JPH05192335A - Ultrasonic diagnostic device with doppler function - Google Patents

Abstract

PURPOSE:To provide an ultrasonic diagnostic device with Doppler function having the function capable of making a white stripe noise unobtrusive when it is emerged. CONSTITUTION:The spectrum data outputted from a frequency analyzing part 7 for one analysis is stored in memories 211-21n, and a white strip noise component having a strong spectrum strength at a specified frequency is extracted by a self-correlator 22. The white stripe noise component is increased by k-times and subtracted from a spectrum data D, and on the basis of the subtracted spectrum data, Doppler display is conducted. Thus, a satisfactory Doppler display image never obstructed by a while stripe noise can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus with a Doppler function, and more particularly to an ultrasonic diagnostic apparatus with a Doppler function capable of apparently reducing so-called white stripe noise.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional ultrasonic diagnostic apparatus with a Doppler function. This ultrasonic diagnostic equipment with Doppler function 5
In 1, the Doppler demodulation unit 4 extracts the Doppler shift component from the echo signals obtained by the probe 2 and the analog signal processing unit 3. After that, the anti-aliasing filters 5i, 5
After passing through q, the Doppler signal is sent to the A / D converter 6i,
It is converted to digital data by 6q, and frequency analysis is performed by the FFT analysis unit 7 to obtain spectrum data D. Furthermore, a Doppler display image is generated from the spectrum data D,
The D / A converter 10 converts the video signal to a CRT1.
Doppler display is performed at 1. FIG. 6 illustrates the Doppler display screen. (B / Dmode) By the way, as shown in FIG. 6, the original Doppler display waveform s
So-called white stripe noise WN overlapping w
(White line that is parallel to the baseline and has high brightness) may appear. FIG. 7 shows spectrum data D1, D2, D3, D4 when white stripe noise WN appears.
For example. Spectrum data D1, D2, D3, D
No. 4 has a different time. As you can see from Figure 7,
The spectrum data D1, D2, D3, D4 includes a component (white stripe noise component) having a temporally stable spectrum intensity at a specific frequency. This appears as white stripe noise WN on the screen.

Since the white stripe noise component has a specific frequency, it is estimated that the noise source is a portion performing an extremely stable frequency operation such as a portion operated by a digital clock. Therefore, conventionally, in order to prevent the occurrence of white stripe noise, a portion operated by a digital clock or the like is shielded with a metal plate, or the ground around the entire system is strengthened.

[0004]

In the conventional ultrasonic diagnostic apparatus with a Doppler function, the white stripe noise is prevented from occurring as described above, but the white stripe noise is still changed only by changing the screw tightening strength. It was difficult to get rid of it.

Therefore, the present invention provides an ultrasonic diagnostic apparatus with a Doppler function, which has a function of preventing the occurrence of white stripe noise and making it inconspicuous when white stripe noise appears. To do.

[0006]

An ultrasonic diagnostic apparatus with a Doppler function according to the present invention is an ultrasonic diagnostic apparatus with a Doppler function for performing Doppler display based on spectrum data output from a frequency analyzing section. White stripe noise component extraction means for extracting a white stripe noise component having a temporally stable spectrum intensity at a specific frequency from the output spectrum data, and a spectrum for subtracting a predetermined correction amount from the spectrum data for the specific frequency. It is characterized in that it comprises a data correction means and a Doppler display means for performing a Doppler display based on the corrected spectrum data.

[0007]

In the ultrasonic diagnostic apparatus with Doppler function of the present invention,
The spectrum data output from the frequency analysis means is analyzed to extract a component having a temporally stable spectrum intensity at a specific frequency. Then, for the specific frequency, a predetermined correction amount is subtracted from the spectrum data output from the frequency analysis means. Since the component is a white stripe noise component, the corrected spectrum data has the white stripe noise component canceled by the correction amount. Therefore, if Doppler display is performed based on the corrected spectrum data, the white stripe noise WN becomes inconspicuous.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail based on the embodiments shown in the drawings. However, this does not limit the present invention. FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus 1 with a Doppler function according to an embodiment of the present invention.
In this ultrasonic diagnostic apparatus with Doppler function 1, the Doppler demodulation unit 4 extracts the Doppler shift component from the echo signals obtained by the probe 2 and the analog signal processing unit 3. Then, after passing through the anti-aliasing filters 5i and 5q, the Doppler signals are converted into digital data by the A / D converters 6i and 6q, and frequency analysis is performed by the FFT analysis unit 7 to obtain spectrum data D. Up to this point, it is the same as the conventional ultrasonic diagnostic apparatus with Doppler function 51 shown in FIG.

