CN104323803B - Vocal cord vibration imaging based on plane wave ultra sonic imaging and measurement system and method - Google Patents

Abstract

The present invention relates to a vocal cord vibration imaging and measurement system and method based on plane wave ultrasonic imaging, including a digital ultrasonic imaging system, a data acquisition card and a computer; the digital ultrasonic imaging system includes an ultrasonic linear array transducer and a host computer; an ultrasonic linear array The transducer is used to send out ultrasonic plane waves under the control of the host, receive the echo, and send the echo back to the host; the host is used to control the ultrasonic linear array transducer to emit ultrasonic plane waves, and output the echo to the data acquisition card; The data acquisition card is used to convert the received echo signal into a digital signal and transmit it to the computer; the computer is used to convert the echo data of the received digital signal into beamforming, RF signal envelope detection and dynamic range compression into throat Image of departmental organization structure. The invention realizes the high-speed imaging of the vibrating vocal cords under the conditions of time synchronization and space synchronization, and quantifies and extracts the tissue mechanics parameters of the vibration and the phase change information of a specific position.

Description

Vocal fold vibration imaging and measurement system and method based on plane wave ultrasonic imaging

【Technical field】

The invention belongs to the field of biomedical information detection, and specifically relates to a system and method capable of performing time- and space-synchronized high-speed vibration imaging on vocal cords, and quantifying and extracting vocal cord time and space vibration characteristics.

【Background technique】

The high-speed, complex and multi-dimensional vibration of the vocal cords of the human body produces the voice source. It is the fastest vibrating small organ in the human body, and it is also the vocal organ most prone to damage. However, at present, the research on how the vocal cords change the vocalization mode by adjusting their own tissue mechanical properties, and how the lesion and injury cause changes in the tissue mechanical properties of the vocal cords, leading to pathological speech production is still in its infancy.

According to the anatomical structure of the vocal cord and its layered vibration model, the vocal cord is divided into two layers: the body layer and the covering layer. The vibration of the vocal cord is actually the combined effect of the vibration of the two layers of tissue with different tissue mechanical properties. Most of the current research on vocal fold vibrations has focused on the covering layer, because the covering layer vibration can be easily observed and recorded by laryngoscope. However, optical imaging techniques for the larynx and vocal cords, including stroboscopic dynamic laryngoscopy and high-speed video laryngoscopy, cannot image the vibration of the internal tissue structure below the surface of the vocal cords. In addition, the invasive nature of the optical device using the endoscope made it impossible for the subjects to vocalize in natural speech.

Electroglottography (EGG), as a research method that can reflect the periodic change of vocal cord contact area during vocalization, is widely used in clinical examination and scientific research of vocal cords. The feature points extracted from the EGG and the differential electroglottogram (DEGG) correspond to the physiological action points with special significance in the vocal cord vibration. In addition, the high temporal resolution of EGG and the easy extraction of recordings allow it to identify phase changes in vocal fold motion. However, the EGG signal is a one-dimensional comprehensive signal, which describes the overall situation of the entire vocal cord contact area. This is due to the fact that the EGG signal is a cumulative measurement of the contact of the vocal cords at all points along the glottis. determined. EGG therefore cannot reveal quantitative vibrational properties of specific tissue regions of the vocal cords.

Compared with the various technologies mentioned above, the advantage of medical ultrasound imaging technology is that it is non-invasive and can image the tissue structure below the surface of the vocal cords under the condition of the subject's natural vocalization. However, conventional ultrasound imaging technology adopts a line-by-line scan mode. In this scan mode, an image is divided into many scan lines, and the data on each scan line is in different This leads to a certain time difference in the acquisition of points at different positions in the image. Compared with the high-speed vibration of the vocal cords, this time difference cannot be ignored. In this case, the image becomes blurred by the high-speed vibration of the vocal cords, making it impossible to accurately measure the vibration speed and displacement of the vocal cords. In addition, because the imaging frame rate of this conventional ultrasound imaging method is low (<1000 Hz), it cannot meet the requirements for vocal fold vibration imaging in the case of non-steady-state vocalization.

Ultrasound glottograph (UGG) is another method that enables non-invasive observation of vocal cord dynamics. However, all the current reports on UGG use single-array ultrasonic transducers. The emitted beam of a single-array ultrasonic transducer has strong directivity, and it is impossible to determine the overall structure and position of the vocal cords. In the absence of image guidance, the detection of vocal fold vibration by a single array element transducer can easily lead to loss of information. The linear array transducer that can image the vocal cord vibration within the entire length of the vocal cords also has certain application limitations. In addition to the low frame rate of the line scan imaging, another main reason is the limited line scan in the ultrasonic line scan mode. Due to the scanning speed, the tissue structures at different positions in the same frame of B-ultrasound images are not collected at the same time. Since UGG reflects the phase information of vocal fold vibration, the asynchronous problem of this imaging is unacceptable.

Therefore, how to perform high-speed imaging of the vibrating vocal folds under the condition of time synchronization and space synchronization, and quantitatively extract the tissue mechanics parameters of vibration and phase change information at specific positions is still a big problem in this field.

