针对大气痕量气体浓度的二维分布重建中的噪声问题,采用数值模拟的方法研究了噪声对差分吸收光谱断层扫描技术重构大气痕量气体空间分布 的影响,建立了噪声的模型,并研究了噪声对代数迭代重建算法(ART)和联合迭代重建算法(SIRT)两种重建算法的重建效果的影响。ART算法重建后,误 差Ea由0.1080降低到了0.0182; SIRT算法重建后,误差Ea由0.0476降低到了0.0102。结果表明,随着随机噪声的增加,重建图像变 态程度越来越严重。由重建相对误差指标可以看出,随着信噪比的增加,重建相对误差越来越小。因此,在外场重建实验中应该尽量避免噪声。

For the noise problem of two-dimensional concentration distribution reconstruction of trace gases in the atmosphere, the method of numerical simulation is adopted to study the influence of noise on the spatial distribution reconstruction of atmospheric trace gases by the differential absorption spectrum tomography. The noise model is established, the algebraic iterative reconstruction algorithm (ART) and simultaneous iterative reconstruction algorithm (SIRT) are researched, and the influence of noise on the reconstruction effects of the two kinds of reconstruction algorithm is also researched respectively. The error index Ea can be reduced from 0.1080 to 0.0182 by reconstruction of ART algorithm, and the error index Ea can be reduced from 0.0476 to 0.0102 by reconstruction of SIRT algorithm. The results show that with the increase of random noise, the abnormal degree of reconstruction image is more and more serious. From the relative error indicators of reconstruction, with the increase of signal-to-noise ratio, reconstruction of relative error is smaller and smaller. Therefore, noise should try to be avoided in field reconstruction experiment.