JP5547010B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus that displays a diagnostic image of an internal tissue of a subject.

  Conventionally, an ultrasonic diagnostic apparatus that displays an image of an internal tissue of a human body transmits an ultrasonic beam toward the inside of the human body and receives a reflected ultrasonic wave reflected inside the human body to obtain a reception signal. A tomographic image whose luminance is modulated based on the amplitude is displayed two-dimensionally.

  However, the internal tissue of the human body has characteristics that the attenuation characteristics of the ultrasonic waves differ depending on the medium to be configured, and that the attenuation increases as the frequency increases.

  Accordingly, ultrasonic waves to be transmitted are generally used in a frequency range of 1 to 15 MHz, and a very high frequency cannot be used. In addition, the waveform of the signal (echo signal) that is transmitted from the ultrasonic pulse and reflected by the internal tissue is strongly attenuated as the frequency is higher, so that the waveform of the received signal is a mountain-shaped waveform with a wide distortion base. For this reason, there is a limit to increase the resolution by narrowing the pulse width of the ultrasonic pulse, and even if the received signal reflected by the internal tissue is amplified and displayed as it is, the outline of the internal tissue becomes unclear. Therefore, it is common to display an image by applying edge enhancement processing to the received signal.

  Here, there is known an ultrasonic diagnostic apparatus that emphasizes a contour of a tissue and displays an image (see, for example, Patent Document 1).

  FIG. 1 is a block diagram showing a configuration of a conventional ultrasonic diagnostic apparatus.

  An ultrasonic diagnostic apparatus 1 shown in FIG. 1 transmits an ultrasonic beam into a subject and a probe 10 in which a plurality of transducers that receive reflected ultrasonic waves reflected in the subject are arranged, and the probe 10. A transmission / reception circuit 11 having a pulse generation circuit 11a for applying a pulse voltage to each transducer (not shown) and a reception circuit 11b for obtaining a reception signal from the signal received by each transducer, and beam forming the received signal. Beam forming (BF) circuit 12, bandpass filter (BPF) 13 for removing unnecessary signals from the received signal for each ultrasonic beam, and detection circuit for removing high-frequency components from the output signal of bandpass filter 13 ( DET) 14, an amplifier (LOG) 15 for logarithmically amplifying a tomographic image signal from which high-frequency components have been removed by the detection circuit 14, and logarithmically amplified From the edge emphasis processing unit (EE) 16 that emphasizes the reception signal for each acoustic beam so that the rising and falling portions of the amplitude are increased, and the low frequency component formed by the reception signal for each ultrasonic beam, The contour detection unit 17 that detects a region having a large change in the low frequency component as a contour portion, and the region detected as the contour portion by the contour detection unit 17 employs a reception signal whose amplitude is enhanced by the edge enhancement processing unit 16. In addition, the signal generation unit 18 that generates a reception signal in which only the contour portion is emphasized by adopting the reception signal before being subjected to the enhancement by the edge enhancement processing unit 16 in the region other than the region detected as the contour portion; And a display unit 19 for displaying a tomographic image with luminance based on the received signal in which only the contour portion is emphasized by the signal generation unit 18.

  The probe 10 and the transmission / reception circuit 11 are connected to each other, the output of the transmission / reception circuit 11 is input to the bandpass filter 13, the output of the bandpass filter 13 is input to the detection circuit 14, and the output of the detection circuit 14 is an amplifier. 15 and the contour detection unit 17, the output of the amplifier 15 is input to the edge enhancement processing unit 16 and the signal generation unit 18, and the output of the contour detection unit 17 is input to the signal generation unit 18 and the signal generation unit 18. Is input to the display unit 19.

  FIG. 2 is a block diagram of the edge enhancement processing unit shown in FIG.

  The edge enhancement processing unit 16 shown in FIG. 2 includes multiplication circuits 16a and 16b, a delay circuit 16c, and an addition circuit 16d.

  One of the signals F (x) input to the edge enhancement processing unit 16 is multiplied by a coefficient (1 + α) by a multiplication circuit 16a to become a signal (1 + α) F (x), and the other is a delay circuit for a time τ. The signal (−α) F (x + τ) is delayed and multiplied by the coefficient (−α) in the multiplication circuit 16b. These two signals are further added by the adder circuit 16d, and the rising portion and the falling portion of the signal F (x) are emphasized to increase the amplitude of the signal (1 + α) F (x) + (− α ) F (x + τ) and output.

