JP5190219B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasound diagnostic apparatus that captures and displays an ultrasound image. More specifically, the present invention relates to an ultrasonic diagnostic apparatus that obtains a compound scan image by synthesizing images formed with different frequency components.

  The ultrasound diagnostic apparatus converts the luminance of the acoustic hardness of the subject tissue into an image. Usually, a high-frequency electric signal of several MHz is applied to a plurality of transducers provided in the ultrasonic probe from a transmission unit. Electroacoustic conversion is performed by the vibrator, and an ultrasonic signal is transmitted to the subject. The ultrasonic signal is reflected at a location where the acoustic impedance derived from the hardness of the subject is different. The reflected echo signal is received by the transducer. The reception signal output from each transducer is amplified and phased, such as delay processing in consideration of the distance from the focal point to each transducer, is performed and is electrically focused. An ultrasonic beam is formed by adding the focused reception signal. The performance of the ultrasonic diagnostic apparatus is determined by the resolution of the ultrasonic beam.

The resolution is roughly classified into a distance resolution in the depth direction and an azimuth resolution in the azimuth direction. The distance resolution is improved as the pulse width of the ultrasonic pulse is reduced. The azimuth resolution is determined by the beam width of the ultrasonic beam.
In the electronic scanning ultrasonic diagnostic apparatus, the ultrasonic probe is configured by arranging a plurality of transducers one-dimensionally or two-dimensionally. In the one-dimensional array probe, the short axis direction is the longitudinal direction of the vibrator, and the long axis direction is the array direction of the vibrator and the electronic scanning direction. The azimuth resolution is divided into resolutions in two directions, a major axis direction and a minor axis direction. The resolution in the major axis direction is determined by the arrangement pitch of the transducers and the ultrasonic frequency.

Moreover, the speckle of a granular pattern exists in an ultrasonic diagnostic image. Speckle is not directly related to the structure in the subject. There are innumerable reflectors in the subject that are sufficiently smaller than the wavelength of ultrasonic waves. Speckle is an artifact generated by interference of waves scattered by countless reflectors in a subject.
The average particle size of the speckle depends on the frequency of the received signal and is smaller as the center frequency is higher. The average particle size of the speckle becomes smaller as the opening width of the ultrasonic probe is larger. As a method for reducing the manifestation of speckles, a frequency compound type ultrasonic diagnostic apparatus has been proposed (see, for example, [Patent Document 1]).

The frequency compound ultrasonic diagnostic apparatus divides a received signal into a plurality of band signals, independently detects each band signal, and superimposes the results. A band pass filter (BPF) is used for band division.
Since the shape of speckle is different in an ultrasonic image formed by band signals of different bands, speckle can be reduced by spatially adding these images. That is, by overlapping the interference conditions for each band, the speckles formed by the received signals in the respective bands can be canceled and the speckle noise can be made inconspicuous.

JP 2000-51210 A

  However, in the conventional frequency compound type ultrasonic diagnostic apparatus, speckle is reduced, but after the phasing process is performed with a certain phasing frequency, the band division process is performed, and the optimal phasing is performed for each band. Since phase processing is not performed, there is a problem that spatial resolution, particularly distance resolution, is degraded.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic diagnostic apparatus capable of reducing speckle noise and improving the image quality of an ultrasonic image.

In order to achieve the above-described object, the present invention provides an ultrasonic probe that transmits / receives ultrasonic waves to / from a subject, and image processing that forms an ultrasonic image based on a reception signal output from the ultrasonic probe. A phasing frequency setting means for setting a plurality of phasing frequencies, and a reception signal output from the ultrasonic probe. The received signal dividing means for dividing the set plurality of phasing frequency band signals, the phasing condition calculating section for calculating the phasing condition for each phasing frequency set by the phasing frequency setting means, Based on the phasing condition calculated by the phasing condition calculation unit, phasing processing means for phasing the plurality of band signals for each phasing frequency and outputting phasing data; and the phasing processing means From the phasing data output by A band signal acquisition means for acquiring a band signal of a number of center frequencies, and a band signal of a center frequency other than the band signal of the highest center frequency among the band signals of a plurality of center frequencies acquired by the band signal acquisition means. On the other hand, a filter processing means for performing a filter process for removing a signal having a predetermined amplitude or more, a band signal of the center frequency filtered by the filter processing means, and a band signal of the highest center frequency are added. And a band signal adding means for outputting an ultrasonic beam signal .

