Research And Implementation Of Fusion Of X-ray Imaging Image In Tube And Tube Sheet Weld Testing

Tube-tube sheet joint is the main link of the tubular heat exchanger and the reactor.It is an important part to ensure the stable operation of the heat exchanger and no leakage.The safety cannot be ignored.Small defects such as bubbles,slag inclusions and cracks in the welded joints of the pipe and tube sheets may cause quality problems such as poor sealing and leakage at the joints,resulting in safety hazards.Before the heat exchanger is put into use,it is necessary to perform internal defect detection on the welded joint.In the industry,the X-ray inspection technology of the pipe and tube weld is usually used in the industry,and the X-ray inspection technology can obtain the X-ray transillumination image of the internal information of the welded joint.The process of collecting weld image by tube-tube X-ray inspection technology is mainly to image the detected object by X-ray irradiation.Due to the influence of detector specifications,a CMOS detector cannot collect all the images of the weld area.Eight equal-sized detectors are spliced together to capture images.The splicing of the detector results in a gap in the acquired X-ray image.This image cannot contain all the information about the weld area.Therefore,in order to obtain a complete X-ray imaging image without gaps,the X-ray imaging image fusion technology in the tube and tube weld inspection was studied.This topic requires fixed ray source and detected object,rotating detector to collect multiple images,multiple images of different transillumination angles for the same object,and research image fusion technology.The main research contents include:(1)Simulate multiple image superpositions with constant center points to cover the effect of all the gaps,and calculate the number and angle of rotations the detector needs to rotate;(2)Two different methods are used to extract linear gap images,which are based on geometric positioning and hough transform respectively,to obtain the linear gap images and their spatial positions.The linear gap extraction based on hough transform needs to preprocess the acquired image.(3)Image registration technology is used to process the image,and the improved weighted average gray image fusion algorithm is used to fuse it with the source image,so as to realize the fusion of multiple ray images at the same position.(4)Based on the fusion method of local gray value averaging,the fusion algorithm used in the paper is evaluated by subjective observation of the merged image and contrasting fusion image with objective parameters.The algorithm of this paper is implemented on the MATLAB 2015b platform.The platform window and the wavelet toolbox are used for image fusion,and the parameter values embodying the image effect are compared.The results show that for the specific tube-tube plate ray digital imaging detection system,the multi-image fusion technology studied in this paper can effectively solve the problem of blind spot detection and missed detection caused by detector splicing.