ULTRASOUND SYSTEM AND CLUSTER FILTERING METHOD THEREOF

• US 20140316274A1
• Filed: 04/22/2014
• Published: 10/23/2014
• Est. Priority Date: 04/22/2013
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., Sogang University Research Foundation
• Original Assignee: Samsung Electronics Co. Ltd., Sogang University Industry-University Cooperation Foundation
• Inventors: KOH, Hyun-woo, YOO, Yang-mo, KIM, Young-tae, SHIM, Hwan, LIM, Hyung-joon, YEO, Sun-mi, LEE, Woo-youl
• Granted Patent: US 10,456,115 B2
• Time in Patent Office: Days
• US Class Current: 600/453
• CPC Class Codes: A61B 5/1128 using image analysis A61B5/1127 takes precedence
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/488 involving Doppler signals
• CPC Class Codes: A61B 8/5269 involving detection or reduction of artifacts for image enhancement algorithms G06T5/00
• CPC Class Codes: G01S 15/8977 using special techniques for image reconstruction, e.g. FFT, geometrical transformations, spatial deconvolution, time deconvolution
• CPC Class Codes: G01S 15/8981 Discriminating between fixed and moving objects or between objects moving at different speeds, e.g. wall clutter filter
• CPC Class Codes: G05B 2219/40326 Singular value decomposition
• CPC Class Codes: G06T 2207/20112 Image segmentation details
• CPC Class Codes: G06T 2207/20201 Motion blur correction
• CPC Class Codes: G06T 7/00 Image analysis
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/10 Segmentation; Edge detection motion-based segmentation G06T7/215
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/215 Motion-based segmentation
• CPC Class Codes: G06T 7/60 Analysis of geometric attributes
• CPC Class Codes: G06T 9/20 Contour coding, e.g. using detection of edges

Abstract

An ultrasound system and a clutter filtering method thereof are provided. The clutter filtering method includes: transmitting an ultrasound signal to an object; receiving a reflection signal reflected from the object; performing a singular value decomposition (SVD) on a plurality of doppler signals constituting the reflection signal; dividing a representation of the object into a plurality of regions according to a result of performing the SVD; determining cutoff frequencies of the plurality of regions according to different methods; and performing clutter filtering on the plurality of regions by using the determined cutoff frequencies.

Claims

1. A clutter filtering method of an ultrasound system, comprising:

transmitting an ultrasound signal to an object;

receiving a reflection signal reflected from the object;

performing a singular value decomposition (SVD) on a plurality of doppler signals constituting the reflection signal;

dividing a representation of the object into a plurality of regions according to a result of performing the SVD;

determining cutoff frequencies of the plurality of regions according to different methods; and

performing clutter filtering on the plurality of regions by using the determined cutoff frequencies.

2. The clutter filtering method of claim 1, wherein the dividing the representation of the object into the plurality of regions comprises:

dividing the representation of the object into a tissue region and a flow region.

3. The clutter filtering method of claim 2, wherein the determining of the cutoff frequencies of the plurality of regions according to the different methods comprises:

applying a tissue acceleration factor (TAF) method to the tissue region and applying the result of performing the SVD to the flow region to determine the cutoff frequencies of the tissue region and the flow region.

4. The clutter filtering method of claim 3, wherein the performing of the SVD comprises:

forming a matrix defining a characteristic of the object by using the plurality of doppler signals;

performing the SVD on the matrix to form a plurality of indexes for representing an ultrasound image of the object; and

calculating an average frequency and a power of each of the plurality of indexes.

5. The clutter filtering method of claim 4, wherein the dividing the representation of the object into the plurality of regions further comprises:

determining one of the plurality of regions, which has one of the plurality of indexes having an average frequency higher than a preset frequency and a power lower than a preset power, as the flow region; and

determining the other regions among the plurality of regions as the tissue region.

