New approach for the digital reconstruction of complex mine faults and its application in mining

Visualization of complex geological structures can technically support the accurate prediction and prevention of coal mine disasters.This study proposed a new digital reconstruction method to visualize geological structures based on establishing a virtual model in the digital twin system.This methodology for the digital reconstruction of complex fault structures comprises the following four aspects:(1)collection and fdelity of multi-physical feld data of the fault structures,(2)the transmission of multi-physical feld data,(3)the normalization of multi-physical feld data,and(4)digital model reconstruction of fault structures.The key scientifc issues of this methodology to be resolved include in situ fdelity of multi-feld data and normalized programming of multi-source data.In addition,according to the geological background and conditions in Da’anshan coal mine in western Beijing,China,a preliminary attempt is made to reconstruct a digital model of fault and fold structures using the methodology proposed in this study.

Application of 3D Digital Reconstruction and Printing to the Diagnosis and Treatment of Iliac Vein Compression

The objective of this research was to explore the feasibility and clinical application of a new diagnostic imaging method for the diagnosis and treatment of iliac vein compression(IVC)based on three-dimensional(3D)digital reconstruction and printing.This study included patients with chronic venous disease(CVD)who were admitted to the Department of Vascular Surgery,Shanghai Ninth People’s Hospital,Shanghai Jiao Tong University School of Medicine,from January to March,2019,and underwent computed tomography venography(CTV)to detect IVC.CTV findings were used to reconstruct 3D-printed models of blood vessels.A total of 17 patients(5 men and 12 women)with IVC,who were primarily diagnosed with CTV,were included in this study.In addition,24 significant venous compression sites were found in 17 patients,of which 7 patients had only one compression site(41.2%),nine patients had two compression sites(52.9%),and one patient had three compression sites(5.9%).3D digital reconstruction and printing is a convenient,noninvasive,and accurate diagnostic imaging method that provides a clear and accurate evaluation of veins and arteries,as well as the anatomical positional relationship for the diagnosis and treatment of IVC.

Mechanism analysis of cheetah’s high-speed locomotion based on digital reconstruction

As the fastest land animal,cheetah has important reference significance for the research of high-speed quadruped robots in terms of its body structure,motion characteristics and control mechanism.In this paper,we used digital reconstruction to analyze the mechanism of the cheetah’s high-speed movement.Considering the body size and quality of a real cheetah,a simplified virtual model of cheetah was built.Using the D-H method,the kinematics and dynamics of the cheetah’s leg mechanism were established.By using the foot trajectory data of the cheetah’s running gait obtained from biological research,each joint angle,virtual leg length,leg-to-ground contact angle,leg energy,joint torque,and the manipulability of the leg mechanism were analyzed and compared in the time dimension.Finally,the high-speed motion law of engineering guiding significance was extracted.

Digital Imaging Reconstruction from Multiple Angle Diversity Using Digital Filtering Technique

Microwave diffraction tomography is a process to infer the internal structure of an objectfrom multiple angle views of microwave diffraction shadow. Being sensitive to variations in refractive index of the object, the procedure can be used to measure permittivity distributions within dielectric objects and to image soft tissues for biomedical applications. The optimal resolution distance obtainable is half a wavelength, but this can rarely be achieved because of practical limitations. Some procedures, however, are available to improve the practical resolution. One, which is suitable for microwave tomography, is to use multiple angle views data and to combine the resulting images. The other, which is suitable for improving the image reconstruction resolution, is to use the digital filtering technique and the filtered backpropagation algorithm. A system operating over the X-band microwave frequency is described and some experimental results for objects in air are given.

Digital measurement of bone tumor volume by CT three-dimensional reconstruction technology

Objective To discuss the measurement of bone tumor volume on the basis of three dimensional images segmentation technology. Methods Twenty patients with lacunar bone tumor from Tianjin Hospital and Tongji Hospital were included in the

A Method of Digitally Reconstructed Radiographs Based on Medical CT Images

A complete and detail method is described to get digitally reconstructed radiographs （DRRs）. Casting rays to traverse CT images, computing CT values of resample points by interpolation, then converting CT value to its attenuation coefficient by using simplified segment function. Finally, DRRs enhancement is made to get the better display of region of interest （ROI）, and a new way is adopted to adjust the customization coefficient. The experimental results show that the proposed method is effective in generating the satisfied DRRs.

Application of a medical image processing system in liver transplantation

BACKGROUND: At present, imaging is used not only to show the form of images, but also to make three-dimensional (3D) reconstructions and visual simulations based on original data to guide clinical surgery. This study aimed to assess the use of a medical image-processing system in liver transplantation surgery. METHODS: The data of abdominal 64-slice spiral CT scan were collected from 200 healthy volunteers and 37 liver cancer patients in terms of hepatic arterial phase, portal phase, and hepatic venous phase. A 3D model of abdominal blood vessels including the abdominal aorta system, portal vein system, and inferior vena cava system was reconstructed by an abdominal image processing system to identify vascular variations. Then, a 3D model of the liver was reconstructed in terms of hepatic segmentation and liver volume was calculated. The Free Form modeling system with a PHANTOM force feedback device was used to simulate the real liver transplantation environment, in which the total process of liver transplantation was completed. RESULTS: The reconstructed model of the abdominal blood vessels and the liver was clearly demonstrated to be three-dimensionally consistent with the anatomy of the liver, in which the variations of abdominal blood vessels were identified and liver segmentation was performed digitally. In the model, liver transplantation was simulated subsequently, and different modus operandi were selected successfully. CONCLUSION: The digitized medical image processing system may be valuable for liver transplantation.

