An ultrasonic imaging method with a probe center frequency intensity coefficient weighting

Abstract

This invention discloses an ultrasound imaging method weighted by the center frequency intensity coefficient of the probe. First, the echo signal received by the ultrasound probe is acquired, and the position and intensity of the echo signal corresponding to each pixel are determined based on the pixel coordinates. Then, a signal segment before and after the echo position is captured to form a short-time echo signal. A Fourier transform is then performed on the short-time echo signal to obtain its spectrum. Next, the spectral intensity value corresponding to the probe's center frequency is selected and multiplied with the pixel echo signal intensity value to obtain a high-quality imaging result. This invention can suppress strong noise without losing other information.

Description

Technical Field

[0001] This invention applies to the field of ultrasound imaging, specifically a probe center frequency intensity coefficient weighted ultrasound imaging method. Background Technology

[0002] Ultrasonic imaging equipment is widely used. Existing ultrasonic imaging equipment can be divided into two types based on the probe: one uses a multi-element array probe for imaging, and the other uses a single-element probe. Array probe imaging constructs an imaging vector based on the echo signals received by each element according to the pixel position, and then uses a time-delay superposition technique for imaging. Adaptive weighting methods can improve image quality; however, existing adaptive weighting coefficients are calculated based on the array probe's imaging vector and are not suitable for single-element probe-based imaging methods. Compared to array probe-based methods, single-element probe-based imaging methods have advantages such as lower complexity, simpler system structure, lower cost, and easier implementation; however, they suffer from significant differences in image quality, such as lower contrast and poorer signal-to-noise ratio. Therefore, improving the imaging quality of single-element imaging equipment is urgently needed. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention proposes an ultrasound imaging method based on probe center frequency intensity coefficient weighting. This method is applicable to imaging systems based on single-element ultrasound probes and can effectively suppress noise to improve imaging contrast, thereby improving the imaging quality of single-element ultrasound imaging systems.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0005] The present invention provides a probe center frequency intensity coefficient weighted ultrasound imaging method, characterized by comprising the following steps:

[0006] Step 1: The ultrasonic equipment uses a high-voltage pulse wave to excite the single-element ultrasonic probe, and after emitting ultrasonic waves into the imaging area, it collects the echo signal from the imaging area.

[0007] Step 2: Based on the coordinate information of the pixels in the imaging area and the position information of the probe, determine the position p and signal intensity s(p) of any pixel in the imaging area located on the center line of the ultrasonic beam emitted by the probe in the echo signal;

[0008] Step 3: Set the length of the short-time signal, and according to the length, obtain a segment of the signal containing position p from the echo signal and use it as the short-time echo signal. Perform a Fourier transform on the short-time echo signal to obtain the spectrum S(p,f) of the short-time signal; where f represents the frequency.

[0009] Step 4: Set the bandwidth parameter, and based on the center frequency f of the ultrasonic probe. m The calculation range f of the spectrum is set. n Thus, within the calculation range f n The center frequency intensity coefficient of the probe is calculated using the bandwidth parameter.

[0010] Step 5: Multiply the center frequency intensity coefficient of the probe by the signal intensity s(p) to obtain the imaging result of the pixel; thus obtaining the imaging result of all pixels on the center line;

[0011] Step Six: Change the position of the probe and repeat steps one to five to obtain the imaging results of all pixels on the center line of the ultrasonic beam emitted by the probe under different probe positions. Use these results as the imaging results of the imaging area. Then, normalize the imaging results of the imaging area and perform grayscale processing to obtain a high-quality ultrasonic image.

[0012] The characteristic of the probe center frequency intensity coefficient weighted ultrasound imaging method of the present invention is that the probe center frequency intensity coefficient MF in step four... T It is obtained using equation (1):

[0013]

[0014] In equation (1), α is the intensity adjustment coefficient.

[0015] In step three, the length of the short-time signal is not less than the wavelength λ of the ultrasonic signal emitted by the probe, and λ is obtained from equation (2):

[0016]

[0017] In equation (2), c is the sound velocity in the imaging region.

[0018] The intensity adjustment coefficient α ranges from 0.1 to 10.

