JP2534488B2 - Ultrasonic tomography - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultrasonic tomographic apparatus that obtains a tomographic image of a diagnostic region of a subject by using ultrasonic waves, and particularly to an image of a gain set in a gain control circuit. The present invention relates to an ultrasonic tomographic apparatus that can be automatically controlled according to the intensity distribution of a signal and can increase the control processing speed.

[Prior Art] As shown in FIG. 6, a conventional ultrasonic tomography apparatus includes an ultrasonic wave transmitting / receiving unit 1 which emits an ultrasonic beam to a diagnostic region of a subject and receives a reflected wave thereof, and the ultrasonic wave transmitting / receiving unit 1. A gain control circuit 2 for controlling the gain for receiving and amplifying the echo signal obtained in the section 1, an A / D converter 3 for converting the output signal from the gain control circuit 2 into a digital signal, and this A / D conversion The image memory 4 for storing the digital image signal from the device 3, the D / A converter 5 for converting the image signal read from the image memory 4 into an analog signal, and the D / A converter 5 And a display 6 for displaying analog signals. Then, in order to change the gain of the gain control circuit 2, the operator controls the gain control provided on the operation panel connected to the gain control circuit 2 while observing the tomographic image displayed on the screen of the display 6. The desired gain was controlled by manually operating the variable resistor 7 of.

[Problems to be solved by the invention]

However, in such a conventional ultrasonic tomography apparatus, the gain of the gain control circuit 2 is set by the operator manually operating the variable resistor 7, and the gain control cannot be performed automatically. There wasn't. In this case, the intensity of the image signal stored in the image memory 4 varies depending on the individual subject, and even within the same subject, it varies depending on the organ of the diagnostic region. Therefore, measurement is performed on the diagnostic region of each subject. I had to manually adjust the gain each time. Therefore, the gain control operation is complicated, and it takes time to obtain an image with a desired density. As a result, the efficiency of diagnosis may decrease. Further, since the operator manually sets the gain of the gain control circuit 2, the gain of the gain control circuit 2 may be different depending on the skill and preference of the operator, and the image quality of the tomographic image obtained may be different. In some cases, the images became uniform, and diagnosis could not be performed with images of equivalent density.

Therefore, the present invention can deal with such a problem and automatically control the gain set in the gain control circuit according to the intensity distribution of the image signal, and increase the control processing speed. It is an object of the present invention to provide an ultrasonic tomography device that can be used.

[Means for solving problems]

Means of the present invention for solving the above-mentioned problems include an ultrasonic wave transmitting / receiving unit that outputs an ultrasonic beam and a reflected wave thereof to a diagnostic region of a subject and receives an echo signal obtained by the ultrasonic transmitting / receiving unit. A gain control circuit that controls the gain to be amplified, an A / D converter that converts the output signal from this gain control circuit into a digital signal, and an image memory that stores the digital image signal from this A / D converter , Converts the image signal read from this image memory into an analog signal
In an ultrasonic tomography apparatus having a D / A converter and a display that displays an analog signal from this D / A converter,
On the output side of the A / D converter, a gain control memory for storing a digital image signal in parallel with the image memory is provided,
The gain control memory compares the intensity distribution value of the image signal obtained by integrating the signal intensity of each pixel of the image signal stored in the gain control memory with a predetermined value, and the image signal Is connected to an intensity distribution processing circuit for controlling the intensity distribution to fall within a predetermined range, a predetermined value control circuit for setting the predetermined value is connected to the intensity distribution processing circuit, and the intensity distribution is This is performed by an ultrasonic tomography apparatus which inputs a control signal from the processing circuit to the gain control circuit and automatically controls the gain of the gain control circuit.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of an ultrasonic tomography apparatus according to the present invention. This ultrasonic tomography device obtains a tomographic image of a diagnostic region of a subject using ultrasonic waves,
Ultrasonic wave transmitter / receiver 1, gain control circuit 2, and A / D converter 3
, Image memory 4, D / A converter 5, and display 6
And have.

