An Adaptive Sound Velocity Calculation Method and Device for a Medical Ultrasonic Device

Abstract

The present invention provides a method and device for adaptively calculating the sound speed of a medical ultrasound device. The method includes: obtaining a first delay address according to a reference sound speed; setting a neighborhood address range for each channel respectively with the first delay address value as the center; performing cross-correlation operations on the middle two channels respectively within the neighborhood address range and determining the operation direction; performing cross-correlation calculations on all channels according to the operation direction to determine a second delay address; performing quadratic parabola fitting on the second delay address values of each channel as samples to determine a fitting curve and obtaining a first fitting coefficient; obtaining an optimal sound speed based on the first fitting coefficient; re-correcting the first delay address by the optimal sound speed to obtain a third delay address; and completing beam synthesis at the current point by the third delay address. The present invention can meet the requirements of various medical ultrasound device systems, avoid the traditional manually intervened sound speed setting method, and can quickly obtain high-precision sound speed calculation results.

Description

Technical Field

[0001] The present invention relates to the technical field of medical ultrasound devices, and particularly to a method and device for adaptively calculating the sound speed of a medical ultrasound device. Background Art

[0002] Currently, in a digital ultrasound system, the most important part is beamforming, and the final digitization of beamforming needs to be quantified by the sound speed. For dynamic receive beamforming, focusing (beamforming) needs to be performed at each detection distance, the delay value is calculated, and the sound speed is used for quantization digitization. However, due to the nonlinearity of human tissues, the speed of ultrasonic waves changes when propagating in human tissues. In traditional digital ultrasound, it is generally assumed that the sound speed in human tissues is a fixed value, and a series of sound speed values are artificially set to perform digitization processing on the delay value of beamforming, resulting in a relatively low focusing accuracy of the final beamforming and affecting the resolution of the image. This makes it necessary in the ultrasound industry to have a method for adaptively calculating the sound speed. Now, many ultrasound device companies have proposed their own sound speed calculation algorithms. However, these methods are either still relatively simple and have low implementation accuracy. Therefore, there is an urgent need for a simple, easy-to-implement, fast, and high-precision sound speed calculation algorithm. Summary of the Invention

[0003] One of the purposes of the present invention is to provide a method for adaptively calculating the sound speed of a medical ultrasound device, which can meet the requirements of various medical ultrasound device systems, avoids the traditional manual intervention-based sound speed setting method, and can quickly obtain a high-precision sound speed calculation result.

[0004] A method for adaptively calculating the sound speed of a medical ultrasound device provided by an embodiment of the present invention includes:

[0005] Obtain a first delay address according to a reference sound speed;

[0006] Set a neighborhood address range for each channel with the first delay address value as the center;

[0007] Perform cross-correlation operations on the middle two channels respectively within the neighborhood address range and determine the operation direction;

[0008] Perform cross-correlation calculations on all channels according to the operation direction to determine a second delay address;

[0009] Use the second delay address values of each channel as samples to perform quadratic parabola fitting to determine a fitting curve and obtain a first fitting coefficient;

[0010] Obtain an optimal sound speed based on the first fitting coefficient;

[0011] Recalibrate the first delay address with the optimal sound speed to obtain a third delay address;

[0012] The beam synthesis of the current point is completed by the third delay address.

[0013] Preferably, a reference sound speed is preset and quantified to obtain a first delay address value. The preset value is the known speed of ultrasonic waves propagating in various tissues, which can be a single value or a series of adjustable known values. The first delay address value is obtained by dividing the distance traveled by the ultrasonic wave by the minimum distance interval.

[0014] Preferably, the neighborhood address range is a one-dimensional region covering both positive and negative directions. Greater than the first address value is the positive direction, and less than the first address is the negative direction.

[0015] Preferably, one, two, or more than two channels can be selected in the middle channel for calculation to determine the calculation direction of the sound speed at the current point.

[0016] Preferably, the calculation method of the second delay address value is consistent with the algorithm for determining the direction in claim 4.

[0017] Preferably, the fitting function is a parabola function, and the first fitting coefficient is the coefficient of the quadratic term of the parabola function.

[0018] Preferably, the mathematical relationship between the optimal sound speed and the reference sound speed is used to correct the first delay address to obtain the third delay address, which is used to index the original data of each channel for beam synthesis.