【Content of invention】

The object of the present invention is to provide a vocal cord vibration imaging and measurement system and method based on plane wave ultrasonic imaging, to overcome the problems and limitations of the above-mentioned prior art in the research of vocal cord vibration; the present invention uses plane wave ultrasonic imaging technology (plane wave ultrasonography, PWU), to image and quantify vocal fold vibration properties.

In order to achieve the above object, the present invention adopts the following technical solutions:

A vocal cord vibration imaging and measurement system based on plane wave ultrasonic imaging, including a digital ultrasonic imaging system, a data acquisition card and a computer; the digital ultrasonic imaging system includes an ultrasonic linear array transducer and a host; the ultrasonic linear array transducer is used for Under the control of the host, the ultrasonic plane wave is sent out, and the echo is received, and the echo is sent back to the host; the host is used to control the ultrasonic linear array transducer to emit the ultrasonic plane wave, and output the echo to the data acquisition card; the data acquisition card is used for The received echo signal is converted into a digital signal and sent to the computer; the computer is used to perform beamforming, radio frequency signal envelope detection and dynamic range compression on the echo data of the received digital signal and convert it into an image of the laryngeal tissue structure.

Preferably, the ultrasonic linear array transducer is placed on the surface of the neck of the subject along the coronal plane or placed on the surface of the neck of the subject along the cross section.

Preferably, the imaging frame rate of the digital ultrasonic imaging system is 5000 frames per second, and the center frequency of the ultrasonic linear array transducer is 7.2 MHz.

Preferably, the ultrasonic linear array transducer is placed on the neck surface of the subject along the coronal plane; From the image, the vibration displacement of the vocal cords, the vibration displacement of the false vocal cords and the displacement of the initial vocal cords were extracted.

Preferably, the ultrasonic linear array transducer is placed on the surface of the subject's neck along the cross section; the computer is also used to extract vocal fold vibration feature points and vocal fold vibration phase parameters from the laryngeal tissue structure image.

A vocal cord vibration imaging method based on plane wave ultrasonic imaging, comprising the following steps: placing an ultrasonic linear array transducer on the skin surface of one side of the neck of the subject along the coronal plane and/or transverse plane, where the glottis is located ;The ultrasonic linear array transducer emits ultrasonic plane waves to the larynx, receives the echo, and transmits the echo to the data acquisition card; the data acquisition card converts the received echo signal into a digital signal and transmits it to the computer; the computer will receive The echo data of the digital signal is transformed into an image of the laryngeal tissue structure through beamforming, radio frequency signal envelope detection and dynamic range compression.

A method for measuring vocal cord vibration based on plane wave ultrasonic imaging, comprising the following steps: a computer collects an image of the tissue structure of the larynx, and a two-dimensional motion estimation algorithm based on ultrasonic radio frequency echo data is used to extract the vocal cord body from the image of the tissue structure of the throat Layer vibration displacement, false vocal cord vibration displacement and initial vocal cord displacement.

Preferably, the image of the tissue structure of the larynx is that the ultrasonic linear array transducer is placed on the skin surface of the subject's neck side along the coronal plane, where the glottis is located; Transmit ultrasonic plane waves, receive echoes, and transmit the echoes to the data acquisition card; the data acquisition card converts the received echo signals into digital signals and transmits them to the computer; the computer beams the echo data of the received digital signals Image resulting from synthesis, RF signal envelope detection and dynamic range compression conversion.

A method for measuring vocal cord vibration based on plane wave ultrasonic imaging, comprising the following steps: collecting the ultrasonic glottic graph curve UGG collected by an ultrasonic linear array transducer by a computer; A line segment connects these two positions; the position of this line is the midline of the glottis; then, a rectangle is selected as the region of interest ROI; the line segment of the position of the midline of the glottis is drawn as the symmetry axis of the rectangle; then, This rectangular region of interest ROI is divided into several equal parts along the length direction of the vocal folds; the pixel gray value of all pixels is extracted in each segmented region of interest ROI, and the pixel gray value of each segmented region of interest ROI is The time-varying ultrasound glottogram curve is calculated by formula (3):

$\mathrm{<span\; class="notranslate">\; UGG</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; the\; norm</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Among them, UGG(t) is the ultrasonic glottal graph curve changing with time, P _i,j (t) is the gray value of the pixel point (i,j) in a ROI at time t; N represents the gray value of the pixel in the ROI The number of all pixels in the image; 'norm' represents the normalization operation; the entire rectangular ROI is equally divided into M ROIs; the corresponding ultrasonic glottal graph curve is extracted for each segmented ROI;

From the corresponding ultrasonic glottogram curve extracted in each segmented ROI, find out the curve that the large amplitude and small amplitude regularly alternate in the curve; then add the found curves to obtain the global UGG curve of vocal fold vibration; The UGG curve is differentiated to obtain the DUGG curve, and then the D2UGG curve is calculated by formula (5);

D2UGG＝DUGG(n)|DUGG(n)| (5)

