A Feasibility Study Of Real Time Dynamic Three-dimension Auricular Image Guide Based On Sensors

Objective:To design a real time dynamic three-dimension(3D)auricular image guide based on sensors by means of augmented reality technology for preoperative design of auricular reconstruction and guidance of location and fabrication of auricular framework intraoperatively to improve the effect of auricular reconstruction.Subject and Method:1.Subject:1 head model with the basic structure of human auricle and similar size of adult head,3 volunteers with normal bilateral auricle 2.Method:(1)built digital model of auricle using CT data by image processing software.(2)demonstrated the optimal number and location of sensors.(3)registered the virtual model with the real scene based on three sensors placed on one side of the eyebrow,the nasal tip and the point under the earlobe and projected the 3D model of auricle to the corresponding real auricle through the projector.The infrared motion-capture device was used to capture the changes of the position of the sensors to realize real-time tracking.(4)made qualitative and quantitative evaluation of the registration technology,tracking technology and display technology of the real time dynamic 3D auricular image guide.Results:1.standardized the process of the fabrication of real time dynamic 3D auricular image guide on the head model:(1)a high-quality 3D model of auricle could be established by processing CT image data;(2)it was the best plan in the experimental research stage to place three sensors on one side of the eyebrow,the nasal tip and the point under the earlobe;(3)real time dynamic 3D auricular image guide could be projected to the set area;2.repeated experiments were performed on 3 volunteers to evaluate registration technology,tracking technology and display technology qualitatively and quantitatively:(1)registration technology:high registration accuracy with an average error rate of 2.5%;(2)tracking technology:1)tracking accuracy:clockwise rotation within 30°,tracking accuracy was high with the average error rate less than 2.7%,counterclockwise rotation within 15°,tracking accuracy was high relatively with the average error rate less than 3.5%,2)tracking image deformation:clockwise rotation within 30° and counterclockwise rotation within 15°,tracking image deformation was little with the average error rate less than 2.6%,3)tracking delay:tracking speed was too fast to be tested manually;(3)display technology:3D auricular model was realistic and vivid in real scene,but there were shortcomings such as poor 3D stereoscopic sense and insufficient color contrast.Conclusion:The experimental research demonstrated that the fabrication of real-time dynamic 3D auricular image guide based on sensors was feasible and the 3D auricular image guide had good registration accuracy,good tracking accuracy and tracking image deformation within a certain rotation,good tracking speed and good image quality.Therefore,the guide could be applied to the preoperative design of auricular reconstruction and it had the potential to be used to guide the location of reconstructed ear and framework fabrication intraoperatively.