Abstract：In the background of high zinc, when the concentration of trace polymetallic ions is simultaneously measured by spectroscopy, the energy radiation of the light source of the micro-spectrometer is not uneven, and different ions in the mixed solution can selectively absorb the ultraviolet-visible light at different bands. Therefore, too long integration time may lead to the saturation of spectral energy value, and if the integration time is insufficient, the signal-to-noise ratio of the spectral signal may be very low. The selection of integral time depends on the existing experience of researchers and the characteristics of the UV-Vis spectral signals of ions to be measured. In order to automatically select the integral time of micro-spectrometer, a high-quality UV-Vis spectral signal reconstruction algorithm based on the binary search is proposed to reconstruct the UV-Vis spectral signal with more distinct characteristics composed of different integral time. Firstly, the UV-Vis spectral energy reference solution is collected at the different integral time. Then the spectral energy signal target values of the reference solution are given, and the appropriate integral time sampling parameters are found at each wavelength point by using the binary search algorithm. Next, according to the characteristics of UV-Vis spectrum, the reconstruction accuracy index which is determined to represent the degree of proximity between the reconstructed spectral energy value and the target setting value and the feature saliency index which is used to indicate the degree of feature saliency before and after signal reconstruction are defined. Finally, the spectral signal with the highest reconstructed accuracy in the search interval is selected as the reconstructed information. The reconstructed information is used to reconstruct the UV-Vis spectral energy value of the solution to be measured. The reconstructed spectral absorbance signal of the solution to be measured is obtained at the end. The experimental results show that the proposed algorithm can quickly and automatically select the lintegral target time to reconstruct the UV-Vis spectrum signal, and to obtain high quality UV-Vis spectrum signal. The accuracy of signal reconstruction can reach 94.84%, and the reconstructed feature is improved significantly. At the same time, the absorbance signal of the reconstructed UV-Vis spectral signal is enhanced. Compared with the UV-Vis spectral signal before reconstruction the signal-to-noise ratio of the spectral signal after reconstruction is greatly improved, and the problem of choosing the parameters of integral time based on the subjective judgement of researchers is avoided. It provides high quality model data for detecting the concentration information of various trace metal ions.
Key words：Micro-spectrometer; Signal reconstruction; Binary search; Integration time; Spectral energy value
[1] Wang Guowei, Yang Chunhua, Li Yonggang, et al. Chemometrics and Intelligent Laboratory Systems, 2016, 151(15): 61.
[2] Karami C, Alizadeh A, Taher M A, et al. Journal of Applied Spectroscopy, 2016, 83(4): 687.
[3] Ren Xiaodong, Lei Wuhu, Wang Yong. Optic, 2019, 185: 497.
[4] Chen Xuan. Computers & Electrical Engineering, 2018, 69: 865.
[5] DUAN Li-guo, ZHU Li, LI Xiao-wei, et al(段利国，朱 丽，李晓伟，等). Journal of Beijing University of Posts and Telecommunications(北京邮电大学学报), 2018, 41(2): 119.
[6] ZHANG Jiang-tao, XIA Ke-wen, ZHOU Qiao, et al(张江涛, 夏克文, 周 巧, 等). Science Technology and Engineering(科学技术与工程), 2018, 18(9): 278.
[7] Qi R, Yang D, Zhang Y, et al. Signal Processing, 2018, 153: 34.
[8] CHEN Shan-xiong, HE Zhong-shi, XIONG Hai-ling, et al(陈善雄，何中市，熊海灵，等). Chinese Journal of Computers(计算机学报), 2015, 38(3): 614.
[9] Yao S, Guan Q, Wang S, et al. EURASIP Journal on Wireless Communications and Networking, 2018, 2018(1): 78.
[10] WANG Xin, HE Hao, FAN Xian-guang, et al(王 昕，何 浩，范贤光，等). Spectroscopy and Spectral Analysis(光谱学与光谱分析)，2018, 38(1): 93.