Through the peak detection algorithm, from the global UGG curve, the weakest point of the echo intensity in the glottis closing phase and the weakest echo intensity point in the glottis opening phase; the maximum moment of glottis opening is in the glottis opening phase of the global UGG curve The second zero-crossing point after the weakest point of the echo intensity; the time point of glottis closure is the first positive peak before the time corresponding to the weakest point of the echo intensity in the glottis closure phase in the D2UGG curve; the time point of glottis opening is the negative peak point of the D2UGG curve;

The glottic closure quotient CQ is calculated by formula (7):

$\mathrm{<span\; class="notranslate">\; CQ</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; Loc</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; Loc</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; eggs</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

Among them, Loc(F) represents the time position of the negative peak point in the D2UGG curve, Loc(G) represents the time position of the positive peak point in the _D2UGG curve, and Tegg represents the length of a vibration cycle.

Preferably, the ultrasonic glottis graph UGG is the position where the ultrasonic linear array transducer is placed on the skin surface of the subject's neck side along the cross section, where the glottis is located; the ultrasonic linear array transducer emits ultrasound Plane wave, receive the echo, and transmit the echo to the data acquisition card; the data acquisition card converts the received echo signal into a digital signal and transmits it to the computer to obtain the time-varying echo intensity curve.

Compared with the prior art, the present invention has the following beneficial effects:

1. Vocal fold tissue vibration imaging method based on plane wave ultrasound imaging technology synchronized with electroglottogram

To establish a non-invasive imaging and detection system, in which the PWU can achieve spatially synchronized imaging of vocal cord vibrations, while achieving very high temporal resolution, meeting the requirements for quantitative imaging of vocal cord vibrations.

Firstly, in order to overcome the motion blur problem existing in conventional ultrasonic imaging, the present invention abandons the linear scanning method adopted in conventional ultrasonic imaging technology, and adopts a plane wave emission method. By emitting a planar ultrasonic wave to cover a large area of the larynx, images of the tissue structure of the larynx in the entire imaging plane can be obtained. In the direction perpendicular to the sound beam, the images of each part are acquired simultaneously, so the sampling time difference between scanning lines that occurs in conventional ultrasonic imaging techniques is largely avoided. In turn, the motion blur problem of vocal cord tissue vibration imaging is greatly reduced. The imaging frame rate of this method can reach 7000 frames per second, which is much higher than the vibration frequency of the vocal cords, and can be used to study the non-periodic irregular vibration of the vocal cords in the case of unsteady vocalization.

During imaging, an ultrasound linear array transducer is placed on the side of the subject's neck, where the vocal cords are. According to the ultrasound image, the laryngeal tissue structures such as vocal cords and false vocal cords can be identified. By adjusting the position and angle of the transducer, the operator obtains images of the tissue structure of the coronal and horizontal planes of the vocal cords. When the subjects utter vowels, the PWU imaging technology is used to collect the original echo data of the high-speed vibration of the vocal cords. After beamforming, radio frequency signal envelope detection and dynamic range compression, the echo data is converted into an image of the laryngeal tissue structure.

2. Vibration measurement and imaging method of vocal cords and upper and lower glottis tissues based on plane wave radio frequency data two-dimensional motion estimation algorithm:

The original echo data is processed by a two-dimensional motion estimation algorithm based on radio frequency data, and the vibration velocity vector and displacement of the vocal cord tissue in the coronal plane are obtained. The vibration of the vocal cord tissue causes a delay in the data of adjacent frames. By estimating the time delay, the displacement vector of the tissue during the sampling interval can be inversely obtained. The vibration velocity of the vocal cord tissue is obtained by removing bits and sampling interval time. Compared with other motion estimation algorithms based on beamformed RF data, the algorithm has higher resolution of lateral displacement, which can detect smaller amplitude tissue vibrations. On the basis of obtaining the velocity and displacement of tissue vibration, the frequency and amplitude of vocal cord tissue vibration can be further obtained.

This method can not only image and measure the quasi-periodic vibration of the vocal cords under steady-state vocalization conditions, but also image and measure the non-periodic irregular vibrations of the vocal cords under unsteady-state vocalization conditions. At the same time, the imaging field of view of this method is wide, so it can also measure the vibration of the upper and lower glottis and the tissues around the vocal cords, such as the vibration of false vocal cords.

3 Segmentable Ultrasonic Glottograph Method Based on Plane Wave Ultrasound Imaging Technology

A UGG curve extraction method based on PWU is proposed. The location of the anterior commissure and the spoon cartilage was first determined on the ultrasound image of the transverse section of the vocal cords, and then the midline of the glottis was determined by connecting these two locations. Select a region of interest (ROI) with the glottic midline as the axis of symmetry, and divide the region into several small ROIs as required. Then calculate the ultrasonic echo signal intensity changing with time in each ROI, and obtain the global UGG curve of the entire vocal cord along the vocal cord length direction and the segmental UGG curve of specific parts of the vocal cord.