The ultrasonic diagnostic apparatus of the present invention sets a plurality of phasing frequencies (phase matching center frequencies), and divides a reception signal output from the ultrasonic probe into a plurality of set phasing frequency band signals. Then, the phasing condition is calculated for each phasing frequency, the phasing processing is performed on the band signal different for each phasing frequency based on the phasing condition, and the phasing data (ultrasound beam signal) is output.
The phasing condition is a condition for creating phasing data having a high spatial resolution for each phasing frequency. The phasing process is an amplitude weighting process or an aperture width determination process in the aperture direction. The phasing condition is information relating to parameters used for the phasing process, for example.

  In the present invention, since the ultrasonic diagnostic apparatus performs the phasing process using a unique phasing condition for each phasing frequency, it is possible to improve the spatial resolution and acquire a high-quality ultrasonic image. . In addition, since the speckle shape is different in an ultrasonic image formed by band signals in different bands, speckle can be reduced by spatially adding these images.

Also, a plurality of center frequency band signals are obtained from the phasing data, and a band signal having a center frequency other than the highest center frequency band signal among the plurality of center frequency band signals is greater than a predetermined amplitude. May be added to the filtered center frequency band signal and the highest center frequency band signal to output an ultrasonic beam signal.
In addition, the band signal having the highest center frequency is selected from the band signals having a plurality of center frequencies, the band signal having the selected center frequency is not filtered, and the band signals having other center frequencies are not subjected to filtering. Therefore, it is desirable to perform filtering.
It is desirable that the predetermined amplitude as the threshold value for the filter processing is about the amplitude of a signal indicating speckle.

  As a result, the ultrasonic diagnostic apparatus adds the band signals of a plurality of center frequencies for the signal corresponding to the speckle, and performs the filtering process on the signal corresponding to the structure of the subject and the target part. Since only the band signal of the center frequency with a high spatial resolution is added, the generation of speckle can be reduced, and the spatial resolution of the subject structure and target region can be improved as compared with the prior art.

  According to the present invention, it is possible to provide an ultrasonic diagnostic apparatus capable of reducing speckle noise and improving the image quality of an ultrasonic image.

  Hereinafter, preferred embodiments of an ultrasonic diagnostic apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, the same reference numerals are given to components having substantially the same functional configuration, and redundant description will be omitted.

(1. First embodiment)
(1-1. Configuration of ultrasonic diagnostic apparatus)
First, the configuration of the ultrasonic diagnostic apparatus 1 will be described with reference to FIGS. 1 and 2.

FIG. 1 is a configuration diagram of the ultrasonic diagnostic apparatus 1.
The ultrasonic diagnostic apparatus 1 includes an ultrasonic signal generator 22, an ultrasonic probe 3 including a plurality of transducers 2 that convert electrical signals into ultrasonic signals, and a transmission created by the ultrasonic signal generator 22. A transmission amplifier 4 that amplifies the signal to an amplitude sufficient to drive the vibrator 2, a transmission / reception separator 5 that switches a connection circuit between the transmission signal and the reception signal, and reception that amplifies the reception signal received by the vibrator 2. An amplifier 6, an A / D converter 7 that digitizes a received signal, and a phasing unit 21 are provided.

The phasing unit 21 includes a delay correction unit 8 for correcting a distance difference between the focus point and each transducer 2, a delay data calculation unit 9 for calculating delay data (focus data), and a phasing for each band. A phasing frequency setting unit 11 for setting a phasing frequency (phase matching center frequency) for performing phase processing, and various phasings capable of forming phasing data (ultrasonic beam signal) having the highest spatial resolution for each band. A phasing condition calculation unit 12 that calculates conditions, a phasing processing unit 14 that performs a phasing process on the received signal using the conditions calculated by the phasing condition calculation unit 12, and an addition process of the phasing data of each channel And a channel adder 15 for performing the operation.
The number of channels indicates the number of channels (aperture width) used to form one ultrasonic beam. Each channel is constituted by one or a plurality of vibrators 2.

The delay data calculation unit 9 includes a memory 10. The memory 10 stores delay data calculated by the delay data calculator 9 and delay data obtained in advance by an external calculation process.
The phasing condition calculation unit 12 includes a memory 13. The memory 13 stores the phasing condition calculated by the phasing condition calculation unit 12 and the phasing condition obtained in advance by an external calculation process.