The ultrasonic transmission / reception unit 1 emits an ultrasonic beam toward a diagnostic region of a subject by a probe (not shown) and receives a reflected wave from the diagnostic region to obtain an echo signal. However, it has a control circuit, a pulse generator, a reception amplifier, etc. inside. The gain control circuit 2 controls the gain for receiving and amplifying the echo signal obtained by the ultrasonic wave transmitting / receiving section 1. The A / D converter 3 converts the signal output from the gain control circuit 2 from an analog amount to a digital amount. The image memory 4 stores the digital image signal output from the A / D converter 3. The D / A converter 5 converts the image signal read from the image memory 4 into an analog signal. The display 6 displays the analog signal output from the D / A converter 5 as a tomographic image, and is composed of, for example, a CRT.

Here, in the present invention, the gain control memory 13 is provided in parallel with the image memory 4 on the output side of the A / D converter 3, and the intensity distribution processing circuit 8 is provided in the gain control memory 13. And a predetermined value control circuit 9 is connected to the intensity distribution processing circuit 8, and the control signal S ₁ output from the intensity distribution processing circuit 8 is input to the gain control circuit 2. There is. Memory for gain control
Reference numeral 13 stores a digital image signal for controlling the gain of the gain control circuit 2. The intensity distribution processing circuit 8 compares the value obtained by integrating the signal intensity of each pixel of the image signal stored in the gain control memory 13, that is, the intensity distribution of the image signal with a preset predetermined value, The intensity distribution of the image signal is controlled so that the intensity distribution falls within a predetermined range. For example, the intensity distribution of the image signal stored in the gain control memory 13 has a RAM (read-write memory at any time). Is greater than a preset value, the control signal S ₁ for reducing the gain of the gain control circuit 2 is output, and when it is smaller than another preset value, the gain of the gain control circuit 2 is reduced. A control signal S ₁ for increasing is output. Predetermined value control circuit 9
Is for setting a predetermined value from a certain value to another value for the intensity distribution processing circuit 8 or changing it as necessary. For example, as the first level, the values ab and the second level are set. The values c to d, and the third level values e to f, ... Can be stored in a stepwise manner. An input device 10 such as a keyboard for setting the predetermined value is connected to the predetermined value control circuit. The control signal S ₁ output from the intensity distribution processing circuit 8 is in the form of an analog voltage signal and is input to the gain control circuit 2 via the analog switch 11. This analog switching device 11 includes an analog voltage signal S ₂ from the variable resistor 7 for gain control by the conventional manual operation shown in FIG. 6 and a control signal S ₁ of the analog voltage signal from the intensity distribution processing circuit 8. Are input to the gain control circuit 2 by switching on and off, and the signals S ₁ and S ₂ are switched by turning on and off the changeover switch 12 provided in the analog switcher 11. For example, when the changeover switch 12 is turned on, the contact in the analog changeover device 11 is switched to the variable resistor 7 side to be in the state of gain control by manual operation, and when it is turned off, the analog changeover device 11 is turned on. The contact inside is switched to the intensity distribution processing circuit 8 side, and the automatic gain control is performed.

Next, the operation of the ultrasonic tomography apparatus of the present invention thus configured will be described. First, under the control of the ultrasonic transmission / reception unit 1, an ultrasonic beam is emitted to a diagnostic site of a subject by a probe and the reflected wave is received. Next, the echo signal obtained by the ultrasonic transmission / reception unit 1 is input to the gain control circuit 2 and is received and amplified with a gain set appropriately.
Next, the echo signal received and amplified by the gain control circuit 2 is input to the A / D converter 3 and converted into a digital signal. Then, the digital image signal from the A / D converter 3 is input to and stored in the image memory 4. At this time, the digital image signal is also input to and stored in the gain control memory 13 provided in parallel with the image memory 4. Next, the image signal read from the image memory 4 is input to the D / A converter 5 and converted into an analog signal. Then, the analog signal from the D / A converter 5 is input to the display 6, and a tomographic image of the diagnostic region of the subject is displayed on the screen.

