基于深度相机与双能X射线双模态数据融合的煤矸识别和密度预测

Coal-gangue recognition and density prediction via dual-modal data fusion of depth camera and DE-XRT

  • 摘要: 为削弱DE-XRT(Dual Energy X-Ray Transmission)系统的厚度效应,实现宽厚度范围内煤矸的精准识别和密度预测,深入总结了DE-XRT的成像原理,并在数据层面上融合了深度相机和DE-XRT。依据煤矸目标尺寸和区域相似性,针对性分区DE-XRT图像和厚度图像,并通过将单像素扩展为多像素集合的方式,实现2类信息更加准确、高效地利用。进一步地,以各分区对应的X射线信息与厚度信息作为依据,利用射线能量衰减公式计算融合信息,并将各分区的融合信息统计为分块矩阵。通过分块矩阵和DE-XRT图像提取多维异构特征,结合Relief特征选择算法及GA(Genetic Algorithm)优化后的SVM(Support Vector Machine)分类器构建了一种适应性强的预识别模型。此外,通过对分块矩阵的变换计算和对大规模样本的统计分析,获取了各密度级煤的模糊区间,并构建了一种基于模糊区间的密度预测模型。该模型充分考虑了使用单一公式计算不同密度级煤的影响,通过建立模糊区间将煤密度的预测问题拆分成多个密度级的预测问题。同时,以待预测目标与区间下限的偏离度表征其与下限密度级的接近程度。试验结果表明:在处理煤密度范围为1.3~1.8 g/cm3、矸石密度范围为≥1.8 g/cm3、平均厚度范围为5~100 mm的数据集时,预识别模型的精确率Pre和F1分别为97.522%和0.962。相比现有X射线算法、灰度纹理法及深度学习算法,Pre、F1分别至少提高6.433%和2.888%。密度预测模型的平均误差不超过5.882%,且46.993%的目标预测误差小于4%,93.233%的目标误差小于10%。所提模型可有效减少厚度效应对分选系统的影响,提高宽厚度范围内煤矸的识别和密度预测精度,为智能光电煤矸分选技术研发提供了理论依据。

     

    Abstract: To mitigate the thickness effect of the Dual Energy X-Ray Transmission (DE-XRT) system and achieve accurate identification and density prediction of coal and gangue within a wide thickness range, this study thoroughly summarizes the imaging principle of DE-XRT and fuses depth cameras with DE-XRT at the data level. Based on the size of coal gangue and regional similarity, the DE-XRT images and thickness images were partitioned. By expanding single pixels into multi-pixel sets, the two types of information were utilized more accurately and efficiently. Furthermore, using the X-ray and thickness information of each partition as the basis, fused information is calculated via the X-ray energy attenuation formula, and then aggregated into block matrices. Multidimensional heterogeneous features were extracted from these block matrices and the DE-XRT images. A robust pre-identification model was then constructed by combining the Relief feature selection algorithm with a Support Vector Machine (SVM) classifier optimized by a GA (Genetic Algorithm). Additionally, via transformation calculations of block matrices and statistical analysis of large-scale samples, the fuzzy intervals of coal at various density levels were determined, and a density prediction model based on these intervals was developed. This model considers the impact of using a single formula to calculate coals of different density grades. By establishing fuzzy intervals, the problem of coal density prediction is decomposed into multiple density-grade prediction problems. Meanwhile, the degree of deviation between the target to be predicted and the interval lower limit is used to characterize its proximity to the lower-limit density grade. Experimental results demonstrated that, on a dataset with coal densities ranging from 1.3 to 1.8 g/cm3, gangue densities greater than 1.8 g/cm3, and average thicknesses spanning 5 to 100 mm, the pre-identification model achieved an Pre of 97.522% and an F1 of 0.962. Compared with existing X-ray algorithms, grayscale texture methods, and deep learning algorithms, the Pre and F1 were improved by at least 6.433% and 2.888%, respectively. The density prediction model exhibited a mean error not exceeding 5.882%. Specifically, 46.993 of targets had prediction errors below 4%, and 93.233% had errors below 10%. The proposed models effectively reduce the impact of the thickness effect on the sorting system, enhance the accuracy of coal-gangue identification and density prediction across a broad thickness range, and provide a theoretical foundation for developing intelligent photoelectric coal-gangue sorting technologies.

     

/

返回文章
返回