4. Segmentable ultrasonic glottis feature points and feature parameter extraction

The characteristic points of the vocal cord vibration can be extracted from the UGG curve through the peak detection algorithm and the zero-crossing detection algorithm: the maximum opening moment of the glottis, the closing moment of the glottis and the opening moment of the glottis. The glottic closure quotient is an important phase parameter of vocal fold vibration, which represents the ratio of vocal fold closure time to the entire vocal fold vibration period. In the past, the reliability of the method of determining the vocal cord closure time by extracting the positive and negative peaks of the DEGG curve would be affected by the inconspicuous negative peak of the DEGG curve, resulting in a decrease in the accuracy of the measured closure quotient. The negative peak of the UGG curve in the ultrasonic glottograph method proposed by the present invention is very obvious and prominent, and the reliability of extraction is very high. Therefore, in the present invention, it is proposed to combine the electroglottic graph method and the ultrasonic glottic graph method to extract the glottis closure quotient, and calculate the closure quotient by extracting the positive peak of the DEGG curve and the negative peak of the DUGG curve, thereby improving the glottis closure quotient The accuracy of extraction of this important phase parameter of vocal fold vibration.

The non-invasiveness of the imaging and detection method of the present invention minimizes interference with vocalization and ensures that the subject can vocalize with natural speech and dynamic speech.

Plane wave imaging technology can eliminate the spatial asynchrony of vocal fold vibration imaging, and the fixed-point synchronization of electroglottogram eliminates the temporal randomness of ultrasonic acquisition of vocal fold vibration. Therefore, the present invention can realize the time-space synchronization of vocal cord vibration detection.

The invention can comprehensively quantify and extract the motion information, feature point information and feature parameter information of the vocal cords and their surrounding tissues.

【Description of drawings】

Fig. 1 is the flowchart of the vocal fold vibration imaging and measurement method based on plane wave ultrasonic imaging;

Fig. 2 is a schematic diagram of the placement position of the ultrasonic transducer along the coronal plane;

Figure 3(a) is a schematic diagram of a two-dimensional motion estimation algorithm based on ultrasonic radio frequency echo data;

Fig. 3(b) is a schematic diagram of echo data being converted into an image of laryngeal tissue structure;

Fig. 3 (c) is the vibration displacement curve diagram of vocal cord tissue;

Figure 4(a) is a schematic diagram of a vocal cord vibration imaging and measurement system based on plane wave ultrasonic imaging;

Figure 4(b) is a schematic diagram of the relative positional relationship between the ultrasonic transducer, the vocal cords and surrounding tissue structures;

Figure 4(c) is a schematic diagram of the positional relationship between the transducer and the electrodes;

Figure 5(a) is a schematic diagram of the identification of the region of interest (the position of the anterior commissure and the spoon-shaped cartilage);

Figure 5(b) is a schematic diagram of the division of the region of interest (the location of the anterior commissure and spoon cartilage);

Fig. 6 is the segmented ultrasound glottogram curve and synchronous electroglottogram curve;

Fig. 7 is the global ultrasound glottogram curve and the synchronous electroglottogram curve.

【detailed description】

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Please refer to Fig. 1 to Fig. 7, a kind of vocal fold vibration imaging and measurement system based on plane wave ultrasonic imaging of the present invention includes a digital ultrasonic imaging system, a data acquisition card and a computer; the digital ultrasonic imaging system includes an ultrasonic linear array transducer device and host.

The ultrasonic linear array transducer is used to send out ultrasonic plane waves under the control of the host, and receive the echo, and return the echo to the host; the host outputs the echo to the data acquisition card, and the data acquisition card is used to receive the received The echo signal is converted into a digital signal and sent to the computer; the computer is used to perform beamforming, radio frequency signal envelope detection and dynamic range compression on the received echo data to convert the echo data of the digital signal into an image of the laryngeal tissue structure.

1. The overall process of the technical solution

Please refer to FIG. 1 , which is a schematic diagram of the overall technical solution of the method of the present invention. The vocal cord vibration imaging and measurement system based on plane wave ultrasonic imaging can work in two modes. When the ultrasonic linear array transducer is placed on the surface of the human neck along the coronal plane, the vibration displacement image of the vocal cords can be obtained through the displacement estimation algorithm. Furthermore, parameters such as the vibration displacement of the vocal cord body layer, the vibration displacement of the false vocal cord, and the displacement of the initial vocal cord can be quantified and extracted. When the ultrasonic linear array transducer is placed on the surface of the human neck along the cross section, the UGG curve of the entire vocal cord area and specific vocal cord tissue area can be obtained by calculating the signal echo intensity at the glottis, and then the vocal cord vibration feature points and Vocal fold vibration phase parameters are quantitatively extracted and measured.

