JP2014068756A - Ultrasonic inspection apparatus, ultrasonic image data generation method and program - Google Patents

Abstract

Even in a region where it is difficult to converge the focus, the S / N ratio can be increased, the resolution can be increased, and a high-resolution ultrasonic image can be obtained at a frame rate that is not different from the conventional one. An ultrasonic inspection apparatus is provided.
A focus resetting unit 98 that determines whether or not a transmission focus set by a focus setting unit 96 is within a predetermined range and resets the transmission focus within the predetermined range to a different position; The second element data corresponding to the first element data obtained by transmitting the ultrasonic beam from the first element data obtained by the transmission of the ultrasonic beam to the transmission focus reset by the focus resetting unit 98. And an element data processing unit 22 for generating the element data.
[Selection] Figure 1

Description

  The present invention relates to an ultrasonic inspection apparatus that performs imaging of an inspection target such as an organ in a living body by transmitting and receiving an ultrasonic beam, and generates an ultrasonic image used for inspection and diagnosis of the inspection target. The present invention relates to an ultrasonic image data generation method and program.

  Conventionally, in the medical field, an ultrasonic inspection apparatus such as an ultrasonic diagnostic imaging apparatus using an ultrasonic image has been put into practical use. In general, this type of ultrasonic inspection apparatus has an ultrasonic probe (ultrasonic probe) including a plurality of elements (ultrasonic transducers), and an apparatus main body connected to the ultrasonic probe. The ultrasonic probe transmits the ultrasonic beam from the multiple elements of the ultrasonic probe toward the inspection object (subject), receives the ultrasonic echo from the subject, and receives the ultrasonic echo. An ultrasonic image is generated by electrically processing the ultrasonic echo signal thus processed in the apparatus main body.

  In an ultrasonic inspection apparatus, when generating an ultrasonic image, an ultrasonic wave is focused on a region to be inspected of a subject, for example, an organ in a living body or a lesion in the organ from a plurality of elements of the probe. Transmits a beam and receives ultrasonic echoes from the surface or interface of a reflector in the examination target area, for example, an organ or a lesion, via multiple elements, but is reflected by the same reflector. Are reflected by the reflector located at the focal position of the ultrasonic beam transmitted from the transmitting element, and reflected by the same reflector with respect to the ultrasonic echo signal received by the transmitting element. Since the ultrasonic echo signals received by other elements different from the transmitting element are delayed, the ultrasonic echo signals received by a plurality of elements are A / D (analog / digital) converted into element data. And after Data reception focusing processing, and generates an ultrasound image based on the generated sound ray signals by phasing and adding the combined phase, thus obtained sound ray signal or delay correction to.

In such an ultrasonic inspection technique, in order to improve the image quality of an ultrasonic image, the signal quality is improved compared to the conventional technique by adding together signals transmitted at a plurality of different focal points.
For example, in Patent Document 1, a virtual point sound source is formed by focusing transmission ultrasonic waves radiated from a plurality of vibration elements constituting a transmission vibration element group on a transmission focusing point. Received ultrasonic waves reflected from a plurality of continuous observation points by transmitted ultrasonic waves radiated from a sound source are received by a plurality of vibration elements constituting a reception vibration element group, and the received signals for the obtained channels are received. Receive phasing and addition is performed so that the observation point becomes the reception focus point. Further, similar reception phasing addition is performed on the reception signal obtained using each of the reception vibration element group and the transmission vibration element group sequentially shifted in the arrangement direction of the vibration elements. There has been disclosed an ultrasonic diagnostic apparatus that performs transmission phasing addition for correcting a transmission delay caused by a difference in propagation distance from each transmission focusing point to an observation point with respect to a reception signal after phase addition.
In Patent Document 1, the reception phasing addition and the transmission phasing addition are performed on reception signals obtained from a plurality of vibration elements, thereby having a substantially uniform thin beam width in the depth direction of the subject. The transmission beam and the reception beam can be formed with high accuracy and high sensitivity. For this reason, Patent Document 3 discloses that image data can be generated and displayed with excellent spatial resolution, contrast resolution, and S / N.

JP 2009-240700 A

However, with the technique disclosed in Patent Document 1, an image with higher image quality than that of the conventional technique can be obtained. However, in order to create one line of data, it is necessary to generate a plurality of transmission beams by changing transmission positions. Since the number of transmissions is higher than that of the technology, there is a problem that the frame rate is lowered and the real-time property is deteriorated. In Patent Document 1, the focal point is regarded as a virtual point sound source, but in reality, the focal point is not converged to the extent that it can be regarded as a point sound source, and the SN ratio and resolution decrease as the image is closer to the focal point. There was a problem.
Also, usually, when acquiring an ultrasound image, it is possible to generate an ultrasound image with good image quality in the region of interest by setting the focal point in the vicinity of the region of interest and transmitting and receiving ultrasound. it can. However, in principle, it is difficult to focus the ultrasonic beam on the surface layer or the deep layer, and when focusing on the surface layer or the deep layer, it is difficult to improve the image quality of the surface layer or the deep layer.

  An object of the present invention is to solve the above-mentioned problems of the prior art, increase the SN ratio and increase the resolution even in a region where it is difficult to converge the focus, and a frame rate that is the same as the conventional frame rate. It is still another object of the present invention to provide an ultrasonic inspection apparatus, an ultrasonic image data generation method, and a program capable of obtaining a sharp ultrasonic image having an optimum spatial resolution with high resolution.

  In order to achieve the above object, the present invention is an ultrasonic diagnostic apparatus for inspecting an inspection object using an ultrasonic beam, wherein the ultrasonic wave is transmitted and reflected by the inspection object. A probe in which a plurality of elements are arranged to receive an echo and output an analog element signal corresponding to the received ultrasonic echo, and a focus setting unit that sets a plurality of transmission focal points in the inspection object A focus resetting unit that determines whether or not the position of the transmission focus set by the focus setting unit is within a predetermined range, and resets the position of the transmission focus within the predetermined range to a different position; For each of the transmission focal point determined to be out of the predetermined range by the setting unit and the reset transmission focal point, the probe uses a plurality of the elements, and transmits the ultrasonic beam. Individual ultrasound beams for each focus In response to the transmission of a digital signal, a digital element signal is obtained by A / D-converting a receiving unit that receives analog element signals output from a plurality of elements and performs predetermined processing, and an analog element signal processed by the receiving unit. Obtained by transmitting an ultrasonic beam to the transmission focus reset by the focus resetting unit from the AD conversion unit as the first element data and the first element data obtained by transmitting a plurality of ultrasonic beams An ultrasonic inspection apparatus comprising: an element data processing unit that generates second element data corresponding to the obtained first element data.

Here, it is preferable that the focus resetting unit resets the transmission focus to a depth different from the transmission focus set by the focus setting unit.
Moreover, it is preferable that the focus resetting unit resets the transmission focus at a different position on the same line as the line for transmitting the ultrasonic beam with respect to the transmission focus set by the focus setting unit.

The focus resetting unit resets the position of the transmission focus to a position deeper than the position set by the focus setting unit when the depth of the transmission focus set by the focus setting unit is shallower than a predetermined depth. It is preferable to set.
The focus resetting unit resets the position of the transmission focus to a position shallower than the position set by the focus setting unit when the depth of the transmission focus set by the focus setting unit is deeper than a predetermined depth. It is preferable to set.

In addition, it is preferable that the transmission unit causes the probe to use a plurality of elements and transmits an ultrasonic beam to each transmission focal point by changing a central element.
Moreover, it is preferable that the element data processing unit uses first element data obtained by transmitting a plurality of ultrasonic beams having different central elements.
Moreover, it is preferable that the element data processing unit uses first element data obtained by transmitting a plurality of ultrasonic beams in which the transmission areas of the ultrasonic beams overlap.

The element data processing unit superimposes a plurality of first element data according to the reception time when the element receives the ultrasonic echo and the position of the element, and second element data corresponding to the first element data Is preferably generated.
In addition, the element data processing unit synthesizes a plurality of first element data obtained by transmitting the ultrasonic beam with the elements that are continuous in the element arrangement direction as the center elements, and generates second element data. Is preferably generated.
The element data processing unit transmits a plurality of ultrasonic beams obtained by transmitting the ultrasonic beam using the same number of elements adjacent to the central element corresponding to the ultrasonic beam whose transmission focus is reset as the central element. It is preferable to combine the first element data to generate the second element data.

