Ultrasonic diagnostic apparatus and control method thereof

Abstract

The present invention relates to an ultrasonic diagnostic apparatus and a control method thereof. A control section (40) cyclically sets a first transmission / reception condition for a short distance and a second transmission / reception condition for a long distance. In a combining section (24), an added frame column and an edge emphasis frame column are generated from a received frame column, and a combined frame column is generated from them. In the first transmission / reception condition, a first transmission frequency and a first transmission focal depth are included. In the second transmission / reception condition, a second transmission frequency lower than the first transmission frequency and a second transmission focal depth deeper than the first transmission focal depth are included.

Description

Technical Field

[0001] This disclosure relates to ultrasound diagnostic apparatus and control methods thereof, and more particularly to techniques for improving the quality of ultrasound images. Background Technology

[0002] An ultrasound diagnostic device is a medical device that generates ultrasound images by transmitting ultrasound waves into and receiving ultrasound waves from a living organism (subject). Specifically, by repeatedly electronically scanning the ultrasound beam, a sequence of receiving frames (multiple receiving frame data) arranged in a time-series order is generated. Based on this sequence of receiving frames, a sequence of display frames (multiple display frame data) is generated. The display frame sequence is then displayed as a moving image.

[0003] As a technique for improving the image quality of ultrasound images, it is known to generate composite frames based on each frame set in a received frame series. Specifically, a composite frame is generated by generating multiple intermediate frames based on a frame set and then combining them. Methods for generating intermediate frames include addition and edge extraction.

[0004] The additive method generates a summed frame by adding multiple frames that make up the frame set. The edge extraction method extracts edge components based on multiple frames that make up the frame set and generates an emphasized edge frame.

[0005] In the ultrasound diagnostic apparatus described in Document 1 (Japanese Patent Application Publication No. 2018-153415), a summation frame and edge-emphasis frames are generated as multiple intermediate frames based on multiple frames constituting a frame set, and a composite frame is generated by weighted summation of these frames. Wavelet fusion is used when generating the edge-emphasis frames. The technique described in Document 1 improves the blurring that occurs with the summation of multiple frames by mixing edge components. Wavelet fusion is also disclosed in Document 2 (Japanese Patent Application Publication No. 2011-56249). Neither Document 1 nor Document 2 describes the variation of the transmission focus depth within a frame set having the same diagnostic depth range.

[0006] Other techniques for improving the image quality of ultrasound images include spatial composite and frequency composite methods. These methods generate composite frames by combining multiple frames with different properties. Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The purpose of this disclosure is to improve image quality across the entire ultrasound image. Alternatively, the purpose of this disclosure is to improve image quality in both the region near the probe (shallow region) and the region far from the probe (deep region).

[0009] Methods for solving problems

[0010] The ultrasonic diagnostic apparatus disclosed herein is characterized by comprising: a generation unit that generates a frame series by repeatedly generating a transmitted signal and processing a received signal according to a plurality of cyclically set transceiver conditions; and a synthesis unit that generates a synthesized frame series according to the frame series, and generates a synthesized frame based on a plurality of frames constituting each frame set in the frame series, wherein the plurality of transceiver conditions include a first transceiver condition for near-range transmission and a second transceiver condition for long-range transmission, the first transceiver condition includes a first transmission frequency and a first transmission focal depth, and the second transceiver condition includes a second transmission frequency lower than the first transmission frequency and a second transmission focal depth deeper than the first transmission focal depth.

[0011] The control method for an ultrasound diagnostic apparatus disclosed herein is characterized by comprising: a step of generating a frame series by repeatedly generating a transmitted signal and processing a received signal according to a plurality of cyclically set transmit and receive conditions; a step of generating a plurality of intermediate frames with different properties based on each frame set in the frame series; a step of generating a composite frame for ultrasound image formation by assembling the plurality of intermediate frames according to each of the frame sets; a step of calculating an evaluation value based on at least one of the plurality of intermediate frames; and a step of changing the combination of a plurality of transmission frequencies included in the plurality of transmit and receive conditions based on the evaluation value. Attached Figure Description

[0012] Figure 1 This is a block diagram showing the structure of the ultrasound diagnostic apparatus according to the first embodiment.

