Precise 3D Model Research Articles

Combining 3D models with 2D infrared images for medical applications.

Infrared images are very useful for providing physiological information, although the representation is two-dimensional. On the other hand, a 3D scanning system is able to generate precise 3D spatial models of the area under study. This paper presents a methodology for combining both imaging modalities into a single representation. The Structure from Motion (SfM) technique is used in order to find the correct infrared camera's positioning and rotations in the space. Then, those 2D infrared images generate a 3D SfM model. Following this stage, the SfM model is replaced by an accurate 3D model from a scanning system, which is wrapped around by the infrared images. The experiments performed with a volunteer's face have shown that the proposed methodology successfully reconstruct a unique 3D surface model, which is able to deliver potential clinical applications.

Low-cost surface reconstruction for aesthetic results assessment and prediction in breast cancer surgery.

The high incidence and low mortality of breast cancer surgery has led to an increasing emphasis on the cosmetic outcome of surgical treatment. Advances in aesthetic evaluation, as well as surgical planning and outcome prediction, have been investigated by using geometrically precise 3D modelling of the breast surface prior to surgery and after the procedure. However, existing solutions are based on expensive site specific setups and remain weakly validated. In this paper, we explore the possibility of using low-cost RGBD cameras as an affordable and mobile system for breast surface reconstruction. The methodology relies on sensor calibration, uncertainty-driven point filtering, dense reconstruction and subsequent multi-view joint optimization to diffuse residual pose errors. Results from a phantom study, with ground truth obtained through commercially available scanners, indicate that the approach is promising with RMS errors in order of 2 mm. A clinical study shows the practical applicability of our method and compares favourably to high-end scanning solutions.

Methods of laser scanning point clouds integration in precise 3D building modelling

3D city models are built on the basis of photogrammetric data, especially laser scanning (LS) data. Due to the increasing levels of accuracy required of 3D city models, terrestrial and airborne laser scanning are the most frequently used technologies. The models are often fragmentary, based on only one type of geodata, e.g. aerial photography or airborne laser scanning (ALS) data. This paper presents various aspects of integrating data from different laser scanning technologies (terrestrial and airborne), which are at the moment considered to be the most detailed and accurate systems for the direct acquiring of 3D geodata. The main issue discussed in the paper is the integration of data in the form of point clouds acquiring from different laser scanning systems. Integration will be understood here as an appropriate processing of both sets of data for orientation into a uniform spatial coordinate system. Thus, the problem of extracting characteristic points common for both sets, in a way which will allow for obtaining a basis for building a complete and accurate 3D city model, will be fundamental. The main challenge when performing this task is to correctly and accurately specify the homologous point pairs used in 3D transformation when both data sets characterise different accuracy, density and content. In the present paper, manual (direct), semi-automatic (indirect determination of characteristic points by approximation) and automatic (3D model) methods for extracting characteristic points are presented, along with the results of an accuracy assessment. Furthermore different transformation methods (isometric, conformal and affine) are also verified, compared and analysed.

실내 정밀 매핑을 위한 회전식 스테레오 라인 카메라 시스템의 캘리브레이션

본 연구는 실내 정밀 매핑과 정교한 영상 기반 서비스에 활용 가능한 실내의 입체 전방위 영상을 취득하는 시스템과 이에 대한 캘리브레이션 방법을 제안한다. 제안된 시스템은 회전식 스테레오 라인 카메라 방식으로 구성되며, 안정적인 입체시와 객체점의 정밀한 결정에 적합한 입체 전방위 영상을 제공한다. 또한, 제안된 시스템의 투영모델을 기반으로 캘리브레이션을 위한 수학적 모델을 도출한다. 이를 통해 캘리브레이션을 수행하여, 실내 공간에 대해 <TEX>${\pm}16cm$</TEX> 이내의 정확도로 객체점을 추정할 수 있었다. 제안된 시스템과 캘리브레이션 방법은 실내의 정밀한 3차원 모델링에 활용될 것이다. We propose a camera system to acquire indoor stereo omni-directional images and its calibration method. These images can be utilized for indoor precise mapping and sophisticated imagebased services. The proposed system is configured with a rotating stereo line camera system, providing stereo omni-directional images appropriate to stable stereoscopy and precise derivation of object point coordinates. Based on the projection model, we derive a mathematical model for the system calibration. After performing the system calibration, we can estimate object points with an accuracy of less than <TEX>${\pm}16cm$</TEX> in indoor space. The proposed system and calibration method will be applied to indoor precise 3D modeling.

