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Sample records for 3d wavelet based

  1. 3D Wavelet-Based Filter and Method

    DOEpatents

    Moss, William C.; Haase, Sebastian; Sedat, John W.

    2008-08-12

    A 3D wavelet-based filter for visualizing and locating structural features of a user-specified linear size in 2D or 3D image data. The only input parameter is a characteristic linear size of the feature of interest, and the filter output contains only those regions that are correlated with the characteristic size, thus denoising the image.

  2. An efficient and robust 3D mesh compression based on 3D watermarking and wavelet transform

    NASA Astrophysics Data System (ADS)

    Zagrouba, Ezzeddine; Ben Jabra, Saoussen; Didi, Yosra

    2011-06-01

    The compression and watermarking of 3D meshes are very important in many areas of activity including digital cinematography, virtual reality as well as CAD design. However, most studies on 3D watermarking and 3D compression are done independently. To verify a good trade-off between protection and a fast transfer of 3D meshes, this paper proposes a new approach which combines 3D mesh compression with mesh watermarking. This combination is based on a wavelet transformation. In fact, the used compression method is decomposed to two stages: geometric encoding and topologic encoding. The proposed approach consists to insert a signature between these two stages. First, the wavelet transformation is applied to the original mesh to obtain two components: wavelets coefficients and a coarse mesh. Then, the geometric encoding is done on these two components. The obtained coarse mesh will be marked using a robust mesh watermarking scheme. This insertion into coarse mesh allows obtaining high robustness to several attacks. Finally, the topologic encoding is applied to the marked coarse mesh to obtain the compressed mesh. The combination of compression and watermarking permits to detect the presence of signature after a compression of the marked mesh. In plus, it allows transferring protected 3D meshes with the minimum size. The experiments and evaluations show that the proposed approach presents efficient results in terms of compression gain, invisibility and robustness of the signature against of many attacks.

  3. Improving 3D Wavelet-Based Compression of Hyperspectral Images

    NASA Technical Reports Server (NTRS)

    Klimesh, Matthew; Kiely, Aaron; Xie, Hua; Aranki, Nazeeh

    2009-01-01

    Two methods of increasing the effectiveness of three-dimensional (3D) wavelet-based compression of hyperspectral images have been developed. (As used here, images signifies both images and digital data representing images.) The methods are oriented toward reducing or eliminating detrimental effects of a phenomenon, referred to as spectral ringing, that is described below. In 3D wavelet-based compression, an image is represented by a multiresolution wavelet decomposition consisting of several subbands obtained by applying wavelet transforms in the two spatial dimensions corresponding to the two spatial coordinate axes of the image plane, and by applying wavelet transforms in the spectral dimension. Spectral ringing is named after the more familiar spatial ringing (spurious spatial oscillations) that can be seen parallel to and near edges in ordinary images reconstructed from compressed data. These ringing phenomena are attributable to effects of quantization. In hyperspectral data, the individual spectral bands play the role of edges, causing spurious oscillations to occur in the spectral dimension. In the absence of such corrective measures as the present two methods, spectral ringing can manifest itself as systematic biases in some reconstructed spectral bands and can reduce the effectiveness of compression of spatially-low-pass subbands. One of the two methods is denoted mean subtraction. The basic idea of this method is to subtract mean values from spatial planes of spatially low-pass subbands prior to encoding, because (a) such spatial planes often have mean values that are far from zero and (b) zero-mean data are better suited for compression by methods that are effective for subbands of two-dimensional (2D) images. In this method, after the 3D wavelet decomposition is performed, mean values are computed for and subtracted from each spatial plane of each spatially-low-pass subband. The resulting data are converted to sign-magnitude form and compressed in a

  4. 3D Gabor wavelet based vessel filtering of photoacoustic images.

    PubMed

    Haq, Israr Ul; Nagoaka, Ryo; Makino, Takahiro; Tabata, Takuya; Saijo, Yoshifumi

    2016-08-01

    Filtering and segmentation of vasculature is an important issue in medical imaging. The visualization of vasculature is crucial for the early diagnosis and therapy in numerous medical applications. This paper investigates the use of Gabor wavelet to enhance the effect of vasculature while eliminating the noise due to size, sensitivity and aperture of the detector in 3D Optical Resolution Photoacoustic Microscopy (OR-PAM). A detailed multi-scale analysis of wavelet filtering and Hessian based method is analyzed for extracting vessels of different sizes since the blood vessels usually vary with in a range of radii. The proposed algorithm first enhances the vasculature in the image and then tubular structures are classified by eigenvalue decomposition of the local Hessian matrix at each voxel in the image. The algorithm is tested on non-invasive experiments, which shows appreciable results to enhance vasculature in photo-acoustic images.

  5. Spherical 3D isotropic wavelets

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2012-04-01

    Context. Future cosmological surveys will provide 3D large scale structure maps with large sky coverage, for which a 3D spherical Fourier-Bessel (SFB) analysis in spherical coordinates is natural. Wavelets are particularly well-suited to the analysis and denoising of cosmological data, but a spherical 3D isotropic wavelet transform does not currently exist to analyse spherical 3D data. Aims: The aim of this paper is to present a new formalism for a spherical 3D isotropic wavelet, i.e. one based on the SFB decomposition of a 3D field and accompany the formalism with a public code to perform wavelet transforms. Methods: We describe a new 3D isotropic spherical wavelet decomposition based on the undecimated wavelet transform (UWT) described in Starck et al. (2006). We also present a new fast discrete spherical Fourier-Bessel transform (DSFBT) based on both a discrete Bessel transform and the HEALPIX angular pixelisation scheme. We test the 3D wavelet transform and as a toy-application, apply a denoising algorithm in wavelet space to the Virgo large box cosmological simulations and find we can successfully remove noise without much loss to the large scale structure. Results: We have described a new spherical 3D isotropic wavelet transform, ideally suited to analyse and denoise future 3D spherical cosmological surveys, which uses a novel DSFBT. We illustrate its potential use for denoising using a toy model. All the algorithms presented in this paper are available for download as a public code called MRS3D at http://jstarck.free.fr/mrs3d.html

  6. ICER-3D: A Progressive Wavelet-Based Compressor for Hyperspectral Images

    NASA Technical Reports Server (NTRS)

    Kiely, A.; Klimesh, M.; Xie, H.; Aranki, N.

    2005-01-01

    ICER-3D is a progressive, wavelet-based compressor for hyperspectral images. ICER-3D is derived from the ICER image compressor. ICER-3D can provide lossless and lossy compression, and incorporates an error-containment scheme to limit the effects of data loss during transmission. The three-dimensional wavelet decomposition structure used by ICER-3D exploits correlations in all three dimensions of hyperspectral data sets, while facilitating elimination of spectral ringing artifacts. Correlation is further exploited by a context modeler that effectively exploits spectral dependencies in the wavelet-transformed hyperspectral data. Performance results illustrating the benefits of these features are presented.

  7. Wavelet-based fMRI analysis: 3-D denoising, signal separation, and validation metrics.

    PubMed

    Khullar, Siddharth; Michael, Andrew; Correa, Nicolle; Adali, Tulay; Baum, Stefi A; Calhoun, Vince D

    2011-02-14

    We present a novel integrated wavelet-domain based framework (w-ICA) for 3-D denoising functional magnetic resonance imaging (fMRI) data followed by source separation analysis using independent component analysis (ICA) in the wavelet domain. We propose the idea of a 3-D wavelet-based multi-directional denoising scheme where each volume in a 4-D fMRI data set is sub-sampled using the axial, sagittal and coronal geometries to obtain three different slice-by-slice representations of the same data. The filtered intensity value of an arbitrary voxel is computed as an expected value of the denoised wavelet coefficients corresponding to the three viewing geometries for each sub-band. This results in a robust set of denoised wavelet coefficients for each voxel. Given the de-correlated nature of these denoised wavelet coefficients, it is possible to obtain more accurate source estimates using ICA in the wavelet domain. The contributions of this work can be realized as two modules: First, in the analysis module we combine a new 3-D wavelet denoising approach with signal separation properties of ICA in the wavelet domain. This step helps obtain an activation component that corresponds closely to the true underlying signal, which is maximally independent with respect to other components. Second, we propose and describe two novel shape metrics for post-ICA comparisons between activation regions obtained through different frameworks. We verified our method using simulated as well as real fMRI data and compared our results against the conventional scheme (Gaussian smoothing+spatial ICA: s-ICA). The results show significant improvements based on two important features: (1) preservation of shape of the activation region (shape metrics) and (2) receiver operating characteristic curves. It was observed that the proposed framework was able to preserve the actual activation shape in a consistent manner even for very high noise levels in addition to significant reduction in false

  8. 3-D surface profilometry based on modulation measurement by applying wavelet transform method

    NASA Astrophysics Data System (ADS)

    Zhong, Min; Chen, Feng; Xiao, Chao; Wei, Yongchao

    2017-01-01

    A new analysis of 3-D surface profilometry based on modulation measurement technique by the application of Wavelet Transform method is proposed. As a tool excelling for its multi-resolution and localization in the time and frequency domains, Wavelet Transform method with good localized time-frequency analysis ability and effective de-noizing capacity can extract the modulation distribution more accurately than Fourier Transform method. Especially for the analysis of complex object, more details of the measured object can be well remained. In this paper, the theoretical derivation of Wavelet Transform method that obtains the modulation values from a captured fringe pattern is given. Both computer simulation and elementary experiment are used to show the validity of the proposed method by making a comparison with the results of Fourier Transform method. The results show that the Wavelet Transform method has a better performance than the Fourier Transform method in modulation values retrieval.

  9. A novel 3D wavelet based filter for visualizing features in noisy biological data

    SciTech Connect

    Moss, W C; Haase, S; Lyle, J M; Agard, D A; Sedat, J W

    2005-01-05

    We have developed a 3D wavelet-based filter for visualizing structural features in volumetric data. The only variable parameter is a characteristic linear size of the feature of interest. The filtered output contains only those regions that are correlated with the characteristic size, thus denoising the image. We demonstrate the use of the filter by applying it to 3D data from a variety of electron microscopy samples including low contrast vitreous ice cryogenic preparations, as well as 3D optical microscopy specimens.

  10. Improved 3D wavelet-based de-noising of fMRI data

    NASA Astrophysics Data System (ADS)

    Khullar, Siddharth; Michael, Andrew M.; Correa, Nicolle; Adali, Tulay; Baum, Stefi A.; Calhoun, Vince D.

    2011-03-01

    Functional MRI (fMRI) data analysis deals with the problem of detecting very weak signals in very noisy data. Smoothing with a Gaussian kernel is often used to decrease noise at the cost of losing spatial specificity. We present a novel wavelet-based 3-D technique to remove noise in fMRI data while preserving the spatial features in the component maps obtained through group independent component analysis (ICA). Each volume is decomposed into eight volumetric sub-bands using a separable 3-D stationary wavelet transform. Each of the detail sub-bands are then treated through the main denoising module. This module facilitates computation of shrinkage factors through a hierarchical framework. It utilizes information iteratively from the sub-band at next higher level to estimate denoised coefficients at the current level. These de-noised sub-bands are then reconstructed back to the spatial domain using an inverse wavelet transform. Finally, the denoised group fMRI data is analyzed using ICA where the data is decomposed in to clusters of functionally correlated voxels (spatial maps) as indicators of task-related neural activity. The proposed method enables the preservation of shape of the actual activation regions associated with the BOLD activity. In addition it is able to achieve high specificity as compared to the conventionally used FWHM (full width half maximum) Gaussian kernels for smoothing fMRI data.

  11. 3D steerable wavelets in practice.

    PubMed

    Chenouard, Nicolas; Unser, Michael

    2012-11-01

    We introduce a systematic and practical design for steerable wavelet frames in 3D. Our steerable wavelets are obtained by applying a 3D version of the generalized Riesz transform to a primary isotropic wavelet frame. The novel transform is self-reversible (tight frame) and its elementary constituents (Riesz wavelets) can be efficiently rotated in any 3D direction by forming appropriate linear combinations. Moreover, the basis functions at a given location can be linearly combined to design custom (and adaptive) steerable wavelets. The features of the proposed method are illustrated with the processing and analysis of 3D biomedical data. In particular, we show how those wavelets can be used to characterize directional patterns and to detect edges by means of a 3D monogenic analysis. We also propose a new inverse-problem formalism along with an optimization algorithm for reconstructing 3D images from a sparse set of wavelet-domain edges. The scheme results in high-quality image reconstructions which demonstrate the feature-reduction ability of the steerable wavelets as well as their potential for solving inverse problems.

  12. 3D High Resolution Mesh Deformation Based on Multi Library Wavelet Neural Network Architecture

    NASA Astrophysics Data System (ADS)

    Dhibi, Naziha; Elkefi, Akram; Bellil, Wajdi; Amar, Chokri Ben

    2016-12-01

    This paper deals with the features of a novel technique for large Laplacian boundary deformations using estimated rotations. The proposed method is based on a Multi Library Wavelet Neural Network structure founded on several mother wavelet families (MLWNN). The objective is to align features of mesh and minimize distortion with a fixed feature that minimizes the sum of the distances between all corresponding vertices. New mesh deformation method worked in the domain of Region of Interest (ROI). Our approach computes deformed ROI, updates and optimizes it to align features of mesh based on MLWNN and spherical parameterization configuration. This structure has the advantage of constructing the network by several mother wavelets to solve high dimensions problem using the best wavelet mother that models the signal better. The simulation test achieved the robustness and speed considerations when developing deformation methodologies. The Mean-Square Error and the ratio of deformation are low compared to other works from the state of the art. Our approach minimizes distortions with fixed features to have a well reconstructed object.

  13. Lossless to lossy compression for hyperspectral imagery based on wavelet and integer KLT transforms with 3D binary EZW

    NASA Astrophysics Data System (ADS)

    Cheng, Kai-jen; Dill, Jeffrey

    2013-05-01

    In this paper, a lossless to lossy transform based image compression of hyperspectral images based on Integer Karhunen-Loève Transform (IKLT) and Integer Discrete Wavelet Transform (IDWT) is proposed. Integer transforms are used to accomplish reversibility. The IKLT is used as a spectral decorrelator and the 2D-IDWT is used as a spatial decorrelator. The three-dimensional Binary Embedded Zerotree Wavelet (3D-BEZW) algorithm efficiently encodes hyperspectral volumetric image by implementing progressive bitplane coding. The signs and magnitudes of transform coefficients are encoded separately. Lossy and lossless compressions of signs are implemented by conventional EZW algorithm and arithmetic coding respectively. The efficient 3D-BEZW algorithm is applied to code magnitudes. Further compression can be achieved using arithmetic coding. The lossless and lossy compression performance is compared with other state of the art predictive and transform based image compression methods on Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) images. Results show that the 3D-BEZW performance is comparable to predictive algorithms. However, its computational cost is comparable to transform- based algorithms.

  14. MRS3D: 3D Spherical Wavelet Transform on the Sphere

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2011-12-01

    Future cosmological surveys will provide 3D large scale structure maps with large sky coverage, for which a 3D Spherical Fourier-Bessel (SFB) analysis is natural. Wavelets are particularly well-suited to the analysis and denoising of cosmological data, but a spherical 3D isotropic wavelet transform does not currently exist to analyse spherical 3D data. We present a new fast Discrete Spherical Fourier-Bessel Transform (DSFBT) based on both a discrete Bessel Transform and the HEALPIX angular pixelisation scheme. We tested the 3D wavelet transform and as a toy-application, applied a denoising algorithm in wavelet space to the Virgo large box cosmological simulations and found we can successfully remove noise without much loss to the large scale structure. The new spherical 3D isotropic wavelet transform, called MRS3D, is ideally suited to analysing and denoising future 3D spherical cosmological surveys; it uses a novel discrete spherical Fourier-Bessel Transform. MRS3D is based on two packages, IDL and Healpix and can be used only if these two packages have been installed.

  15. 3D fast wavelet network model-assisted 3D face recognition

    NASA Astrophysics Data System (ADS)

    Said, Salwa; Jemai, Olfa; Zaied, Mourad; Ben Amar, Chokri

    2015-12-01

    In last years, the emergence of 3D shape in face recognition is due to its robustness to pose and illumination changes. These attractive benefits are not all the challenges to achieve satisfactory recognition rate. Other challenges such as facial expressions and computing time of matching algorithms remain to be explored. In this context, we propose our 3D face recognition approach using 3D wavelet networks. Our approach contains two stages: learning stage and recognition stage. For the training we propose a novel algorithm based on 3D fast wavelet transform. From 3D coordinates of the face (x,y,z), we proceed to voxelization to get a 3D volume which will be decomposed by 3D fast wavelet transform and modeled after that with a wavelet network, then their associated weights are considered as vector features to represent each training face . For the recognition stage, an unknown identity face is projected on all the training WN to obtain a new vector features after every projection. A similarity score is computed between the old and the obtained vector features. To show the efficiency of our approach, experimental results were performed on all the FRGC v.2 benchmark.

  16. 3-D wavelet compression and progressive inverse wavelet synthesis rendering of concentric mosaic.

    PubMed

    Luo, Lin; Wu, Yunnan; Li, Jin; Zhang, Ya-Qin

    2002-01-01

    Using an array of photo shots, the concentric mosaic offers a quick way to capture and model a realistic three-dimensional (3-D) environment. We compress the concentric mosaic image array with a 3-D wavelet transform and coding scheme. Our compression algorithm and bitstream syntax are designed to ensure that a local view rendering of the environment requires only a partial bitstream, thereby eliminating the need to decompress the entire compressed bitstream before rendering. By exploiting the ladder-like structure of the wavelet lifting scheme, the progressive inverse wavelet synthesis (PIWS) algorithm is proposed to maximally reduce the computational cost of selective data accesses on such wavelet compressed datasets. Experimental results show that the 3-D wavelet coder achieves high-compression performance. With the PIWS algorithm, a 3-D environment can be rendered in real time from a compressed dataset.

  17. Wavelet-Based 3D Reconstruction of Microcalcification Clusters from Two Mammographic Views: New Evidence That Fractal Tumors Are Malignant and Euclidean Tumors Are Benign

    PubMed Central

    Batchelder, Kendra A.; Tanenbaum, Aaron B.; Albert, Seth; Guimond, Lyne; Kestener, Pierre; Arneodo, Alain; Khalil, Andre

    2014-01-01

    The 2D Wavelet-Transform Modulus Maxima (WTMM) method was used to detect microcalcifications (MC) in human breast tissue seen in mammograms and to characterize the fractal geometry of benign and malignant MC clusters. This was done in the context of a preliminary analysis of a small dataset, via a novel way to partition the wavelet-transform space-scale skeleton. For the first time, the estimated 3D fractal structure of a breast lesion was inferred by pairing the information from two separate 2D projected mammographic views of the same breast, i.e. the cranial-caudal (CC) and mediolateral-oblique (MLO) views. As a novelty, we define the “CC-MLO fractal dimension plot”, where a “fractal zone” and “Euclidean zones” (non-fractal) are defined. 118 images (59 cases, 25 malignant and 34 benign) obtained from a digital databank of mammograms with known radiologist diagnostics were analyzed to determine which cases would be plotted in the fractal zone and which cases would fall in the Euclidean zones. 92% of malignant breast lesions studied (23 out of 25 cases) were in the fractal zone while 88% of the benign lesions were in the Euclidean zones (30 out of 34 cases). Furthermore, a Bayesian statistical analysis shows that, with 95% credibility, the probability that fractal breast lesions are malignant is between 74% and 98%. Alternatively, with 95% credibility, the probability that Euclidean breast lesions are benign is between 76% and 96%. These results support the notion that the fractal structure of malignant tumors is more likely to be associated with an invasive behavior into the surrounding tissue compared to the less invasive, Euclidean structure of benign tumors. Finally, based on indirect 3D reconstructions from the 2D views, we conjecture that all breast tumors considered in this study, benign and malignant, fractal or Euclidean, restrict their growth to 2-dimensional manifolds within the breast tissue. PMID:25222610

  18. Wavelet-based 3D reconstruction of microcalcification clusters from two mammographic views: new evidence that fractal tumors are malignant and Euclidean tumors are benign.

    PubMed

    Batchelder, Kendra A; Tanenbaum, Aaron B; Albert, Seth; Guimond, Lyne; Kestener, Pierre; Arneodo, Alain; Khalil, Andre

    2014-01-01

    The 2D Wavelet-Transform Modulus Maxima (WTMM) method was used to detect microcalcifications (MC) in human breast tissue seen in mammograms and to characterize the fractal geometry of benign and malignant MC clusters. This was done in the context of a preliminary analysis of a small dataset, via a novel way to partition the wavelet-transform space-scale skeleton. For the first time, the estimated 3D fractal structure of a breast lesion was inferred by pairing the information from two separate 2D projected mammographic views of the same breast, i.e. the cranial-caudal (CC) and mediolateral-oblique (MLO) views. As a novelty, we define the "CC-MLO fractal dimension plot", where a "fractal zone" and "Euclidean zones" (non-fractal) are defined. 118 images (59 cases, 25 malignant and 34 benign) obtained from a digital databank of mammograms with known radiologist diagnostics were analyzed to determine which cases would be plotted in the fractal zone and which cases would fall in the Euclidean zones. 92% of malignant breast lesions studied (23 out of 25 cases) were in the fractal zone while 88% of the benign lesions were in the Euclidean zones (30 out of 34 cases). Furthermore, a Bayesian statistical analysis shows that, with 95% credibility, the probability that fractal breast lesions are malignant is between 74% and 98%. Alternatively, with 95% credibility, the probability that Euclidean breast lesions are benign is between 76% and 96%. These results support the notion that the fractal structure of malignant tumors is more likely to be associated with an invasive behavior into the surrounding tissue compared to the less invasive, Euclidean structure of benign tumors. Finally, based on indirect 3D reconstructions from the 2D views, we conjecture that all breast tumors considered in this study, benign and malignant, fractal or Euclidean, restrict their growth to 2-dimensional manifolds within the breast tissue.

  19. 3D weak lensing with spin wavelets on the ball

    NASA Astrophysics Data System (ADS)

    Leistedt, Boris; McEwen, Jason D.; Kitching, Thomas D.; Peiris, Hiranya V.

    2015-12-01

    We construct the spin flaglet transform, a wavelet transform to analyze spin signals in three dimensions. Spin flaglets can probe signal content localized simultaneously in space and frequency and, moreover, are separable so that their angular and radial properties can be controlled independently. They are particularly suited to analyzing cosmological observations such as the weak gravitational lensing of galaxies. Such observations have a unique 3D geometrical setting since they are natively made on the sky, have spin angular symmetries, and are extended in the radial direction by additional distance or redshift information. Flaglets are constructed in the harmonic space defined by the Fourier-Laguerre transform, previously defined for scalar functions and extended here to signals with spin symmetries. Thanks to various sampling theorems, both the Fourier-Laguerre and flaglet transforms are theoretically exact when applied to bandlimited signals. In other words, in numerical computations the only loss of information is due to the finite representation of floating point numbers. We develop a 3D framework relating the weak lensing power spectrum to covariances of flaglet coefficients. We suggest that the resulting novel flaglet weak lensing estimator offers a powerful alternative to common 2D and 3D approaches to accurately capture cosmological information. While standard weak lensing analyses focus on either real- or harmonic-space representations (i.e., correlation functions or Fourier-Bessel power spectra, respectively), a wavelet approach inherits the advantages of both techniques, where both complicated sky coverage and uncertainties associated with the physical modeling of small scales can be handled effectively. Our codes to compute the Fourier-Laguerre and flaglet transforms are made publicly available.

  20. CVS Decomposition of 3D Homogeneous Turbulence Using Orthogonal Wavelets

    NASA Technical Reports Server (NTRS)

    Farge, Marie; Schneider, Kai; Pellegrino, Giulio; Wray, A. A.; Rogallo, R. S.

    2000-01-01

    This paper compares the filtering used in Coherent Vortex Simulation (CVS) decomposition with an orthogonal wavelet basis, with the Proper Orthogonal Decomposition (POD) or Fourier filtering. Both methods are applied to a field of Direct Numerical Simulation (DNS) data of 3D forced homogeneous isotropic turbulence at microscale Reynolds number R(sub lambda) = 168. We show that, with only 3%N retained modes, CVS filtering separates the coherent vortex tubes from the incoherent background flow. The latter is structureless, has an equipartition energy spectrum, and has a Gaussian velocity probability distribution function (PDF) and an exponential vorticity PDF. On the other hand, the Fourier basis does not extract the coherent vortex tubes cleanly and leaves organized structures in the residual high wavenumber modes whose PDFs are stretched exponentials for both the velocity and the vorticity.

