| Rock blasting fragmentation analysis is very important in a mining indutry. Reasonable blasting parameter can reduce the costs of mining and lessen the subsequent workload, so that the overall efficiency in a mining industry can be greatly improved. Usually, the commonly used methods of fragmentation analysis are sieving, statistics on the rate of big block etc. All these methods have more or less limitations.Based on digital image processing technology and the fractal theory, this paper proposes an image segmentation method based on wavelet resolution merge and watershed segmentation algorithm, to make sure that the segmented image is proper for rock blasting fragmentation analysis.Firstly, Photograph scheme is determined according to the site condition, and the digital images information is taken. Photoshop 5 is used to geometrically correct the original digital images. For the original digital images, there are often two kinds of problems for rock blasting fragmentation analysis. One is unevenness of gray level in the image, and the other is the high level of noise in the image. For these two kinds of questionable images, different image processing methods are used to process the images to make sure that the processed images are suitable for rock fragmentation analysis. For uneven of gray level, brightness reversal and image enhancement techniques are used first, then wavelet resolution merge technique is used. For the image contained high level of noise, the noise is reduced first, and the histogram modification method is used to enhance the image. After that wavelet resolution merge technique is also used for the image with high level of noise. After the digital processing procedure, using either of the methods, the improved watershed segmentation algorithm is used to further process the digital images. The improved watershed segmentation method is proposed, based on correctly marking the objects on the foreground and background respectively, to properly segment the blocks in the digital images. Finally, the statistics are carried out on the digitally processed images by two statistical methods for blasting fragmentation analysis. In one method, the size of the rock block is calculated by the actual size and maximum string length from surface of the block in the digital image. In the other mothed, the size of the rock block is comprehensively appromated by three paramethers related with the size of a block, the area, length of a segment crossing the block and the volume.It has been found that the proposed digital processing techniques are suitable for the rock fragmentation analysis in a digital image. It can be used for quick statistic on distribution of rock blasting fragmentation. It less affects the product work. |