2. Coronal imaging of the vocal cords

Figure 2 shows the anatomical diagram of the location of the ultrasonic linear array transducer and the coronal structure of the laryngeal tissue during coronal imaging of the vocal cords. The long arrows indicate the position of the false vocal cords, and the short arrows indicate the position of the vocal cords. On the left side of FIG. 2 , an x-z coordinate system is marked, the x-axis represents the vertical direction, and the z-axis represents the horizontal direction. The ultrasonic linear array transducer is placed on the skin surface of the subject's neck side, where the larynx is located. The vocal cords are the smallest organs in the body and lie beneath the thyroid cartilage. Therefore, in actual operation, in order to allow the ultrasonic signal to penetrate the thyroid cartilage while ensuring sufficient resolution of the image, an ultrasonic linear array transducer with a center frequency of 7.2 MHz is used. The fundamental vibration frequency of the vocal cords ranges from tens of hertz to hundreds of hertz, so in order to satisfy the Nyquist sampling theorem, the imaging frame rate is generally set to 5000 frames per second. In addition, it is not recommended to use a higher imaging frame rate because the high imaging frame rate will cause the ultrasonic linear array transducer to overheat and be damaged.

Under the excitation of the ultrasonic transmitting end, the ultrasonic linear array transducer emits a single pulse ultrasonic plane wave with a width of 38 mm and a pulse period of 125 nanoseconds to the throat. Ultrasonic plane waves scatter when they encounter tissue, producing echoes in the opposite direction of the transmitted wave. These echoes will be received by the ultrasonic linear array transducer, and the echo signals will be converted into digital signals by multi-channel radio frequency data acquisition equipment and stored in the computer hard disk. After beamforming, radio frequency signal envelope detection and dynamic range compression, the echo data stored in the computer hard disk is converted into an image of the laryngeal tissue structure, as shown in Figure 3(b). In Figure 3(b), the long arrows indicate the position of the false vocal cords, and the short arrows indicate the positions of the vocal cords. Because ultrasound cannot penetrate the air between the vocal cords on both sides, we can only observe the vocal cords on one side in Figure 3(b).

3. Tissue Vibration Measurement

The invention can measure the vibration speed and displacement of the vocal cord tissue while imaging the vocal cord vibration. Here we employ a 2D motion estimation algorithm based on ultrasound RF echo data.

Figure 3(a) is a schematic diagram of the algorithm. The goal of the algorithm is to measure the movement displacement and velocity of the tissue located at (x ₀ , z ₀ ) in the figure. It is assumed here that at the next sampling time, the tissue at this location moves to (x ₀ +dx, z ₀ +dz). During this sampling time, the displacement of the tissue is (dx,dz).

The first step of the algorithm: use the beamforming algorithm to obtain the tissue echo signals at (x ₀ , z ₀ ) received by the two sub-apertures on the transducer, which are named RF ₁ and RF ₂ respectively. The included angles between the two sub-apertures and the axis of the sound field are α ₁ and α ₂ . The movement of the tissue causes a delay in the echo signals RF ₁ and RF ₂ , named as and The relationship between delay and displacement can be written as:

$\begin{array}{c}{\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; dz</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; dz</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; dx</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; ,</span>\\ {\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; dz</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; dz</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; dx</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; .</span>\end{array}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

where c represents the sound propagation velocity in the tissue. Using the one-dimensional cross-correlation algorithm, we can find and Then the displacement of the tissue can be calculated inversely:

$\begin{array}{c}\mathrm{<span\; class="notranslate">\; dz</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; ,</span>\\ \mathrm{<span\; class="notranslate">\; dx</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; .</span>\end{array}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Given the imaging frame rate, the sampling interval can be obtained. Using this algorithm, the displacement of tissue at each grid point in the field of view can be calculated within the sampling interval. The average moving speed of the tissue within the sampling interval is obtained by removing bits by the sampling interval. Because the imaging frame rate is 5000 frames per second, the sampling interval is only 200 microseconds, which is much smaller than the vibration period of vocal cord tissue. Therefore, the average velocity of the tissue during the sampling interval approaches the instantaneous velocity of the tissue. By integrating the velocity, the vibration displacement curve of the vocal cord tissue can be obtained, as shown in Figure 3(c). By detecting the peaks and valleys of the curve, the vibration period and fundamental frequency of the vocal cords, as well as the vibration amplitude of the vocal cord tissues can be calculated.

4. Vocal cord imaging along the cross section

Firstly, let the digital ultrasound imaging system work in B mode to facilitate clear imaging. After coupling, the ultrasonic linear array transducer was placed on the skin surface of the subject's neck side along the cross section, at the height of the subject's glottis. Then the angle and position of the ultrasound linear array transducers were adjusted minutely and carefully until the images of the anterior commissure and the spoon cartilage could be observed simultaneously on the display screen of the digital ultrasound imaging system. Figure 4(b) is a schematic diagram showing the relative positional relationship between the ultrasonic transducer, the vocal cords and surrounding tissue structures. The outermost layer S is the skin, T is the thyroid cartilage, and V is the vocal cords. The fusion of the vocal cords on both sides presents the attachment of the tendons of the vocal cords to the thyroid cartilage, called the anterior commissure (AC). The space between the vocal cords on both sides is called the glottic fissure, or glottis (G) for short. Posterior A shows the spoon cartilage. When we observe both the anterior commissure and the spoon-shaped cartilage on the screen of the ultrasound system, it means that the entire vocal cord along the length of the vocal cord has entered the imaging range.

