Three-dimensional Reconstruction Technique Research Articles

Research on Key Techniques of Virtual Arthroscopic Knee Surgery Training System

This paper discussed the three-dimensional reconstruction technique from medical image, the interaction technology, and some other key techniques needed to be solved urgently of the virtual surgery training system. On the basis of research results, we built a surgery training system.

Asteroid (2867) Steins: Shape, topography and global physical properties from OSIRIS observations

The Rosetta spacecraft flew by Asteroid (2867) Steins on 5 September 2008, allowing the onboard OSIRIS cameras to collect the first images of an E-type asteroid. We implemented several three-dimensional reconstruction techniques to retrieve its shape. Limb profiles, combined with stereo control points, were used to reconstruct an approximate shape model. This model was refined using a stereophotoclinometry technique to accurately retrieve the topography of the hemisphere observed by OSIRIS. The unseen part of the surface was constrained by the technique of light curves inversion.The global shape resembles a top with dimensions along the principal axes of inertia of 6.83×5.70×4.42km. It is conspicuously more regular than other small asteroids like (233) Eros and (25143) Itokawa. Its mean radius is Rm=2.70km and its equivalent radius (radius of a sphere of equivalent volume) is Rv=2.63km. The north pole is oriented at RA=99±5° and Dec=−59±5°, which implies a very large obliquity of 172° and a retrograde rotation.Maps of the gravitational field and slopes were calculated for the well-imaged part of the asteroid. Together with the shape, they helped characterizing the most prominent topographic features identified at the surface of (2867) Steins: an equatorial ridge restricted to the extremities of the long axis, a large crater having dimensions of 2100×1800m in the southern hemisphere, and an elongated hill in the northern hemisphere. We conjecture that the equatorial ridge was formed by centrifugal acceleration as the asteroid was spun up by the Yarkovsky–O’Keefe–Radzievskii–Paddack effect.

Application of three-dimensional reconstruction technique based on CT-MRI fusion in skull base surgery

To study the application of three-dimensional reconstruction technique based on CT-MRI fusion in skull base surgery. To acquire the thin layer CT scan and MRI scanned images, to achieve image registration, fusion, segmentation and 3D visualization by using self-preparation software, to operate, observe and measure models by using methods of endoscopic observation, volume rendering segmentation, automatically and manually measure. The center of the eye and foramen magnum in CT-MRI were used as point registration. Good coincidence of important anatomic landmarks were formed in the image fusion. The boundary of spotted graphical was clear and complete. The models showed a complete, continuous, smooth surface. Virtual endoscopy could display the inside three-dimensional structures of skull from nasal with fluent operations of rotation and transparency. The boundary of skull stump segmented after volume rendering segmentation was clear and smooth, and it could show bone signs and soft tissue models together. Cooperation of automatic measurement method [(32.007 ± 15.311) mm] and the manual measurement method [(30.240 ± 15.169) mm] for measuring the maximum diameters of the tumor model, the difference was significant (t = 8.409, P < 0.05). The method of selecting the center of the eye and foramen magnum in point matching is scientific, simple and easy to operate. The models reconstructed based on CT-MRI fusion images can accurately reflect the size of the soft tissue and be better measured through the automatic measurement. Reconstruction models can be observed through the way of virtual endoscopic within the nasal cavity or volume rendering segmentation from outside to inside to frustrate the relationship of skull structures. Three-dimensional reconstruction techniques based on CT-MRI fusion in skull base surgery can be used to plan surgical approach, to assess the risk of surgery and to achieve space measurements, and it laid the foundation for the three-dimensional navigation.

Application of a digital three-dimensional reconstruction technique in the diagnosis and treatment of hepatic alveolar echinococcosis