Japanese Patent No. 4105452

  In the edge enhancement processing unit 16 shown in FIG. 2, the portion immediately after the edge is enhanced in both the rising edge and the falling edge of the signal. Immediately after the rising edge, that is, after the signal level has shifted from a low level to a high level, the signal level of the portion is emphasized in the direction of increasing by the edge enhancement process, so that one end of the tissue that is brightly shown as an image It is brighter and emphasized and displayed clearly. However, even if the edge enhancement process is performed immediately after the falling edge, that is, after the signal level has shifted from a high level to a low level, the signal level is enhanced in a decreasing direction, and is brightly displayed as an image. At the other end of the tissue, the emphasis effect of being brighter and clearer is less likely to appear.

  An object of the present invention is to provide an ultrasonic diagnostic apparatus that solves the above-described problems and displays an easy-to-see diagnostic image in which edges corresponding to both the rising edge and the falling edge of the tissue are clearly displayed. To do.

An ultrasonic diagnostic apparatus of the present invention that achieves the above object transmits an ultrasonic beam into a subject and reflects the reflected ultrasonic wave that has been reflected back within the subject. An ultrasonic diagnostic apparatus that displays a tomographic image of a tissue in an ultrasonic transmission / reception area with brightness,
The rising edge of the received signal by adding a signal subjected to processing of multiplying a positive coefficient to the signal level of the received signal and processing the signal subjected multiplying delay and negative coefficient with respect to the received signal is emphasized A rising edge emphasis processing unit that generates a rising edge emphasis signal, a signal obtained by multiplying the received signal by a delay and a positive coefficient, and a signal obtained by multiplying the signal level of the received signal by a negative coefficient and having an edge enhancement signal generation unit and a falling edge enhancement processing unit for generating a falling edge enhancement signal falling edge is emphasized in the received signal by adding an.

  In the ultrasonic diagnostic apparatus of the present invention, the signal portion immediately after the rising edge of the reception signal is amplified by the rising edge enhancement processing unit, and the signal portion immediately before the falling edge of the reception signal is amplified by the falling edge enhancement processing unit. The For this reason, an easy-to-see diagnostic image in which ends corresponding to both the rising edge and the falling edge of the tissue are clearly displayed is displayed.

Further, according to the ultrasonic diagnostic apparatus of the present invention, it is possible to perform enhancement processing symmetrical in the time axis direction with a simple configuration with respect to the rising edge and the falling edge.

In the ultrasonic diagnostic apparatus of the present invention, the edge enhancement signal generation unit switches between the output of the rising edge enhancement processing unit and the output of the falling edge enhancement processing unit, so that the low frequency component of the reception signal is changed. For the first signal portion in which the difference between the signal level of the local minimum point when the local maximum point and the local minimum point are obtained and the signal level of the local maximum point next to the local minimum point is greater than a predetermined threshold, the rising edge emphasis signal is used. There is employed, the value and the next value and the difference is a predetermined threshold value greater than the second signal portion the falling edge enhancement signal is employed edge enhancement signal for the minimum point of the maximum point of the maximum point It is preferable to have an edge enhancement signal switching unit that generates

  The rising edge emphasis signal is adopted for the first signal portion obtained from the maximum point and the minimum point of the low frequency component of the received signal, and the falling edge emphasis signal is adopted for the second signal portion. A diagnostic image in which the contour is clearly displayed is displayed for both the corresponding contour portion and the contour portion corresponding to the falling edge.

  In the ultrasonic diagnostic apparatus of the present invention, the edge enhancement signal generation unit adds the output of the rising edge enhancement processing unit and the output of the falling edge enhancement processing unit to each other, whereby the rising edge enhancement signal is added. And an edge enhancement signal adding unit that generates an edge enhancement signal to which the falling edge enhancement signal is added.

  A simple configuration in which the output of the rising edge enhancement processing unit and the output of the falling edge enhancement processing unit are added to each other, and a diagnostic image is displayed in which edges corresponding to both the rising edge and the falling edge are clearly displayed. The

  In the ultrasonic diagnostic apparatus of the present invention, the edge enhancement signal is relatively strongly amplified for the first signal portion and the second signal portion of the received signal, and the edge of the received signal is For the third signal portion excluding the first signal portion and the second signal portion, the received signal before being input to the edge enhancement signal generation unit is relatively strongly amplified, and this received signal and this It is preferable to have a signal generation unit that adds edge enhancement signals to each other.