[0019] An adaptive sound speed calculation device for a medical ultrasonic device provided by an embodiment of the present invention includes:

[0020] A first delay address calculation device for calculating the first delay address value;

[0021] A second delay address calculation device for calculating the second delay address value from the first delay address

[0022] A delay address fitting device for each channel, which is a device for performing mathematical function fitting calculation on the second delay address value;

[0023] An address correction device for each channel, which is a device for correcting the first address by the optimal sound speed;

[0024] A third delay address calculation device for calculating the third delay address value;

[0025] A raw data storage device for storing the original radio frequency or baseband digital signals of each channel of the color Doppler ultrasound device;

[0026] A beam synthesis device, which is a device for obtaining the corresponding raw data from the storage device by the third address and performing weighted summation.

[0027] Other features and advantages of the present invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention may be realized and attained by the structure particularly pointed out in the written description, claims, as well as the drawings.

[0028] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0029] The drawings are used to provide a further understanding of the present invention, and constitute a part of the description. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0030] Figure 1 It is a flowchart of a method for calculating the adaptive sound speed of a medical ultrasound device in an embodiment of the present invention;

[0031] Figure 2 It is a schematic diagram of the arrangement of address-channel spatial echo data in an embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of a device for calculating the adaptive sound speed of a medical ultrasound device in an embodiment of the present invention. Detailed Embodiments

[0033] The preferred embodiments of the present invention will be described below with reference to the drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0034] The embodiment of the present invention provides a method for calculating the adaptive sound speed of a medical ultrasound device, including:

[0035] Obtaining a first delay address according to a reference sound speed;

[0036] Setting a neighborhood address range for each channel with the first delay address value as the center;

[0037] Performing a cross-correlation operation on the middle two channels within the neighborhood address range and determining the operation direction;

[0038] Performing a cross-correlation calculation on all channels according to the operation direction to determine a second delay address;

[0039] Performing a quadratic parabola fitting on the second delay address values of each channel to determine a fitting curve and obtaining a first fitting coefficient;

[0040] Obtaining an optimal sound speed based on the first fitting coefficient;

[0041] Recalibrating the first delay address with the optimal sound speed to obtain a third delay address;

[0042] The beamforming of the current point is completed by the third delay address.

[0043] A reference sound speed is preset and quantized to obtain a first delay address value. The preset value is the known speed of ultrasonic wave propagation in each tissue, which can be a single value or a series of adjustable known values. The first delay address value is obtained by dividing the distance traveled by the ultrasonic wave by the minimum distance interval.

[0044] The neighborhood address range is a one-dimensional region covering both positive and negative directions. Values greater than the first address value are in the positive direction, and values less than the first address are in the negative direction.

[0045] One, two or more than two channels can be selected in the intermediate channel for calculation to determine the calculation direction of the sound speed at the current point.

[0046] The calculation method of the second delay address value is consistent with the algorithm for determining the direction in claim 4.

[0047] The fitting function is a parabola function, and the first fitting coefficient is the coefficient of the quadratic term of the parabola function.

[0048] The mathematical relationship between the optimal sound speed and the reference sound speed is used to correct the first delay address to obtain the third delay address, which is used to index the original data of each channel for beamforming.

[0049] The working principle and beneficial effects of the above technical solutions are as follows:

[0050] Beamforming: Combining multiple ultrasonic signals into one signal is beamforming;

[0051] Delay parameter: When multiple ultrasonic waves reach the target point, there is a sequence of arrival. This time difference is the delay parameter;

[0052] Dynamic reception: In a medical color Doppler ultrasound device, the direction of ultrasonic wave transmission is artificially defined as the axial direction. Ultrasonic waves are received in segments at regular intervals along the axial direction. This reception method is called dynamic reception;

[0053] Focusing: Multiple ultrasonic signals just arrive at the same time at a certain depth in the axial direction, which is called focusing;

[0054] Beam: The ultrasonic signal after beamforming is called a beam, and can also be called a beam line, or a line, etc.;

[0055] RF data: The data after the final beamforming.

[0056] In a digital ultrasound system, the most important part is beam synthesis, and the final digitization of beam synthesis requires quantization calculation by the speed of sound. This patent proposes a high-precision, point-by-point speed-of-sound calculation algorithm that can meet the requirements of various medical ultrasound device systems. This patent avoids the traditional manually intervened speed-of-sound setting method and can quickly obtain high-precision speed-of-sound calculation results.