[0013] Figure 2 This is a schematic diagram showing the processing in the synthesis section.

[0014] Figure 3 This is a diagram illustrating the method for determining the two focal depths.

[0015] Figure 4 This is a diagram illustrating the selection method for frequency pairs.

[0016] Figure 5 This is a schematic diagram illustrating the second embodiment.

[0017] Figure 6 This is a diagram illustrating the third embodiment.

[0018] Figure 7 This is a diagram illustrating the fourth embodiment. Detailed Implementation

[0019] The following description, based on the accompanying drawings, illustrates the implementation method.

[0020] (1) Overview of the implementation method

[0021] The ultrasound diagnostic measure according to the embodiment includes a generation unit and a synthesis unit. The generation unit generates a frame series by repeatedly generating a transmitted signal and processing a received signal according to a plurality of cyclically set transmission and reception conditions. The generation unit is equivalent to a transmission and reception unit. The synthesis unit generates a synthesized frame series based on the frame series. Specifically, the synthesis unit generates a synthesized frame based on a plurality of frames constituting each frame set in the frame series. The plurality of transmission and reception conditions include a first transmission and reception condition for near-range and a second transmission and reception condition for long-range. The first transmission and reception condition includes a first transmission frequency and a first transmission focal depth, and the second transmission and reception condition includes a second transmission frequency lower than the first transmission frequency and a second transmission focal depth deeper than the first transmission focal depth.

[0022] In the above structure, the frame set consists of multiple frames with different properties. A composite frame is generated by combining these frames. Since the first transmit / receive condition for near range and the second transmit / receive condition for long range are applied during the frame set generation process, the combination of the first transmit frequency and the first focal depth, as well as the combination of the second transmit frequency and the second transmit depth, can be selectively applied. Therefore, the image quality (especially spatial resolution and sensitivity) for both near and far range regions can be improved in the composite frame generated by the combining unit.

[0023] In this implementation, the diagnostic depth range can be maintained while applying multiple transmit / receive conditions in stages. In this respect, the technology involved in this implementation differs from conventional multi-level focusing transmission techniques. Furthermore, multiple transmit focus depths are set in stages while applying multiple transmit / receive conditions in stages. In this respect, the technology involved in this implementation differs from conventional frequency compositing methods. The multiple transmit / receive conditions consist of two or more transmit / receive conditions. A frame series is a concept that includes both receive frame series and display frame series.

[0024] Furthermore, the transmission focal depth is generally defined as the distance from the transceiver wavefront in a direction orthogonal to the transceiver wavefront (usually the surface in contact with the organism) when using electronic linear scanning (including electronic convex scanning), and as the distance from the transceiver origin when using electronic sector scanning. The transmission frequency is generally the transmission center frequency.

[0025] The ultrasound diagnostic apparatus according to the embodiment includes a control unit. The control unit sets a first transmission focal depth and a second transmission focal depth based on the diagnostic depth range. This structure reduces the user's workload and improves the image quality of the ultrasound image. For example, a first ratio can be specified for near-field focus, and a second ratio can be specified for far-field focus. In this case, the near-field transmission focal depth can be automatically specified by multiplying the diagnostic depth range (the maximum depth for imaging) by the first ratio; similarly, the far-field transmission focal depth can be automatically specified by multiplying the diagnostic depth range by the second ratio.

[0026] In this implementation, the first transmit / receive condition includes a first receive passband. The second transmit / receive condition includes a second receive passband that is narrower than the first receive passband. Generally, a dynamic receive filter is used during reception. That is, a technique is employed to dynamically change the passband based on changes in the receive focus depth. The first and second receive passbands are passbands within a given depth, a given depth range, or an overall depth range, respectively. For example, at both the first and second transmit focus depths, the second receive passband may be narrower than the first receive passband.

[0027] In this embodiment, the first transmit / receive condition includes a first beam deflection angle, and the second transmit / receive condition includes a second beam deflection angle different from the first beam deflection angle. This structure combines spatial recombination with the structure described above.

