JPS61187848A - Scanning display control system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] In an ultrasonic diagnostic device that performs fan-shaped scanning using a plurality of beams with different focal points as a pair, the beams focused at a short distance are thinned out, the energy is reduced, and the sending interval is further shortened. This prevents the center of the displayed fan-shaped area from becoming too bright and shortens the scanning period.

[Industrial application field]

The present invention relates to a scanning and display control system for an electronic sector type ultrasonic diagnostic device with a variable aperture or variable focal length, and is intended to provide a clearer image at a shorter distance than before and to shorten the scanning time. It is something.

[Conventional technology]

In the electronic sector type ultrasonic diagnostic apparatus, the probe includes a plurality of ultrasonic transmitting/receiving elements, and performs fan-shaped scanning by selectively driving the elements. FIG. 4 illustrates the mode of fan-shaped scanning, with Bl, B2, . ...Bn is probe 10
This is an ultrasonic beam transmitted from the m ultrasonic transmitting/receiving elements El, E2. ...When all or part of Em is driven with the required delay given to each element, an ultrasonic beam B+ is generated.

B2. B3. .

When a plurality of adjacent ultrasonic transmitting/receiving elements are simultaneously driven with the required delay, an ultrasonic beam B (Bl, B2, etc.) is generated.
...), but the thickness of this beam B is not uniform; it is thin at the focal point and becomes thicker as it moves away from the focal point. Of course, a clearer (higher resolution) image can be obtained by scanning with a narrow beam, so a method of scanning by changing the focus has been considered. For example, a fan-shaped scanning area is divided into the first half (closer to the probe) and the second half (farther from the probe), and the first type of beam has a focus in the center of the first half, and the second type of beam has a focus in the center of the second half. When you scan with
A clear image (with improved resolution) can be obtained over the entire area.

FIG. 5 is a diagram explaining this, where Ba is the first type of beam,
Bb is the second type of beam, and these are treated as a pair,
Send out Ba followed by Bb in the direction of beam B1 in FIG. 4, and send out Ba followed by Bb in the direction of beam B2,
Do the same below. In other words, Ba and Bb are sent in the same direction, and for the first type beam I3a, the reflected wave from a short distance is adopted, the reflected wave from a long distance is not adopted, and the second type beam Bb Do the opposite.

[Problem that the invention seeks to solve]

However, in this conventional method, since the ultrasonic beam is sent out in the same direction multiple times, it takes time to scan the entire area (it takes several times as long as when it is sent out only once). In addition, in fan-shaped scanning, as shown in Figure 4, the beam is concentrated at the center of the fan shape (on the probe side), and the beam pitch is too small (about 0
．． (about 4wm).

For this reason, if there is an ultrasonic reflector at the center of the sector, the reflected signal from the opposite body will be transmitted over many scanning lines (B1°B2...
...) appears above. For example, if the beam width is 3.5N, a point target at a depth of 20 points will appear in 125, or 14, scanning lines, and the images will be overwritten on the display surface, making it too bright and making it impossible to maintain the overall balance. .

The present invention aims to improve these points, and provides a scanning and display control system that performs electronic sector scanning with variable aperture (focus), requires less time, and reduces uneven brightness of displayed images. This is what I am trying to do.

[Means and Examples for Solving the Problems] The present invention has the following features:
A plurality of ultrasound beams with different focuses are sequentially sent out in the same direction, reflected waves are collected or not collected depending on the focus, and the sending directions of the beam pairs are successively different by a fixed angle to perform fan-shaped scanning. In the scanning display control method of electronic sector type ultrasound diagnostic equipment, the ultrasound beam focused at a short distance is
This is characterized in that beam pairs are not thinned out and sent out every predetermined number of beam pairs.

As shown in FIGS. 1 and 2, the present invention also uses a first type of ultrasonic beam Ba having a focus at a short distance and a second type of ultrasonic beam Bb having a focus at a long distance, and these beams are directed in the same direction. The first type of ultrasonic beam and the second type of ultrasonic beam are sent out, but not in all directions, but in one direction as shown in the figure.
Make it second.

