JPH01288244A - Ultrasonic diagnosing device having video editing device - Google Patents

Abstract

PURPOSE:To prevent a white line from going into a final display picture even when a signal route is switched by executing a reading control from a storing means so as to restore a continuity except for the signal of an area to be overlapped among scanning signals. CONSTITUTION:Electronic focusing circuits 6A-6D classify a subject into four zones according to a distance, and receiving signals by wave-sending signals to connect focuses, respectively, are phasing-added. A changeover switch 8 switches scanning line signals F1-F4 different in focusing positions by a timing according to the distances of respective focusing positions, the signals are outputted by being synthesized to a scanning line signal Fs for one line, and a band-pass filter 9 removes unnecessary frequencies of a high band and a low band. A logarithmic amplifier 10 level-compresses the dynamic range to be very wide of the receiving signal so as to make it adaptive to the characteristics of a photosensitive material and a CRT, the output signal is detected by a detector 11, and it is converted to a digital signal by an AD converter 12. A read/write control logic circuit 13 removes a noise part at the time of reading the inputted scanning line signal from a frame memory, and the signal, in which the nose is removed, is displayed on the CRT.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to video editing in which echo signals are edited so as to receive echoes while switching the focus in order to obtain echo images with good resolution over the entire area. The present invention relates to an ultrasonic diagnostic apparatus having a device.

(Prior art) Ultrasonic diagnostic equipment transmits ultrasonic waves into the subject's body, and since the reflected waves vary depending on each tissue or lesion, this is converted into an image and displayed for diagnostic purposes. . In this case, if you transmit and receive waves at a single focal point and display the reflected waves from a reflector at a long distance and the reflected waves from a reflector at a short distance on the same screen, it will not be possible to display the entire image in a good manner. It is difficult to display with resolution. To solve this problem, the receiver dynamic focus method changes the focus position to track the reflection source during reception, or the receiver dynamic focus method scans the same area several times and changes the transmitter/receiver focus for each scan. A multi-stage focusing method is used in which regions where resolution can be obtained are edited individually via an image memory and then connected and displayed on a display device. The reception dynamic focus method is a method suitable for fast-moving organs because it receives waves at different focal points depending on the distance for each transmission, so there is no need to reduce the image completion speed. Since the focus cannot be matched to all the focal points, the resolution is slightly inferior to the multi-step focusing method. However, in order to realize the receiving dynamic focus method using a focus switching method like this, it is necessary to have several types of electronic focus mechanisms redundantly, and to divide each of them into each required focal position in advance. In the course of wave reception, the signal path is switched so that the reflected wave in the corresponding section is connected to the output of the electronic focusing means corresponding to the time period in which the wave is being received.

(Problem to be Solved by the Invention) By the way, in such a switching type reception dynamic focusing method, a portion where the optimum resolution can be obtained is determined from the phased output signals of the reception beamformer having 0 sets of different focuses. In order to connect these signals to obtain a scanning line signal, the signals are switched in the high frequency section, intermediate frequency section, or video signal section to perform the connection. Noise entered the area where the connections were made, appearing as white lines on the screen, and this was especially noticeable in areas where the signal level was low.

There is also the problem that the image quality changes where the signal switches, but the most problematic point is that white lines appear due to switching noise.

In order to avoid this, the downstream stages of the demultiplexer, each consisting of a combination of delay lenses (focus determining means of the receiving beamformer) with different focal lengths, are prepared in parallel for each focal point, and the received signals are detected. There is an idea to combine it at the point where it goes into the frame memory to at least prevent the spike noise mixed in at high frequency from being detected and appearing as a white line, but the circuit scale would be too large and the cost would be high. This is a problem.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to use ultrasonic waves having a video editing device in which a white line does not appear on the final display screen even if the signal path is switched in a switching type receiving dynamic focus method. The objective is to realize a diagnostic device.

