Research On Algebra Reconstruction Technique Of CT Image

CT (Computerized Tomography), is an imaging technique which obtain the objectcross-sectional information through the measurements of different angles ray projection. CTenhances the human ability of observing the internal structure of the object. CT has beenwidely applied in various fields, such as medical diagnostics, industrial inspection, securitychecks, radio astronomy. Especially in medical diagnosis, it provides a good way for diseasediagnosis without damage.CT image reconstruction algorithms can be roughly divided into the analyticreconstruction algorithm and the iterative reconstruction algorithm. One of the analyticreconstruction algorithm, the filtered back projection method is simple and fast convergence.It is currently the most commonly used algorithm of the CT image reconstruction algorithms.However, in the case of incomplete projection data, the image reconstruction result throughthe filtered back projection method is usually bad, and the image reconstruction result throughthe iterative reconstruction algorithm is still good. In the actual medical and industrialapplications, sometimes people cann’t get the complete projection data because of theenvironment to be detected, the cost and limited time. With the rapid development ofcomputer technology, the problem of slow convergence of the iterative reconstructionalgorithm can be solved. Therefore, the iterative reconstruction algorithm become moreimportant. The algebraic reconstruction technique, ART algorithm, is the most typical andmost basic kind of the iterative reconstruction algorithm. This paper studies some factors ofthe ART algorithm and make the simulation and analysis. In addition, it proposes a method toarrange the order of projection of ART algorithm. The method is based on minimum relevantinformation.This paper can be divided into three parts:Firstly, it describes the background and significance of CT image reconstruction. Itdescribes the history, current situation and development trend of the algebraic reconstructiontechnique. It describes the basic principle of CT image reconstruction, including the imagingsystem, imaging mathematics, imaging principle.It introduces the classification ofreconstruction algorithms and details a variety of iterative reconstruction algorithms. Secondly, it studies some factors of ART algorithm and make some simulation usingmatlab. The factors include the initial value selected, considering the impact of priorknowledge, the relaxation factor selected, arranging the order of projection.Finally, it proposes a method to arrange the order of projection of ART algorithm. Themethod is based on minimum relevant information. It uses matlab to make some simulation ofsequential mode, random mode and the new method which it proposes.It compares thesethree methods.