After finding the position of the anterior commissure and the spoon-shaped cartilage, adjust the imaging mode of the digital ultrasound imaging system to plane wave imaging. The specific imaging parameters are the same as the above "Coronal imaging of the vocal cords", that is, the emission width to the larynx is 38 Single-pulse ultrasonic plane wave in millimeters with a pulse period of 125 nanoseconds. One EGG electrode was placed on the cervical surface above the transducer, and the other EGG electrode was placed in an obliquely downward position on the contralateral neck. The two EGG electrodes were placed 1 cm above and below the height of the glottis, as shown in Figure 4(b) and 4(c). Note that the placement of the EGG electrode should avoid the path of the ultrasonic beam propagation, so as not to affect the ultrasonic echo signal. The subject made a sound while the experimenter pressed the record button of the digital ultrasound imaging system to record the ultrasound RF data. At the same time, the external trigger signal sent by the digital ultrasound imaging system will make the electroglottograph record the electroglottograph signal synchronously. The entire acquisition process lasts about 250ms. This recording time typically consists of several tens of cycles of vocal cord vibration. All RF data and electroglottogram data were stored in a computer for subsequent off-line processing.

5. Ultrasonic glottis curve extraction method

Figure 5 shows a frame of plane wave ultrasound images along the front-back direction of the vocal cords. When the vocal cords are separated by the airflow from the lungs to create the glottis, an air-tissue interface forms at the edge of the vocal cords. The vocal cords vibrate periodically, and the glottis also appears and disappears periodically. Since the gas-tissue interface will strongly reflect the ultrasonic signal, the strong reflected echo signal that periodically appears and disappears can be observed on the display screen of the ultrasonic system, and it is displayed as a bright line in the obtained ultrasonic image sequence. The line segments appear and disappear periodically. At either end of this line segment are two brighter regions. These two bright areas exist in all ultrasound image sequences, and their positions are relatively fixed. These two bright areas are where the anterior commissure and spoon cartilage are located, as indicated by the arrows in Figure 5(a). The bright line between them is the echo signal of the gas-tissue interface of the vocal cords. Ultrasonic PWU technology can overcome the asynchrony of traditional line scan imaging in space, so the vocal fold vibration signal along the entire length of the vocal cord can be obtained simultaneously by measuring the amplitude of the ultrasonic echo signal in the glottis region. The measured time-varying echo intensity curve is the UGG curve.

First, the positions of the anterior commissure and the spoon cartilage were judged subjectively, and then manually connected by a line segment on the ultrasound image. The location of this line is considered to be the midglottic line. Due to the variability of the shape of the glottis and the reverberation effect of ultrasound, the hyperechoic ultrasound signal at the gas-tissue interface appears as a line segment with a certain width in the ultrasound picture. Therefore, a rectangle is selected as a region of interest (ROI), and the width of this rectangle ROI is 1-5 mm. The line segment drawn at the position of the midline of the glottis serves as the axis of symmetry of this rectangle. Subsequently, this rectangular ROI is divided into several equal parts along the length direction of the vocal cords, as shown in Fig. 5(b). Extract the pixel gray values of all pixels in the region of interest ROI of each segment, then the ultrasonic glottogram curve changing with time in the region of interest ROI of each segment is calculated by formula (3):

$\mathrm{<span\; class="notranslate">\; UGG</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; the\; norm</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Here UGG(t) is the time-varying ultrasound glottal graph curve, and P _i,j (t) is the gray value of a pixel point (i,j) in a certain ROI at time t. N represents the number of all pixels in the ROI. 'norm' stands for normalization operation. The entire rectangular ROI is equally divided into M ROIs. Corresponding echoglottogram curves were extracted for each segmented ROI.

Figure 6 shows the segmental UGG curves in ten segmental ROIs from the anterior commissure to the vocal cord between the spoon-shaped cartilages. The part with large amplitude in the curve represents weak ultrasonic echo signal intensity, while the part with small amplitude represents strong echo signal.

Since the position of the anterior commissure and the position of the spoon-shaped cartilage are determined subjectively, and the two anatomical structures themselves have a certain volume, not all the ultrasonic glottic graph curves in the extracted segmental ROIs are Reflect the results of vocal cord movement. When the two sides of the vocal cords are in contact, the ultrasonic beam can transmit the tissue in contact with the vocal cords; while when the two sides of the vocal cords are separated, most of the ultrasonic signal will be reflected back by the tissue-gas interface. Therefore, the ultrasonic glottograph curve describing the vibration of the vocal cords should have large and small amplitudes alternately appearing in a certain law and order. Observing the segmented ultrasonic glottal graph curves in Figure 6, it is found that the five curves of Seg3, Seg4, Seg5, Seg6, and Seg7 are in line with the characteristics of the influence of vocal fold vibration on ultrasonic echo. The global UGG curve of vocal cord vibration can be obtained by summing the curves conforming to the characteristics, as shown in the UGG (global) curve in FIG. 7 . The synchronous EGG curves are also given in Fig. 7. The EGG signal is differentiated through a differential operation to obtain the DEGG curve, and then the D2EGG curve is calculated by formula (4). Similarly, the DUGG curve can be obtained by performing differential operations on the UGG curve, and then the D2UGG curve is calculated by formula (5).