In addition, the element data processing unit includes a delay time calculation unit that calculates a delay time of two or more first element data, a delay time calculated from two or more first element data, and a received probe. It is preferable to have a superimposition processing unit that superimposes based on the position of the element and generates second element data.
Further, the delay time calculation unit includes a probe acquired in advance, the sound speed of the inspection object, the position of the transmission focal point of the ultrasonic beam, the transmission opening of the probe by the transmission unit, and the probe of the probe by the reception unit. The delay time of two or more first element data is calculated based on at least one piece of information about the reception aperture, and the overlay processing unit superimposes among the preset two or more first element data. It is preferable to generate the second element data by superimposing two or more pieces of the first element data based on the number of element data of one and the overlay processing method.
The element data processing unit preferably superimposes two or more pieces of first element data after multiplying each of the first element data by a weighting coefficient.
In addition, it is preferable that the transmission unit causes the probe to transmit the ultrasonic beam to the transmission focal point before resetting determined to be within a predetermined range by the focus resetting unit.
Moreover, it is preferable to have an element data holding part which hold | maintains all the 1st element data which the receiving part output.

  In order to achieve the above object, the present invention generates a plurality of components of an ultrasonic beam, receives ultrasonic echoes reflected in an inspection object, and outputs received analog signals. An ultrasonic image data generation method for generating an ultrasonic image data by generating an ultrasonic beam by using a probe including the element, and generating ultrasonic image data. It is determined whether the focus setting step for setting the focus and the position of the transmission focus set by the focus setting step are within a predetermined range, and reset the position of the transmission focus within the predetermined range to a different position. For each of the focus resetting step, the transmission focus determined to be out of a predetermined range by the focus resetting unit, and the reset transmission focus, a plurality of elements are used in the probe, Send beam In response to transmission of individual ultrasonic beams for each transmission focus, a reception step for receiving analog element signals output by a plurality of elements and performing predetermined processing, and an analog element signal processed by the reception step A / D conversion is performed in the focus resetting step from the AD converting step to obtain the first element data which is a digital element signal and the first element data obtained by transmitting a plurality of ultrasonic beams. And an element data processing step for generating second element data corresponding to the first element data obtained by transmitting the ultrasonic beam to the transmission focal point. provide.

  In order to achieve the above object, the present invention generates a plurality of components of an ultrasonic beam, receives ultrasonic echoes reflected in an inspection object, and outputs received analog signals. An ultrasonic image data generation program for causing a computer to generate an ultrasonic beam by a probe including the element, inspect an inspection object, and generate ultrasonic image data. A focus setting step for setting a predetermined transmission focus, and whether or not the position of the transmission focus set by the focus setting step is within a predetermined range, and determines the position of the transmission focus within the predetermined range. A focus resetting step for resetting to a different position, a plurality of transmission focal points determined to be out of a predetermined range by the focus resetting unit, and a reset transmission focal point for each of a plurality of probes. A transmitting step for transmitting an ultrasonic beam using a child, and a receiving step for receiving analog element signals output from a plurality of elements in response to transmission of individual ultrasonic beams for the respective transmission focal points and performing predetermined processing; The analog element signal processed in the reception step is A / D converted to be first element data which is a digital element signal, and first element data obtained by transmitting a plurality of ultrasonic beams And an element data processing step for generating second element data corresponding to the first element data obtained by transmitting the ultrasonic beam to the transmission focal point reset in the focus resetting step. An ultrasonic image data generation program is provided.

  According to the present invention, when the set focal position is within a predetermined range, the focal position is reset, and the second element data is generated by synthesizing two or more different first element data. Even in areas where it is difficult to focus the focus of the ultrasonic beam, such as the surface layer or deep layer, the SN ratio can be increased, the resolution can be increased, and the frame rate remains the same as before, with a high resolution. A sharp ultrasonic image with optimum spatial resolution can be obtained.

It is a block diagram which shows notionally an example of a structure of the ultrasonic inspection apparatus which concerns on this invention. (A)-(C) are the conceptual diagrams for demonstrating reset of a focus position. It is a block diagram which shows notionally an example of a structure of the element data processing part of the ultrasonic inspection apparatus shown in FIG. (A) And (c) is explanatory drawing in the case of transmitting an ideal ultrasonic beam from the element right above the reflective point of a subject, and the element not right above, respectively, (b) and (d) FIG. 5 is an explanatory diagram showing element data obtained respectively. (A) And (c) is explanatory drawing in the case of transmitting an actual ultrasonic beam from the element directly above the reflection point of the subject and the element not directly above, respectively, (b) and (d) It is explanatory drawing which shows the element data obtained, respectively. (A) And (b) is explanatory drawing explaining the distance of the transmission path | route and reception path | route of an ultrasonic beam in the case of the reflected signal of a true reflected ultrasonic echo and a ghost, respectively (c) and (d) These are explanatory drawings showing element data obtained by a plurality of elements and their delay times. (A), (b) and (c) and (d), (e) and (f) are respectively the element data obtained by a plurality of elements in the case of a true signal and the case of a ghost, their delay time and It is explanatory drawing which shows the superimposition state of element data, (g) And (h) is explanatory drawing which shows the superimposition state of the element data corresponding to a some element, respectively, and its result. 3 is a flowchart for explaining the operation of the ultrasonic inspection apparatus shown in FIG. 1. (A) And (B) is a flowchart for demonstrating operation | movement of another example of the ultrasonic inspection apparatus which concerns on this invention.

  The ultrasonic inspection apparatus, ultrasonic image data generation method and program according to the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a block diagram conceptually showing an embodiment of the configuration of the ultrasonic inspection apparatus of the present invention.
As shown in FIG. 1, the ultrasonic inspection apparatus 10 includes an ultrasonic probe 12, a transmission unit 14 and a reception unit 16 connected to the ultrasonic probe 12, an A / D conversion unit 18, and an element data storage unit 20. The element data processing unit 22, the image generation unit 24, the display control unit 26, the display unit 28, the control unit 30, the operation unit 32, the storage unit 34, the focus setting unit 96, and the focus resetting. Part 98.

The ultrasonic probe (ultrasonic probe) 12 has a transducer array 36 used in a normal ultrasonic inspection apparatus.
The transducer array 36 includes a plurality of elements arranged in a one-dimensional or two-dimensional array, that is, ultrasonic transducers. These ultrasonic transducers transmit an ultrasonic beam to a subject in accordance with a drive signal supplied from the transmission unit 14 when an ultrasonic image of an object to be examined (hereinafter referred to as a subject) is captured. An ultrasonic echo from the specimen is received and a reception signal (analog element signal) is output. In the present embodiment, each of the predetermined number of ultrasonic transducers forming one set among the plurality of ultrasonic transducers of the transducer array 36 generates each component of one ultrasonic beam, and sets a predetermined number of ultrasonic transducers. The ultrasonic transducer generates one ultrasonic beam that is transmitted to the subject.

  Each ultrasonic transducer includes, for example, a piezoelectric ceramic represented by PZT (lead zirconate titanate), a polymer piezoelectric element represented by PVDF (polyvinylidene fluoride), PMN-PT (magnesium niobate / lead titanate). It is constituted by an element in which electrodes are formed at both ends of a piezoelectric body made of a piezoelectric single crystal or the like typified by a solid solution, that is, a vibrator.

  When a pulsed or continuous wave voltage is applied to the electrodes of such a vibrator, the piezoelectric material expands and contracts, and pulse or continuous wave ultrasonic waves are generated from the respective vibrators, and the synthesis of these ultrasonic waves. As a result, an ultrasonic beam is formed. In addition, each vibrator expands and contracts by receiving propagating ultrasonic waves to generate electric signals, and these electric signals are output as ultrasonic reception signals (analog element signals).

The focus setting unit 96 transmits a plurality of transmission lines and each transmission when the transducer array 36 transmits an ultrasonic beam according to transmission focus information (focus position information) input from the operation unit 32. Set the focal position on the line.
Specifically, like the conventional ultrasonic inspection apparatus, the focus setting unit 96 sets the display area (inspection range), the depth (depth), and the like input from the operation unit 32, and the transducer array 36. A plurality of transmission lines that transmit ultrasonic beams are set according to the arrangement interval of the transducers, and the position that becomes the focal point of the ultrasonic beams is automatically set on each transmission line.
Note that the focus setting unit 96 may set the focus position from the focus position information directly input by the operator from the operation unit 32.

2A to 2C show an example of the set focal position.
In the example shown in FIGS. 2A to 2C, one transmission line is set on the same line as each element corresponding to each element (ultrasonic transducer) of the transducer array 36. In addition, one focal position is set at the same depth on each transmission line.
Information on the set focus position is supplied to the focus resetting unit 98.

The focus resetting unit 98 determines whether or not each focus position set by the focus setting unit 96 is within a predetermined depth range. If the focus position is within the predetermined range, the focus position is set to a different depth. Reset it.
Specifically, the focus resetting unit 98 is positioned deeper than the position set by the focus setting unit 96 when the focus position set by the focus setting unit 96 is shallower than the predetermined depth Za. If the focus position set by the focus setting unit 96 is deeper than the predetermined depth Zb, the focus position is set to a position shallower than the position set by the focus setting unit 96. Reset it. The focus resetting unit 98 resets the focus position when the focus position set by the focus setting unit 96 is not within the predetermined range, that is, when the focus position is at a depth between Za and Zb. The position set by the focus setting unit 96 is set as the focus position without setting.

