Reflection window-based device and method for increasing terahertz wave imaging signal-to-noise ratio

A technology of terahertz wave imaging and terahertz wave off-axis, applied in the field of terahertz wave imaging, can solve the problems of large ratio of peak signal amplitude to noise level of time-domain data, difficulty in improving signal-to-noise ratio, and affecting imaging quality , to achieve the effect of improving the imaging signal intensity, improving the imaging signal-to-noise ratio, and improving the imaging quality

Pending Publication Date: 2019-03-12
TIANJIN UNIV
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

Pulse sources such as terahertz time-domain spectrometers can simultaneously measure the amplitude and phase information of objects, but because the energy is distributed over the entire bandwidth of the terahertz pulse, the signal-to-noise ratio (SNR) at narrowband frequencies is usually very low, and the peak signal amplitude The ratio to the noise level of the time-domain data can be very large, seriously affecting the image quality
[0005] At present, the method of recovering the original signal through the improved algorithm has also achieved certain results, but the calculation is cumbersome and only restores the output with a certain probability
Based on the reverse wave oscillator (BWO), Gunn oscillator, far-infrared laser pumped by CO2 laser, difference frequency source or parametric oscillation source, only the intensity information of the object can be obtained. By increasing the power of the terahertz radiation source at a certain To a certain extent, the influence of noise from the external environment is reduced, but for samples with large absorption, the signal-to-noise ratio is difficult to improve

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  • Reflection window-based device and method for increasing terahertz wave imaging signal-to-noise ratio
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  • Reflection window-based device and method for increasing terahertz wave imaging signal-to-noise ratio

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Embodiment 1

[0047] An embodiment of the present invention provides a device for improving the signal-to-noise ratio of terahertz wave imaging based on the reflection window, see figure 1 , the device includes: a terahertz radiation source 1, a detector 2 receiving the terahertz radiation source, a first terahertz wave off-axis parabolic mirror 3, a second terahertz wave off-axis parabolic mirror 4, a third terahertz wave off-axis parabolic mirror a parabolic mirror 5, a terahertz wave plane mirror 6, and a reflection window 7,

[0048] Wherein, the reflective window 7 is a material highly transparent to terahertz waves, which is fixed on the two-dimensional scanning platform for placing the imaging sample to be measured;

[0049] The terahertz wave plane reflector 6, the first terahertz wave off-axis parabolic mirror 3, the second terahertz wave off-axis parabolic mirror 4, and the third terahertz wave off-axis parabolic mirror 5 are sequentially arranged on the outgoing light path of the...

Embodiment 2

[0059] An embodiment of the present invention provides a method for improving the signal-to-noise ratio of terahertz wave imaging based on a reflection window, and the method is realized by using a reflection window. Since the signal strength of the terahertz wave reflected multiple times in the reflection window decreases gradually, the signal received by the terahertz wave reflective imaging only considers the terahertz wave reflected for the first time by the first reflection window surface 21 and the second reflection window surface 22 composition, i.e. I 1 and I 2 , the optical path diagram of the terahertz wave in the reflection window, such as figure 2 shown.

[0060] Among them, I 0 is the angle of incidence θ 0 The incident intensity of the terahertz wave, I 1 is the incident light I 0 The reflected light intensity at the first reflective window surface 21, I 2 is the reflected light intensity of the incident light transmitted through the first reflective wind...

Embodiment 3

[0073] Combine below image 3 Carry out feasibility verification to the scheme, working principle in embodiment 1, see the following description for details:

[0074] The purpose of the embodiments of the present invention is to provide a method for improving the imaging signal-to-noise ratio and reducing the influence of external noise on terahertz wave reflective imaging during the data acquisition stage.

[0075] In this example, the reflective imaging signal-to-noise ratio is calculated by applying reflective windows with different thicknesses to scan and image the gold-plated reflector. When the terahertz frequency is 2.52THz, the signal-to-noise ratio of a horizontal line scanning on the gold-plated mirror, such as image 3 shown.

[0076] Terahertz source produces terahertz wave output, terahertz wave (intensity is I 0 ) with θ 0 The angle is incident on the first reflection window surface 21, and a part of the terahertz wave is reflected by the first reflection win...

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Abstract

The invention discloses a reflection window-based device and method for increasing a terahertz wave imaging signal-to-noise ratio. The device only adopts a reflection window for reducing defects suchas Fresnel reflection and non-uniform diffuse scattering of an object to increase a signal amplitude and increase the imaging signal-to-noise ratio to the maximum extent. According to the device and method, the interference theory is applied into reflection type imaging to select an appropriate reflection window thickness through theoretical calculation so as to realize enhancement of the imagingsignal strength and increase the imaging signal-to-noise ratio; and the device is simple, convenient and high in imaging quality.

Description

technical field [0001] The invention relates to the field of terahertz wave imaging, in particular to a device and method for improving the signal-to-noise ratio of terahertz wave imaging based on a reflection window. Background technique [0002] Terahertz (Terahertz, referred to as THz, 1THz = 10 12 Hz) radiation refers to the frequency range from 0.1THz to 10THz, the corresponding wavelength is from 3 mm to 30 microns, and the electromagnetic spectrum range is quite wide between millimeter wave and infrared light. The special position of terahertz radiation in the electromagnetic spectrum endows it with a series of special properties, which makes terahertz technology applicable to biomedical detection, material property research, security inspection and other fields. Among terahertz wave-related technologies, terahertz wave imaging, as one of its research hotspots, has achieved a series of results. At present, in the field of biomedicine, terahertz wave imaging technolo...

Claims

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Application Information

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IPC IPC(8): G01N21/55
CPCG01N21/55
Inventor 徐德刚武丽敏王与烨姚建铨
Owner TIANJIN UNIV
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