KR101116988B1 - Method for frequency adjusting of tx signal and ultrasound system for the same - Google Patents

Abstract

The present invention relates to a method of varying the frequency of a TX signal according to the depth of an object and an ultrasonic system therefor. An ultrasound system according to the present invention includes a user input unit operable to receive input information for selecting a depth of an object; And forming a transmission signal having a different frequency according to the depth of the object based on the input information, converting the transmission signal into an ultrasound signal, transmitting the ultrasound signal to the object, and receiving an ultrasound echo signal reflected from the object, and a Doppler signal. And a signal acquiring unit operable to acquire continuously.

Description

Method of variable frequency of transmission signal and ultrasonic system for it {METHOD FOR FREQUENCY ADJUSTING OF TX SIGNAL AND ULTRASOUND SYSTEM FOR THE SAME}

The present invention relates to an ultrasound system, and more particularly, to a method of varying a frequency of a TX signal according to a depth of an object, and an ultrasound system therefor.

Ultrasound systems have non-invasive and non-destructive properties and are widely used in the medical field for obtaining information of an object inside a patient. Ultrasound systems are very important in the medical field because they can provide a doctor with a high-resolution image of a subject without the need for a surgical operation to directly incise and observe the patient.

The ultrasound system transmits an ultrasound signal to the object, receives an ultrasound signal reflected from the object (ie, an ultrasound echo signal), obtains image data corresponding to the intensity of the ultrasound echo signal, and generates a B mode image.

In addition, the ultrasound system obtains the Doppler signal of the ultrasound echo signal and forms a color Doppler image representing the movement of blood flow or the like based on the Doppler signal. The formed color Doppler image includes a color flow mapping image representing a velocity of blood flow and the like in a two-dimensional distribution and a power Doppler image representing a power of the Doppler signal in a two-dimensional distribution.

In general, ultrasound systems use transmit signals of the same frequency regardless of the depth of the object to form a color Doppler image. When the same transmission frequency is used, there is a problem that an inaccurate color Doppler image is formed because attenuation according to the depth of the object is not constant.

The present invention provides a method of varying the frequency of a TX signal according to the depth of an object to be observed and an ultrasonic system therefor.

An ultrasound system according to the present invention includes a user input unit operable to receive input information for selecting a depth of an object; And forming a transmission signal having a different frequency according to the depth of the object based on the input information, converting the transmission signal into an ultrasound signal, transmitting the ultrasound signal to the object, and receiving an ultrasound echo signal reflected from the object, and a Doppler signal. And a signal acquiring unit operable to acquire continuously.

In addition, the method for varying the transmission signal frequency according to the present invention, a) receiving input information for selecting the depth of the object; b) forming a transmission signal having a different frequency according to the depth of the object based on the input information; And c) converting the transmission signal into an ultrasound signal, transmitting the ultrasound signal to the object, receiving an ultrasound echo signal reflected from the object, and continuously obtaining a Doppler signal.

A computer-readable recording medium storing a program for performing a method of varying a transmission signal frequency, according to the present invention, the method comprising: a) receiving input information for selecting a depth of an object; b) forming a transmission signal having a different frequency according to the depth of the object based on the input information; And c) converting the transmission signal into an ultrasound signal, transmitting the ultrasound signal to the object, receiving an ultrasound echo signal reflected from the object, and continuously obtaining a Doppler signal.

According to the present invention, an optimal CW (continuous wave) image can be obtained at various depths of various applications and objects by using the most efficient transmission frequency according to the depth of the object. In addition, by synchronizing the pulse repetition frequency (TXR) and the transmission frequency (TX signal), the same size spectrum can be obtained in the same patient even when the transmission frequency is changed according to the depth of the object or when using a different probe. In addition, when the PRF is changed, a signal band displayed on the screen is changed, and a gain compensation for a change in noise density is thereby performed, thereby obtaining a uniform image even if the PRF is changed.

1 is a block diagram showing an ultrasound system according to an embodiment of the present invention.
Figure 2 is a block diagram showing the configuration of a signal acquisition unit according to an embodiment of the present invention.
3 is an exemplary view illustrating attenuation of a signal according to a frequency and a depth of an object according to an exemplary embodiment of the present invention.
Figure 4 is an exemplary view showing the conversion efficiency of the ultrasonic probe according to the frequency according to an embodiment of the present invention.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing the configuration of an ultrasonic system according to an embodiment of the present invention. Referring to FIG. 1, the ultrasound system 100 may include a user input unit 110, a signal acquirer 120, a processor 130, and a display 140.

The user input unit 110 receives user input information. In the present embodiment, the input information includes input information for selecting the depth of the object. The user input unit 110 may include a control panel, a mouse, a keyboard, and the like.

The signal acquisition unit 120 forms a transmission signal having a variable frequency according to the input information provided from the user input unit 110, converts the formed transmission frequency into an ultrasonic signal, transmits the ultrasound signal to the object, and reflects the ultrasound signal (that is, from the object). And an ultrasonic echo signal) to continuously obtain a Doppler signal. The signal acquisition unit 120 will be described in more detail with reference to FIG. 2.

