Ji Jiang, Gao Peng-fei, Jia Nan-nan, Yang Rui, Guo Han-ming, Hu Qi, Zhuang Song-lin
Guang Pu Xue Yu Guang Pu Fen Xi. 2015 May;35(5):1445-9.
In order to smooth the spectra automatically and reliably, a spectral smoothing algorithm with adaptive multiscale window average (AWMA) is demonstrated. In this method, different positions of the spectra are smoothed by windows of different width, and the width of the windows will directly affect smoothing. The window with inappropriate width may cause excessive denoising (peak distortion or loss) or inadequate denoising (the flat region of the spectra still contains a lot of noise). So, how to get the right width of the window is the key of spectral smoothing. The algorithm optimized the width of windows by an iterative method, and verified whether the width is the best according to statistical Z-test. In order to increase the reliability of the algorithm, a comprehensive comparison of the thresholds of hypothesis according to simulation data of different SNR was performed. When the threshold is set to 1. 1, the denoising effect can be the best. In this work, the AMWA algorithm was tested by simulated spectra and real syectra, and it can automatically adapt to different spectral shape and different noise intensity. A comprehensive comparison of AMWA smoothing, Savitzky-Golay smoothing and moving average smoothing was performed in this paper, and the AMWA algorithm is better than the other two algorithms. Results show that the AMWA algorithm not only has better denoising effect, but also has higher accuracy and fidelity. This method has achieved great effect not only to simulated spectra but also to real spectra.
为了自动且可靠地平滑光谱,展示了一种具有自适应多尺度窗口平均(AWMA)的光谱平滑算法。在该方法中,光谱的不同位置由不同宽度的窗口进行平滑,窗口宽度会直接影响平滑效果。宽度不合适的窗口可能导致过度去噪(峰值失真或丢失)或去噪不足(光谱的平坦区域仍包含大量噪声)。所以,如何获得合适的窗口宽度是光谱平滑的关键。该算法通过迭代方法优化窗口宽度,并根据统计Z检验验证该宽度是否为最佳。为了提高算法的可靠性,根据不同信噪比的模拟数据对假设阈值进行了全面比较。当阈值设置为1.1时,去噪效果最佳。在这项工作中,AMWA算法通过模拟光谱和真实光谱进行了测试,它能自动适应不同的光谱形状和不同的噪声强度。本文对AMWA平滑、Savitzky-Golay平滑和移动平均平滑进行了全面比较,AMWA算法优于其他两种算法。结果表明,AMWA算法不仅具有更好的去噪效果,而且具有更高的准确性和保真度。该方法不仅对模拟光谱而且对真实光谱都取得了很好的效果。