Study On The Method Of Second Generation Industrial Ct Scan Image Reconstruction

X-ray testing technology is one of the important non-destructive testing method, widely used in many fields such as industry,safety,material,biology and so on. Digital Radiography(DR) and Computer Tomography(CT) are two kinds of commonly used X-ray testing method.We choose and research the topic according to the imaging technological problems that are encountered in industrial CT/DR equipment development.The major work of this paper is as follows.Aimed to solve the geometric artifacts in CT image of second generation CT scanning mode,we proposed a new method for CT image reconstruction from such scanning mode.The so-called second generation scanning mode is a data scanning configuration involved in the translation and rotation of the CT turntable.The conventional reconstruction method for CT image reconstruction from the scanning data needs first to rebinning the projection data to parallel beam projection data,and then reconstruct image by FBP(filtration backprojection) algorithm for parallel beam projection data or iteration algorithm.Both of them need to know some geometric parameters of CT scanning mode.The parameters can not be measured directly,and the error in estimation value often conducts geometric artifacts in CT image.We introduce a set of new parameters in the new image reconstruction method,which can be estimated from the projection data of a thin tungsten filament scanned in second generation scanning mode.Our method is simple and robust,compared with the common parameter estimation method which is involved to solve nonlinear equation.Aimed to solve the problem that the details in DR image are hardly distinguished, we propose an image enhancement method.DR image is overlapping in itself and the data distribute on a wide range.As a result,some interested detail information can not be distinguished when the data is uniformly qualified into 256 gray levels.Our method can highlight some interested information of DR image in detail and improve the contrast effectively for target region.