  The contrast of the edge portion can also be adjusted according to the user's preference by using a configuration in which signals obtained by relatively strongly amplifying the edge emphasis signal or relatively strongly amplifying the reception signal are added together.

  As described above, according to the present invention, an ultrasonic diagnostic apparatus is realized in which an easy-to-see diagnostic image in which ends corresponding to both the rising edge and the falling edge of the tissue are clearly displayed is displayed.

It is a block diagram which shows the structure of the conventional ultrasonic diagnostic apparatus. FIG. 2 is a block diagram of an edge enhancement processing unit shown in FIG. 1. 1 is a block diagram illustrating a configuration of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. It is a block diagram which shows the structure of the detection circuit shown in FIG. It is a block diagram which shows the structure of the outline detection part shown in FIG. It is a block diagram which shows the structure of the rising edge emphasis processing part and falling edge emphasis processing part which are shown in FIG. It is a figure which shows the input waveform and output waveform of a rising edge emphasis processing part and a falling edge emphasis processing part. It is a figure explaining the signal generation by the signal generation part 38. FIG. It is the figure which illustrated the waveform of the received signal in the ultrasonic diagnosing device shown in FIG. It is a figure which shows the image by which the outline part was emphasized and the luminance display was carried out in the ultrasonic diagnosing device of this embodiment. It is the figure which showed the luminance display part of the image shown in FIG. 10 in black. It is an image of a comparative example in which the falling edge is not emphasized. It is the figure which showed the luminance display part of the image shown in FIG. 12 in black. It is a block diagram which shows the structure of the ultrasonic diagnosing device of 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 3 is a block diagram showing the configuration of the ultrasonic diagnostic apparatus according to the first embodiment of the present invention.

  3 includes a probe 30, a transmission / reception circuit 31, a beam forming (BF) circuit 32, a band pass filter (BPF) 33, a detection circuit (DET) 34, and an amplifier (LOG). ) 35, an edge enhancement processing unit (EE) 36, a contour detection unit 37, a signal generation unit 38, and a display unit 39.

  The probe 30 has a plurality of transducers (not shown) arranged to transmit an ultrasonic beam into the subject and receive reflected ultrasonic waves reflected within the subject. The transmission / reception circuit 31 includes a pulse generation circuit 31a and a reception circuit 31b. The pulse generation circuit 31a applies a pulse voltage to each transducer of the probe 30, and the reception circuit 31b receives a signal received by each transducer. Get a signal. A beam forming (BF) circuit 32 performs beam forming on the received signal. The band pass filter (BPF) 33 removes unnecessary signals from the reception signal for each ultrasonic beam. The detection circuit (DET) 34 removes high frequency components from the output signal of the bandpass filter 33. The internal configuration of the detection circuit 34 will be described later. The amplifier (LOG) 35 logarithmically amplifies the tomographic image signal from which the high-frequency component has been removed by the detection circuit 34. The edge enhancement processing unit (EE) 36 enhances the received signal for each logarithmically amplified ultrasonic beam so that each of the rising edge portion and the falling edge portion becomes larger. A processing unit (LENH) 361 and a falling edge enhancement processing unit (RENH) 362 are provided. The rising edge emphasis processing unit 361 generates a rising edge emphasis signal in which the rising edge is emphasized by amplifying the signal portion immediately after the rising edge of the signal. Further, the falling edge enhancement processing unit 362 generates a falling edge enhancement signal in which the falling edge is emphasized by amplifying the signal portion immediately before the falling edge of the signal. Details of the rising edge enhancement processing unit 361 and the falling edge enhancement processing unit 362 will be described later. The contour detection unit 37 detects, from the low frequency component formed by the received signal for each ultrasonic beam, an area where the change in the low frequency component is large as a contour portion. The internal configuration of the contour detection unit 37 will be described later. The signal generation unit 38 employs a reception signal whose amplitude is enhanced by the edge enhancement processing unit 36 for the region detected as the contour part by the contour detection unit 37, and the region other than the region detected as the contour part is an edge. By using the reception signal before being emphasized by the enhancement processing unit 36, a reception signal in which only the contour portion is enhanced is generated. The signal generation unit 38 includes an edge enhancement signal switching unit 38a, multiplication circuits 38b and 38c, an addition circuit 38d, and a lookup table (hereinafter referred to as “LUT”) 38e. The display unit 39 displays a tomographic image with luminance based on the received signal in which only the contour portion is emphasized by the signal generation unit 38.