  1. Data compression studies for NOAA Hyperspectral Environmental Suite (HES) using 3D integer wavelet transforms with 3D set partitioning in hierarchical trees

    NASA Astrophysics Data System (ADS)

    Huang, Bormin; Huang, Hung-Lung; Chen, Hao; Ahuja, Alok; Baggett, Kevin; Schmit, Timothy J.; Heymann, Roger W.

    2004-02-01

    The next-generation NOAA/NESDIS GOES-R hyperspectral sounder, now referred to as the HES (Hyperspectral Environmental Suite), will have hyperspectral resolution (over one thousand channels with spectral widths on the order of 0.5 wavenumber) and high spatial resolution (less than 10 km). Hyperspectral sounder data is a particular class of data requiring high accuracy for useful retrieval of atmospheric temperature and moisture profiles, surface characteristics, cloud properties, and trace gas information. Hence compression of these data sets is better to be lossless or near lossless. Given the large volume of three-dimensional hyperspectral sounder data that will be generated by the HES instrument, the use of robust data compression techniques will be beneficial to data transfer and archive. In this paper, we study lossless data compression for the HES using 3D integer wavelet transforms via the lifting schemes. The wavelet coefficients are processed with the 3D set partitioning in hierarchical trees (SPIHT) scheme followed by context-based arithmetic coding. SPIHT provides better coding efficiency than Shapiro's original embedded zerotree wavelet (EZW) algorithm. We extend the 3D SPIHT scheme to take on any size of 3D satellite data, each of whose dimensions need not be divisible by 2N, where N is the levels of the wavelet decomposition being performed. The compression ratios of various kinds of wavelet transforms are presented along with a comparison with the JPEG2000 codec.

  2. Lossless data compression studies for NOAA hyperspectral environmental suite using 3D integer wavelet transforms with 3D embedded zerotree coding

    NASA Astrophysics Data System (ADS)

    Huang, Bormin; Huang, Hung-Lung; Chen, Hao; Ahuja, Alok; Baggett, Kevin; Schmit, Timothy J.; Heymann, Roger W.

    2003-09-01

    Hyperspectral sounder data is a particular class of data that requires high accuracy for useful retrieval of atmospheric temperature and moisture profiles, surface characteristics, cloud properties, and trace gas information. Therefore compression of these data sets is better to be lossless or near lossless. The next-generation NOAA/NESDIS GOES-R hyperspectral sounder, now referred to as the HES (Hyperspectral Environmental Suite), will have hyperspectral resolution (over one thousand channels with spectral widths on the order of 0.5 wavenumber) and high spatial resolution (less than 10 km). Given the large volume of three-dimensional hyperspectral sounder data that will be generated by the HES instrument, the use of robust data compression techniques will be beneficial to data transfer and archive. In this paper, we study lossless data compression for the HES using 3D integer wavelet transforms via the lifting schemes. The wavelet coefficients are then processed with the 3D embedded zerotree wavelet (EZW) algorithm followed by context-based arithmetic coding. We extend the 3D EZW scheme to take on any size of 3D satellite data, each of whose dimensions need not be divisible by 2N, where N is the levels of the wavelet decomposition being performed. The compression ratios of various kinds of wavelet transforms are presented along with a comparison with the JPEG2000 codec.

  3. 3-D Solid Texture Classification Using Locally-Oriented Wavelet Transforms.

    PubMed

    Dicente Cid, Yashin; Muller, Henning; Platon, Alexandra; Poletti, Pierre; Depeursinge, Adrien

    2017-02-06

    Many image acquisition techniques used in biomedical imaging, material analysis, and structural geology are capable of acquiring 3-D solid images. Computational analysis of these images is complex but necessary since it is difficult for humans to visualize and quantify their detailed 3-D content. One of the most common methods to analyze 3-D data is to characterize the volumetric texture patterns. Texture analysis generally consists of encoding the local organization of image scales and directions, which can be extremely diverse in 3-D. Current state-of-the- art techniques face many challenges when working with 3-D solid texture, where most approaches are not able to consistently characterize both scale and directional information. 3-D Riesz- wavelets can deal with both properties. One key property of Riesz filterbanks is steerability, which can be used to locally align the filters and compare textures with arbitrary (local) orientations. This paper proposes and compares three novel local alignment criteria for higher-order 3-D Riesz-wavelet transforms. The estimations of local texture orientations are based on higher- order extensions of regularized structure tensors. An experimental evaluation of the proposed methods for the classification of synthetic 3-D solid textures with alterations (such as rotations and noise) demonstrated the importance of local directional information for robust and accurate solid texture recognition. These alignment methods improved the accuracy of the unaligned Riesz descriptors up to 0.63, from 0.32 to 0.95 over 1 in the rotated data, which is better than all other techniques that are published and tested on the same database.

  4. Multiscale 3-D shape representation and segmentation using spherical wavelets.

    PubMed

    Nain, Delphine; Haker, Steven; Bobick, Aaron; Tannenbaum, Allen

    2007-04-01

    This paper presents a novel multiscale shape representation and segmentation algorithm based on the spherical wavelet transform. This work is motivated by the need to compactly and accurately encode variations at multiple scales in the shape representation in order to drive the segmentation and shape analysis of deep brain structures, such as the caudate nucleus or the hippocampus. Our proposed shape representation can be optimized to compactly encode shape variations in a population at the needed scale and spatial locations, enabling the construction of more descriptive, nonglobal, nonuniform shape probability priors to be included in the segmentation and shape analysis framework. In particular, this representation addresses the shortcomings of techniques that learn a global shape prior at a single scale of analysis and cannot represent fine, local variations in a population of shapes in the presence of a limited dataset. Specifically, our technique defines a multiscale parametric model of surfaces belonging to the same population using a compact set of spherical wavelets targeted to that population. We further refine the shape representation by separating into groups wavelet coefficients that describe independent global and/or local biological variations in the population, using spectral graph partitioning. We then learn a prior probability distribution induced over each group to explicitly encode these variations at different scales and spatial locations. Based on this representation, we derive a parametric active surface evolution using the multiscale prior coefficients as parameters for our optimization procedure to naturally include the prior for segmentation. Additionally, the optimization method can be applied in a coarse-to-fine manner. We apply our algorithm to two different brain structures, the caudate nucleus and the hippocampus, of interest in the study of schizophrenia. We show: 1) a reconstruction task of a test set to validate the expressiveness of

  5. Hyperspectral image compression: adapting SPIHT and EZW to anisotropic 3-D wavelet coding.

    PubMed

    Christophe, Emmanuel; Mailhes, Corinne; Duhamel, Pierre

    2008-12-01

    Hyperspectral images present some specific characteristics that should be used by an efficient compression system. In compression, wavelets have shown a good adaptability to a wide range of data, while being of reasonable complexity. Some wavelet-based compression algorithms have been successfully used for some hyperspectral space missions. This paper focuses on the optimization of a full wavelet compression system for hyperspectral images. Each step of the compression algorithm is studied and optimized. First, an algorithm to find the optimal 3-D wavelet decomposition in a rate-distortion sense is defined. Then, it is shown that a specific fixed decomposition has almost the same performance, while being more useful in terms of complexity issues. It is shown that this decomposition significantly improves the classical isotropic decomposition. One of the most useful properties of this fixed decomposition is that it allows the use of zero tree algorithms. Various tree structures, creating a relationship between coefficients, are compared. Two efficient compression methods based on zerotree coding (EZW and SPIHT) are adapted on this near-optimal decomposition with the best tree structure found. Performances are compared with the adaptation of JPEG 2000 for hyperspectral images on six different areas presenting different statistical properties.

  6. 3D Segmentation of Maxilla in Cone-beam Computed Tomography Imaging Using Base Invariant Wavelet Active Shape Model on Customized Two-manifold Topology

    PubMed Central

    Chang, Yu-Bing; Xia, James J.; Yuan, Peng; Kuo, Tai-Hong; Xiong, Zixiang; Gateno, Jaime; Zhou, Xiaobo

    2013-01-01

    Recent advances in cone-beam computed tomography (CBCT) have rapidly enabled widepsread applications of dentomaxillofacial imaging and orthodontic practices in the past decades due to its low radiation dose, high spatial resolution, and accessibility. However, low contrast resolution in CBCT image has become its major limitation in building skull models. Intensive hand-segmentation is usually required to reconstruct the skull models. One of the regions affected by this limitation the most is the thin bone images. This paper presents a novel segmentation approach based on wavelet density model (WDM) for a particular interest in the outer surface of anterior wall of maxilla. Nineteen CBCT datasets are used to conduct two experiments. This mode-based segmentation approach is validated and compared with three different segmentation approaches. The results show that the performance of this model-based segmentation approach is better than those of the other approaches. It can achieve 0.25 ± 0.2mm of surface error from ground truth of bone surface. PMID:23694914

  7. Comments on the paper 'A novel 3D wavelet-based filter forvisualizing features in noisy biological data', by Moss et al.

    SciTech Connect

    Luengo Hendriks, Cris L.; Knowles, David W.

    2006-02-04

    Moss et al.(2005) describe, in a recent paper, a filter thatthey use to detect lines. We noticed that the wavelet on which thisfilter is based is a difference of uniform filters. This filter is anapproximation to the second derivative operator, which is commonlyimplemented as the Laplace of Gaussian (or Marr-Hildreth) operator (Marr&Hildreth, 1980; Jahne, 2002), Figure 1. We have compared Moss'filter with 1) the Laplace of Gaussian operator, 2) an approximation ofthe Laplace of Gaussian using uniform filters, and 3) a few common noisereduction filters. The Laplace-like operators detect lines by suppressingimage features both larger and smaller than the filter size. The noisereduction filters only suppress image features smaller than the filtersize. By estimating the signal to noise ratio (SNR) and mean squaredifference (MSD) of the filtered results, we found that the filterproposed by Moss et al. does not outperform the Laplace of Gaussianoperator. We also found that for images with extreme noise content, linedetection filters perform better than the noise reduction filters whentrying to enhance line structures. In less extreme cases of noise, thestandard noise reduction filters perform significantly better than boththe Laplace of Gaussian and Moss' filter.

  8. Frames-Based Denoising in 3D Confocal Microscopy Imaging.

    PubMed

    Konstantinidis, Ioannis; Santamaria-Pang, Alberto; Kakadiaris, Ioannis

    2005-01-01

    In this paper, we propose a novel denoising method for 3D confocal microscopy data based on robust edge detection. Our approach relies on the construction of a non-separable frame system in 3D that incorporates the Sobel operator in dual spatial directions. This multidirectional set of digital filters is capable of robustly detecting edge information by ensemble thresholding of the filtered data. We demonstrate the application of our method to both synthetic and real confocal microscopy data by comparing it to denoising methods based on separable 3D wavelets and 3D median filtering, and report very encouraging results.

  9. The Wavelet Element Method. Part 2; Realization and Additional Features in 2D and 3D

    NASA Technical Reports Server (NTRS)

    Canuto, Claudio; Tabacco, Anita; Urban, Karsten

    1998-01-01

    The Wavelet Element Method (WEM) provides a construction of multiresolution systems and biorthogonal wavelets on fairly general domains. These are split into subdomains that are mapped to a single reference hypercube. Tensor products of scaling functions and wavelets defined on the unit interval are used on the reference domain. By introducing appropriate matching conditions across the interelement boundaries, a globally continuous biorthogonal wavelet basis on the general domain is obtained. This construction does not uniquely define the basis functions but rather leaves some freedom for fulfilling additional features. In this paper we detail the general construction principle of the WEM to the 1D, 2D and 3D cases. We address additional features such as symmetry, vanishing moments and minimal support of the wavelet functions in each particular dimension. The construction is illustrated by using biorthogonal spline wavelets on the interval.

  10. Lossless compression of 3D hyperspectral sounder data using the wavelet and Burrows-Wheeler transforms

    NASA Astrophysics Data System (ADS)

    Wei, Shih-Chieh; Huang, Bormin

    2004-10-01

    Hyperspectral sounder data is used for retrieval of useful geophysical parameters which promise better weather prediction. It features two characteristics. First it is huge in size with 2D spatial coverage and high spectral resolution in the infrared region. Second it allows low tolerance of noise and error in retrieving the geophysical parameters where a mathematically ill-posed problem is involved. Therefore compression is better to be lossless or near lossless for data transfer and archive. Meanwhile medical data from X-ray computerized tomography (CT) or magnetic resonance imaging (MRI) techniques also possesses similar characteristics. It provides motivation to apply lossless compression schemes for medical data to the hyperspectral sounder data. In this paper, we explore the use of a wavelet-based lossless data compression scheme for the 3D hyperspectral data which uses in sequence a forward difference scheme, an integer wavelet transform, a Burrows-Wheeler transform and an arithmetic coder. Compared to previous work, our approach is shown to outperform the CALIC and 3D EZW schemes.

  11. A parallel 3-D discrete wavelet transform architecture using pipelined lifting scheme approach for video coding

    NASA Astrophysics Data System (ADS)

    Hegde, Ganapathi; Vaya, Pukhraj

    2013-10-01

    This article presents a parallel architecture for 3-D discrete wavelet transform (3-DDWT). The proposed design is based on the 1-D pipelined lifting scheme. The architecture is fully scalable beyond the present coherent Daubechies filter bank (9, 7). This 3-DDWT architecture has advantages such as no group of pictures restriction and reduced memory referencing. It offers low power consumption, low latency and high throughput. The computing technique is based on the concept that lifting scheme minimises the storage requirement. The application specific integrated circuit implementation of the proposed architecture is done by synthesising it using 65 nm Taiwan Semiconductor Manufacturing Company standard cell library. It offers a speed of 486 MHz with a power consumption of 2.56 mW. This architecture is suitable for real-time video compression even with large frame dimensions.

  12. Multi-resolution Gabor wavelet feature extraction for needle detection in 3D ultrasound

    NASA Astrophysics Data System (ADS)

    Pourtaherian, Arash; Zinger, Svitlana; Mihajlovic, Nenad; de With, Peter H. N.; Huang, Jinfeng; Ng, Gary C.; Korsten, Hendrikus H. M.

    2015-12-01

    Ultrasound imaging is employed for needle guidance in various minimally invasive procedures such as biopsy guidance, regional anesthesia and brachytherapy. Unfortunately, a needle guidance using 2D ultrasound is very challenging, due to a poor needle visibility and a limited field of view. Nowadays, 3D ultrasound systems are available and more widely used. Consequently, with an appropriate 3D image-based needle detection technique, needle guidance and interventions may significantly be improved and simplified. In this paper, we present a multi-resolution Gabor transformation for an automated and reliable extraction of the needle-like structures in a 3D ultrasound volume. We study and identify the best combination of the Gabor wavelet frequencies. High precision in detecting the needle voxels leads to a robust and accurate localization of the needle for the intervention support. Evaluation in several ex-vivo cases shows that the multi-resolution analysis significantly improves the precision of the needle voxel detection from 0.23 to 0.32 at a high recall rate of 0.75 (gain 40%), where a better robustness and confidence were confirmed in the practical experiments.

  13. Crowdsourcing Based 3d Modeling

    NASA Astrophysics Data System (ADS)

    Somogyi, A.; Barsi, A.; Molnar, B.; Lovas, T.

    2016-06-01

    Web-based photo albums that support organizing and viewing the users' images are widely used. These services provide a convenient solution for storing, editing and sharing images. In many cases, the users attach geotags to the images in order to enable using them e.g. in location based applications on social networks. Our paper discusses a procedure that collects open access images from a site frequently visited by tourists. Geotagged pictures showing the image of a sight or tourist attraction are selected and processed in photogrammetric processing software that produces the 3D model of the captured object. For the particular investigation we selected three attractions in Budapest. To assess the geometrical accuracy, we used laser scanner and DSLR as well as smart phone photography to derive reference values to enable verifying the spatial model obtained from the web-album images. The investigation shows how detailed and accurate models could be derived applying photogrammetric processing software, simply by using images of the community, without visiting the site.

  14. Combining a wavelet transform with a channelized Hotelling observer for tumor detection in 3D PET oncology imaging

    NASA Astrophysics Data System (ADS)

    Lartizien, Carole; Tomei, Sandrine; Maxim, Voichita; Odet, Christophe

    2007-03-01

    This study evaluates new observer models for 3D whole-body Positron Emission Tomography (PET) imaging based on a wavelet sub-band decomposition and compares them with the classical constant-Q CHO model. Our final goal is to develop an original method that performs guided detection of abnormal activity foci in PET oncology imaging based on these new observer models. This computer-aided diagnostic method would highly benefit to clinicians for diagnostic purpose and to biologists for massive screening of rodents populations in molecular imaging. Method: We have previously shown good correlation of the channelized Hotelling observer (CHO) using a constant-Q model with human observer performance for 3D PET oncology imaging. We propose an alternate method based on combining a CHO observer with a wavelet sub-band decomposition of the image and we compare it to the standard CHO implementation. This method performs an undecimated transform using a biorthogonal B-spline 4/4 wavelet basis to extract the features set for input to the Hotelling observer. This work is based on simulated 3D PET images of an extended MCAT phantom with randomly located lesions. We compare three evaluation criteria: classification performance using the signal-to-noise ratio (SNR), computation efficiency and visual quality of the derived 3D maps of the decision variable λ. The SNR is estimated on a series of test images for a variable number of training images for both observers. Results: Results show that the maximum SNR is higher with the constant-Q CHO observer, especially for targets located in the liver, and that it is reached with a smaller number of training images. However, preliminary analysis indicates that the visual quality of the 3D maps of the decision variable λ is higher with the wavelet-based CHO and the computation time to derive a 3D λ-map is about 350 times shorter than for the standard CHO. This suggests that the wavelet-CHO observer is a good candidate for use in our guided

  15. A new structure of 3D dual-tree discrete wavelet transforms and applications to video denoising and coding

    NASA Astrophysics Data System (ADS)

    Shi, Fei; Wang, Beibei; Selesnick, Ivan W.; Wang, Yao

    2006-01-01

    This paper introduces an anisotropic decomposition structure of a recently introduced 3-D dual-tree discrete wavelet transform (DDWT), and explores the applications for video denoising and coding. The 3-D DDWT is an attractive video representation because it isolates motion along different directions in separate subbands, and thus leads to sparse video decompositions. Our previous investigation shows that the 3-D DDWT, compared to the standard discrete wavelet transform (DWT), complies better with the statistical models based on sparse presumptions, and gives better visual and numerical results when used for statistical denoising algorithms. Our research on video compression also shows that even with 4:1 redundancy, the 3-D DDWT needs fewer coefficients to achieve the same coding quality (in PSNR) by applying the iterative projection-based noise shaping scheme proposed by Kingsbury. The proposed anisotropic DDWT extends the superiority of isotropic DDWT with more directional subbands without adding to the redundancy. Unlike the original 3-D DDWT which applies dyadic decomposition along all three directions and produces isotropic frequency spacing, it has a non-uniform tiling of the frequency space. By applying this structure, we can improve the denoising results, and the number of significant coefficients can be reduced further, which is beneficial for video coding.

  16. Laser Based 3D Volumetric Display System

    DTIC Science & Technology

    1993-03-01

    Literature, Costa Mesa, CA July 1983. 3. "A Real Time Autostereoscopic Multiplanar 3D Display System", Rodney Don Williams, Felix Garcia, Jr., Texas...8217 .- NUMBERS LASER BASED 3D VOLUMETRIC DISPLAY SYSTEM PR: CD13 0. AUTHOR(S) PE: N/AWIU: DN303151 P. Soltan, J. Trias, W. Robinson, W. Dahlke 7...laser generated 3D volumetric images on a rotating double helix, (where the 3D displays are computer controlled for group viewing with the naked eye

  17. Comparison of 2D and 3D wavelet features for TLE lateralization

    NASA Astrophysics Data System (ADS)

    Jafari-Khouzani, Kourosh; Soltanian-Zadeh, Hamid; Elisevich, Kost; Patel, Suresh

    2004-04-01

    Intensity and volume features of the hippocampus from MR images of the brain are known to be useful in detecting the abnormality and consequently candidacy of the hippocampus for temporal lobe epilepsy surgery. However, currently, intracranial EEG exams are required to determine the abnormal hippocampus. These exams are lengthy, painful and costly. The aim of this study is to evaluate texture characteristics of the hippocampi from MR images to help physicians determine the candidate hippocampus for surgery. We studied the MR images of 20 epileptic patients. Intracranial EEG results as well as surgery outcome were used as gold standard. The hippocampi were manually segmented by an expert from T1-weighted MR images. Then the segmented regions were mapped on the corresponding FLAIR images for texture analysis. We calculate the average energy features from 2D wavelet transform of each slice of hippocampus as well as the energy features produced by 3D wavelet transform of the whole hippocampus volume. The 2D wavelet transform is calculated both from the original slices as well as from the slices perpendicular to the principal axis of the hippocampus. In order to calculate the 3D wavelet transform we first rotate each hippocampus to fit it in a rectangular prism and then fill the empty area by extrapolating the intensity values. We combine the resulting features with volume feature and compare their ability to distinguish between normal and abnormal hippocampi using linear classifier and fuzzy c-means clustering algorithm. Experimental results show that the texture features can correctly classify the hippocampi.

  18. Nonlaser-based 3D surface imaging

    SciTech Connect

    Lu, Shin-yee; Johnson, R.K.; Sherwood, R.J.

    1994-11-15

    3D surface imaging refers to methods that generate a 3D surface representation of objects of a scene under viewing. Laser-based 3D surface imaging systems are commonly used in manufacturing, robotics and biomedical research. Although laser-based systems provide satisfactory solutions for most applications, there are situations where non laser-based approaches are preferred. The issues that make alternative methods sometimes more attractive are: (1) real-time data capturing, (2) eye-safety, (3) portability, and (4) work distance. The focus of this presentation is on generating a 3D surface from multiple 2D projected images using CCD cameras, without a laser light source. Two methods are presented: stereo vision and depth-from-focus. Their applications are described.

  19. An Automatic 3D Facial Landmarking Algorithm Using 2D Gabor Wavelets.

    PubMed

    de Jong, Markus A; Wollstein, Andreas; Ruff, Clifford; Dunaway, David; Hysi, Pirro; Spector, Tim; Fan Liu; Niessen, Wiro; Koudstaal, Maarten J; Kayser, Manfred; Wolvius, Eppo B; Bohringer, Stefan

    2016-02-01

    In this paper, we present a novel approach to automatic 3D facial landmarking using 2D Gabor wavelets. Our algorithm considers the face to be a surface and uses map projections to derive 2D features from raw data. Extracted features include texture, relief map, and transformations thereof. We extend an established 2D landmarking method for simultaneous evaluation of these data. The method is validated by performing landmarking experiments on two data sets using 21 landmarks and compared with an active shape model implementation. On average, landmarking error for our method was 1.9 mm, whereas the active shape model resulted in an average landmarking error of 2.3 mm. A second study investigating facial shape heritability in related individuals concludes that automatic landmarking is on par with manual landmarking for some landmarks. Our algorithm can be trained in 30 min to automatically landmark 3D facial data sets of any size, and allows for fast and robust landmarking of 3D faces.

  20. Model-based 3D SAR reconstruction

    NASA Astrophysics Data System (ADS)

    Knight, Chad; Gunther, Jake; Moon, Todd

    2014-06-01

    Three dimensional scene reconstruction with synthetic aperture radar (SAR) is desirable for target recognition and improved scene interpretability. The vertical aperture, which is critical to reconstruct 3D SAR scenes, is almost always sparsely sampled due to practical limitations, which creates an underdetermined problem. This papers explores 3D scene reconstruction using a convex model-based approach. The approach developed is demonstrated on 3D scenes, but can be extended to SAR reconstruction of sparsely sampled signals in the spatial and, or, frequency domains. The model-based approach enables knowledge-aided image formation (KAIF) by incorporating spatial, aspect, and sparsity magnitude terms into the image reconstruction. The incorporation of these terms, which are based on prior scene knowledge, will demonstrate improved results compared to traditional image formation algorithms. The SAR image formation problem is formulated as a second order cone program (SOCP) and the results are demonstrated on 3D scenes using simulated data and data from the GOTCHA data collect.1 The model-based results are contrasted against traditional backprojected images.