The resetting of the focus position will be described in more detail with reference to FIGS.
As shown in FIG. 2A, when the focus position set by the focus setting unit 96 is at a position shallower than the predetermined depth Za, each focus position is set on the same transmission line. A deep position is reset to a position deeper than Zb in the illustrated example.
As shown in FIG. 2B, when the focus position set by the focus setting unit 96 is at a position deeper than the predetermined depth Zb, each focus position is set on the same transmission line. In the illustrated example, the position is reset to a position shallower than Za.
As shown in FIG. 2C, when the focus position set by the focus setting unit 96 is deeper than a predetermined depth Za and shallower than Zb (at a depth between Za and Zb). In the case), the focus position is not reset, and the position set by the focus setting unit 96 is set as the focus position.

Here, the predetermined depths Za and Zb for determining whether or not the focus resetting unit 98 resets the focal position are not particularly limited, but the predetermined depth Za is sufficient for the ultrasonic beam. It is preferable that the depth is shallower than the depth that can be converged to, for example, about 1 cm, and the predetermined depth Zb can sufficiently converge the ultrasonic beam when the transmission numerical aperture is maximum. It is preferable that the depth is deeper than the depth. That is, when the focal position is at a position where the ultrasonic beam can be sufficiently converged (between Za and Zb), the focal position is not reset and the ultrasonic beam is sufficiently converged. If it is at a position where no focus is possible, it is preferable to reset the focus position.
Whether or not the convergence degree of the ultrasonic beam is sufficient may be determined according to the performance of the ultrasonic probe, the required SN ratio, resolution, and the like.

Further, the depth of focus when the focus resetting unit 98 resets the focus position is not particularly limited, but the focus position set by the focus setting unit 96 is shallower than the predetermined depth Za. In this case, it is preferable to reset to a position deeper than the predetermined depth Za, and it is more preferable to reset to a position as deep as possible within the range where the focus can be achieved. Similarly, when the focus position set by the focus setting unit 96 is deeper than the predetermined depth Zb, it is preferable to reset to a position shallower than the predetermined depth Zb, and as much as possible within the range where the focus can be achieved. It is more preferable to reset to a shallow position.
The focus resetting unit 98 supplies information on the reset focus position to the transmission unit 14 and the control unit 30.

The transmission unit 14 includes, for example, a plurality of pulsers, and based on the transmission delay pattern selected according to the control signal from the control unit 30 and the focus position information from the focus resetting unit 98, the transducer array An ultrasonic beam component transmitted from a set of a predetermined number of ultrasonic transducers (hereinafter referred to as ultrasonic elements) forms one ultrasonic beam and forms a focal point at the set / reset focal position. As described above, the delay amount of each drive signal is adjusted and supplied to a plurality of ultrasonic elements forming a set.
Specifically, the transmission unit 14 uses an ultrasonic element on the same line as the set transmission line as a central element, and the central element and a plurality of adjacent ultrasonic elements are combined into a set of transmission elements (transmission apertures). ), A drive signal is supplied so as to transmit an ultrasonic beam that forms a focal point at the set / reset focal position.

Here, the transmission unit 14 has at least the transmission focus determined to be outside the predetermined range by the focus resetting unit 98 and the transmission focus determined to be within the predetermined range by the focus resetting unit 98 and reset. Thus, it is preferable to supply a drive signal to the transducer array 36 so as to transmit an ultrasonic beam.
The transmission unit 14 may transmit the ultrasonic beam to the transmission focal point before resetting, which is determined by the focus resetting unit 98 to be outside the predetermined range.

In response to a control signal from the control unit 30, the receiving unit 16 causes the transducer array 36 to transmit the ultrasonic echo generated by the interaction between the ultrasonic beam transmitted from the transducer array 36 and the subject. Received and output received signals, ie, analog element signals for each ultrasonic element are amplified and output.
Specifically, the receiving unit 16 uses the central element when the corresponding ultrasonic beam is transmitted and a plurality of ultrasonic elements adjacent to the central element as a set of receiving elements (reception apertures). The ultrasonic echoes reflected within are received.

Here, the reception unit 16 includes a plurality of analog element signals received by a plurality of ultrasonic elements, corresponding to one transmission of the ultrasonic beam, and includes information on the received ultrasonic elements and information on reception times. One analog element data (first element data) is output. That is, the element data (first element data) is data representing the intensity of the received signal with respect to the position of the element and the reception time (see FIG. 4 and the like).
The receiving unit 16 receives an ultrasonic echo and outputs analog element data every time the transmitting unit 14 transmits one ultrasonic beam. Therefore, the transmission unit 14 outputs a plurality of analog element data corresponding to each transmission by transmitting the ultrasonic beam a plurality of times in accordance with the set transmission line.
The receiver 16 supplies analog element data to the A / D converter 18.

  The A / D conversion unit 18 is connected to the reception unit 16 and converts the analog element data supplied from the reception unit 16 into digital element data (first element data). The A / D converter 18 supplies the A / D converted digital element data to the element data storage unit 20.

The element data storage unit 20 sequentially stores digital element data output from the A / D conversion unit 18. In addition, the element data storage unit 20 stores information on the frame rate input from the control unit 30 (for example, parameters indicating the depth of the reflection position of the ultrasonic wave, the density of the scanning line, and the visual field width) in the digital element data ( Hereinafter, the data is stored in association with element data).
When the focus position is reset by the focus resetting unit 98 based on the control by the control unit 30, the element data storage unit 20 is obtained by transmitting and receiving an ultrasonic beam through the transmission line whose focus position is reset. The stored element data and two or more element data obtained by transmitting the ultrasonic beam to different transmission lines are stored and held.

The element data processing unit 22 is obtained by transmitting an ultrasonic beam to the transmission line whose focus position is reset when the focus position is reset by the focus resetting unit 98 based on the control by the control unit 30. In response to the received element data, the element data and two or more element data corresponding to transmission lines different from the element data (hereinafter also referred to as unprocessed element data) are read from the element data storage unit 20 and received. Based on the time information and the information on the geometrical arrangement of the ultrasonic elements, the time and position are corrected and overlapped, and the superimposed element data (second element data, hereinafter referred to as processed element data). ) Is generated.
The element data processing unit 22 supplies the processed element data to the image generation unit 24 (phasing addition unit 38).

  As described above, normally, when acquiring an ultrasound image, an ultrasound image having a good image quality in the region of interest is generated by setting the focus in the vicinity of the region of interest and transmitting and receiving ultrasound. However, it is difficult in principle to focus the ultrasonic beam on the focal point at a shallow position (surface layer) or a deep position (deep layer). Therefore, when paying attention to the surface layer and the deep layer, it is difficult to improve the image quality of the surface layer and the deep layer.

On the other hand, the present invention resets the focal position to a deeper position when the focal position of the ultrasonic beam is on the surface layer, and focuses on a shallower position when it is in the deep layer. Resetting the position, transmitting and receiving ultrasound, and combining the obtained multiple element data based on the element's geometrical arrangement and reception time information to generate new element data This makes it possible to increase the signal-to-noise ratio and increase the resolution even at the surface layer and deep layer where it is difficult to converge the focus, and achieve the optimum spatial resolution at a high resolution with the same frame rate as before. A sharp ultrasonic image can be obtained.
Details of the element data processing unit 22 will be described later.

  Note that the element data processing unit 22 may generate unprocessed element data by superimposing the unprocessed element data even when the focus position is not reset, or may superimpose the unprocessed element data. You may supply unprocessed element data to the image generation part 24 as processed element data, without performing a matching process.

The image generation unit 24 generates a sound ray signal (reception data) from the processed element data supplied from the element data processing unit 22 under the control of the control unit 30, and generates an ultrasonic image from the sound ray signal. Is.
The image generation unit 24 includes a phasing addition unit 38, a detection processing unit 40, a DSC 42, an image creation unit 44, and an image memory 46.

The phasing addition unit 38 selects one reception delay pattern from a plurality of reception delay patterns stored in advance according to the reception direction set in the control unit 30, and based on the selected reception delay pattern Thus, the reception focus processing is performed by adding the respective delays to the signal of each element of the element data. By this reception focus processing, reception data (sound ray signal) in which the focus of the ultrasonic echo is narrowed is generated.
The phasing addition unit 38 supplies the received data to the detection processing unit 40.

The detection processing unit 40 corrects attenuation by distance according to the depth of the reflection position of the ultrasonic wave on the reception data generated by the phasing addition unit 38, and then performs envelope detection processing to perform detection. B-mode image data that is tomographic image information related to the tissue in the specimen is generated.
A DSC (digital scan converter) 48 converts (raster conversion) the B-mode image data generated by the detection processing unit 40 into image data according to a normal television signal scanning method.