  The ultrasonic echo signal reflected in the subject is received by the transducer 2 of the ultrasonic probe 3. The received signal passes through the transmission / reception separation circuit 5 that is switch-connected to the reception circuit, passes through the reception amplification unit 6, and is digitized by the A / D converter 7. The digitized received signal is subjected to phasing processing by the phasing unit 21. The phasing unit 21 performs phasing processing for each channel and each phasing frequency.

  The ultrasonic diagnostic apparatus 1 also adds a band signal acquisition unit 16 that acquires a plurality of band signals from the phasing data output from the channel addition unit 15 and a plurality of band signals acquired by the band signal acquisition unit 16. And a band signal adding unit 17 that performs the same.

  The ultrasonic diagnostic apparatus 1 also performs a signal processing unit 18 that performs signal processing for image configuration on the ultrasonic beam signal output from the band signal addition unit 17 and a DSC that performs display control of the ultrasonic image. (Digital Scan Converter) 19 and a monitor 20 for displaying an ultrasonic image.

FIG. 2 is a schematic perspective view of the ultrasonic probe 3.
The ultrasonic probe 3 includes an acoustic lens 31, a matching layer 32, a plurality of transducers 2, and a backing layer 33. The acoustic lens 31 converges the ultrasonic beam in the short axis direction. The vibrator 2 is formed of a piezoelectric material that performs electrical / acoustic conversion. The matching layer 32 matches the acoustic impedance between the transducer 2 and the subject and improves the transmission efficiency of ultrasonic waves. The backing layer 33 performs mechanical damping of the vibrator 2.

(1-2. Operation of the phasing unit 21)
Next, the operation of the phasing unit 21 will be described with reference to FIG.
FIG. 3 is a diagram showing a flow of operation of the phasing unit 21.

  A reflected echo signal from the target region 41 in the subject is received by each channel of the transducer 2. The delay amount correction unit 8 performs a delay process according to the distance difference between the focus point and each channel of the vibrator 2. The phasing processing unit 14 performs an amplitude weighting process and an aperture width determination process for each channel and each phasing frequency on the reception signal delayed by the delay amount correction unit 8. The channel adder 15 adds the phasing data formed for each channel.

  The phasing frequency setting unit 11 selects and determines a plurality of phasing frequencies based on the number of bands in which frequency compound processing is performed.

  The delay amount correction unit 8 performs delay processing using the delay data 42 independent for each channel and each phasing frequency. The delay data 42 is calculated by the delay data calculation unit 9 or read from the memory 10 based on the focus point and the phasing frequency.

  The phasing processing unit 14 performs phasing processing using independent phasing parameters 43 for each channel and each phasing frequency. The phasing parameter 43 is data relating to an amplitude weighting coefficient, an aperture width, and the like that enable optimum phasing according to the phasing frequency. The phasing parameter 43 is calculated by the phasing condition calculation unit 12 based on the phasing frequency or read from the memory 13.

  As shown in FIG. 3, the phasing processing unit 14 may be arranged after the delay amount correcting unit 8, or the delay amount correcting unit 8 may be arranged after the phasing processing unit 14.

(1-2-1. Time division processing)
FIG. 4 is a diagram illustrating a flow of operation of the phasing unit 21 when the time division processing is used.
The reception signal output from the transducer 2 of the ultrasonic probe 3 is time-division processed by the number of phasing frequencies for each channel. In FIG. 4, the received signal is time-divided into three band signals having phasing frequencies f1, f2, and f3, respectively.

The delay amount correction unit 8 performs delay processing on the three band signals of each channel, using the delay data 42 independent for each channel and each phasing frequency. The delay amount correction unit 8 performs delay processing on the channels ch1, ch2,..., ChN using the delay data 42-1 (d1), 42-2 (d2),..., 42-N (dN), respectively. .
Specifically, the delay amount correcting unit 8 performs delay processing on the band signals of the phasing frequencies f1, f2, and f3 of the channel chN using the delay data dN _f1 , dN _f2 , and dN _f3 , respectively.

The phasing processing unit 14 performs phasing processing on the three band signals of each channel using the phasing parameter 43 independent for each channel and each phasing frequency. The phasing processing unit 14 uses the phasing parameters 43-1 (e1), 43-2 (e2),..., 43-N (eN) for the channels ch1, ch2,. I do.
Specifically, the phasing processing unit 14 performs phasing processing on the band signals of the phasing frequencies f1, f2, and f3 of the channel chN using the phasing parameters eN _f1 , eN _f2 , and eN _f3 , respectively. Do.