D2EGG＝DEGG(n)|DEGG(n)| (4)

D2UGG＝DUGG(n)|DUGG(n)| (5)

6. Extraction of feature points and feature parameters of ultrasound glottis

The characteristic points of the electroglottogram curve can reflect the very important phase moments in the vocal cord vibration process. The maximum glottis opening time point A in the EGG curve and the glottis closing time point G and glottis opening time point H in the D2EGG are extracted by a peak detection algorithm. At the same time, the corresponding feature points are extracted from the UGG curve. By controlling the search window length of the peak detection algorithm, the weakest point C of the echo intensity in the glottis closed phase and the weakest point D of the echo intensity in the glottis open phase are obtained from the global UGG curve. Point B is a small but obvious fluctuation peak in each period of the global UGG curve, and point B of each period can be extracted by looking for the second zero-crossing point after point D. Point E is a small positive peak in the D2UGG curve, and the extracted point E is the first positive peak before the time corresponding to point C. Point F is the negative peak point of the D2UGG curve. This negative peak point is very prominent and easily identified by the peak detection algorithm.

In the EGG curve, point A is the valley point of the electroglottogram curve, which represents the moment when the glottis is the most open; in the UGG curve, in the opening phase of the vocal cords, although the global UGG curve amplitude is relatively low, it is still There is an obvious fluctuation, and the marked point B is the apex of this fluctuation peak. It represents the moment when the reflected echo at the midline of the glottis is the weakest after the vocal cords move to both sides after the glottis is opened, so the moment at point B is also the moment when the glottis is most open.

The midpoint G of the D2EGG curve is the positive peak point of the D2EGG curve, which represents the moment when the glottis just closes; H is the negative peak point of the D2EGG curve, which represents the moment when the glottis just opens. Point E and point F in the D2UGG curve are positive peak point and negative peak point respectively, which also represent the same meaning of vibration phase.

The glottal closure quotient (CQ) refers to the ratio of the time during which the glottis is completely closed to the entire vibration cycle. Usually CQ is extracted from the D2EGG curve alone, such as formula (6):

$\mathrm{<span\; class="notranslate">\; CQ</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; Loc</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; Loc</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; eggs</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

Among them, Loc represents the time position of the point, and _Tegg represents the length of a vibration cycle.

However, in many cases, the positive peak of the D2EGG curve is obvious, while the negative peak is not obvious, or even unrecognizable. However, the negative peak in the D2UGG curve is very significant. Therefore, extracting the positive peak of the D2EGG curve and the positive peak of the D2UGG curve can obtain more accurate and reliable CQ. Calculate as formula (7):

$\mathrm{<span\; class="notranslate">\; CQ</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; Loc</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; Loc</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; eggs</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

Therefore, combining the advantages of ultrasound glottogram and electroglottogram can obtain more accurate and reliable vocal cord vibration parameters.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements, without departing from the spirit and scope of the technical solution, should be included in the scope of the claims of the present invention.

Claims (8)

