Direct wave suppression method and system for microwave imaging system

Abstract

The present invention provides a direct wave suppression method and system of a microwave imaging system, by performing frequency-domain to time-domain conversion on an echo signal set composed of echo signals obtained by a vertical linear array antenna at all equivalent antenna collection positions, A series of filtering operations such as filtering, time-domain to frequency-domain conversion, and subtraction and subtraction can effectively suppress the interference generated by the direct wave signal, thereby improving the sensitivity of the echo signal receiver, simplifying the subsequent imaging processing process, and improving The imaging performance of the microwave imaging system is improved, so that an accurate image of the target object can be obtained.

Description

technical field [0001] Embodiments of the present invention belong to the technical field of microwave imaging, and in particular relate to a direct wave suppression method and system for a microwave imaging system. Background technique [0002] Microwave imaging technology uses the method of actively emitting electromagnetic waves in the microwave band to scan and image objects, because it can penetrate the surface of objects to detect metal or non-metal contraband hidden inside the object, and because it has a small radiation dose and is non-ionizing Radiation and other characteristics, it is widely used in microwave imaging systems such as security detectors to perform human security inspection tasks. The current popular microwave imaging technology usually needs to obtain the echo signals at all equivalent antenna collection positions through the linear array antenna to form an echo signal set, and then send the echo signal set to the signal processing equipment of the s...

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Problems solved by technology

[0004] Embodiments of the present invention provide a direct wave suppression method and system for a microwave imaging system, aiming to solve the problem that in practical applications, part of the direct wave signal is included in the echo signal obtained by the linear array antenna at the equivalent antenna collection position. The energy of the direct wave signal in the wave signal is several orders of magnitude larger than the echo energy reflected by the target object. If the direct wave signal is not suppressed or filtered, the sensitivity of the echo signal receiver will be reduced, resulting in saturation or even damage to the front end of the receiver. It increases the difficulty of the subsequent imaging process and reduces the imaging performance of the microwave imaging system, making it impossible to obtain accurate images of the target object

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