  Thus, by performing the time division processing, it is not necessary to provide a circuit for each phasing frequency, so that the circuit configuration and the circuit scale can be reduced.

(1-2-2. Parallel processing)
FIG. 5 is a diagram showing a flow of operation of the phasing unit 21 when parallel processing is used.
A separate circuit is provided for each phasing frequency. The delay amount correction unit 8 includes a delay circuit based on the delay data 42 for each channel and each phasing frequency. The phasing processing unit 14 includes a phasing circuit based on the phasing parameter 43 for each channel and each phasing frequency. The reception signal output from the transducer 2 of the ultrasonic probe 3 is processed in parallel for each channel and each phasing frequency. In FIG. 5, the received signal is divided into three band signals having phasing frequencies f1, f2, and f3, respectively, and processed in parallel.

Specifically, the received signal from channel chN is divided into three band signals having phasing frequencies f1, f2, and f3. Three delay processes are performed in parallel using the delay data dN _f1 , dN _f2 , and dN _f3 for the delay amount correction unit 8 and the band signals of the phasing frequencies f1, f2, and f3 of the channel chN, respectively. The phasing processing unit 14 performs three phasing processes in parallel for the band signals of the phasing frequencies f1, f2, and f3 of the channel chN using the phasing parameters eN _f1 , eN _f2 , and eN _f3 , respectively. Do it.

  In this way, by providing an independent circuit for each phasing frequency, the data bandwidth does not narrow and the amount of information held in the phasing data does not decrease. can do.

(1-3. Phasing parameter 43)
Next, the relationship between the phasing parameter 43 (aperture width and amplitude weighting coefficient) and the ultrasonic beam will be described with reference to FIGS.

(1-3-1. Opening width)
FIG. 6 is a diagram showing the relationship between the aperture width and the ultrasonic beam. The vertical axis represents intensity, and the horizontal axis represents the azimuth direction position.
An ultrasonic beam 51 is an ultrasonic beam formed with an opening width of 100 ch. The ultrasonic beam 61 is an ultrasonic beam formed with an opening width of 50 ch.

  The main lobe width 52 of the ultrasonic beam 51 is narrower than the main lobe width 62 of the ultrasonic beam 61. Further, the grating level 53 of the ultrasonic beam 51 is lower than the grating level 63 of the ultrasonic beam 61. In addition, the dynamic range 54 of the ultrasonic beam 51 is larger than the dynamic range 64 of the ultrasonic beam 61. Therefore, by increasing the aperture width, it is possible to improve spatial resolution and acoustic SN ratio.

(1-3-2. Amplitude weighting coefficient)
7 and 8 are diagrams showing the relationship between the amplitude weighting coefficient and the ultrasonic beam. The vertical axis represents intensity, and the horizontal axis represents the azimuth direction position.
The ultrasonic beams 71 and 91 indicate ultrasonic beams formed by multiplying the amplitude weighting coefficient in the aperture direction. The ultrasonic beams 81 and 101 are ultrasonic beams formed without using an amplitude weighting coefficient in the aperture direction.

  Referring to FIG. 7, the main lobe width 72 of the ultrasonic beam 71 is narrower than the main lobe width 82 of the ultrasonic beam 81. In addition, the dynamic range 74 of the ultrasonic beam 71 is larger than the dynamic range 84 of the ultrasonic beam 81. Referring to FIG. 8, the grating level 93 of the ultrasonic beam 91 is lower than the grating level of the ultrasonic beam 101. The dynamic range 94 of the ultrasonic beam 91 is larger than the dynamic range of the ultrasonic beam 101. Therefore, the spatial resolution and the acoustic SN ratio can be improved by multiplying the amplitude weighting coefficient in the aperture direction.

(1-4. Effects of the first embodiment)
As described above, the ultrasonic diagnostic apparatus according to the first embodiment sets a plurality of phasing frequencies, divides a received signal into a plurality of band signals, and uses a unique phasing parameter for each phasing frequency. Phasing process. Thus, by performing the phasing process optimized for each phasing frequency, it is possible to improve the spatial resolution and obtain a high-quality ultrasonic image.
Moreover, since the speckle shape is different in an ultrasonic image formed by signals in different bands, speckle can be reduced by spatially adding these images.