(Means for Solving the Problems) The present invention solves the above problems by editing echo signals so as to receive echoes while switching the focus in order to obtain echo images with good resolution over the entire area. In an ultrasound diagnostic apparatus having a video editing device, a plurality of electronic focus control means each perform phasing and summation of scanning line signals of different focuses, and output signals from the electronic focus control means are controlled at different delay times including zero. a switching means for switching the output signals of the delay means and combining them into one scanning line data; a storage means for writing the combined scanning signals as they are; The apparatus is characterized by comprising a read control means for controlling read from the storage means so as to restore continuity except for signals in the area.

(Function) Scanning line signals in areas with different focal points are transmitted and received, and the received signals are phased and summed by electronic focusing means in each area, and then delayed by different delay times.

The switching means sequentially switches and synthesizes the delay-processed signals of each area at time intervals corresponding to the focal position, and after signal processing J3 and storage, images of areas overlapping between signals of adjacent areas with different delay times are synthesized. It is removed together with the joint, read out from the storage means, and displayed on the display device.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

In the figure, 1 is a transmit trigger oscillator that oscillates a trigger signal for generating a transmit pulse.The output trigger signal is input to a transmit beam former 2 to form a sound ray, so for example 64 Separated into line signals.

3 appropriately switches the 64 lines of input signals from the transmit beam former 2 to form sound rays and scan them, and switches the reflected wave reception signal of each sound ray to correspond to the element position within the aperture plane. This is a scanner switch that recombines signals for lines, and is arranged in two stages to save on the number of switches, with a transmitting/receiving circuit 4 provided in the middle of the two stages. The transmitting/receiving circuit 4 includes a transmitting power amplifier.

Transmission/reception switch. Includes receiving amplifier, etc. Reference numeral 5 denotes an ultrasonic probe array composed of a large number of transducer elements that receive a high-frequency signal q for transmission, oscillate an ultrasonic wave, and receive a reflected wave and convert it into a high-frequency signal. 6Δ~
6D is four electronic focus circuits, each of which is a receiving beamformer, which classifies the subject into four zones based on distance, and electronic focus circuits 6A, G, and 6D are the closest to the zone 0°, and electronic focus circuit 6B is the next closest zone. Distance zone 1, N child focus circuit 6C is the next farthest distance zone 2. Electronic focus circuit 6D is the farthest zone 3
The received signals from the transmitted signals focused on each are phased and summed. Each electronic focus circuit 6△~6D of received signal
The distribution is performed by the scanner switch 3.

7B is a delay circuit that delays the signal from the electronic focus circuit 6B by Δτ and outputs the F2 signal. 7C is a delay circuit that delays the signal from the electronic focus circuit 6C by Δτ2 and outputs the F2 signal.
The delay circuit 7D outputs the F3 signal and is a delay circuit that delays the signal from the electronic focus circuit 6D by Δτ3 and outputs the F4 signal. The electronic focus circuit 6Δ outputs an F1 signal that is not subject to delay. The amount of delay has the following relationship.

Δτ3>Δτ2>Δτt>0 8 is one scanning line signal Fs by switching four scanning line signals F1 to F4 signals with different focal positions at a timing according to the distance of each focal position in zones O to zone 3. This is a focal zone switch that synthesizes and outputs the image. 9
is a bandpass filter (
(hereinafter referred to as BPF), 10 is a logarithmic amplifier that performs level compression to adapt the extremely wide dynamic range of the received signal to the characteristics of the photosensitive material or CRT. is converted into a digital signal. Reference numeral 13 denotes a read/write control logic circuit which includes a frame memory, a write address generator, a read control circuit, a synchronization signal generator, etc., and removes noise when reading the input scanning line signal from the frame memory. The noise-removed signal is displayed on a CRT.

FIG. 3 shows an outline of the internal structure of the fortune-telling control logic circuit 13 and one embodiment of the circuits subsequent thereto. In the figure, the first
The same parts as in the figure are given the same reference numerals. In the figure, 21
23 is a frame memory in which data for one frame is input by changing the focal zone with the switch 8 and is written in accordance with the fortune-telling address from the address generation circuit 22; 23 is data written in the frame memory 21; ID from the synchronization signal generator 24
, VD signals IIJ and III. There are three types of data read into the frame memory 21 by the reading address of the reading address generation circuit 22:

(a) Linear scan for horizontal reading (0) Vertical old linear scan for vertical reading (c) Hikta scan for vertical writing curve reading The readout control circuit 23 writes as described above based on the HD double signal and the VD double signal. Read the stored data.

