JPH0449954A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PURPOSE:To enable the obtaining of an image with high resolutions while providing a high S/N ratio by sampling a received signal at a certain timing to remove noise components of the received signal with an arithmetic processing performed on the signal using adjacent three data sampled continuously. CONSTITUTION:A received data equivalent to one scan line of an ultrasonic beam digitized is samaled at a certain timing to be turned to a continuous digitized reception data, and adjacent sampled data A, B and C are stored and held by data memory holding means 11a, 11b and 11c respectively. A digital filter computation means 11d inputs memory data A, B and C-read out of the data memory holding means 11a, 11b and 11c to compute. In other words, a part of the adjacent data are added to the data having noises to be divided in two so that noise components are removed to make a correction value data closer to a true data. Thereafter, the same arithmetic processing is performed for all of one scan of received data to obtain a correction value closer to the true data. Then, an ultrasonic tomographic image with a higher S/N ratio is displayed on a monitor screen 9 through a scan conversion means 8.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention emits ultrasonic waves from an ultrasonic probe toward a subject, and a display device is illuminated by the received signal of the ultrasonic waves reflected from the subject. The present invention relates to an ultrasonic diagnostic apparatus that displays an ultrasonic tomographic image of a specimen.

BACKGROUND OF THE INVENTION Conventionally, this type of ultrasonic diagnostic equipment, as shown in Fig. 3,
The ultrasonic probe 2 is energized by the transmitter 1, and an ultrasonic beam is emitted from the ultrasonic probe 2 into a living body as a subject.

The reflected waves generated from this living body due to the difference in acoustic impedance are received by the receiving unit 3 via the ultrasound probe 2,
After being amplified by the amplifier 4, it is detected by the detector 5.

The detected signal is an analog digital signal (hereinafter referred to as A
/D converter) 6 converts it into a digital signal,
After the received signal is averaged by the signal processing means 7,
The scan conversion means 8 scan-converts the signal into a standard television system signal, and displays it on a monitor 9 as a tomographic image.

The signal processing means 7 in the above-mentioned conventional ultrasonic diagnostic apparatus includes:
data storage holding means 7a and 7b for holding received data;
It is roughly composed of a data adder 7c and a divider 7d.

That is, as shown in FIG. 4(A), the received signal corresponding to one scanning line of the ultrasonic beam is sampled at a certain appropriate timing as shown as the input data in FIG. 4(CB). A, B.

This is continuous received data that has been digitized like C and D.

Input data A is stored in the memory holding means 7a, input data B is stored in the memory holding means 7b, and these two received data A and B are added together by an adder 7C. This added received data A+B is divided by half by a divider 7d, and as shown as output data in FIG. 4(B),
A received data signal of (A+B)/2 is obtained and becomes display data.

In other words, the image quality of tomographic images is improved by repeatedly performing a simple averaging process on two adjacent pieces of data to reduce irregular noise components called speckle noise in ultrasound tomographic images. We are trying to

Problems to be Solved by the Invention However, with the above-mentioned conventional ultrasonic diagnostic apparatus, although it is possible to reduce noise such as speckle noise by simply averaging adjacent data, the received signal components also Since it is averaged, the received signal level is no longer the original one, and the fidelity of the received signal is impaired. In other words, S/
There is a problem in that it is difficult to obtain a received signal with a high N value and to depict an accurate tomographic image.

The present invention solves these conventional problems by maintaining the fidelity of the received signal, reducing noise components such as speckle noise, obtaining a high S/N ratio, and improving resolution. The object of the present invention is to obtain an excellent ultrasonic diagnostic apparatus capable of depicting high-quality ultrasonic tomographic images.

Means for Solving the Problems In order to achieve the above objects, the present invention includes an ultrasonic probe that emits ultrasonic waves toward a subject, and converts a received signal by a reflected wave from the subject into a digital signal. analog/
a digital converter, a memory holding means that samples the received signal at a certain timing and stores and holds three successive adjacent sampling data, and performs arithmetic processing using the data read from each of the memory holding means,
The apparatus includes a calculation means for removing noise components contained in the received signal, and a scan conversion means for displaying an ultrasonic tomographic image on a monitor based on an output signal from the calculation means.

Effect of the Invention With the above-described configuration, the present invention maintains the fidelity of the received signal, reduces noise components such as speckle noise, obtains a high S/N ratio, and produces good ultrasonic tomography with high resolution. Can draw images.

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, elements similar to those of the conventional device shown in FIG. 3 are given the same reference numerals, and their explanations will be omitted. 11th
! 1, 11 is a signal processing means which is a main part of the ultrasonic diagnostic apparatus of the present invention, and this signal processing means 11 includes three data storage means 11a.

11b and 11c and a digital filter calculation means 11d.

