JPH02200256A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To prevent the generation of a noise due to interlace scan as much as possible and to obtain a satisfactory ultrasonic picture smoothly connected by taking in data before one field for a raster out of field scan when there is no motion and taking in the data from a line interpolation circuit when there is the motion. CONSTITUTION:When the absence of the motion is decided based on the detected result of a motion detection circuit 20, a detection signal s0 is not outputted. In such a case, ODD field data #1, #3, #5... before one field stored in a field memory 5 are inputted to a multiplexer 6 and synthesized by this multiplexer 6. On the other hand, when the detection signal s0 is obtained from the motion detection circuit 20, interpolation data are inputted from a line interpolation circuit 32 to a multiplexer 7 and even when there is the motion, the ODD field data and the line interpolation data can be obtained. Thus, one ultrasonic frame goes to be the almost same condition as that of the non-interlace scan and the satisfactory ultrasonic picture can be obtained.

Description

[Detailed description of the invention]

"Purpose of the invention" (Industrial application field) The present invention transmits and receives ultrasound waves from an ultrasound probe to a subject, and converts the received signals obtained thereby into digital signals using an A/D converter. The present invention relates to an ultrasonic diagnostic apparatus that converts the data, writes this data into a frame memory, performs TV scanning, and displays an ultrasonic tomographic image on a display system. Diagnosis is provided using scientific information, information on movement of organs in the living body, such as M-mode images, and functional information associated with the movement of moving objects within the living body using the Doppler effect, such as blood flow imaging. In addition, a typical example of the scanning force of ultrasound on the inside of a living body is electronic scanning mechanical scanning.Here, we will explain the electronic scanning method.In other words, multiple ultrasound transducers are used together. In the case of linear electronic scanning using an array-type ultrasonic probe made of This is a method of transmitting ultrasonic beams, for example, by sequentially shifting the pitch by one oscillator and excitation so that the position of one unit of element changes in turn, the transmitting point of the ultrasonic beam can be adjusted. This is a method of electronically shifting the position.Then, in order to focus the ultrasonic beam as a beam, the excited ultrasonic transducers are divided into two types: one located at the center of the beam, and one located at the side. The timing of the excitation is shifted, and the reflected ultrasound is focused (electronic focusing) by using the phase difference between the sound waves generated by the ultrasound transducer.Then, the reflected ultrasound is focused by the same transducer that was excited. The waves are received and converted into electrical signals, and the echo information from each transmitted and received wave is formed, for example, as a tomographic image, and the image is displayed on a cathode ray tube, etc. In addition, in the case of sector scanning, one unit of excited ultrasonic transducer The excitation timing of each transducer is changed according to the desired direction so that the transmission direction of the ultrasonic beam for the group sequentially changes in a fan shape every one pulse of the ultrasonic beam. is basically the same as the linear electronic scanning described above.In addition to the linear and sector electronic scanning described above, ultrasonic scanning is also possible by attaching a transducer (probe) to the scanning mechanism and moving the scanning mechanism. There is also mechanical scanning that performs. On the other hand, in addition to B-mode images in which signals based on ultrasonic transmission and reception are combined to form a tomographic image, M-mode images using fixed scanning in the same direction are typical of imaging methods. This represents the temporal change in the ultrasonic wave transmitting/receiving site, and is particularly suitable for diagnosing moving organs such as the heart. Further, the ultrasonic Doppler method, of which blood flow imaging is a typical example, is a method of obtaining functional information accompanying the movement of a moving object within a living body and visualizing it, and this will be described in detail below. That is, the ultrasonic Doppler method utilizes the ultrasonic Doppler effect in which when an ultrasonic wave is reflected by a moving object, the frequency of the reflected wave shifts in proportion to the moving speed of the object. Specifically, if an ultrasonic rate pulse (or continuous wave) is transmitted into a living body and the frequency shift due to the Doppler effect is obtained from the phase change of the reflected wave echo, the Motion information about moving objects can be obtained. According to this, it is possible to know the state of blood flow such as the direction of blood flow at a certain position in the living body, the state of the flow (disturbed or regular), the flow pattern, the velocity value, etc. Next, the device will be explained. That is, in order to obtain blood flow information from ultrasonic echoes, ultrasonic pulses are repeatedly transmitted a predetermined number of times in a certain predetermined direction, and phase information is extracted by phase-detecting the received echoes. This signal is digitized and passed through a digital filter to remove non-moving or slow-moving components, ie, clubber components. Then, the signal that has passed through the filter is subjected to frequency analysis. Here, by performing the above-described series of processes while scanning the ultrasound beam from one side to the other in correspondence with the sector scan screen, information on blood flow distributed two-dimensionally can be detected. And the aforementioned blood flow direction 4
and blood flow information such as a two-dimensional blood flow velocity image showing velocity,
The B-mode image and M-mode image obtained with another system are superimposed and synthesized using a DSC (digital scan converter), and the T
It can be displayed on a V monitor. Next, Figure 4 shows ultrasound image 1 obtained by conventional ultrasound scanning.
It is a diagram showing ultrasonic rasters #l to #N forming a frame. Conventionally, ultrasonic scanning has been performed as a non-interlace scan in which raster #1 is sequentially scanned to raster #N as shown in FIG. For this reason, it takes a long time for one frame period, and the phenomenon caused by the time difference between rusks that occurs when displaying a fast-moving organ such as the heart, that is, the shape of the heart valve may become distorted. The movement appears to be reversed. The reason for this can be explained as follows. That is, if the ultrasonic transmission/reception cycle is T and the number of rasters is N, it takes NT time to generate one frame of image. That is, N −258, T −2
50p sec becomes NT-84-sec. On the other hand, the movement of the heart valves is faster in abnormal cases and newborns, resulting in poor temporal resolution and, as mentioned above, the problem that images between frames are not connected smoothly in time. (Problem IA to be Solved by the Invention) On the other hand, there is also a method of employing interlace scanning in order to make the frame image smooth. This interlaced scan scans the ODD field (rasters #1, #3...#N), and then the EVE