In such a state, in order to control the gain of the gain control circuit 2 by manual operation, first, the changeover switch 12 is turned on. Then, the contacts in the analog switch 11 are switched to the variable resistor 7 side, and the analog voltage signal S ₂ from the variable resistor 7 is input to the gain control circuit 2. As a result, the operator can manually control the gain by operating the variable resistor 7 while observing the tomographic image displayed on the screen of the display 6 as in the conventional case. At this time, the image memory 4 stores the image signal having the gain set by the variable resistor 7. If the gain set by the variable resistor 7 is large, the image signal having a strong intensity distribution is stored in the image memory 4, and if the gain set is small, the image signal having a weak intensity distribution is stored in the image memory 4. It Therefore, the density of the image displayed on the display 6 changes.

Next, in order to automatically control the gain of the gain control circuit 2, the changeover switch 12 is turned off. Then, the contacts in the analog switch 11 are switched to the intensity distribution processing circuit 8 side, and the control signal S ₁ from the intensity distribution processing circuit 8 is input to the gain control circuit 2. At this time, the intensity distribution processing circuit 8
Operates in the procedure of the flowchart shown in FIG. Here, a certain value Kl and another value Ks (Kl> Ks) are input to the intensity distribution processing circuit 8 in advance by using the input device 10 shown in FIG. A predetermined value having a range of Ks to Kl is set. First, the signal strength of each pixel is integrated with respect to the image signal stored in the gain control memory 13. That is, the value of the intensity distribution of the image signal stored in the gain control memory 13 is obtained. Then, the value is ΣD
(Step A). Next, it is judged whether or not the value ΣD of the intensity distribution of the image signal obtained as described above is larger than the predetermined value Kl set in the intensity distribution processing circuit 8 (step B). Now, if ΣD> Kl, step B proceeds to the “YES” side, and the intensity distribution processing circuit 8 lowers the gain by the control signal S ₁
Is output (step C). Then, this control signal S
₁ is input to the gain control circuit 2 via the analog switch 11 shown in FIG. ₁ , and the gain of the gain control circuit 2 is lowered according to the control signal S ₁ . As a result, a new image signal whose intensity distribution is weakened is stored in the image memory 4 and the gain control memory 13. In this state, the procedure returns to the step A shown in FIG. Then, steps A → B → C are repeated, and when ΣD ≦ Kl, step B is “N
Exit to the "O" side.

Next, it is judged whether the new intensity distribution value ΣD of the image signal whose intensity distribution is weakened as described above is smaller than another predetermined value Ks set in the intensity distribution processing circuit 8 (step D). If ΣD <Ks, step D is “YES”.
Control signal for increasing the gain.
Output S ₁ (step E). Then, this control signal S ₁
Is input to the gain control circuit 2 through the analog switch 11 shown in FIG. 1, and the gain of the gain control circuit 2 is increased according to the control signal S ₁ . As a result, a new image signal whose intensity distribution has been strengthened is added to the image memory 4 and the gain control memory.
It will be stored in 13. In this state, the procedure returns to the step A shown in FIG. And steps A → B → D → E
The above steps are repeated, and when ΣD ≧ Ks, step D exits to the “NO” side.

As a result, the intensity distribution is controlled to be weakened by repeating steps A → B → C, and
A new image signal controlled so that the intensity distribution is strengthened by repeating B->D-> E is stored in the image memory 4 and the gain control memory 13. In this state, the procedure returns to the step A shown in FIG. And steps A → B →
By repeating D, the state is automatically controlled to Ks ≦ ΣD ≦ Kl. Therefore, the gain of the gain control circuit 2 is automatically controlled by a predetermined value having a range of Ks to Kl preset in the intensity distribution processing circuit 8, and the intensity distribution of the image signal stored in the image memory 4 is preset. It falls within the specified range. As a result, the display 6 displays a tomographic image with a preset desired density. The gain of the gain control circuit 2 can be arbitrarily changed by changing the predetermined values Kl and Ks set in the intensity distribution processing circuit 8.