  1. Wavelet-Based Grid Generation

    NASA Technical Reports Server (NTRS)

    Jameson, Leland

    1996-01-01

    Wavelets can provide a basis set in which the basis functions are constructed by dilating and translating a fixed function known as the mother wavelet. The mother wavelet can be seen as a high pass filter in the frequency domain. The process of dilating and expanding this high-pass filter can be seen as altering the frequency range that is 'passed' or detected. The process of translation moves this high-pass filter throughout the domain, thereby providing a mechanism to detect the frequencies or scales of information at every location. This is exactly the type of information that is needed for effective grid generation. This paper provides motivation to use wavelets for grid generation in addition to providing the final product: source code for wavelet-based grid generation.

  2. Biorthogonal wavelet-based method of moments for electromagnetic scattering

    NASA Astrophysics Data System (ADS)

    Zhang, Qinke

    Wavelet analysis is a technique developed in recent years in mathematics and has found usefulness in signal processing and many other engineering areas. The practical use of wavelets for the solution of partial differential and integral equations in computational electromagnetics has been investigated in this dissertation, with the emphasis on development of biorthogonal wavelet based method of moments for the solution of electric and magnetic field integral equations. The fundamentals and numerical analysis aspects of wavelet theory have been studied. In particular, a family of compactly supported biorthogonal spline wavelet bases on the n-cube (0,1) n has been studied in detail. The wavelet bases were used in this work as a building block to construct biorthogonal wavelet bases on general domain geometry. A specific and practical way of adapting the wavelet bases to certain n- dimensional blocks or elements is proposed based on the domain decomposition and local transformation techniques used in traditional finite element methods and computer aided graphics. The element, with the biorthogonal wavelet base embedded in it, is called a wavelet element in this work. The physical domains which can be treated with this method include general curves, surfaces in 2D and 3D, and 3D volume domains. A two-step mapping is proposed for the purpose of taking full advantage of the zero-moments of wavelets. The wavelet element approach appears to offer several important advantages. It avoids the need of generating very complicated meshes required in traditional finite element based methods, and makes the adaptive analysis easy to implement. A specific implementation procedure for performing adaptive analysis is proposed. The proposed biorthogonal wavelet based method of moments (BWMoM) has been implemented by using object-oriented programming techniques. The main computational issues have been detailed, discussed, and implemented in the whole package. Numerical examples show

  3. Three-dimensional compression scheme based on wavelet transform

    NASA Astrophysics Data System (ADS)

    Yang, Wu; Xu, Hui; Liao, Mengyang

    1999-03-01

    In this paper, a 3D compression method based on separable wavelet transform is discussed in detail. The most commonly used digital modalities generate multiple slices in a single examination, which are normally anatomically or physiologically correlated to each other. 3D wavelet compression methods can achieve more efficient compression by exploring the correlation between slices. The first step is based on a separable 3D wavelet transform. Considering the difference between pixel distances within a slice and those between slices, one biorthogonal Antoninin filter bank is applied within 2D slices and a second biorthogonal Villa4 filter bank on the slice direction. Then, S+P transform is applied in the low-resolution wavelet components and an optimal quantizer is presented after analysis of the quantization noise. We use an optimal bit allocation algorithm, which, instead of eliminating the coefficients of high-resolution components in smooth areas, minimizes the system reconstruction distortion at a given bit-rate. Finally, to remain high coding efficiency and adapt to different properties of each component, a comprehensive entropy coding method is proposed, in which arithmetic coding method is applied in high-resolution components and adaptive Huffman coding method in low-resolution components. Our experimental results are evaluated by several image measures and our 3D wavelet compression scheme is proved to be more efficient than 2D wavelet compression.

  4. 3-D model-based vehicle tracking.

    PubMed

    Lou, Jianguang; Tan, Tieniu; Hu, Weiming; Yang, Hao; Maybank, Steven J

    2005-10-01

    This paper aims at tracking vehicles from monocular intensity image sequences and presents an efficient and robust approach to three-dimensional (3-D) model-based vehicle tracking. Under the weak perspective assumption and the ground-plane constraint, the movements of model projection in the two-dimensional image plane can be decomposed into two motions: translation and rotation. They are the results of the corresponding movements of 3-D translation on the ground plane (GP) and rotation around the normal of the GP, which can be determined separately. A new metric based on point-to-line segment distance is proposed to evaluate the similarity between an image region and an instantiation of a 3-D vehicle model under a given pose. Based on this, we provide an efficient pose refinement method to refine the vehicle's pose parameters. An improved EKF is also proposed to track and to predict vehicle motion with a precise kinematics model. Experimental results with both indoor and outdoor data show that the algorithm obtains desirable performance even under severe occlusion and clutter.

  5. 3D profile measurements of objects by using zero order Generalized Morse Wavelet

    NASA Astrophysics Data System (ADS)

    Kocahan, Özlem; Durmuş, ćaǧla; Elmas, Merve Naz; Coşkun, Emre; Tiryaki, Erhan; Özder, Serhat

    2017-02-01

    Generalized Morse wavelets are proposed to evaluate the phase information from projected fringe pattern with the spatial carrier frequency in the x direction. The height profile of the object is determined through the phase change distribution by using the phase of the continuous wavelet transform. The phase distribution is extracted from the optical fringe pattern choosing zero order Generalized Morse Wavelet (GMW) as a mother wavelet. In this study, standard fringe projection technique is used for obtaining images. Experimental results for the GMW phase method are compared with the results of Morlet and Paul wavelet transform.

  6. REGULARIZED 3D FUNCTIONAL REGRESSION FOR BRAIN IMAGE DATA VIA HAAR WAVELETS.

    PubMed

    Wang, Xuejing; Nan, Bin; Zhu, Ji; Koeppe, Robert

    2014-06-01

    The primary motivation and application in this article come from brain imaging studies on cognitive impairment in elderly subjects with brain disorders. We propose a regularized Haar wavelet-based approach for the analysis of three-dimensional brain image data in the framework of functional data analysis, which automatically takes into account the spatial information among neighboring voxels. We conduct extensive simulation studies to evaluate the prediction performance of the proposed approach and its ability to identify related regions to the outcome of interest, with the underlying assumption that only few relatively small subregions are truly predictive of the outcome of interest. We then apply the proposed approach to searching for brain subregions that are associated with cognition using PET images of patients with Alzheimer's disease, patients with mild cognitive impairment, and normal controls.

  7. Scalable 3D GIS environment managed by 3D-XML-based modeling

    NASA Astrophysics Data System (ADS)

    Shi, Beiqi; Rui, Jianxun; Chen, Neng

    2008-10-01

    Nowadays, the namely 3D GIS technologies become a key factor in establishing and maintaining large-scale 3D geoinformation services. However, with the rapidly increasing size and complexity of the 3D models being acquired, a pressing needed for suitable data management solutions has become apparent. This paper outlines that storage and exchange of geospatial data between databases and different front ends like 3D models, GIS or internet browsers require a standardized format which is capable to represent instances of 3D GIS models, to minimize loss of information during data transfer and to reduce interface development efforts. After a review of previous methods for spatial 3D data management, a universal lightweight XML-based format for quick and easy sharing of 3D GIS data is presented. 3D data management based on XML is a solution meeting the requirements as stated, which can provide an efficient means for opening a new standard way to create an arbitrary data structure and share it over the Internet. To manage reality-based 3D models, this paper uses 3DXML produced by Dassault Systemes. 3DXML uses opening XML schemas to communicate product geometry, structure and graphical display properties. It can be read, written and enriched by standard tools; and allows users to add extensions based on their own specific requirements. The paper concludes with the presentation of projects from application areas which will benefit from the functionality presented above.

  8. 3D scene reconstruction based on 3D laser point cloud combining UAV images

    NASA Astrophysics Data System (ADS)

    Liu, Huiyun; Yan, Yangyang; Zhang, Xitong; Wu, Zhenzhen

    2016-03-01

    It is a big challenge capturing and modeling 3D information of the built environment. A number of techniques and technologies are now in use. These include GPS, and photogrammetric application and also remote sensing applications. The experiment uses multi-source data fusion technology for 3D scene reconstruction based on the principle of 3D laser scanning technology, which uses the laser point cloud data as the basis and Digital Ortho-photo Map as an auxiliary, uses 3DsMAX software as a basic tool for building three-dimensional scene reconstruction. The article includes data acquisition, data preprocessing, 3D scene construction. The results show that the 3D scene has better truthfulness, and the accuracy of the scene meet the need of 3D scene construction.

  9. Terrestrial and Aerial Laser Scanning Data Integration Using Wavelet Analysis for the Purpose of 3D Building Modeling

    PubMed Central

    Kedzierski, Michal; Fryskowska, Anna

    2014-01-01

    Visualization techniques have been greatly developed in the past few years. Three-dimensional models based on satellite and aerial imagery are now being enhanced by models generated using Aerial Laser Scanning (ALS) data. The most modern of such scanning systems have the ability to acquire over 50 points per square meter and to register a multiple echo, which allows the reconstruction of the terrain together with the terrain cover. However, ALS data accuracy is less than 10 cm and the data is often incomplete: there is no information about ground level (in most scanning systems), and often around the facade or structures which have been covered by other structures. However, Terrestrial Laser Scanning (TLS) not only acquires higher accuracy data (1–5 cm) but is also capable of registering those elements which are incomplete or not visible using ALS methods (facades, complicated structures, interiors, etc.). Therefore, to generate a complete 3D model of a building in high Level of Details, integration of TLS and ALS data is necessary. This paper presents the wavelet-based method of processing and integrating data from ALS and TLS. Methods of choosing tie points to combine point clouds in different datum will be analyzed. PMID:25004157

  10. Terrestrial and aerial laser scanning data integration using wavelet analysis for the purpose of 3D building modeling.

    PubMed

    Kedzierski, Michal; Fryskowska, Anna

    2014-07-07

    Visualization techniques have been greatly developed in the past few years. Three-dimensional models based on satellite and aerial imagery are now being enhanced by models generated using Aerial Laser Scanning (ALS) data. The most modern of such scanning systems have the ability to acquire over 50 points per square meter and to register a multiple echo, which allows the reconstruction of the terrain together with the terrain cover. However, ALS data accuracy is less than 10 cm and the data is often incomplete: there is no information about ground level (in most scanning systems), and often around the facade or structures which have been covered by other structures. However, Terrestrial Laser Scanning (TLS) not only acquires higher accuracy data (1-5 cm) but is also capable of registering those elements which are incomplete or not visible using ALS methods (facades, complicated structures, interiors, etc.). Therefore, to generate a complete 3D model of a building in high Level of Details, integration of TLS and ALS data is necessary. This paper presents the wavelet-based method of processing and integrating data from ALS and TLS. Methods of choosing tie points to combine point clouds in different datum will be analyzed.

  11. Combining 2D wavelet edge highlighting and 3D thresholding for lung segmentation in thin-slice CT.

    PubMed

    Korfiatis, P; Skiadopoulos, S; Sakellaropoulos, P; Kalogeropoulou, C; Costaridou, L

    2007-12-01

    The first step in lung analysis by CT is the identification of the lung border. To deal with the increased number of sections per scan in thin-slice multidetector CT, it has been crucial to develop accurate and automated lung segmentation algorithms. In this study, an automated method for lung segmentation of thin-slice CT data is presented. The method exploits the advantages of a two-dimensional wavelet edge-highlighting step in lung border delineation. Lung volume segmentation is achieved with three-dimensional (3D) grey level thresholding, using a minimum error technique. 3D thresholding, combined with the wavelet pre-processing step, successfully deals with lung border segmentation challenges, such as anterior or posterior junction lines and juxtapleural nodules. Finally, to deal with mediastinum border under-segmentation, 3D morphological closing with a spherical structural element is applied. The performance of the proposed method is quantitatively assessed on a dataset originating from the Lung Imaging Database Consortium (LIDC) by comparing automatically derived borders with the manually traced ones. Segmentation performance, averaged over left and right lung volumes, for lung volume overlap is 0.983+/-0.008, whereas for shape differentiation in terms of mean distance it is 0.770+/-0.251 mm (root mean square distance is 0.520+/-0.008 mm; maximum distance is 3.327+/-1.637 mm). The effect of the wavelet pre-processing step was assessed by comparing the proposed method with the 3D thresholding technique (applied on original volume data). This yielded statistically significant differences for all segmentation metrics (p<0.01). Results demonstrate an accurate method that could be used as a first step in computer lung analysis by CT.

  12. Wavelet Features Based Fingerprint Verification

    NASA Astrophysics Data System (ADS)

    Bagadi, Shweta U.; Thalange, Asha V.; Jain, Giridhar P.

    2010-11-01

    In this work; we present a automatic fingerprint identification system based on Level 3 features. Systems based only on minutiae features do not perform well for poor quality images. In practice, we often encounter extremely dry, wet fingerprint images with cuts, warts, etc. Due to such fingerprints, minutiae based systems show poor performance for real time authentication applications. To alleviate the problem of poor quality fingerprints, and to improve overall performance of the system, this paper proposes fingerprint verification based on wavelet statistical features & co-occurrence matrix features. The features include mean, standard deviation, energy, entropy, contrast, local homogeneity, cluster shade, cluster prominence, Information measure of correlation. In this method, matching can be done between the input image and the stored template without exhaustive search using the extracted feature. The wavelet transform based approach is better than the existing minutiae based method and it takes less response time and hence suitable for on-line verification, with high accuracy.

  13. The 3D visualization technology research of submarine pipeline based Horde3D GameEngine

    NASA Astrophysics Data System (ADS)

    Yao, Guanghui; Ma, Xiushui; Chen, Genlang; Ye, Lingjian

    2013-10-01

    With the development of 3D display and virtual reality technology, its application gets more and more widespread. This paper applies 3D display technology to the monitoring of submarine pipeline. We reconstruct the submarine pipeline and its surrounding submarine terrain in computer using Horde3D graphics rendering engine on the foundation database "submarine pipeline and relative landforms landscape synthesis database" so as to display the virtual scene of submarine pipeline based virtual reality and show the relevant data collected from the monitoring of submarine pipeline.

  14. Background Subtraction Based on Three-Dimensional Discrete Wavelet Transform.

    PubMed

    Han, Guang; Wang, Jinkuan; Cai, Xi

    2016-03-30

    Background subtraction without a separate training phase has become a critical task, because a sufficiently long and clean training sequence is usually unavailable, and people generally thirst for immediate detection results from the first frame of a video. Without a training phase, we propose a background subtraction method based on three-dimensional (3D) discrete wavelet transform (DWT). Static backgrounds with few variations along the time axis are characterized by intensity temporal consistency in the 3D space-time domain and, hence, correspond to low-frequency components in the 3D frequency domain. Enlightened by this, we eliminate low-frequency components that correspond to static backgrounds using the 3D DWT in order to extract moving objects. Owing to the multiscale analysis property of the 3D DWT, the elimination of low-frequency components in sub-bands of the 3D DWT is equivalent to performing a pyramidal 3D filter. This 3D filter brings advantages to our method in reserving the inner parts of detected objects and reducing the ringing around object boundaries. Moreover, we make use of wavelet shrinkage to remove disturbance of intensity temporal consistency and introduce an adaptive threshold based on the entropy of the histogram to obtain optimal detection results. Experimental results show that our method works effectively in situations lacking training opportunities and outperforms several popular techniques.

  15. Background Subtraction Based on Three-Dimensional Discrete Wavelet Transform

    PubMed Central

    Han, Guang; Wang, Jinkuan; Cai, Xi

    2016-01-01

    Background subtraction without a separate training phase has become a critical task, because a sufficiently long and clean training sequence is usually unavailable, and people generally thirst for immediate detection results from the first frame of a video. Without a training phase, we propose a background subtraction method based on three-dimensional (3D) discrete wavelet transform (DWT). Static backgrounds with few variations along the time axis are characterized by intensity temporal consistency in the 3D space-time domain and, hence, correspond to low-frequency components in the 3D frequency domain. Enlightened by this, we eliminate low-frequency components that correspond to static backgrounds using the 3D DWT in order to extract moving objects. Owing to the multiscale analysis property of the 3D DWT, the elimination of low-frequency components in sub-bands of the 3D DWT is equivalent to performing a pyramidal 3D filter. This 3D filter brings advantages to our method in reserving the inner parts of detected objects and reducing the ringing around object boundaries. Moreover, we make use of wavelet shrinkage to remove disturbance of intensity temporal consistency and introduce an adaptive threshold based on the entropy of the histogram to obtain optimal detection results. Experimental results show that our method works effectively in situations lacking training opportunities and outperforms several popular techniques. PMID:27043570

  16. Wavelets based on Hermite cubic splines

    NASA Astrophysics Data System (ADS)

    Cvejnová, Daniela; Černá, Dana; Finěk, Václav

    2016-06-01

    In 2000, W. Dahmen et al. designed biorthogonal multi-wavelets adapted to the interval [0,1] on the basis of Hermite cubic splines. In recent years, several more simple constructions of wavelet bases based on Hermite cubic splines were proposed. We focus here on wavelet bases with respect to which both the mass and stiffness matrices are sparse in the sense that the number of nonzero elements in any column is bounded by a constant. Then, a matrix-vector multiplication in adaptive wavelet methods can be performed exactly with linear complexity for any second order differential equation with constant coefficients. In this contribution, we shortly review these constructions and propose a new wavelet which leads to improved Riesz constants. Wavelets have four vanishing wavelet moments.

  17. Pattern based 3D image Steganography

    NASA Astrophysics Data System (ADS)

    Thiyagarajan, P.; Natarajan, V.; Aghila, G.; Prasanna Venkatesan, V.; Anitha, R.

    2013-03-01

    This paper proposes a new high capacity Steganographic scheme using 3D geometric models. The novel algorithm re-triangulates a part of a triangle mesh and embeds the secret information into newly added position of triangle meshes. Up to nine bits of secret data can be embedded into vertices of a triangle without causing any changes in the visual quality and the geometric properties of the cover image. Experimental results show that the proposed algorithm is secure, with high capacity and low distortion rate. Our algorithm also resists against uniform affine transformations such as cropping, rotation and scaling. Also, the performance of the method is compared with other existing 3D Steganography algorithms. [Figure not available: see fulltext.

  18. Principal square root of 3-subdivision-based biorthogonal wavelets.

    PubMed

    Wang, Huawei; Qin, Kaihuai; Sun, Hanqiu

    2007-01-01

    A new efficient biorthogonal wavelet analysis based on the principal square root of subdivision is proposed in the paper by using the lifting scheme. Since the principal square root of subdivision is of the slowest topological refinement among the traditional triangular subdivisions, the multiresolution analysis based on the principal square root of subdivision is more balanced than the existing wavelet analyses on triangular meshes, and accordingly offers more levels of detail for processing polygonal models. In order to optimize the multiresolution analysis process, the new wavelets, no matter whether they are interior or on boundaries, are orthogonalized with the local scaling functions based on a discrete inner product with subdivision masks. Because the wavelet analysis and synthesis algorithms are actually composed of a series of local lifting operations, they can be performed in linear time. The experiments demonstrate the efficiency and stability of the wavelet analysis for both closed and open triangular meshes with principal square root of subdivision connectivity. The principal square root of -subdivision-based biorthogonal wavelets can be used in many applications such as progressive transmission, shape approximation, multiresolution editing and rendering of 3D geometric models.

  19. Reconstruction and 3D visualisation based on objective real 3D based documentation.

    PubMed

    Bolliger, Michael J; Buck, Ursula; Thali, Michael J; Bolliger, Stephan A

    2012-09-01

    Reconstructions based directly upon forensic evidence alone are called primary information. Historically this consists of documentation of findings by verbal protocols, photographs and other visual means. Currently modern imaging techniques such as 3D surface scanning and radiological methods (computer tomography, magnetic resonance imaging) are also applied. Secondary interpretation is based on facts and the examiner's experience. Usually such reconstructive expertises are given in written form, and are often enhanced by sketches. However, narrative interpretations can, especially in complex courses of action, be difficult to present and can be misunderstood. In this report we demonstrate the use of graphic reconstruction of secondary interpretation with supporting pictorial evidence, applying digital visualisation (using 'Poser') or scientific animation (using '3D Studio Max', 'Maya') and present methods of clearly distinguishing between factual documentation and examiners' interpretation based on three cases. The first case involved a pedestrian who was initially struck by a car on a motorway and was then run over by a second car. The second case involved a suicidal gunshot to the head with a rifle, in which the trigger was pushed with a rod. The third case dealt with a collision between two motorcycles. Pictorial reconstruction of the secondary interpretation of these cases has several advantages. The images enable an immediate overview, give rise to enhanced clarity, and compel the examiner to look at all details if he or she is to create a complete image.

  20. Wavelet-based denoising using local Laplace prior

    NASA Astrophysics Data System (ADS)

    Rabbani, Hossein; Vafadust, Mansur; Selesnick, Ivan

    2007-09-01

    Although wavelet-based image denoising is a powerful tool for image processing applications, relatively few publications have addressed so far wavelet-based video denoising. The main reason is that the standard 3-D data transforms do not provide useful representations with good energy compaction property, for most video data. For example, the multi-dimensional standard separable discrete wavelet transform (M-D DWT) mixes orientations and motions in its subbands, and produces the checkerboard artifacts. So, instead of M-D DWT, usually oriented transforms suchas multi-dimensional complex wavelet transform (M-D DCWT) are proposed for video processing. In this paper we use a Laplace distribution with local variance to model the statistical properties of noise-free wavelet coefficients. This distribution is able to simultaneously model the heavy-tailed and intrascale dependency properties of wavelets. Using this model, simple shrinkage functions are obtained employing maximum a posteriori (MAP) and minimum mean squared error (MMSE) estimators. These shrinkage functions are proposed for video denoising in DCWT domain. The simulation results shows that this simple denoising method has impressive performance visually and quantitatively.

  1. Improved l1-SPIRiT using 3D walsh transform-based sparsity basis.

    PubMed

    Feng, Zhen; Liu, Feng; Jiang, Mingfeng; Crozier, Stuart; Guo, He; Wang, Yuxin

    2014-09-01

    l1-SPIRiT is a fast magnetic resonance imaging (MRI) method which combines parallel imaging (PI) with compressed sensing (CS) by performing a joint l1-norm and l2-norm optimization procedure. The original l1-SPIRiT method uses two-dimensional (2D) Wavelet transform to exploit the intra-coil data redundancies and a joint sparsity model to exploit the inter-coil data redundancies. In this work, we propose to stack all the coil images into a three-dimensional (3D) matrix, and then a novel 3D Walsh transform-based sparsity basis is applied to simultaneously reduce the intra-coil and inter-coil data redundancies. Both the 2D Wavelet transform-based and the proposed 3D Walsh transform-based sparsity bases were investigated in the l1-SPIRiT method. The experimental results show that the proposed 3D Walsh transform-based l1-SPIRiT method outperformed the original l1-SPIRiT in terms of image quality and computational efficiency.

  2. 3D printing optical watermark algorithms based on the combination of DWT and Fresnel transformation

    NASA Astrophysics Data System (ADS)

    Hu, Qi; Duan, Jin; Zhai, Di; Wang, LiNing

    2016-10-01

    With the continuous development of industrialization, 3D printing technology steps into individuals' lives gradually, however, the consequential security issue has become the urgent problem which is imminent. This paper proposes the 3D printing optical watermark algorithms based on the combination of DWT and Fresnel transformation and utilizes authorized key to restrict 3D model printing's permissions. Firstly, algorithms put 3D model into affine transform, and take the distance from the center of gravity to the vertex of 3D object in order to generate a one-dimensional discrete signal; then make this signal into wavelet transform and put the transformed coefficient into Fresnel transformation. Use math model to embed watermark information into it and finally generate 3D digital model with watermarking. This paper adopts VC++.NET and DIRECTX 9.0 SDK for combined developing and testing, and the results show that in fixed affine space, achieve the robustness in translation, revolving and proportion transforms of 3D model and better watermark-invisibility. The security and authorization of 3D model have been protected effectively.

