Research On Coal And Gangue Smart Sorting Control System Based On X-Ray Image

At present, the main traditional coal preparation methods are based on the physical principle, like wet cleaning method and dry method. Dense medium coal method and jigging coal method belong to wet method while y-ray coal method belongs to dry method. When these methods are used, the problems of resource waste, environment pollution, high cost and unsafety are coming. With these problems, this paper presents a new method of identifying coal and gangue which is based on the X ray image, and gives a research on the sorting control system. There are advantages, such as simple operation, low cost, less resource waste and high recognition accuracy when the method based on X ray image is used.The sorting method in this paper is based on the principle that density and absorption coefficient to X ray of coal and gangue are different while the attenuation degree is also different. When the X ray produced by the X ray resource transmits to coal and gangue on the belt conveyor, the detectors and data acquisition board collect and transform the X ray signal after attenuation while the X images are collected. Then the X images of coal and gangue will be processed and recognized by the host computer.The sorting control system is made up of detection part, recognition part and sorting part. The detection part realizes the connection of queuing machine, belt conveyor and X-Ray resource. The recognition part realizes the connection and control among detectors, data acquisition board and the host computer while the X images are collected in the part. The sorting part realizes the control and connection between the host computer and high-pressure air valve, which aims to hit gangue.In the research of recognition algorithm, the X images of coal and gangue are pretreated by median filter. Then the target edge is extracted by Roberts operator, which will be shined upon the original X image. And the X images are binaried by Ostu operation. After that procedure the target height can be computed indirectly. Meanwhile the gray value of pixel peak which belongs to coal and gangue in original X images can be collected by image segmentation and histogram analysis. After doing a series of experiments, we collected gray value of pixel peak and height of coal and gangue. According to the relationship between the gray value and height, the condition of recognition and threshold are confirmed. The recognition of coal and gangue which are different size is realized.The system in the paper uses the sorting method which is based on the X ray images. With the analysis of target’s gray value and height, coal and gangue of different size are recognized and sorted. The effect on recognition accuracy caused by target’s size is eliminated and the recognition accuracy is highly raised. Meanwhile the system is operated easily, needs less equipments and cuts down the cost.