scholarly journals Study on 3D reconstruction techniques of rocket body model based on strain monitor

2021 ◽  
Vol 336 ◽  
pp. 02003
Author(s):  
Aihua Chen ◽  
Long Cao ◽  
Guowei Yan ◽  
Ze Xu
Keyword(s):  
3D Reconstruction ◽  
Three Dimensional ◽  
Reconstruction Algorithm ◽  
Maximum Error ◽  
Reconstruction Technique ◽  
Body Model ◽  
Strain Monitoring ◽  
Strain Data ◽  
Dimensional Reconstruction ◽  
Shape Characteristics

A three-dimensional reconstruction technique based on strain monitoring is proposed in this paper. According to the strain data of finite measuring points, the shape characteristics of the whole rocket structure are reconstructed, which provides the basis for the reliability judgment of the structure. Based on the theory of Ko, the 3D reconstruction algorithm for the rocket model of cylindrical structure is realized. The strain nephogram of plate model is simulated by ANASYS. And the strain nephogram is reconstructed by reconstruction algorithm, then compared with the simulation results. The results show that the maximum error between the results of reconstruction and simulation is 1.91%, which indicated that the agreement is great.

The Reconstruction for Han Dynasty Stone Images Based on Three-Dimensional Vision

2014 ◽  
Vol 556-562 ◽  
pp. 5009-5012
Author(s):  
Guang Dong Pan
Keyword(s):  
Mathematical Model ◽  
3D Reconstruction ◽  
Basic Principle ◽  
Projective Transformation ◽  
Three Dimensional ◽  
Reconstruction Algorithm ◽  
Han Dynasty ◽  
Dimensional Reconstruction ◽  
New Research ◽  
Three Dimensional Vision

Mainly studying the three-dimensional reconstruction for multiple Han Dynasty stone images, this paper proposes a 3D reconstruction algorithm based on two images. The author analyzes the basic principle of SIFT matching points detection according to Epipolar geometry constraints and projective transformation of images in 2D plane, and establishes mathematical model for the 3D reconstruction on foundation of sequence images. The feasibility of 3D reconstruction based on the sequence images is approved by simulation for three gray-scale Han Dynasty stone digital images which provides a new research way for identifying the feature of a target by the camera.

scholarly journals Computed Tomography Image under Three-Dimensional Reconstruction Algorithm Based in Diagnosis of Renal Tumors and Retroperitoneal Laparoscopic Partial Nephrectomy

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Haijie Zhang ◽  
Fu Yin ◽  
Liyang Yang ◽  
Anqi Qi ◽  
Weiwei Cui ◽  
...  
Keyword(s):  
Computed Tomography ◽  
3D Reconstruction ◽  
Partial Nephrectomy ◽  
Three Dimensional ◽  
Reconstruction Algorithm ◽  
Ct Images ◽  
Renal Tumors ◽  
Dimensional Reconstruction ◽  
Group A ◽  
Group B

This study was to explore the clinical application value of computed tomography (CT) images based on a three-dimensional (3D) reconstruction algorithm for laparoscopic partial nephrectomy (LPN) in patients with renal tumors. 30 cases of renal cell carcinoma (RCC) patients admitted to the hospital were selected as the research objects and were rolled into two groups using a random table method. The patients who received PLN under the three-dimensional reconstruction and laparoscopic technique were included in the experimental group (group A), and the patients who received LPN using CT images only were included in the control group (group B). In addition, the treatment results of the two groups of patients were compared and analyzed. Results. The effective rate of the established model was 93.3%; the total renal arteriovenous variability of group A (13.3%) was higher than that of group B (6.7%), and the operation time (131.5 ± 32.1 minutes) was much lower than that of group B (158.7 ± 36.2 minutes), showing statistical significance ( P  < 0.05). Conclusion. CT images based on 3D reconstruction algorithms had high clinical application value for LPN in patients with renal tumors, which could improve the efficiency and safety of LPN.

scholarly journals Three-Dimensional Reconstruction Algorithm for CT Pulmonary Angiography in Patients with Pulmonary Embolism Combined with Syncope

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhongxing Zhang ◽  
Yan Zhang ◽  
Xiaohui Wang ◽  
Xiaoli Han ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
3D Reconstruction ◽  
Clinical Characteristics ◽  
Three Dimensional ◽  
Reconstruction Algorithm ◽  
Pulmonary Angiography ◽  
Mesh Simplification ◽  
Ct Pulmonary Angiography ◽  
Dimensional Reconstruction ◽  
The Difference

This paper aimed to study the clinical characteristics of patients with pulmonary embolism (PE) with syncope (PE + S) based on the three-dimensional (3D) reconstruction algorithm in computed tomography (CT) pulmonary angiography (CTPA). In this study, 857 patients with acute PE (APE) who were treated in hospital were selected as the research objects and divided into syncope group (group S) and nonsyncope group (group NS). The 3D reconstruction marching cubes (3DR-MC) algorithm was compared with the traditional MC (T-MC) algorithm and the mesh simplification MC (MMS-MC) algorithm, and the results proved that the running time of the 3DR-MC algorithm on the platform was shorter than that of the other two algorithms. The incidence of syncope in group S in women was higher than that in group NS (51.7% vs. 38.2%). The incidence of syncope classified as high risk in group S was higher than that in group NS, and the mortality rate of pulmonary embolism patients with syncope was higher, and the difference was statistically significant (χ2 = 113.332, P < 0.05 ). The incidence of syncope in group S was higher than that in group NS (χ2 = 4.074, P < 0.05 ). In short, hypertension was an independent risk factor for syncope. PE + S patients could be diagnosed and treated as early as possible based on the clinical characteristics, so as to reduce the adverse consequences of misdiagnosis.