Objective To investigate the value of a digital three-dimensional reconstruction technique in the treatment of hepatic alveolar echinococcosis (HAE).Methods The computed tomography scan data for 13 patients with HAE who were admitted to the First Affiliated Hospital of Xinjiang Medical University from February 2011 to October 2011 were reconstructed and analyzed by a three-dimensional reconstruction system to assess resectability,and to facilitate surgical planning and individualized virtual surgery.The results of preoperative analysis were compared with the results of actual operations.Results The three-dimensional models of the liver were reconstructed successfully,and intrahepatie lesions and vessels were clearly displayed.One patient received an autologous liver transplantation,10 underwent hepatectomy,and 2 received percutaneous transhepatic cholangial drainage.Virtual operation planning was carried out for 11 patients using the three-dimensional reconstruction system.The mean volume of the liver to be resected was predicted to be 920 ml (range,339-2678 ml),and the mean percentage of liver to be resected to the total liver volume was predicted to be 45％ ( range,23％ -68％ ).The mean volume o[ the actual liver resection was 834 ml (range,315-2250 m[),and the mean percentage of actual liver resected to the total liver volume was 42％ (range,22％ -70％ ),which was consistent with the results of preoperative three-dimensional reconstruction.All patients were followed up for 2-8 months,and no severe complications such as liver failure,hemorrhage and bile leakage were detected.Conclusion Digital three-dimen-sional reconstruction is helpful in the diagnosis and treatment of HAE and effectively reduces surgical risks. Key words: Hepatic alveolar echinococcosis; Three-diamensional reconstruction; Surgical planning

The formation mechanisms of interlocked microstructures in low-carbon high-strength steel weld metals

Microstructural features and the formation mechanisms of interlocked microstructures of acicular ferrite in a low-carbon high-strength steel weld metal were investigated by means of computer-aided three-dimensional reconstruction technique and electron backscattered diffraction analysis. Multiple nucleation on inclusions, sympathetic nucleation or repeated nucleation, hard impingement, mutual intersection, and fixed orientation relationships of acicular ferrite grains were observed. They were all responsible for the formation of interlocked microstructures in the weld metal. During the process of isothermal transformation, the pre-formed acicular ferrite laths or plates partitioned austenite grains into many small and separate regions, and the growth of later formed acicular ferrite grains was confined in these small regions. Thus, the crystallographic grain size became smaller with the increasing holding time. ► Acicular ferrite is formed by multiple nucleation and sympathetic nucleation. ► Hard impingement and intersection of ferrite grains occur at later stages. ► The pre-formed ferrite laths partition austenite grains into smaller regions. ► The growth of later formed ferrite grains is confined in the smaller regions.

Silica–rubber microstructure visualised in three dimensions by focused ion beam–scanning electron microscopy

A focused ion beam-scanning electron microscope (FIB-SEM) technique for three-dimensional reconstruction and representation of material microstructures was applied to a silica-filled synthetic rubber for the first time. Backscattered electron imaging allowed differentiation between rubber matrix, silica filler and zinc oxide (used as an activator for the sulphur vulcanisation reaction). Subsequent image processing allowed three-dimensional isosurface model generation of the particulate structure within the rubber composite and separation of zinc oxide from the silica filler. The potential for development and application of this technique using finite element analysis modelling is also highlighted.

Accurate 3-Dimensional Imaging Method Based on Extended RPM for Rotating Target Model

Three-dimensional (3-D) reconstruction techniques employed by airborne radars are essential for object recognition in scenarios where optically vision is blurry, and are required for the monitoring of disasters and coast-guard patrols. There have been reports on 3-D reconstruction methods that exploit the layover appearing in inverse synthetic aperture radar (ISAR) imagery, which are suitable for the recognition of artificial targets such as buildings, aircraft or ships. However, existing methods assume only a point target or the aggregate of point targets, and most require the tracking of the multiple points over sequential ISAR images. In the case of a solid object with a continuous boundary, such as a wire or polyhedral structure, the positioning accuracy of such methods is severely degraded owing to scattering centers continuously shifting on the target surface with changes in the rotation angle. To overcome this difficulty, this paper extends the original Range Points Migration (RPM) method to the ISAR observation model, where a double mono-static model with two transmitting and receiving antennas is introduced to suppress cross-range ambiguity. The results of numerical simulation and experimental validation demonstrate that the extended RPM method has a distinct advantage for accurate 3-D imaging, even for non-point targets.

Applying Computer Techniques in Repairing Mild Mandibular Asymmetry With High-Density Porous Polyethylene

The purpose of this study was to explore a new method to repair mild mandibular asymmetry using computer-aided design technique. Medical three-dimensional image reconstruction and mirror technique were applied to design individual Medpor implant before operation. A surgical procedure was performed in 9 patients with mild mandibular asymmetry according to the preoperative planning. The Medpor implants in the body were displayed using surface rendering technique after operation, and the postoperative evaluation was performed using matching technique. All the patients had an ideal clinical outcome, with no complications. Virtual images from preoperative design and postoperative three-dimensional images were registered and superimposed onto each other. The percentage of matching was 87.6% to 96.8% with an average of 93.8%±2.4%. The computer techniques play an important role in repairing mandibular asymmetry and will be used widely in craniofacial surgery.