(2. Second Embodiment)
Next, a second embodiment will be described with reference to FIGS.
FIG. 9 is a configuration diagram of the band signal acquisition unit 16 and the band signal addition unit 17a according to the second embodiment.
FIG. 10 is a diagram illustrating band division of the phasing data 112.
FIG. 11 is a diagram illustrating the provision of amplitude weighting coefficients.

  4 and 5, the ultrasonic diagnostic apparatus 1 sets the optimum phasing parameter for each of the three phasing frequencies f1, f2, and f3 in the phasing unit 21 and performs the phasing process. At each phasing frequency, the shape of each ultrasonic beam signal is different, and the spatial resolution of the ultrasonic image formed by each ultrasonic beam signal is also different. If an ultrasound image is constructed using each ultrasound beam signal as it is, the spatial resolution of the ultrasound image will be averaged.

  The phasing data output from the channel addition unit 15 is input to the band signal acquisition unit 16. The band signal acquisition unit 16 again sets a plurality of center frequencies and divides the phasing data into a plurality of band signals. The setting of the center frequency and the number of bands in the band signal acquisition unit 16 may be the same as or different from the phasing frequency and the number of bands in the phasing frequency setting unit 11 of the phasing unit 21. For example, in FIGS. 9 and 10, the phasing data 112 is divided into band signals 113-1, 113-2, and 113-3 having three center frequencies f1, f2, and f3.

  The band signal adding unit 17a gives an independent amplitude weighting coefficient for each band signal. The band signal adding unit 17a multiplies the band signals 113-1, 113-2, and 113-3 by the amplitude weighting coefficients 111-1 (w1), 111-2 (w2), and 111-3 (w3), respectively, and adds them. Process.

  It is desirable to increase the amplitude weighting coefficient 111 for the band signal 113 with a high spatial resolution and to decrease the amplitude weighting coefficient for the band signal 113 with a low spatial resolution. In general, the higher the center frequency, the higher the spatial resolution. As shown in FIG. 11, when the magnitude relationship between the three center frequencies is f1 <f2 <f3, it is desirable that the magnitude relationship between the amplitude weighting coefficients is w1 <w2 <w3.

  As described above, the ultrasonic diagnostic apparatus according to the second embodiment forms an ultrasonic beam by preferentially using the band signal having the highest spatial resolution among the band signals having a plurality of center frequencies. Therefore, the spatial resolution of the ultrasonic image can be improved. In addition, since the ultrasonic beam is formed by adding the band signals having a plurality of center frequencies, speckle generation can be reduced.

In general, the higher the center frequency, the higher the spatial resolution. Therefore, it is desirable to preferentially use a band signal having a high center frequency to form an ultrasonic beam.
When the phasing frequency and the number of bands in the phasing frequency setting unit 11 of the phasing unit 21 are the same as the center frequency and the number of bands in the band signal acquisition unit 16, it is output from the channel addition unit 15. There is no need to divide the phasing data again.

(3. Third embodiment)
Next, a third embodiment will be described with reference to FIGS.
In the second embodiment, it has been described that an ultrasonic beam is formed using a band signal having a center frequency with the highest spatial resolution preferentially. In the third embodiment, for a signal indicating a speckle part, an ultrasonic beam is formed by adding a band signal of a plurality of center frequencies. An ultrasonic beam is formed using only a band signal having a high resolution and a center frequency.

  FIG. 12 is a diagram showing the relationship between the ultrasonic image 122 and the band signals 123-1, 123-2, 123-3 (no filter processing). The vertical axis represents the depth. The horizontal axis of the ultrasonic image 122 indicates the azimuth direction position. The horizontal axis of the band signal 123 indicates luminance (amplitude).

  The ultrasonic image 122 is an ultrasonic image formed by adding the band signals 123-1, 123-2, and 123-3 as they are. The center frequencies of the band signals 123-1, 123-2, and 123-3 are f1, f2, and f3 (f1 <f2 <f3), respectively.

