Quasi one-time orthogonal complementary Golay (A,B) code ultrasonic phased array coded excitation method

Abstract

The invention discloses a quasi one-time orthogonal complementary Golay (A,B) code ultrasonic phased array coded excitation method. The method comprises the following steps: coded excitation is carried out by Golay A code; Golay A to B code excitation transition of received echo is realized by software algorithm, and twice stimulated echoes of Golay A,B are obtained (orthogonal complementary Golay coded excitation condition is formed); pulse compression is carried out, decoding is realized by summarizing vectors, so that quasi one-time orthogonal complementary Golay coded excitation technology is realized, and replaces the traditional double-emission scheme with physical hardware. An effective noise inhibition-deconvolution algorithm is used, FPGA(Field Programmable Gate Array) is used for realizing excitation transition algorithm of sequence Golay A code excitation to Golay B code, in order to realize the purpose of quasi one-time excitation; the traditional Golay A,B code separated excitation scheme is improved, operation efficiency of the phased array system is increased by 50%, signal to noise ratio (related to coding length Lc) is greatly improved, the problem of decoding effect influenced by inconsistent received waveforms due to position changes of twice emissions in some dynamic scanning processes is avoided, and the method has an important application value in practical engineering.

Description

technical field [0001] The invention relates to a quasi-single orthogonal complementary Golay (A, B) code ultrasonic phased array coding excitation method. Background technique [0002] Among the key technologies of ultrasonic phased array system performance, improving the penetration and resolution of the instrument by enhancing the emission energy is one of the key technologies for industrial non-destructive testing, such as increasing the aperture of the transceiver, improving the matching circuit of the probe, and increasing the emission voltage. The hardware system becomes complex and the controllability deteriorates, which directly affects the stability and reliability of the instrument, while the coded excitation technology is used to transmit multiple continuous waves to indirectly enhance the transmission energy (the receiving end performs energy aggregation on low-voltage continuous waves) This problem can be avoided. Single excitation such as YannisS.Avrithis et ...

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Problems solved by technology

[0002] Among the key technologies of ultrasonic phased array system performance, improving the penetration and resolution of the instrument by enhancing the emission energy is one of the key technologies for industrial non-destructive testing, such as increasing the aperture of the transceiver, improving the matching circuit of the probe, and increasing the emission voltage. The hardware system becomes complex and the controllability deteriorates, which directly affects the stability and reliability of the instrument, while the coded excitation technology is used to transmit multiple continuous waves to indirectly enhance the transmission energy (the receiving end performs energy aggregation on low-voltage continuous waves) can avoid this problem

Single excitation such as YannisS.Avrithis et al. (1998) adopts CDMA (CodeDivisionMultipleAccess) pseudo-random coding to excite the ultrasound system, which has higher image acquisition rate, lateral resolution and contrast than traditional single-pulse excitation; Korean JeongJS. scholar (2013) used Barker coding technology suppresses the interference caused by high-intensity focused ultrasound up to -40dB; Scholars such as ByramB. of Vanderbilt University in the United States (2014) adopt Chirp code frequency modulation mode to effectively suppress the clutter of ultrasonic multipath and beamforming; but the above decoding effect is not ideal ( Horizontal sidelobe is generated, which cannot be restored to an ideal echo signal) and the transmitting circuit is complex

Double excitation, such as JinhyoungPark (2010) of University of California, using Golay code excitation technology and 6dB bandwidth amplifier, realizes ripple within 4dB in the 10-110MHz frequency band, reflecting excellent performance; University of Science and Technology of China (2010) uses Chirp signal modulation Golay complementary code excitation increases the penetration depth and anti-interference ability of medical ultrasound; Chinese Academy of Medical Sciences (2014) obtained a higher signal-to-noise ratio with a Golay complementary sequence of length 4; although the ideal decoding effect is achieved in theory, it takes two times Emission, low efficiency, poor reliability

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