  3. 3D multifocus astigmatism and compressed sensing (3D MACS) based superresolution reconstruction

    PubMed Central

    Huang, Jiaqing; Sun, Mingzhai; Gumpper, Kristyn; Chi, Yuejie; Ma, Jianjie

    2015-01-01

    Single molecule based superresolution techniques (STORM/PALM) achieve nanometer spatial resolution by integrating the temporal information of the switching dynamics of fluorophores (emitters). When emitter density is low for each frame, they are located to the nanometer resolution. However, when the emitter density rises, causing significant overlapping, it becomes increasingly difficult to accurately locate individual emitters. This is particularly apparent in three dimensional (3D) localization because of the large effective volume of the 3D point spread function (PSF). The inability to precisely locate the emitters at a high density causes poor temporal resolution of localization-based superresolution technique and significantly limits its application in 3D live cell imaging. To address this problem, we developed a 3D high-density superresolution imaging platform that allows us to precisely locate the positions of emitters, even when they are significantly overlapped in three dimensional space. Our platform involves a multi-focus system in combination with astigmatic optics and an ℓ1-Homotopy optimization procedure. To reduce the intrinsic bias introduced by the discrete formulation of compressed sensing, we introduced a debiasing step followed by a 3D weighted centroid procedure, which not only increases the localization accuracy, but also increases the computation speed of image reconstruction. We implemented our algorithms on a graphic processing unit (GPU), which speeds up processing 10 times compared with central processing unit (CPU) implementation. We tested our method with both simulated data and experimental data of fluorescently labeled microtubules and were able to reconstruct a 3D microtubule image with 1000 frames (512×512) acquired within 20 seconds. PMID:25798314

  4. Anatomy-based 3D skeleton extraction from femur model.

    PubMed

    Gharenazifam, Mina; Arbabi, Ehsan

    2014-11-01

    Using 3D models of bones can highly improve accuracy and reliability of orthopaedic evaluation. However, it may impose excessive computational load. This article proposes a fully automatic method for extracting a compact model of the femur from its 3D model. The proposed method works by extracting a 3D skeleton based on the clinical parameters of the femur. Therefore, in addition to summarizing a 3D model of the bone, the extracted skeleton would preserve important clinical and anatomical information. The proposed method has been applied on 3D models of 10 femurs and the results have been evaluated for different resolutions of data.

  5. Multisensor fusion for 3-D defect characterization using wavelet basis function neural networks

    NASA Astrophysics Data System (ADS)

    Lim, Jaein; Udpa, Satish S.; Udpa, Lalita; Afzal, Muhammad

    2001-04-01

    The primary objective of multi-sensor data fusion, which offers both quantitative and qualitative benefits, has the ability to draw inferences that may not be feasible with data from a single sensor alone. In this paper, data from two sets of sensors are fused to estimate the defect profile from magnetic flux leakage (MFL) inspection data. The two sensors measure the axial and circumferential components of the MFL. Data is fused at the signal level. If the flux is oriented axially, the samples of the axial signal are measured along a direction parallel to the flaw, while the circumferential signal is measured in a direction that is perpendicular to the flaw. The two signals are combined as the real and imaginary components of a complex valued signal. Signals from an array of sensors are arranged in contiguous rows to obtain a complex valued image. A boundary extraction algorithm is used to extract the defect areas in the image. Signals from the defect regions are then processed to minimize noise and the effects of lift-off. Finally, a wavelet basis function (WBF) neural network is employed to map the complex valued image appropriately to obtain the geometrical profile of the defect. The feasibility of the approach was evaluated using the data obtained from the MFL inspection of natural gas transmission pipelines. Results show the effectiveness of the approach.

  6. Review: Polymeric-Based 3D Printing for Tissue Engineering.

    PubMed

    Wu, Geng-Hsi; Hsu, Shan-Hui

    Three-dimensional (3D) printing, also referred to as additive manufacturing, is a technology that allows for customized fabrication through computer-aided design. 3D printing has many advantages in the fabrication of tissue engineering scaffolds, including fast fabrication, high precision, and customized production. Suitable scaffolds can be designed and custom-made based on medical images such as those obtained from computed tomography. Many 3D printing methods have been employed for tissue engineering. There are advantages and limitations for each method. Future areas of interest and progress are the development of new 3D printing platforms, scaffold design software, and materials for tissue engineering applications.

  7. Image based 3D city modeling : Comparative study

    NASA Astrophysics Data System (ADS)

    Singh, S. P.; Jain, K.; Mandla, V. R.

    2014-06-01

    3D city model is a digital representation of the Earth's surface and it's related objects such as building, tree, vegetation, and some manmade feature belonging to urban area. The demand of 3D city modeling is increasing rapidly for various engineering and non-engineering applications. Generally four main image based approaches were used for virtual 3D city models generation. In first approach, researchers were used Sketch based modeling, second method is Procedural grammar based modeling, third approach is Close range photogrammetry based modeling and fourth approach is mainly based on Computer Vision techniques. SketchUp, CityEngine, Photomodeler and Agisoft Photoscan are the main softwares to represent these approaches respectively. These softwares have different approaches & methods suitable for image based 3D city modeling. Literature study shows that till date, there is no complete such type of comparative study available to create complete 3D city model by using images. This paper gives a comparative assessment of these four image based 3D modeling approaches. This comparative study is mainly based on data acquisition methods, data processing techniques and output 3D model products. For this research work, study area is the campus of civil engineering department, Indian Institute of Technology, Roorkee (India). This 3D campus acts as a prototype for city. This study also explains various governing parameters, factors and work experiences. This research work also gives a brief introduction, strengths and weakness of these four image based techniques. Some personal comment is also given as what can do or what can't do from these softwares. At the last, this study shows; it concluded that, each and every software has some advantages and limitations. Choice of software depends on user requirements of 3D project. For normal visualization project, SketchUp software is a good option. For 3D documentation record, Photomodeler gives good result. For Large city

  8. NoSQL Based 3D City Model Management System

    NASA Astrophysics Data System (ADS)

    Mao, B.; Harrie, L.; Cao, J.; Wu, Z.; Shen, J.

    2014-04-01

    To manage increasingly complicated 3D city models, a framework based on NoSQL database is proposed in this paper. The framework supports import and export of 3D city model according to international standards such as CityGML, KML/COLLADA and X3D. We also suggest and implement 3D model analysis and visualization in the framework. For city model analysis, 3D geometry data and semantic information (such as name, height, area, price and so on) are stored and processed separately. We use a Map-Reduce method to deal with the 3D geometry data since it is more complex, while the semantic analysis is mainly based on database query operation. For visualization, a multiple 3D city representation structure CityTree is implemented within the framework to support dynamic LODs based on user viewpoint. Also, the proposed framework is easily extensible and supports geoindexes to speed up the querying. Our experimental results show that the proposed 3D city management system can efficiently fulfil the analysis and visualization requirements.

  9. Surgeon-Based 3D Printing for Microvascular Bone Flaps.

    PubMed

    Taylor, Erin M; Iorio, Matthew L

    2017-03-04

    Background Three-dimensional (3D) printing has developed as a revolutionary technology with the capacity to design accurate physical models in preoperative planning. We present our experience in surgeon-based design of 3D models, using home 3D software and printing technology for use as an adjunct in vascularized bone transfer. Methods Home 3D printing techniques were used in the design and execution of vascularized bone flap transfers to the upper extremity. Open source imaging software was used to convert preoperative computed tomography scans and create 3D models. These were printed in the surgeon's office as 3D models for the planned reconstruction. Vascularized bone flaps were designed intraoperatively based on the 3D printed models. Results Three-dimensional models were created for intraoperative use in vascularized bone flaps, including (1) medial femoral trochlea (MFT) flap for scaphoid avascular necrosis and nonunion, (2) MFT flap for lunate avascular necrosis and nonunion, (3) medial femoral condyle (MFC) flap for wrist arthrodesis, and (4) free fibula osteocutaneous flap for distal radius septic nonunion. Templates based on the 3D models allowed for the precise and rapid contouring of well-vascularized bone flaps in situ, prior to ligating the donor pedicle. Conclusions Surgeon-based 3D printing is a feasible, innovative technology that allows for the precise and rapid contouring of models that can be created in various configurations for pre- and intraoperative planning. The technology is easy to use, convenient, and highly economical as compared with traditional send-out manufacturing. Surgeon-based 3D printing is a useful adjunct in vascularized bone transfer. Level of Evidence Level IV.

  10. 3D Printing of Carbon Nanotubes-Based Microsupercapacitors.

    PubMed

    Yu, Wei; Zhou, Han; Li, Ben Q; Ding, Shujiang

    2017-02-08

    A novel 3D printing procedure is presented for fabricating carbon-nanotubes (CNTs)-based microsupercapacitors. The 3D printer uses a CNTs ink slurry with a moderate solid content and prints a stream of continuous droplets. Appropriate control of a heated base is applied to facilitate the solvent removal and adhesion between printed layers and to improve the structure integrity without structure delamination or distortion upon drying. The 3D-printed electrodes for microsupercapacitors are characterized by SEM, laser scanning confocal microscope, and step profiler. Effect of process parameters on 3D printing is also studied. The final solid-state microsupercapacitors are assembled with the printed multilayer CNTs structures and poly(vinyl alcohol)-H3PO4 gel as the interdigitated microelectrodes and electrolyte. The electrochemical performance of 3D printed microsupercapacitors is also tested, showing a significant areal capacitance and excellent cycle stability.

  11. Reconstruction-based 3D/2D image registration.

    PubMed

    Tomazevic, Dejan; Likar, Bostjan; Pernus, Franjo

    2005-01-01

    In this paper we present a novel 3D/2D registration method, where first, a 3D image is reconstructed from a few 2D X-ray images and next, the preoperative 3D image is brought into the best possible spatial correspondence with the reconstructed image by optimizing a similarity measure. Because the quality of the reconstructed image is generally low, we introduce a novel asymmetric mutual information similarity measure, which is able to cope with low image quality as well as with different imaging modalities. The novel 3D/2D registration method has been evaluated using standardized evaluation methodology and publicly available 3D CT, 3DRX, and MR and 2D X-ray images of two spine phantoms, for which gold standard registrations were known. In terms of robustness, reliability and capture range the proposed method outperformed the gradient-based method and the method based on digitally reconstructed radiographs (DRRs).

  12. Optical Aperture Synthesis Object's Information Extracting Based on Wavelet Denoising

    NASA Astrophysics Data System (ADS)

    Fan, W. J.; Lu, Y.

    2006-10-01

    Wavelet denoising is studied to improve OAS(optical aperture synthesis) object's Fourier information extracting. Translation invariance wavelet denoising based on Donoho wavelet soft threshold denoising is researched to remove Pseudo-Gibbs in wavelet soft threshold image. OAS object's information extracting based on translation invariance wavelet denoising is studied. The study shows that wavelet threshold denoising can improve the precision and the repetition of object's information extracting from interferogram, and the translation invariance wavelet denoising information extracting is better than soft threshold wavelet denoising information extracting.

  13. Wavelet-Based Adaptive Denoising of Phonocardiographic Records

    DTIC Science & Technology

    2007-11-02

    the approximated signal, and d the signal details at the given scale; h and g are biorthogonal filters, corresponding to the selected mother wavelet ...dyadic scale can be written as: where is the orthogonal mother wavelet , and: The discrete version of the dyadic wavelet transform can be based on... wavelet with 4 moments equal to zero (Coiflet-2) as the mother wavelet . The two channels were wavelet decomposed up to the 9th order (i = 0, 1 ... 8

  14. 3D face recognition by projection-based methods

    NASA Astrophysics Data System (ADS)

    Dutagaci, Helin; Sankur, Bülent; Yemez, Yücel

    2006-02-01

    In this paper, we investigate recognition performances of various projection-based features applied on registered 3D scans of faces. Some features are data driven, such as ICA-based features or NNMF-based features. Other features are obtained using DFT or DCT-based schemes. We apply the feature extraction techniques to three different representations of registered faces, namely, 3D point clouds, 2D depth images and 3D voxel. We consider both global and local features. Global features are extracted from the whole face data, whereas local features are computed over the blocks partitioned from 2D depth images. The block-based local features are fused both at feature level and at decision level. The resulting feature vectors are matched using Linear Discriminant Analysis. Experiments using different combinations of representation types and feature vectors are conducted on the 3D-RMA dataset.

  15. 3D Printed Graphene Based Energy Storage Devices.

    PubMed

    Foster, Christopher W; Down, Michael P; Zhang, Yan; Ji, Xiaobo; Rowley-Neale, Samuel J; Smith, Graham C; Kelly, Peter J; Banks, Craig E

    2017-03-03

    3D printing technology provides a unique platform for rapid prototyping of numerous applications due to its ability to produce low cost 3D printed platforms. Herein, a graphene-based polylactic acid filament (graphene/PLA) has been 3D printed to fabricate a range of 3D disc electrode (3DE) configurations using a conventional RepRap fused deposition moulding (FDM) 3D printer, which requires no further modification/ex-situ curing step. To provide proof-of-concept, these 3D printed electrode architectures are characterised both electrochemically and physicochemically and are advantageously applied as freestanding anodes within Li-ion batteries and as solid-state supercapacitors. These freestanding anodes neglect the requirement for a current collector, thus offering a simplistic and cheaper alternative to traditional Li-ion based setups. Additionally, the ability of these devices' to electrochemically produce hydrogen via the hydrogen evolution reaction (HER) as an alternative to currently utilised platinum based electrodes (with in electrolysers) is also performed. The 3DE demonstrates an unexpectedly high catalytic activity towards the HER (-0.46 V vs. SCE) upon the 1000th cycle, such potential is the closest observed to the desired value of platinum at (-0.25 V vs. SCE). We subsequently suggest that 3D printing of graphene-based conductive filaments allows for the simple fabrication of energy storage devices with bespoke and conceptual designs to be realised.

  16. 3D Printed Graphene Based Energy Storage Devices

    PubMed Central

    Foster, Christopher W.; Down, Michael P.; Zhang, Yan; Ji, Xiaobo; Rowley-Neale, Samuel J.; Smith, Graham C.; Kelly, Peter J.; Banks, Craig E.

    2017-01-01

    3D printing technology provides a unique platform for rapid prototyping of numerous applications due to its ability to produce low cost 3D printed platforms. Herein, a graphene-based polylactic acid filament (graphene/PLA) has been 3D printed to fabricate a range of 3D disc electrode (3DE) configurations using a conventional RepRap fused deposition moulding (FDM) 3D printer, which requires no further modification/ex-situ curing step. To provide proof-of-concept, these 3D printed electrode architectures are characterised both electrochemically and physicochemically and are advantageously applied as freestanding anodes within Li-ion batteries and as solid-state supercapacitors. These freestanding anodes neglect the requirement for a current collector, thus offering a simplistic and cheaper alternative to traditional Li-ion based setups. Additionally, the ability of these devices’ to electrochemically produce hydrogen via the hydrogen evolution reaction (HER) as an alternative to currently utilised platinum based electrodes (with in electrolysers) is also performed. The 3DE demonstrates an unexpectedly high catalytic activity towards the HER (−0.46 V vs. SCE) upon the 1000th cycle, such potential is the closest observed to the desired value of platinum at (−0.25 V vs. SCE). We subsequently suggest that 3D printing of graphene-based conductive filaments allows for the simple fabrication of energy storage devices with bespoke and conceptual designs to be realised. PMID:28256602

  17. 3D Printed Graphene Based Energy Storage Devices

    NASA Astrophysics Data System (ADS)

    Foster, Christopher W.; Down, Michael P.; Zhang, Yan; Ji, Xiaobo; Rowley-Neale, Samuel J.; Smith, Graham C.; Kelly, Peter J.; Banks, Craig E.

    2017-03-01

    3D printing technology provides a unique platform for rapid prototyping of numerous applications due to its ability to produce low cost 3D printed platforms. Herein, a graphene-based polylactic acid filament (graphene/PLA) has been 3D printed to fabricate a range of 3D disc electrode (3DE) configurations using a conventional RepRap fused deposition moulding (FDM) 3D printer, which requires no further modification/ex-situ curing step. To provide proof-of-concept, these 3D printed electrode architectures are characterised both electrochemically and physicochemically and are advantageously applied as freestanding anodes within Li-ion batteries and as solid-state supercapacitors. These freestanding anodes neglect the requirement for a current collector, thus offering a simplistic and cheaper alternative to traditional Li-ion based setups. Additionally, the ability of these devices’ to electrochemically produce hydrogen via the hydrogen evolution reaction (HER) as an alternative to currently utilised platinum based electrodes (with in electrolysers) is also performed. The 3DE demonstrates an unexpectedly high catalytic activity towards the HER (‑0.46 V vs. SCE) upon the 1000th cycle, such potential is the closest observed to the desired value of platinum at (‑0.25 V vs. SCE). We subsequently suggest that 3D printing of graphene-based conductive filaments allows for the simple fabrication of energy storage devices with bespoke and conceptual designs to be realised.

  18. 3D object recognition based on local descriptors

    NASA Astrophysics Data System (ADS)

    Jakab, Marek; Benesova, Wanda; Racev, Marek

    2015-01-01

    In this paper, we propose an enhanced method of 3D object description and recognition based on local descriptors using RGB image and depth information (D) acquired by Kinect sensor. Our main contribution is focused on an extension of the SIFT feature vector by the 3D information derived from the depth map (SIFT-D). We also propose a novel local depth descriptor (DD) that includes a 3D description of the key point neighborhood. Thus defined the 3D descriptor can then enter the decision-making process. Two different approaches have been proposed, tested and evaluated in this paper. First approach deals with the object recognition system using the original SIFT descriptor in combination with our novel proposed 3D descriptor, where the proposed 3D descriptor is responsible for the pre-selection of the objects. Second approach demonstrates the object recognition using an extension of the SIFT feature vector by the local depth description. In this paper, we present the results of two experiments for the evaluation of the proposed depth descriptors. The results show an improvement in accuracy of the recognition system that includes the 3D local description compared with the same system without the 3D local description. Our experimental system of object recognition is working near real-time.

  19. Lossy to lossless object-based coding of 3-D MRI data.

    PubMed

    Menegaz, Gloria; Thiran, Jean-Philippe

    2002-01-01

    We propose a fully three-dimensional (3-D) object-based coding system exploiting the diagnostic relevance of the different regions of the volumetric data for rate allocation. The data are first decorrelated via a 3-D discrete wavelet transform. The implementation via the lifting steps scheme allows to map integer-to-integer values, enabling lossless coding, and facilitates the definition of the object-based inverse transform. The coding process assigns disjoint segments of the bitstream to the different objects, which can be independently accessed and reconstructed at any up-to-lossless quality. Two fully 3-D coding strategies are considered: embedded zerotree coding (EZW-3D) and multidimensional layered zero coding (MLZC), both generalized for region of interest (ROI)-based processing. In order to avoid artifacts along region boundaries, some extra coefficients must be encoded for each object. This gives rise to an overheading of the bitstream with respect to the case where the volume is encoded as a whole. The amount of such extra information depends on both the filter length and the decomposition depth. The system is characterized on a set of head magnetic resonance images. Results show that MLZC and EZW-3D have competitive performances. In particular, the best MLZC mode outperforms the others state-of-the-art techniques on one of the datasets for which results are available in the literature.

  20. Powder-based 3D printing for bone tissue engineering.

    PubMed

    Brunello, G; Sivolella, S; Meneghello, R; Ferroni, L; Gardin, C; Piattelli, A; Zavan, B; Bressan, E

    2016-01-01

    Bone tissue engineered 3-D constructs customized to patient-specific needs are emerging as attractive biomimetic scaffolds to enhance bone cell and tissue growth and differentiation. The article outlines the features of the most common additive manufacturing technologies (3D printing, stereolithography, fused deposition modeling, and selective laser sintering) used to fabricate bone tissue engineering scaffolds. It concentrates, in particular, on the current state of knowledge concerning powder-based 3D printing, including a description of the properties of powders and binder solutions, the critical phases of scaffold manufacturing, and its applications in bone tissue engineering. Clinical aspects and future applications are also discussed.

  1. Visual Semantic Based 3D Video Retrieval System Using HDFS

    PubMed Central

    Kumar, C.Ranjith; Suguna, S.

    2016-01-01

    This paper brings out a neoteric frame of reference for visual semantic based 3d video search and retrieval applications. Newfangled 3D retrieval application spotlight on shape analysis like object matching, classification and retrieval not only sticking up entirely with video retrieval. In this ambit, we delve into 3D-CBVR (Content Based Video Retrieval) concept for the first time. For this purpose, we intent to hitch on BOVW and Mapreduce in 3D framework. Instead of conventional shape based local descriptors, we tried to coalesce shape, color and texture for feature extraction. For this purpose, we have used combination of geometric & topological features for shape and 3D co-occurrence matrix for color and texture. After thriving extraction of local descriptors, TB-PCT (Threshold Based- Predictive Clustering Tree) algorithm is used to generate visual codebook and histogram is produced. Further, matching is performed using soft weighting scheme with L2 distance function. As a final step, retrieved results are ranked according to the Index value and acknowledged to the user as a feedback .In order to handle prodigious amount of data and Efficacious retrieval, we have incorporated HDFS in our Intellection. Using 3D video dataset, we future the performance of our proposed system which can pan out that the proposed work gives meticulous result and also reduce the time intricacy. PMID:28003793

  2. Visual Semantic Based 3D Video Retrieval System Using HDFS.

    PubMed

    Kumar, C Ranjith; Suguna, S

    2016-08-01

    This paper brings out a neoteric frame of reference for visual semantic based 3d video search and retrieval applications. Newfangled 3D retrieval application spotlight on shape analysis like object matching, classification and retrieval not only sticking up entirely with video retrieval. In this ambit, we delve into 3D-CBVR (Content Based Video Retrieval) concept for the first time. For this purpose, we intent to hitch on BOVW and Mapreduce in 3D framework. Instead of conventional shape based local descriptors, we tried to coalesce shape, color and texture for feature extraction. For this purpose, we have used combination of geometric & topological features for shape and 3D co-occurrence matrix for color and texture. After thriving extraction of local descriptors, TB-PCT (Threshold Based- Predictive Clustering Tree) algorithm is used to generate visual codebook and histogram is produced. Further, matching is performed using soft weighting scheme with L2 distance function. As a final step, retrieved results are ranked according to the Index value and acknowledged to the user as a feedback .In order to handle prodigious amount of data and Efficacious retrieval, we have incorporated HDFS in our Intellection. Using 3D video dataset, we future the performance of our proposed system which can pan out that the proposed work gives meticulous result and also reduce the time intricacy.

  3. All-optical image processing and compression based on Haar wavelet transform.

    PubMed

    Parca, Giorgia; Teixeira, Pedro; Teixeira, Antonio

    2013-04-20

    Fast data processing and compression methods based on wavelet transform are fundamental tools in the area of real-time 2D data/image analysis, enabling high definition applications and redundant data reduction. The need for information processing at high data rates motivates the efforts on exploiting the speed and the parallelism of the light for data analysis and compression. Among several schemes for optical wavelet transform implementation, the Haar transform offers simple design and fast computation, plus it can be easily implemented by optical planar interferometry. We present an all optical scheme based on an asymmetric couplers network for achieving fast image processing and compression in the optical domain. The implementation of Haar wavelet transform through a 3D passive structure is supported by theoretical formulation and simulations results. Asymmetrical coupler 3D network design and optimization are reported and Haar wavelet transform, including compression, was achieved, thus demonstrating the feasibility of our approach.

  4. Contour detection based on wavelet differentiation

    NASA Astrophysics Data System (ADS)

    Bezuglov, D.; Kuzin, A.; Voronin, V.

    2016-05-01

    This work proposes a novel algorithm for contour detection based on high-performance algorithm of wavelet analysis for multimedia applications. To solve the noise effect on the result of peaking in this paper we consider the direct and inverse wavelet differentiation. Extensive experimental evaluation on noisy images demonstrates that our contour detection method significantly outperform competing algorithms. The proposed algorithm provides a means of coupling our system to recognition application such as detection and identification of vehicle number plate.

  5. 3D model retrieval method based on mesh segmentation

    NASA Astrophysics Data System (ADS)

    Gan, Yuanchao; Tang, Yan; Zhang, Qingchen

    2012-04-01

    In the process of feature description and extraction, current 3D model retrieval algorithms focus on the global features of 3D models but ignore the combination of global and local features of the model. For this reason, they show less effective performance to the models with similar global shape and different local shape. This paper proposes a novel algorithm for 3D model retrieval based on mesh segmentation. The key idea is to exact the structure feature and the local shape feature of 3D models, and then to compares the similarities of the two characteristics and the total similarity between the models. A system that realizes this approach was built and tested on a database of 200 objects and achieves expected results. The results show that the proposed algorithm improves the precision and the recall rate effectively.

  6. Wavelet-based acoustic recognition of aircraft

    SciTech Connect

    Dress, W.B.; Kercel, S.W.