Three-dimensional Reconstruction of Microscopic Image Based on Multi-ST Algorithm

2020 ◽  
Vol 64 (2) ◽  
pp. 20506-1-20506-7
Author(s):  
Min Zhu ◽  
Rongfu Zhang ◽  
Pei Ma ◽  
Xuedian Zhang ◽  
Qi Guo
Keyword(s):  
3D Reconstruction ◽  
Three Dimensional ◽  
Scale Model ◽  
Microscopic Image ◽  
Multi Scale ◽  
Gaussian Pyramid ◽  
Cost Aggregation ◽  
Dimensional Reconstruction ◽  
Image Pairs ◽  
Accurate Matching

Abstract Three-dimensional (3D) reconstruction is extensively used in microscopic applications. Reducing excessive error points and achieving accurate matching of weak texture regions have been the classical challenges for 3D microscopic vision. A Multi-ST algorithm was proposed to improve matching accuracy. The process is performed in two main stages: scaled microscopic images and regularized cost aggregation. First, microscopic image pairs with different scales were extracted according to the Gaussian pyramid criterion. Second, a novel cost aggregation approach based on the regularized multi-scale model was implemented into all scales to obtain the final cost. To evaluate the performances of the proposed Multi-ST algorithm and compare different algorithms, seven groups of images from the Middlebury dataset and four groups of experimental images obtained by a binocular microscopic system were analyzed. Disparity maps and reconstruction maps generated by the proposed approach contained more information and fewer outliers or artifacts. Furthermore, 3D reconstruction of the plug gauges using the Multi-ST algorithm showed that the error was less than 0.025 mm.

scholarly journals Online Measurement of Deposit Surface in Electron Beam Freeform Fabrication

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 4001 ◽  
Author(s):  
Shuhe Chang ◽  
Haoyu Zhang ◽  
Haiying Xu ◽  
Xinghua Sang ◽  
Li Wang ◽  
...  
Keyword(s):  
Electron Beam ◽  
3D Reconstruction ◽  
Three Dimensional ◽  
Thermal Conditions ◽  
Online Measurement ◽  
Three Dimensional Reconstruction ◽  
Continuous Change ◽  
Position Information ◽  
Freeform Fabrication ◽  
Dimensional Reconstruction

In the process of electron beam freeform fabrication (EBF3), due to the continuous change of thermal conditions and variability in wire feeding in the deposition process, geometric deviations are generated in the deposition of each layer. In order to prevent the layer-by-layer accumulation of the deviation, it is necessary to perform online geometry measurement for each deposition layer, based on which the error compensation can be done for the previous deposition layer in the next deposition layer. However, the traditional three-dimensional reconstruction method that employs structured laser cannot meet the requirements of long-term stable operation in the manufacturing process of EBF3. Therefore, this paper proposes a method to measure the deposit surfaces based on the position information of electron beam speckle, in which an electron beam is used to bombard the surface of the deposit to generate the speckle. Based on the structured information of the electron beam in the vacuum chamber, the three-dimensional reconstruction of the surface of the deposited parts is realized without need of additional structured laser sensor. In order to improve the detection accuracy, the detection error is theoretically analyzed and compensated. The absolute error after compensation is smaller than 0.1 mm, and the precision can reach 0.1%, which satisfies the requirements of 3D reconstruction of the deposited parts. An online measurement system is built for the surface of deposited parts in the process of electron beam freeform fabrication, which realizes the online 3D reconstruction of the surface of the deposited layer. In addition, in order to improve the detection stability of the whole system, the image processing algorithm suitable for this scene is designed. The reliability and speed of the algorithm are improved by ROI extraction, threshold segmentation, and expansion corrosion. In addition, the speckle size information can also reflect the thermal conditions of the surface of the deposited parts. Hence, it can be used for online detection of defects such as infusion and voids.

scholarly journals THREE-DIMENSIONAL RECONSTRUCTION BASED ON IMPROVED MARCHING CUBES ALGORITHM

2020 ◽  
Vol 20 (09) ◽  
pp. 2040002
Author(s):  
MONAN WANG ◽  
HAIYANG LUO ◽  
QI CUI
Keyword(s):  
3D Reconstruction ◽  
Medical Image ◽  
Interpolation Method ◽  
Three Dimensional ◽  
Linear Interpolation ◽  
Selection Method ◽  
Marching Cubes ◽  
Dimensional Reconstruction ◽  
Message Mapping ◽  
Opening And Closing

Based on the standard Marching Cubes (MC) algorithm, this paper proposes an improved MC algorithm. First, the original 15 topological configurations in the MC algorithm are increased to 24, which effectively avoid the generation of voids phenomenon. To further improve the speed of three-dimensional (3D) reconstruction, in this paper, the midpoint selection method is used instead of the linear interpolation method, and the 24 configurations are divided into three types. Each class corresponds to a thread. The multi-thread parallel processing is used to improve the calculation speed. The critical region is used to realize multi-thread synchronization, and then we designed a protocol mapping table according to the idea of the message mapping table. The function pointer is triggered by macro. Processing function is called by function pointer and completes the encapsulation of the protocol mapping table, which maintains the opening and closing principle of the class and ensures the scalability of the class. Through the improved MC algorithm accuracy verification and reconstruction speed verification, it is concluded that the improved MC algorithm can make up for the voids problem. By comparing the calculation time under the two platforms of Windows and Linux, the reconstruction speed of the improved MC algorithm is approximately 30% faster than the standard MC algorithm and 40% faster than the Masala algorithm. Finally, the algorithm is applied to the medical image 3D reconstruction system, and the accuracy and applicability of the algorithm are demonstrated by two sets of examples.

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