6. The clutter filtering method of claim 5, wherein the determining of the cutoff frequencies of the plurality of regions according to the different methods further comprises:

estimating a frequency of a doppler signal corresponding to the tissue region by using an autocorrelation method, multiplying the estimated frequency by a preset coefficient, and adding a result of the multiplying to the frequency to determine the cutoff frequency of the tissue region; and

estimating a clutter signal from the flow region according to the result of performing the SVD and, if an average frequency of the estimated clutter signal is lower than or equal to a preset frequency, determining the average frequency as the cutoff frequency of the flow region.

7. An ultrasound system comprising:

an ultrasound transceiver configured to transmit an ultrasound signal to an object and receive a reflection signal reflected from the object;

a controller configured to perform a singular value decomposition (SVD) on a plurality of doppler signals constituting the reflection signal, divide a representation of the object into a plurality of regions according to a result of performing the SVD, determine cutoff frequencies of the plurality of regions according to different methods, and perform clutter filtering on the plurality of regions by using the determined cutoff frequencies; and

a display unit configured to display a signal on which the clutter filtering is performed, as an image.

8. The ultrasound system of claim 7, wherein when the controller divides the representation of the object into the plurality of regions, the controller divides the representation of the object into a tissue region and a flow region.

9. The ultrasound system of claim 8, wherein when the controller determines the cutoff frequencies, the controller applies a tissue acceleration factor (TAF) method to the tissue region and the result of performing the SVD to the flow region to determine the cutoff frequencies of the tissue region and the flow region, respectively.

10. The ultrasound system of claim 9, wherein when the controller performs the SVD, the controller forms a matrix defining a characteristic of the object by using the plurality of doppler signals, performs the SVD on the matrix to form a plurality of indexes for representing an ultrasound image of the object, and calculates an average frequency and a power of each of the plurality of indexes.

11. The ultrasound system of claim 10, wherein when the controller divides the representation of the object into the plurality of regions, the controller determines one of the plurality of regions, which has one of the plurality of indexes having an average frequency higher than a preset frequency and a power lower than a preset power, as the flow region, and determines the other regions among the plurality of regions as the tissue region.

12. The ultrasound system of claim 11, wherein when the controller determines the cutoff frequencies of the plurality of regions according to the different methods, the controller estimates a frequency of a doppler signal corresponding to the tissue region by using an autocorrelation method, multiplies the estimated frequency and a preset coefficient to generate a multiplication result value, and adds the multiplication result value to the frequency in order to determine the cutoff frequency of the tissue region, and estimates a clutter signal from the flow region according to the result of performing the SVD and, if an average frequency of the estimated clutter signal is lower than or equal to a preset frequency, determines the average frequency as the cutoff frequency of the flow region.

13. An ultrasound apparatus comprising:

an ultrasound transceiver configured to transmit an ultrasound signal to an object and receive a reflection signal reflected from the object;

a controller configured to divide a representation of the object into a first region where flow exists and a second region where flow does not exist according to the reflection signal, select different clutter eliminating filters to eliminate clutter in the first region and the second region, respectively, and perform clutter filtering on a signal comprising the first region and the second region using the selected clutter eliminating filters to output a clutter filtered signal; and

a display configured to display the clutter filtered signal as an image.

14. The ultrasound apparatus of claim 13, wherein the controller is configured to select the different clutter eliminating filters based on cutoff frequencies of the first and second regions.

15. The ultrasound apparatus of claim 14, wherein the controller is configured to use a first method to determine the cutoff frequency of the first region and a second method different from the first method to determine the cutoff frequency of the second region.

16. The ultrasound apparatus of claim 15, wherein the reflection signal comprises a plurality of doppler signals, and the controller is configured to perform a singular value decomposition (SVD) on the plurality of doppler signals and divide the representation of the object into the first region and the second region according to a result of the SVD.

17. The ultrasound apparatus of claim 16, wherein the second method comprises a tissue acceleration factor (TAF) method.

18. The ultrasound apparatus of claim 17, wherein the controller is configured to determine a signal having a highest power among a plurality of signals as a clutter signal, and determine signals having lower powers than the clutter signal as flow and noise signals.

19. The ultrasound apparatus of claim 13, wherein the display is configured to display the image as a 2-dimensional (2D) commercial film (CF) image.

20. The ultrasound apparatus of claim 13, wherein the controller is configured to determine the second region as a tissue region.