The Research Of Coal Flotation Froth Image Feature Extraction Method

The main basis for coal flotation is the differences in physical and chemical properties of coal particles and gangue particles surface. Hydrophobic coal particles with better flotability rise to the surface to form the froth layer, while hydrophilic gangue particles with poor flotability remain in the coal slurry become flotation tailing by adding chemicals. The number of coal particles adhered in the bubble surface can be characterized by the foam visual information, so the flotation state can be judged by the surface characteristics of flotation foam layer. Currently, flotation foam under different state is saved in the form of image, flotation froth images are continuous intaked by Industrial CCD camera, the flotation states are identified by foam image’s characteristics. In order to extract the required parameters, a series of pretreatment should be done in the process of feature extraction of flotation froth image.In this paper, various image processing approaches for bubble images which have a large of noise, low contrast, bubble shadow and so on are researched in the image feature extraction process, some improved algorithms are imposed after analyzing and comparing these methods, and the accuracy of the proposed method is verified by simulation. The paper mainly studied the following aspects:Fistly, the image denoising method is researched, The area reconstruction by opening and closing filter method and the Gaussian filtering method are improved, it proposed two denoising methods-n algorithm combining with area reconstruction by opening and closing filter and alternating sequential filter and an adaptive Gaussian filtering method, and the scope of application of each method is analysed by comparing the two methods.Secondly, the image segmentation method is researched, it proposed an improved watershed segmentation method based on the mark superimposed by combining a marker watershed segmentation based on Gaussian filtering and a watershed segmentation method based on the FCM. It verifies the effectiveness of this method after simulation experiments. Besides, a watershed segmentation method by extracting the markers from low frequency components of the gradients and a watershed segmentation method based on morphological pre-processing and markers extraction were compared with this improved method, it further confirmed the accuracy of this method.Finally, the features of flotation froth images are extracted, which mainly include texture characteristics, size characteristics, foam stability and foam carrying capacity, The validity of the four characteristic quantities is verified by laboratory flotation tests.