  The probe 30 and the transmission / reception circuit 31 are connected to each other, the output of the transmission / reception circuit 31 is input to the bandpass filter 33 via the beam forming circuit 32, and the output of the bandpass filter 33 is input to the detection circuit 34. The output of the detection circuit 34 is input to the amplifier 35 and the contour detection unit 37, the output of the amplifier 35 is input to the edge enhancement processing unit 36 and the signal generation unit 38, and the output of the contour detection unit 37 is the signal generation unit 38. And the output of the signal generation unit 38 is input to the display unit 39.

  Here, the combination of the edge enhancement processing unit 36 and the signal generation unit 38 corresponds to an example of the edge enhancement signal generation unit according to the present invention.

  FIG. 4 is a block diagram showing a configuration of the detection circuit shown in FIG.

  The detection circuit 34 shown in FIG. 4 is a circuit that performs quadrature detection of a received signal, and includes multiplication circuits 341 and 345, low-pass filters (LPF) 342 and 346, decimators (DEC) 343 and 347, and a square processing unit (SQUA). 344, 348 and a square root processing unit (SQRT) 349. In the detection circuit 34, an I signal obtained by multiplying the input received signal by the cosine signal by the multiplication circuit 341 and a Q signal obtained by multiplying the reception signal by the sine signal by the multiplication circuit 345 are generated. Each of the I signal and the Q signal is subjected to processing by the low-pass filters 342 and 346 and the decimators 343 and 347, and detection is performed by obtaining a square average by the square processing units 344 and 348 and the square root processing unit 349.

  FIG. 5 is a block diagram illustrating a configuration of the contour detection unit illustrated in FIG. 3.

  The contour detection unit 37 shown in FIG. 5 includes a low-level, high-frequency speckle component (for example, reflected by a soft wall of human body tissue and interferes with each other, and included in a reception signal for each ultrasonic beam, The signal that has been weakened) is removed, only the low-frequency component at high level is extracted, and the region where the change in the extracted low-frequency component is large is detected as the contour part of the human tissue. The low-frequency component of the received signal The maximum and minimum points are obtained from the point where the polarity of the difference between adjacent amplitudes is reversed, for example, and the region where the absolute value of the signal level (voltage etc.) of the difference between the maximum and minimum points is large is used as the contour portion. To detect.

  The contour detection unit 37 includes a low-pass filter (LPF) 371, an amplifier (LOG) 372, a Sensitivity Time Control (STC) 373, and a detection unit (ED) 374. The low-pass filter 371 detects a low-frequency component of the detection output of the reception signal for each ultrasonic beam, the Sensitivity Time Control 373 corrects the attenuation of the reception signal according to the distance from the probe 30, and the detection unit 374 is adjacent The point where the polarity changes from positive to negative is the maximum point, the point where the polarity changes from negative to positive is the minimum point, and the threshold value is obtained by calculating the absolute value of the difference between the adjacent maximum point and minimum point And an identification signal is output. In this way, the contour detection unit 37 detects a region where the absolute value of the difference between the potentials of the local maximum point and the local minimum point adjacent to each other is large as a contour appearing on the tomographic image. The detection unit 374 includes a first signal portion in which the difference between the signal level at the local minimum point and the signal level at the next local maximum point is greater than a threshold value among the low frequency components of the received signal, the value of the local maximum point, The second signal portion whose difference from the value of the minimum point is smaller than the threshold value is distinguished and detected. The contour detection unit 37 outputs the detection result of the first signal portion and the detection result of the second signal portion as an identification signal.

  In the present embodiment, as the low-pass filter, a cutoff frequency can be arbitrarily set and an FIR filter having a linear phase characteristic is used. However, the present invention is not limited to this.

  FIG. 6 is a block diagram showing the configuration of the rising edge enhancement processing unit and the falling edge enhancement processing unit shown in FIG.