    1994-09-01

    We describe a wavelet-based technique for identifying aircraft from acoustic emissions during take-off and landing. Tests show that the sensor can be a single, inexpensive hearing-aid microphone placed close to the ground the paper describes data collection, analysis by various technique, methods of event classification, and extraction of certain physical parameters from wavelet subspace projections. The primary goal of this paper is to show that wavelet analysis can be used as a divide-and-conquer first step in signal processing, providing both simplification and noise filtering. The idea is to project the original signal onto the orthogonal wavelet subspaces, both details and approximations. Subsequent analysis, such as system identification, nonlinear systems analysis, and feature extraction, is then carried out on the various signal subspaces.

  7. 3D microstructure modeling of compressed fiber-based materials

    NASA Astrophysics Data System (ADS)

    Gaiselmann, Gerd; Tötzke, Christian; Manke, Ingo; Lehnert, Werner; Schmidt, Volker

    2014-07-01

    A novel parametrized model that describes the 3D microstructure of compressed fiber-based materials is introduced. It allows to virtually generate the microstructure of realistically compressed gas-diffusion layers (GDL). Given the input of a 3D microstructure of some fiber-based material, the model compresses the system of fibers in a uniaxial direction for arbitrary compression rates. The basic idea is to translate the fibers in the direction of compression according to a vector field which depends on the rate of compression and on the locations of fibers within the material. In order to apply the model to experimental 3D image data of fiber-based materials given for several compression states, an optimal vector field is estimated by simulated annealing. The model is applied to 3D image data of non-woven GDL in PEMFC gained by synchrotron tomography for different compression rates. The compression model is validated by comparing structural characteristics computed for experimentally compressed and virtually compressed microstructures, where two kinds of compression - using a flat stamp and a stamp with a flow-field profile - are applied. For both stamps types, a good agreement is found. Furthermore, the compression model is combined with a stochastic 3D microstructure model for uncompressed fiber-based materials. This allows to efficiently generate compressed fiber-based microstructures in arbitrary volumes.

  8. 3D ear identification based on sparse representation.

    PubMed

    Zhang, Lin; Ding, Zhixuan; Li, Hongyu; Shen, Ying

    2014-01-01

    Biometrics based personal authentication is an effective way for automatically recognizing, with a high confidence, a person's identity. Recently, 3D ear shape has attracted tremendous interests in research field due to its richness of feature and ease of acquisition. However, the existing ICP (Iterative Closet Point)-based 3D ear matching methods prevalent in the literature are not quite efficient to cope with the one-to-many identification case. In this paper, we aim to fill this gap by proposing a novel effective fully automatic 3D ear identification system. We at first propose an accurate and efficient template-based ear detection method. By utilizing such a method, the extracted ear regions are represented in a common canonical coordinate system determined by the ear contour template, which facilitates much the following stages of feature extraction and classification. For each extracted 3D ear, a feature vector is generated as its representation by making use of a PCA-based local feature descriptor. At the stage of classification, we resort to the sparse representation based classification approach, which actually solves an l1-minimization problem. To the best of our knowledge, this is the first work introducing the sparse representation framework into the field of 3D ear identification. Extensive experiments conducted on a benchmark dataset corroborate the effectiveness and efficiency of the proposed approach. The associated Matlab source code and the evaluation results have been made publicly online available at http://sse.tongji.edu.cn/linzhang/ear/srcear/srcear.htm.

  9. DCT and DST Based Image Compression for 3D Reconstruction

    NASA Astrophysics Data System (ADS)

    Siddeq, Mohammed M.; Rodrigues, Marcos A.

    2017-03-01

    This paper introduces a new method for 2D image compression whose quality is demonstrated through accurate 3D reconstruction using structured light techniques and 3D reconstruction from multiple viewpoints. The method is based on two discrete transforms: (1) A one-dimensional Discrete Cosine Transform (DCT) is applied to each row of the image. (2) The output from the previous step is transformed again by a one-dimensional Discrete Sine Transform (DST), which is applied to each column of data generating new sets of high-frequency components followed by quantization of the higher frequencies. The output is then divided into two parts where the low-frequency components are compressed by arithmetic coding and the high frequency ones by an efficient minimization encoding algorithm. At decompression stage, a binary search algorithm is used to recover the original high frequency components. The technique is demonstrated by compressing 2D images up to 99% compression ratio. The decompressed images, which include images with structured light patterns for 3D reconstruction and from multiple viewpoints, are of high perceptual quality yielding accurate 3D reconstruction. Perceptual assessment and objective quality of compression are compared with JPEG and JPEG2000 through 2D and 3D RMSE. Results show that the proposed compression method is superior to both JPEG and JPEG2000 concerning 3D reconstruction, and with equivalent perceptual quality to JPEG2000.

  10. 3D display based on parallax barrier with multiview zones.

    PubMed

    Lv, Guo-Jiao; Wang, Qiong-Hua; Zhao, Wu-Xiang; Wang, Jun

    2014-03-01

    A 3D display based on a parallax barrier with multiview zones is proposed. This display consists of a 2D display panel and a parallax barrier. The basic element of the parallax barrier has three narrow slits. They can show three columns of subpixels on the 2D display panel and form 3D pixels. The parallax barrier can provide multiview zones. In these multiview zones, the proposed 3D display can use a small number of views to achieve a high density of views. Therefore, the distance between views is the same as the conventional ones with more views. Considering the proposed display has fewer views, which bring more 3D pixels in the 3D images, the resolution and brightness will be higher than the conventional ones. A 12-view prototype of the proposed 3D display is developed, and it provides the same density of views as a conventional one with 28 views. Experimental results show the proposed display has higher resolution and brightness than the conventional one. The cross talk is also limited at a low level.

  11. 3D measurement system based on computer-generated gratings

    NASA Astrophysics Data System (ADS)

    Zhu, Yongjian; Pan, Weiqing; Luo, Yanliang

    2010-08-01

    A new kind of 3D measurement system has been developed to achieve the 3D profile of complex object. The principle of measurement system is based on the triangular measurement of digital fringe projection, and the fringes are fully generated from computer. Thus the computer-generated four fringes form the data source of phase-shifting 3D profilometry. The hardware of system includes the computer, video camera, projector, image grabber, and VGA board with two ports (one port links to the screen, another to the projector). The software of system consists of grating projection module, image grabbing module, phase reconstructing module and 3D display module. A software-based synchronizing method between grating projection and image capture is proposed. As for the nonlinear error of captured fringes, a compensating method is introduced based on the pixel-to-pixel gray correction. At the same time, a least square phase unwrapping is used to solve the problem of phase reconstruction by using the combination of Log Modulation Amplitude and Phase Derivative Variance (LMAPDV) as weight. The system adopts an algorithm from Matlab Tool Box for camera calibration. The 3D measurement system has an accuracy of 0.05mm. The execution time of system is 3~5s for one-time measurement.

  12. Voice and gesture-based 3D multimedia presentation tool

    NASA Astrophysics Data System (ADS)

    Fukutake, Hiromichi; Akazawa, Yoshiaki; Okada, Yoshihiro

    2007-09-01

    This paper proposes a 3D multimedia presentation tool that allows the user to manipulate intuitively only through the voice input and the gesture input without using a standard keyboard or a mouse device. The authors developed this system as a presentation tool to be used in a presentation room equipped a large screen like an exhibition room in a museum because, in such a presentation environment, it is better to use voice commands and the gesture pointing input rather than using a keyboard or a mouse device. This system was developed using IntelligentBox, which is a component-based 3D graphics software development system. IntelligentBox has already provided various types of 3D visible, reactive functional components called boxes, e.g., a voice input component and various multimedia handling components. IntelligentBox also provides a dynamic data linkage mechanism called slot-connection that allows the user to develop 3D graphics applications by combining already existing boxes through direct manipulations on a computer screen. Using IntelligentBox, the 3D multimedia presentation tool proposed in this paper was also developed as combined components only through direct manipulations on a computer screen. The authors have already proposed a 3D multimedia presentation tool using a stage metaphor and its voice input interface. This time, we extended the system to make it accept the user gesture input besides voice commands. This paper explains details of the proposed 3D multimedia presentation tool and especially describes its component-based voice and gesture input interfaces.

  13. Hough transform-based 3D mesh retrieval

    NASA Astrophysics Data System (ADS)

    Zaharia, Titus; Preteux, Francoise J.

    2001-11-01

    This papre addresses the issue of 3D mesh indexation by using shape descriptors (SDs) under constraints of geometric and topological invariance. A new shape descriptor, the Optimized 3D Hough Transform Descriptor (O3HTD) is here proposed. Intrinsically topologically stable, the O3DHTD is not invariant to geometric transformations. Nevertheless, we show mathematically how the O3DHTD can be optimally associated (in terms of compactness of representation and computational complexity) with a spatial alignment procedure which leads to a geometric invariant behavior. Experimental results have been carried out upon the MPEG-7 3D model database consisting of about 1300 meshes in VRML 2.0 format. Objective retrieval results, based upon the definition of a categorized ground truth subset, are reported in terms of Bull Eye Percentage (BEP) score and compared to those obtained by applying the MPEg-7 3D SD. It is shown that the O3DHTD outperforms the MPEg-7 3D SD of up to 28%.

  14. Optical 3D watermark based digital image watermarking for telemedicine

    NASA Astrophysics Data System (ADS)

    Li, Xiao Wei; Kim, Seok Tae

    2013-12-01

    Region of interest (ROI) of a medical image is an area including important diagnostic information and must be stored without any distortion. This algorithm for application of watermarking technique for non-ROI of the medical image preserving ROI. The paper presents a 3D watermark based medical image watermarking scheme. In this paper, a 3D watermark object is first decomposed into 2D elemental image array (EIA) by a lenslet array, and then the 2D elemental image array data is embedded into the host image. The watermark extraction process is an inverse process of embedding. The extracted EIA through the computational integral imaging reconstruction (CIIR) technique, the 3D watermark can be reconstructed. Because the EIA is composed of a number of elemental images possesses their own perspectives of a 3D watermark object. Even though the embedded watermark data badly damaged, the 3D virtual watermark can be successfully reconstructed. Furthermore, using CAT with various rule number parameters, it is possible to get many channels for embedding. So our method can recover the weak point having only one transform plane in traditional watermarking methods. The effectiveness of the proposed watermarking scheme is demonstrated with the aid of experimental results.

  15. Applications of Alginate-Based Bioinks in 3D Bioprinting

    PubMed Central

    Axpe, Eneko; Oyen, Michelle L.

    2016-01-01

    Three-dimensional (3D) bioprinting is on the cusp of permitting the direct fabrication of artificial living tissue. Multicellular building blocks (bioinks) are dispensed layer by layer and scaled for the target construct. However, only a few materials are able to fulfill the considerable requirements for suitable bioink formulation, a critical component of efficient 3D bioprinting. Alginate, a naturally occurring polysaccharide, is clearly the most commonly employed material in current bioinks. Here, we discuss the benefits and disadvantages of the use of alginate in 3D bioprinting by summarizing the most recent studies that used alginate for printing vascular tissue, bone and cartilage. In addition, other breakthroughs in the use of alginate in bioprinting are discussed, including strategies to improve its structural and degradation characteristics. In this review, we organize the available literature in order to inspire and accelerate novel alginate-based bioink formulations with enhanced properties for future applications in basic research, drug screening and regenerative medicine. PMID:27898010

  16. Perception-based shape retrieval for 3D building models

    NASA Astrophysics Data System (ADS)

    Zhang, Man; Zhang, Liqiang; Takis Mathiopoulos, P.; Ding, Yusi; Wang, Hao

    2013-01-01

    With the help of 3D search engines, a large number of 3D building models can be retrieved freely online. A serious disadvantage of most rotation-insensitive shape descriptors is their inability to distinguish between two 3D building models which are different at their main axes, but appear similar when one of them is rotated. To resolve this problem, we present a novel upright-based normalization method which not only correctly rotates such building models, but also greatly simplifies and accelerates the abstraction and the matching of building models' shape descriptors. Moreover, the abundance of architectural styles significantly hinders the effective shape retrieval of building models. Our research has shown that buildings with different designs are not well distinguished by the widely recognized shape descriptors for general 3D models. Motivated by this observation and to further improve the shape retrieval quality, a new building matching method is introduced and analyzed based on concepts found in the field of perception theory and the well-known Light Field descriptor. The resulting normalized building models are first classified using the qualitative shape descriptors of Shell and Unevenness which outline integral geometrical and topological information. These models are then put in on orderly fashion with the help of an improved quantitative shape descriptor which we will term as Horizontal Light Field Descriptor, since it assembles detailed shape characteristics. To accurately evaluate the proposed methodology, an enlarged building shape database which extends previous well-known shape benchmarks was implemented as well as a model retrieval system supporting inputs from 2D sketches and 3D models. Various experimental performance evaluation results have shown that, as compared to previous methods, retrievals employing the proposed matching methodology are faster and more consistent with human recognition of spatial objects. In addition these performance

  17. 3D Ear Identification Based on Sparse Representation

    PubMed Central

    Zhang, Lin; Ding, Zhixuan; Li, Hongyu; Shen, Ying

    2014-01-01

    Biometrics based personal authentication is an effective way for automatically recognizing, with a high confidence, a person’s identity. Recently, 3D ear shape has attracted tremendous interests in research field due to its richness of feature and ease of acquisition. However, the existing ICP (Iterative Closet Point)-based 3D ear matching methods prevalent in the literature are not quite efficient to cope with the one-to-many identification case. In this paper, we aim to fill this gap by proposing a novel effective fully automatic 3D ear identification system. We at first propose an accurate and efficient template-based ear detection method. By utilizing such a method, the extracted ear regions are represented in a common canonical coordinate system determined by the ear contour template, which facilitates much the following stages of feature extraction and classification. For each extracted 3D ear, a feature vector is generated as its representation by making use of a PCA-based local feature descriptor. At the stage of classification, we resort to the sparse representation based classification approach, which actually solves an l1-minimization problem. To the best of our knowledge, this is the first work introducing the sparse representation framework into the field of 3D ear identification. Extensive experiments conducted on a benchmark dataset corroborate the effectiveness and efficiency of the proposed approach. The associated Matlab source code and the evaluation results have been made publicly online available at http://sse.tongji.edu.cn/linzhang/ear/srcear/srcear.htm. PMID:24740247

  18. Wavelet-based coding of ultraspectral sounder data

    NASA Astrophysics Data System (ADS)

    Garcia-Vilchez, Fernando; Serra-Sagrista, Joan; Auli-Llinas, Francesc

    2005-08-01

    In this paper we provide a study concerning the suitability of well-known image coding techniques originally devised for lossy compression of still natural images when applied to lossless compression of ultraspectral sounder data. We present here the experimental results of six wavelet-based widespread coding techniques, namely EZW, IC, SPIHT, JPEG2000, SPECK and CCSDS-IDC. Since the considered techniques are 2-dimensional (2D) in nature but the ultraspectral data are 3D, a pre-processing stage is applied to convert the two spatial dimensions into a single spatial dimension. All the wavelet-based techniques are competitive when compared either to the benchmark prediction-based methods for lossless compression, CALIC and JPEG-LS, or to two common compression utilities, GZIP and BZIP2. EZW, SPIHT, SPECK and CCSDS-IDC provide a very similar performance, while IC and JPEG2000 improve the compression factor when compared to the other wavelet-based methods. Nevertheless, they are not competitive when compared to a fast precomputed vector quantizer. The benefits of applying a pre-processing stage, the Bias Adjusted Reordering, prior to the coding process in order to further exploit the spectral and/or spatial correlation when 2D techniques are employed, are also presented.

  19. Time Difference of Arrival (TDOA) Estimation Using Wavelet Based Denoising

    DTIC Science & Technology

    1999-03-01

    NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS TIME DIFFERENCE OF ARRIVAL (TDOA) ESTIMATION USING WAVELET BASED DENOISING by Unal Aktas...4. TITLE AND SUBTITLE TIME DIFFERENCE OF ARRIVAL (TDOA) ESTIMATION USING WAVELET BASED DENOISING 6. AUTHOR(S) Unal Aktas 7...difference of arrival (TDOA) method. The wavelet transform is used to increase the accuracy of TDOA estimation. Several denoising techniques based on

  20. Structured Light-Based 3D Reconstruction System for Plants.

    PubMed

    Nguyen, Thuy Tuong; Slaughter, David C; Max, Nelson; Maloof, Julin N; Sinha, Neelima

    2015-07-29

    Camera-based 3D reconstruction of physical objects is one of the most popular computer vision trends in recent years. Many systems have been built to model different real-world subjects, but there is lack of a completely robust system for plants. This paper presents a full 3D reconstruction system that incorporates both hardware structures (including the proposed structured light system to enhance textures on object surfaces) and software algorithms (including the proposed 3D point cloud registration and plant feature measurement). This paper demonstrates the ability to produce 3D models of whole plants created from multiple pairs of stereo images taken at different viewing angles, without the need to destructively cut away any parts of a plant. The ability to accurately predict phenotyping features, such as the number of leaves, plant height, leaf size and internode distances, is also demonstrated. Experimental results show that, for plants having a range of leaf sizes and a distance between leaves appropriate for the hardware design, the algorithms successfully predict phenotyping features in the target crops, with a recall of 0.97 and a precision of 0.89 for leaf detection and less than a 13-mm error for plant size, leaf size and internode distance.

  1. Structured Light-Based 3D Reconstruction System for Plants

    PubMed Central

    Nguyen, Thuy Tuong; Slaughter, David C.; Max, Nelson; Maloof, Julin N.; Sinha, Neelima

    2015-01-01

    Camera-based 3D reconstruction of physical objects is one of the most popular computer vision trends in recent years. Many systems have been built to model different real-world subjects, but there is lack of a completely robust system for plants.This paper presents a full 3D reconstruction system that incorporates both hardware structures (including the proposed structured light system to enhance textures on object surfaces) and software algorithms (including the proposed 3D point cloud registration and plant feature measurement). This paper demonstrates the ability to produce 3D models of whole plants created from multiple pairs of stereo images taken at different viewing angles, without the need to destructively cut away any parts of a plant. The ability to accurately predict phenotyping features, such as the number of leaves, plant height, leaf size and internode distances, is also demonstrated. Experimental results show that, for plants having a range of leaf sizes and a distance between leaves appropriate for the hardware design, the algorithms successfully predict phenotyping features in the target crops, with a recall of 0.97 and a precision of 0.89 for leaf detection and less than a 13-mm error for plant size, leaf size and internode distance. PMID:26230701

  2. Signal extrapolation based on wavelet representation

    NASA Astrophysics Data System (ADS)

    Xia, Xiang-Gen; Kuo, C.-C. Jay; Zhang, Zhen

    1993-11-01

    The Papoulis-Gerchberg (PG) algorithm is well known for band-limited signal extrapolation. We consider the generalization of the PG algorithm to signals in the wavelet subspaces in this research. The uniqueness of the extrapolation for continuous-time signals is examined, and sufficient conditions on signals and wavelet bases for the generalized PG (GPG) algorithm to converge are given. We also propose a discrete GPG algorithm for discrete-time signal extrapolation, and investigate its convergence. Numerical examples are given to illustrate the performance of the discrete GPG algorithm.

  3. Numerical Algorithms Based on Biorthogonal Wavelets

    NASA Technical Reports Server (NTRS)

    Ponenti, Pj.; Liandrat, J.

    1996-01-01

    Wavelet bases are used to generate spaces of approximation for the resolution of bidimensional elliptic and parabolic problems. Under some specific hypotheses relating the properties of the wavelets to the order of the involved operators, it is shown that an approximate solution can be built. This approximation is then stable and converges towards the exact solution. It is designed such that fast algorithms involving biorthogonal multi resolution analyses can be used to resolve the corresponding numerical problems. Detailed algorithms are provided as well as the results of numerical tests on partial differential equations defined on the bidimensional torus.

  4. Scalable still image coding based on wavelet

    NASA Astrophysics Data System (ADS)

    Yan, Yang; Zhang, Zhengbing

    2005-02-01

    The scalable image coding is an important objective of the future image coding technologies. In this paper, we present a kind of scalable image coding scheme based on wavelet transform. This method uses the famous EZW (Embedded Zero tree Wavelet) algorithm; we give a high-quality encoding to the ROI (region of interest) of the original image and a rough encoding to the rest. This method is applied well in limited memory space condition, and we encode the region of background according to the memory capacity. In this way, we can store the encoded image in limited memory space easily without losing its main information. Simulation results show it is effective.

  5. 3D geometry-based quantification of colocalizations in multichannel 3D microscopy images of human soft tissue tumors.

    PubMed

    Wörz, Stefan; Sander, Petra; Pfannmöller, Martin; Rieker, Ralf J; Joos, Stefan; Mechtersheimer, Gunhild; Boukamp, Petra; Lichter, Peter; Rohr, Karl

    2010-08-01

    We introduce a new model-based approach for automatic quantification of colocalizations in multichannel 3D microscopy images. The approach uses different 3D parametric intensity models in conjunction with a model fitting scheme to localize and quantify subcellular structures with high accuracy. The central idea is to determine colocalizations between different channels based on the estimated geometry of the subcellular structures as well as to differentiate between different types of colocalizations. A statistical analysis was performed to assess the significance of the determined colocalizations. This approach was used to successfully analyze about 500 three-channel 3D microscopy images of human soft tissue tumors and controls.

  6. Visual fatigue evaluation based on depth in 3D videos

    NASA Astrophysics Data System (ADS)

    Wang, Feng-jiao; Sang, Xin-zhu; Liu, Yangdong; Shi, Guo-zhong; Xu, Da-xiong

    2013-08-01

    In recent years, 3D technology has become an emerging industry. However, visual fatigue always impedes the development of 3D technology. In this paper we propose some factors affecting human perception of depth as new quality metrics. These factors are from three aspects of 3D video--spatial characteristics, temporal characteristics and scene movement characteristics. They play important roles for the viewer's visual perception. If there are many objects with a certain velocity and the scene changes fast, viewers will feel uncomfortable. In this paper, we propose a new algorithm to calculate the weight values of these factors and analyses their effect on visual fatigue.MSE (Mean Square Error) of different blocks is taken into consideration from the frame and inter-frame for 3D stereoscopic videos. The depth frame is divided into a number of blocks. There are overlapped and sharing pixels (at half of the block) in the horizontal and vertical direction. Ignoring edge information of objects in the image can be avoided. Then the distribution of all these data is indicated by kurtosis with regard of regions which human eye may mainly gaze at. Weight values can be gotten by the normalized kurtosis. When the method is used for individual depth, spatial variation can be achieved. When we use it in different frames between current and previous one, we can get temporal variation and scene movement variation. Three factors above are linearly combined, so we can get objective assessment value of 3D videos directly. The coefficients of three factors can be estimated based on the liner regression. At last, the experimental results show that the proposed method exhibits high correlation with subjective quality assessment results.

  7. 3-D model-based tracking for UAV indoor localization.

    PubMed

    Teulière, Céline; Marchand, Eric; Eck, Laurent

    2015-05-01

    This paper proposes a novel model-based tracking approach for 3-D localization. One main difficulty of standard model-based approach lies in the presence of low-level ambiguities between different edges. In this paper, given a 3-D model of the edges of the environment, we derive a multiple hypotheses tracker which retrieves the potential poses of the camera from the observations in the image. We also show how these candidate poses can be integrated into a particle filtering framework to guide the particle set toward the peaks of the distribution. Motivated by the UAV indoor localization problem where GPS signal is not available, we validate the algorithm on real image sequences from UAV flights.

  8. Embedded wavelet-based face recognition under variable position

    NASA Astrophysics Data System (ADS)

    Cotret, Pascal; Chevobbe, Stéphane; Darouich, Mehdi

    2015-02-01

    For several years, face recognition has been a hot topic in the image processing field: this technique is applied in several domains such as CCTV, electronic devices delocking and so on. In this context, this work studies the efficiency of a wavelet-based face recognition method in terms of subject position robustness and performance on various systems. The use of wavelet transform has a limited impact on the position robustness of PCA-based face recognition. This work shows, for a well-known database (Yale face database B*), that subject position in a 3D space can vary up to 10% of the original ROI size without decreasing recognition rates. Face recognition is performed on approximation coefficients of the image wavelet transform: results are still satisfying after 3 levels of decomposition. Furthermore, face database size can be divided by a factor 64 (22K with K = 3). In the context of ultra-embedded vision systems, memory footprint is one of the key points to be addressed; that is the reason why compression techniques such as wavelet transform are interesting. Furthermore, it leads to a low-complexity face detection stage compliant with limited computation resources available on such systems. The approach described in this work is tested on three platforms from a standard x86-based computer towards nanocomputers such as RaspberryPi and SECO boards. For K = 3 and a database with 40 faces, the execution mean time for one frame is 0.64 ms on a x86-based computer, 9 ms on a SECO board and 26 ms on a RaspberryPi (B model).

