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对彩虹测粒技术的参数反演进行研究,提出了一种新的参数反演模型和算法。新算法基于经验模态分解(EMD)的去噪技术,能在较低信噪比(SNR)条件下有效滤除噪声干扰,并能有效避免信号损失和信号的空间偏移;提出了一种特征点提取技术,能有效压缩反演计算量;提出了基于电磁散射中德拜(Debye)理论的反演最优点搜索算法,能较精确迅速地找到反演最优点;提出了基于米氏(Mie)理论的参数精确反演,大大提高了反演的准确性,降低了折射率的反演误差,扩大了算法适用范围。为验证算法精度,模拟分析了直径范围35～900μm,折射率范围1.32～1.34的水液滴在不同噪声环境下的参数反演。结果表明,在信噪比高于40 dB的情况下,直径反演结果可精确到1μm,折射率反演结果可精确到小数点后三位;当信噪比降至5 dB时,直径反演最大误差小于10%,折射率反演最大误差小于0.1%。
The parameter inversion of rainbow particle measurement technique is studied, and a new parameter inversion model and algorithm is proposed. The new algorithm based on empirical mode decomposition (EMD) denoising technology can effectively filter out noise interference at lower signal-to-noise ratio (SNR) and effectively avoid signal loss and signal spatial offset. A new algorithm The feature point extraction technique can effectively compress the calculation of inversion. A search algorithm based on the Debye theory of electromagnetic scattering is proposed, which can find the optimal point of inversion more accurately and quickly. Mie) theory, which can greatly improve the accuracy of inversion and reduce the error of inversion of refractive index, and enlarge the scope of application of the algorithm. In order to verify the accuracy of the algorithm, the parameter inversion of water droplet in the range of 35 ~ 900μm in diameter and refractive index range of 1.32 ~ 1.34 was simulated and analyzed in different noises. The results show that when the signal to noise ratio is higher than 40 dB, the diameter inversion result can be accurate to 1 μm and the refractive index inversion result can be accurate to the third decimal place. When the signal to noise ratio is reduced to 5 dB, the diameter inversion The maximum error is less than 10%, and the maximum error of refractive index inversion is less than 0.1%.