Real-time calibration method for frequency-modulated continuous wave linearity in terahertz imaging and system thereof

Abstract

The invention discloses a real-time calibration method for frequency-modulated continuous wave linearity in terahertz imaging and a system thereof. The method comprises the following steps: mixing anecho signal reflected by a target to be measured with a terahertz signal to obtain a baseband signal; dividing the baseband signal into two paths for calibrating calculation, wherein one path filtersa coupling signal through band-pass filtering to obtain a baseband signal carrying target information, and the other path is used as real-time calibration data to calibrate each pulse in real time inthe calibrating calculation, filter random phase noise before the calibrating calculation and transform the acquired data into complex data. The invention can not only calibrate each pulse in real time to guarantee the timeliness of the calibration data and target echo data and realize the real-time calibration, but also filter out the coupled signal to ensure the sensitivity of the system. The invention has a good effect in terahertz imaging measurement with large random phase noise and high measurement accuracy requirements.

Description

technical field [0001] The invention belongs to the technical field of terahertz imaging, and in particular relates to a real-time calibration method and system for frequency modulation continuous wave linearity in terahertz imaging. Background technique [0002] Terahertz imaging technology has the advantages of high spatial resolution, strong anti-interference ability, and harmless to the human body. It is widely used in security inspection and anti-terrorism, medical diagnosis, atmospheric and environmental detection and other fields. Among terahertz imaging systems, terahertz FMCW radar has attracted extensive attention due to its ultra-high imaging resolution. Ideally, the frequency modulation slope of the signal in the radar system is a constant, the frequency of the transmitted signal changes linearly, and the range resolution of the radar is only related to the bandwidth of the transmitted signal. However, in actual situations, the FM slope of the sending and receiv...

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Problems solved by technology

[0008] Aiming at the deficiencies in the prior art and solving the problem of how to measure the calibration body and the measured object in real time at the same time in the prior art to obtain system linearity and compensate while ensuring the system sensitivity, the present invention provides a continuous frequency modulation in terahertz imaging The wave linearity real-time calibration method and its system can calibrate each pulse in real time, ensuring the time consistency of the calibration data and the target echo data, effectively realizing the real-time calibration, and filtering the coupling signal at the same time, ensuring the system sensitivity

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