattern of the piezoelectric element, and the positional relationship of the piezoelectric element is added as described above. It is corrected. The correction value pattern (hereinafter sometimes referred to as a weight pattern) is set in time series for each reception time and is recorded in the memory 8. 2 and 4 show an example of X pattern correction, and FIG. 3 shows an example of K pattern correction. Since these correction value patterns are as described above, description thereof will be omitted.

  Each corrected received signal (weight adjusted) is summed by the adder 12. Thereafter, the combined signal is subjected to Hilbert transform and quadrature detection in the Hilbert transform unit 13 and the quadrature detection unit 14. Note that the processing method of the beam forming unit 5 here is a phasing addition processing method used in a general ultrasonic diagnostic apparatus, but a technique such as adaptive signal processing is also effective. .

  The data that has undergone these processes is LOG compressed in the image processing unit 6 as shown in FIG. The compressed data is displayed on the image display unit 7. As the image display unit 7, a liquid crystal display, a plasma display, an organic EL display, an FED, or the like can be used.

  Note that a typical correction pattern (weight pattern) by the element weight adjustment unit 11 is both end portions (open end portions) of a plurality of piezoelectric elements as shown in FIGS. 9B and 9C described above. ), Or a pattern in which the weight at the center and both ends of the opening is greater than the other weight. The element weight adjustment unit 11 can also be used for aperture control processing and apodization processing in a general ultrasonic apparatus. However, in the aperture control processing for equalizing the resolution at each depth and the general apodization processing for suppressing the side lobe level, correction is performed so that only the central portion of the aperture is larger than the weights at both ends. This is a different process.

  As described above, the correction pattern for suppressing the multiple reflection represented by the X pattern and the K pattern is the transmission pattern set by the transmission processing unit, the number of the plurality of piezoelectric elements 3 constituting the aperture, and the piezoelectric represented by the pitch. It varies depending on the relationship of the element 3 and the shape (characteristic) information of the holding member such as the thickness, the speed of sound, and the deflection shape. However, it is a highly reproducible phenomenon that is accurately calculated by calculation (or by experiment) if conditions are determined. Incidentally, it is preferable to use a numerical analysis program as a technique for reproducing the reception pattern (correction pattern) of multiple reflection ultrasonic waves by calculation. The reception timing (correction pattern) of the multiple reflection signal can be obtained by using the simulation software that reproduces the transmission / reception of the ultrasonic waveform and setting the relationship between the piezoelectric elements.

  Also, when calculating the reception timing of multiple reflection ultrasonic waves, it is also effective to set a correction pattern by measuring a multiple reflection ultrasonic pattern by experiment instead of calculating as described above. At this time, it is preferable to perform measurement in a state where the subject is not held. This is because the difference in acoustic impedance between the air and the holding member is large, so that it is possible to more clearly grasp the multi-reflection ultrasonic waves.

  As described above, in the present embodiment, correction by the element weight adjusting unit 11 reduces and removes the predicted multiple reflection ultrasound, and the image degradation due to the multiple reflection ultrasound without losing the signal from the subject. Can be reduced.

  Hereinafter, the present invention will be described in detail with specific examples.

  System schematic diagrams of the subject information acquisition apparatus of the present embodiment are shown in FIGS.

  A 128-ch linear probe was used as the probe 2. The piezoelectric element 3 is a piezoelectric element (PZT) having a center frequency of 6 MHz. A resin flat plate made of polymethylpentene having a thickness of 7 mm was used as a holding member for holding the subject. The transmission processing unit 4 generates an ultrasonic wave by transmitting an electric signal that forms a transmission beam at the target focus position to the piezoelectric element 3, and transmits (propagates) the ultrasonic wave to the subject. The propagated ultrasonic waves are reflected / scattered by the subject and received as reflected ultrasonic waves via the holding member 1 by a plurality of piezoelectric elements 3 that form reception openings. In this embodiment, since the reception aperture is formed by a group of 32 piezoelectric elements 3, the image data on the scanning line is obtained from the reception signals from the 32 piezoelectric elements. Then, this received signal is sent to the beam forming unit and subjected to signal processing (correction).

  The received signal subjected to signal processing (correction) is sent to the image processing unit 6 and subjected to LOG compression processing. The data created in the above process is sent to the image display unit 7 including the LCD, and an image is displayed. In this embodiment, an LCD is used as the image display unit 7.