The image creation unit 44 performs various necessary image processing such as gradation processing on the B-mode image data input from the DSC 42 to create B-mode image data for use in inspection and display, and then creates the created inspection. Or display B-mode image data is output to the display control unit 26 for display or stored in the image memory 46.
The image memory 46 temporarily stores the inspection B-mode image data created by the image creation unit 44. The inspection B-mode image data stored in the image memory 46 is read to the display control unit 26 for display on the display unit 28 as necessary.

The display control unit 26 causes the display unit 28 to display an ultrasonic image based on the inspection B-mode image signal subjected to the image processing by the image creation unit 44.
The display unit 28 includes a display device such as an LCD, for example, and displays an ultrasonic image under the control of the display control unit 26.

The control unit 30 controls each unit of the ultrasonic inspection apparatus 10 based on a command input from the operation unit 32 by the operator.
Here, the control unit 30 provides various information by the operator via the operation unit 32, particularly information necessary for setting the focus by the focus setting unit 96 and the focus resetting unit 98, and an element data processing unit. When the information necessary for processing the element data is input at 22, the above-described various information input from the operation unit 32 is transmitted as necessary to the transmission unit 14, the reception unit 16, and the element data. The data is supplied to each unit such as the storage unit 20, the element data processing unit 22, the image generation unit 24, the display control unit 26, the focus setting unit 96, and the focus resetting unit 98.

The operation unit 32 is for an operator to perform an input operation, and can be formed from a keyboard, a mouse, a trackball, a touch panel, and the like.
In addition, the operation unit 32 provides various information as required by the operator, particularly information on the display area (examination range), depth (depth), transducer array 36, focus position, and the like used for setting the above-described focus position. And information regarding the sound speed of the examination region of the subject used for element data processing, information regarding the transmission aperture and reception aperture of the transducer array 36, and information regarding element data processing such as the number of overlapping element data and the overlapping processing method Etc. are provided for input operation.

The storage unit 34 receives various information input from the operation unit 32, in particular, information related to the display area, depth, probe 12 (vibrator array 36), sound speed, focal position, transmission aperture, reception aperture, and the like. Information related to element data processing such as the number of element data and overlay processing method, etc., and control of the transmission unit 14, the reception unit 16, the element data storage unit 20, the element data processing unit 22, the image generation unit 24, the display control unit 26, etc. Stores information necessary for processing and operation of each unit controlled by the unit 30 and operation programs and processing programs for executing the processing and operation of each unit. Hard disk, flexible disk, MO, MT, RAM Recording media such as CD-ROM and DVD-ROM can be used.
The element data processing unit 22, the phasing addition unit 38, the detection processing unit 40, the DSC 42, the image creation unit 44, the focus setting unit 96, the focus resetting unit 98, and the display control unit 26 include a CPU and various types of CPUs. The program is composed of operation programs for performing processing, but may be configured by a digital circuit.

Here, the element data processing unit 22 will be described in detail with reference to FIG.
As shown in the figure, the element data processing unit 22 includes a delay time calculation unit 48 and an overlay processing unit 50.
The delay time calculation unit 48 examines the plurality of ultrasonic elements and the subject of the transducer array 36 of the probe 12 input from the operation unit 32 or input from the operation unit 32 and stored in the storage unit 34. Information regarding the sound velocity of the target region, information on the transmission aperture and reception aperture of the transducer array 36, and the focus position reset by the focus resetting unit 98 are acquired in advance, and an ultrasonic beam is formed and transmitted. Based on the geometric arrangement of the ultrasonic element (transmitting element) of the opening and the ultrasonic element (receiving element) of the receiving opening that receives an ultrasonic echo from the subject by the ultrasonic beam, The delay time of the element data received by each ultrasonic element is calculated.

The overlay processing unit 50 relates to element data processing such as the number of element data to be superimposed and the overlay processing method, which are input from the operation unit 32 or input from the operation unit 32 and stored in the storage unit 34. Based on the information, two or more pieces of element data obtained by transmitting ultrasonic beams to different transmission lines stored and held by the element data storage unit 20 are read out, and a predetermined line to be subjected to overlay processing is determined. Focusing on this point (sampling point), two or more unprocessed element data are received on the reception time, that is, timed and received based on the delay times calculated by the delay time calculation unit 48 respectively. The processed element data is generated by superposing and aligning the absolute positions of the elements of the probe.
By paying attention to a predetermined sampling point and superimposing a plurality of unprocessed element data, element data that focuses on this sampling point can be obtained.

The processed element data generated by superimposing unprocessed element data using at least one point of the target line as a sampling point may be used as the element data of the target line, and the target line is divided into a plurality of regions. Then, sampling points may be set in each area, and processed element data may be generated by superimposing unprocessed element data, and may be used as element data in each area of the target line. Alternatively, the processed element data may be generated by using all pixel positions as sampling points corresponding to the pixel positions when the ultrasonic image is generated.
In particular, it is preferable to set the sampling point at the position where the focus setting unit 96 has set the focus position, that is, the focus position before being reset. There is a high possibility that the position (depth) at which the focus setting unit 96 sets the focus position is a region that the operator is paying attention to or a region that the operator wants to see. Therefore, by setting a sampling point at the focus position set by the focus setting unit 96 and superimposing unprocessed element data, element data that is focused on the region that the operator is interested in to obtain is obtained. be able to.

Next, element data processing performed by the element data processing unit 22 will be described in detail.
First, an ultrasonic beam (hereinafter simply referred to as a transmission beam) is transmitted to an object from an ultrasonic element (hereinafter simply referred to as a transmission element) forming a transmission aperture of the transducer array 36 of the ultrasonic probe 12, and between the objects. In the case where element data (unprocessed element data) is obtained by receiving an ultrasonic echo generated by the interaction of the ultrasonic echoes by an ultrasonic element (hereinafter simply referred to as a receiving element) that forms a receiving aperture of the transducer array 36, The relationship between the transmission beam from the element and element data obtained by the receiving element will be described.

4A and 4C, as an example, transmission lines are set corresponding to each ultrasonic element in a direction orthogonal to the arrangement direction of the ultrasonic elements, and one focal position is set for each transmission line. It is a figure which shows typically each ultrasonic element at the time of setting (re-setting), an ultrasonic beam, a focus position, and an ultrasonic echo.
As shown in FIGS. 4 (a) and (c), three ultrasonic elements 52c to 52e and 52d to 52f are used as transmitting elements, respectively, and seven ultrasonic elements (hereinafter also simply referred to as elements) 52a to 52g. And 52b to 52h as receiving elements, when receiving ultrasonic echoes and acquiring element data, the transmission beam 56 to be transmitted to the inspection target region including the reflection point 54 is ideally narrowed to an element interval or less. In this case, as shown in FIG. 4A, the elements 52c to 52e having the central element 52d of the elements 52a to 52g, which are directly above the reflection point 54 in the inspection target region, as transmission elements, When transmitting the transmission beam 56 to the transmission line corresponding to the element 52d and receiving the ultrasonic echoes by the receiving elements 52a to 52g to acquire element data, the focal point 58 of the transmission beam 56 is 4d and is in a straight line connecting the reflection point 54, the transmitted beam 56, since it is transmitted to the reflection point 54, the ultrasonic echoes are generated to be reflected from the reflection point 54. The ultrasonic echoes from the reflection point 54 are received by the receiving elements 52a to 52g through the receiving path 60 spreading to a predetermined angle, and the element data 62 as shown in FIG. 4B is obtained by the receiving elements 52a to 52g. Will be.

  On the other hand, as shown in FIG. 4C, when the center of the transmitting element is shifted by one element from the reflection point 54 in the element direction (right direction in the figure), that is, the reflection point 54. The element 52d to 52f having the element 52e adjacent to the element 52d immediately above the center element as a transmission element is used as a transmission element, the transmission beam 56 is transmitted to the transmission line corresponding to the element 52e, and the ultrasonic echo is received by the reception elements 52b to 52h , The reflection point 54 does not exist on the transmission direction of the transmission beam 56, that is, on the straight line connecting the transmission element 52 e and the focal point 58 (on the transmission line). Not sent. For this reason, the ultrasonic echo reflected from the reflection point 54 is not generated, and the receiving elements 52b to 52h do not receive the ultrasonic echo. Therefore, as shown in FIG. It becomes the data of.

