Three-dimensional Motion Skeleton Reconstruction Algorithm for Gymnastic Dancing Movements

Aiming at the problem of inaccurate matching results in the traditional three-dimensional reconstruction algorithm of gymnastic skeleton, a three-dimensional motion skeleton reconstruction algorithm of gymnastic dance action is proposed. Taking the center of gravity of the human body as the origin, the position of other nodes in the camera coordinate system relative to the center point of the human skeleton model is calculated, and the human skeleton data collection is completed through action division and posture feature calculation. Polynomial density is introduced into the integration of convolution surface, and the human body model of convolution surface is established according to convolution surface. By using the method of binary parameter matching, the accuracy of the matching results is improved, and the three-dimensional skeleton of gymnastic dance movement is reconstructed. The experimental results show that the fitting degree between the proposed method and the actual reconstruction result is 99.8%, and the reconstruction result of this algorithm has high accuracy.

Three-Dimensional Reconstruction of Two-Dimensional Cardiovascular Angiography Image Sequences by Local Threshold Segmentation Algorithm

The study focused on the extraction of cardiovascular two-dimensional angiography sequences and the three-dimensional reconstruction based on the local threshold segmentation algorithm. Specifically, the two-dimensional cardiovascular angiography sequence was extracted first, and Gaussian smoothing was adopted for image preprocessing. Then, optimize maximum between-class variance (OSTU) was compared with the traditional two-dimensional OSTU and fast two-dimensional OSTU and applied in the segmentation of cardiovascular angiography images. It was found that the cardiovascular structure itself was continuous, the contrast agent diffused relatively evenly in the blood vessel, and the gray level of the blood vessel was also continuous. The degree of smoothness was consistent in all directions by Gaussian smoothing, avoiding the direction deviation of the smoothened image. The operation time (0.59 s) of the optimize OSTU was significantly shorter than that of traditional OSTU (35.68 s) and fast two-dimensional OSTU (6.34 s) ( P < 0.05 ). The local threshold segmentation algorithm can realize the continuous edge extraction of blood vessels and accurately reflect the stenosis of blood vessels. The results of blood vessel diameter measurement showed that the diameter from the end of blood vessel to the intersection varied linearly from 5.5 mm to 9.0 mm. In short, the optimize OSTU demonstrated good segmentation effects and fast calculation time; it successfully extracted continuous two-dimensional cardiovascular angiography images and can be used in three-dimensional reconstruction of cardiovascular images.

SSOP Three-Dimensional Reconstruction of Tibia and Fibula for Applications in Biomechanical Fracture Models

Context: Non-fatal injuries represent a public health issue. Among them, lower limb fractures have a large impact on the costs related to orthopedic treatments. In this work, a three-dimensional reconstruction of the tibia and fibula was performed for biomechanical applications with the purpose of defining the 3D reconstruction parameters that allow reducing patients’ radiation exposure and computational costs. Method: For the 3D reconstruction, a computerized tomography taken from a volunteer was used, as well as two software applications specialized in DICOM image reconstruction (Mimics Research and 3DSlicer). The number of images included in the volume was modified, and the results were compared. The quality of the reconstructed volumes was verified by comparing the reference volume reconstructed with the total number of images/slices vs. the modified volumes. The MeshLab software was used for this purpose. The analyzed parameters were the distance differences between the reference and the alternative models, as well as the qualitative curvature analysis. Results: The ANOVA results for the Max (maximum distance between meshes) response shows that software and slices are significant factors. However, the software-slices interaction did not have a significant influence. As for the RMS (root mean square) distance response, software, slices, and the software-slices interaction are not significant. For the Mean distance response, slices and the software-slices interaction are not significant. Nevertheless, software significantly influences the response. These results suggest a potential way to reduce the computational cost and the patient’s radiation exposure in future biomechanical and preoperatory analyses, since the same quality can be obtained by including fewer 2D images in the reconstruction. Conclusions: The reconstructed surfaces are smoother when Mimics is used, even though the same smoothness factor was employed in both software applications during the reconstruction. When 16 slices are used (retained every 16 images from the complete original model), the distance differences increased for both bones (tibia and fibula). For the RMS, reducing the number of slices and using either one of the two applications analyzed would not show any significant differences in the reconstruction, thus allowing the potential reduction of radiation exposure of the patient. Acknowledgements: The authors are grateful to Universidad Nacional de Colombia for funding the project “Estado de esfuerzos en un elemento de osteosíntesis en la consolidación de una fractura de miembro inferior”.