Noise reduction of dry vacuum pump using the boundary element method to model impeller blade passage frequency

Acoustic field analysis was conducted to propose noise reduction measures for the suction housing of a vacuum pump used in dentistry. The target frequency for reduction was selected by measuring the sound pressure level during steady-state operation, allowing identification of the primary noise sources through intensity and vibration measurements. The impeller area was analyzed by designing a full-scale analytic model for sound field analysis using reverse engineering, including precise 3D modeling. The inner boundaries were then separately extracted to complete a model for acoustic analysis. The characteristics of the inner suction housing area were analyzed using the Boundary Element Method (BEM). Noise reduction measures were proposed by analyzing the characteristics of the suction housing with respect to the differences in excitation frequency brought about by changing the number of impeller blades used. The acoustic frequency response function (FRF) of the inner suction housing was obtained by applying BEM. The relationships between the suction housing and the noise source were investigated to propose noise reduction measures. The proposed measure of reducing impeller blade number was validated by showing that it would avoid resonance in the suction housing by moving the BPF to a lower frequency. Thus, this study proposed the reduction of the number of impeller blades to reduce the noise of the current suction housing design considerably while maintaining its performance.

Research on Virtual Grinding for Indexable Inserts

The cutting location of cutting-edge curves is obtained by the mathematic models of indexable inserts, and based on the softwares of UG and NCSIMUL, The virtual machining platform is realized to simulate the whole processing of grinding. The Entity modelings of indexable inserts are obtained by Boolean operation in virtual environment, and the basis is presented for analyzing accuracy of the mathematic models and the virtual machining platform. Testing efficiency of NC code and reliability of high speed grinding are improved. This method provides precise 3D models which can be used in the followed works such as finite analysis, CNC machining and so on.

Integration of Image and Laser Scanning Data Based on Selected Example

Abstract The paper aims at presentation of results of research on integration of image and laser data based on selected example. Since a few years the authors have been conducting research on processing image data, and those obtained from laser scanning in the form of the so-called point cloud. In experiments data from terrestrial and mobile laser scanning gained for two different objects were compared: a parish house from Goźlice located in the open-air ethnographic museum at the village of Tokarnia, Poland, and part of the Cracow-Warsaw railway line. The results of those experiments proved that data in the form of point cloud were not always sufficient for a precise 3D model reconstruction. Supplementing point clouds with photogrammetric images seems to be the best solution.

A sensor skid for precise 3D modeling of production lines

Abstract. Motivated by the increasing need of rapid characterization of environments in 3D, we designed and built a sensor skid that automates the work of an operator of terrestrial laser scanners. The system combines terrestrial laser scanning with kinematic laser scanning and uses a novel semi-rigid SLAMmethod. It enables us to digitize factory environments without the need to stop production. The acquired 3D point clouds are precise and suitable to detect objects that collide with items moved along the production line.

Archaeological documentation based on geomatic techniques for Roman amphitheater in Amman City

As the archaeological heritage constitutes the basic record of the past human activities, its protection and preservation is therefore imperative for all generations to benefit. The preservation process used to be upon the documentation through description and photographs by archaeologists which do not bring as exact or efficient results as in modern digital documentation and studies. Modern geomatic techniques offer an optimal digital documentation methodology to keep records and construct realistic three-dimensional (3D) digital models for the whole as well as each monument alone, connecting these parts to its original location on the site. We integrated field surveying techniques and orthophoto to document, preserve, and revitalize the Roman amphitheater and its surroundings at the center of Amman. A very precise 3D model of the site was built using more than 3,000 measured points in x, y, and z. The purpose of measuring a great number of points is to represent each stone and change in the site to document it and keep records of its precise dimensions and location. The resulted model is very easy to rebuild and reconstruct in case of emergency. Hundreds of digital photos were stacked to build a very precise 3D view with very high accuracy and precision.

Potentialities and limitations of a database constructing three-dimensional virtual bone models

3D bone reconstructions performed during general clinical practice are of limited use for preclinical research, education, and training purposes. For this reason, we are constructing a database of human 3D virtual bone models compiled from computer tomography (CT) scans. CT data sets were post-processed using Amira(®) 5.2 software. In each cut, bone structures were isolated using semiautomatic labeling program codes. The software then generated extremely precise 3D bone models in STL format (standard triangulated language). These bone models offer a sustainable source of information for morphologic studies and investigations of biomechanical bony characteristics in complex anatomic regions. Regarding educational value and student acceptance models were introduced during bedside teaching and evaluated by medical students. The current database is comprised of 131 pelvises and 120 femurs (ø 60years, ø 172cm, ø 76kg), and is continuously growing. To date, 3D morphometric analyses of the posterior ring and the acetabulum have been successfully completed. Eighty students (96%) evaluated instruction with virtual 3D bone models as "good" or "very good". The majority of students want to increase learning with virtual bone models covering various regions and diseases. With consistent and steadily increasing case numbers, the database offers a sustainable alternative to human cadaver work for practical investigations. In addition, it offers a platform for education and training.