[0028] The ultrasonic diagnostic apparatus according to the embodiment includes a vibrating element array, which is composed of a plurality of vibrating elements arranged along a primary direction and a secondary direction. A first aperture size, which is the aperture size in the secondary direction, is included in the first transceiver condition, and a second aperture size, which is the aperture size in the second transceiver condition and is different from the first aperture size, is included in the second transceiver condition.

[0029] In this embodiment, the compositing unit includes: a first compositing unit that generates multiple intermediate frames with different properties based on a frame set; and a second compositing unit that generates a composite frame by compositing the multiple intermediate frames. In this embodiment, the first compositing unit generates an additive image and an edge-emphasis image as multiple intermediate frames. The second compositing unit generates the composite frame by compositing the additive image and the edge-emphasis image. According to this structure, sensitivity is improved by utilizing the additive image. Spatial resolution is improved by utilizing the edge-emphasis image. In other words, blurring generated in the additive image can be improved by mixing edge components.

[0030] The ultrasound diagnostic apparatus according to the embodiment includes: a calculation unit that calculates an evaluation value based on at least one of a plurality of intermediate frames; and a control unit that changes a combination of a first transmission frequency and a second transmission frequency based on the evaluation value. The characteristics of the subject (e.g., the amount of fat) are reflected in the plurality of intermediate frames. By referring to a portion and all of the plurality of intermediate frames, an evaluation value representing the characteristics of the subject can be obtained. Optimizing the combination of the plurality of transmission frequencies based on the evaluation value is desired.

[0031] In this implementation, multiple intermediate frames include a summed image and an edge-emphasis image. The evaluation value corresponds to the difference between the summed image and the edge-emphasis image. For example, the difference between the summed image and the edge-emphasis image corresponds to the amount of edge. In cases where there are few edges, the combination of transmission frequencies is varied to increase the edge count.

[0032] The control method for the ultrasound diagnostic apparatus according to the embodiment includes a first step, a second step, a third step, a fourth step, and a fifth step. In the first step, a frame series is generated by repeatedly generating a transmitted signal and processing a received signal according to multiple cyclically set transmit and receive conditions. In the second step, multiple intermediate frames with different properties are generated based on each frame set in the frame series. In the third step, a composite frame for ultrasound image formation is generated by combining the multiple intermediate frames according to each frame set. In the fourth step, an evaluation value is calculated based on at least one of the multiple intermediate frames. In the fifth step, the combination of multiple transmission frequencies included in the multiple transmit and receive conditions is changed based on the evaluation value.

[0033] Based on the above structure, the image quality of ultrasound images can be improved. In particular, it is possible to feed back information generated during the synthesis process to the setting of transmission and reception conditions. For example, a relatively higher transmission frequency pair can be selected for subjects with less body fat, and a relatively lower transmission frequency pair can be selected for subjects with more body fat.

[0034] In this implementation, the multiple intermediate frames include summation frames and edge-emphasis frames. The evaluation value is equivalent to the difference between the summation frames and the edge-emphasis frames. The evaluation value can also be calculated by accumulating the difference over the entire frame or within a portion thereof. Referring only to the edge-emphasis frames is also considered.

[0035] (2) Details of the implementation method

[0036] exist Figure 1 The image shows an ultrasound diagnostic apparatus according to the first embodiment. The tissue targeted for diagnosis is, for example, the liver. Other tissues, such as the heart and fetus, can also be targeted for diagnosis.

[0037] The probe 10 has a probe head that contacts the organism. Within the probe head is an array of one-dimensionally arranged transducers. These transducers can be arranged in a straight line or an arc. Alternatively, as described later, an array of two-dimensionally arranged transducers can also be used.

[0038] During transmission, multiple transmission signals are supplied to the vibrating element array from the transmitting unit 20. This causes ultrasound waves to radiate into the biological body, forming a transmission beam. During reception, the vibrating element array receives reflected waves from the biological body and outputs multiple reception signals to the receiving unit 22. The receiving unit 22 applies phase alignment and addition (delay and summing) to the multiple reception signals, thereby generating a phase-aligned and added reception signal. This reception signal corresponds to the reception beam.