2 is a block diagram showing a configuration of a signal acquisition unit according to an embodiment of the present invention. The signal acquisition unit 120 includes a clock forming unit 121, a transmission signal forming unit 122, an ultrasonic probe 123 including a plurality of transducer elements (not shown), an amplifier 124, A receiver focusing unit 125, a clock divider 126, a mixer 127, an analog to digital converter (ADC) 128, and a Doppler signal forming unit 129 are included.

The clock forming unit 121 forms a clock which is a pulse signal of a variable frequency according to the input information provided from the user input unit 110. In the present embodiment, the clock forming unit 121 sets a reference center frequency and sets a center frequency (hereinafter, referred to as a variable center frequency) by varying the reference center frequency according to the depth of the object based on the set reference center frequency. And a clock having a set variable center frequency. 3 is an exemplary view showing attenuation of a signal according to a frequency and a depth of an object according to an embodiment of the present invention, and FIG. 4 is an illustration showing conversion efficiency of an ultrasonic probe 123 according to a frequency according to an embodiment of the present invention. It is also. The ultrasound system 100 uses the center frequency as the frequency at which the efficiency of the probe 123 can be the highest. In FIG. 4, the conversion efficiency of the ultrasonic probe 123 is highest when the frequency of the transmission signal is 3 × 10 ¹⁶ Hz. Therefore, the clock forming unit 121 sets 3 × 10 ¹⁶ Hz as the reference center frequency of the clock, and if the depth of the object becomes deeper based on the set reference center frequency, that is, if the depth of the object is greater than or equal to a preset threshold, The first variable center frequency is set by decreasing the center frequency, and when the depth of the object becomes shallow, that is, when the depth of the object is less than the threshold value, the second variable center frequency is set by increasing the reference center frequency. The clock forming unit 121 forms a clock having a variable center frequency.

When the clock is provided from the clock forming unit 121, the transmission signal forming unit 122 continuously forms a transmission signal to be applied to each of the plurality of conversion elements in consideration of the position and focusing point of the conversion element. In the present embodiment, the transmission signal includes a transmission signal for obtaining a frame of a continuous wave (CW) mode image.

When the transmission signal is provided from the transmission signal forming unit 122, the ultrasound probe 123 converts the transmission signal into an ultrasound signal and transmits the ultrasound signal to the object, and receives the ultrasound echo signal reflected from the object to form a reception signal. In the CW mode, the conversion elements for transmitting the ultrasonic signal to the object and the conversion elements for receiving the ultrasonic echo signal reflected from the object are separated, and each of the conversion elements continuously performs only transmission and reception.

The amplifier 124 amplifies the received signal when the received signal is provided from the ultrasonic probe 123. The amplifier 124 may include a low noise amplifier (LNA).

When the reception focusing unit 125 receives the amplified reception signal from the amplification unit 124, the reception focusing unit 125 focuses the reception signal in consideration of the position and the focusing point of the conversion element to form the reception focusing signal.

The clock divider 126 forms a sampling frequency capable of optimizing the performance of the ADC 128 based on the clock formed by the clock generator 121. As an example, the clock divider 126 divides the clock formed by the clock forming unit 121 by an integer multiple to form a sampling frequency.

The mixer 127 demodulates the reception focus signal provided from the reception focusing unit 125 based on the sampling frequency provided from the clock divider 126 to form a mixing signal.

When the mixing signal is provided from the mixer 127, the ADC 128 analog-to-digital converts the mixing signal based on the sampling frequency provided from the clock divider 126 to form a digital signal.

When the digital signal is provided from the ADC 128, the Doppler signal forming unit 129 forms a Doppler signal using the digital signal. The Doppler signal includes power information and speed information. In addition, the Doppler signal forming unit 129 may perform various signal processing such as gain adjustment, filtering processing, etc. required to form the Doppler signal. In CW mode, pulse repetition frequency (PRF) represents the frequency band of the signal shown on the screen. That is, the PRF may be equal to the sampling rate or frequency of the analog to digital converter (ADC) 128. Gain is inversely proportional to the square root of the PRF. Accordingly, when the PRF (ie, ADC sampling rate) is increased by four times, the Doppler signal forming unit 129 may reduce the gain of the digital signal by 1/2 to adjust gain. Since an error may occur in a signal conversion process, the gain control method can be corrected through an experiment.

Referring back to FIG. 1, the processor 130 forms a color Doppler mode image by using a Doppler signal provided from the signal acquirer 120. The color Doppler mode image includes a power image representing power of the Doppler signal in a two-dimensional distribution and a velocity image representing speed of the Doppler signal in a two-dimensional distribution.