Rigorous Proofs For Cone-Beam Reconstruction

Cone beam reconstruction is a three-dimensional tomographic reconstruction technique with the potential capability of producing images with temporal contrast, and three-dimensional spatial resolution.In this paper we present a rigorous proof of the novel three-dimensional inversion formula developed by B. Smith and derive strict tipper bound« for the error

Three‐dimensional computed topography analysis of a patient with an unusual anatomy of the maxillary second and third molars

We present a case of a patient with rare anatomy of a maxillary second molar with three mesiobuccal root canals and a maxillary third molar with four separate roots, identified using multi-slice computed topography (CT) and three-dimensional reconstruction techniques. The described case enriched/might enrich our knowledge about possible anatomical aberrations of maxillary molars. In addition, we demonstrate the role of multi-slice CT as an objective tool for confirmatory diagnosis and successful endodontic management.

Three-Dimensional Reconstruction of Renovascular-Tumor Anatomy to Facilitate Zero-Ischemia Partial Nephrectomy

Zero-ischemia robotic and laparoscopic partial nephrectomy, a novel concept, eliminates ischemia to the tumor-free normal kidney. Anatomic microdissection of tertiary/higher-order tumor-specific arteries is performed to selectively devascularize only the tumor, maintaining normal perfusion of the remaining kidney. A thorough understanding of renovascular tumor anatomy is essential. Based on 0.5-mm-slice thickness computed tomography scans, we developed a novel three-dimensional (3D) reconstruction technique that fuses three key anatomic aspects: surface-rendered tumor, semitransparent kidney, and extra- and intrarenal arterial anatomy. Four central completely intrarenal hilar masses underwent 3D reconstruction for surgical navigation during zero-ischemia partial nephrectomy. Negative surgical margins were obtained in all four cases, with no intraoperative complications or transfusions. For these challenging laparoscopically invisible masses, 3D image navigation precisely identified tumor-specific arterial branches, thus facilitating zero-ischemia partial nephrectomy without hilar cross clamping.

Reevaluating the Arthropod Tree of Life

Arthropods are the most diverse group of animals and have been so since the Cambrian radiation. They belong to the protostome clade Ecdysozoa, with Onychophora (velvet worms) as their most likely sister group and tardigrades (water bears) the next closest relative. The arthropod tree of life can be interpreted as a five-taxon network, containing Pycnogonida, Euchelicerata, Myriapoda, Crustacea, and Hexapoda, the last two forming the clade Tetraconata or Pancrustacea. The unrooted relationship of Tetraconata to the three other lineages is well established, but of three possible rooting positions the Mandibulata hypothesis receives the most support. Novel approaches to studying anatomy with noninvasive three-dimensional reconstruction techniques, the application of these techniques to new and old fossils, and the so-called next-generation sequencing techniques are at the forefront of understanding arthropod relationships. Cambrian fossils assigned to the arthropod stem group inform on the origin of arthropod characters from a lobopodian ancestry. Monophyly of Pycnogonida, Euchelicerata, Myriapoda, Tetraconata, and Hexapoda is well supported, but the interrelationships of arachnid orders and the details of crustacean paraphyly with respect to Hexapoda remain the major unsolved phylogenetic problems.

