A Doppler Measurement Method Based on Envelope of Ultrasonic Transducer
An ultrasonic transducer and measurement method technology, applied in the field of Doppler measurement, can solve the problems of reducing hardware and algorithm requirements, reducing sampling frequency, etc., and achieve the effect of reducing hardware requirements and algorithm requirements.
Active Publication Date: 2021-01-01
ZHEJIANG UNIV
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Problems solved by technology
[0003] The purpose of the present invention is to solve the need to carry out short-time Fourier transform or wavelet transform to the echo signal to calculate the actual motion speed when the pulse-echo measurement requires higher sampling frequency and specific signal processing parameters. The ultrasonic Doppler measurement method based on the envelope reduces the sampling frequency and greatly reduces the requirements for hardware and algorithms
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[0021] The present invention will be further elaborated and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of the various implementations in the present invention can be combined accordingly on the premise that there is no conflict with each other.
[0022] Before discussing the specific implementation process of the present invention, first introduce its technical principle.
[0023] In this method, by analyzing the dynamic model of the ultrasonic transducer in the pulse-echo mode, the solution of the oscillation system of the ultrasonic transducer under the condition of underdamping is calculated, so as to obtain the envelope of the vibration displacement equation. Then through the dynamic response envelope of the ultrasonic transducer under different excitation frequencies. It is observed that the position of the concave-convex point in the response curve at the non-resonant frequency is only related to the...
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The invention discloses an envelope line based ultrasonic Doppler measurement method of an ultrasonic transducer. The method comprises the following steps: 1) for a first ultrasonic transducer, undernonresonant frequency excitation, transmitting ultrasonic pulses to a to-be-measured moving object, and by a second ultrasonic transducer, receiving echo signal vibration amplitude curve reflected bythe moving object; 2) performing envelope line extraction for the echo signal vibration amplitude curve, determining positions of the k convex point and the k concave point on the envelope line, and obtaining corresponding time difference Tk of the k convex point and the k concave point; 3) calculating frequency shift according to the time difference Tk; 4) determining whether the frequency shiftbelongs to positive shift or negative shift, and finally obtaining shifted frequency f; 5) according to the shifted frequency f, calculating speed of the moving object according to an ultrasonic Doppler measurement principle. The envelope line measurement method provided by the invention greatly reduces requirements on hardware and requirements on algorithms.
Description
technical field [0001] The invention relates to a Doppler measurement method for an ultrasonic transducer based on extracting a dynamic response envelope. Background technique [0002] Ultrasonic velocity measurement generally uses the Doppler effect of ultrasound to measure the velocity of an object. When the ultrasonic wave encounters a moving object, the frequency will change, and the moving speed of the object can be determined by detecting the frequency change. Ultrasonic Doppler measurement mainly has two measurement methods, continuous wave measurement and pulse-echo (pulse-echo) measurement. The frequency band of continuous wave measurement is narrow, and it is susceptible to the influence of multiple loop reflections, which will cause large errors. Since continuous operation is not required, the pulse-echo method consumes relatively less power. And the pulse-echo method can adapt to different measurement ranges by controlling the measurement frame rate and adjust...
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IPC IPC(8): G01S15/58
CPCG01S15/582
Inventor 谢金杨邓飞刘鑫鑫陈旭颖
Owner ZHEJIANG UNIV