The display unit 140 displays the color Doppler mode image formed by the processor 130, that is, the power image and the speed image. The display unit 140 may include a cathode ray tube (CRT) display, a liquid crystal display (LCD), an organic light emitting diodes (OLED) display, or the like.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without setting the technical spirit or essential features. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all settings or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

In the above-described embodiment, the clock having a variable frequency is formed according to the input information received through the user input unit. In another embodiment, the depth of the object is automatically adjusted using an ultrasound image (for example, a B mode image). Can be detected, and a clock of a frequency varying according to the detected depth can be formed.

110: user input unit 120: signal acquisition unit
130 processor 140 display unit
121: clock forming unit 122: transmission signal forming unit
123: ultrasonic probe 124: amplifier
125: reception focusing unit 126: clock divider
127: mixer 128: ADC
129: Doppler signal forming unit

Claims (12)

As an ultrasound system,
A user input unit operable to receive input information for selecting a depth of an object; And
A transmission signal having a different frequency according to the depth of the object is formed based on the input information, the transmission signal is converted into an ultrasonic signal, transmitted to the object, and an ultrasonic echo signal reflected from the object is received to receive a Doppler signal. A signal acquiring unit operable to continuously acquire
. The method of claim 1, wherein the signal acquisition unit,
A clock forming unit configured to form a clock having a frequency varying according to a depth of an object based on the input information;
A transmission signal forming unit operable to continuously form the transmission signal based on the clock;
An ultrasound probe configured to convert the transmission signal into an ultrasound signal, transmit the ultrasound signal to an object, and receive an ultrasound echo signal reflected from the object to form a received signal;
An amplifying unit operable to amplify the received signal;
A reception focusing unit operable to focus the amplified reception signal to form a reception focusing signal;
A clock divider operative to multiply the clock to form a sampling frequency;
A mixer configured to demodulate the received focus signal based on the sampling frequency to form a mixing signal;
An analog to digital converter (ADC) operable to analog-to-digital convert the mixed signal based on the sampling frequency to form a digital signal; And
A Doppler signal forming unit operable to form a Doppler signal using the digital signal
. The apparatus of claim 2, wherein the clock forming unit sets a reference center frequency, sets the variable center frequency by varying the reference center frequency according to the depth of the object based on the reference center frequency, and sets the variable center frequency. And an ultrasonic system operative to form said clock. 4. The apparatus of claim 3, wherein the clock forming unit sets the first variable center frequency by decreasing the reference center frequency in proportion to the depth of the object when the depth of the object is greater than or equal to a preset threshold. And when the threshold value is less than the threshold, increases the reference center frequency in proportion to the depth of the object to set a second variable center frequency. The ultrasound system of claim 2, wherein the Doppler signal forming unit adjusts the gain of the Doppler signal to be inversely proportional to the square root of the sampling frequency. As the transmission signal frequency variable method,
a) receiving input information for selecting a depth of an object;
b) forming a transmission signal having a different frequency according to the depth of the object based on the input information; And
c) converting the transmission signal into an ultrasound signal, transmitting the ultrasound signal to the object, receiving an ultrasound echo signal reflected from the object, and continuously obtaining a Doppler signal
Transmission signal frequency variable method comprising a. The method of claim 6, wherein step b)
b1) forming a clock having a frequency varying according to the depth of the object based on the input information; And
b2) continuously forming the transmission signal based on the clock
Transmission signal frequency variable method comprising a. The method of claim 7, wherein the step b1),
b11) setting a reference center frequency;
b12) setting a variable center frequency by varying the reference center frequency according to the depth of the object based on the reference center frequency; And
b13) forming the clock having the variable center frequency
Transmission signal frequency variable method comprising a. The method of claim 8, wherein step b12)
Setting a first variable center frequency by decreasing the reference center frequency in proportion to the depth of the object when the depth of the object is greater than or equal to a preset threshold; And
And setting the second variable center frequency by increasing the reference center frequency in proportion to the depth of the object when the depth of the object is less than the threshold value. The method of claim 6, wherein step c)
c1) converting the transmission signal into an ultrasound signal and transmitting the ultrasound signal to an object, and receiving an ultrasound echo signal reflected from the object to form a reception signal;
c2) amplifying the received signal;
c3) focusing the amplified received signal to form a focused focus signal;
c4) forming a sampling frequency by integrally multiplying a clock of a frequency variable according to the depth of the object;
c5) demodulating the received focus signal based on the sampling frequency to form a mixing signal; And
c6) analog-to-digital converting the mixed signal based on the sampling frequency to form a digital signal; And
c7) forming a Doppler signal using the digital signal
Transmission signal frequency variable method comprising a. The method of claim 10, wherein step c7)
And adjusting the gain of the Doppler signal to be inversely proportional to the square root of the sampling frequency. A computer-readable recording medium storing a program for performing a method of varying a frequency of a transmission signal, the method comprising:
a) receiving input information for selecting a depth of an object;
b) forming a transmission signal having a different frequency according to the depth of the object based on the input information; And
c) converting the transmission signal into an ultrasound signal, transmitting the ultrasound signal to the object, receiving an ultrasound echo signal reflected from the object, and continuously obtaining a Doppler signal
A computer-readable recording medium storing a program for performing a method comprising a.

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