(Operation of beam forming section)
A signal processing process including correction in the beam forming unit will be described with reference to FIGS. The phasing delay unit 10 performs delay processing on the electrical signals (reception signals) received from the 32 piezoelectric elements 3 forming the openings. Here, each received signal is subjected to delay processing based on the delay time calculated from the depth information. Then, the correction process which is sent to the element weight adjustment part 11 and makes a specific signal 0 for every reception time was performed. The timing for setting this to 0 is based on the multiple reflection ultrasonic signal acquired when the ultrasonic wave is test-transmitted with various patterns (transmission numerical aperture, focus position) in a situation where the subject is not set in advance. A correction pattern set in consideration of the thickness was created and stored in the memory 008 shown in FIG.

  Each received signal that has been corrected (weight adjusted) is summed in the adder 12 and then adjusted so that the output value (gain change) that has been changed by the correction by the gain corrector 15 becomes equal when correction is not performed. That is, when the signal for 10 elements is set to 0 in the element weight adjusting unit 11, the gain adjustment is performed by 32 / (32-10) = 1.45 times. Then, it is sent to the Hilbert transformer 13 and the quadrature detector 14.

  The above system was actually used, and the case where both processes of the element weight adjustment unit 11 and the gain adjustment unit 15 were used was compared with the case where both processes were not performed. In addition, the measurement used the wire target of the ultrasonic phantom generally used for image confirmation with an ultrasonic image diagnostic apparatus. As a correction pattern, a pattern for setting the signal level to 0 for 10 elements in the central portion of the opening for 1 μsec was set (FIG. 9B). Further, the gain adjustment unit performed 1.45 times gain adjustment. FIG. 8A shows an image that has not been corrected (weight adjustment), and FIG. 8B shows an image that has been corrected (weight adjustment).

  First, when no correction is performed, the multiple reflections of the holding member 1 are clearly displayed as horizontal stripes. On the other hand, when the correction was performed, the multiple reflection component could be reduced to an almost inconspicuous level.

  Although the case where the correction pattern is fixed is shown in the first embodiment, the case where the correction pattern is changed in accordance with the change in the coordinates of the probe 2 will be described with reference to FIG.

  The second embodiment is different from the first embodiment in that the probe 2 can be moved (scanned) to an arbitrary position and a correction pattern is selected corresponding to the position of the probe 2.

The movable system unit 16 serving as a scanning means is installed in such a manner that a stepping motor and a ball screw are combined so that the probe 2 can be driven in the horizontal direction (the depth direction on the paper surface) along the surface of the holding member. The drive system may be anything that can adjust the amount of movement of a linear motor or the like.
A probe position information detection unit 17, which is detection means for detecting the position of the piezoelectric element 3 that is a vibrator, detects the position of the probe 2. In the present embodiment, a computer is used that sets the origin position of the probe 2 using a contact sensor, obtains the number of drive of the stepping motor, and calculates the amount of displacement from the origin.

  Depending on the position of the probe 2, the memory 8 has different acoustic characteristics of the holding member 1, structural characteristics such as thickness and deflection, and the reception status of the multiple reflection ultrasonic waves changes based on this. To cope with this, a plurality of correction patterns are recorded. In this embodiment, the inside of the holding member 1 is divided into 16 areas, and correction patterns are created and recorded in the memory 8 based on the multiple reflection ultrasonic patterns represented in each area. In this embodiment, there are 16 patterns, but if the memory 8 has a sufficient capacity, it is more effective to set it more finely. In the selection unit 18, a correction pattern corresponding to the position information of the probe 2 is called from the memory 8 and applied to each correction pattern in the element weight adjustment unit 11.

  When the correction pattern is fixed, unevenness due to multiple reflection may remain depending on the position of the probe 2. On the other hand, when the correction pattern was changed as in this example, it was confirmed that even when the position of the probe 2 was changed, the unevenness of multiple reflection could be further reduced.

  This embodiment will be described with reference to FIG.

(Device configuration)
The subject information acquisition apparatus according to the present embodiment is an example in which ultrasound is transmitted to and received from a subject without the holding member 1 (without the holding member 1 interposed).

