中阶梯光栅光谱仪二维谱图中， 信号光斑位置的提取精度直接影响光谱分析精度， 是中阶梯光栅光谱仪研制中的关键问题之一。 为保证中阶梯光栅光谱仪的高分辨率特征（其分辨率一般为几千以上， 本仪器光谱分辨率为15 000）， 信号光斑的位置提取误差应小于0.03 mm（小于2个像素）。 在分析中阶梯光栅光谱仪谱图特征的基础上， 提出了一种基于质心法的信号光斑位置提取算法， 即通过搜索信号光斑探测窗口进行光斑判读以及信号光斑质心计算， 实现了信号光斑位置的精确读取。 实验结果表明， 采用该算法可以有效地去除噪声光斑的干扰， 实现信号光斑位置的快速精确读取， 位置提取误差小于2个像素， 波长误差小于0.02 nm， 满足本仪器要求。

It is important for the echelle spectrograph to acquire the exact positions of the spots in the two-dimension spectra image, which directly influence the precision of spectral analysis. With the target of high resolution, which is 15 000 in the echelle spectrograph being discussed, the acquired positional error must be less than 0.03 mm-which equals 2 pixels. According to the characters of the two-dimensional spectra, a position-acquiring method for the signal spots based on the centroid computing algorithm was put forward. Applying this method, the signal spots were distinguished from the noise spots and their positions can be acquired accurately and swiftly, with the positional error less than 2 pixels and wavelength error 0.02 nm, which satisfy the requirements of the echelle spectrograph.