Phase coherence factor for mitigation of sidelobe artifacts in through-the-wall radar imaging

2013 ◽  
Vol 27 (6) ◽  
pp. 716-725 ◽  
Author(s):  
Biying Lu ◽  
Xin Sun ◽  
Yang Zhao ◽  
Zhimin Zhou
Keyword(s):  
Radar Imaging ◽  
Phase Coherence ◽  
Coherence Factor

Comparative investigation of coherence factor weighting methods for an annular array photoacoustic microscope

2021 ◽  
Author(s):  
Riku Suzuki ◽  
Ryo Shintate ◽  
Takuro Ishii ◽  
Yoshifumi Saijo
Keyword(s):  
Image Quality ◽  
Noise Suppression ◽  
Contrast Ratio ◽  
Comparative Investigation ◽  
Phase Coherence ◽  
Annular Array ◽  
Coherence Factor ◽  
Array Transducer ◽  
Weighting Methods

Abstract To achieve fine visualization of the peripheral microvascular networks, we have developed a photoacoustic (PA) microscope equipped with a four-channel annular array transducer. The quality of PA images processed with Delay-and-Sum (DAS) method is degraded by off-axis signals. Thus, to achieve higher image quality for the PA microscope, this study evaluated the efficacy of the five coherence factor weighting methods: coherence factor, sign coherence factor, phase coherence factor, circular coherence factor, and vector coherence factor. Using PA signals acquired from a 100 µm microtube and the skin microvessels, we generated PA images with DAS and one of the weighting methods, and quantitatively evaluated the image quality by calculating the sharpness, contrast ratio, and contrast-to-noise ratio. The results showed the phase coherence factor and the vector coherence factor methods were more effective to clearly visualize the microvascular structure, in terms of vessel sharpening and noise suppression performances, than the other methods.

The concept of partial coherence in optics

1951 ◽  
Vol 208 (1093) ◽  
pp. 263-277 ◽  
Keyword(s):  
Refractive Index ◽  
Statistical Analysis ◽  
Phase Coherence ◽  
Partial Coherence ◽  
Stellar Interferometer ◽  
Coherence Factor ◽  
Optical Images ◽  
New Treatment ◽  
Angular Radius ◽  
Made In

It is shown that a ‘phase-coherence factor’ may be defined in a manner which leads, without recourse to explicit statistical analysis, to the theorems established by van Cittert (1934) and Zernike (1938) for analogous factors. An invalid approximation made in their calculations of the phase-coherence factor for a plane illuminated directly by a source is corrected. The new treatment is applied to the theory of Young’s experiment, the stellar interferometer, and illumination in the microscope. The phase-coherence factor defined here enables a general theory of the formation of optical images to be formulated. Further, it is shown that the diameter of the area of coherence on a plane illuminated by a source of angular radius α is given by d ═ 0⋅16λ/N sin α , where N is the refractive index of the intervening medium.

scholarly journals Range Coherence Factor for Down Range Sidelobes Suppression in Radar Imaging Through Multilayered Dielectric Media

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 66910-66918 ◽  
Author(s):  
Qiang An ◽  
Ahmad Hoorfar ◽  
Wenji Zhang ◽  
Shiyong Li ◽  
Jianqi Wang
Keyword(s):  
Radar Imaging ◽  
Dielectric Media ◽  
Coherence Factor

scholarly journals 2-D Coherence Factor for Sidelobe and Ghost Suppressions in Radar Imaging

2020 ◽  
Vol 68 (2) ◽  
pp. 1204-1209 ◽  
Author(s):  
Shiyong Li ◽  
Moeness Amin ◽  
Qiang An ◽  
Guoqiang Zhao ◽  
Houjun Sun
Keyword(s):  
Radar Imaging ◽  
Coherence Factor

Sign-Coherence-Factor-Based Suppression for Grating Lobes in Through-Wall Radar Imaging

2016 ◽  
Vol 13 (11) ◽  
pp. 1681-1685 ◽  
Author(s):  
Jiangang Liu ◽  
Yong Jia ◽  
Lingjiang Kong ◽  
Xiaobo Yang ◽  
Qing Huo Liu
Keyword(s):  
Radar Imaging ◽  
Coherence Factor
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