This is a method of scanning N fields (rasters #2, #4, etc.). According to this, since one frame is composed of two fields, the image becomes smoother than the conventional image. However, when an organ in a single field image is in motion, such as a heart, the raster in the gap where field scanning is not performed results in an image containing jagged noise, making the entire image look ugly. Therefore, the purpose of the present invention is to provide an ultrasonic wave that can prevent the generation of noise due to interlace scanning as much as possible even when there is movement, increase the ultrasonic frame speed, and obtain smoothly connected good ultrasonic images. The objective is to provide diagnostic equipment. [Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems and achieve the objects, the present invention takes the following measures. That is, the present invention transmits and receives ultrasonic waves from an ultrasonic probe to a subject, converts the received signal obtained thereby into a digital signal using an A/D converter, and uses this data as an ODD in ultrasonic scanning. In an ultrasonic diagnostic apparatus that writes data to each field memory every EVEN field scan, reads out data from each field memory, and displays the data on a display system, data from the A/D converter is stored in the field memory. A motion detection circuit that determines that there is movement when the difference data obtained by subtracting the data before the frame exceeds a predetermined value, and a raster that is not present in the field scan when there is movement is created by interpolating the rasters before and after this field scan. An inter-line interpolation circuit,
Based on the result of the motion detection circuit, if there is no movement, the raster not included in the field scan takes in data from one field before, and if there is movement, takes in the data from the line-to-line interpolation circuit. It is equipped with the following. (Effects) By taking such measures, the following effects will be exhibited. If there is no movement, data from one field before is used for rasters that are not in the field scan, and if there is movement, data for rasters that are not in the field scan is created by interpolating the rasters before and after the scan. Therefore, one frame of ultrasonic waves is in almost the same state as a non-interlace scan state, and the jagged noise during interlace scan can be removed and a good ultrasound image can be obtained. In addition, since the ultrasound scanning speed is interscanning speed, the number of ultrasound frames is approximately twice that of conventional non-incremental scanning, and even when measuring and displaying fast-moving organs, the number of ultrasound frames is It can be observed that the images appear to be connected smoothly. (Example) Fig. 1 is a schematic configuration diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention, Fig. 2 is a diagram showing a detailed configuration of a motion detection circuit, and Fig. 3 (a) is a diagram showing an embodiment of the ultrasonic diagnostic apparatus according to the present invention. FIG. 3(b) is a diagram showing an ODD field and an EVEN field in one ultrasonic frame. The ultrasonic diagnostic apparatus will be explained below with reference to the drawings. The ultrasonic probe l is driven to transmit by a wave transmitting/receiving circuit 2,
As a result, ultrasonic pulses are transmitted from the transducer of the ultrasonic probe l to the living body. Then, the reflected ultrasonic waves are received by the ultrasonic probe l and the wave transmitting/receiving circuit 2. Further A
/D converter 3 converts the ODD fields (#l, #3 .
Data for one field (#5...#N) is written into the field memory 4. Next, the EVEN field (#2.#
4. #6...) data is written. That is, during this period, the OD
The data in the D field is read out and stored in the field memory 5.
written to. Then, EVEN field data is input from field memory 4 to multiplexer B.
Also, ODD field data is input from the field memory 5. On the other hand, during the above period, the motion detection circuit 20 is connected to the A/D converter 3.
The data of the ODD field from the field memory 5 and the data of the ODD field one frame before are input from the field memory 5. In the motion detection circuit 20, processing as shown in FIG. 2 is performed. That is, digital LP
The current ODD field data and one frame previous ODD field data inputted to F21 and F22, respectively, are filtered and latched by latch circuits 23 and 24. Then, the current ODD is determined by the absolute value circuit 25.
The ODD field data of one frame before is subtracted from the field data, and the difference data is converted into an absolute value. Then, the output from the absolute value circuit 25 is compared with the threshold level TH by the comparator 2B. That is, when the output P output from the absolute value circuit 25 exceeds the threshold level TH, it is determined that there is movement and the detection signal SO is output to the multiplexer 7 as a control means. Here, if it is determined that there is no movement based on the detection result of the motion detection circuit 20, the detection signal SO is not output. In this case, when EVEN field data is inputted to the multiplexer 6 from the field memory 4 described above, at the same time, raster data not included in the EVEN field scanning, that is, ODD field data #l of the previous field stored in the field memory 5, #3. #5...
- Data is input to multiplexer G and synthesized by this multiplexer 6. Therefore, when there is no movement, the ODD field data of one field before is used during the EvEN field scanning period, and the EVEN field data of one field before is used during the ODD field scanning period, as if it were a non-interlace scan. The images will look like they are connected smoothly. On the other hand, when the detection signal SO is obtained from the motion detection circuit 20, the detection signal SO is input to the multiplexer 7. Further, the ODD field data from the field memory 5 is inputted to the multiplexer via the multiplexer 8. Furthermore, the ODD stored in the filter memory 5
Regarding the field data, one line of data, that is, one raster, is written in the one line memory 31, and the previous raster data and current raster data of one line from the one line memory 31 are input to the interline interpolation circuit 32. As a result, both the preceding and following raster data are captured and interpolated data is created. That is, the raster that is not present during the ODD field scanning period, that is, the EVEN field (#2
．． #4...) The interpolated data is used as the data. The interpolation data from the interline interpolation circuit 32 is input to the multiplexer 7, and even when there is movement, the ODD field data and the interpolation data between the lines are combined by the multiplexer 7. Furthermore, the coordinates of the data are transformed by the coordinate transformation and interpolation circuit 9, subjected to interpolation processing, and written into the frame memory IO. Furthermore, data is read out from the frame memory IO and displayed on the TV display section 11. In this way, according to this embodiment, when there is no movement, the data from one field before is used for rasters that are not included in the field scan, and when there is movement, the data from before and after the field scan is used for the rasters that are not included in the field scan. Since the data is created by interpolation processing from the raster, one frame of ultrasonic waves is almost the same as the non-interlace scan state, and the jagged noise that occurs during interlace scan can be removed.
Good ultrasound images can be obtained. In addition, since the ultrasound scan speed is an interlace scan speed, the number of ultrasound frames is approximately twice that of conventional non-interlace scans, and even when measuring and displaying fast-moving organs, the number of ultrasound frames is It can be observed that the images appear to be connected smoothly. Note that the present invention is not limited to the embodiments described above. For example, the motion detection circuit may use the sum or variance of differences between several frames in addition to the difference between one frame. Interpolation between lines during motion detection can also be improved by using an interpolation filter for several lines instead of between two lines, and by changing the cut-off frequency of the filter depending on the degree of motion. It is also conceivable to take a step forward and add the data of the previous field and the interpolated data between the same fields in accordance with the degree of movement. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