The Parametric Modeling and Contact Strength Analysis for the Wind Power Increasing Gear

In this paper, the precise 3D model of the wind power increasing gear was set up by based on the parametric designing method of Pro/Program, then the contact strength of the gear was analyzed by the FEM and the Hertz theoretical value was calculated, the FEM and the Hertz results were contrasted in order to confirm the applicability of the numerical analysis in wind power gear contact analysis. Finally, the corresponding analysis conclusion was received.The researching results offered a effective theoretical basis for the optimization design and analysis of the wind increasing gear.

Model Reconstruction from CMM and Optical Scanning Data for Reverse Engineering

This paper introduces a novel modeling method using points acquired by a touch probe on a coordinate measuring machine and an optical scanner. An improved iterative closet point algorithm is adopted in order to transform the optical scanning data and the high precision points captured by a touch probe into a common coordinate system. A data merging method is also used to keep the high precision of feature surfaces and then unified into a precise 3D model. Experimental results demonstrate the efficiency of the presented method, which enhances the flexibility of digitization while maintaining the accuracy of feature surfaces.

Geometry-based 3D face morphology analysis: soft-tissue landmark formalization

The face is perhaps the most important human anatomical part, and its study is very important in many fields, such as the medical one and the identification one. Technical literature presents many works on this topic involving bi-dimensional solutions. Even if these solutions are able to provide interesting results, they are strongly subjected to images distortion. Thanks to the significant improvements obtained in the 3D scanner domain (photogrammetry for instance), today it is possible to replace the 2D images with more precise and complete 3D models (triangulated points clouds). Working on three-dimensional data, in fact, it is possible to obtain a more complete set of information about the face morphology. At present, even if it is possible to find interesting papers on this field, there is the lack of a complete protocol for converting the big amount of data coming from the three-dimensional point clouds in a reliable set of facial data, which could be employed for recognition and medical tasks. Starting from some anatomical human face concepts, it has been possible to understand that some soft-tissue landmarks could be the right data set for supporting many processes working on three-dimensional models. So, working in the Differential Geometry domain, through the Coefficients of the Fundamental Forms, the Principal Curvatures, Mean and Gaussian Curvatures and also with the derivatives and the Shape and Curvedness Indexes, the study has proposed a structured methodology for soft-tissue landmark formalization in order to provide a methodology for their automatic identification. The proposed methodology and its sensitivity have been tested with the involvement of a series of subjects acquired in different scenarios.

Dynamics Analysis for Naval Gun with Consideration of Contact between Arc and Gear

The effect of contact between cradle arc and main gear of elevating mechanism on muzzle disturbance is studied.The precise 3D models of involute straight tooth gear and arc are constructed by PRO/E software.Considering the contact between cradle arc and main gear of elevating mechanism,the nonlinear finite element model for naval gun is established.The results of numerical simulation show that the contact/impact has great effect on muzzle disturbance.

Development of a semi-automated method for mitral valve modeling with medial axis representation using 3D ultrasound

Precise 3D modeling of the mitral valve has the potential to improve our understanding of valve morphology, particularly in the setting of mitral regurgitation (MR). Toward this goal, the authors have developed a user-initialized algorithm for reconstructing valve geometry from transesophageal 3D ultrasound (3D US) image data. Semi-automated image analysis was performed on transesophageal 3D US images obtained from 14 subjects with MR ranging from trace to severe. Image analysis of the mitral valve at midsystole had two stages: user-initialized segmentation and 3D deformable modeling with continuous medial representation (cm-rep). Semi-automated segmentation began with user-identification of valve location in 2D projection images generated from 3D US data. The mitral leaflets were then automatically segmented in 3D using the level set method. Second, a bileaflet deformable medial model was fitted to the binary valve segmentation by Bayesian optimization. The resulting cm-rep provided a visual reconstruction of the mitral valve, from which localized measurements of valve morphology were automatically derived. The features extracted from the fitted cm-rep included annular area, annular circumference, annular height, intercommissural width, septolateral length, total tenting volume, and percent anterior tenting volume. These measurements were compared to those obtained by expert manual tracing. Regurgitant orifice area (ROA) measurements were compared to qualitative assessments of MR severity. The accuracy of valve shape representation with cm-rep was evaluated in terms of the Dice overlap between the fitted cm-rep and its target segmentation. The morphological features and anatomic ROA derived from semi-automated image analysis were consistent with manual tracing of 3D US image data and with qualitative assessments of MR severity made on clinical radiology. The fitted cm-reps accurately captured valve shape and demonstrated patient-specific differences in valve morphology among subjects with varying degrees of MR severity. Minimal variation in the Dice overlap and morphological measurements was observed when different cm-rep templates were used to initialize model fitting. This study demonstrates the use of deformable medial modeling for semi-automated 3D reconstruction of mitral valve geometry using transesophageal 3D US. The proposed algorithm provides a parametric geometrical representation of the mitral leaflets, which can be used to evaluate valve morphology in clinical ultrasound images.