  The distance 127-1 (Δs1) is the difference between the peak value and the minimum value of the two waveform peaks 125-1 and 126-1 of the band signal 123-1 near the depth 124. The distance 127-2 (Δs2) is the difference between the peak value and the minimum value of the two waveform peaks 125-2 and 126-2 of the band signal 123-2 in the vicinity of the depth 124. The distance 127-3 (Δs1) is the difference between the peak value and the minimum value of the two waveform peaks 125-3 and 126-3 of the band signal 123-3 near the depth 124. The distance 127-1 (Δs1), the distance 127-2 (Δs2), and the distance 127-3 (Δs3) are luminance differences between the peak position and the boundary position, and correspond to distance resolution.

  In general, the higher the center frequency, the higher the spatial resolution. Therefore, the distance 127-1 (Δs 1) <the distance 127-2 (Δs 2) <the distance 127-3 (Δs 3). If the ultrasonic signals 122 are formed by adding the band signals 123-1, 123-2, and 123-3 as they are, the spatial resolution is averaged. For example, the waveform peak 125 and the image 128 corresponding to the waveform peak 126 are displayed as one area, and cannot be identified as two actual areas.

FIG. 13 is a configuration diagram of the band signal acquisition unit 16 and the band signal addition unit 17b according to the third embodiment.
The operation of the band signal acquisition unit 16 is the same as that of the second embodiment. The band signal addition unit 17b performs addition processing after performing filter processing on band signals of other center frequencies using the filter 121, except for one selected band signal.

FIG. 14 is a diagram illustrating an aspect of the filter 121. The vertical axis represents the depth. The horizontal axis represents luminance (amplitude).
A region 141 is a signal region having an amplitude smaller than the threshold value 140. A region 141 is a signal region corresponding to speckle. A region 142 is a signal region having an amplitude larger than the threshold value 140. The region 142 is a signal region corresponding to the structure of the subject and the target site. The filter 121 removes a signal component having an amplitude larger than the threshold value 140.
The threshold 140 is preferably larger than the amplitude of the signal indicating the speckle assumed and smaller than the amplitude of the signal indicating the structure of the subject and the target region. A plurality of types of filters may be prepared in advance, or the threshold value 140 may be selectable by the examiner.

  It is desirable that the band signal 123 with high spatial resolution is not subjected to filter processing, and the band signal 123 with low spatial resolution is subjected to filter processing with the filter 121. In general, the higher the center frequency, the higher the spatial resolution. Therefore, the three band signals 123-1, 123-2, and 123-3 shown in FIG. 12 are filtered for the band signal 123-3 having the highest center frequency. Instead, it is desirable to perform the filter processing by the filter 121 on the band signals 123-1 and 123-2 other than the band signal 123-3.

  FIG. 15 is a diagram illustrating the relationship between the ultrasonic image 132, the band signal 133-1, the band signal 133-2, and the band signal 133-3 (with filter processing). The vertical axis represents the depth. The horizontal axis of the ultrasonic image 132 indicates the azimuth direction position. The horizontal axis of the band signal 133 indicates luminance (amplitude).

Band signals 133-1 and 133-2 are band signals obtained by performing filter processing on the band signals 123-1 and 123-2 in FIG. The band signal 133-3 is the same band signal as the band signal 123-3 of FIG.
In the band signal 133-1, a signal component having an amplitude exceeding the threshold value 140-1 is removed by the filter 121. In the band signal 133-2, a signal component having an amplitude exceeding the threshold value 140-2 is removed by the filter 121.

  If these band signals 133-1, 133-2, and 133-3 are added to form an ultrasound image 132, the band signal 133 is not averaged with respect to the structure of the subject and the spatial resolution of the target region. -3 spatial resolution is reflected. For example, in the vicinity of the depth 134, the image 138 and the image 139 corresponding to the waveform peak 135-3 and the waveform peak 136-3 are displayed so as to be identifiable as two regions.

  Band signals 133-1, 133-2, and 133-3 all include signal components having amplitudes less than threshold values 140-1, 140-2, and 140-3, that is, signal components corresponding to speckles. Speckle generation can be reduced by adding the signal components of these areas 140-1, 140-2, and 140-3.

  As described above, the ultrasonic diagnostic apparatus according to the third embodiment adds a band signal of a plurality of center frequencies for signals corresponding to speckles, and signals corresponding to the structure of the subject and the target region. Since only the band signal of the center frequency with the highest spatial resolution is added by filtering, the generation of speckle can be reduced, and the spatial resolution can be improved for the structure and target portion of the subject. .

