Research On The Imaging System Of Wooden Structure Ancient Pillars Based On CT Technology

With the social progress and the development of science and technology,nondestructive testing technology has developed rapidly,which has been widely used in industry,medicine and other fields.However,for the non-destructive testing of wood and wood structure building components,the existing testing equipment has certain limitations.It can not achieve completely non-destructive testing,and the testing accuracy also needs to be improved.CT detection can achieve complete non-destructive testing and provide high-quality,high-precision detection results.At present,the existing industrial CT and medical CT are expensive and can not be moved at will.The equipment is hard to operate and it requires high technical operation skills,to some extent,which limit the development and application of CT technology in the field of wood.Therefore,on the premise of ensuring the accuracy and quality of CT detection,it is of great significance for the development and promotion of CT technology to improve the flexibility of CT detection equipment and the controlability of upper computer software.In this paper,the imaging system of ancient wooden structure column based on CT technology is designed.The system can control X-ray transmitter,receiver and carriage,and has the functions of projection data acquisition,data processing,image reconstruction and three-dimensional image.The platform can move freely,which can not only provide high-quality fault reconstruction image,but also meet the needs of on-site detection.The system provides high-efficiency and high-quality CT nondestructive testing services for the protection of ancient wooden structure columns and the detection of precious wood specimens.The main research work of this paper is as follows:1.Overall design of the system.According to the current situation of non-destructive testing and CT technology of wood structure building at home and abroad,this paper analyzes the needs of building real-time imaging system,and carries out the overall design of the system.The research includes hardware design and upper computer software design.The hardware design of the system includes the construction of the control platform,the selection of X-ray transmitter and receiver,the construction of PLC control system and the design of protective measures.According to the functional requirements of the upper computer software,the upper computer software design needs to realize the X-ray transmitter and receiver control,carriage control,dataacquisition,image reconstruction and three-dimensional image display functions,and design the upper computer software framework.2.Design and implementation of upper computer software.Based on the MFC framework of visual studio,the system upper computer interface and software functions are designed and implemented.The specific functions include equipment control,image acquisition,image reconstruction and three-dimensional image display.3.CT projection data processing method.According to the basic principle of CT image reconstruction and related research content,this paper improves the CT projection data processing method,effectively improving the quality of CT reconstruction image.There are various factors affecting data acquisition,including equipment aging,detection point damage,light,mechanical error and other factors.In order to reduce the influence of these factors on the collected data,in the process of obtaining the original projection data to image reconstruction,the original projection data is modified by four processing steps: bad point data correction,"darkroom" processing,effective data interception and rotation dynamic error correction.After data processing,the imaging system studied in this paper can effectively remove the defects of the reconstructed image,such as ring artifacts,black rings,gray vertical lines with different depths.4.Overall test of the system.In order to study the stability of the system as well as the requirement and influence of the system on the computer performance,the designed CT imaging system was tested in black box.After testing,the system runs stably under Windows 7 platform and meets the needs of project testing.In this project,the CT imaging system developed for the nondestructive testing of ancient building columns can accurately present high-quality wood fault reconstruction images,and has designed a high manipulation and powerful upper computer interface,which can display three-dimensional fault images with clear outline and obvious internal structure features,providing a more accurate,intuitive and convenient detection system for the protection and repair of ancient building columns,which is of great significance for nondestructive testing of ancient building columns and precious living trees.