Acta Photonica Sinica, Volume. 54, Issue 3, 0312003(2025)
Research on Improving the Frequency Shift Characteristics of Rotational Velocity Measurement Based on Truncated Weighted Wirtinger Flow Algorithm
In the remote detection of the rotational velocity of a target, the vortex beam is easily affected by the random atmospheric turbulence, which causes the phase distortion of the beam and the dispersion of OAM spectrum, resulting in the deterioration of the performance of rotational velocity measurement. Since Wirtinger flow algorithm was proposed, its remarkable feature is that it can complete iterative convergence without any prior information and only one input, without falling into local optimal solutions. Relevant studies have theoretically shown that Wirtinger Flow algorithm has the ability of high precision and absolute convergence to the global optimal solution. The current research has improved the performance of the algorithm by enhancing the traditional WF algorithm. However, the analysis of improving the rotational velocity measurement metrics through compensating the beam distortion in complex environments is still insufficient.To solve this problem, this work enhances the traditional WF algorithm by improving the initialization and gradient descent rules, and proposes Truncated Weighted Wirtinger Flow (TWWF) algorithm. In this algorithm, the median value of the sample is introduced into the truncation rule in the initialization stage to make the initial estimation closer to the global optimal. The weight adjustment strategy of the weighted gradient descent algorithm is used to calculate the weight coefficient according to the results of adjacent iterations, and the distorted vortex beam is compensated to improve the optical field and the rotating Doppler frequency shift characteristics.Firstly, a vortex light field recovery and rotation velocimeter performance improvement system based on TWWF algorithm is designed. The input is simplified into one path. The probe beam then passes through the coded aperture of a programmable LCD screen, simulating a coded diffraction pattern, and then the CCD measures the light intensity for algorithm calculation, and finally the generated compensated phase screen is loaded on the spatial light modulator. The results show that when the atmospheric turbulence intensity
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Hongyang WANG, Zijing ZHANG, Hao LIU, Xinran LYU, Jiayu SONG, Chengshuai CUI, Yuan ZHAO. Research on Improving the Frequency Shift Characteristics of Rotational Velocity Measurement Based on Truncated Weighted Wirtinger Flow Algorithm[J]. Acta Photonica Sinica, 2025, 54(3): 0312003
Category: Instrumentation, Measurement and Metrology
Received: Aug. 26, 2024
Accepted: Nov. 11, 2024
Published Online: Apr. 22, 2025
The Author Email: Zijing ZHANG (zhangzijing@hit.edu.cn)