Search results for "reconstruction"
showing 10 items of 784 documents
123D Catch: efficiency, accuracy, constraints and limitations in architectural heritage field
2013
Today, the accurate and detailed reconstruction of geometric models of real objects has become a common process. The diffusion of Image-based 3D modeling techniques, through image-based free, low cost and open source software, have increased drastically in the past few years, especially in the sector of Cultural Heritage (Architecture, Archeology, Urban planning). Nevertheless, web based software (ARC3D, 123D Catch, Hyp3D, my3Dscanner) offer another opportunity respect the desktop systems: they use the power of cloud computing to carry out a semi-automatic data processing. In this way is overcome the considerably slowing-down of the computer of hardware-heavy approaches. Our research inves…
Reconstruction Improvement in Integral Fourier Holography by Micro-Scanning Method
2015
Although integral holography has many promising advantages in the field of 3D imaging, the resolution of reconstructed holographic image is still limited by the insufficient information captured. To improve the reconstruction quality, an integral Fourier holographic imaging method based on micro-scanning of the micro-lens array is proposed in this paper. The micro-scanning of the micro-lens array can increase the sampling rate in spatial frequency domain and the information of the generated Fourier hologram, which will eventually eliminate the overlapping effect in the reconstructed 3D image. Experiments for different micro-scanning modes are carried out to verify the feasibility of the pro…
Shape Reconstruction of Metallic Objects by Artificial Vision
1997
Quality control in industrial applications has greatly benefited from the development of tools like artificial vision. The artificial vision approach of quality control has the advantage of being able to perform both non-destructive and contactless controls as well as to work mostly in real time. However, in the case of non planar objects to be controlled, dimensional control may become hard to realize. Indeed, due to the bidimensional aspect of the images, a loss of information is unavoidable. Consequently, obtaining depth information from a planar image is not obvious. Most of the existing methods use several cameras1 or several light sources2, this leads to an increase in the processing …
Motion estimation and reconstruction of piecewise planar scenes from two views
2010
The task of recovering the camera motion relative to the environment (motion estimation) is fundamental to many computer vision applications. We present an algorithm for reconstruction of piece-wise planar scenes from only two views and based on minimum line correspondences. We first recover camera rotation by matching vanishing points based on the methods already exist in the literature and then recover the camera translation by searching among a family of hypothesized planes passing through one line. Unlike algorithms based on line segments, the presented algorithm does not require an overlap between two line segments or more than one line correspondence across more than two views to reco…
Phantomuntersuchung zur Optimierung der Spiral-CT und 3 D-Rekonstruktion des Tracheobronchialsystems
1996
PURPOSE To optimise three-dimensional spiral CT of the tracheobronchial tree using adequate acquisition and reconstruction parameters for spiral CT of the chest. MATERIAL AND METHODS Qualitative and quantitative assessment of different 3 D reconstructions of two test objects of the tracheobronchial tree depending on section thickness, reconstruction interval, pitch, and reconstruction algorithm used in spiral CT (Siemens, Somatom plus S) of the chest. The frequency of volume and stairstep artifacts was evaluated. The 3 D reconstructions were generated using a seeded VOI-technique (Allegro, ISG). RESULTS Reduction of artifacts was achieved by decreasing section thickness. Increasing overlap …
FAST EDGE-FILTERED IMAGE UPSAMPLING.
2011
We present a novel edge preserved interpolation scheme for fast upsampling of natural images. The proposed piecewise hyperbolic operator uses a slope-limiter function that conveniently lends itself to higher-order approximations and is responsible for restricting spatial oscillations arising due to the edges and sharp details in the image. As a consequence the upsampled image not only exhibits enhanced edges, and discontinuities across boundaries, but also preserves smoothly varying features in images. Experimental results show an improvement in the PSNR compared to typical cubic, and spline-based interpolation approaches.
Proximal Tibiofibular Joint Reconstruction With Autogenous Semitendinosus Tendon Graft
2013
Isolated and chronic anterolateral instability of the proximal tibiofibular joint (TFJ) is an uncommon condition, generally linked to an unrecognized or unhealed dislocation of the TFJ. Clinically, abnormal anterior movement of the head of the fibula is detected. In acute injuries conservative management should be preferred, whereas surgical treatment have been advocated in patients with chronic TFJ instability. Authors describe a new surgical reconstruction technique for chronic instability of the proximal TFJ using an autogenous semitendinosus tendon. The graft is passed through fibular and tibia tunnels and fixed with 2 interference screws. The tibial tunnel is reamed from the posterolat…
3D-CT von Frakturen: Vergleich von Volumen- und Oberflächen-Rekonstruktionen
1998
Purpose The comparison of volume rendering (VR) and surface rendering (SSD) for demonstrating fractures from spiral-CT data. Materials and methods Standardized VR and SSD projections were produced from 50 spiral CT scans of 50 consecutive patients with fractures. Appropriate multiplanar reformattings (MPR) were used as the standard. Results SSD provided sufficient information in 31/50 cases. Results of VR were not significantly different (33/50). VR was superior in demonstrating 6/7 craniofacial fractures and 3/3 calcaneal fractures. SSD was superior for visualizing 2/3 shoulder fractures and 2/2 elbow fractures. Conclusion VR is a flexible technique for the depiction of fractures and the a…
<title>Multiresolution description of range images through 2D quincunx wavelet analysis</title>
1999
In this paper, we present a method for performing a multi- scale analysis on range images by using the wavelet transform, that is capable of revealing multi-resolution information. An accurate non-contact optical system based upon laser triangulation is used to determine the depth information of the object being scanned. The resulting range image is treated as a gray-level image by using a multi- resolution approach based on the generalization of the cascade algorithm using the quincunx wavelet transform. The quincunx wavelet assures very fine analysis. This method allows reconstruction of non-subsampled images that correspond to decompositions previously done at chosen scales. Multi-resolu…
Three-dimensional ultrasonography in prenatal diagnosis
1995
Within the past five years, 3D ultrasonography has developed to the degree that it offers both the patient and the examiner an entirely new visual experience in prenatal diagnosis. With the system described here (Kretz-technik, Austria), any desired plane can be displayed within the stored volume, and within seconds a high-quality 3D surface or transparent image can be calculated and displayed on the ultrasound monitor without need for an external workstation. All of this can be performed routinely in the clinical setting. Since 1989 we have routinely examined a total of 458 fetuses (242 normal and 216 with anomalies) between 16 and 38 weeks of gestation, supplementing our conventional 2D u…