  The rising edge enhancement processing unit 361 shown in FIG. 6 includes multiplication circuits 361a and 361b, a delay circuit 361c, and an adder circuit 361d, and a signal obtained by performing a process of multiplying the received signal by a delay and a negative coefficient. A process of adding a signal obtained by multiplying the signal level of the received signal by a positive coefficient is performed.

  More specifically, one of the signals F (x) input to the rising edge enhancement processing unit 361 is multiplied by one or more coefficients (1 + α) by a multiplication circuit 361a to become a signal (1 + α) F (x). The other is a signal (−α) F (x + τ) that is delayed by the time τ by the delay circuit 361c and multiplied by a negative coefficient (−α) by the multiplication circuit 361b. These two signals are further added by the adder circuit 361d, and the rising portion and falling portion of the signal F (x) are emphasized to increase the amplitude of the signal (1 + α) F (x) + (− α ) F (x + τ) and output.

  In this manner, the rising edge emphasis processing unit 361 generates a rising edge emphasis signal in which the rising edge is emphasized by amplifying the signal portion immediately after the rising edge. Note that the rising edge emphasis processing unit 361 further reduces the signal level of the portion having a relatively low signal level immediately after the falling edge, but does not contribute to the clearness of the display in the portion having the low signal level.

  Similar to the rising edge enhancement processing unit 361, the falling edge enhancement processing unit 362 shown in FIG. 6 includes multiplication circuits 362a and 362b, a delay circuit 362c, and an addition circuit 362d, but these combinations are different. . The falling edge emphasis processing unit 362 adds a signal obtained by performing processing for multiplying the received signal by a delay and a positive coefficient and a signal obtained by performing processing for multiplying the signal level of the received signal by a negative coefficient.

  One of the signals F (x) input to the falling edge enhancement processing unit 362 is delayed by the time τ by the delay circuit 362c and multiplied by a coefficient (1 + α) of 1 or more by the multiplication circuit 362a (1 + α) F ( x + τ). The other is a multiplication circuit 362b multiplied by a negative coefficient (−α) to become a signal (−α) F (x), and these two signals are further added by an addition circuit 362d to obtain a signal F (x). The rising and falling portions of the signal are emphasized, and a signal (1 + α) F (x + τ) + (− α) F (x) having an increased amplitude is output.

  In this manner, the falling edge enhancement processing unit 362 generates a falling edge enhancement signal by amplifying the signal portion immediately before the falling edge.

  As illustrated in FIG. 6, the rising edge enhancement processing unit 361 includes a signal obtained by performing processing for multiplying the received signal by a delay and a negative coefficient, and a signal obtained by performing processing for multiplying the signal level of the received signal by a positive coefficient. The falling edge emphasis processing unit 362 adds a signal obtained by multiplying the received signal by a delay and a positive coefficient and a signal obtained by multiplying the signal level of the received signal by a negative coefficient. It is a configuration. By such rising edge emphasis processing unit 361 and falling edge emphasis processing unit 362, emphasis processing symmetrical with respect to the time axis direction is performed.

  The enhancement processing by the falling edge enhancement processing unit 362 further reduces the signal level of the portion with a relatively low signal level immediately before the rising edge, but does not contribute to the clearness of the display for the portion with the low signal level.

  FIG. 7 is a diagram illustrating an input waveform and an output waveform of the rising edge enhancement processing unit and the falling edge enhancement processing unit.

  FIG. 7 shows a rising edge enhancement signal OutputA output from the rising edge enhancement processing unit 361 when a single rectangular wave Input is input to the rising edge enhancement processing unit 361 and the falling edge enhancement processing unit 362. A falling edge enhancement signal OutputB output from the falling edge enhancement processing unit 362 is shown.

  In the rising edge emphasis signal OutputA, the signal level immediately after the rising edge is further increased. The portion immediately after the rising edge corresponds to the portion of the tissue that is brightly displayed on the image, and when the signal level of this portion increases, the end portion of the tissue that is brightly displayed is displayed brighter. In the rising edge emphasis signal OutputA, edge enhancement is performed by lowering the signal level immediately after the falling edge, but the portion immediately after the falling edge is a portion other than the tissue that is displayed brightly on the image, that is, a dark display. The emphasis of the darkly displayed part hardly contributes to the clearness of the display.

