| As a kind of minimally invasive surgery, the advantages of needle insertion are minimal trauma, faster post operative recovery, less complication etc. In the procedures of chemotherapy, surgical diagnosis, therapy, experimental research and so on, the insertion needle tip needs to accurately reach at the target. This paper is aimed at meeting the needs of needle insertion experiments. The properties of prepared soft tissue were studied experimentally. The soft tissue deformation and needle deflection in the needle insertion procedures were studied respectively.In order to make the high mechanical properties of PVA hydrogel and liver transparency,with different proportion of polyvinyl alcohol, dimethyl sulfide and deionized water in the preparation process of soft tissue. This is close to the preparation, so we regard it prosthesis tissue.The purpose of measure the deformation and the deflection, a platform for experimental needle were built. The power unit of the puncture test is provided by universal love nano displacement technology(Shanghai) Co. Ltd. Experimental image acquisition system is composed Camera, lens and back light source.Write the needle puncture motion control program in Labview, write the program image acquisition systemin the C++, this system can satisfy all requirements of the late experiment.In the process of needle puncture experiment, the graphic is dealt with morphplogical. Compared to three edge defection operator of Robert, Soble and Log in the process of image morphology. And the image is treated for expasion, corrosion, fill, bridge, burr and other operations. Identifier and needle tip of puncture needle of soft tissue is extrated. The dynamic process of soft tissue and puncture needle is analyzed. The curve of soft tissue deformation and puncture needle deflection is fitted. And the effect of needle velocity, puncture depth and puncture type on soft tissue deformation and puncture needle deflection is analyzed. |
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