[0057] An implementable technical solution of the present invention: The steps of an adaptive speed-of-sound implementation case of a medical ultrasound device are as follows:

[0058] As Figure 1 in S10, the first delay address is obtained according to the reference speed of sound Vsound1 and set as Address1(i,j). The first delay address is a parabola function opening downward. As Figure 2 in S22, the specific delay address calculation formula can be calculated as follows:

[0059]

[0060] Where: (ElementX, ElementY) are the array element coordinates of the probe; (X, Y) are the coordinates of the point where beam synthesis is currently required; Ts is the minimum sampling time; F is the depth of the current sampling point; i is the channel number, and j is the longitudinal depth point number.

[0061] As Figure 1 in S11, a neighborhood address range Ω(i,j) is set for each channel with the first delay address value as the center. The mathematical expression can be represented as:

[0062] Ω(i,j) ∈ [Address1(i,j) - L / 2, Address1(i,j) + L / 2]

[0063] Where: L is the length of the neighborhood along the j direction, and [] represents the symbol of the upper and lower limits of the domain;

[0064] The neighborhood address range Ω(i,j) is a one-dimensional region covering both positive and negative directions. Greater than the first address value is the positive direction and is positive, indicating that the speed is greater than the reference speed; less than the first address is the negative direction and is negative, indicating that the speed is less than the reference speed;

[0065] As Figure 1 in S12, within the Ω(i,j) neighborhood range of the first address Address1(i,j), cross-correlation operations are respectively performed on the middle two channels and the operation direction is determined. The middle channel numbers can select two channels of ChN / 2 and ChN / 2 - 1 to continue the cross-correlation operations respectively. The cross-correlation calculation formula can be expressed as follows:

[0066]

[0067] Respectively confirm the maximum values of the calculated C(ChN / 2,j) and C(ChN / 2 - 1,j) in the domain Ω(i,j), and record the tag values of the maximum values MaxIndex(ChN / 2 - 1,k) and MaxIndex(ChN / 2,k). The calculation directions can be expressed as follows:

[0068]

[0069] Where: AD(i,j) is the pre - stored discrete echo signal; ChN is the total number of receiving channels of the current system;

[0070] Such as Figure 1 in S13, all channels are in the determined direction. Such as Figure 2 in S21 or S22, calculate the second delay address within the range of Ω1(i,j). The second delay address value determines the maximum value tag MaxIndex(i,k) according to the cross - correlation formula in step 3. The second delay address calculation formula is as follows:

[0071] Address2(i,j) = [Address1(i,j)+MaxIndex(i,k)] ∈ Ω1

[0072] Such as Figure 1 in S14, taking the second address value Address2(i,j) of each channel as a sample for fitting, the first fitting coefficient for calculating the sound speed can be obtained. The fitting function is a parabola function, and the fitting method can adopt the conventional least - squares method. The first fitting coefficient is the coefficient A1 of the quadratic term of the parabola function. The parabola function can be set as:

[0073] Address(i,j) = A1*I 2 +A2*I + A3

[0074] Such as Figure 1 In S15, according to the relationship between the known first coefficient A1 and the sound speed, the optimal sound speed value can be calculated as follows:

[0075]

[0076] Such as Figure 1 in S16, obtaining the optimal sound speed Vopt of the current sampling point from the first coefficient A1. In an implementable case, the sound speed Vsound1 in the Address1(i,j) calculation formula in step 1 can be directly replaced, so as to obtain a new delay address value, denoted as Address3(i,j), which is used to index the original RF data or baseband signals of each channel in the storage area. The indexed channel data then enters the beamforming device for beamforming.

[0077] The probe emits, receives echo data of each channel and stores them; obtains the first delay address according to the reference sound speed, and sets the neighborhood address range for each channel with the first delay address value as the center; performs operations on the middle channel within this range to determine the operation direction, and determines the second delay address for all channels according to the operation direction; determines the fitting curve from the second delay address value and obtains the first fitting coefficient, and obtains the optimal sound speed from the first fitting coefficient; re-corrects the first delay address with the optimal sound speed to obtain the third delay address; completes the beamforming of the current point with the third delay address;

[0078] As described above, the first delay address is obtained by quantifying the preset reference sound speed;

[0079] As described above, the neighborhood address range can be provided by a preset value or set adaptively;

[0080] The operation direction is centered on the first delay address, with downward indicating the positive direction and upward indicating the negative direction;

[0081] The fitting curve determined by the second delay address value is a parabola function with a downward opening, and the first fitting coefficient is the coefficient of the quadratic term of the parabola, and this coefficient is inversely proportional to the square of the sound speed;

[0082] As described above, the first delay address is re-corrected with the optimal sound speed, and the third delay address is obtained by increasing or decreasing the address according to the optimal sound speed, the reference sound speed, and the operation direction.

