JPH0693895B2 - Ultrasonic diagnostic equipment - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a video signal processing circuit of an ultrasonic diagnostic apparatus.

[Technical background of the invention and its problems]

As is well known, an ultrasonic diagnostic apparatus emits an ultrasonic beam toward a living body, receives an ultrasonic echo reflected from an acoustic foreign substance in the living body, and based on the intensity of this echo, for example, CRT or the like. It is an apparatus for obtaining a tomographic image of a living body by subjecting the position of an echo to brightness display by displaying the echo position and repeating such scanning while gradually moving the ultrasonic beam.

In such an ultrasonic diagnostic apparatus, an ultrasonic beam emitted toward the living body as described above is reflected by an acoustic foreign substance in the living body, for example, an organ such as stomach or esophagus (hereinafter referred to as an ultrasonic echo. The strength of the echo is usually caused by the above-mentioned acoustic foreign matter. Conventionally, the strong echo and the weak echo are simultaneously displayed on the image display unit such as a CRT.
In order to display the image on the CRT, a strong echo is suppressed by feeding back to a video signal image width circuit which is a circuit for image width of a video signal for displaying an image on the CRT or the like.
In addition, for the desire to clarify the boundary between the parenchyma and the wall of a thick blood vessel, the wall of the gallbladder, the thin blood vessel, etc. of the above-mentioned organs and to emphasize only the weak echo while keeping the strong echo,
Conventionally, a CR time constant circuit is provided in the feedback system of the AGC circuit to temporally change the gain of the video signal amplification circuit to clarify the boundaries of the thick blood vessels and the like.

FIG. 4 is a circuit diagram of the AGC circuit and RC time constant circuit, and FIG.
FIG. 6 and FIG. 6 are explanatory diagrams showing changes in the waveform of the echo signal in the AGC circuit. 4 to 6,
When the video signal P ₁ shown in FIG. 5 (a) is input to the AGC circuit 40 shown in FIG. 4, this video signal is fed by the CR time constant circuit 41 provided in the field back system as shown in FIG. )
The feedback signal P ₂ shown in FIG. 5 is obtained, inverted by the code converter 42, added to the video signal P ₁ , and output as the output signal P ₃ shown in FIG. 5C. Also, the output signal P ₃ is determined by the amplitude of the video signal P ₁ is inputted, the feedback and the video signal P ₁ illustrated in example FIG. 6 (a) is input to the AGC circuit 40 shown in FIG. 4 The signal P ₂ has the waveform shown in FIG. 6 (b), is inverted by the code converter 42, is added to the video signal P ₁ , and is output as the output signal P ₃ shown in FIG. 6 (c). It

Thus, the amplitude of the first input echo signal affects the next input echo signal, for example, as shown in FIG. 6 (c), the next input echo signal is completely lost. There was a problem that it was not displayed.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and emphasizes only the weak echo signal and further emphasizes the gradation difference between the weak echo signals, and the time change of the gain is the amplitude of the echo signal initially input. It is an object of the present invention to provide an ultrasonic diagnostic apparatus that can enhance the edge portion of the weak echo signal regardless of the above.

[Outline of Invention]

The outline of the present invention for achieving the above object is to transmit and receive ultrasonic waves to and from a living body to obtain an echo signal from a deep probe, and then process the echo signal to display an ultrasonic image of the living body. In the ultrasonic diagnostic apparatus, a logarithmic amplifier for amplifying an echo signal from the deep probe, a detection circuit for detecting an output signal of the logarithmic amplifier, a first amplifier for amplifying an output signal of the detection circuit, A delay circuit that delays the output signal of the detection circuit, a second amplifier that inverts and amplifies the phase of the output signal of the delay circuit, an output signal of the first amplifier, and an output signal of the second amplifier. An adder for adding
And a limiting circuit for truncating unnecessary non-display from the output signal of the adder.

Example of Invention

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

FIG. 1 is an embodiment of a circuit for emphasizing a weak echo signal and emphasizing an end portion of the echo signal according to the present invention. In the figure, a probe 3 that transmits and receives an ultrasonic beam to obtain information on, for example, the inside of a living body, and a pulser circuit 2 that generates a pulse for outputting the ultrasonic beam from the probe 3.
And a rate pulse generation circuit 1 for generating a pulse for triggering the pulser circuit 2, for amplifying a reflected wave of ultrasonic waves received by the probe 3 from, for example, the internal organ of the living body. The logarithmic amplifier 4 and the amplified reflected wave are detected by the detection circuit 5 to obtain a video signal. A delay circuit 6 for delaying the video signal, an inverting amplifier 7 for inverting and amplifying the phase of the delayed video signal,
An amplifier 8 for amplifying the video signal without delay
An adder 9 for adding the delayed video signal and the non-delayed video signal, a limiting circuit 10 for truncating a non-display signal unnecessary for processing the video signal, and this unnecessary signal An A / D converter 11 for converting the truncated video signal into a digital signal, and the video signal converted into the digital signal are stored in a frame memory 12. The D / A converter 13 for converting the digitally converted video signal stored in the frame memory 12 into an analog signal again, and the video signal converted into the analog signal are displayed on the monitor 14 to the operator. A tomographic image can be provided.