[0039] An ultrasonic beam is essentially a combined beam of transmitting and receiving beams. The ultrasonic beam is electronically scanned. Known electronic scanning methods include linear electronic scanning (including convex electronic scanning) and sector electronic scanning. One received frame (received frame data) is obtained through one electronic scan of the ultrasonic beam. A received frame consists of multiple beam data arranged along the electronic scanning direction. Each beam data consists of multiple echo data arranged along the depth direction. By repeatedly electronically scanning the ultrasonic beam, multiple received frames arranged in a time sequence are generated. These constitute a received frame series. Furthermore, in... Figure 1 In the diagram, symbol 16 represents the ultrasonic beam (or transmitting beam), and symbol 18 represents the transmitting focus.

[0040] The receiver 22 shown in the figure has multiple A / D converters, multiple delay circuits, summing circuits, etc. Furthermore, the receiver 22 has a detector circuit, a logarithmic conversion circuit, etc. All or some of the multiple functions of the receiver 22 are implemented through hardware or software. The transmitter 20 and the receiver 22 function as generators for generating received frame sequences.

[0041] In this embodiment, the control unit 40 cyclically sets multiple transmission and reception conditions. In the first embodiment, the multiple transmission and reception conditions consist of a first transmission and reception condition for short-range use and a second transmission and reception condition for long-range use. Specifically, the first transmission and reception condition is composed of a first parameter set PS1, and the second transmission and reception condition is composed of a second parameter set PS2. Each transmission and reception condition includes the transmission frequency, transmission focus depth, and receive passband (the BPF used), etc. The two transmission and reception conditions are set alternately for each frame.

[0042] Specifically, the first transmit / receive condition includes a first transmit frequency f1, a first transmit focus depth d1, and a first receive frequency band (BPF1), and the second transmit / receive condition includes a second transmit frequency f2, a second transmit focus depth d2, and a second receive frequency band (BPF2). Here, there exists a relationship of f1 > f2 and d1 < d2.

[0043] A receive dynamic filter is applied during reception. For example, at one or both of the transmit focus depths d1 and d2, the passband of BPF2 is narrower than that of BPF1. Alternatively, the passband of BPF2 is narrower than that of BPF1 throughout the entire diagnostic depth range.

[0044] When forming the first scanning surface 12, a first transceiver condition suitable for image visualization of the region near the probe 10 is set. When forming the second scanning surface 14, a second transceiver condition suitable for image visualization of the region far from the probe 10 is set. By cyclically setting the first and second transceiver conditions, the first scanning surface 12 and the second scanning surface 14 can be generated alternately. In other words, first and second receive frames with different properties can be obtained cyclically.

[0045] The control unit 40 controls the cyclic setting of multiple transmit and receive conditions as described above. Specifically, for the transmitting unit, a first transmit frequency f1 and a first transmit focus depth d1 are assigned, and a second transmit frequency f2 and a second transmit focus depth d2 are assigned. Similarly, for the receiving unit 22, the control unit 40 specifies a first receive passband (BPF1) when forming the first scan plane 12, and specifies a second receive passband (BPF2) when forming the second scan plane 14.

[0046] The diagnostic depth range is the same between the first and second transmit / receive conditions. The diagnostic depth range is specified or preset by the user. In this embodiment, the control unit 40 automatically sets the first transmit focus depth d1 and the second transmit focus depth d2 based on the diagnostic depth range dmax. This will be described in detail later.

[0047] The receiving unit 22 outputs a series of received frames. In the illustrated structural example, the received frames are sent to the combining unit 24. The combining unit 24 is, for example, a processor. The processor (e.g., a CPU) constituting the control unit 40 can also function as the combining unit 24.

[0048] The synthesis unit 24 generates a display frame sequence based on the received frame sequence. The memory 26 is, for example, a semiconductor memory with a ring buffer structure. Two or three frame memories may also be provided as the memory 26. The received frame sequence is stored in the memory 26. Each stored received frame is the detected data and the data before scan conversion. Synthesis processing can also be applied to the RF frame sequence before detection and the display frame sequence.