[0083] The present application has achieved the following beneficial effects:

[0084] 1. Fast. By calculating the sound speed transmission situation of the central channel, the increasing or decreasing direction of the sound speed can be quickly obtained, changing from bidirectional calculation to unidirectional calculation;

[0085] 2. High precision. In theory, this algorithm can achieve the accuracy of the system sampling clock in terms of depth;

[0086] 3. Strong implementability. It can be simply and quickly deployed in various color Doppler ultrasound systems.

[0087] An adaptive sound speed calculation device for a medical ultrasound device provided by an embodiment of the present invention, as Figure 3 shown, includes:

[0088] The first delay address calculation device S30, which is used to calculate the first delay address value device;

[0089] The second delay address calculation device S31, which calculates the second delay address value device from the first delay address

[0090] The delay address fitting device S32 for each channel, which is a device for performing mathematical function fitting calculation on the second delay address value;

[0091] Each channel address correction device S33, which is a device for correcting the first address with the optimal sound speed;

[0092] The third delay address calculation device S34, which is a device for calculating the third delay address value;

[0093] The original data storage device S35, which is used to store the original radio frequency or baseband digital signals of each channel of the color ultrasound device;

[0094] The beam synthesis device S36, which is a device for obtaining the corresponding original data from the storage device according to the third address and performing weighted summation.

[0095] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. An adaptive sound velocity calculation method for a medical ultrasound device, characterized in that Including: Obtain the first delay address according to the reference sound speed; Set the neighborhood address range for each channel respectively with the first delay address value as the center; Perform cross-correlation operations on the middle two channels respectively within the neighborhood address range and determine the operation direction; Perform cross-correlation calculations on all channels according to the operation direction to determine the second delay address; Perform quadratic parabola fitting with the second delay address values of each channel as samples to determine the fitting curve and obtain the first fitting coefficient; Obtain the optimal sound speed based on the first fitting coefficient; Recalibrate the first delay address with the optimal sound speed to obtain the third delay address; Complete the beam synthesis of the current point with the third delay address.

2. The adaptive sound speed calculation method of a medical ultrasound device according to claim 1, characterized in that Preset the reference sound speed and quantize it to obtain the first delay address value. The preset value is the known speed of ultrasonic wave propagation in each tissue, which can be a single value or a series of adjustable known values. The first delay address value is obtained by dividing the distance traveled by the ultrasonic wave by the minimum distance interval.

3. The adaptive sound speed calculation method of a medical ultrasound device according to claim 1, characterized in that, The neighborhood address range is a one-dimensional region covering both positive and negative directions. Greater than the first address value is the positive direction, and less than the first address is the negative direction.

4. The adaptive sound speed calculation method of a medical ultrasound device according to claim 1, characterized in that, One, two or more than two channels can be selected for the middle channels to perform operations to determine the operation direction of the sound speed at the current point.

5. The adaptive sound speed calculation method for a medical ultrasound device according to claim 4, wherein The second delay address value is calculated based on the operation direction.

6. The adaptive sound speed calculation method for a medical ultrasound device according to claim 1, wherein The fitting function is a parabola function, and the first fitting coefficient is the coefficient of the quadratic term of the parabola function.

7. The adaptive sound speed calculation method of a medical ultrasound device according to claim 1, wherein The mathematical relationship between the optimal sound speed and the reference sound speed is used to recalibrate the first delay address to obtain the third delay address, which is used to index the original data of each channel for beam synthesis.

8. An adaptive sound velocity calculation device for a medical ultrasound device, characterized in that, Including: The first delay address calculation device is used to obtain the first delay address according to the reference sound speed; The second delay address calculation device is used to set the neighborhood address range for each channel respectively with the first delay address value as the center, perform cross-correlation operations on the middle two channels respectively within the neighborhood address range and determine the operation direction, and perform cross-correlation calculations on all channels according to the operation direction to determine the second delay address; The delay address fitting device for each channel is used to perform quadratic parabola fitting with the second delay address values of each channel as samples to determine the fitting curve and obtain the first fitting coefficient, and obtain the optimal sound speed based on the first fitting coefficient; The third delay address calculation device is used to recalibrate the first delay address with the optimal sound speed to obtain the third delay address; The beam synthesis device is used to complete the beam synthesis of the current point with the third delay address.

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