ACCELERATION OF CORONAL MASS EJECTIONS FROM THREE-DIMENSIONAL RECONSTRUCTION OFSTEREOIMAGES

We employ a three-dimensional (3D) reconstruction technique, for the first time to study the kinematics of six coronal mass ejections (CMEs), using images obtained from the COR1 and COR2 coronagraphs on board the twin STEREO spacecraft, as also the eruptive prominences (EPs) associated with three of them using images from the Extreme UltraViolet Imager (EUVI). A feature in the EPs and leading edges (LEs) of all the CMEs was identified and tracked in images from the two spacecraft, and a stereoscopic reconstruction technique was used to determine the 3D coordinates of these features. True velocity and acceleration were determined from the temporal evolution of the true height of the CME features. Our study of kinematics of the CMEs in 3D reveals that the CME leading edge undergoes maximum acceleration typically below 2R$_\{odot}$. The acceleration profiles of CMEs associated with flares and prominences exhibit different behaviour. While the CMEs not associated with prominences show a bimodal acceleration profile, those associated with prominences do not. Two of the three associated prominences in the study show a high and rising value of acceleration up to a distance of almost 4R$_\{odot}$ but acceleration of the corresponding CME LE does not show the same behaviour, suggesting that the two may not be always driven by the same mechanism. One of the CMEs, although associated with a C-class flare showed unusually high acceleration of over 1500 m s$^{-2}$. Our results therefore suggest that only the flare-associated CMEs undergo residual acceleration, which indicates that the flux injection theoretical model holds good for the flare-associated CMEs, but a different mechanism should be considered for EP-associated CMEs.

Sirolimus‐eluting stent fracture detection by three‐dimensional optical coherence tomography

Stent fracture has emerged as a complication of drug-eluting stent and is now recognized as contributing to in-stent restenosis and possibly stent thrombosis. Although optical coherence tomography (OCT) can detect stent fractures in the absence of circumference struts, it is challenging to visualize stent fractures with only cross-sectional OCT images. We describe two cases of restenosis with stent fracture detected by a novel three-dimensional OCT image reconstruction technique. This technique allows identification of a single stent fracture even in the absence of angiographic signs.

Measurement of impinging butane flame using combined optical system with digital speckle tomography

Three-dimensional density distributions of an impinging and eccentric flame were measured experimentally using a combined optical system with digital speckle tomography. In addition, a three-dimensional temperature distribution of the flame was reconstructed from an ideal gas equation based on the reconstructed density data. The flame was formed by the ignition of premixed butane/air from air holes and impinged upward against a plate located 24 mm distance from the burner nozzle. In order to verify the reconstruction process for the experimental measurements, numerically synthesized phantoms of impinging and eccentric flames were derived and reconstructed using a developed three-dimensional multiplicative algebraic reconstruction technique (MART). A new scanning technique was developed for the accurate analysis of speckle displacements necessary for investigating the wall jet regions of the impinging flame at which a sharp variation of the flow direction and pressure gradient occur. The reconstructed temperatures by the digital speckle tomography were applied to the boundary condition for numerical analysis of a flame impinged plate. Then, the numerically calculated temperature distribution of the upper side of the flame impinged plate was compared to temperature data taken by an infrared camera. The absolute average uncertainty between the numerical and infrared camera data was 3.7%.

Three-dimensional image reconstruction of radiation-sensitive samples with x-ray diffraction microscopy

Coherent diffraction microscopy determines the three-dimensional (3D) structure of a noncrystalline sample by acquiring a set of diffraction patterns at multiple sample orientations. In order to achieve a high spatial resolution, it usually requires a large number of diffraction patterns with small increments of tilt angles. However, this is not easily attainable for biological or other radiation-sensitive samples due to the radiation damage issue. With the constraint that only a limited number of diffraction patterns is available, a new method is proposed to optimize the effect of these data for three-dimensional image reconstruction. The method combines the concepts of selecting angles with a constant slope increment, the pseudopolar Fourier transform, and the guided hybrid input-output method for direct 3D phase retrieval. Based on simulated and experimental data, it is shown that the proposed method has a better accuracy than some existing three-dimensional image reconstruction techniques. The method is also examined for its stability and consistency by reducing data points used for image reconstruction. The relationship between the number of diffraction patterns used and the accuracy of the reconstructed images is also studied.

Multidetector CT evaluation of central airways stenoses: Comparison of virtual bronchoscopy, minimal-intensity projection, and multiplanar reformatted images