However, as shown in FIGS. 5A and 5C, the actual transmission beam 64 is wider than the element spacing.
Here, as shown in FIG. 5A, the transmission beam 64 is transmitted to the transmission line corresponding to the element 52d, with the elements 52c to 52e having the element 52d immediately above the reflection point 54 as the central element as transmission elements. In this case, as in the case of FIG. 4A, even if the transmission beam 56 is wide, its focal point 58 is on a straight line connecting the element 54d and the reflection point 54, and the transmission beam 64 is reflected. Reflected at point 54, an ultrasonic echo is generated. As a result, as in the case of FIG. 4A, the ultrasonic echo from the reflection point 54 is received by the receiving elements 52a to 52g through the receiving path 60 spreading to a predetermined angle, and is received by the receiving elements 52a to 52g. True element data 66 as shown in FIG. 5B is obtained.

On the other hand, as shown in FIG. 5C, as in the case of FIG. 4C, the center of the transmitting element is shifted by one element from the reflection point 54 in the element direction (right direction in the figure). In other words, the transmission beam 64 is transmitted to the transmission line corresponding to the element 52e, with the elements 52d to 52f having the element 52e adjacent to the element 52d immediately above the reflection point 54 as a central element, as transmission elements. When receiving the ultrasonic echoes by the receiving elements 52b to 52h, the transmission beam 64 is wide, so that the reflection point 54 does not exist on the transmission direction, that is, on the straight line connecting the transmitting element 52e and the focal point 58. However, the transmission beam 64 is transmitted to the reflection point 54. For this reason, the ultrasonic echoes reflected from the reflection point 54 are received by the receiving elements 52b to 52h through the receiving path 60 spreading at a predetermined angle, and as shown in FIG. 5 (d) by the receiving elements 52b to 52h. Element data 68 affected by the reflection point is obtained.
When an acoustic ray signal is generated from element data 68 (hereinafter also referred to as ghost element data) affected by a reflection point other than on the transmission line, an ultrasonic image is generated, which corresponds to the element 52e. An image of a reflection point that does not actually exist is reproduced in the line image, so-called ghost is generated, and this causes a decrease in the accuracy of the ultrasonic image.

  Here, the transmission beam 64 shown in FIG. 5C is transmitted from the transmission element 52e via the focal point 58 to the reflection point 54, and the ultrasonic echo from the reflection point 54 is received to the reception elements 52b to 52h. The sum (propagation distance) with the path is such that the transmission beam 64 shown in FIG. 5A reaches the reflection point 54 from the transmission element 52 d via the focal point 58 and the reflected ultrasonic echo from the reflection point 54. It becomes longer than the sum (propagation distance) with the receiving path reaching each receiving element 52a to 52g. Therefore, the ghost element data 68 as shown in FIG. 5D is delayed with respect to the true element data 66 as shown in FIG. 5B.

  In the delay time calculation unit 48 of the element data processing unit 22 according to the present invention, the geometrical arrangement of the sampling point on the transmission line of interest and the central element corresponding to each transmission line causes a super Element data obtained by transmitting / receiving sound waves (hereinafter also referred to as “target element data”) and element data obtained by transmitting / receiving ultrasonic waves to a transmission line different from the target transmission line (hereinafter, “non-target element data”) ), That is, a delay time is calculated. Therefore, for calculating the delay time, the shape of the ultrasonic probe 12 (vibrator array 36) (element spacing, linear, convex, etc.), the sound velocity of the examination region of the subject, the focal position, the transmission aperture, the reception aperture, etc. Information is required, and the delay time calculation unit 48 acquires information on the focus position reset by the focus resetting unit 98 and the information input by the operation unit 32 or stored in the storage unit 34. To calculate the delay time. The delay time is calculated from, for example, the transmission path and sampling point of the transmission beam from the transmission element to the sampling point through the focal point, which is calculated from the geometry of the transmission element, the focus of the ultrasonic beam, the sampling point, and the reception element. It can be calculated from the difference between the total length (propagation distance) of the reception path of the reflected signal reaching the reception element and the propagation time calculated by the sound speed.

In the present invention, for example, as shown in FIGS. 6 (a) and 6 (b), the lengths of the transmission path of the transmission beam and the reception path of the ultrasonic echo of each of the target element data and the non-target element data are set. Can be sought. In FIG. 6A and FIG. 6B, for the sake of explanation, it is assumed that there is a reflection point 54 at the sampling point on the target transmission line.
As shown in FIG. 6A, in the case of element-of-interest data, that is, when the transmission line of interest coincides with the transmission line that transmitted the ultrasonic beam, the central elements of the transmission elements 52c to 52e, and the reception element The central elements 52a to 52g coincide with each other, and the focal point 58 and the reflection point 54 are disposed directly below the central element. The position of the element 52d directly above the reflection point 54 is the coordinate (x0, 0) on the xy two-dimensional coordinate, the element interval is Le, the position of the focal point 58 is the coordinate (x0, df), and the position of the reflection point 54 is the coordinate ( x0, z), the position of the transmitting element 52d is also in the same coordinate (x0, 0) as the element 52d immediately above the reflecting point 54, and the transmission beam transmitted from the transmitting element 52d through the focal point 58 to the reflecting point 54 is transmitted. The length (transmission path distance) Lta of the path 61 and the length (reception path distance) Lra of the reception path 60 of the ultrasonic echo from the reflection point 54 to the receiving element 52d are calculated by Lta = Lra = z. be able to.
Accordingly, the ultrasonic propagation distance Lua in the case of the target element data is Lua = Lta + Lra = 2z.

On the other hand, as shown in FIG. 5B, in the case of non-target element data, that is, when an ultrasonic beam is transmitted to a transmission line adjacent to the target transmission line, the positions of the central elements of the transmission elements 52d to 52f are The focal point 58 is arranged just below the element 52e, which is the central element, while being shifted by one element (x direction: right direction in the figure) with respect to the reflection point 54 (sampling point). It is arranged directly below 52d. As in the case of FIG. 6A, the position of the receiving element 52d immediately above the reflection point 54 is set to the coordinates (x0, 0) on the xy two-dimensional coordinates, the element interval is Le, and the position of the reflection point 54 is the coordinates (x0). , Z), the position of the transmitting element 52e is the coordinate (x0 + Le, 0), and the position of the focal point 58 is the coordinate (x0 + Le, df). Therefore, the transmission beam from the transmitting element 52e through the focal point 58 to the reflection point 54 The length (transmission path distance) Ltb of the transmission path 61 can be calculated by Ltb = df + √ {(z−df) ² + Le ² }, and the ultrasonic echo reception path from the reflection point 54 to the reception element 52d. The length 60 (reception path distance) Lrb of 60 can be calculated by Lrb = z.
Therefore, the ultrasonic propagation distance Lub in the case of non-target element data is Lub = Ltb + Lrb = df + √ {(z−df) ² + Le ² } + z.

In this way, the value obtained by dividing the ultrasonic propagation distance Lua by the sum of the distance Lta of the transmission path 61 and the distance Lra of the reception path 60 obtained by the geometrical arrangement shown in FIG. This is the propagation time between the ultrasonic element and the sampling point when ultrasonic waves are transmitted and received for acquisition. Also, the value obtained by dividing the ultrasonic propagation distance Lub, which is the sum of the distance Ltb of the transmission path 61 and the distance Lrb of the reception path 60 obtained by the geometric arrangement shown in FIG. This is the propagation time between the ultrasonic element and the sampling point when ultrasonic waves are transmitted and received on the transmission line adjacent to the transmission line.
The calculation of the delay time is based on the propagation time of the ultrasonic wave between the ultrasonic element and the sampling point when acquiring the element-of-interest data and between the ultrasonic element and the sampling point when acquiring the non-target element data. The delay time is obtained from the difference in ultrasonic propagation time.
6 (a) and 6 (b), the transmission path 61 is a model that passes through the focal point 58, but the present invention is not limited to this, for example, it passes through the focal point 58. Alternatively, a route that directly reaches the reflection point 54 may be used.

Note that this delay time calculation method uses a delay time in the element 52 located immediately below the sampling point as a representative value in the transmission / reception of ultrasonic waves with a certain element as the central element, and this representative value is used as the total value in this transmission / reception. This is used as the delay time of the element.
However, the present invention is not limited to this. For example, the reception path distance Lrb of the element 52c, the element 52b, or the like whose position in the x direction is different from the sampling point, that is, the element 52d immediately below is the element directly below. Depending on the number of elements n from 52d, it may be calculated as Lrb = √ {(n × Le) ² + z ² }.

Moreover, although the geometric model of Fig.6 (a) and FIG.6 (b) is a case of a linear probe, not only this but another probe can perform the same geometric calculation from the shape of a probe. . For example, in the case of a convex probe, a geometric model can be set from the radius of the probe and the angle between the elements, and the calculation can be performed in the same way.
In the case of steer transmission, a geometric model (not shown) that considers information such as the transmission angle is used, and the attention element data and the surrounding non- attention element data are determined from the positional relationship between the transmission element and the sampling point. The delay time can be calculated.
Furthermore, the delay time is not limited to the method of calculating the delay time using the geometric model, and the delay time is obtained for each measurement condition from the measurement result obtained by measuring the high-intensity reflection point according to the measurement condition of the apparatus in advance. By storing in the apparatus, the delay time of the same measurement condition may be read out.