25 is an AD converter that converts the read data from the frame memory 21 into an analog signal, and 26 is an amplifier that amplifies the analog signal and supplies it to the CRT 27.

Next, the operation of the embodiment configured as described above will be explained.

The trigger signal outputted from the transmitting trigger oscillator 1 is converted into a 64-bit signal subjected to various delays in the transmitting beamformer 2. This output signal forms four identical sound rays with different focal positions. For example, in the first trigger signal, s1 is phased to focus on zone 0.
A signal is output. In the second trigger signal, the 82 signal phased so as to focus on the zone 1 with the same sound ray is output, and similarly the 83 signal of the zone 2 and the 84 signal of the zone 3 are output. Each of the 81 to s4 signals is sequentially distributed by the scanner switch 3 to form a sound ray,
After being power amplified by the transmitting/receiving circuit 4, the ultrasonic probe array 5 converts the signal into an ultrasonic signal and transmits it into the subject. Ultrasonic signals reflected from a reflector within the subject are received by the ultrasound probe array 5 and converted into electrical signals. This received signal is amplified in the transmitter/receiver circuit 4 and restored to signals 81 to S4 by the scanner switch 3. The Sl signal is phased and added to the F1 signal having a focal position in zone 0 by an electronic focus circuit 6A. The S2 signal is phased and added to the signal having the focus position in zone 1 in the electronic focus circuit 6B, and is delayed by Δτt in the delay circuit 7B, and is output as a signal multiplied by Fz. S3 signal is electronic focus circuit 6C
The S4 signals are phased and summed by the electronic focus circuit 6D, and the delay circuits 7C and 7D add Δτ2. Δ
F3 signal after delay of τ3.

It is output as an F4 signal. The above E1 to F4 signals are successively switched and connected by the focal zone changeover switch 8, and are combined into one scanning line signal Fs. Since the F2 to F4 signals are each delayed by a different amount of delay, the F5 signal that is combined with the undelayed F1 signal has a delay between them at the joint of the signals, as illustrated in Figure 2. The portion of the received signal corresponding to the difference in amount appears twice. In FIG. 2, (a) is the waveform of the Fl signal, and (b) is the waveform of the F2 signal. (C) is a diagram showing the timing of switching the focal zone changeover switch 8, and (D) is a waveform in which the F1 signal and the F2 signal are synthesized by switching the focal zone changeover switch 8.

In the figure, as is clear, F! of (a)! Remarkable reflected waves a+, b1. c1. If you pay attention to dl, (b)
In the F2 signal of a2. which has been delayed by Δτ1. b2
+C2+d2.

Due to the switching control in (c), the Fs multiplied signal (q) of (d) is generated, but this Fs multiplied signal is a reflected wave b!.

The waveform b2 appears with a difference of Δτ1 between the spike noise e generated by switching the focal zone changeover switch 8. That is, in the section bl-b2, the original signal appears twice in succession. Although not shown, signals with similar waveforms also appear at the joints between zone 1 and zone 2, and between zone 2 and zone 3.

° Fs multiplied signal of this output, BPF like a normal device
9. Logarithmic amplifier 10. The signal is processed by the detector 11 and AD
A converter 12 converts it into a digital signal. The Fs multiplied signal shown in FIG. 2(d) converted into a digital signal is input to the read/write control logic circuit 13.

The data input to the read/write control logic circuit 13 is stored in the frame memory 21 according to the write address of the write address generation circuit 22.