【Effect of the invention】

According to the present invention, there is provided a motion detection circuit that determines that there is movement when the difference data obtained by subtracting the data from the A/D converter and the data of one frame before stored in the field memory exceeds a predetermined value; In a certain case, a raster that is not in the field scan is created by an interline interpolation circuit that interpolates the rasters before and after this field scan, and if there is no movement based on the results of the motion detection circuit, a raster that is not in the field scan is created by one field. Since it is equipped with a control means that captures previous data and captures data from the interline interpolation circuit when there is movement, one frame of ultrasonic waves is in almost the same state as a non-interlace scan state, and the interpolation circuit is It is possible to remove jagged noise during non-scanning and obtain good ultrasound images. In addition, the ultrasound scan speed is
Since it is an interlace scan speed, the number of ultrasonic frames is approximately twice that of conventional non-interlace scan.
Even when measuring and displaying fast-moving organs, it is possible to provide an ultrasonic diagnostic apparatus that allows images to be observed as if they are smoothly connected between frames.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing an ultrasonic diagnostic apparatus according to the present invention, FIG. 2 is a diagram showing a detailed circuit of the motion detection circuit shown in FIG. 1, and FIG. 3 is an inkless scan to which the present invention is applied. FIG. 4 is a schematic diagram showing a non-interlace scan. l... Ultrasonic probe, 2... Transmission/reception circuit, 3...
A/D converter, 4.5...Field memory, 6.7
. . . Multi-brake 2, 9 . . . Coordinate transformation and interpolation circuit, IO . . . Frame memory, 11 . . . TV display unit, 20 . 23, 24...Latch circuit, 25...Absolute value circuit,
2G...Comparator, 31...1 line memory,
32...Line interpolation circuit. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] Ultrasonic waves are transmitted and received from the ultrasound probe to the subject, and the received signal obtained by this is converted into a digital signal by an A/D converter, and this data is used as ODD in ultrasound scanning.
, in an ultrasonic diagnostic apparatus that writes data to each field memory every time an EVEN field is scanned, reads out data from each field memory, and displays the data on a display system.
a motion detection circuit that determines that there is movement when the difference data obtained by subtracting the data from the converter and the data of one frame before stored in the field memory exceeds a predetermined value; The raster is created by an interline interpolation circuit that interpolates the rasters before and after this field scan, and based on the results of the motion detection circuit, if there is no movement, the raster that is not in the field scan takes in the data from one field before, and An ultrasonic diagnostic apparatus characterized by comprising: control means for taking in data from the interline interpolation circuit in some cases.