In the above, since the gain control memory 13 for gain control is provided separately from the image memory 4 for displaying the tomographic image, the processing speed for automatically controlling the gain of the gain control circuit 2 is increased. You can

3A to 3C are flowcharts showing another embodiment of the operation of the intensity distribution processing circuit 8. In this embodiment, the operation of the flow chart shown in FIG. 2 is performed separately depending on the depth division from the surface of the diagnostic region. As shown in FIG. Depending on the depth, the neighborhood part 4n (0-1 / 3) and the middle part 4m (1
/ 3 ~ 2/3) and deep 4f (2/3 ~ 3/3)
The signal strength of each area is integrated. In this case, the intensity distribution processing circuit 8 is previously provided with the input device 10 shown in FIG.
~ Kln (Kln> Ksn) in the range of 4m
Is set to a predetermined value having a range of Ksm to Klm (Klm> Ksm), and a predetermined value having a range of Ksf to Klf (Klf> Ksf) is set for the deep portion 4f. Then, as for the neighboring portion 4n, as shown in FIG. 3 (a), the signal strength of each pixel of the image signal stored in the gain control memory 13 in step A is integrated in the area from the beginning to 1/3. Then, in step B, the value is set to ΣDn and the predetermined value Kl.
While comparing with n, in step D, ΣDn and a predetermined value Ksn
Compare with As for the intermediate portion 4m, as shown in FIG. 3 (b), in step F, the gain control memory 13
The signal intensity for each pixel of the image signal stored in
From 2 to 3/3, and add the value as ΣDm,
In step G, ΣDm is compared with the predetermined value Klm, and in step I, ΣDm is compared with the predetermined value Ksm.
Further, for the deep portion 4f, as shown in FIG. 3 (c), the signal intensity of each pixel of the image signal stored in the gain control memory 13 in step K is integrated in the area from 2/3 to the end. , That value is set as ΣDf, and in step L, the above ΣDf is compared with a predetermined value Klf, and at the same time, step N
Then, ΣDf is compared with a predetermined value Ksf. Then, the flowcharts shown in FIGS.
, Forms a loop as a series of operations, and outputs a control signal S ₁ n for controlling the neighboring portion 4n in the middle thereof (steps C and E in FIG. 3 (a)), and for controlling the intermediate portion 4m. The control signal S ₁ m is output (step H in FIG. 3 (b),
J), outputting the control signal S ₁ f for controlling the deep portion 4f (steps M and O in FIG. 3 (c)) and sending it to the gain control circuit 2 via the analog switch 11 shown in FIG. To do. Therefore, in this embodiment, the gain of the gain control circuit 2 can be automatically controlled according to the depth division from the surface of the diagnostic region. In this case, the number of signal lines connected from the intensity distribution processing circuit 8 to the analog switch 11 in FIG. 1 is three. In addition, in FIGS. 3A to 3C and FIG. 4, the area of the gain control memory 13 is described as being divided into three areas according to the depth from the surface of the diagnostic region. The invention is not limited to this, and may be divided into two or four or more sections.

FIG. 5 is an explanatory diagram of the gain control memory 13 for explaining still another embodiment of the operation of the intensity distribution processing circuit 8.
In FIG. 5, for example, the shaded area P of the gain control memory 13
When the signal intensity of the image signal stored in the area is “1” or more and the signal intensity of the image signal stored in the other area Q is “0” level, all the image signals stored in the areas P and Q are stored. When the signal intensity of each pixel of the image signal is integrated, the automatically controlled gain at this time cannot be said to be sufficiently adapted to the displayed tomographic image. Therefore, in step A of the flowchart shown in FIG. 2, when the signal intensity of each pixel of the image signal stored in the gain control memory 13 is integrated, a threshold value of the signal intensity (for example, “1”) is set in advance. After setting, only the image signals having a signal intensity larger than this threshold value are integrated to obtain the value as ΣDi, and the number N of the integrated pixels is counted, and the above ΣDi is divided by N to obtain the average value ΣDh Ask for. Then, ΣDh is set as the value of the intensity distribution of the image signal stored in the gain control memory 13. The operation after step B is exactly the same as the procedure of the flowchart shown in FIG. In the case of this embodiment, a gain control signal is actually generated from an image signal of only a portion having a brightness of a certain level or more as an image, as indicated by a hatched portion P shown in FIG. The gain that is well adapted to can be automatically controlled.

