线阵CCD紫外光谱仪的波长定标研究

Research on Wavelength Calibration of Linear-CCD UV Spectrometer

波长定标的精度是衡量光谱仪的重要指标之一。鉴于其重要性,研究了线阵电荷耦合器件(Charge-Coupled Device,CCD)紫外光谱仪的波长定标,并完整地给出了一种波长定标方法(包括噪声扣除、谱峰定位和波长拟合三部分)。针对暗噪声影响光谱信号的问题,提出了一种利用非曝光像元扣除暗噪声的方法;针对谱峰漂移的问题,提出了一种基于权重窄窗差分的谱峰定位方法;针对单一光源特征谱线数量不足的问题,提出了一种多波段波长拟合方法。实验结果表明,本文方法的波长定标精度在0.6nm之内,关键波长点上的定标精度在0.01 nm之内,具有定标精度高、复杂度低等优点,因此可用于紫外光谱仪的波长定标。

The accuracy of wavelength calibration is one of the important specifications for measuring a spectrometer. Because of its importance, the wavelength calibration of a Charge Coupled Device （CCD） array UV spectrometer is studied. A new wavelength calibration method containing noise deduction, spectrum peak location and wavelength fitting is given. To reduce the influence of dark noise on spectral signals, a method for deducting dark noise by using non-exposure pixels is proposed. To solve the problem of spectrum-peak drift, a spectrum-peak location method based on weight narrow-window difference is proposed. For the lacking of spectrum line of a single light source, a multiband wavelength fitting method is proposed. The experimental results show that the proposed method has its wavelength calibration accuracy less than 0.6 nm. Its calibration accuracy at key wavelength points is less than 0.01 nm. Because of the advantages of high calibration accuracy and low complexity etc, it can be used for the wavelength calibration of UV spectrometers.