  In the falling edge enhancement signal OutputB, the signal level immediately before the falling edge is further increased, contrary to the rising edge enhancement signal OutputA. The portion immediately before the falling edge corresponds to the portion of the tissue that is brightly displayed on the image, and when the signal level of this portion increases, the end portion of the tissue that is brightly displayed is displayed brighter. In the falling edge emphasis signal OutputB, edge enhancement is performed by lowering the signal level immediately before the rising edge, but the portion immediately before the rising edge corresponds to the darkly displayed portion, and the display is clear. Hardly contributes.

  The edge enhancement signal switching unit 38a of the signal generation unit 38 shown in FIG. The edge emphasis signal is generated by switching.

  The edge enhancement signal switching unit 38a is a first signal detected by the contour detection unit 37 when the difference between the signal level at the minimum point and the signal level at the next maximum point is greater than the threshold among the low frequency components. For the portion, the rising edge enhancement signal of the rising edge enhancement processing unit 361 is adopted, and the second signal portion detected when the difference between the maximum point value and the next minimum point value is smaller than the threshold value. The falling edge enhancement signal of the falling edge enhancement processing unit 362 is employed.

  In the signal generation unit 38, an edge detection unit 37 for each of the edge enhancement signal generated by the switching of the edge enhancement signal switching unit 38a and the signal supplied from the amplifier 35 without passing through the edge enhancement processing unit 36. The weighted coefficients are added based on the identification signal from and the added signal is output. The LUT 38e of the signal generation unit 38 outputs coefficients (k1, k2) based on the identification signal output from the contour detection unit 37, and outputs a signal for switching the edge enhancement signal switching unit 38a. The determined coefficients are the edge emphasis signal generated by switching of the edge emphasis signal switching unit 38a by the multiplying circuits 38b and 38c, and the signal supplied from the amplifier 35 without passing through the edge emphasis processing unit 36, respectively. Multiplied by. The two multiplied signals are added by the adder circuit 38d.

  The coefficients k1 and k2 set in the LUT 38e are coefficients for weighting and adding the reception signal input from the edge enhancement processing unit 36 and the reception signal input from the amplifier 34 in the addition circuit 38d. A plurality of coefficients whose weights are changed are prepared so as to be 1 when k1 and k2 are added. The operator can adjust the contrast by selecting one of a plurality of coefficients set in the LUT, for example, based on the contrast of the displayed diagnostic image.

  When the first signal portion is detected by the contour detection unit 37, the LUT 38e switches the edge enhancement signal switching unit 38a so as to adopt the rising edge enhancement signal of the rising edge enhancement processing unit 361, and the contour detection unit When the second signal portion is detected by 37, the edge enhancement signal switching unit 38a is switched so as to adopt the falling edge enhancement signal of the falling edge enhancement processing unit 362. The LUT 38e, when the first signal portion and the second signal portion are detected, is a coefficient (K2) that performs relatively large weighting on the edge enhancement signal generated by the switching of the edge enhancement signal switching unit 38a. > K1), and when the third signal portion excluding the first signal portion and the second signal portion is detected, it is relative to the signal supplied without passing through the edge enhancement processing unit 36. A coefficient (K2 <K1) for performing a large weighting is output.

  FIG. 8 is a diagram for explaining signal generation by the signal generation unit shown in FIG. 3.

  The signal generator 38 does not go through the rising edge enhancement signal (A) from the rising edge enhancement processor 361, the falling edge enhancement signal (B) from the falling edge enhancement processor 362, and the edge enhancement processor 36. The supplied signal is supplied. For the first signal portion (1), the signal generator 38 selects the rising edge enhancement signal (A) from the rising edge enhancement signal (A) and the falling edge enhancement signal (B), and the second signal portion (1) For the signal portion (2), the falling edge enhancement signal (B) is selected. The selected edge emphasis signal and the signal supplied without passing through the edge emphasis processing unit 36 are multiplied by a weighting coefficient and added to each other, but the first signal portion (1) and the second signal portion are added. For the signal part (2), the selected edge enhancement signal is heavily weighted, and for the third signal part (3) that is neither the first signal part (1) nor the second signal part (2) The signal that has been supplied without going through the edge enhancement processing unit 36 is heavily weighted. The received signal output from the signal generation unit 38 is input to the display unit 39, and the display unit 39 has clear edges corresponding to both the rising edge and the falling edge among the outline of the tissue that is brightly shown in the image. The displayed high-contrast tomographic image is displayed in luminance. In addition, for the portion corresponding to the third signal portion (3) that is not the outline of the tissue, an image with weak edge enhancement, that is, with low contrast is displayed.