According to the circuit having such a configuration, the pulse pulse is generated by the rate pulse generating circuit 1 to trigger the pulsar circuit 2 to generate a pulse to excite the probe 3.
The ultrasonic wave output in this manner is irradiated into the living body, for example, and the ultrasonic wave reflected in the living body is received by the probe 3,
The signal is amplified by the logarithmic amplifier 4 and detected by the detection circuit 5 to obtain a video signal. Waveforms for explaining these actions are shown in FIG. In the figure, when the detection output S ₁ shown in (a) is obtained, the output of the amplifier 8 is the output waveform shown in (b) of the figure.
It becomes S ₂ . Next, this video signal is delayed by the delay circuit 6 and multiplied by (-α) by the inverting amplifier 7. The video signal which does not delay this is (1 + α) in the amplifier 8.
The multiplied signals are added by the adder 9 to emphasize the edges, and then the limiter 10 cuts off the non-display signal, the A / D converter 11 converts the digital signal into a digital signal, and the digital signal is stored in the frame memory 12. Output S ₂ of the amplifier 8 shown in the FIG. 2 (b), the output S ₄ of the output waveform S ₃ by inverting amplifier 7 is delayed FIG (c) next adder 9 shown in (d) of FIG. Thus, the rising and falling edges of the echo are emphasized, and the output S ₅ of the limiter 10 has the output waveform shown in FIG.

This digital signal is D / A converted and displayed on the monitor 14 as a luminance-modulated image, where the probe 3 is scanned by the scanner 15 to obtain a tomographic image. In the output shown in FIG. 2 (e), the time width in which the end of the waveform S ₅ is emphasized depends on only the delay time t, as described above, not on the signal amplitude. Since the amplitude of this emphasized portion is amplified by the amplifier 8, the output of the detector 5
As shown in the waveform S ₆ of FIG. 3 (a), even if the tone difference of each echo signal is as small as ΔX, the output of the limiter 10 with the edge emphasized shows the waveform S _{7 of} FIG. 3 (b). As shown in, the gradation difference becomes as large as ΔX (1 + α), and the gradation difference between echo signals is also emphasized by (1 + α) times. Further, since the signal provided for display has the same time width T as that before the edge emphasis, it is possible to prevent the deterioration of the distance resolution.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified and implemented within the scope of the gist of the present invention. For example, it can be used in an electronic scanning type ultrasonic diagnostic apparatus.

〔The invention's effect〕

As described above in detail, according to the present invention, since the end portion enhancement of the echo signal can be performed without the time change of the gain being influenced by the amplitude inputted immediately before, the substantial wall of the blood vessel, the gallbladder wall, the thin blood vessel, etc. It is possible to obtain a clear image of the boundary between and, and it is also possible to emphasize the tone difference between weak echo signals, and the signal to be displayed has the same time width as that before emphasis. Therefore, it is possible to provide an ultrasonic diagnostic apparatus capable of preventing a decrease in distance resolution.

[Brief description of drawings]

FIG. 1 is a block diagram of a video signal processing circuit of an ultrasonic diagnostic apparatus of the present invention, and FIGS. 2A to 2E are time charts showing waveforms of output signals respectively obtained by the video signal processing circuit of the present invention. 3 (a) and 3 (b) are time charts showing waveforms of output signals respectively obtained by the video signal processing circuit of the present invention, and FIG. 4 shows a conventional AGC circuit and a CR time constant circuit of its feedback system. Block diagrams shown in FIGS. 5A, 5B, and 5C are time charts of waveforms of output signals obtained in the block diagram shown in FIG. 4, and FIG.
(A), (b), (c) are time charts of waveforms of output signals obtained in the block diagram shown in FIG. 4, respectively. 1 ... Rate pulse generation circuit, 2 ... Pulser circuit, 3
... Probe, 4 ... logarithmic amplification circuit, 5 ... detection circuit, 6
... delay circuit, 9 ... adder circuit, 10 ... control circuit.

Claims (1)

[Claims] 1. An ultrasonic diagnostic apparatus for transmitting and receiving ultrasonic waves to and from a living body to obtain an echo signal from a deep probe and then processing the echo signal to display an ultrasonic image of the living body, A logarithmic amplifier that amplifies the echo signal from the tentacle,
A detection circuit for detecting the output signal of the logarithmic amplifier, a first amplifier for amplifying the output signal of the detection circuit, a delay circuit for delaying the output signal of the detection circuit, and a phase of the output signal of the delay circuit A second amplifier that inverts and amplifies, an adder that adds the output signal of the first amplifier and the output signal of the second amplifier, and an unnecessary non-display signal from the output signal of the adder. An ultrasonic diagnostic apparatus having a limiting circuit for cutting off.