Study On Measurement Of Abnormity Parts And3D Modeling And RP (Rapid Prototype) Based On Computed Tomography

In industrial production,people often need to know the area,perimeter,curved areaand volume of the complex closed cavity and to rebuild the complex closed cavitymodel is very necessary,while the conventional methods are difficult to achieve thereconstruction of complex closed cavity and geometrical dimension measurement.without damage.CT can display the internal structure of the detected object in theform of the two-dimensional tomographic image with clearly,accurately andvisually.which can detect any complex shape of the closed cavity.CT has been widelyused in the field of medical, aerospace, machinery etc.Base on CT technology and CTdetection data,in the paper the reconstruction method of complex closed cavity andgeometric parameters measurement is studied.The main work of the paper are as follows:1．A geometric measurement method based on robust statistics and regionscalable fitting has been studied.In this method, robust statistics and region-scalablefitting model is used to extract ordered chain of target edge coordinates. And then,Green theorem and Euclidean distance formula are applied to compute the area andperimeter of target region. At the step of extracting target edge, the robust statisticaltheory is put into region-scalable fitting model to improve the measurement accuracy.In computing area and perimeter of target region, the Lagrange interpolation methodis used to interpolate the orderly coordinates to get smooth target edge, which furtherimproves the measurement accuracy. Using the presented measuring method in thispaper, measuring complex enclosed inner cavity in industry is realized.Compared withthe improved C-V model,the presented measuring method in this paper has higheraccuracy. And, it can measured image with noise accurately. 2．A geometric measure method with robust statistics and region-scalable fittingmodel based on CT(Computed Tomography) has been studied.In order to measurecomplex enclosed inner cavity,A geometric measure method with robust statistics andregion-scalable fitting model based on CT is presented to measure volume and surfacearea of enclosed inner cavity.The main content of this method are as follows:thetwo-dimensional robust statistics and region-scalable fitting model was used to extractthe target edge of images.Then,the orderly chain coordinates is got and the Lagrangeinterpolation method is used to interpolate the orderly coordinates,which furtherimproves the accuracy of measure. And then,Green theorem and Euclidean distanceformula are applied to compute the area and perimeter of image.At last, According tothe platform formulation,the internal volume and surface area are measured.According to the experimental results,compared to the C-V measure methods,thepresented measure method has better precision.3．The three-dimensional reconstruction of complex closed lumen volume basedon Computed Tomography has been studied.A method is presented by creating a STLmodel from CT slices data of natural bone and then forming artificial bone with laserrapid prototyping. Edge extraction is used to get the target edge of natural bone, andeight-connected boundary tracking is applied to get the contour data of natural bone.Then, contour matching points are built in the adjacent CT slices in order to meet themachining requirement of layer thickness raised by laser rapid prototyping. Accordingto the matching points, linear interpolation is used to get transition contour data, andthen all natural bone contours are fitted by cubic B-spline curves.Finally, the STLmodel of natural bone is built by the algorithms of shortest diagonal triangulation.It’scould get the information of contour better,and almost no contour with disorder anderror,and could solve the reconstruction problem of complex closed lumen volume.In this paper,A geometric measurement method based on robust statistics andregion-scalable fitting is studied to get the geometrical measurement of complexclosed cavity.compared with the advanced measurement methods,the presentedmeasuring method in this paper has higher accuracy.car wheels CT slice images andhuman bones CT slice images are processed to STL file. Based on the industrial CT data generated STL files directly,obtained artificial bone samples by rapid prototypingprocess,and the cycle time of product design is reduced,verified the correctness of themethod.