Digital modeling of world's first known length reference unit: The Nippur cubit rod

Abstract It is a fact that the most important thing for transmitting cultural heritage to posterity starts with a sensitive documentation step. Up to the present, there have been many developments in documentation of cultural heritage by developing technology, and contemporary documentation techniques have progressed speedily. Nowadays besides of a sensitive documentation, rapidness has gain importance for the sake of time and cost. Because of these facts, the techniques that provide fast and reliable documentation and modeling like digital close-range photogrammetry and laser scanning became preferable with respect to classical architectural methods. In this paper, the studies of precise measurement, 3D modeling and documentation of Nippur Cubit is presented. The Nippur cubit–the first known standard measure of length–was a heavy copper bar, unearthed at Nippur on the Euphrates River dating from about 2650 B.C. This ancient measuring device is nowadays exposed in the Archeological Museum of Istanbul, Turkey. For the purpose of 3D modeling and archiving of the mentioned object, digital close-range photogrammetry and laser scanning technology were applied and results obtained from these two techniques were compared.

The Project ThermalMapper – Thermal 3D Mapping of Indoor Environments for Saving Energy

Abstract Heat and air conditioning losses in buildings and factories lead to a large amount of wasted energy. The Action Plan for Energy Efficiency of the Commission of the European Communities (2008) estimates that the largest cost-effective energy savings potential lies in residential (≈ 27%) and commercial (≈ 30%) buildings. Imagine a technology that creates a precise digital 3D model of heat distribution and heat flow enabling one to detect all sources of wasted energy and to modify buildings to reach these savings. This paper presents our overall approach to map indoor environments with thermal data in 3D.

A Combined Modeling Method Based on Multiple-Sensor Integrated Measuring System for Reverse Engineering

In this paper a combined modeling method using digitized points measured by multiple-sensor integrated measuring system with a touch probe and a optical scanning probe is presented. The optical scanning data in the form of triangulated mesh and the high precision data captured by a touch probe on an integrated measuring system are transformed into a common coordinate system by the worktable for registration and improved ICP algorithm. A data merging method is used to keep the high precision of feature surfaces.The merging data is unified into a precise 3D model in CAD software environment based on the strategy for optimization reconstruction. Experimental results demonstrate the efficiency of the proposed method, which enhances the flexibility of digitizing while maintaining the accuracy of feature surfaces.

Calculation of Grinding Wheel Profile and 3D Simulation for Grinding Screw Rotor Flute

In order to describe the forming grinding principle of screw rotor, the mathematical model of screw rotor’s helical groove and forming grinding wheel are established by differential geometry theory and numerical analysis method. And the contact line equation is derived. To optimize the traditional method of calculating forming grinding wheel by known rotor end section profile, a numerical analysis method (Accumulated Chord Length Parameter Method) has been presented in detail. This method can improve the efficiency and reliability of the calculation of forming grinding wheel axial profile. Taking the asymmetry linear screw rotor (female) as an example, this paper calculates the grinding wheel axial profile and draws it using special designed software. The simulation examples are done by CAD (Computer Aided Design) based on the secondary development technology of UG. This study provides a precise 3D model which can be used in areas such as finite element analysis and virtual testing experiments.

The structure of the crust in TESZ area by kriging interpolation

A precise 3D model of the crust is necessary to start any tectonic or geodynamic interpretation. It is also essential for seismic interpretations of structures lying below as well as for correct analysis of shallow structures using reflection seismics. During the last decades, a number of wide-angle refraction experiments were performed on the territory of central and eastern Europe (POLONAISE’97, CELEBRATION 2000, SUDETES 2003), resulting in many high quality 2D models. It is an interesting and complicated transition zone between Precambrian and Palaeozoic Platforms. This paper presents 3D model of the velocity distribution in the crust and upper mantle interpolated from 2D models of the structure along 33 profiles. The obtained model extends to a depth of 50 km and accurately describes the main features of the crustal structures of Poland and surrounding areas. Different interpolation techniques (Kriging, linear) are compared to assure maximum precision. The final model with estimated uncertainty is an interesting reference of the area for other studies.