1. A vocal cord vibration imaging and measurement system based on plane wave ultrasonic imaging, characterized in that it includes a digital ultrasonic imaging system, a data acquisition card and a computer; the digital ultrasonic imaging system includes an ultrasonic linear array transducer and a mainframe; The ultrasonic linear array transducer is used to emit ultrasonic plane waves under the control of the host, receive the echo, and transmit the echo back to the host; The host is used to control the ultrasonic linear array transducer to emit ultrasonic plane waves, and output the echoes to the data acquisition card; The data acquisition card is used to convert the received echo signal into a digital signal and transmit it to the computer; The computer is used to convert the echo data of the received digital signal into beamforming, radio frequency signal envelope detection and dynamic range compression into laryngeal tissue structure images; The ultrasonic linear array transducer is placed on the surface of the subject's neck along the coronal plane or placed on the surface of the subject's neck along the cross section; The imaging frame rate of the digital ultrasonic imaging system is 5000 frames per second, and the center frequency of the ultrasonic linear array transducer is 7.2MHz. 2. a kind of vocal cord vibration imaging and measurement system based on plane wave ultrasonic imaging according to claim 1, is characterized in that, described ultrasonic linear array transducer is placed on the neck surface of the subject along the coronal plane; A two-dimensional motion estimation algorithm based on ultrasonic radio frequency echo data is also used to extract the vocal cord layer vibration displacement, false vocal cord vibration displacement and initial vocal cord displacement from the laryngeal tissue structure image. 3. a kind of vocal cord vibration imaging and measuring system based on plane wave ultrasonic imaging according to claim 1, is characterized in that, described ultrasonic linear array transducer is placed on the neck surface of the subject along the cross section; It is also used to extract vocal fold vibration feature points and vocal fold vibration phase parameters from the laryngeal tissue structure image. 4. A vocal cord vibration imaging method based on plane wave ultrasonic imaging, characterized in that, based on a kind of vocal cord vibration imaging and measurement system based on plane wave ultrasonic imaging according to claim 1, comprising the following steps: Place the ultrasonic linear array transducer on the skin surface of the subject's neck side along the coronal plane and/or transverse section, where the glottis is located; the ultrasonic linear array transducer emits ultrasonic plane waves to the larynx and receives Echo, transmit the echo to the data acquisition card; the data acquisition card converts the received echo signal into a digital signal and transmits it to the computer; the computer performs beamforming and radio frequency signal envelope on the echo data of the received digital signal Detection and dynamic range compression are converted to images of laryngeal tissue structures. 5. A method for measuring vocal cord vibration based on plane wave ultrasonic imaging, characterized in that, based on the vocal cord vibration imaging and measurement system based on plane wave ultrasonic imaging according to claim 1, comprising the following steps: computer acquisition laryngeal tissue structure image , using a two-dimensional motion estimation algorithm based on ultrasonic radio frequency echo data to extract the vocal cord tomographic vibration displacement, the false vocal cord vibration displacement and the initial vocal cord displacement from the laryngeal tissue structure image. 6. A method for measuring vocal cord vibration based on plane wave ultrasonic imaging according to claim 5, wherein the laryngeal tissue structure image is that an ultrasonic linear array transducer is placed on the subject's neck along the coronal plane. The surface of the skin on the side of the throat, where the glottis is located; the ultrasonic linear array transducer emits ultrasonic plane waves to the larynx, receives echoes, and transmits the echoes to the data acquisition card; the data acquisition card receives the echo signals It is converted into a digital signal and sent to the computer; the computer performs beamforming, radio frequency signal envelope detection and dynamic range compression conversion on the echo data of the received digital signal to form an image. 7. A vocal cord vibration measurement method based on plane wave ultrasonic imaging, characterized in that, based on claim 1, a vocal cord vibration imaging and measurement system based on plane wave ultrasonic imaging, comprising the following steps: computer acquisition of ultrasonic linear array transduced energy Ultrasonic glottic graph curve UGG collected by the instrument; determine the position of the anterior commissure and spoon-shaped cartilage, and then connect these two positions with a line segment on the ultrasonic image; the position of this line is the midline of the glottis; then, select Define a rectangle as the region of interest ROI; draw the line segment of the midline position of the glottis as the symmetry axis of the rectangle; then, the rectangular region of interest ROI is divided into several equal parts along the length of the vocal cords; in each The pixel gray values of all pixels are extracted in the segmented region of interest ROI, and the ultrasonic glottogram curve changing with time in each segmented region of interest ROI is calculated by formula (3): $\mathrm{<span\; class="notranslate">\; u</span>}\mathrm{<span\; class="notranslate">\; G</span>}\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$ Among them, UGG(t) is the ultrasonic glottal graph curve changing with time, P _i,j (t) is the gray value of the pixel point (i,j) in a ROI at time t; N represents the gray value of the pixel in the ROI The number of all pixels in the image; 'norm' represents the normalization operation; the entire rectangular ROI is equally divided into M ROIs; the corresponding ultrasonic glottal graph curve is extracted for each segmented ROI; From the corresponding ultrasonic glottogram curve extracted in each segmented ROI, find out the curve that the large amplitude and small amplitude regularly alternate in the curve; then add the found curves to obtain the global UGG curve of vocal fold vibration; The UGG curve is differentiated to obtain the DUGG curve, and then the D2UGG curve is calculated by formula (5); D2UGG＝DUGG(n)|DUGG(n)| (5) In formula (5), n refers to the sampling time of ultrasound, n=1,2,3...; where, DUGG(n) is the differential of UGG(n), |DUGG(n)| is the absolute value of DUGG(n) ; Through the peak detection algorithm, from the global UGG curve, the weakest point of the echo intensity in the glottis closing phase and the weakest point of the echo intensity in the glottis opening phase; the maximum moment of glottis opening is in the glottis opening phase of the global UGG curve The second zero-crossing point after the weakest point of the echo intensity; the time point of glottis closure is the first positive peak before the time corresponding to the weakest point of the echo intensity in the glottis closure phase in the D2UGG curve; the time point of glottis opening is the negative peak point of the D2UGG curve; The glottic closure quotient CQ is calculated by formula (7): $\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; g</span>}\mathrm{<span\; class="notranslate">\; g</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$ Among them, Loc(F) represents the time position of the negative peak point in the D2UGG curve, Loc(G) represents the time position of the positive peak point in the _D2UGG curve, and Tegg represents the length of a vibration cycle. 8. A kind of vocal cord vibration measurement method based on plane wave ultrasonic imaging according to claim 7, characterized in that, the ultrasonic glottograph curve UGG is the ultrasonic linear array transducer placed on the subject's side along the cross section. The skin surface on one side of the neck, where the glottis is located; the ultrasonic linear array transducer emits ultrasonic plane waves, receives echoes, and transmits the echoes to the data acquisition card; the data acquisition card converts the received echo signals into The digital signal is sent to the computer to obtain the time-varying echo intensity curve.