〔The invention's effect〕

Since the present invention is configured as described above, the A / D converter 3
An image obtained by integrating the signal intensity of each pixel of the image signal stored in the gain control memory 13 by the intensity distribution processing circuit 8 connected to the gain control memory 13 provided in parallel on the output side of the image memory 4. The value of the signal intensity distribution is compared with a preset predetermined value, and a control signal S ₁ for controlling the intensity distribution of the image signal so as to be within a predetermined range is sent to the gain control circuit 2, The gain set in the gain control circuit 2 can be automatically controlled according to the intensity distribution of the image signal sent to the image memory 4. Therefore, the gain control operation is simple, and an image having a desired density can be obtained in a short time. Particularly, since the gain control memory 13 for gain control is provided separately from the image memory 4 for displaying the tomographic image, the processing speed for automatically controlling the gain of the gain control circuit 2 can be increased. it can. Therefore, the efficiency of diagnosis can be improved. Further, the image quality of the obtained tomographic image can be made uniform without being affected by the difference in the subject or the diagnosis site or the skill or preference of the operator. Therefore, uniform diagnosis can be performed by using images having the same image quality and density.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an ultrasonic tomography apparatus according to the present invention, FIG. 2 is a flow chart showing the operation of an intensity distribution processing circuit, and FIGS. 3 (a) to 3 (c) are operations of the intensity distribution processing circuit. FIG. 4 is a flow chart showing another embodiment of the present invention, FIG. 4 is an explanatory diagram of a gain control memory for explaining the other embodiment shown in FIGS. 3 (a) to 3 (c), and FIG. 5 is an intensity distribution processing circuit. FIG. 6 is an explanatory view of a gain control memory for explaining still another embodiment of the operation of FIG. 6, and FIG. 6 is a block diagram showing a conventional ultrasonic tomography apparatus. 1 ... Ultrasonic wave transceiver, 2 ... Gain control circuit, 3 ... A /
D converter, 4 ... Image memory, 5 ... D / A converter, 6 ...
Display, 7 ... Variable resistor, 8 ... Intensity distribution processing circuit, 9 ... Predetermined value control circuit, 10 ... Input device, 11 ...
Analog switch, 12 …… Changeover switch, 13 …… Gain control memory, S ₁ …… Control signal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-55-5661 (JP, A) JP-A-61-238236 (JP, A) JP-A-57-209042 (JP, A)

Claims (1)

(57) [Claims] 1. An ultrasonic wave transmitting / receiving unit for emitting an ultrasonic beam to a diagnostic region of a subject and receiving a reflected wave thereof, and a gain control for controlling a gain for receiving and amplifying an echo signal obtained by the ultrasonic wave transmitting / receiving unit. Circuit, the A / D converter that converts the output signal from this gain control circuit into a digital signal, the image memory that stores the digital image signal from this A / D converter, and the image memory that reads the image signal. In an ultrasonic tomography apparatus having a D / A converter that converts an image signal into an analog signal and a display that displays an analog signal from this D / A converter, at the output side of the A / D converter A gain control memory for storing a digital image signal is provided in parallel with the image memory. The gain control memory has an image obtained by integrating the signal intensity of each pixel of the image signal stored in the gain control memory. The intensity distribution processing circuit is connected to the intensity distribution processing circuit for comparing the intensity distribution value of the signal with a preset predetermined value and controlling the intensity distribution of the image signal so that the intensity distribution falls within a predetermined range. Connects a predetermined value control circuit for setting the predetermined value, and inputs a control signal from the intensity distribution processing circuit to the gain control circuit to automatically control the gain of the gain control circuit. An ultrasonic tomography device characterized in that