JPH02136129A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PURPOSE:To obtain an image reduced in noise by enhancing the directional characteristics of the whole of a probe by providing a low-pass filter to reduce a side lobe component. CONSTITUTION:When a signal is sent out from a transmission circuit 1, a scanning driving circuit 2 successively drives the respective elements 50 of a probe 8 on the basis of said signal not only to transmit an ultrasonic wave to an object to be measured but also to send out the receiving signal thereof to a receiving circuit 3. The receiving circuit 3 amplifies the receiving signal to send out the amplified signal to a signal processing circuit 4 which in turn delays the input signal corresponding to the position of each of the respective elements 50 to apply signal processing such as addition processing to said signal to send out the same to a low-pass filter 5. The low-pass filter 5 attenuates a frequency component larger than the center frequency of the probe 8 so as to cut said component. Therefore, a side lobe component is reduced and, as a result, by taking a side lobe level largely, the noise of an image can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultrasonic diagnostic apparatus using a convex scanner, and particularly to side lobes thereof.

[Prior Art] FIG. 5 is an explanatory diagram showing the arrangement of vibrators in a probe of a convex scanner. In the figure, (50)
are each element of the probe, which are arranged in an arc shape.

Since the spacing between the probe elements (50) of the convex scanner is smaller than that of the linear scanner, there is a restriction that the probe element width W (≦pitch P) cannot be made large.

FIG. 6 is a diagram showing the directivity characteristic of one element of the probe, and since the element width W of the probe cannot be made large as described above, the directivity is broad.

Figure 7 is a diagram showing the overall beam directivity of the probe, and since each probe (50) has broad directivity, the side lobe is large, and the side lobe defined here as shown in the figure is The situation was such that the lobe level L could not be increased.

[Problem to be solved by the invention] In the conventional ultrasonic diagnostic equipment as described above, it is not possible to obtain a large sidelobe level, so if there is a signal with a high signal level at a position outside the field of view, it will appear as if it were in the field of view. There is a problem in that the image is displayed on the display device as if it were in the image, and noise is included in the image.

The present invention was made to solve this problem, and an object of the present invention is to obtain an ultrasonic diagnostic apparatus that makes it possible to reduce image noise by increasing the sidelobe level L.

[Means for Solving the Problems] An ultrasonic diagnostic apparatus according to the present invention includes a receiving signal processing system of a convex scanner provided with a low-pass filter that attenuates frequency components higher than the center frequency of a probe of a compe-socks scanner. It is something.

[Function] In this invention, 1
By attenuating the frequency components higher than the center frequency of the probe among the received signals received by the probe, the sidelobe components are reduced, and as a result, the sidelobe level can be increased.

Embodiment FIG. 1 is a block diagram showing the configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. In the figure, (1) is the transmitting device, (2) is the scanning circuit, (3) is the receiving circuit, (4)
is a signal processing circuit, (5) is a low-nos filter, (6
) is an amplification/detection circuit, (7) is a display device, and (8) is a probe.

The ultrasonic diagnostic apparatus configured as described above has a transmitting circuit (
When a transmission signal is sent from 1), the scanning circuit (2) sequentially drives each element (50) of the probe (8) using the signal to transmit ultrasonic waves to the object A#j, and The received signal is sent to the receiving circuit (3). The receiving circuit (3) amplifies the received signal and then sends the signal processing circuit (4) to the signal processing circuit (4).
). The signal processing circuit (4) delays the human input signal according to the position of each element (50), performs signal processing such as addition processing, and sends the signal to the low-pass filter (5).

FIG. 2 is a characteristic diagram of the low-pass filter (5), which attenuates and cuts frequency components higher than the center frequency of the probe (8). Therefore,
In the output signal from the signal processing circuit (4), frequency components higher than the center frequency of the probe (8) are cut off.

Figure 3 is a characteristic diagram showing the overall directivity characteristics of the probe (8).
Since the frequency components larger than the center frequency of , are cut, the sidelobe components are reduced, and the sidelobe level L can be increased. Incidentally, in FIG. 3, the broken line indicates the characteristic when the low and low filter (5) is not provided.

The signal from which frequency components higher than the center frequency of the probe (8) are removed and sorted by the low-pass filter (5) is amplified and detected by the amplification/detection circuit (6), and then the display device I
(7), and the display device (7) displays an image (elephant) corresponding to the object A11l. At that time, the side lobe level L can be set large, so it is possible to display an image with less noise. It becomes.

FIG. 4 is a diagram showing the measured values of the directivity characteristics of the probe according to the present invention and the conventional one. As is clear from this figure, according to the present invention, the side lobe components are smaller. I understand.

[Effects of the Invention] As described above, according to the present invention, a lobe filter is provided to reduce sidelobe components, so that the directivity of the entire probe is improved and an image with less noise is obtained.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the characteristics of the low-pass filter shown in Fig. 1, and Fig. 3 shows the directivity characteristics of the probe. FIG. 4 is a characteristic diagram showing actually measured values of the directional characteristics of the probe. FIG. 5 is an explanatory diagram of the convex scanner, and FIGS. 6 and 7 are its characteristic diagrams. In the figure, (1) is a transmitting circuit, (2) is a scanning circuit, (
3) is a receiving circuit, (4) is a signal processing circuit, (5) is a low-pass filter, (6) is an amplification/detection circuit, (7) is a display device, and (8) is a probe.

Claims (1)

[Claims] An ultrasonic diagnostic apparatus using a convex scanner, characterized in that a received signal processing system of the convex scanner is provided with a low-pass filter that attenuates frequency components higher than the center frequency of a probe of the convex scanner. Ultrasonic diagnostic equipment.