  9. 3-D measuring of engine camshaft based on machine vision

    NASA Astrophysics Data System (ADS)

    Qiu, Jianxin; Tan, Liang; Xu, Xiaodong

    2008-12-01

    The non-touch 3D measuring based on machine vision is introduced into camshaft precise measuring. Currently, because CCD 3-dimensional measuring can't meet requirements for camshaft's measuring precision, it's necessary to improve its measuring precision. In this paper, we put forward a method to improve the measuring method. A Multi-Character Match method based on the Polygonal Non-regular model is advanced with the theory of Corner Extraction and Corner Matching .This method has solved the problem of the matching difficulty and a low precision. In the measuring process, the use of the Coded marked Point method and Self-Character Match method can bring on this problem. The 3D measuring experiment on camshaft, which based on the Multi-Character Match method of the Polygonal Non-regular model, proves that the normal average measuring precision is increased to a new level less than 0.04mm in the point-clouds photo merge. This measuring method can effectively increase the 3D measuring precision of the binocular CCD.

  10. A new combined prior based reconstruction method for compressed sensing in 3D ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Uddin, Muhammad S.; Islam, Rafiqul; Tahtali, Murat; Lambert, Andrew J.; Pickering, Mark R.

    2015-03-01

    Ultrasound (US) imaging is one of the most popular medical imaging modalities, with 3D US imaging gaining popularity recently due to its considerable advantages over 2D US imaging. However, as it is limited by long acquisition times and the huge amount of data processing it requires, methods for reducing these factors have attracted considerable research interest. Compressed sensing (CS) is one of the best candidates for accelerating the acquisition rate and reducing the data processing time without degrading image quality. However, CS is prone to introduce noise-like artefacts due to random under-sampling. To address this issue, we propose a combined prior-based reconstruction method for 3D US imaging. A Laplacian mixture model (LMM) constraint in the wavelet domain is combined with a total variation (TV) constraint to create a new regularization regularization prior. An experimental evaluation conducted to validate our method using synthetic 3D US images shows that it performs better than other approaches in terms of both qualitative and quantitative measures.

  11. Projection-slice theorem based 2D-3D registration

    NASA Astrophysics Data System (ADS)

    van der Bom, M. J.; Pluim, J. P. W.; Homan, R.; Timmer, J.; Bartels, L. W.

    2007-03-01

    In X-ray guided procedures, the surgeon or interventionalist is dependent on his or her knowledge of the patient's specific anatomy and the projection images acquired during the procedure by a rotational X-ray source. Unfortunately, these X-ray projections fail to give information on the patient's anatomy in the dimension along the projection axis. It would be very profitable to provide the surgeon or interventionalist with a 3D insight of the patient's anatomy that is directly linked to the X-ray images acquired during the procedure. In this paper we present a new robust 2D-3D registration method based on the Projection-Slice Theorem. This theorem gives us a relation between the pre-operative 3D data set and the interventional projection images. Registration is performed by minimizing a translation invariant similarity measure that is applied to the Fourier transforms of the images. The method was tested by performing multiple exhaustive searches on phantom data of the Circle of Willis and on a post-mortem human skull. Validation was performed visually by comparing the test projections to the ones that corresponded to the minimal value of the similarity measure. The Projection-Slice Theorem Based method was shown to be very effective and robust, and provides capture ranges up to 62 degrees. Experiments have shown that the method is capable of retrieving similar results when translations are applied to the projection images.

  12. 3D shape measurement with phase correlation based fringe projection

    NASA Astrophysics Data System (ADS)

    Kühmstedt, Peter; Munckelt, Christoph; Heinze, Matthias; Bräuer-Burchardt, Christian; Notni, Gunther

    2007-06-01

    Here we propose a method for 3D shape measurement by means of phase correlation based fringe projection in a stereo arrangement. The novelty in the approach is characterized by following features. Correlation between phase values of the images of two cameras is used for the co-ordinate calculation. This work stands in contrast to the sole usage of phase values (phasogrammetry) or classical triangulation (phase values and image co-ordinates - camera raster values) for the determination of the co-ordinates. The method's main advantage is the insensitivity of the 3D-coordinates from the absolute phase values. Thus it prevents errors in the determination of the co-ordinates and improves robustness in areas with interreflections artefacts and inhomogeneous regions of intensity. A technical advantage is the fact that the accuracy of the 3D co-ordinates does not depend on the projection resolution. Thus the achievable quality of the 3D co-ordinates can be selectively improved by the use of high quality camera lenses and can participate in improvements in modern camera technologies. The presented new solution of the stereo based fringe projection with phase correlation makes a flexible, errortolerant realization of measuring systems within different applications like quality control, rapid prototyping, design and CAD/CAM possible. In the paper the phase correlation method will be described in detail. Furthermore, different realizations will be shown, i.e. a mobile system for the measurement of large objects and an endoscopic like system for CAD/CAM in dental industry.

  13. Abdominal aortic aneurysm imaging with 3-D ultrasound: 3-D-based maximum diameter measurement and volume quantification.

    PubMed

    Long, A; Rouet, L; Debreuve, A; Ardon, R; Barbe, C; Becquemin, J P; Allaire, E

    2013-08-01

    The clinical reliability of 3-D ultrasound imaging (3-DUS) in quantification of abdominal aortic aneurysm (AAA) was evaluated. B-mode and 3-DUS images of AAAs were acquired for 42 patients. AAAs were segmented. A 3-D-based maximum diameter (Max3-D) and partial volume (Vol30) were defined and quantified. Comparisons between 2-D (Max2-D) and 3-D diameters and between orthogonal acquisitions were performed. Intra- and inter-observer reproducibility was evaluated. Intra- and inter-observer coefficients of repeatability (CRs) were less than 5.18 mm for Max3-D. Intra-observer and inter-observer CRs were respectively less than 6.16 and 8.71 mL for Vol30. The mean of normalized errors of Vol30 was around 7%. Correlation between Max2-D and Max3-D was 0.988 (p < 0.0001). Max3-D and Vol30 were not influenced by a probe rotation of 90°. Use of 3-DUS to quantify AAA is a new approach in clinical practice. The present study proposed and evaluated dedicated parameters. Their reproducibility makes the technique clinically reliable.

  14. A flexible fast 3D profilometry based on modulation measurement

    NASA Astrophysics Data System (ADS)

    Dou, Yunfu; Su, Xianyu; Chen, Yanfei; Wang, Ying

    2011-03-01

    This paper proposes a flexible fast profilometry based on modulation measurement. Two orthogonal gratings through a beam splitter are vertically projected on an object surface, and the measured object is placed between the imaging planes of the two gratings. Then the image of the object surface modulated by the orthogonal gratings can be obtained by a CCD camera in the same direction as the grating projection. This image is processed by the operations consisting of performing the Fourier transform, spatial frequency filtering and inverse Fourier transform. Using the modulation distributions of two grating patterns, we can reconstruct the 3D shape of the object. In the measurement process, we only need to capture one fringe pattern, so it is faster than the MMP and remains the advantages of it. In the article, the principle of this method, the setup of the measurement system, some simulations and primary experiment results are given. The simulative and experimental result proves it can restore the 3D shape of the complex object fast and comparatively accurate. Because only one fringe pattern is needed in the testing, our method has a promising extensive application prospect in real-time acquiring and dynamic measurement of 3D data of complex objects.

  15. Neuromorphic Event-Based 3D Pose Estimation

    PubMed Central

    Reverter Valeiras, David; Orchard, Garrick; Ieng, Sio-Hoi; Benosman, Ryad B.

    2016-01-01

    Pose estimation is a fundamental step in many artificial vision tasks. It consists of estimating the 3D pose of an object with respect to a camera from the object's 2D projection. Current state of the art implementations operate on images. These implementations are computationally expensive, especially for real-time applications. Scenes with fast dynamics exceeding 30–60 Hz can rarely be processed in real-time using conventional hardware. This paper presents a new method for event-based 3D object pose estimation, making full use of the high temporal resolution (1 μs) of asynchronous visual events output from a single neuromorphic camera. Given an initial estimate of the pose, each incoming event is used to update the pose by combining both 3D and 2D criteria. We show that the asynchronous high temporal resolution of the neuromorphic camera allows us to solve the problem in an incremental manner, achieving real-time performance at an update rate of several hundreds kHz on a conventional laptop. We show that the high temporal resolution of neuromorphic cameras is a key feature for performing accurate pose estimation. Experiments are provided showing the performance of the algorithm on real data, including fast moving objects, occlusions, and cases where the neuromorphic camera and the object are both in motion. PMID:26834547

  16. An endoscopic 3D scanner based on structured light.

    PubMed

    Schmalz, Christoph; Forster, Frank; Schick, Anton; Angelopoulou, Elli

    2012-07-01

    We present a new endoscopic 3D scanning system based on Single Shot Structured Light. The proposed design makes it possible to build an extremely small scanner. The sensor head contains a catadioptric camera and a pattern projection unit. The paper describes the working principle and calibration procedure of the sensor. The prototype sensor head has a diameter of only 3.6mm and a length of 14mm. It is mounted on a flexible shaft. The scanner is designed for tubular cavities and has a cylindrical working volume of about 30mm length and 30mm diameter. It acquires 3D video at 30 frames per second and typically generates approximately 5000 3D points per frame. By design, the resolution varies over the working volume, but is generally better than 200μm. A prototype scanner has been built and is evaluated in experiments with phantoms and biological samples. The recorded average error on a known test object was 92μm.

  17. Facial-paralysis diagnostic system based on 3D reconstruction

    NASA Astrophysics Data System (ADS)

    Khairunnisaa, Aida; Basah, Shafriza Nisha; Yazid, Haniza; Basri, Hassrizal Hassan; Yaacob, Sazali; Chin, Lim Chee

    2015-05-01

    The diagnostic process of facial paralysis requires qualitative assessment for the classification and treatment planning. This result is inconsistent assessment that potential affect treatment planning. We developed a facial-paralysis diagnostic system based on 3D reconstruction of RGB and depth data using a standard structured-light camera - Kinect 360 - and implementation of Active Appearance Models (AAM). We also proposed a quantitative assessment for facial paralysis based on triangular model. In this paper, we report on the design and development process, including preliminary experimental results. Our preliminary experimental results demonstrate the feasibility of our quantitative assessment system to diagnose facial paralysis.

  18. Surface topography study of prepared 3D printed moulds via 3D printer for silicone elastomer based nasal prosthesis

    NASA Astrophysics Data System (ADS)

    Abdullah, Abdul Manaf; Din, Tengku Noor Daimah Tengku; Mohamad, Dasmawati; Rahim, Tuan Noraihan Azila Tuan; Akil, Hazizan Md; Rajion, Zainul Ahmad

    2016-12-01

    Conventional prosthesis fabrication is highly depends on the hand creativity of laboratory technologist. The development in 3D printing technology offers a great help in fabricating affordable and fast yet esthetically acceptable prostheses. This study was conducted to discover the potential of 3D printed moulds for indirect silicone elastomer based nasal prosthesis fabrication. Moulds were designed using computer aided design (CAD) software (Solidworks, USA) and converted into the standard tessellation language (STL) file. Three moulds with layer thickness of 0.1, 0.2 and 0.3mm were printed utilizing polymer filament based 3D printer (Makerbot Replicator 2X, Makerbot, USA). Another one mould was printed utilizing liquid resin based 3D printer (Objet 30 Scholar, Stratasys, USA) as control. The printed moulds were then used to fabricate maxillofacial silicone specimens (n=10)/mould. Surface profilometer (Surfcom Flex, Accretech, Japan), digital microscope (KH77000, Hirox, USA) and scanning electron microscope (Quanta FEG 450, Fei, USA) were used to measure the surface roughness as well as the topological properties of fabricated silicone. Statistical analysis of One-Way ANOVA was employed to compare the surface roughness of the fabricated silicone elastomer. Result obtained demonstrated significant differences in surface roughness of the fabricated silicone (p<0.01). Further post hoc analysis also revealed significant differences in silicone fabricated using different 3D printed moulds (p<0.01). A 3D printed mould was successfully prepared and characterized. With surface topography that could be enhanced, inexpensive and rapid mould fabrication techniques, polymer filament based 3D printer is potential for indirect silicone elastomer based nasal prosthesis fabrication.

  19. Study on the FOG's signal based on wavelet

    NASA Astrophysics Data System (ADS)

    Tang, Ji-qiang; Fang, Jian-cheng; Zhang, Yan-shun

    2006-11-01

    In order to study on the fiber optical gyro (abbreviated as FOG) signal based on wavelet, this paper researches the FOG signal drift model and the properties of wavelet analyzed noise, introduces the wavelet filtering method, wavelet base selection, soft and hard threshold value de-noising algorithm and compulsive filtering based on The Haar wavelet. These threshold value filtering results of both of the soft and of the hard threshold value for the same wavelet base of db4 with the same Donoho threshold values and these results of compulsive filtering based on The Haar wavelet and db4 wavelet are presented also in this paper and then these main conclusions based on foregoing analysis are reached: Larger the resolving scale is, the filtering effect is more perfect. The soft threshold value filtering effect is better than that of the hard threshold value filtering at the cost of calculation when the threshold value is same. The zero shift of the compulsive filtering is least when both the wavelet and the resolving scale are same for these filtering methods. For the compulsive filtering with same wavelets, the filtering effect of Harr is better than that of db4 and the calculation of the former is fewer. Finally the author point out that applying the compulsive filtering with the Harr wavelet base and suitable resolving scale to the signal processing of FOG be helpful for the FOG's design and manufacturing.

  20. Modeling approaches for ligand-based 3D similarity.

    PubMed

    Tresadern, Gary; Bemporad, Daniele

    2010-10-01

    3D ligand-based similarity approaches are widely used in the early phases of drug discovery for tasks such as hit finding by virtual screening or compound design with quantitative structure-activity relationships. Here in we review widely used software for performing such tasks. Some techniques are based on relatively mature technology, shape-based similarity for instance. Typically, these methods remained in the realm of the expert user, the experienced modeler. However, advances in implementation and speed have improved usability and allow these methods to be applied to databases comprising millions of compounds. There are now many reports of such methods impacting drug-discovery projects. As such, the medicinal chemistry community has become the intended market for some of these new tools, yet they may consider the wide array and choice of approaches somewhat disconcerting. Each method has subtle differences and is better suited to certain tasks than others. In this article we review some of the widely used computational methods via application, provide straightforward background on the underlying theory and provide examples for the interested reader to pursue in more detail. In the new era of preclinical drug discovery there will be ever more pressure to move faster and more efficiently, and computational approaches based on 3D ligand similarity will play an increasing role in in this process.

  1. Virtual reality 3D headset based on DMD light modulators

    SciTech Connect

    Bernacki, Bruce E.; Evans, Allan; Tang, Edward

    2014-06-13

    We present the design of an immersion-type 3D headset suitable for virtual reality applications based upon digital micro-mirror devices (DMD). Our approach leverages silicon micro mirrors offering 720p resolution displays in a small form-factor. Supporting chip sets allow rapid integration of these devices into wearable displays with high resolution and low power consumption. Applications include night driving, piloting of UAVs, fusion of multiple sensors for pilots, training, vision diagnostics and consumer gaming. Our design is described in which light from the DMD is imaged to infinity and the user’s own eye lens forms a real image on the user’s retina.

  2. Wavelet-Based Image Enhancement in X-Ray Imaging and Tomography

    NASA Astrophysics Data System (ADS)

    Bronnikov, Andrei V.; Duifhuis, Gerrit

    1998-07-01

    We consider an application of the wavelet transform to image processing in x-ray imaging and three-dimensional (3-D) tomography aimed at industrial inspection. Our experimental setup works in two operational modes digital radiography and 3-D cone-beam tomographic data acquisition. Although the x-ray images measured have a large dynamic range and good spatial resolution, their noise properties and contrast are often not optimal. To enhance the images, we suggest applying digital image processing by using wavelet-based algorithms and consider the wavelet-based multiscale edge representation in the framework of the Mallat and Zhong approach IEEE Trans. Pattern Anal. Mach. Intell. 14, 710 (1992) . A contrast-enhancement method by use of equalization of the multiscale edges is suggested. Several denoising algorithms based on modifying the modulus and the phase of the multiscale gradients and several contrast-enhancement techniques applying linear and nonlinear multiscale edge stretching are described and compared by use of experimental data. We propose the use of a filter bank of wavelet-based reconstruction filters for the filtered-backprojection reconstruction algorithm. Experimental results show a considerable increase in the performance of the whole x-ray imaging system for both radiographic and tomographic modes in the case of the application of the wavelet-based image-processing algorithms.

  3. Fast vision-based catheter 3D reconstruction.

    PubMed

    Moradi Dalvand, Mohsen; Nahavandi, Saeid; Howe, Robert D

    2016-07-21

    Continuum robots offer better maneuverability and inherent compliance and are well-suited for surgical applications as catheters, where gentle interaction with the environment is desired. However, sensing their shape and tip position is a challenge as traditional sensors can not be employed in the way they are in rigid robotic manipulators. In this paper, a high speed vision-based shape sensing algorithm for real-time 3D reconstruction of continuum robots based on the views of two arbitrary positioned cameras is presented. The algorithm is based on the closed-form analytical solution of the reconstruction of quadratic curves in 3D space from two arbitrary perspective projections. High-speed image processing algorithms are developed for the segmentation and feature extraction from the images. The proposed algorithms are experimentally validated for accuracy by measuring the tip position, length and bending and orientation angles for known circular and elliptical catheter shaped tubes. Sensitivity analysis is also carried out to evaluate the robustness of the algorithm. Experimental results demonstrate good accuracy (maximum errors of  ±0.6 mm and  ±0.5 deg), performance (200 Hz), and robustness (maximum absolute error of 1.74 mm, 3.64 deg for the added noises) of the proposed high speed algorithms.

  4. Fast vision-based catheter 3D reconstruction

    NASA Astrophysics Data System (ADS)

    Moradi Dalvand, Mohsen; Nahavandi, Saeid; Howe, Robert D.

    2016-07-01

    Continuum robots offer better maneuverability and inherent compliance and are well-suited for surgical applications as catheters, where gentle interaction with the environment is desired. However, sensing their shape and tip position is a challenge as traditional sensors can not be employed in the way they are in rigid robotic manipulators. In this paper, a high speed vision-based shape sensing algorithm for real-time 3D reconstruction of continuum robots based on the views of two arbitrary positioned cameras is presented. The algorithm is based on the closed-form analytical solution of the reconstruction of quadratic curves in 3D space from two arbitrary perspective projections. High-speed image processing algorithms are developed for the segmentation and feature extraction from the images. The proposed algorithms are experimentally validated for accuracy by measuring the tip position, length and bending and orientation angles for known circular and elliptical catheter shaped tubes. Sensitivity analysis is also carried out to evaluate the robustness of the algorithm. Experimental results demonstrate good accuracy (maximum errors of  ±0.6 mm and  ±0.5 deg), performance (200 Hz), and robustness (maximum absolute error of 1.74 mm, 3.64 deg for the added noises) of the proposed high speed algorithms.

  5. Integral imaging based 3D display of holographic data.

    PubMed

    Yöntem, Ali Özgür; Onural, Levent

    2012-10-22

    We propose a method and present applications of this method that converts a diffraction pattern into an elemental image set in order to display them on an integral imaging based display setup. We generate elemental images based on diffraction calculations as an alternative to commonly used ray tracing methods. Ray tracing methods do not accommodate the interference and diffraction phenomena. Our proposed method enables us to obtain elemental images from a holographic recording of a 3D object/scene. The diffraction pattern can be either numerically generated data or digitally acquired optical data. The method shows the connection between a hologram (diffraction pattern) and an elemental image set of the same 3D object. We showed three examples, one of which is the digitally captured optical diffraction tomography data of an epithelium cell. We obtained optical reconstructions with our integral imaging display setup where we used a digital lenslet array. We also obtained numerical reconstructions, again by using the diffraction calculations, for comparison. The digital and optical reconstruction results are in good agreement.

  6. EEG-based usability assessment of 3D shutter glasses

    NASA Astrophysics Data System (ADS)

    Wenzel, Markus A.; Schultze-Kraft, Rafael; Meinecke, Frank C.; Cardinaux, Fabien; Kemp, Thomas; Müller, Klaus-Robert; Curio, Gabriel; Blankertz, Benjamin

    2016-02-01

    Objective. Neurotechnology can contribute to the usability assessment of products by providing objective measures of neural workload and can uncover usability impediments that are not consciously perceived by test persons. In this study, the neural processing effort imposed on the viewer of 3D television by shutter glasses was quantified as a function of shutter frequency. In particular, we sought to determine the critical shutter frequency at which the ‘neural flicker’ vanishes, such that visual fatigue due to this additional neural effort can be prevented by increasing the frequency of the system. Approach. Twenty-three participants viewed an image through 3D shutter glasses, while multichannel electroencephalogram (EEG) was recorded. In total ten shutter frequencies were employed, selected individually for each participant to cover the range below, at and above the threshold of flicker perception. The source of the neural flicker correlate was extracted using independent component analysis and the flicker impact on the visual cortex was quantified by decoding the state of the shutter from the EEG. Main Result. Effects of the shutter glasses were traced in the EEG up to around 67 Hz—about 20 Hz over the flicker perception threshold—and vanished at the subsequent frequency level of 77 Hz. Significance. The impact of the shutter glasses on the visual cortex can be detected by neurotechnology even when a flicker is not reported by the participants. Potential impact. Increasing the shutter frequency from the usual 50 Hz or 60 Hz to 77 Hz reduces the risk of visual fatigue and thus improves shutter-glass-based 3D usability.

  7. Appearance-based color face recognition with 3D model

    NASA Astrophysics Data System (ADS)

    Wang, Chengzhang; Bai, Xiaoming

    2013-03-01

    Appearance-based face recognition approaches explore color cues of face images, i.e. grey or color information for recognition task. They first encode color face images, and then extract facial features for classification. Similar to conventional singular value decomposition, hypercomplex matrix also exists singular value decomposition on hypercomplex field. In this paper, a novel color face recognition approach based on hypercomplex singular value decomposition is proposed. The approach employs hypercomplex to encode color face information of different channels simultaneously. Hypercomplex singular value decomposition is utilized then to compute the basis vectors of the color face subspace. To improve learning efficiency of the algorithm, 3D active deformable model is exploited to generate virtual face images. Color face samples are projected onto the subspace and projection coefficients are utilized as facial features. Experimental results on CMU PIE face database verify the effectiveness of the proposed approach.

  8. Spatio-temporal validation of long-term 3D hydrological simulations of a forested catchment using empirical orthogonal functions and wavelet coherence analysis

    NASA Astrophysics Data System (ADS)

    Fang, Zhufeng; Bogena, Heye; Kollet, Stefan; Koch, Julian; Vereecken, Harry

    2015-10-01

    Soil moisture plays a key role in the water and energy balance in soil, vegetation and atmosphere systems. According to Wood et al. (2011) there is a grand need to increase global-scale hyper-resolution water-energy-biogeochemistry land surface modelling capabilities. These modelling capabilities should also recognize epistemic uncertainties, as well as the nonlinearity and hysteresis in its dynamics. Unfortunately, it is not clear how to parameterize hydrological processes as a function of scale, and how to test deterministic models with regard to epistemic uncertainties. In this study, high resolution long-term simulations were conducted in the highly instrumented TERENO hydrological observatory of the Wüstebach catchment. Soil hydraulic parameters were derived using inverse modelling with the Hydrus-1D model using the global optimization scheme SCE-UA and soil moisture data from a wireless soil moisture sensor network. The estimated parameters were then used for 3D simulations of water transport using the integrated parallel simulation platform ParFlow-CLM. The simulated soil moisture dynamics, as well as evapotranspiration (ET) and runoff, were compared with long-term field observations to illustrate how well the model was able to reproduce the water budget dynamics. We investigated different anisotropies of hydraulic conductivity to analyze how fast lateral flow processes above the underlying bedrock affect the simulation results. For a detail investigation of the model results we applied the empirical orthogonal function (EOF) and wavelet coherence methods. The EOF analysis of temporal-spatial patterns of simulated and observed soil moisture revealed that introduction of heterogeneity in the soil porosity effectively improves estimates of soil moisture patterns. Our wavelet coherence analysis indicates that wet and dry seasons have significant effect on temporal correlation between observed and simulated soil moisture and ET. Our study demonstrates the

  9. 3D modeling based on CityEngine

    NASA Astrophysics Data System (ADS)

    Jia, Guangyin; Liao, Kaiju

    2017-03-01

    Currently, there are many 3D modeling softwares, like 3DMAX, AUTOCAD, and more populous BIM softwares represented by REVIT. CityEngine modeling software introduced in this paper can fully utilize the existing GIS data and combine other built models to make 3D modeling on internal and external part of buildings in a rapid and batch manner, so as to improve the 3D modeling efficiency.

