TWI597515B - Parameter setting method of ultrasonic transducer - Google Patents

Description

Ultrasonic probe parameter setting method

The present invention relates to an ultrasonic probe, and more particularly to a parameter setting method for an ultrasonic probe.

In ultrasonic acoustic images, a spatial compounding method or a frequency compounding method is often used for pre-scanning. The spatial composite method is achieved by capturing multiple images of the same target object from different angles, and the frequency composite method is achieved by capturing multiple images of the same target object in different frequency ranges.

However, in the spatial composite approach, the spatial resolution will be reduced by measuring the beam size increased by the target object from different angles. Similarly, in the frequency recombination method, the spatial resolution is reduced by the bandwidth generated by the pulse length becoming longer. Therefore, the composite image obtained by simply using the spatial composite method or the frequency composite method severely reduces the contrast analysis ability due to the appearance of speckle, and cannot change or adjust the frequency or angle used by the current ultrasonic probe. It is impossible to adjust to the best image quality.

The invention relates to a parameter setting method for an ultrasonic probe, which can first match an uncorrelated ultrasonic image with different frequency range or different angle ranges, and then perform pre-combination and aim for a spot in the composite image. The size is judged to find an optimum parameter setting value of the ultrasonic probe.

According to an aspect of the invention, a parameter setting method of an ultrasonic probe is provided, which comprises the following steps. A plurality of ultrasonic waves are emitted by an ultrasonic probe, and echo signals of each group of ultrasonic waves are received, wherein each group of ultrasonic waves has different transmission frequencies. Converting echo signals of multiple sets of ultrasonic waves into multiple digitalized ultrasonic images. For the digitalized ultrasonic images, the two images are pre-combined into a plurality of ultrasonic composite images, and the non-correlation matching values of the two images are greater than a predetermined value. In the supersonic composite image, an optimized image with the smallest spot size and the non-correlation value greater than the first set value is compared, and an emission frequency corresponding to the optimized image is used as an optimization of the ultrasonic probe. Parameter setting value.

In order to better understand the above and other aspects of the present invention, the preferred embodiments are described below, and in conjunction with the drawings, the detailed description is as follows:

M1, M2‧‧‧ ultrasound image

C1, C2‧‧‧ curve

AP‧‧‧ intersection

SE‧‧‧Optimized parameter setting

S10~S15‧‧‧Steps

FIG. 1 is a flow chart showing a method for setting parameters of an ultrasonic probe according to an embodiment of the invention.

Figure 2 is a graph showing the correlation coefficient and the corresponding depth.

Figure 3 is a diagram showing the judgment reference of the optimized image.

In an example of the embodiment, a parameter setting method of the ultrasonic probe is proposed. Ultrasonic probes such as linear array probes, phase arrays Head or other type of probe. The ultrasonic probe comprises a plurality of ultrasonic array elements, and each ultrasonic array element is a transducer for converting the pulse voltage signal outputted by the high-frequency pulse generator into a mechanically oscillated ultrasonic wave and transmitting it into the tissue. . Then, each of the ultrasonic array elements receives the echo signals reflected by the internal scattering elements and converts them into pulse voltage signals to obtain a set of scanning signals. When the incident wavelength of the ultrasonic wave is much larger than the diameter of the scatterer inside the tissue, ultrasonic scattering occurs, and the reverse scatter signal will appear randomly bright spots in the B-mode image. This is called speckle. . The presence of the flare blurs the fine-grained image, reducing the contrast and resolution of the ultrasound image.

In this embodiment, the optimal parameter setting can be performed on any type of ultrasonic probe, the correlation of the ultrasonic image is evaluated according to the echo signal of the ultrasonic wave, and the uncorrelated ultrasonic image is found, and then, according to the spatial composite (spatial) The compounding method or the frequency compounding method performs pre-combination, and then performs an alignment analysis based on the ultrasonic composite image to determine the spot size or the histogram of the ultrasonic composite image corresponding to the non-correlation greater than the first set value. The area of the map. In this way, the optimized image can be compared from the supersonic composite images, and the transmission frequency or the emission angle of the optimized image is used as an optimum parameter setting value of the ultrasonic probe.

The embodiments are described in detail below, and the embodiments are only intended to be illustrative and not intended to limit the scope of the invention.