[0049] The summing frame generator 28 and the edge-emphasis frame generator 30 function as an intermediate frame generation unit (first synthesis unit). The synthesizer 32, described later, functions as a second synthesis unit. In the received frame series, a received frame set is defined for each of the individual received frames. For example, the received frame acquired at the current time point and the previous received frame constitute the received frame set. The received frame set is shifted along the time axis in units of received frames.

[0050] The summation frame generator 28 adds the two received frames that constitute each received frame set to generate a summation frame. At this time, simple addition (average processing) and weighted addition (weighted average processing) are applied according to each spatial address on the scan plane. By adding the two received frames, the sensitivity can be substantially improved. By applying the above processing to each received frame set, a summation frame sequence can be generated based on the received frame sequence.

[0051] The edge-emphasis frame generator 30 applies wavelet fusion to the two received frames constituting each set of received frames to generate edge-emphasis frames. Specifically, wavelet transform is applied to each of the two received frames individually, thereby generating two transformed frames. A fused frame is generated by fusing the two transformed frames. The edge-emphasis frame is generated by performing an inverse transform (inverse wavelet transform) on the fused frame. When fusing the two transformed frames, a method is employed to preserve or emphasize the edge components. For example, the maximum value method can be used.

[0052] Edge-emphasis frames can also be generated using methods other than wavelet fusion. For example, differential methods or edge extraction filters can be used. However, wavelet fusion allows for the exclusion of blurred components and the easy extraction of sharp components. In the edge-emphasis frame generator 30, an edge-emphasis frame series is generated based on the received frame series.

[0053] The synthesizer 32 generates a composite frame by weighted summing of two intermediate frames, i.e., the summed frames, and edge-emphasis frames. Specifically, weighted summing is performed according to each address on the scan plane. The weighting coefficients used are either fixedly set or dynamically set. By summing each edge-emphasis frame for each summed frame, a high-quality frame with emphasized edges, i.e., an edge-emphasis frame, can be generated. By blending edge-emphasis frames, the spatial resolution in the depth direction can be improved. The synthesizer 32 generates a composite frame sequence based on the summed frame sequence and the edge-emphasis frame sequence.

[0054] The DSC (Digital Scan Converter) 34 generates a display frame sequence based on the received frame sequence (specifically, a synthesized frame sequence). The DSC 34 is configured by a processor. Alternatively, the DSC 34 can be implemented using a processor that constitutes the control unit 40. The DSC 34 has coordinate transformation, pixel interpolation, and frame rate conversion functions, among others. The individual display frames constituting the display frame sequence, for example, form a tomographic image.

[0055] The display processing unit 36 ​​has image synthesis and color calculation functions, etc. The display frame series is sent to the display 38 via the display processing unit. The display 38 displays an ultrasound image. Specifically, the display 38 displays a tomographic image as a motion image.

[0056] Control unit 40 control Figure 1 The operation of the multiple components shown is described. In this embodiment, as already explained, the control unit 40 cyclically sets multiple transmit and receive conditions. An operation panel 42 is connected to the control unit 40. The operation panel 42 has multiple switches, multiple knobs, a trackball, a keyboard, etc. The display 38 is composed of an LCD, an organic EL display device, etc.

[0057] exist Figure 2 The diagram schematically illustrates the processing within the synthesis unit. Memory 26 temporarily stores the received frame column 44. Figure 2 The diagram shows received frames F1, F2, and F3, with the most recent received frame being F3. Each received frame constitutes a frame set. In the illustrated example, received frames F2 and F3 form one set of received frames, while received frames F1 and F2 form another set of received frames.

[0058] The summation frame generator 28 adds the two received frames that make up each set of received frames to generate a summation frame. For example, summation frame S12 is generated based on received frames F1 and F2. Similarly, summation frame S23 is generated based on received frames F2 and F3. In this case, simple addition, weighted addition, etc., can be used. Summation frame sequence 45 is generated based on received frame sequence 44.

[0059] The edge-emphasis frame generator 30 generates edge-emphasis frames for each set of received frames by applying wavelet fusion to the two received frames that constitute it. For example, edge-emphasis frame E23 is generated based on received frames F2 and F3. Similarly, edge-emphasis frame E12 is generated based on received frames F1 and F2. Thus, edge-emphasis frame sequence 46 is generated based on received frame sequence 44.