The reading circuit 23 performs reading using one of the three types of reading methods specified by the HD and VD signals. The reading is performed as shown in FIG. 2 (E). That is, (d) 1. In the s signal, the section D+ up to the reflected wave pulse b1 and the section D3 after the reflected wave pulse b2 are read out from the frame memory 21 so as to restore the continuity in the original reflected wave signal, and the reflected wave pulse b1 In the interval D2 between the signal and the reflected wave pulse b2, reading is stopped by, for example, skipping a small interval while the address of the frame memory 21 is in progress, and the signal in that interval is not read out. Therefore, the spike noise e existing in between is also substantially removed without being read out. zone 1
and zone 2. Spike noise is similarly removed between zone 2 and zone 3. FIG. 4 is a diagram showing only the zone O and zone 1 portions of the contents of the frame memory 21 in a simplified manner. The figure shows a situation in which 01 is read from top to bottom, D2 is skipped, and D3 is read.

In other words, when writing, the data is read in one line at a time, and when reading, the overlapping part is not skipped, and after reading, the data may be sent directly to the CRT, or the read address may be controlled to perform scan conversion.

In either case, the read control circuit 23 is provided with a conversion table or an equivalent conversion function between the display address on the CRT screen and the address to be read from the frame memory 21. If FROM is used for this conversion table, the written result can be used for a linear scan DSC with vertical writing and horizontal reading, a linear scan DSC with vertical writing and vertical reading, and a read conversion type DSC for sector scan with conversion input. If the overlapping sections are in the same location, the same PROM can be used.

Note that the present invention is not limited to the above embodiments. For example, a circuit as shown in FIG. 5 may be used in place of the delay circuits 7B to 7D. In the figure, parts equivalent to those in FIG. 1 are given the same reference numerals.

In the figure, 31A is a BPF with a frequency bandwidth Δf1 whose center frequency is f, and 31B is a BPF whose center frequency is the same fO and a frequency bandwidth Δ“2.

31C is a BPF with a frequency bandwidth Δf3 at the center frequency [0
, 310 is the BP of the frequency bandwidth Δf4 with the center frequency "0"
It is F. Here, the frequency bandwidth has the following relationship.

ΔfI>Δf2>Δ[3>Δf4 The BPF is usually composed of an LC and causes a phase delay with respect to the input signal. If the delay time is the same, the narrower the frequency bandwidth, the longer the delay time, so the BPF
31A to 31D provide the same effect as the embodiment shown in FIG.

Further, the BPF may be added instead of replacing the delay circuit. Furthermore, although four electronic focus circuits and four delay circuits have been described, the number can be freely selected.

(Effects of the Invention) As described above in detail, according to the present invention, in the multi-stage focusing method, even if switching is performed at a high frequency stage, no white line appears on the final screen, and the practical effect is great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of spike noise removal, FIG. 3 is a schematic diagram of an embodiment of the internal configuration of a read control logic circuit and subsequent circuits, and FIG. FIG. 4 is a diagram showing the contents of the frame memory, and FIG. 5 is an explanatory diagram of another embodiment of the present invention. 2... Transmission beam former 3... Scanner switch 4... Transmission/reception circuit 5... Ultrasonic probe array 6A, 6B, 6C, 6D... Electronic focus circuit 78
．． 7C, 7D...Delay circuit 8...Focal zone changeover switch 9...3
1A, 31B, 31C, 31D...BPF12...
ΔD converter 13...Read/write control logic circuit 21...Frame memory 22...Write address generation circuit 23...Read control circuit 24...Synchronization signal generator 25...DA converter 27...・・CRT Patent applicant Yokogawa Medical Systems Corporation Figure 2

Claims (1)

[Claims] In an ultrasonic diagnostic system that has a video editing device that edits echo signals to receive echoes while switching the focus in order to obtain echo images with good resolution over the entire region, scanning line signals with different focuses are A plurality of electronic focus control means perform phasing and summation, a plurality of delay means give different delay times including zero to the output signals from the electronic focus control means, and a single output signal is switched between the output signals of the delay means. A switching means for combining the scan line data, a storage means for writing the combined scanning signal as it is, and a reading control from the storage means for restoring continuity by excluding signals in overlapping areas of the scanning signal. What is claimed is: 1. An ultrasonic diagnostic apparatus having a video editing device, characterized in that the ultrasound diagnostic apparatus is equipped with a readout control means for controlling the reading operation.