(4. Other)
The preferred embodiments of the ultrasonic diagnostic apparatus according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

Configuration diagram of the ultrasonic diagnostic apparatus 1 Schematic perspective view of the ultrasound probe 3 The figure which shows the flow of operation | movement of the phasing part 21. The figure which shows the flow of operation | movement of the phasing part 21 in the case of using a time division process. The figure which shows the flow of operation | movement of the phasing part 21 in the case of using parallel processing. Diagram showing the relationship between aperture width and ultrasonic beam The figure which shows the relation between the amplitude weighting coefficient and the ultrasonic beam The figure which shows the relation between the amplitude weighting coefficient and the ultrasonic beam Configuration of Band Signal Acquisition Unit 16 and Band Signal Addition Unit 17a (Second Embodiment) The figure which shows the zone | band division | segmentation of the phasing data 112 Diagram showing the assignment of amplitude weighting factors It is a figure which shows the relationship between the ultrasonic image 122 and the band signal 123 (no filter process) Configuration of Band Signal Acquisition Unit 16 and Band Signal Addition Unit 17b (Third Embodiment) The figure which shows the one aspect | mode of the filter 121 It is a figure which shows the relationship between the ultrasonic image 132 and the zone | band signal 133 (with a filter process).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ......... Ultrasonic diagnostic apparatus 2 ......... Transducer 3 ......... Ultrasonic probe 4 ......... Transmission amplifier 5 ......... Transmission / reception separator 6 ......... Reception amplifier 7 ......... A / D conversion 8 ......... Delay amount correction unit 9 ...... Delay data calculation unit 10 ...... Memory (delay data)
11 ......... Phaseing frequency 12 ......... Phaseing condition calculation unit 13 ......... Memory (phasing condition)
14 ......... Phase processing unit 15 ......... Channel addition unit 16 ......... Band signal acquisition unit 17, 17a, 17b ......... Band signal addition unit 18 ......... Signal processing unit 19 ......... DSC
20 ......... Monitor 21 ......... Phase control unit 22 ......... Ultrasonic signal generator 41 ......... Target region 42 ......... Delay data 43 ......... Phase control parameters 51, 61, 71, 81, 91, 101 ......... Ultrasonic beam 52, 62, 72, 82 ......... Main lobe width 53, 63, 93 ......... Grating level 54, 64, 74, 84, 94 ......... Dynamic range 111-1, 111- 2, 111-3... Amplitude weighting coefficient 112... Phased data 113-1, 113-2, 13-3 ... Band signal 121 ... Filters 122 and 132 ... Ultrasonic image 123 1, 123-2, 123-3, 133-3 ... Band signal (no filtering)
133-1, 133-2... Band signal (with filter processing)
140, 140-1, 140-2, 140-3... Threshold value

Claims (3)

An ultrasonic probe that transmits / receives ultrasonic waves to / from a subject, an image processing unit that configures an ultrasonic image based on a reception signal output from the ultrasonic probe, and a display unit that displays the ultrasonic image In an ultrasonic diagnostic apparatus comprising:
Phasing frequency setting means for setting a plurality of phasing frequencies;
A reception signal dividing means for dividing the reception signal output from the ultrasonic probe into a plurality of band signals of the set phasing frequencies;
A phasing condition calculation unit for calculating a phasing condition for each phasing frequency set by the phasing frequency setting means;
Based on the phasing condition calculated by the phasing condition calculation unit, phasing processing means for phasing the plurality of band signals for each phasing frequency and outputting phasing data;
Band signal acquisition means for acquiring band signals of a plurality of center frequencies from the phasing data output by the phasing processing means;
A filter that performs a filter process for removing a signal having a predetermined amplitude or more with respect to a band signal having a center frequency other than the band signal having the highest center frequency among the band signals having a plurality of center frequencies acquired by the band signal acquisition unit. Processing means;
A band signal adding means for adding the band signal of the center frequency filtered by the filter processing means and the band signal of the highest center frequency to output an ultrasonic beam signal;
An ultrasonic diagnostic apparatus comprising: The filter processing means includes
The band signal having the highest center frequency is selected from among the plurality of band signals of the center frequency acquired by the band signal acquisition means, and the filter processing is not performed on the band signal of the selected center frequency, and the others The ultrasonic diagnostic apparatus according to claim 1, wherein the filtering process is performed on a band signal having a center frequency of . Said predetermined amplitude as a threshold for filtering ultrasound diagnostic apparatus according to claim 1 or claim 2, characterized in that an amplitude of about signal indicating speckle.

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