[0060] Synthesizer 32 combines the summed frames and edge-emphasis frames for each received frame set to generate a composite frame. For example, composite frame R12 is generated by combining summed frame S12 and edge-emphasis frame E12. Similarly, composite frame R23 is generated by combining summed frame S23 and edge-emphasis frame E23. As a result, composite frame series 47 is generated based on received frame series 44.

[0061] In one implementation, for example, a weight of 0.8 is assigned to the summing frame and a weight of 0.2 is assigned to the edge-emphasis frame. The relationship between the two weights can also be dynamically changed depending on the situation.

[0062] exist Figure 2 In the diagram, symbol 50 represents the content of the wavelet fusion method. Transformed frames 52 and 54 are generated by performing wavelet transforms W on the received frames F1 and F2 respectively. Frames 52 and 54 are then fused to generate the fused frame 56. At this point, methods such as the maximum value method can be used. The inverse transform W on the fused frame 56... -1 To generate edge-emphasis frame E12.

[0063] exist Figure 3 The method for determining the transmission focus depth is shown in the diagram. A diagnostic depth range 62 is set by the user (e.g., 60). The control unit 40 determines the near-range transmission focus depth 64 by multiplying the diagnostic depth range 62 by a first ratio, and further determines the long-range transmission focus depth 66 by multiplying the diagnostic depth range 62 by a second ratio. The first and second ratios are predetermined and then set by the user. For example, the first ratio is 1 / 3 and the second ratio is 2 / 3. This process allows for automatic optimization of the two transmission focus depths. On the screen, the two transmission focus depths are displayed using two markers.

[0064] exist Figure 4 The method for selecting frequency pairs is shown in the diagram. Additionally, in... Figure 4 In the middle, to and Figure 2 The same elements shown are labeled with the same symbols, and their descriptions are omitted.

[0065] The differential calculator 68 calculates the difference between the summed frame S12 generated from the same set of received frames and the edge-emphasis frame E12. Specifically, the difference is calculated for each address on the scan plane (frame), and the sum of the differences is calculated over the entire frame. The sum is used as an evaluation value representing the amount of edge.

[0066] The frequency selector 70 selects a specific transmission frequency pair from two transmission frequency pairs registered in the memory 71. In the illustrated structural example, three transmission frequencies fa, fb, and fc are defined within the frequency band of the probe or within the frequency range generated by the transmitting unit. They have a relationship of fa < fb < fc. For example, initially, the transmission frequency pair (fb, fc) is selected. Then, if the calculated difference is less than a given threshold, i.e., if the margin is small, for example, due to a large amount of fat in the subject, it is necessary to reduce the transmission frequency, and thus another transmission frequency pair (fa, fb) is selected.

[0067] Alternatively, more than three sets of transmission frequencies can be prepared, and the optimal set can be selected based on the differential. Other parameters (such as the receive passband) can also be changed based on the differential. The differential can be calculated for each frame, or the average differential can be calculated over a certain time range. Alternatively, after the ultrasonic inspection begins, trial transmission and reception can be repeatedly performed for a certain period, and the transmission frequency set can be automatically optimized based on the differential obtained during this period.

[0068] exist Figure 5 The synthesis process involved in the second embodiment is shown in the diagram. Figure 5 In the middle, to and Figure 2 The same elements shown are labeled with the same symbols, and their descriptions are omitted. The ultrasound diagnostic apparatus according to the second embodiment generally has the same... Figure 1 The structure shown is the same. The different parts will be explained below.

[0069] In the second embodiment, a spatial composite method is performed. That is, the first beam deflection angle is initially set, followed by the second beam deflection angle, and then the third beam deflection angle. This series of settings is repeated cyclically. This generates a series of received frames 72. In the illustrated example, the first beam deflection angle is represented as +θ1, the second beam deflection angle as 0, and the third beam deflection angle as -θ1.