  10. Wavelet-based functional mixed models

    PubMed Central

    Morris, Jeffrey S.; Carroll, Raymond J.

    2009-01-01

    Summary Increasingly, scientific studies yield functional data, in which the ideal units of observation are curves and the observed data consist of sets of curves that are sampled on a fine grid. We present new methodology that generalizes the linear mixed model to the functional mixed model framework, with model fitting done by using a Bayesian wavelet-based approach. This method is flexible, allowing functions of arbitrary form and the full range of fixed effects structures and between-curve covariance structures that are available in the mixed model framework. It yields nonparametric estimates of the fixed and random-effects functions as well as the various between-curve and within-curve covariance matrices. The functional fixed effects are adaptively regularized as a result of the non-linear shrinkage prior that is imposed on the fixed effects’ wavelet coefficients, and the random-effect functions experience a form of adaptive regularization because of the separately estimated variance components for each wavelet coefficient. Because we have posterior samples for all model quantities, we can perform pointwise or joint Bayesian inference or prediction on the quantities of the model. The adaptiveness of the method makes it especially appropriate for modelling irregular functional data that are characterized by numerous local features like peaks. PMID:19759841

  11. Pedestrian detection based on redundant wavelet transform

    NASA Astrophysics Data System (ADS)

    Huang, Lin; Ji, Liping; Hu, Ping; Yang, Tiejun

    2016-10-01

    Intelligent video surveillance is to analysis video or image sequences captured by a fixed or mobile surveillance camera, including moving object detection, segmentation and recognition. By using it, we can be notified immediately in an abnormal situation. Pedestrian detection plays an important role in an intelligent video surveillance system, and it is also a key technology in the field of intelligent vehicle. So pedestrian detection has very vital significance in traffic management optimization, security early warn and abnormal behavior detection. Generally, pedestrian detection can be summarized as: first to estimate moving areas; then to extract features of region of interest; finally to classify using a classifier. Redundant wavelet transform (RWT) overcomes the deficiency of shift variant of discrete wavelet transform, and it has better performance in motion estimation when compared to discrete wavelet transform. Addressing the problem of the detection of multi-pedestrian with different speed, we present an algorithm of pedestrian detection based on motion estimation using RWT, combining histogram of oriented gradients (HOG) and support vector machine (SVM). Firstly, three intensities of movement (IoM) are estimated using RWT and the corresponding areas are segmented. According to the different IoM, a region proposal (RP) is generated. Then, the features of a RP is extracted using HOG. Finally, the features are fed into a SVM trained by pedestrian databases and the final detection results are gained. Experiments show that the proposed algorithm can detect pedestrians accurately and efficiently.

  12. Hydrogel-based reinforcement of 3D bioprinted constructs

    PubMed Central

    Levato, R; Peiffer, Q C; de Ruijter, M; Hennink, W E; Vermonden, T; Malda, J

    2016-01-01

    Progress within the field of biofabrication is hindered by a lack of suitable hydrogel formulations. Here, we present a novel approach based on a hybrid printing technique to create cellularized 3D printed constructs. The hybrid bioprinting strategy combines a reinforcing gel for mechanical support with a bioink to provide a cytocompatible environment. In comparison with thermoplastics such as є-polycaprolactone, the hydrogel-based reinforcing gel platform enables printing at cell-friendly temperatures, targets the bioprinting of softer tissues and allows for improved control over degradation kinetics. We prepared amphiphilic macromonomers based on poloxamer that form hydrolysable, covalently cross-linked polymer networks. Dissolved at a concentration of 28.6%w/w in water, it functions as reinforcing gel, while a 5%w/w gelatin-methacryloyl based gel is utilized as bioink. This strategy allows for the creation of complex structures, where the bioink provides a cytocompatible environment for encapsulated cells. Cell viability of equine chondrocytes encapsulated within printed constructs remained largely unaffected by the printing process. The versatility of the system is further demonstrated by the ability to tune the stiffness of printed constructs between 138 and 263 kPa, as well as to tailor the degradation kinetics of the reinforcing gel from several weeks up to more than a year. PMID:27431861

  13. Energy harvesting “3-D knitted spacer” based piezoelectric textiles

    NASA Astrophysics Data System (ADS)

    Anand, S.; Soin, N.; Shah, T. H.; Siores, E.

    2016-07-01

    The piezoelectric effect in Poly(vinylidene fluoride), PVDF, was discovered over four decades ago and since then, significant work has been carried out aiming at the production of high p-phase fibres and their integration into fabric structures for energy harvesting. However, little work has been done in the area of production of “true piezoelectric fabric structures” based on flexible polymeric materials such as PVDF. In this work, we demonstrate “3-D knitted spacer” technology based all-fibre piezoelectric fabrics as power generators and energy harvesters. The knitted single-structure piezoelectric generator consists of high p-phase (~80%) piezoelectric PVDF monofilaments as the spacer yarn interconnected between silver (Ag) coated polyamide multifilament yarn layers acting as the top and bottom electrodes. The novel and unique textile structure provides an output power density in the range of 1.105.10 gWcm-2 at applied impact pressures in the range of 0.02-0.10 MPa, thus providing significantly higher power outputs and efficiencies over the existing 2-D woven and nonwoven piezoelectric structures. The high energy efficiency, mechanical durability and comfort of the soft, flexible and all-fibre based power generator is highly attractive for a variety of potential applications such as wearable electronic systems and energy harvesters charged from ambient environment or by human movement.

  14. Cloud Based Web 3d GIS Taiwan Platform

    NASA Astrophysics Data System (ADS)

    Tsai, W.-F.; Chang, J.-Y.; Yan, S. Y.; Chen, B.

    2011-09-01

    This article presents the status of the web 3D GIS platform, which has been developed in the National Applied Research Laboratories. The purpose is to develop a global earth observation 3D GIS platform for applications to disaster monitoring and assessment in Taiwan. For quick response to preliminary and detailed assessment after a natural disaster occurs, the web 3D GIS platform is useful to access, transfer, integrate, display and analyze the multi-scale huge data following the international OGC standard. The framework of cloud service for data warehousing management and efficiency enhancement using VMWare is illustrated in this article.

  15. Wavelet-Based Multiresolution Analyses of Signals

    DTIC Science & Technology

    1992-06-01

    classification. Some signals, notably those of a transient nature, are inherently difficult to analyze with these traditional tools. The Discrete Wavelet Transform has...scales. This thesis investigates dyadic discrete wavelet decompositions of signals. A new multiphase wavelet transform is proposed and investigated. The

  16. Fingerprint spoof detection using wavelet based local binary pattern

    NASA Astrophysics Data System (ADS)

    Kumpituck, Supawan; Li, Dongju; Kunieda, Hiroaki; Isshiki, Tsuyoshi

    2017-02-01

    In this work, a fingerprint spoof detection method using an extended feature, namely Wavelet-based Local Binary Pattern (Wavelet-LBP) is introduced. Conventional wavelet-based methods calculate wavelet energy of sub-band images as the feature for discrimination while we propose to use Local Binary Pattern (LBP) operation to capture the local appearance of the sub-band images instead. The fingerprint image is firstly decomposed by two-dimensional discrete wavelet transform (2D-DWT), and then LBP is applied on the derived wavelet sub-band images. Furthermore, the extracted features are used to train Support Vector Machine (SVM) classifier to create the model for classifying the fingerprint images into genuine and spoof. Experiments that has been done on Fingerprint Liveness Detection Competition (LivDet) datasets show the improvement of the fingerprint spoof detection by using the proposed feature.

  17. Gis-Based Smart Cartography Using 3d Modeling

    NASA Astrophysics Data System (ADS)

    Malinverni, E. S.; Tassetti, A. N.

    2013-08-01

    3D City Models have evolved to be important tools for urban decision processes and information systems, especially in planning, simulation, analysis, documentation and heritage management. On the other hand existing and in use numerical cartography is often not suitable to be used in GIS because not geometrically and topologically correctly structured. The research aim is to 3D structure and organize a numeric cartography for GIS and turn it into CityGML standardized features. The work is framed around a first phase of methodological analysis aimed to underline which existing standard (like ISO and OGC rules) can be used to improve the quality requirement of a cartographic structure. Subsequently, from this technical specifics, it has been investigated the translation in formal contents, using an owner interchange software (SketchUp), to support some guide lines implementations to generate a GIS3D structured in GML3. It has been therefore predisposed a test three-dimensional numerical cartography (scale 1:500, generated from range data captured by 3D laser scanner), tested on its quality according to the previous standard and edited when and where necessary. Cad files and shapefiles are converted into a final 3D model (Google SketchUp model) and then exported into a 3D city model (CityGML LoD1/LoD2). The GIS3D structure has been managed in a GIS environment to run further spatial analysis and energy performance estimate, not achievable in a 2D environment. In particular geometrical building parameters (footprint, volume etc.) are computed and building envelop thermal characteristics are derived from. Lastly, a simulation is carried out to deal with asbestos and home renovating charges and show how the built 3D city model can support municipal managers with risk diagnosis of the present situation and development of strategies for a sustainable redevelop.

  18. Wavelet-based verification of the quantitative precipitation forecast

    NASA Astrophysics Data System (ADS)

    Yano, Jun-Ichi; Jakubiak, Bogumil

    2016-06-01

    This paper explores the use of wavelets for spatial verification of quantitative precipitation forecasts (QPF), and especially the capacity of wavelets to provide both localization and scale information. Two 24-h forecast experiments using the two versions of the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) on 22 August 2010 over Poland are used to illustrate the method. Strong spatial localizations and associated intermittency of the precipitation field make verification of QPF difficult using standard statistical methods. The wavelet becomes an attractive alternative, because it is specifically designed to extract spatially localized features. The wavelet modes are characterized by the two indices for the scale and the localization. Thus, these indices can simply be employed for characterizing the performance of QPF in scale and localization without any further elaboration or tunable parameters. Furthermore, spatially-localized features can be extracted in wavelet space in a relatively straightforward manner with only a weak dependence on a threshold. Such a feature may be considered an advantage of the wavelet-based method over more conventional "object" oriented verification methods, as the latter tend to represent strong threshold sensitivities. The present paper also points out limits of the so-called "scale separation" methods based on wavelets. Our study demonstrates how these wavelet-based QPF verifications can be performed straightforwardly. Possibilities for further developments of the wavelet-based methods, especially towards a goal of identifying a weak physical process contributing to forecast error, are also pointed out.

  19. Open-GL-based stereo system for 3D measurements

    NASA Astrophysics Data System (ADS)

    Boochs, Frank; Gehrhoff, Anja; Neifer, Markus

    2000-05-01

    A stereo system designed and used for the measurement of 3D- coordinates within metric stereo image pairs will be presented. First, the motivation for the development is shown, allowing to evaluate stereo images. As the use and availability of metric images of digital type rapidly increases corresponding equipment for the measuring process is needed. Systems which have been developed up to now are either very special ones, founded on high end graphics workstations with an according pricing or simple ones with restricted measuring functionality. A new conception will be shown, avoiding special high end graphics hardware but providing the measuring functionality required. The presented stereo system is based on PC-hardware equipped with a graphic board and uses an object oriented programming technique. The specific needs of a measuring system are shown and the corresponding requirements which have to be met by the system. The key role of OpenGL is described, which supplies some elementary graphic functions, being directly supported by graphic boards and thus provides the performance needed. Further important aspects as modularity and hardware independence and their value for the solution are shown. Finally some sample functions concerned with image display and handling are presented in more detail.

  20. A Simple Quality Assessment Index for Stereoscopic Images Based on 3D Gradient Magnitude

    PubMed Central

    Wang, Shanshan; Shao, Feng; Li, Fucui; Yu, Mei; Jiang, Gangyi

    2014-01-01

    We present a simple quality assessment index for stereoscopic images based on 3D gradient magnitude. To be more specific, we construct 3D volume from the stereoscopic images across different disparity spaces and calculate pointwise 3D gradient magnitude similarity (3D-GMS) along three horizontal, vertical, and viewpoint directions. Then, the quality score is obtained by averaging the 3D-GMS scores of all points in the 3D volume. Experimental results on four publicly available 3D image quality assessment databases demonstrate that, in comparison with the most related existing methods, the devised algorithm achieves high consistency alignment with subjective assessment. PMID:25133265

  1. Automated 3D renal segmentation based on image partitioning

    NASA Astrophysics Data System (ADS)

    Yeghiazaryan, Varduhi; Voiculescu, Irina D.

    2016-03-01

    Despite several decades of research into segmentation techniques, automated medical image segmentation is barely usable in a clinical context, and still at vast user time expense. This paper illustrates unsupervised organ segmentation through the use of a novel automated labelling approximation algorithm followed by a hypersurface front propagation method. The approximation stage relies on a pre-computed image partition forest obtained directly from CT scan data. We have implemented all procedures to operate directly on 3D volumes, rather than slice-by-slice, because our algorithms are dimensionality-independent. The results picture segmentations which identify kidneys, but can easily be extrapolated to other body parts. Quantitative analysis of our automated segmentation compared against hand-segmented gold standards indicates an average Dice similarity coefficient of 90%. Results were obtained over volumes of CT data with 9 kidneys, computing both volume-based similarity measures (such as the Dice and Jaccard coefficients, true positive volume fraction) and size-based measures (such as the relative volume difference). The analysis considered both healthy and diseased kidneys, although extreme pathological cases were excluded from the overall count. Such cases are difficult to segment both manually and automatically due to the large amplitude of Hounsfield unit distribution in the scan, and the wide spread of the tumorous tissue inside the abdomen. In the case of kidneys that have maintained their shape, the similarity range lies around the values obtained for inter-operator variability. Whilst the procedure is fully automated, our tools also provide a light level of manual editing.

  2. Wavelets

    NASA Astrophysics Data System (ADS)

    DeVore, Ronald A.; Lucier, Bradley J.

    The subject of `wavelets' is expanding at such a tremendous rate that it is impossible to give, within these few pages, a complete introduction to all aspects of its theory. We hope, however, to allow the reader to become sufficiently acquainted with the subject to understand, in part, the enthusiasm of its proponents toward its potential application to various numerical problems. Furthermore, we hope that our exposition can guide the reader who wishes to make more serious excursions into the subject. Our viewpoint is biased by our experience in approximation theory and data compression; we warn the reader that there are other viewpoints that are either not represented here or discussed only briefly. For example, orthogonal wavelets were developed primarily in the context of signal processing, an application upon which we touch only indirectly. However, there are several good expositions (e.g. Daubechies (1990) and Rioul and Vetterli (1991)) of this application. A discussion of wavelet decompositions in the context of Littlewood-Paley theory can be found in the monograph of Frazier et al. (1991). We shall also not attempt to give a complete discussion of the history of wavelets. Historical accounts can be found in the book of Meyer (1990) and the introduction of the article of Daubechies (1990). We shall try to give sufficient historical commentary in the course of our presentation to provide some feeling for the subject's development.

  3. Collaboration on Scene Graph Based 3D Data

    NASA Astrophysics Data System (ADS)

    Ammon, Lorenz; Bieri, Hanspeter

    Professional 3D digital content creation tools, like Alias Maya or discreet 3ds max, offer only limited support for a team of artists to work on a 3D model collaboratively. We present a scene graph repository system that enables fine-grained collaboration on scenes built using standard 3D DCC tools by applying the concept of collaborative versions to a general attributed scene graph. Artists can work on the same scene in parallel without locking out each other. The artists' changes to a scene are regularly merged to ensure that all artists can see each others progress and collaborate on current data. We introduce the concept of indirect changes and indirect conflicts to systematically inspect the effects that collaborative changes have on a scene. Inspecting indirect conflicts helps maintaining scene consistency by systematically looking for inconsistencies at the right places.

  4. 3-dimensional (3D) fabricated polymer based drug delivery systems.

    PubMed

    Moulton, Simon E; Wallace, Gordon G

    2014-11-10

    Drug delivery from 3-dimensional (3D) structures is a rapidly growing area of research. It is essential to achieve structures wherein drug stability is ensured, the drug loading capacity is appropriate and the desired controlled release profile can be attained. Attention must also be paid to the development of appropriate fabrication machinery that allows 3D drug delivery systems (DDS) to be produced in a simple, reliable and reproducible manner. The range of fabrication methods currently being used to form 3D DDSs include electrospinning (solution and melt), wet-spinning and printing (3-dimensional). The use of these techniques enables production of DDSs from the macro-scale down to the nano-scale. This article reviews progress in these fabrication techniques to form DDSs that possess desirable drug delivery kinetics for a wide range of applications.

  5. Axisymmetric Implementation for 3D-Based DSMC Codes

    NASA Technical Reports Server (NTRS)

    Stewart, Benedicte; Lumpkin, F. E.; LeBeau, G. J.

    2011-01-01

    The primary objective in developing NASA s DSMC Analysis Code (DAC) was to provide a high fidelity modeling tool for 3D rarefied flows such as vacuum plume impingement and hypersonic re-entry flows [1]. The initial implementation has been expanded over time to offer other capabilities including a novel axisymmetric implementation. Because of the inherently 3D nature of DAC, this axisymmetric implementation uses a 3D Cartesian domain and 3D surfaces. Molecules are moved in all three dimensions but their movements are limited by physical walls to a small wedge centered on the plane of symmetry (Figure 1). Unfortunately, far from the axis of symmetry, the cell size in the direction perpendicular to the plane of symmetry (the Z-direction) may become large compared to the flow mean free path. This frequently results in inaccuracies in these regions of the domain. A new axisymmetric implementation is presented which aims to solve this issue by using Bird s approach for the molecular movement while preserving the 3D nature of the DAC software [2]. First, the computational domain is similar to that previously used such that a wedge must still be used to define the inflow surface and solid walls within the domain. As before molecules are created inside the inflow wedge triangles but they are now rotated back to the symmetry plane. During the move step, molecules are moved in 3D but instead of interacting with the wedge walls, the molecules are rotated back to the plane of symmetry at the end of the move step. This new implementation was tested for multiple flows over axisymmetric shapes, including a sphere, a cone, a double cone and a hollow cylinder. Comparisons to previous DSMC solutions and experiments, when available, are made.

  6. The EM Method in a Probabilistic Wavelet-Based MRI Denoising

    PubMed Central

    2015-01-01

    Human body heat emission and others external causes can interfere in magnetic resonance image acquisition and produce noise. In this kind of images, the noise, when no signal is present, is Rayleigh distributed and its wavelet coefficients can be approximately modeled by a Gaussian distribution. Noiseless magnetic resonance images can be modeled by a Laplacian distribution in the wavelet domain. This paper proposes a new magnetic resonance image denoising method to solve this fact. This method performs shrinkage of wavelet coefficients based on the conditioned probability of being noise or detail. The parameters involved in this filtering approach are calculated by means of the expectation maximization (EM) method, which avoids the need to use an estimator of noise variance. The efficiency of the proposed filter is studied and compared with other important filtering techniques, such as Nowak's, Donoho-Johnstone's, Awate-Whitaker's, and nonlocal means filters, in different 2D and 3D images. PMID:26089959

  7. The EM Method in a Probabilistic Wavelet-Based MRI Denoising.

    PubMed

    Martin-Fernandez, Marcos; Villullas, Sergio

    2015-01-01

    Human body heat emission and others external causes can interfere in magnetic resonance image acquisition and produce noise. In this kind of images, the noise, when no signal is present, is Rayleigh distributed and its wavelet coefficients can be approximately modeled by a Gaussian distribution. Noiseless magnetic resonance images can be modeled by a Laplacian distribution in the wavelet domain. This paper proposes a new magnetic resonance image denoising method to solve this fact. This method performs shrinkage of wavelet coefficients based on the conditioned probability of being noise or detail. The parameters involved in this filtering approach are calculated by means of the expectation maximization (EM) method, which avoids the need to use an estimator of noise variance. The efficiency of the proposed filter is studied and compared with other important filtering techniques, such as Nowak's, Donoho-Johnstone's, Awate-Whitaker's, and nonlocal means filters, in different 2D and 3D images.

  8. 3D Clumped Cell Segmentation Using Curvature Based Seeded Watershed

    PubMed Central

    Atta-Fosu, Thomas; Guo, Weihong; Jeter, Dana; Mizutani, Claudia M.; Stopczynski, Nathan; Sousa-Neves, Rui

    2017-01-01

    Image segmentation is an important process that separates objects from the background and also from each other. Applied to cells, the results can be used for cell counting which is very important in medical diagnosis and treatment, and biological research that is often used by scientists and medical practitioners. Segmenting 3D confocal microscopy images containing cells of different shapes and sizes is still challenging as the nuclei are closely packed. The watershed transform provides an efficient tool in segmenting such nuclei provided a reasonable set of markers can be found in the image. In the presence of low-contrast variation or excessive noise in the given image, the watershed transform leads to over-segmentation (a single object is overly split into multiple objects). The traditional watershed uses the local minima of the input image and will characteristically find multiple minima in one object unless they are specified (marker-controlled watershed). An alternative to using the local minima is by a supervised technique called seeded watershed, which supplies single seeds to replace the minima for the objects. Consequently, the accuracy of a seeded watershed algorithm relies on the accuracy of the predefined seeds. In this paper, we present a segmentation approach based on the geometric morphological properties of the ‘landscape’ using curvatures. The curvatures are computed as the eigenvalues of the Shape matrix, producing accurate seeds that also inherit the original shape of their respective cells. We compare with some popular approaches and show the advantage of the proposed method. PMID:28280723

  9. Microseismic network design assessment based on 3D ray tracing

    NASA Astrophysics Data System (ADS)

    Näsholm, Sven Peter; Wuestefeld, Andreas; Lubrano-Lavadera, Paul; Lang, Dominik; Kaschwich, Tina; Oye, Volker

    2016-04-01

    There is increasing demand on the versatility of microseismic monitoring networks. In early projects, being able to locate any triggers was considered a success. These early successes led to a better understanding of how to extract value from microseismic results. Today operators, regulators, and service providers work closely together in order to find the optimum network design to meet various requirements. In the current study we demonstrate an integrated and streamlined network capability assessment approach. It is intended for use during the microseismic network design process prior to installation. The assessments are derived from 3D ray tracing between a grid of event points and the sensors. Three aspects are discussed: 1) Magnitude of completeness or detection limit; 2) Event location accuracy; and 3) Ground-motion hazard. The network capability parameters 1) and 2) are estimated at all hypothetic event locations and are presented in the form of maps given a seismic sensor coordinate scenario. In addition, the ray tracing traveltimes permit to estimate the point-spread-functions (PSFs) at the event grid points. PSFs are useful in assessing the resolution and focusing capability of the network for stacking-based event location and imaging methods. We estimate the performance for a hypothetical network case with 11 sensors. We consider the well-documented region around the San Andreas Fault Observatory at Depth (SAFOD) located north of Parkfield, California. The ray tracing is done through a detailed velocity model which covers a 26.2 by 21.2 km wide area around the SAFOD drill site with a resolution of 200 m both for the P-and S-wave velocities. Systematic network capability assessment for different sensor site scenarios prior to installation facilitates finding a final design which meets the survey objectives.

  10. Wavelet based image visibility enhancement of IR images

    NASA Astrophysics Data System (ADS)

    Jiang, Qin; Owechko, Yuri; Blanton, Brendan

    2016-05-01

    Enhancing the visibility of infrared images obtained in a degraded visibility environment is very important for many applications such as surveillance, visual navigation in bad weather, and helicopter landing in brownout conditions. In this paper, we present an IR image visibility enhancement system based on adaptively modifying the wavelet coefficients of the images. In our proposed system, input images are first filtered by a histogram-based dynamic range filter in order to remove sensor noise and convert the input images into 8-bit dynamic range for efficient processing and display. By utilizing a wavelet transformation, we modify the image intensity distribution and enhance image edges simultaneously. In the wavelet domain, low frequency wavelet coefficients contain original image intensity distribution while high frequency wavelet coefficients contain edge information for the original images. To modify the image intensity distribution, an adaptive histogram equalization technique is applied to the low frequency wavelet coefficients while to enhance image edges, an adaptive edge enhancement technique is applied to the high frequency wavelet coefficients. An inverse wavelet transformation is applied to the modified wavelet coefficients to obtain intensity images with enhanced visibility. Finally, a Gaussian filter is used to remove blocking artifacts introduced by the adaptive techniques. Since wavelet transformation uses down-sampling to obtain low frequency wavelet coefficients, histogram equalization of low-frequency coefficients is computationally more efficient than histogram equalization of the original images. We tested the proposed system with degraded IR images obtained from a helicopter landing in brownout conditions. Our experimental results show that the proposed system is effective for enhancing the visibility of degraded IR images.