  FIG. 9 is a diagram illustrating a waveform of a reception signal in the ultrasonic diagnostic apparatus shown in FIG.

  In FIG. 9, (A) in the first stage shows the waveform of the received signal output from the amplifier 35 before being subjected to enhancement processing by the rising edge enhancement processing unit 361 and the falling edge enhancement processing unit 362. In the second stage (B), the maximum point and the minimum point of the low-frequency component obtained by the contour detection unit 37 are indicated by black circles, and in the third stage (C), the reception enhanced by the rising edge enhancement processing unit 361 is shown. The waveform of the signal is shown, the fourth stage (D) shows the waveform of the received signal emphasized by the falling edge emphasis processing unit 362, and the fifth stage (E) is outputted from the signal generation unit 38. The waveform of the received signal that is subjected to enhancement processing on the contour portions (first signal portion and second signal portion) detected by the contour detection unit, and the other third signal portions are not subjected to enhancement processing. (F) in the sixth row shows that the emphasis processing is applied to the signal of (E). And shows the the extracted signal waveform (reference) region. In each stage, the vertical axis indicates the signal level, and the horizontal axis indicates the time (depth) from when the ultrasonic beam is transmitted from the probe to when the reflected wave is received.

  In the second stage (B), the low-frequency component is extracted by passing the signal of the first stage (A) through a low-pass filter, and the difference between the signal level at the minimum point and the signal level at the next maximum point is calculated. The first signal portion (1) larger than the threshold value and the second signal portion (2) where the difference between the maximum point value and the next minimum point value is smaller than the threshold value are detected as contour portions.

  The waveforms of the third stage (C) and the fourth stage (D) are emphasized as compared with the first stage (A), the change in amplitude becomes larger, and the waveform is sharper. In particular, in the waveform of the third stage (C), the signal level increases at the rising edge, typically at the (L) portion. The waveform of the fourth stage (D) has a particularly increased signal level at the falling edge, typically at the (R) portion.

  The waveform of the fifth stage (E) reflects the waveform of the third stage (C) relatively strongly in the section of the first signal portion (1) in the second stage (B), and the second signal In the section (2), the waveform of the fourth stage (D) is relatively strongly reflected, and in the section of the third signal part excluding the first signal part (1) and the second signal part (2). The waveform of the first stage (A) is reflected relatively strongly.

  FIG. 10 is a diagram showing an image displayed with brightness by highlighting the contour portion in the ultrasonic diagnostic apparatus according to the present embodiment. FIG. 11 is a diagram showing the brightness display of the image shown in FIG. 10 for convenience of illustration. Is shown in black.

  FIG. 12 is an image of a comparative example in which only the signal portion immediately after the rising edge in the edge enhancement processing is amplified and the signal portion immediately before the falling edge is not amplified. FIG. 13 is a diagram for convenience of illustration. 12 shows the luminance-displayed portion of the image shown in FIG.

  10 to 13 are the same images representing blood vessels in the body. In addition, the upper side of the figure is the body surface side, and the example of the waveform shown in FIG. 9 described above corresponds to the signal part representing the broken line part shown in FIG.

  In both the image of the ultrasonic diagnostic apparatus of the present embodiment shown in FIGS. 10 and 11 and the image of the comparative example shown in FIGS. 12 and 13, the inner vascular membrane Q is the signal immediately after the rising edge. Due to the amplification of the part, it is displayed with the same level of clarity. Furthermore, the images of the ultrasonic diagnostic apparatus of the present embodiment shown in FIGS. 10 and 11 are clearer up to the outer vascular membrane P (side closer to the body surface) than the images of the comparative examples shown in FIGS. It is displayed. In this way, the tomographic image is displayed in a state in which the outline portion of the tissue is more easily distinguished.

  Next, a second embodiment of the present invention will be described. In the following description of the second embodiment, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 14 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus according to the second embodiment of the present invention.

  The signal generation unit 38 of the ultrasonic diagnostic apparatus 4 illustrated in FIG. 4 includes an addition circuit 48a instead of the edge enhancement signal switching unit 38a (see FIG. 3). The adder circuit 48 a adds the rising edge enhancement signal output from the rising edge enhancement processing unit 361 and the falling edge enhancement signal output from the falling edge enhancement processing unit 362.