Please refer to FIG. 1 , which is a flow chart of a method for setting parameters of an ultrasonic probe according to an embodiment of the invention. First, in step S10, a plurality of sets of ultrasonic waves are emitted by an ultrasonic probe, and echo signals of each group of ultrasonic waves are received, wherein each group of ultrasonic waves respectively have different transmission frequencies or have different emission angles. In a In an embodiment, when the scattering sub-location within the tissue is within a depth of 6 cm, the ultrasonic probe is pre-scanned with a plurality of sets of ultrasonic waves within 40% to 90% of the available scanning frequency band to find a suitable depth interval. The center frequency is within 6 cm. In another embodiment, when the depth range of the scatterers inside the tissue is more than 6 cm, the ultrasonic probe is pre-scanned with a plurality of sets of ultrasonic waves within 10% to 60% of the available scanning frequency band to find the above suitable The center frequency of the depth interval exceeding 6 cm. In another embodiment, the ultrasonic probe is pre-scanned, for example, with a plurality of sets of ultrasonic waves in the range of -20 degrees to 20 degrees of the zero-degree emission angle of the ultrasonic probe to find a suitable emission angle.

In general, the performance of the probe, such as the emission angle of the pulse signal and the center frequency, will set a fixed transmission frequency or a fixed emission angle when scanning, and cannot be changed for the frequency or angle used by the current ultrasonic probe. Or adjust. The invention provides an adaptive composite image ultrasonic wave, which can be changed or adjusted for the frequency or angle used by the ultrasonic probe, please refer to steps S11~S15.

In step S11, the echo signals of the plurality of sets of ultrasonic waves are converted into a plurality of digitalized ultrasonic images to facilitate the comparison analysis. Next, in step S12, a non-correlation between the two images in the digitized ultrasonic images is matched to evaluate whether the non-correlation matching value is greater than a predetermined value. That is to say, the non-correlation analysis is performed on the ultrasonic images generated by two different transmission frequencies or two different emission angles. When the non-correlation is larger, it means that the difference between the two images is larger, but in order to avoid taking two images with non-correlation maxima, it is necessary to further consider the spot size to determine the optimal parameter setting value.

In step S12, the non-correlation matching step is, for example, from such digits In the ultrasound image, a digital ultrasound image is selected as a reference image for matching the reference, or the digital ultrasound images are compared with each other. In an embodiment, when the center frequency of the ultrasonic probe is used as a matching reference, the reference image used as the matching reference may be a digitalized ultrasonic image generated corresponding to the center frequency of the ultrasonic probe.

In another embodiment, when the zero-degree emission angle of the ultrasonic probe is used as a matching reference, the reference image used as the matching reference may be a digitalized ultrasonic image generated corresponding to the zero-degree emission angle of the ultrasonic probe.

Please refer to FIG. 2, which is a graph showing the correlation coefficient and the corresponding depth. In Fig. 2, the two ultrasonic images M1 and M2 are less than 4 cm in the depth interval, and the correlation coefficient is greater than 0.8, indicating that the difference between the two ultrasonic images M1 and M2 is within a predetermined value; When the correlation coefficient is less than 0.5, it means that the difference between the two ultrasonic images M1 and M2 has exceeded the predetermined value. Therefore, in FIG. 2, when the first set value is 0.5, the depth interval boundary may be selected as 6-10 cm as the depth interval corresponding to the non-correlation greater than the first set value.

Next, in step S13, the two images in the digitalized ultrasonic images are pre-combined into a plurality of ultrasonic composite images, and the non-correlation matching values of the two images are greater than a predetermined value (for example, greater than 0.5 or less). And these supersonic composite images were compared for analysis. That is to say, two or two different emission frequencies or two different two different emission angles are pre-compounded to form a plurality of ultrasonic composite images, and the ultrasonic composite images are compared to determine The size of the spot size of each ultrasonic composite image.

In an embodiment, the transmission frequency of the ultrasonic image is, for example, 6.5MHz, 7.5MHz and 8.5MHz, the ultrasonic images generated by the three different transmission frequencies are matched two by two to form three sets of ultrasonic images and pre-synthesized into three sets of ultrasonic composite images, and then these super The sound wave composite images are compared to determine the spot size of each ultrasonic composite image.

In one embodiment, the alignment analysis step calculates the spot size by, for example, the Sum of absolute differences (SAD) of the pixel grayscale differences of the respective ultrasonic composite images. When the absolute value of the pixel gradation difference is larger, it means that the spot size is larger, and conversely, the smaller. The above-described spot size is represented, for example, by a histogram. When the area of the histogram is larger, the numerical value indicating the square sum of the pixel gradation differences is larger, and conversely, the smaller is smaller.

In one embodiment, the alignment analysis step calculates the spot size by, for example, the Sum of squared differences (SSD) of the pixel grayscale differences of the respective ultrasonic composite images. The larger the value of the sum of the squares of the pixel gradation differences, the larger the spot size, and vice versa. The above-described spot size is represented, for example, by a histogram. When the area of the histogram is larger, the numerical value indicating the square sum of the pixel gradation differences is larger, and conversely, the smaller is smaller.

