In Laser self-mixing interferometry (SMI), phase unwrapping methods are widely utilized for high-resolution displacement measurements. In this work, a Time-frequency signal processing (TFSP) method for SMI based displacement retrieval is analyzed. Its limitations are identified, and an improved and more robust version of TFSP is proposed for enhanced resolution and better sensing in a non-ideal situation. By rectifying the phase inversion errors present in TFSP, the proposed work can process the laser phase more efficiently than TFSP. Furthermore, the proposed work can also accommodate significant amplitude fading of laser feedback signal by applying the Hilbert transform based signal processing technique, making it robust than TFSP.The proposed work demonstrates that the Hilbert processing technique and improved phase estimation shows approximately 90% improvement over the TFSP method for simulated SMI signals from different feedback regimes and amplitude variations. Additionally, experimental results for various C values indicate an average improvement of around 29% compared to TFSP.Lastly, FPGA based emulation of ITFSP is performed for embedded sensing applications. While operating at 180 MHz, the ITFSP can measure a maximum target velocity of 4.5 m/s.The development of such a robust and high-resolution method is a critical step towards a compact laser-based sensor for high-resolution applications, even for non-cooperative targets and rough environments causing laser light fading.

在激光自混合干涉测量 (SMI) 中，相位展开方法被广泛用于高分辨率位移测量。在这项工作中，分析了基于 SMI 的位移检索的时频信号处理 (TFSP) 方法。确定了它的局限性，并提出了一种改进的、更健壮的 TFSP 版本，以在非理想情况下提高分辨率和更好的感知。通过纠正 TFSP 中存在的倒相误差，所提出的工作可以比 TFSP 更有效地处理激光相位。此外，所提出的工作还可以通过应用基于希尔伯特变换的信号处理技术来适应激光反馈信号的显着幅度衰减，使其比 TFSP 更稳健。所提出的工作表明，对于来自不同反馈机制和幅度变化的模拟 SMI 信号，希尔伯特处理技术和改进的相位估计比 TFSP 方法有大约 90% 的改进。此外，各种实验结果C值表明与 TFSP 相比平均提高了约 29%。最后，针对嵌入式传感应用执行基于 FPGA 的 ITFSP 仿真。在 180 MHz 下运行时，ITFSP 可以测量 4.5 m/s 的最大目标速度。 开发这种稳健且高分辨率的方法是朝着用于高分辨率应用的紧凑型激光传感器迈出的关键一步，即使对于非合作目标和恶劣环境导致激光衰减。