Each of the data storage and holding means 11a, llb, 11c is
Similar to the conventional device shown in FIG. 3, the ultrasonic probe 2
The continuous digitized received data in one scanning line direction of the ultrasound beam obtained from the ultrasound beam is sampled, and each adjacent sampling data is temporarily stored and held.

Further, the digital filter calculation means 11d performs calculation processing of a nonlinear digital filter, and although not shown, it includes a subtracter that calculates the difference between each data, and a comparator that compares the subtraction result with a predetermined value. , an adder and a divider that perform data addition and division based on the comparison results.

Next, the operation of the above embodiment will be explained based on FIGS. 2(A) to 2(B). As shown in No. 21r(A), the received data corresponding to one scanning line of the digitized ultrasound beam are, for example, A, B, and C.

D, E, F... Each of the received data is shown with an appropriate fluctuating amplitude as shown in FIG. 2(B).

Part of the data is sampled at a certain timing as shown as the 21st (C) input data, and A, B, C
, D, E, F, . . . are digitized continuous received data. Then, from each sampled data, three data A, B, C
are once input to the data storage/holding means 11a, llb, llc and stored and held in sequence.

The digital filter calculation means lid inputs the stored data A, B, and C read out from the data storage holding means 11a, llb, and llc, and inputs the stored data A-B-Δ^8°C-A-ΔC1
If the subtracted value of l is found and its absolute value is greater than or equal to the predetermined threshold ΔX, and the values of Δ^β and 8CB are of the same sign, then data B is data with a lot of speckle noise, etc. It is determined that there is. In other words, it can be seen that the point f3x in FIG. 2(B) is data with a lot of noise.

Therefore, for data B, a correction calculation is performed using the following equation: B=(A/20B+C/2)/2 (1). In other words, the presence or absence of a noise component is determined from three consecutive adjacent data,
For noisy data, remove the noise component by adding part of the adjacent data and dividing it by 1. The correction value data should be close to the data of .

Below, similar calculation processing is performed on all received data A, B, C, D, E, F, etc. for one scanning line to remove noise components and obtain correction values close to the true data. After that, an ultrasonic tomographic image with a high S/N ratio is displayed on a monitor screen 9 via a scan conversion means 8.

In the above embodiment, the digital arithmetic unit 11d that performs data arithmetic operations uses a read-only memory (ROM') to simplify the circuit, and includes subtracters, comparators, adders, and dividers. etc., and we decided to simply add the data and divide the data into 1 part, but if necessary, we could change the divisor, change the ratio of adjacent data to be added, or change the multiplier or exponent operation. Needless to say, it is okay.

Effects of the Invention As is clear from the above embodiments, the present invention comprises an ultrasonic probe that emits ultrasonic waves toward a subject, and an analog/digital probe that converts a received signal by a reflected wave from the subject into a digital signal. a converter, a memory holding means that samples the received signal at a certain timing and stores and holds each of three successive adjacent sampling data, and performs arithmetic processing using the data consecutively outputted from each of the storage holding means, Since the apparatus is equipped with a calculation means for removing noise components contained in the received signal and a scan conversion means for displaying an ultrasonic tomographic image on a monitor based on the output signal from the calculation means, the fidelity of the received signal can be maintained. In addition, it is possible to reduce noise components such as speckle noise, obtain a high S/N ratio, and depict a good ultrasonic tomographic image with high resolution.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a signal processing means which is a main part of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, and FIG. 2 (A)
, (B), and (C) are diagrams showing the relative relationship of each data in the device of the present invention, (A) is a diagram showing the arrangement of data for one scanning line of an ultrasound beam, and (B) is a diagram showing the arrangement of data for one scanning line of an ultrasound beam. (C) is a diagram showing the arrangement of input data and each data processed by arithmetic processing. FIG. 3 is a schematic block diagram of a conventional ultrasonic diagnostic device. FIGS. 4 (A) and (B) is a diagram showing the relative relationship of each data in the conventional device of FIG.
A) is a diagram showing the arrangement of data for a scanning line of an ultrasound beam, and (B) is a diagram showing the arrangement of input data and each data subjected to calculation processing. 6... A/D converter, 8... Scan conversion means, 9...
・Monitor, 11... signal processing means, lla~llc・
...Data storage holding means, lid...Digital filter calculation means. Figure Figure Figure Figure (A) One run score - (C) Figure (A> (B) Correction data

Claims (1)

[Claims] An ultrasonic probe that emits ultrasonic waves toward a subject, an analog/digital converter that converts a received signal by a reflected wave from the subject into a digital signal, and an analog/digital converter that samples the received signal at a certain timing and continuously a memory holding means for storing and holding three adjacent sampling data respectively; a calculating means for performing arithmetic processing using the data read from each of the memory holding means and removing noise components contained in the received signal; An ultrasonic diagnostic apparatus comprising scan conversion means for displaying an ultrasonic tomographic image on a monitor based on an output signal from the calculation means.