FIG. 6C shows true element data 66 which is element data when there is a reflection point on the transmission line in the center, and element data 68 of a ghost in which a ghost is generated due to the influence of the reflection point on both sides. FIG. 6D shows the ghost element data 68, which is the non-attention element data, when the central true element data 66 obtained from the above geometric calculation is set as the attention element data. An example of delay time is shown. It is shown that when the true element data 66 is the target element data, the ghost element data 68 is symmetrically delayed.
In this way, the delay time calculated by the delay time calculation unit 48 of the element data processing unit 22 can also be used for delay correction in the phasing addition unit 38.

Next, in the superposition processing unit 50 of the element data processing unit 22 of the present invention, using the delay time thus calculated by the delay time calculating unit 48, the target element data of the target transmission line and the surrounding transmission lines are used. The non-attention element data that is the element data is overlaid.
In the superposition processing in the superposition processing unit 50, information on the number of superposition element data and the superposition processing method at the time of superposition is necessary, but these may be input in advance by the operation unit 32. Alternatively, it may be stored in the storage unit 34.

FIGS. 7A to 7H show a specific example of overlay processing performed by the overlay processor 50 when the number of element data is five and the number of overlay element data is three.
FIG. 7 (a) shows five element data obtained by performing ultrasonic transmission / reception side by side in a transmission line having five adjacent elements as the central elements, and for each element data, It shows a state in which an ultrasonic beam is transmitted and a reflected signal is received. The horizontal axis of each element data represents a receiving element, and the respective element data are displayed with the center element at the time of transmission of the ultrasonic beam as the center. The vertical axis represents the reception time.
Among the five element data, in the element data in the middle, there is a reflection point immediately below the element at the center of the element data (element at the center of the receiving element), that is, the center element at the time of transmission (transmitting element). A reflection signal (ultrasonic echo) from the reflection point is received. That is, this reflected signal is a true signal, and the element data in the middle represents the true element data.

  For the two element data on both sides other than the middle element data, there is no reflection point directly below the central element at the time of transmission, but due to the spread of the transmitted ultrasonic beam, the transmission element of the middle element data A reflected signal, i.e., a ghost, which is generated when an ultrasonic beam hits a reflection point existing directly below, is reflected. Since the propagation time of the ultrasonic wave to the reflection point becomes longer as the ghost is away from the true signal, the reception time is delayed as compared with the true element data. The position of the receiving element where the reflected signal from the reflection point is first received is the element immediately above the reflection point, but the horizontal axis of the element data is centered on the central element at the time of transmitting the ultrasonic beam. Therefore, since the center element is shifted by one element for each element data, that is, the transmission line is shifted by one line, the absolute position of the element is shifted by one element in each element data. That is, in the middle element data, the receiving element from which the reflected signal from the reflection point is received first is the middle element, but the element data on both sides is shifted by one element from the middle element data. The element data is shifted one element to the left, and the left element data is shifted one element to the right. Further, the element data at both ends are shifted by two elements from the middle element data, the leftmost element data is shifted by two elements to the left, and the leftmost element data is shifted by two elements to the right. As described above, the ghost signal is not only delayed in reception time with respect to the true signal, but also deviated from the direction of the receiving element.

FIG. 7B shows an example of the delay time of the reception time when the element data in the middle of the element data for the five elements shown in FIG.
The overlay processing unit 50 uses the delay time shown in FIG. 7B to set the element data in the middle as the element data of interest. In the example shown in FIG. The delay time correction is performed on the three element data, and the amount of deviation between the center element (target element) corresponding to the transmission line of the target element data and each center element, in the illustrated example, one element on both sides. The data is shifted in the direction, that is, the unprocessed element data corresponding to the three transmission lines is superposed with the phase being matched to obtain one overlap-processed element data corresponding to a predetermined sampling point of the target transmission line. By performing such superposition processing at each sampling point on the target transmission line, it is possible to obtain element data in which the focus is narrowed down at each sampling point on the transmission line.

FIG. 7C shows the superposed element data of the transmission line of interest obtained in this way.
Since the element data of the target element shown in FIG. 7A is the element data of the true signal, the delay time correction and the lateral shift are performed on the unprocessed element data of the adjacent elements on both sides of the target element. When the matching is performed, as shown in FIG. 7C, the unprocessed element data of the adjacent element and the unprocessed element data of the target element overlap each other at the high luminance position because the phases match. Therefore, when these element data are added, for example, the element data value shows a large value (high luminance value), and for example, even if an average value is obtained by averaging, an emphasized value (high luminance value) is shown.

On the other hand, FIG. 7D shows the same element data group as FIG. 7A, but an example in which element data on the left of the middle element data, that is, ghost element data is used as the element data of interest. Indicates.
FIG. 7E shows an example of the delay time of the reception time when the center left adjacent element is the target element. Since FIG. 7A and FIG. 7D are the same element data group, the delay time shown in FIG. 7E is the same as FIG. 7B except for the element of interest.
The overlay processing unit 50 uses the delay time shown in FIG. 7E to correct the delay time for the overlap element data, in the illustrated example, for the overlap element data, centering on the element of interest, and The amount of shift between the element and each center element, in the example shown in the figure, is shifted laterally by one element on both sides, and the unprocessed element data for three transmission lines is overlaid, and a predetermined sampling point of the target transmission line is obtained. It is obtained as one corresponding superposed processed element data. By performing such superposition processing at each sampling point on the target transmission line, it is possible to obtain element data in which the focus is narrowed down at each sampling point on the transmission line.

FIG. 7 (f) shows the superposed element data of the target transmission line thus obtained.
Since the element data of the target element shown in FIG. 7D is ghost element data, phase adjustment is performed by performing delay time correction and lateral shift on the unprocessed element data of adjacent elements on both sides of the target element. Even if it is performed, as shown in FIG. 7F, the unprocessed element data of the adjacent element and the unprocessed element data of the target element do not overlap each other because the phases do not match. For this reason, even if these three element data are added, for example, since the phases are not matched, signals that are inverted in phase cancel each other out, so the added value does not increase. When the average value is obtained, a small value is shown.

As for the other element data, the same delay time correction and lateral shift are performed as the element data of interest. As a result, the overlapping state of the element data of three adjacent transmission lines for the five element data in the illustrated example is shown in FIG. FIG. 7 (h) shows the result of, for example, addition processing or average processing as superimposing processing shown in (g).
As shown in FIG. 7 (h), in the transmission line of interest when the coordinates of the central element and the reflection point of the transmission element shown in FIG. 7 (a) are coincident (when there is a reflection point on the transmission line). The element data of the true signal is obtained as superposed processed element data having a high luminance value, and the ghost element data is added to the element data whose phases are not in phase with each other in all four elements on both sides. Or, since they will cancel each other, the ghost superimposed element data is smaller than the superimposed element data having a high luminance value whose value is the element data of the true signal. Thus, the influence of the ghost element data on the element data of the true signal can be reduced, or the influence can be reduced to the extent that the influence can be ignored.

  Note that the superimposition processing method in the superimposition processing unit 50 may not only be added, but may be an average value or a median value, or may be performed after multiplication by coefficients. Note that taking an average value or median value is thought to correspond to applying an averaging filter or median filter at the element data level, but is performed by normal image processing instead of the averaging filter or median filter. An inverse filter or the like may also be applied. Alternatively, the element data to be superimposed are compared, and if they are similar, the maximum value is taken, if not, the average value is taken, and if there is a distribution bias, the intermediate value is taken. The overlay process may be changed based on the feature amount of each element data to be superimposed.

Further, it is desirable that the number of element data to be superimposed is matched to the extent of the beam width of the ultrasonic beam. Therefore, when the beam width changes depending on the depth, the number of overlapping element data may be changed depending on the depth. Further, since the beam width depends on the transmission numerical aperture, the number of overlapping element data may be changed according to the transmission numerical aperture. Alternatively, the number of overlapping element data may be changed based on a feature quantity such as the luminance value of the image, or the optimum number of overlapping element data is selected from images created by changing the number of overlapping element data. May be.
As a result of the superposition, as described above, the signal phase matches in the element data of the true signal, but the signal phase does not match in the ghost. As a result of superposition processing such as addition, signals of various phases are mutually connected. Cancel each other and the signal becomes weaker. As a result, the true signal remains as effective element data having a valid value, for example, high luminance, and the ghost signal can be obtained as element data having a reduced value, for example, low luminance.