Aims:To evaluate the diagnostic utility of virtual bronchoscopy, multiplanar reformatted images, and minimal-intensity projection in assessing airway stenoses.Settings and Design:It was a prospective study involving 150 patients with symptoms of major airway disease.Materials and Methods:Fifty-six patients were selected for analysis based on the detection of major airway lesions on fiber-optic bronchoscopy (FB) or routine axial images. Comparisons were made between axial images, virtual bronchoscopy (VB), minimal-intensity projection (minIP), and multiplanar reformatted (MPR) images using FB as the gold standard. Lesions were evaluated in terms of degree of airway narrowing, distance from carina, length of the narrowed segment and visualization of airway distal to the lesion.Results:MPR images had the highest degree of agreement with FB (Κ = 0.76) in the depiction of degree of narrowing. minIP had the least degree of agreement with FB (Κ = 0.51) in this regard. The distal visualization was best on MPR images (84.2%), followed by axial images (80.7%), whereas FB could visualize the lesions only in 45.4% of the cases. VB had the best agreement with FB in assessing the segment length (Κ = 0.62). Overall there were no statistically significant differences in the measurement of the distance from the carina in the axial, minIP, and MPR images. MPR images had the highest overall degree of confidence, namely, 70.17% (n = 40).Conclusion:Three-dimensional reconstruction techniques were found to improve lesion evaluation compared with axial images alone. The technique of MPR images was the most useful for lesion evaluation and provided additional information useful for surgical and airway interventions in tracheobronchial stenosis. minIP was useful in the overall depiction of airway anatomy.

A Novel Technique for Three-Dimensional Reconstruction for Surgical Simulation Around the Craniocervical Junction Region

Performing surgeries on the craniocervical junction presents a technical challenge for operating surgeons. Three-dimensional (3D) reconstruction and surgical simulation have improved the efficacy and success rate of surgeries. The aim of this study was to create a 3D, digitized visible model of the craniocervical junction region to help realize accurate simulation of craniocervical surgery on a graphic workstation. Transverse sectional anatomy data for the study were chosen from the first Chinese visible human. Manual axial segmentation of the skull base, cervical spine, cerebellum, vertebral artery, internal carotid artery, sigmoid sinus, internal jugular vein, brain stem, and spinal cord were carried out by using Photoshop software. The segmented structures were reconstructed in 3 dimensions with surface and volume rendering to accurately display 3D models spatially. In contrast to conventional 3D reconstruction techniques that are based on computed tomography and magnetic resonance imaging Digital Imaging and Communications in Medicine (DICOM) inputs and provide mostly osseous details, this technique can help to illustrate the surrounding soft tissue structure and provide a realistic surgical simulation. The reconstructed 3D model was successfully used in simulating complex procedures in the virtual environment, including the transoral approach, bone drillings, and clivus resection.

Shape Measurement of Steel Strips Using a Laser-Based Three-Dimensional Reconstruction Technique

Quality control is of utmost importance in the metal industry. It requires online measurement and inspection systems which provide precise feedback to closed-loop controllers in industrial facilities. In rolled products, shape is one of the main quality criteria. In this paper, a low-cost real-time 3-D shape measurement system for long flat (FL)-rolled products based on laser triangulation is proposed. The system provides online measurements of two geometrical features of the shape of rolled products: flatness and width. The proposed system is based on 3-D surface reconstruction of rolled products with which flatness can be measured accurately and continuously across the whole width of the strip. Three-dimensional surface reconstruction provides highly accurate width measurements not only of FL products, as do most other systems, but also of non-FL products. The accuracy of the laser extraction method used to reconstruct the surface of the rolled products is evaluated, as well as the online performance of the system.

EMPIRICAL RECONSTRUCTION AND NUMERICAL MODELING OF THE FIRST GEOEFFECTIVE CORONAL MASS EJECTION OF SOLAR CYCLE 24

We analyze the kinematics and morphology of a coronal mass ejection (CME) from 2010 April 3, which was responsible for the first significant geomagnetic storm of solar cycle 24. The analysis utilizes coronagraphic and heliospheric images from the two STEREO spacecraft, and coronagraphic images from SOHO/LASCO. Using an empirical three-dimensional (3D) reconstruction technique, we demonstrate that the CME can be reproduced reasonably well at all times with a 3D flux rope shape, but the case for a flux rope being the correct interpretation is not as strong as some events studied with STEREO in the past, given that we are unable to infer a unique orientation for the flux rope. A model with an orientation angle of –80° from the ecliptic plane (i.e., nearly N-S) works best close to the Sun, but a model at 10° (i.e., nearly E-W) works better far from the Sun. Both interpretations require the cross section of the flux rope to be significantly elliptical rather than circular. In addition to our empirical modeling, we also present a fully 3D numerical MHD model of the CME. This physical model appears to effectively reproduce aspects of the shape and kinematics of the CME's leading edge. It is particularly encouraging that the model reproduces the amount of interplanetary deceleration observed for the CME during its journey from the Sun to 1 AU.