[0070] In the illustrated example, a set of transmit / receive conditions is formed by one long-range transmit / receive condition, one short-range transmit / receive condition, and another long-range transmit / receive condition, which are set cyclically. One long-range transmit / receive condition includes a first beam offset angle +θ1, a transmit frequency f2, a transmit focus depth d2, and a second receive passband (BPF2). The short-range transmit / receive condition includes a second beam offset angle θ1, a transmit frequency f1, a transmit focus depth d1, and a first receive passband (BPF1). Here, f1 > f2, and d1 < d2. Furthermore, the first receive passband (BPF1) is wider than the second receive passband (BPF2). Another long-range transmit / receive condition includes a third beam offset angle -θ1, a transmit frequency f2, a transmit focus depth d2, and a second receive passband (BPF2).

[0071] Addition frame generator 28 adds the three received frames that make up each received frame set to generate an added frame (see S1-3, S2-4, S3-5). Addition frame sequence 74 is generated based on received frame sequence 72. Edge emphasis frame generator 30 generates edge emphasis frames based on the three received frames that make up each received frame set (see E1-3, E2-4, E3-5). A maximum value method, etc., is applied to the three transformed frames to generate a fused frame. An edge emphasis frame is generated through this inverse transformation. Edge emphasis frame sequence 76 is generated based on received frame sequence 72.

[0072] The synthesizer 32 generates the composite frame series 78 based on the summed frame series 74 and the edge-emphasis frame series 76 (refer to R1-3, R2-4, R3-5). In addition, the transmission frequency, transmission focus depth, and reception passband can be switched between one long-distance transmit / receive condition and another long-distance transmit / receive condition.

[0073] exist Figure 6 The third embodiment is shown in the figure. The ultrasound diagnostic apparatus according to the third embodiment includes... Figure 1 The structure shown is the same. Table 80 shows the first transceiver condition 82 for short-range use and the second transceiver condition 84 for long-range use. In the third embodiment, the aperture size in the minor axis direction (the secondary direction described later) is changed. Specifically, the first transceiver condition 82 for short-range use includes a large aperture size, and the second transceiver condition 84 for long-range use includes a small aperture size.

[0074] Symbol 10A illustrates the probe according to the third embodiment. The probe 10A includes a vibrating element array 86. The x-direction represents the main direction as the electron scanning direction, and the y-direction represents the secondary direction. The vibrating element array 86 is composed of a plurality of vibrating elements 86a arranged along the x-direction and the y-direction.

[0075] In the vibrating element array 86, when only the aperture is variable in the y-direction, the probe 10A is referred to as a 1.25D type probe. In the vibrating element array 86, when both the aperture and electronic focusing are performed in the y-direction, the probe 10A is referred to as a 1.5D type probe. In the vibrating element array 86, when the aperture is variable, electronic focusing is performed, and beam deflection is performed within a certain angular range in the y-direction, the probe 10A is referred to as a 1.75D type probe.

[0076] In the third embodiment, as described above, the first transceiver condition 82 for short-range use includes setting a large aperture (maximum aperture) 88 in the vibrating element array 86 as the aperture in the y-direction. The second transceiver condition 84 for long-range use includes setting a small aperture 90 in the vibrating element array 86 as the aperture in the y-direction.

[0077] Conversely, in the first transceiver condition 82 for short-range use, a small aperture may be set in the vibrating element array 86 as the aperture in the y-direction, and in the second transceiver condition 84 for long-range use, a large aperture may be set in the vibrating element array 86 as the aperture in the y-direction.

[0078] exist Figure 7 The fourth embodiment is shown in the figure. The ultrasound diagnostic apparatus according to the fourth embodiment includes... Figure 1 The structure shown is the same. Table 92 shows the short-range transceiver conditions 94, medium-range transceiver conditions 96, and long-range transceiver conditions 98. In short-range transceiver condition 94, the transmission frequency is a higher frequency H, the transmission focus depth is d1, and the receive passband is wide. In medium-range transceiver condition 96, the transmission frequency is an intermediate frequency M, the transmission focus depth is d2, and the receive passband is wide. In long-range transceiver condition 98, the transmission frequency is a lower frequency L, the transmission focus depth is d3, and the receive passband is narrow. Here, there is a relationship of H > M > L, and a relationship of d1 < d2 < d3. The receive passband is, for example, the receive passband when the receiving point is at a given depth.