In the present invention, when the position of the focal point of the ultrasonic beam is within a predetermined range, the position of the focal point is reset, and ultrasonic waves are transmitted and received. Are overlapped, new element data is generated, and element data corresponding to the transmission line whose focus position is reset is obtained.
As described above, conventionally, when acquiring an ultrasound image, ultrasonic waves with good image quality in the region of interest are obtained by setting the focal point of the ultrasound beam near the region of interest and transmitting and receiving ultrasound. An image was generated. However, at a position close to the ultrasonic probe (surface layer) or a position far from the ultrasonic probe (deep layer), it is difficult in principle to converge the ultrasonic beam to the set focal position, so focus on the surface layer or the deep layer. In some cases, it has been difficult to improve the image quality of the surface layer and the deep layer.

In contrast, according to the present invention, when the focal position of the ultrasonic beam is within a predetermined range, the first element obtained by resetting the focal position and transmitting a plurality of ultrasonic beams is obtained. Second element data is generated from the data. Specifically, when the focal position of the ultrasonic beam is shallower than the predetermined depth Za (on the surface layer), the focal position is reset to a deeper position and deeper than the predetermined depth Zb ( In the deep layer), the focus position is reset to a shallower position, ultrasonic waves are transmitted / received to the reset focus position, and a plurality of unprocessed element data (first element data) obtained are obtained. Then, based on the information on the geometrical arrangement of the elements and the reception time, new processed element data (second element data) is generated.
Thereby, by resetting the focal position, the ultrasonic beam can be sufficiently converged to the set focal position and element data (first element data) can be obtained, so that the quality of the element data is improved. be able to. Furthermore, by combining a plurality of first element data obtained by resetting the focal position, it is possible to reduce the influence of a ghost generated by the spread of the ultrasonic beam even at a position away from the focal point. Thus, the same element data (second element data) as that at which the focal point is formed at each sampling point on the transmission line can be obtained. Therefore, even in the surface layer and deep layer where it is difficult to converge the focus, the SN ratio can be increased, the resolution can be increased, and the optimum spatial resolution can be achieved with a high resolution at the same frame rate as before. A sharp ultrasonic image can be obtained.
In addition, since high-quality element data can be obtained, the optimum sound speed can be obtained with high accuracy even when the optimum sound speed for each region in the inspection target area is obtained using the element data.

The operation and action of the ultrasonic inspection apparatus of the present invention and the method for creating an ultrasonic image will be described.
FIG. 8 is a flowchart for explaining the operation of the ultrasonic inspection apparatus shown in FIG.
First, the focus setting unit 96 sets the focus position according to the information input from the operation unit 32, and supplies the set focus position information to the focus resetting unit 98.
The focus resetting unit 98 determines whether or not the set focus position is within a predetermined depth range, and when the focus position is shallower than the predetermined depth Za, resets the focus position to a deeper position, When the depth is deeper than the predetermined depth Zb, the focus position is reset to a shallower position, and when the depth is between Za and Zb, the focus position information is not changed without changing the focus position. Is supplied to the transmitter 14.
When the operator abuts the ultrasonic probe 12 on the surface of the subject and starts measurement, an ultrasonic beam is transmitted from the transducer array 36 according to the drive signal supplied from the transmission unit 14, and the ultrasonic wave from the subject is transmitted. The transducer array 36 receives the echo and outputs an analog element signal as a reception signal. At this time, the transmission unit 14 drives the transducer array 36 so as to transmit an ultrasonic beam that forms a focal point at the focal position supplied from the focus resetting unit 98.
The receiving unit 16 outputs an analog element signal output from each element as one analog element data, and supplies it to the A / D converter 18. The A / D conversion unit 18 converts analog element data into digital element data, supplies the element data to the element data storage unit 20, and stores and holds the data.

  In the delay time calculation unit 48 (FIG. 3), the element data processing unit 22 delays the unprocessed element data of the transmission line of interest and the unprocessed element data of peripheral transmission lines (for example, FIG. 7B). FIG. 7E is the same.) FIG. 7E shows the geometric arrangement of the transmitting element, the focal point, the reflection point, and the receiving element, and the inspection target region of the subject that is set in advance. It is calculated from the speed of sound or the like (for example, calculated using the geometric model in FIG. 6).

Next, the element data processing unit 22 reads the unprocessed element data from the element data storage unit 20, sets the element data to be processed as the element data of interest, and in the overlay processing unit 50 (FIG. 3), the delay time calculation unit 48. Using the delay time calculated in (1), the element data of interest and the unprocessed element data (non-element of interest data) of the surrounding transmission lines are phase-matched to obtain processed element data. As a result, enhanced processed element data is obtained for unprocessed element data including a true signal, and attenuated processed element data is determined for ghost unprocessed element data.
The element data processing unit 22 superimposes each transmission line at each sampling point on the transmission line when the focus resetting unit 98 resets the focus position and when the focus position is not reset. Processing is performed to obtain processed element data. The processed element data thus obtained is supplied to the phasing addition unit 38 of the image generation unit 24.

  The phasing addition unit 38 of the image generation unit 24 performs reception focus processing on the processed element data to generate reception data (sound ray signal), and supplies the reception data (sound ray signal) to the detection processing unit 40. The detection processing unit 40 processes the sound ray signal and generates a B-mode image signal. The DSC 42 performs raster conversion on the B-mode image signal, and the image creation unit 44 performs image processing to generate an ultrasonic image. The generated ultrasonic image is stored in the image memory 46, and the ultrasonic image is displayed on the display unit 28 by the display control unit 26.

  As described above, the ultrasonic inspection apparatus 10 according to the present invention performs transmission / reception of ultrasonic waves by resetting the focal position when the focal position of the ultrasonic beam is within a predetermined range, and the obtained element The above-described element data superimposition process is performed on the data, new element data is generated, and element data corresponding to the transmission line whose focus position is reset is set. Thereby, by resetting the focal position, the ultrasonic beam can be sufficiently converged to the set focal position and element data (first element data) can be obtained, so that the quality of the element data is improved. be able to. Furthermore, by combining a plurality of first element data obtained by resetting the focal position, it is possible to reduce the influence of a ghost generated by the spread of the ultrasonic beam even at a position away from the focal point. It is possible to obtain the same element data (second element data) as the focal point is formed at each point on the transmission line. Therefore, even in the surface layer and deep layer where it is difficult to converge the focus, the SN ratio can be increased, the resolution can be increased, and the optimum spatial resolution can be achieved with a high resolution at the same frame rate as before. A sharp ultrasonic image can be obtained.

  In the above embodiment, the focus position is changed when the focal position is shallower than the predetermined depth Za or deeper than the predetermined depth Zb. However, the present invention is not limited to this. Instead, as shown in the flowchart of FIG. 9A, the focus position may be reset to a position deeper than Za when the depth is smaller than the predetermined depth Za. Alternatively, as shown in the flowchart of FIG. 9B, when the depth is deeper than the predetermined depth Zb, the focal position may be reset to a position shallower than Zb.

  In the illustrated example, the focus position set by the focus setting unit 96 is the same depth for all transmission lines. However, the present invention is not limited to this, and the focus setting unit 96 is different for each transmission line. The focal position may be set to the depth. In this case, the focus resetting unit 98 may determine the focus depth for each transmission line, and reset the focus position for the transmission line whose focus position is within a predetermined depth range. At this time, when the element data processing unit performs the overlay process using the element data of the transmission line whose focus position is reset as the target element data, the focus position of the non-target element data to be overlapped is reset. The transmission line element data may be the transmission line element data for which the focus position is not reset.

In the above embodiment, the element data to be superimposed on the target element data is the element data of the transmission line adjacent to the transmission line of the target element data. However, the present invention is not limited to this, and the element data of the target element data Any transmission line different from the transmission line may be used. In addition, when superimposing element data, it is preferable that the area | region of the transmission beam transmitted when acquiring each element data overlaps the area | region of the transmission beam transmitted when acquiring element-of-interest data. Therefore, the element data to be superimposed on the element data of interest is preferably element data of an adjacent transmission line or a nearby transmission line.
The element data to be superimposed on the target element data is preferably element data acquired with a transmission line that is symmetric about the transmission line of the target element data.

  In the above embodiment, the ultrasonic beam is transmitted in a direction orthogonal to the arrangement direction of the ultrasonic elements. However, the present invention is not limited to this, and is inclined with respect to the arrangement direction of the ultrasonic elements. It is good also as a structure which transmits an ultrasonic beam in the direction (steer) which is carrying out. Moreover, in the said Example, although it was set as the structure by which one set of transmission elements (transmission opening) and transmission of one ultrasonic beam respond | corresponded one by one, it is not limited to this, The same one set A configuration may be adopted in which a plurality of ultrasonic beams are transmitted in different directions using a transmitting element.