The reconstruction of diffractive object digital hologramat a short distance

By using a spherical wave as the reference wave, we recorded the in-line phase-shifting digital hologram of the 25th element of Chinese standard No. 3 resolution test pattern, and gave the corresponding numerical reconstructed results. Some problems concerning with the digital hologram recording and reconstruction of the diffractive object at a short distance are discussed. The experimental result shows that the resolution of the reconstructed image is better than 10μm, which is the limit by using this experimental arrangement.

Three-Dimensional Computerized Tomography-Assisted Identification of Necrotic Volume, Distribution, Shape and Prognosis of Collapse in ONFH

Objective: We constructed 3D-model of ONFH in computer according to three-dimensional computerized tomography (3D-CT) data. We determined the location and volume of necrosis to investigate its clinical efficacy. Method: Totally 92 hips (59 cases) with ONFH (44 males, 15 females) were included, with mean age of 37.5 years (range from 26 to 58). Totally 20 cases (35 hips) were induced by corticosteroid (CTSs), 31 (49 hips) induced by alcohol, 4 (4 hips) induced by trauma and 4 (4 hips) idiopathic. All the hips were categorized into stage ARCO II. Finally diagnosed by MRI, all hips were scanned by CT to acquire data in DICOM format. The images were imported into software to extract 3D-shape of femoral heads, necrotic foci, their volumes and distribution in each quadrant. Deviation of volumes between digital image and biopsy specimen was analyzed by SAS9.1 package. Correlativity between collapse and volume of necrosis under specific pathogeneses was also analyzed. Among the cases necessitating total hip arthroplasty (THA) due to advancing to ARCO III, we randomly selected 8 of them to perform 3D-CT scanning thrice prior to surgical operation. Total femoral heads harvested were torn asunder. Cubic capacity of femoral heads and necrotic foci were hereby measured and compared with those acquired from digital models. Result: Through the digital model, necrotic foci were found mainly locating within the super lateral portion of femoral head, coinciding with those observed in biopsy specimen. Average volumetric ratio of digitally acquired necrosis focus/femoral head in 58 collapsed hips was 36.8%. The ratio of the 34 hips without collapse was 17.3%. In collapsed femoral heads, the distribution of necrosis focus was 23.4% in quadrant 1 (q1), 23.6% in q2, 12.1% in q3, 14.4% in q4, 9.0% in q5, 11.8% in q6, 1.6% in q7 and 3.9% in q8. In femoral heads without collapse, the distribution was 34.2% in q1, 29.6% in q2, 11.8% in q3, 11.3% in q4, 6.0% in q5, 6.0% in q6, 0.5% in q7 and 0.4% in q8. As for the average cubic capacities of femoral heads and necrotic foci, those acquired from the digital model and biopsy specimen had no significant difference in matched-pairs test (t = -1.49, P = 0.179 for femoral heads and t = -1.52, P = 0.172 for necrotic foci). There was significant difference (F = 2.720, P = 0.035 P was respectively 0.0001 and 0.0005). Decision tree model showed that 94.6% (53/56) hips would progress into collapse if the volumetric ratio of necrotic tissue was over 23.48%. Otherwise, if distribution in q2 was over 45.13%, 83.3% (5/6) hips would progress into collapse. No collapse (0/30) would occur if the distribution of necrotic tissue in q2 was under 45.13%. Conclusion: Digital 3D-model reconstructed from CT scanning can precisely incarnate spatial orientation of necrotic foci in femoral head. Multinomial logistic regression and decision-making tree shows that volumetric ratio of necrotic tissues plays an important role in anticipating collapse of femoral head.

Compressed sensing reconstruction of sparse spectrum based on digital micro-mirror device platform

A new method which employs compressive sensing(CS) to reconstruct the sparse spectrum is designed and experimentally demonstrated. On the basis of CS theory, the simulation results indicate that the probability of reconstruction is high when the step of the sparsity adaptive matching pursuit algorithm is confirmed as 1. Contrastive analysis for four kinds of commonly used measurement matrices: part Hadamard, Bernoulli, Toeplitz and Circular matrix, has been conducted. The results illustrate that the part Hadamard matrix has better performance of reconstruction than the other matrices. The experimental system of the spectral compression reconstruction is mainly based on the digital micro-mirror device(DMD). The experimental results prove that CS can reconstruct sparse spectrum well under the condition of 50% sampling rate. The system error 0.0781 is obtained, which is defined by the average value of the 2-norm. Furthermore, the proposed method shows a dominant ability to discard redundancy.