Study on Hyperspectral Inversion of Rare-Dispersed Element Cadmium Content in Lead-Zinc Ores
LAI Si-han1, LIU Yan-song1, 2, 3*, LI Cheng-lin1, WANG Di1, HE Xing-hui1, LIU Qi1, SHEN Qian4
1. Key Laboratory of Tectonic Controlled Mineralization and Oil Reservoir of Ministry of Natural Resources（Chengdu University of Technology), Chengdu 610059, China
2. Chengdu Center, China Geological Survey, Chengdu 610081, China
3. China University of Geosciences, Beijing, Beijing 100083, China
4. Sichuan Sumhope Spatial Technology Co., Ltd., Chengdu 610094, China
Abstract：Rare-dispersed element mineral resources are the key mineral resource in the national economy. The information extraction of content is the basis for potential evaluation and target optimization of mineral resources, but the existing analysis technology of rare-dispersed elements cannot meet the needs of rapid detection and potential evaluation. The analysis technology of rare-dispersed element based on Hyperspectral is a way to solve this problem. Therefore, the Sinongduo-Zexue ore concentration area in Tibet is the study area, and the hyperspectral inversion method and inversion model about the content of rare-dispersed element cadmium (Cd) in lead zinc ore are studied. ASD FieldSpec 3 spectrometer and supporting software are used for spectral data acquisition and pretreatment. Based on spectral feature analysis, multi-type spectral transformations such as first derivative (FD), second derivative (SD), logarithm of the reciprocal (AT), first derivative of logarithm of the reciprocal (AFD), second derivative of logarithm of the reciprocal (ASD) are carried out, the characteristic bands selected by Pearson correlation coefficient (r) are used for the modeling and inversion of random forest (RF), artificial neural network (ANN), support vector machine (SVM), the effect and prediction accuracy of content inversion models are evaluated by the coefficient of determination (R2), and root mean square error (RMSE). The results show that the spectral reflectance of the sample is concentrated in the range of 40%~60%, and the absorption peaks are formed at 1 420, 1 920 and 2 200 nm. The characteristic bands cover the visible and near-infrared bands, and 771~2 051 nm is the optimal range of the characteristic band. SD is the best spectral data dimensionality reduction method, which has selected 15 characteristic bands. ASD has selected 8 characteristic bands, and AFD has selected 2 characteristic bands. FD and AT did not select the characteristic band. In the characteristic band inversion of SD selection, the SD-ANN model (R2=0.884, RMSE=2.679) has the best prediction effect of cadmium content, followed by the SD-SVM model (R2=0.830>0.8, RMSE=1.382), SD-RF model has the worst prediction effect (R2=0.505<0.6). In the characteristic band inversion of ASD selection, the best prediction of cadmium content is the ASD-SVM model (R2=0.857, RMSE=2.198), followed by the ASD-ANN model (R2=0.846, RMSE=2.625). The hyperspectral inversion effect of cadmium (Cd) content is: SD-ANN>ASD-SVM>ASD-ANN>SD-SVM>ASD-RF>SD-RF. The study summarizes the hyperspectral characteristics of cadmium, establishes the hyperspectral inversion method and model of cadmium content, provides a reference for hyperspectral inversion, nondestructive testing and rapid analysis of rare-dispersed elements such as cadmium, and provides theoretical support for the potential evaluation and target optimization of rare-dispersed element mineral resources in the high-altitude exploration area.
Key words：Rare-dispersed element; Cadmium content analysis; Hyperspectral inversion; Visible and near infrared spectroscopy; Lead zinc ore
赖思翰，刘严松，李成林，王 地，何星慧，刘 琦，沈 茜. 铅锌矿石稀散元素镉含量的高光谱反演研究[J]. 光谱学与光谱分析, 2023, 43(04): 1275-1281.
LAI Si-han, LIU Yan-song, LI Cheng-lin, WANG Di, HE Xing-hui, LIU Qi, SHEN Qian. Study on Hyperspectral Inversion of Rare-Dispersed Element Cadmium Content in Lead-Zinc Ores. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2023, 43(04): 1275-1281.