  In addition, the ultrasonic inspection apparatus according to the present embodiment is controlled by an ultrasonic image data generation program stored in a memory attached to a control unit (not shown). That is, the control unit reads out the ultrasound image data generation program from the memory, sets / resets the focus position according to the ultrasound image data generation program, and sets the focus position according to the set / reset focus. Transmits an ultrasonic beam toward the examiner, receives an ultrasonic echo reflected from the subject, synthesizes the first element data obtained by the reception, and generates second element data The function to perform is executed.

  Note that the ultrasonic image data generation program is not limited to the one stored in the memory attached to the control unit in this way, and the ultrasonic image data generation program may be the present ultrasonic image processing such as a CD-ROM. The information may be recorded in a memory medium (removable medium) configured to be detachable from the apparatus, and read into the apparatus via an interface corresponding to the removable medium.

  The ultrasonic inspection apparatus, the ultrasonic image data generation method, and the program according to the present invention have been described in detail above. However, the present invention is not limited to the above examples, and various types can be made without departing from the gist of the present invention. Of course, improvements and modifications may be made.

DESCRIPTION OF SYMBOLS 10 Ultrasonic inspection apparatus 12 Ultrasonic probe 14 Transmission part 16 Reception part 18 A / D conversion part 20 Element data storage part 22 Element data processing part 24 Image generation part 26 Display control part 28 Display part 30 Control part 32 Operation part 34 Storage Unit 36 transducer array 38 phasing addition unit 40 detection processing unit 42 DSC
44 Image creation unit 46 Image memory 48 Delay time calculation unit 50 Overlay processing unit 52 Element 54 Reflection point 56 Transmit beam 58 Focus 60 Receive path 62 Element data 64 Transmit beam 66 True element data 68 Ghost element data 96 Focus setting unit 98 Focus reset section

Claims (18)

An ultrasonic diagnostic apparatus for inspecting an inspection object using an ultrasonic beam,
A probe in which a plurality of elements are arranged, which transmits the ultrasonic beam, receives an ultrasonic echo reflected by the inspection object, and outputs an analog element signal corresponding to the received ultrasonic echo With the child,
A focus setting unit for setting a plurality of transmission focal points in the inspection object;
A focus resetting unit that determines whether the position of the transmission focus set by the focus setting unit is within a predetermined range and resets the position of the transmission focus within the predetermined range to a different position;
For each of the transmission focus determined to be out of a predetermined range by the focus resetting unit and the reset transmission focus, a plurality of the elements are used in the probe, and the ultrasonic beam is A transmission unit for transmission;
In response to transmission of the individual ultrasonic beams for each of the transmission focal points, a receiving unit that receives analog element signals output from the plurality of elements and performs predetermined processing;
A / D conversion of the analog element signal processed by the reception unit to obtain first element data which is a digital element signal;
The first element obtained by transmitting the ultrasonic beam from the first element data obtained by transmitting a plurality of the ultrasonic beams to the transmission focus reset by the focus resetting unit. An ultrasonic inspection apparatus, comprising: an element data processing unit that generates second element data corresponding to the data.   The ultrasonic inspection apparatus according to claim 1, wherein the focus resetting unit resets the transmission focus to a depth different from the transmission focus set by the focus setting unit.   The focus resetting unit resets the transmission focus at a different position on the same line as the line for transmitting the ultrasonic beam with respect to the transmission focus set by the focus setting unit. Ultrasonic inspection equipment.   When the depth of the transmission focus set by the focus setting unit is shallower than a predetermined depth, the focus resetting unit is a position deeper than the position set by the focus setting unit. The ultrasonic inspection apparatus according to claim 1, which is reset to   When the depth of the transmission focus set by the focus setting unit is deeper than a predetermined depth, the focus resetting unit is a position shallower than the position set by the focus setting unit. The ultrasonic inspection apparatus according to any one of claims 1 to 4, wherein the ultrasonic inspection apparatus is reset.   The transmission unit causes the probe to use the plurality of elements and transmit the ultrasonic beam to each of the transmission focal points by changing a central element. The ultrasonic inspection apparatus according to any one of 5.   The ultrasonic diagnostic apparatus according to claim 1, wherein the element data processing unit uses the first element data obtained by transmitting a plurality of the ultrasonic beams having different central elements.   The ultrasonic diagnosis according to claim 1, wherein the element data processing unit uses the first element data obtained by transmitting a plurality of the ultrasonic beams, in which transmission areas of ultrasonic beams overlap. apparatus.   The element data processing unit superimposes a plurality of the first element data according to a reception time when the element receives an ultrasonic echo and a position of the element, and corresponds to the first element data. The ultrasonic diagnostic apparatus according to claim 1, wherein the device data is generated.   The element data processing unit synthesizes a plurality of the first element data obtained by transmitting an ultrasonic beam with an element continuous in the arrangement direction of the elements as a center element, and the second element data The ultrasonic inspection apparatus according to claim 1, which generates element data.   The element data processing unit is configured to transmit a plurality of ultrasonic beams obtained by transmitting the ultrasonic beam using the same number of elements adjacent to the central element corresponding to the ultrasonic beam whose transmission focus is reset as the central element. The ultrasonic inspection apparatus according to claim 1, wherein the second element data is generated by synthesizing the first element data.   The element data processing unit includes: a delay time calculation unit that calculates a delay time of two or more first element data; a delay time that calculates two or more first element data; and the received probe The ultrasonic inspection apparatus according to claim 1, further comprising: an overlay processing unit configured to superimpose based on a position of a child element and generate the second element data. The delay time calculation unit includes the probe acquired in advance, the speed of sound of the inspection object, the position of the transmission focal point of the ultrasonic beam, the transmission opening of the probe by the transmission unit, and the reception unit Calculating a delay time of the two or more first element data based on at least one piece of information regarding the receiving aperture of the probe according to
The superimposition processing unit sets two or more first element data based on a preset number of first element data to be superimposed among the two or more first element data and an overlay processing method. The ultrasonic inspection apparatus according to claim 12, wherein the second element data is generated by superimposing the data.   The super-element according to any one of claims 1 to 13, wherein the element data processing unit superimposes two or more first element data after multiplying each of the first element data by a weighting coefficient. Sonographic equipment.   15. The transmitter according to claim 1, wherein the transmitter causes the probe to transmit the ultrasonic beam to the transmission focus before reset, which is determined to be within a predetermined range by the focus resetting unit. The ultrasonic inspection apparatus according to Crab.   The ultrasonic inspection apparatus according to claim 1, further comprising an element data holding unit that holds all of the first element data output by the receiving unit. The ultrasonic beam is generated by a probe having a plurality of elements that generates each component of the ultrasonic beam, receives an ultrasonic echo reflected in the inspection object, and outputs a received analog signal. An ultrasonic image data generation method for inspecting the inspection object and generating ultrasonic image data,
A focus setting step for setting a predetermined transmission focus in the inspection object;
A focus resetting step for determining whether or not the position of the transmission focus set by the focus setting step is within a predetermined range, and resetting the position of the transmission focus within the predetermined range to a different position;
For each of the transmission focus determined to be out of a predetermined range by the focus resetting unit and the reset transmission focus, a plurality of the elements are used in the probe, and the ultrasonic beam is A transmission step for transmission;
In response to transmission of the individual ultrasonic beams to each of the transmission focal points, a reception step of receiving analog element signals output from the plurality of elements and performing predetermined processing;
A / D conversion of the analog element signal processed in the reception step to obtain first element data that is a digital element signal;
The first element obtained by transmitting the ultrasonic beam from the first element data obtained by transmitting a plurality of the ultrasonic beams to the transmission focus reset by the focus resetting step. And an element data processing step of generating second element data corresponding to the data. The ultrasonic beam is generated by a probe having a plurality of elements that generates each component of the ultrasonic beam, receives an ultrasonic echo reflected in the inspection object, and outputs a received analog signal. An ultrasonic image data generation program for causing a computer to inspect the inspection object and generate ultrasonic image data,
A focus setting step for setting a predetermined transmission focus in the inspection object;
A focus resetting step for determining whether or not the position of the transmission focus set by the focus setting step is within a predetermined range, and resetting the position of the transmission focus within the predetermined range to a different position;
For each of the transmission focus determined to be out of a predetermined range by the focus resetting unit and the reset transmission focus, a plurality of the elements are used in the probe, and the ultrasonic beam is A transmission step for transmission;
In response to transmission of the individual ultrasonic beams to each of the transmission focal points, a reception step of receiving analog element signals output from the plurality of elements and performing predetermined processing;
A / D conversion of the analog element signal processed in the reception step to obtain first element data that is a digital element signal;
The first element obtained by transmitting the ultrasonic beam from the first element data obtained by transmitting a plurality of the ultrasonic beams to the transmission focus reset by the focus resetting step. An ultrasonic image data generation program causing a computer to execute an element data processing step of generating second element data corresponding to data.

Images