[0079] In the above embodiments, when generating a single composite frame from multiple received frames, a larger weight can be assigned to the latest received frame. In this case, correlation values ​​can be calculated between each frame, and the weights assigned to the multiple received frames can be changed based on these correlation values. Alternatively, correlation values ​​for phase information can be calculated between frames.

[0080] The above-described technique can also be used when generating an ultrasound image with a puncture needle image. For example, a first transmit / receive condition for more clearly displaying the tissue and a second transmit / receive condition for clearly displaying the puncture needle can be set cyclically. In this case, the number of times the second transmit / receive condition is set per unit time can be greater than the number of times the first transmit / receive condition is set per unit time.

Claims

1. An ultrasonic diagnostic device, characterized in that, include: The generation unit (20, 22) generates a frame series by repeatedly generating a transmission signal and processing a reception signal according to multiple cyclically set transmission and reception conditions. and The compositing unit (24) generates a composite frame series based on the frame series, and generates a composite frame based on the multiple frames constituting each frame set in the frame series. The plurality of transmission and reception conditions include a first transmission and reception condition for short-range use and a second transmission and reception condition for long-range use. The first transmit / receive condition includes a first transmit frequency and a first transmit focus depth. The second transmit / receive condition includes a second transmit frequency lower than the first transmit frequency and a second transmit focus depth deeper than the first transmit focus depth. The synthesis unit (24) includes: The first synthesis unit (28, 30) generates multiple intermediate frames with different properties based on the frame set; and The second compositing unit (32) generates the composite frame by compositing the plurality of intermediate frames. The ultrasonic diagnostic device includes: The calculation unit (68) calculates an evaluation value based on at least one of the plurality of intermediate frames; and The control unit (40) changes the combination of the first transmission frequency and the second transmission frequency based on the evaluation value. The multiple intermediate frames include a summed image and an edge-emphasis image. The evaluation value is equivalent to the difference between the summed image and the edge-emphasized image.

2. The ultrasonic diagnostic device according to claim 1, characterized in that, The control unit (40) sets the first transmission focus depth and the second transmission focus depth based on the diagnostic depth range.

3. The ultrasonic diagnostic device according to claim 1, characterized in that, The first transmit / receive condition includes a first receive passband. The second transmit / receive condition includes a second receive passband that is narrower than the first receive passband.

4. The ultrasonic diagnostic device according to claim 1, characterized in that, The first transmit / receive condition includes a first beam deflection angle. The second transmit / receive condition includes a second beam deflection angle that is different from the first beam deflection angle.

5. The ultrasonic diagnostic device according to claim 1, characterized in that, The ultrasonic diagnostic device includes: An array of vibrating elements consists of multiple vibrating elements arranged along the principal and secondary directions. The first transmit / receive condition includes a first aperture size as the aperture size in the secondary direction. The second transmit / receive condition includes a second aperture size, which is an aperture size in the secondary direction and is different from the first aperture size.

6. The ultrasonic diagnostic device according to claim 1, characterized in that, The first compositing unit (28, 30) generates a summed image and an edge-emphasis image as the plurality of intermediate frames. The second synthesis unit (32) generates the synthesized frame by synthesizing the added image and the edge-emphasis image.

7. A control method for an ultrasonic diagnostic device, characterized in that, include: The process of generating a frame series involves repeatedly generating a transmitted signal and processing a received signal based on multiple cyclically set transmit and receive conditions. The process of generating multiple intermediate frames with different properties based on each frame set in the frame series; The process of generating a composite frame for forming an ultrasound image by synthesizing the plurality of intermediate frames according to each of the frame sets; The process of calculating the evaluation value based on at least one of the plurality of intermediate frames; The process of changing the combination of multiple transmission frequencies included in the multiple transmission and reception conditions based on the evaluation value. The multiple intermediate frames include a summed image and an edge-emphasis image. The evaluation value is equivalent to the difference between the summed image and the edge-emphasized image.

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