Application Of X-ray Imaging In The Three Dimensional Structure Characterization Of Porous Matrials

After the discovery of X-rays,because of its short wavelength and strong penetration advantages,a number of researchers begin to use X-ray technology in scientific research fields.With this method is non-destructive manner for many porous media,X-ray technology has a wide range of applications and development in industry and medical field.In recent years,the rapid development of synchrotron radiation techniques,normal desktop X-ray source is replaced by these high-strength,high-intensity X-ray source,coupled with high-speed,high-precision X-ray detector and an advanced control system,CT imaging technology has a qualitative leap.Shanghai Synchrotron Radiation Facility established a ?-CT line station which used Wiggler as a light source,have a high contrast ratio,ultra-high resolution,fast real-time and multi-mode imaging characteristics.This technology in the microelectronics industry,biomedical,energy and environmental sciences and has a wide range of applications.Based on this technological,there are two parts in the thesis:1.Building three-dimensional image analysis techniquesBased on the X-ray computer tomography and the characteristics of samples,established a series of three-dimensional image processing methods.We introduced several important algorithms of image preprocessing,through a series of technical studies including flat-field and dark-field correction,PPCT(propagation-based phase-contrast imaging)phase recovery,DEI(diffraction enhanced imaging)extraction,preprocessing,and slices reconstruction,etc.to get the best reconstruction of the original projection images.Described the three-dimensional image analysis techniques,including reading and writing raw data;based on 3D segmentation of different conditions(mainly introduces the gray threshold method and the local threshold segmentation method);and established the central axis of the model and obtained the pore throat structure.Introduced ?-CT analysis methods,including characterization of the three-dimensional structure,as well as quantitative measurement of some parameters(e.g.,volume,surface area,porosity,the length of throats and tortuosity).2.The application on the porous material(graphite,shale,etc.)by the CT technologyCombined X-ray computer tomography methods and the three-dimensional data characterization methods for different types of nuclear grade graphite material to get their three-dimensional pore structure and quantitative analysis of their structure parameters.This provided new methods and ideas for the study of the internal structure of the porous material and various simulations.The use of CT imaging technology,combined with image preprocessing,image segmentation,3D reconstruction and other image processing technology,complete characterization of shale samples,core obtain pore throat structure,fluid distribution information,to achieve rock pore structure and fluid visualization for research micro-scale simulation provides the foundation.This is also for the future of different scales rock pore throat structure,as well as the flow of pore fluid at different scales to provide direction.