(Device operation)
In the present embodiment, the ultrasonic wave transmitted (propagated) from the piezoelectric element 3 reaches the subject 9 after passing through a plurality of layers such as a matching layer and an acoustic lens without the holding member interposed. In this case, the reception signal by the multiple reflection ultrasonic waves in each layer such as the matching layer and the acoustic lens is superimposed on the image although it is slight. In this embodiment, when ultrasonic waves are transmitted in a test pattern with various patterns (transmission aperture, focus position), multiple reflected ultrasonic signals from a matching layer or acoustic lens, which is a member having an acoustic impedance different from that of the subject, are used. A correction pattern set based on the above was created. Specifically, as in Example 1, it was confirmed that there is a tendency to receive multi-reflection ultrasound at a relatively shallow position (at a time point shorter in time) than at the time of ultrasonic transmission / reception via the holding member. As in Example 1, the correction of FIG. 9B was applied for 0.5 μs. Since the reception pattern of multiple reflection differs depending on the type of the probe 2, the shape of the acoustic lens, and the transmission pattern, the correction pattern (X pattern) in FIG. 9A is not limited to the correction pattern in FIG. 9B. It is also effective to use (K pattern).

  Also in this example, it was confirmed that when the correction by the element weight adjustment unit 11 was performed, the multiple reflection component superimposed on the image was reduced as compared with the case where the correction was not performed.

  In the above-described embodiment, correction was performed using the correction pattern shown in FIG. 9B. However, the multiple reflection reception pattern differs depending on the type of the probe 2, the shape of the acoustic lens, and the transmission pattern. It is also effective to use the correction pattern 9 (a) (X pattern or K pattern).

DESCRIPTION OF SYMBOLS 1 Holding member 2 Probe 3 Piezoelectric element 4 Transmission processing part 5 Beam forming part 6 Image processing part 7 Image display part 8 Memory 11 Element weight adjustment part 16 Movable system 17 Probe position information detection part

Claims (11)

A plurality of transducers that transmit ultrasonic waves to a subject, receive reflected ultrasonic waves reflected by the subject, and output reception signals;
Control means for controlling the drive of the vibrator;
Signal adjusting means for correcting the received signal received by each transducer;
Have
The signal adjusting means is based on at least one of a drive pattern of the plurality of vibrators, a positional relationship between the plurality of vibrators, and a shape of a member provided between the subject and the vibrator. An object information acquiring apparatus, wherein a gain for the received signal is set so as to reduce a multiple reflection component included in the reflected ultrasound to be determined.   The object information acquiring apparatus according to claim 1, wherein the shape of the member is a thickness of the member.   The object information acquiring apparatus according to claim 1, wherein the driving pattern is a pattern for simultaneously driving the plurality of vibrators.   3. The drive pattern according to claim 1, wherein the drive pattern is a pattern that drives the plurality of transducers at different timings so that the transmitted ultrasonic waves converge within the subject. Subject information acquisition apparatus.   The object information acquisition apparatus according to claim 1, wherein the positional relationship between the plurality of transducers is an interval between adjacent transducers.   The object information acquiring apparatus according to claim 1, wherein the positional relationship between the plurality of transducers is the number of transducers that output the reception signal.   The object information acquiring apparatus according to claim 1, wherein the member is a holding member that holds the object.   The object information acquiring apparatus according to claim 1, wherein the member is an acoustic lens.   The object information acquiring apparatus according to claim 7, wherein the holding member transmits light.   The object information acquisition according to claim 7, further comprising: a scanning unit that scans the plurality of transducers along the surface of the holding member; and a detection unit that detects a position of the transducer. apparatus. An information acquisition method for acquiring information on a subject,
With a member having an acoustic impedance different from that of the subject interposed between the plurality of transducers and the subject, the plurality of transducers are driven to transmit ultrasonic waves to the subject, and the subject Receiving the reflected ultrasound reflected by the specimen with the plurality of transducers to obtain a received signal;
Correcting the acquired received signal;
Have
In the correcting step, a multiple reflection component included in the reflected ultrasonic wave determined based on at least one of a driving pattern of the plurality of transducers, a positional relationship between the plurality of transducers, and a shape of the member. A method for acquiring subject information, comprising the step of setting a gain for the received signal so as to reduce the received signal.