The spectrum data D output from the FFT analysis section 7 is supplied to the adder 8 and the changeover switch 20. The changeover switch 20 is an FFT
The analysis unit 7 switches each time the spectrum data D is output at a predetermined timing, and the spectrum data D1, D2, ...
, 21n are recorded.

The autocorrelator 22 is a memory 21 for one analysis.
Spectrum data D1, recorded in 1, ..., 21n
The correlation of D2, ... Is taken and the correlation value data H is output at a predetermined timing. The k-multiplier 23 multiplies the correlation value data H by a constant k designated by the keyboard 30 and outputs correction amount data kH. The adder 8 adds the spectrum data D and the correction amount data kH and outputs the corrected spectrum data S. The spectrum data D
And the correction amount data kH with respect to time is not a problem because the white stripe noise WN is temporally stable.

The DSC 9 generates a Doppler display image from the corrected spectrum data S, sends it to the CRT 11 via the D / A converter 10, and causes the CRT 11 to perform Doppler display.

FIG. 2 shows the timing at which the spectrum data D is output from the FFT analysis unit 7, the timing at which the spectrum data D is stored in the memory 211 for one analysis, and the output timing of the correlation value data H. Shows. In the example of FIG. 2, the spectrum data D1, ..., Dn for n times is analyzed and the memories 211 ,.
The data is stored in 1n intermittently. The autocorrelator 22 outputs the correlation value data H at the same timing as the spectrum data D output from the frequency analysis unit 7, and the new spectrum data D1, ..., Dn is stored in the analysis one-time memories 211 ,. The correlation value data H is updated only immediately after being set.

FIG. 3 shows a memory for one analysis 211 ,.
Spectrum data D1, ..., Dn stored in 1n
FIG. 6 is a waveform diagram showing the relationship among correlation value data H, correction amount data kH, and corrected spectrum data S. As understood from FIG. 3, if the value of the constant k is appropriately selected, the white stripe noise component can be almost canceled.

Therefore, while looking at the Doppler display screen, the value of the multiplier k designated by the keyboard 30 is changed so that the white stripe noise WN becomes inconspicuous. As shown in FIG. 4, the white stripe noise WN is not disturbed. You can get an image.

[0015]

According to the ultrasonic diagnostic apparatus with Doppler function of the present invention, even if white stripe noise appears on the Doppler display screen, it can be made inconspicuous.
A good Doppler display image that is not disturbed by white stripe noise can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus with a Doppler function according to an embodiment of the present invention.

FIG. 2 is a timing chart for outputting spectrum data and the like.

FIG. 3 is a waveform diagram of spectrum data and the like.

4 is an exemplary diagram of a Doppler display screen by the ultrasonic diagnostic apparatus with Doppler function of FIG.

FIG. 5 is a block diagram of an example of a conventional ultrasonic diagnostic apparatus with a Doppler function.

6 is an exemplary diagram of a Doppler display screen by the ultrasonic diagnostic apparatus with a Doppler function of FIG.

FIG. 7 is a waveform diagram of spectrum data.

[Explanation of symbols]

 1 Ultrasonic diagnostic device with Doppler function 2 Probe 4 Doppler demodulator 7 FFT analyzer D Spectrum data S Corrected spectrum data H Correlation value data kH Correction amount data 22 Autocorrelator 8 Adder 9 DSC 11 CRT 30 Keyboard 23 k Doubler 211, ..., 21n Memory for one analysis 20 Changeover switch WN White stripe noise

Claims (1)

[Claims] 1. An ultrasonic diagnostic apparatus with a Doppler function for performing a Doppler display based on spectrum data output from a frequency analysis means, wherein a spectrum intensity temporally stable at a specific frequency from the spectrum data output from the frequency analysis means. A white stripe noise component extracting means for extracting a white stripe noise component having
Spectrum data correction means for subtracting a predetermined correction amount from the spectrum data for the specific frequency;
An ultrasonic diagnostic apparatus with a Doppler function, comprising: a Doppler display unit that performs Doppler display based on corrected spectrum data.