[0019] The calculation range of the spectrum f n Not greater than the center frequency f of the ultrasonic probe m .

[0020] The present invention provides an electronic device, including a memory and a processor, wherein the memory is used to store a program that supports the processor in executing the ultrasound imaging method, and the processor is configured to execute the program stored in the memory.

[0021] The present invention discloses a computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, performs the steps of the ultrasound imaging method.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] In this invention, the probe center frequency intensity coefficient can effectively distinguish between effective signals and noise in the echo signal within the imaging area. By weighting the probe center frequency intensity coefficient with the echo signal intensity value corresponding to the pixel, the imaging quality of the single-element imaging device is improved, the contrast is enhanced, and the impact of noise on the imaging results is reduced. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of single-element probe imaging.

[0025] Figure 2 This is a flowchart of the method of the present invention;

[0026] Figure 3 This is a diagram showing the direct imaging results of a single-element probe simulating scattering points in this invention.

[0027] Figure 4 This is a weighted imaging result of the probe center frequency intensity coefficient of the simulated scattering point in this invention. Detailed Implementation

[0028] In this embodiment, as Figure 1 As shown, the single-element ultrasonic imaging device uses a single-element probe to emit ultrasonic signals to the imaging area and images all the pixels along the center line of the sound beam emitted by the probe at that position. Then, the probe is moved to the next position and images all the pixels along the center line of the sound beam emitted by the probe at that position are formed. The scanning of all pixels in the imaging area is completed by moving the probe.

[0029] In this embodiment, as Figure 2 As shown, an ultrasound imaging method weighted by the center frequency intensity coefficient of the probe includes:

[0030] Step 1: The ultrasonic equipment uses a high-voltage pulse wave to excite the single-element ultrasonic probe, and after emitting ultrasonic waves into the imaging area, it collects the echo signal from the imaging area.

[0031] Step 2: Based on the coordinate information of the pixels in the imaging area and the position information of the probe, determine the position p and signal intensity s(p) of any pixel in the imaging area located on the center line of the ultrasonic beam emitted by the probe in the echo signal;

[0032] Step 3: Set the length N of the short-time signal, and according to the length, obtain a segment of the signal containing position p from the echo signal and use it as the short-time echo signal. Perform Fourier transform on the short-time echo signal, and then use Equation (1) to obtain the spectrum S(p,f) of the short-time signal; where f represents the frequency.

[0033]

[0034] In equation (1), n ​​represents the coordinate position of the window function, w(np) represents the window function value at coordinate position np, s(n) represents the signal strength at coordinate position n, and j represents the imaginary number.

[0035] Step 4: Set the bandwidth parameter f b Based on the center frequency f0 of the probe, the center frequency intensity coefficient MF at position p is calculated using equation (2). T (p):

[0036]

[0037] In equation (1), α is the intensity adjustment coefficient. S(p,f0) represents the spectrum of the center frequency f0 at position p;

[0038] For noisy echo signals, the main energy of the echo signal is concentrated near the center frequency of the probe in the corresponding spectrum, while the energy of the noise is relatively small. Therefore, MF T This exhibits a larger value, while for noise signals, the spectrum is wider, with lower spectral intensity near the probe's center frequency, therefore MF... T It exhibits a relatively small value. The intensity adjustment factor is used to adjust MF. T The range of variation is adjusted to ensure applicability to signals with different signal-to-noise ratios.

[0039] Step 5: Multiply the center frequency intensity coefficient of the probe by the signal intensity s(p) to obtain the imaging result of the pixel; thus, the imaging result of all pixels on the center line is obtained.

[0040] Step Six: Change the position of the probe, such as... Figure 1 As shown, repeat steps one to five to obtain the imaging results of all pixels on the center line of the ultrasonic beam emitted by the probe at different probe positions, and use them as the imaging results of the imaging area. Then, normalize the imaging results of the imaging area and perform grayscale processing to obtain a high-quality ultrasonic image.

[0041] In this embodiment, an electronic device includes a memory and a processor. The memory stores a program that supports the processor in executing the above-described method, and the processor is configured to execute the program stored in the memory.