Next, in step S14, an optimized image in which the spot size is the smallest and the non-correlation value is greater than the first set value is compared in the supersonic composite images. In step S15, a transmission frequency corresponding to the optimized image is used as an optimum parameter setting value of the ultrasonic probe.

Please refer to FIG. 3, which shows a judgment reference diagram of the optimized image. According to the above two determination methods, two curves C1 and C2 can be determined, that is, the first curve C1 generated by determining the non-correlation in step S11 and the second curve C2 generated by determining the spot size in step S13, wherein the two curves are C1, C2 intersection AP It is used to determine a transmission frequency or a transmission angle corresponding to the optimized image as an optimum parameter setting value SE of the ultrasonic probe.

The parameter setting method of the ultrasonic probe disclosed in the above embodiments of the present invention matches the non-correlation between two images in the digitalized ultrasonic image. The digitalized ultrasonic images are pre-synthesized into a plurality of ultrasonic composite images, and the ultrasonic composite images are compared and analyzed to determine the spot size of the ultrasonic image whose non-correlation value is greater than the first set value. . In the supersonic composite image, an optimized image with the smallest spot size and the non-correlation value greater than the first set value is compared, and an emission frequency corresponding to the optimized image is used as an optimization of the ultrasonic probe. Parameter setting value. Therefore, the present invention has an adaptive composite image ultrasonic adjustment function, which can be changed or adjusted for the frequency or angle currently used by the ultrasonic probe, so that each scan can be corrected to an optimal state to improve the ultrasonic wave. The quality of the image.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

S10~S15‧‧‧Steps

Claims (10)

A parameter setting method for an ultrasonic probe includes: transmitting a plurality of sets of ultrasonic waves by an ultrasonic probe, and receiving echo signals of each group of ultrasonic waves, wherein each group of ultrasonic waves respectively have different transmitting frequencies; the plurality of sets of ultrasonic waves The echo signal is converted into a plurality of digitized ultrasonic images; for the digitalized ultrasonic images, the two images are pre-combined into a plurality of ultrasonic composite images, and the non-correlation matching values of the two images are greater than a predetermined value. And aligning an optimized image with the smallest spot size and the non-correlation value greater than the first set value in the ultrasonic composite images, and using the one corresponding transmitting frequency of the optimized image as the ultrasonic probe One of the optimal parameter settings. The parameter setting method according to claim 1, wherein in the non-correlation matching step, a digitalized ultrasonic image is selected from the digitalized ultrasonic images as a reference image of a matching reference, or The digitalized ultrasound images are compared with each other. The parameter setting method according to claim 2, wherein the reference image used as a matching reference is a digitalized ultrasonic image corresponding to a center frequency of the ultrasonic probe. The parameter setting method according to claim 1, wherein in the comparison analysis step, the spot is calculated by the sum of absolute differences (Sum of absolute differences, SAD) of the ultrasonic composite images. Size. The parameter setting method according to claim 1, wherein in the comparison analyzing step, the spot size is calculated by Sum of squared differences (SSD) of the pixel gradation differences of the ultrasonic composite images. size. The parameter setting method according to claim 1, wherein when a scattering sub-interval within a tissue is within a depth interval and the depth interval is within 6 cm, the ultrasonic probe is 40% of the available scanning frequency band. The plurality of sets of ultrasonic waves within 90% are pre-scanned. The parameter setting method according to claim 1, wherein when a scattering sub-interval within a tissue is in a depth interval and the depth interval exceeds 6 cm, the ultrasonic probe is 10% of the available scanning frequency band. The plurality of sets of ultrasonic waves within 60% are pre-scanned. A parameter setting method for an ultrasonic probe includes: transmitting a plurality of sets of ultrasonic waves by an ultrasonic probe, and receiving echo signals of each group of ultrasonic waves, wherein each group of ultrasonic waves respectively have different emission angles; the plurality of sets of ultrasonic waves The echo signal is converted into a plurality of digitized ultrasonic images; for the digitalized ultrasonic images, the two images are pre-combined into a plurality of ultrasonic composite images, and the non-correlation matching values of the two images are greater than a predetermined value. And aligning an optimized image with the smallest spot size and the non-correlation value greater than the first set value in the supersonic composite images, and using the one of the emission angles corresponding to the optimized image as the ultrasonic probe One of the optimal parameter settings. The parameter setting method of claim 8, wherein in the non-correlation matching step, a digitalized ultrasonic image is selected from the digitalized ultrasonic images as a reference image of a matching reference, or The digitalized ultrasound images are compared with each other. The parameter setting method according to claim 9 , wherein the reference image as a matching reference is a number corresponding to a zero-degree emission angle of the ultrasonic probe Positioning the ultrasound image.