That is, beams B1, B3.・・・・・・Ba and B in the direction
b, but beam B2. Only Bb is sent in the Ba, . . . direction. In this way, the ultrasonic beams are thinned out near the probe as shown in the figure, and the fan-shaped center does not shine particularly brightly on the display screen.Also, every other beam Ba is Therefore, the time required for scanning is 3/4 compared to the conventional method that sends out everything.
decreases to

Of course, it is not necessary to thin out every other tree, but to thin out two trees in a row.
+=Ba+Bb, B2=B3=Bb, B4=13a+B
b, etc. may be used. Furthermore, the types of focal points may not be limited to two types, long distance and short distance, but may be three types, such as long distance, intermediate distance, and short distance. The reflected waves of the ultrasonic beam focused at a short distance are those from a short distance, and those from a long distance are rejected, and this is done using a time gate.

The reflected wave of the first type ultrasonic beam Ba focused at a short distance closes the gate in the rejected part, so at the beginning of this rejected period, the first type ultrasonic beam Ba focused at a long distance closes the gate.
It is also conceivable to send . Of course, 73>72 is set so that the reflected wave of the reflected wave non-application period T2 of the beam Ba does not enter into the period T4 of the reflected wave of the beam Bb. Here, the rejection period T2 is the next ultrasound Bb from the end of the recruitment period T1.
The non-adoption period T3 is from the sending point to the start of the recruitment period T4, but there is a reflected wave of Ba even in period T2 (it is just not adopted), and this should not appear in the recruitment period T4. . Considering the existence of this rejected reflected wave, it is best to set the end point of period T2 at the point when the multiple reflected waves have sufficiently attenuated and become negligible. Sending out Bb (
The triangular envelope line indicates the attenuation situation). However, if this is done, the ultrasonic transmission period T='r'++72 etc. will become large.

In order to reduce the period T, it is preferable to accelerate the attenuation of reflected waves, especially multiple reflections. By the way, since the reflected wave of the beam 'Ba scanning a short distance has a small attenuation, a small energy should be sufficient, and if the energy is small, the attenuation will be faster. Also, the problem of excessive brightness in the center of the sector is eliminated. Another embodiment of the present invention from this point of view is shown in FIG. A beam focused at a short distance has low energy as shown by An and An+2, and its reflected wave quickly attenuates to a negligible level. Then, the next beam 3b (Bn, E3n+2'
.

Also in FIG. 3, every other first type beam Ba having a focus at a short distance is omitted, which is the same as in FIG. 2. However, since the beam Ba has a low energy and the sending interval of the next beam Bb is shortened, the time required for scanning the entire area is (3T + + 2 T 2 ) compared to the conventional method shown in Figs. 4 and 5.
/ 4 (T + + 72). However, T
+=Tt,..., T2=T4.・・・
...and so on. This means that if T + = T 2 then 5/
It is 8.

〔Effect of the invention〕

As explained above, according to the present invention, a plurality of ultrasonic beams with different focuses are sequentially sent out in the same direction, reflected waves are collected or not collected depending on the focus, and the sending direction of the beam pair is changed. In an electronic sector type ultrasonic diagnostic device that performs high-resolution diagnosis over the entire area by performing fan-shaped scanning at different angles, it is possible to reduce the brightness of the image in the center of the fan-shaped area, and to reduce the scanning time. can be shortened and is extremely effective.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the scanning display method of the present invention, FIGS. 2 and 3 are diagrams explaining the two sides of the method using waveforms, FIG. 4 is an explanatory diagram of the conventional scanning display method, and FIG. 5 4 is a diagram illustrating the method of FIG. 4 using waveforms. In the drawing, Ba is an ultrasonic beam focused at a short distance, Bb is an ultrasonic beam focused at a long distance, and B+. B2. . . . indicates a beam pair or a beam sending direction.

Claims (3)

[Claims] (1) Sequentially sending out multiple ultrasound beams with different focuses in the same direction, collecting or not collecting reflected waves depending on the focus, and sequentially changing the sending direction of such beam pairs by a fixed angle. A scanning display control method for an electronic sector type ultrasonic diagnostic apparatus that performs fan-shaped scanning, characterized in that ultrasonic beams focused at a short distance are thinned out every predetermined number of beam pairs and are not sent out. (2) The scanning display control system according to claim 1, wherein the transmitted ultrasonic beam focused at a short distance is made weaker than the ultrasonic beam focused at a long distance. (3) The time interval between the ultrasonic beam focused at a short distance and the next ultrasonic beam focused at a far distance is:
3. The scanning display control method according to claim 2, wherein the time interval is further made shorter than the time interval between the ultrasonic beam and the ultrasonic beam focused at a long distance that is transmitted next.