[0042] In this embodiment, a computer-readable storage medium stores a computer program, which is executed by a processor to perform the steps of the above method.

[0043] Example:

[0044] In this embodiment, a simulated ultrasound imaging system is first established, using a single-element point-focusing circular probe. The probe array diameter is 10mm, and the center frequency is 5MHz. The transmitted signal is a pulse wave, and the system sampling frequency is 40MHz. The sound velocity in the imaging area is 1540m / s, and the focal depth is 20mm. To verify the effectiveness of the algorithm, Gaussian white noise of a certain intensity is added to the simulated echo signal. The imaging target consists of three strong echo scattering points spaced 1mm apart, with pixel coordinates of (-1mm, 20.3mm), (0mm, 20.3mm), and (1mm, 20.3mm), respectively. The imaging results are as follows: Figure 3 As shown.

[0045] Figure 3 The results are from direct imaging, and obvious noise is visible in the background. Figure 4 The image is the result after weighting by the frequency intensity coefficient at the transmission center. In this embodiment, the adjustment coefficient α is 1, and the calculation frequency range is set to [4.843MHz, 5.156MHz], i.e., f n The frequency is 0.165MHz. It is evident that the background noise is significantly reduced, and the clarity of the three points is also significantly improved.

Claims

1. A method for ultrasound imaging using probe center frequency intensity coefficient weighting, characterized in that, Includes the following steps: Step 1: The ultrasonic equipment uses a high-voltage pulse wave to excite the single-element ultrasonic probe, and after emitting ultrasonic waves into the imaging area, it collects the echo signal from the imaging area. Step 2: Based on the coordinate information of the pixels in the imaging area and the position information of the probe, determine the position p and signal intensity s(p) of any pixel in the imaging area located on the center line of the ultrasonic beam emitted by the probe in the echo signal; Step 3: Set the length of the short-time signal, and according to the length, obtain a segment of the signal containing position p from the echo signal and use it as the short-time echo signal. Perform a Fourier transform on the short-time echo signal to obtain the spectrum S(p,f) of the short-time signal; where f represents the frequency. Step 4: Set the bandwidth parameter, and based on the center frequency f of the ultrasonic probe. m The calculation range f of the spectrum is set. n Thus, within the calculation range f n The center frequency intensity coefficient of the probe is calculated using the bandwidth parameter. Step 5: Multiply the center frequency intensity coefficient of the probe by the signal intensity s(p) to obtain the imaging result of the pixel; thus obtaining the imaging result of all pixels on the center line; Step Six: Change the position of the probe and repeat steps one to five to obtain the imaging results of all pixels on the center line of the ultrasonic beam emitted by the probe under different probe positions. Use these results as the imaging results of the imaging area. Then, normalize the imaging results of the imaging area and perform grayscale processing to obtain a high-quality ultrasonic image.

2. The ultrasound imaging method weighted by probe center frequency intensity coefficient as described in claim 1, characterized in that, Step 4: Probe center frequency intensity coefficient MF T It is obtained using equation (1): In equation (1), α is the intensity adjustment coefficient.

3. The probe center frequency intensity coefficient weighted ultrasound imaging method as described in claim 1, characterized in that, In step three, the length of the short-time signal is not less than the wavelength λ of the ultrasonic signal emitted by the probe, and λ is obtained from equation (2): In equation (2), c is the sound velocity in the imaging region.

4. The ultrasound imaging method weighted by probe center frequency intensity coefficient as described in claim 2, characterized in that, The intensity adjustment coefficient α ranges from 0.1 to 10.

5. The ultrasound imaging method weighted by probe center frequency intensity coefficient as described in claim 2, characterized in that, The calculation range of the spectrum f n Not greater than the center frequency f of the ultrasonic probe m .

6. An electronic device, comprising a memory and a processor, characterized in that, The memory is used to store programs that support the processor in executing any of the ultrasound imaging methods of claims 1-5, and the processor is configured to execute the programs stored in the memory.

7. A computer-readable storage medium storing a computer program thereon, characterized in that, The computer program, when run by a processor, performs the steps of the ultrasound imaging method according to any one of claims 1-5.

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