  The ultrasonic diagnostic apparatus 4 according to the second embodiment has a configuration because it is not necessary to switch between the rising edge and the falling edge as compared with the case where the signal is switched by the edge enhancement signal switching unit 38a as in the first embodiment. Be concise. Also, in the detection of the contour detection unit 37, it is possible to distinguish between the local maximum point and the next local minimum value, or the local maximum points adjacent to each other without distinguishing between the local maximum value and the next local minimum value. Since the contour may be detected based on the difference between the values of the local minimum points, the configuration is simplified.

  In the first embodiment described above, the signal generation unit 38 receives the reception signal input from the edge enhancement processing unit 36 and the reception signal input from the amplifier 34 based on the coefficients k1 and k2 set in the LUT 38e. However, for example, the weighting coefficients k1 and k2 may be a combination of “0” and “1”, that is, simple switching.

  Further, in the above-described embodiment, it has been described that the contour detection unit 37 outputs the result of comparing the difference between the maximum value and the minimum value with the threshold value. However, the present invention is not limited to this, for example, the contour The detection unit may output a multilevel signal representing the difference between the maximum value and the minimum value as the identification signal, and the signal generation unit may cause the LUT to output a weighting coefficient corresponding to the multilevel identification signal.

3,4 Ultrasonic diagnostic apparatus 30 Probe 31 Transmission / reception circuit 32 Beam forming circuit 33 Band pass filter 34 Detection circuit 35 Amplifier 36 Edge enhancement processing unit 37 Contour detection unit 38 Signal generation unit 38a Edge enhancement signal switching unit 38b, 38c Multiplication circuit 38d Adder circuit 39 Display unit 361 Rising edge emphasis processing unit 362 Falling edge emphasis processing unit 362a, 362b, 361a, 361b Multiplier circuit 361d, 362d Adder circuit 361c, 362c Delay circuit 48a Adder circuit

Claims (4)

Ultrasound that transmits an ultrasonic beam into a subject and displays a tomographic image of a tissue in an ultrasonic transmission / reception area in the subject based on a reflected ultrasonic wave signal reflected and returned from the subject. In the ultrasonic diagnostic equipment,
Rising edge of the received signal is emphasized by adding the signal and performing the process of multiplying a positive coefficient of the signal level of the delay and the negative signal subjected to processing of multiplying the coefficient and said received signal to said reception signal A rising edge emphasis processing unit for generating a rising edge emphasis signal, a signal obtained by multiplying the received signal by a delay and a positive coefficient, and a signal obtained by multiplying the signal level of the received signal by a negative coefficient DOO ultrasonic diagnostic apparatus characterized by comprising an edge enhancement signal generation unit and a falling edge enhancement processing unit for generating a falling edge enhancement signal falling edge is emphasized in the received signal by adding an. The edge emphasis signal generation unit switches the output of the rising edge emphasis processing unit and the output of the falling edge emphasis processing unit to obtain the local minimum and the minimum point of the low frequency component of the received signal. For the first signal portion in which the difference between the signal level at the point and the signal level at the next maximum point after the minimum point is larger than a predetermined threshold, the rising edge emphasis signal is adopted, and the value of the maximum point and the maximum value are detected. It claims the difference between the value of the next minimum point of points having an edge enhancement signal switching unit for generating an edge enhancement signal the falling edge enhancement signal is employed for the second signal portion larger than a predetermined threshold value claim 1 Symbol placement of the ultrasonic diagnostic apparatus. Before Symbol edge enhancement signal generation unit, by adding the output of the falling edge enhancement processing unit and the output of the rising edge enhancement processing unit to each other, the falling edge enhancement signal and the rising edge enhancement signal is added The ultrasonic diagnostic apparatus according to claim 1, further comprising an edge enhancement signal adding unit that generates an edge enhancement signal. The edge enhancement signal is relatively strongly amplified for the first signal portion and the second signal portion of the received signal, and the first signal portion and the second signal portion of the received signal are amplified. For the third signal portion excluding, a signal generation unit that relatively strongly amplifies the reception signal before being input to the edge enhancement signal generation unit and adds the reception signal and the edge enhancement signal to each other The ultrasonic diagnostic apparatus according to claim 2 or 3 .