  11. Discrete directional wavelet bases for image compression

    NASA Astrophysics Data System (ADS)

    Dragotti, Pier L.; Velisavljevic, Vladan; Vetterli, Martin; Beferull-Lozano, Baltasar

    2003-06-01

    The application of the wavelet transform in image processing is most frequently based on a separable construction. Lines and columns in an image are treated independently and the basis functions are simply products of the corresponding one dimensional functions. Such method keeps simplicity in design and computation, but is not capable of capturing properly all the properties of an image. In this paper, a new truly separable discrete multi-directional transform is proposed with a subsampling method based on lattice theory. Alternatively, the subsampling can be omitted and this leads to a multi-directional frame. This transform can be applied in many areas like denoising, non-linear approximation and compression. The results on non-linear approximation and denoising show very interesting gains compared to the standard two-dimensional analysis.

  12. Content based image retrieval based on wavelet transform coefficients distribution.

    PubMed

    Lamard, Mathieu; Cazuguel, Guy; Quellec, Gwénolé; Bekri, Lynda; Roux, Christian; Cochener, Béatrice

    2007-01-01

    In this paper we propose a content based image retrieval method for diagnosis aid in medical fields. We characterize images without extracting significant features by using distribution of coefficients obtained by building signatures from the distribution of wavelet transform. The research is carried out by computing signature distances between the query and database images. Several signatures are proposed; they use a model of wavelet coefficient distribution. To enhance results, a weighted distance between signatures is used and an adapted wavelet base is proposed. Retrieval efficiency is given for different databases including a diabetic retinopathy, a mammography and a face database. Results are promising: the retrieval efficiency is higher than 95% for some cases using an optimization process.

  13. Face recognition based on matching of local features on 3D dynamic range sequences

    NASA Astrophysics Data System (ADS)

    Echeagaray-Patrón, B. A.; Kober, Vitaly

    2016-09-01

    3D face recognition has attracted attention in the last decade due to improvement of technology of 3D image acquisition and its wide range of applications such as access control, surveillance, human-computer interaction and biometric identification systems. Most research on 3D face recognition has focused on analysis of 3D still data. In this work, a new method for face recognition using dynamic 3D range sequences is proposed. Experimental results are presented and discussed using 3D sequences in the presence of pose variation. The performance of the proposed method is compared with that of conventional face recognition algorithms based on descriptors.

  14. Wavelet-based approach to character skeleton.

    PubMed

    You, Xinge; Tang, Yuan Yan

    2007-05-01

    Character skeleton plays a significant role in character recognition. The strokes of a character may consist of two regions, i.e., singular and regular regions. The intersections and junctions of the strokes belong to singular region, while the straight and smooth parts of the strokes are categorized to regular region. Therefore, a skeletonization method requires two different processes to treat the skeletons in theses two different regions. All traditional skeletonization algorithms are based on the symmetry analysis technique. The major problems of these methods are as follows. 1) The computation of the primary skeleton in the regular region is indirect, so that its implementation is sophisticated and costly. 2) The extracted skeleton cannot be exactly located on the central line of the stroke. 3) The captured skeleton in the singular region may be distorted by artifacts and branches. To overcome these problems, a novel scheme of extracting the skeleton of character based on wavelet transform is presented in this paper. This scheme consists of two main steps, namely: a) extraction of primary skeleton in the regular region and b) amendment processing of the primary skeletons and connection of them in the singular region. A direct technique is used in the first step, where a new wavelet-based symmetry analysis is developed for finding the central line of the stroke directly. A novel method called smooth interpolation is designed in the second step, where a smooth operation is applied to the primary skeleton, and, thereafter, the interpolation compensation technique is proposed to link the primary skeleton, so that the skeleton in the singular region can be produced. Experiments are conducted and positive results are achieved, which show that the proposed skeletonization scheme is applicable to not only binary image but also gray-level image, and the skeleton is robust against noise and affine transform.

  15. Wavelet-based Multiresolution Particle Methods

    NASA Astrophysics Data System (ADS)

    Bergdorf, Michael; Koumoutsakos, Petros

    2006-03-01

    Particle methods offer a robust numerical tool for solving transport problems across disciplines, such as fluid dynamics, quantitative biology or computer graphics. Their strength lies in their stability, as they do not discretize the convection operator, and appealing numerical properties, such as small dissipation and dispersion errors. Many problems of interest are inherently multiscale, and their efficient solution requires either multiscale modeling approaches or spatially adaptive numerical schemes. We present a hybrid particle method that employs a multiresolution analysis to identify and adapt to small scales in the solution. The method combines the versatility and efficiency of grid-based Wavelet collocation methods while retaining the numerical properties and stability of particle methods. The accuracy and efficiency of this method is then assessed for transport and interface capturing problems in two and three dimensions, illustrating the capabilities and limitations of our approach.

  16. OB3D, a new set of 3D objects available for research: a web-based study

    PubMed Central

    Buffat, Stéphane; Chastres, Véronique; Bichot, Alain; Rider, Delphine; Benmussa, Frédéric; Lorenceau, Jean

    2014-01-01

    Studying object recognition is central to fundamental and clinical research on cognitive functions but suffers from the limitations of the available sets that cannot always be modified and adapted to meet the specific goals of each study. We here present a new set of 3D scans of real objects available on-line as ASCII files, OB3D. These files are lists of dots, each defined by a triplet of spatial coordinates and their normal that allow simple and highly versatile transformations and adaptations. We performed a web-based experiment to evaluate the minimal number of dots required for the denomination and categorization of these objects, thus providing a reference threshold. We further analyze several other variables derived from this data set, such as the correlations with object complexity. This new stimulus set, which was found to activate the Lower Occipital Complex (LOC) in another study, may be of interest for studies of cognitive functions in healthy participants and patients with cognitive impairments, including visual perception, language, memory, etc. PMID:25339920

  17. Silk-based anisotropical 3D biotextiles for bone regeneration.

    PubMed

    Ribeiro, Viviana P; Silva-Correia, Joana; Nascimento, Ana I; da Silva Morais, Alain; Marques, Alexandra P; Ribeiro, Ana S; Silva, Carla J; Bonifácio, Graça; Sousa, Rui A; Oliveira, Joaquim M; Oliveira, Ana L; Reis, Rui L

    2017-04-01

    Bone loss in the craniofacial complex can been treated using several conventional therapeutic strategies that face many obstacles and limitations. In this work, novel three-dimensional (3D) biotextile architectures were developed as a possible strategy for flat bone regeneration applications. As a fully automated processing route, this strategy as potential to be easily industrialized. Silk fibroin (SF) yarns were processed into weft-knitted fabrics spaced by a monofilament of polyethylene terephthalate (PET). A comparative study with a similar 3D structure made entirely of PET was established. Highly porous scaffolds with homogeneous pore distribution were observed using micro-computed tomography analysis. The wet state dynamic mechanical analysis revealed a storage modulus In the frequency range tested, the storage modulus values obtained for SF-PET scaffolds were higher than for the PET scaffolds. Human adipose-derived stem cells (hASCs) cultured on the SF-PET spacer structures showed the typical pattern for ALP activity under osteogenic culture conditions. Osteogenic differentiation of hASCs on SF-PET and PET constructs was also observed by extracellular matrix mineralization and expression of osteogenic-related markers (osteocalcin, osteopontin and collagen type I) after 28 days of osteogenic culture, in comparison to the control basal medium. The quantification of convergent macroscopic blood vessels toward the scaffolds by a chick chorioallantoic membrane assay, showed higher angiogenic response induced by the SF-PET textile scaffolds than PET structures and gelatin sponge controls. Subcutaneous implantation in CD-1 mice revealed tissue ingrowth's accompanied by blood vessels infiltration in both spacer constructs. The structural adaptability of textile structures combined to the structural similarities of the 3D knitted spacer fabrics to craniofacial bone tissue and achieved biological performance, make these scaffolds a possible solution for tissue

  18. Image coding based on energy-sorted wavelet packets

    NASA Astrophysics Data System (ADS)

    Kong, Lin-Wen; Lay, Kuen-Tsair

    1995-04-01

    The discrete wavelet transform performs multiresolution analysis, which effectively decomposes a digital image into components with different degrees of details. In practice, it is usually implemented in the form of filter banks. If the filter banks are cascaded and both the low-pass and the high-pass components are further decomposed, a wavelet packet is obtained. The coefficients of the wavelet packet effectively represent subimages in different resolution levels. In the energy-sorted wavelet- packet decomposition, all subimages in the packet are then sorted according to their energies. The most important subimages, as measured by the energy, are preserved and coded. By investigating the histogram of each subimage, it is found that the pixel values are well modelled by the Laplacian distribution. Therefore, the Laplacian quantization is applied to quantized the subimages. Experimental results show that the image coding scheme based on wavelet packets achieves high compression ratio while preserving satisfactory image quality.

  19. Remote sensing image compression method based on lift scheme wavelet transform

    NASA Astrophysics Data System (ADS)

    Tao, Hongjiu; Tang, Xinjian; Liu, Jian; Tian, Jinwen

    2003-06-01

    Based on lifting scheme and the construction theorem of the integer Haar wavelet and biorthogonal wavelet, we propose a new integer wavelet transform construct method on the basis of lift scheme after introduciton of constructing specific-demand biorthogonal wavelet transform using Harr wavelet and Lazy wavelet. In this paper, we represent the method and algorithm of the lifting scheme, and we also give mathematical formulation on this method and experimental results as well.

  20. Handheld underwater 3D sensor based on fringe projection technique

    NASA Astrophysics Data System (ADS)

    Bräuer-Burchardt, Christian; Heinze, Matthias; Schmidt, Ingo; Meng, Lichun; Ramm, Roland; Kühmstedt, Peter; Notni, Gunther

    2015-05-01

    A new, handheld 3D surface scanner was developed especially for underwater use until a diving depth of about 40 meters. Additionally, the sensor is suitable for the outdoor use under bad weather circumstance like splashing water, wind, and bad illumination conditions. The optical components of the sensor are two cameras and one projector. The measurement field is about 250 mm x 200 mm. The depth resolution is about 50 μm and the lateral resolution is approximately 150 μm. The weight of the scanner is about 10 kg. The housing was produced of synthetic powder using a 3D printing technique. The measurement time for one scan is between a third and a half second. The computer for measurement control and data analysis is already integrated into the housing of the scanner. A display on the backside presents the results of each measurement graphically for a real-time evaluation of the user during the recording of the measurement data.

  1. Wavelet-based detection of clods on a soil surface

    NASA Astrophysics Data System (ADS)

    Vannier, E.; Ciarletti, V.; Darboux, F.

    2009-11-01

    One of the aims of the tillage operation is to produce a specific range of clod sizes, suitable for plant emergence. Due to its cloddy structure, a tilled soil surface has its own roughness, which is connected also with soil water content and erosion phenomena. The comprehension and modeling of surface runoff and erosion require that the micro-topography of the soil surface is well estimated. Therefore, the present paper focuses on the soil surface analysis and characterization. An original method consisting in detecting the individual clods or large aggregates on a 3D digital elevation model (DEM) of the soil surface is introduced. A multiresolution decomposition of the surface is performed by wavelet transform. Then a supervised local maxima extraction is performed on the different sub surfaces and a last process makes the validation of the extractions and the merging of the different scales. The method of detection was evaluated with the help of a soil scientist on a controlled surface made in the laboratory as well as on real seedbed and ploughed surfaces, made by tillage operations in an agricultural field. The identifications of the clods are in good agreement, with an overall sensitivity of 84% and a specificity of 94%. The false positive or false negative detections may have several causes. Some very nearby clods may have been smoothed together in the approximation process. Other clods may be embedded into another peace of the surface relief such as another bigger clod or a part of the furrow. At last, the low levels of decomposition are dependent on the resolution and the measurement noise of the DEM. Therefore, some borders of clods may be difficult to determine. The wavelet-based detection method seems to be suitable for soil surfaces described by 2 or 3 levels of approximation such as seedbeds.

  2. Study on fluorometric discrimination of phytoplankton based on time-series vectors of wavelet transform.

    PubMed

    Zhang, Fang; Su, Rongguo; He, Jianfeng; Cai, Minghong; Luo, Wei; Wang, Xiulin

    2010-02-01

    The feasibility of using time domain of wavelet transform as characteristics to establish a fluorometric discrimination method of phytoplankton was discussed. Twelve phytoplankton species belonging to nine genera of five divisions were studied. Five steps were introduced: firstly, the feasibility of utilizing 3D fluorescence spectra (3D-FS) to discriminate phytoplankton was discussed; the relative standard deviation (RSD) and included angle cosine (IAC) were used as the test criterion. 3D-FS had such potentials, for most RSD were <5% and most IAC were >0.990. Secondly, the 3D-FS were decomposed by db7 wavelet and time-series vectors (TSVs) were generated. Thirdly, the optimal characteristic spectra (OCS) were selected from the TSV by Bayesian linear discriminant analysis (BLDA). The ability of OCS to classify phytoplankton was tested, and the correct classification ratios (CCRs) at different levels were obtained. Most CCRs were 90-100% at the species level. They were >98% at the genus level, and >99% at the division level. Fourthly, the growth and light stability of the OCS were tested. Both stabilities were high with lower RSD (<3%) and higher IAC (>0.999) compared with 3D-FS. Fifthly, a "database of reference spectra" consisting of 46 reference spectra was established by hierarchical cluster analysis (HCA). Based on this, the discrimination method of phytoplankton species was established by nonnegative least squares (NNLSs). Most reference spectra were representative to phytoplankton species; and had moderate anti-noise ability: With noise 98% at the genus level and >99% at the division level. 20% noise was a larger interference which made CDRs down to 85% at the genus level and to 99% at the division level. A fluorometric discrimination method of phytoplankton could be established based on TSV of wavelet transform.

  3. Coniferous Canopy BRF Simulation Based on 3-D Realistic Scene

    NASA Technical Reports Server (NTRS)

    Wang, Xin-yun; Guo, Zhi-feng; Qin, Wen-han; Sun, Guo-qing

    2011-01-01

    It is difficulties for the computer simulation method to study radiation regime at large-scale. Simplified coniferous model was investigate d in the present study. It makes the computer simulation methods such as L-systems and radiosity-graphics combined method (RGM) more powerf ul in remote sensing of heterogeneous coniferous forests over a large -scale region. L-systems is applied to render 3-D coniferous forest scenarios: and RGM model was used to calculate BRF (bidirectional refle ctance factor) in visible and near-infrared regions. Results in this study show that in most cases both agreed well. Meanwhiie at a tree and forest level. the results are also good.

  4. 3D fingerprint imaging system based on full-field fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Huang, Shujun; Zhang, Zonghua; Zhao, Yan; Dai, Jie; Chen, Chao; Xu, Yongjia; Zhang, E.; Xie, Lili

    2014-01-01

    As an unique, unchangeable and easily acquired biometrics, fingerprint has been widely studied in academics and applied in many fields over the years. The traditional fingerprint recognition methods are based on the obtained 2D feature of fingerprint. However, fingerprint is a 3D biological characteristic. The mapping from 3D to 2D loses 1D information and causes nonlinear distortion of the captured fingerprint. Therefore, it is becoming more and more important to obtain 3D fingerprint information for recognition. In this paper, a novel 3D fingerprint imaging system is presented based on fringe projection technique to obtain 3D features and the corresponding color texture information. A series of color sinusoidal fringe patterns with optimum three-fringe numbers are projected onto a finger surface. From another viewpoint, the fringe patterns are deformed by the finger surface and captured by a CCD camera. 3D shape data of the finger can be obtained from the captured fringe pattern images. This paper studies the prototype of the 3D fingerprint imaging system, including principle of 3D fingerprint acquisition, hardware design of the 3D imaging system, 3D calibration of the system, and software development. Some experiments are carried out by acquiring several 3D fingerprint data. The experimental results demonstrate the feasibility of the proposed 3D fingerprint imaging system.

  5. 3-D Adaptive Sparsity Based Image Compression with Applications to Optical Coherence Tomography

    PubMed Central

    Fang, Leyuan; Li, Shutao; Kang, Xudong; Izatt, Joseph A.; Farsiu, Sina

    2015-01-01

    We present a novel general-purpose compression method for tomographic images, termed 3D adaptive sparse representation based compression (3D-ASRC). In this paper, we focus on applications of 3D-ASRC for the compression of ophthalmic 3D optical coherence tomography (OCT) images. The 3D-ASRC algorithm exploits correlations among adjacent OCT images to improve compression performance, yet is sensitive to preserving their differences. Due to the inherent denoising mechanism of the sparsity based 3D-ASRC, the quality of the compressed images are often better than the raw images they are based on. Experiments on clinical-grade retinal OCT images demonstrate the superiority of the proposed 3D-ASRC over other well-known compression methods. PMID:25561591

  6. Detection of Impedance Cardioaraphy's Characteristic Points Based on Wavelet Transform.

    PubMed

    Shuguang, Zhao; Yanhong, Fang; Hailong, Zhao; Min, Tang

    2005-01-01

    With observation that singularities of a multi-scale wavelet transform result are related to discontinuities of the signal, a novel wavelet transform based method is proposed in this paper for detection of biomedical signals' characteristic points. For impedance cardiography signals, characteristic points of the signal dz/dt, including its peaks, start-point and end-point of ventricular ejection are detected and located by using singularities of wavelet transform (e.g., crossover points, maxima, minima). Experiment results showed validity of the approach.

  7. 2D Log-Gabor Wavelet Based Action Recognition

    NASA Astrophysics Data System (ADS)

    Li, Ning; Xu, De

    The frequency response of log-Gabor function matches well the frequency response of primate visual neurons. In this letter, motion-salient regions are extracted based on the 2D log-Gabor wavelet transform of the spatio-temporal form of actions. A supervised classification technique is then used to classify the actions. The proposed method is robust to the irregular segmentation of actors. Moreover, the 2D log-Gabor wavelet permits more compact representation of actions than the recent neurobiological models using Gabor wavelet.

  8. Hybrid atlas-based and image-based approach for segmenting 3D brain MRIs

    NASA Astrophysics Data System (ADS)

    Bueno, Gloria; Musse, Olivier; Heitz, Fabrice; Armspach, Jean-Paul

    2001-07-01

    This work is a contribution to the problem of localizing key cerebral structures in 3D MRIs and its quantitative evaluation. In pursuing it, the cooperation between an image-based segmentation method and a hierarchical deformable registration approach has been considered. The segmentation relies on two main processes: homotopy modification and contour decision. The first one is achieved by a marker extraction stage where homogeneous 3D regions of an image, I(s), from the data set are identified. These regions, M(I), are obtained combining information from deformable atlas, achieved by the warping of eight previous labeled maps on I(s). Then, the goal of the decision stage is to precisely locate the contours of the 3D regions set by the markers. This contour decision is performed by a 3D extension of the watershed transform. The anatomical structures taken into consideration and embedded into the atlas are brain, ventricles, corpus callosum, cerebellum, right and left hippocampus, medulla and midbrain. The hybrid method operates fully automatically and in 3D, successfully providing segmented brain structures. The quality of the segmentation has been studied in terms of the detected volume ratio by using kappa statistic and ROC analysis. Results of the method are shown and validated on a 3D MRI phantom. This study forms part of an on-going long term research aiming at the creation of a 3D probabilistic multi-purpose anatomical brain atlas.

  9. New 3-D microarray platform based on macroporous polymer monoliths.

    PubMed

    Rober, M; Walter, J; Vlakh, E; Stahl, F; Kasper, C; Tennikova, T

    2009-06-30

    Polymer macroporous monoliths are widely used as efficient sorbents in different, mostly dynamic, interphase processes. In this paper, monolithic materials strongly bound to the inert glass surface are suggested as operative matrices at the development of three-dimensional (3-D) microarrays. For this purpose, several rigid macroporous copolymers differed by reactivity and hydrophobic-hydrophilic properties were synthesized and tested: (1) glycidyl methacrylate-co-ethylene dimethacrylate (poly(GMA-co-EDMA)), (2) glycidyl methacrylate-co-glycerol dimethacrylate (poly(GMA-co-GDMA)), (3) N-hydroxyphthalimide ester of acrylic acid-co-glycidyl methacrylate-co-ethylene dimethacrylate (poly(HPIEAA-co-GMA-co-EDMA)), (4) 2-cyanoethyl methacrylate-co-ethylene dimethacrylate (poly(CEMA-co-EDMA)), and (5) 2-cyanoethyl methacrylate-co-2-hydroxyethyl methacrylate-co-ethylene dimethacrylate (poly(CEMA-co-HEMA-co-EDMA)). The constructed devices were used as platforms for protein microarrays construction and model mouse IgG-goat anti-mouse IgG affinity pair was used to demonstrate the potential of developed test-systems, as well as to optimize microanalytical conditions. The offered microarray platforms were applied to detect the bone tissue marker osteopontin directly in cell culture medium.

  10. Contactless operating table control based on 3D image processing.

    PubMed

    Schröder, Stephan; Loftfield, Nina; Langmann, Benjamin; Frank, Klaus; Reithmeier, Eduard

    2014-01-01

    Interaction with mobile consumer devices leads to a higher acceptance and affinity of persons to natural user interfaces and perceptional interaction possibilities. New interaction modalities become accessible and are capable to improve human machine interaction even in complex and high risk environments, like the operation room. Here, manifold medical disciplines cause a great variety of procedures and thus staff and equipment. One universal challenge is to meet the sterility requirements, for which common contact-afflicted remote interfaces always pose a potential risk causing a hazard for the process. The proposed operating table control system overcomes this process risk and thus improves the system usability significantly. The 3D sensor system, the Microsoft Kinect, captures the motion of the user, allowing a touchless manipulation of an operating table. Three gestures enable the user to select, activate and manipulate all segments of the motorised system in a safe and intuitive way. The gesture dynamics are synchronised with the table movement. In a usability study, 15 participants evaluated the system with a system usability score by Broke of 79. This states a high potential for implementation and acceptance in interventional environments. In the near future, even processes with higher risks could be controlled with the proposed interface, while interfaces become safer and more direct.

  11. MIMO based 3D imaging system at 360 GHz

    NASA Astrophysics Data System (ADS)

    Herschel, R.; Nowok, S.; Zimmermann, R.; Lang, S. A.; Pohl, N.

    2016-05-01

    A MIMO radar imaging system at 360 GHz is presented as a part of the comprehensive approach of the European FP7 project TeraSCREEN, using multiple frequency bands for active and passive imaging. The MIMO system consists of 16 transmitter and 16 receiver antennas within one single array. Using a bandwidth of 30 GHz, a range resolution up to 5 mm is obtained. With the 16×16 MIMO system 256 different azimuth bins can be distinguished. Mechanical beam steering is used to measure 130 different elevation angles where the angular resolution is obtained by a focusing elliptical mirror. With this system a high resolution 3D image can be generated with 4 frames per second, each containing 16 million points. The principle of the system is presented starting from the functional structure, covering the hardware design and including the digital image generation. This is supported by simulated data and discussed using experimental results from a preliminary 90 GHz system underlining the feasibility of the approach.

  12. Research of Fast 3D Imaging Based on Multiple Mode

    NASA Astrophysics Data System (ADS)

    Chen, Shibing; Yan, Huimin; Ni, Xuxiang; Zhang, Xiuda; Wang, Yu

    2016-02-01

    Three-dimensional (3D) imaging has received increasingly extensive attention and has been widely used currently. Lots of efforts have been put on three-dimensional imaging method and system study, in order to meet fast and high accurate requirement. In this article, we realize a fast and high quality stereo matching algorithm on field programmable gate array (FPGA) using the combination of time-of-flight (TOF) camera and binocular camera. Images captured from the two cameras own a same spatial resolution, letting us use the depth maps taken by the TOF camera to figure initial disparity. Under the constraint of the depth map as the stereo pairs when comes to stereo matching, expected disparity of each pixel is limited within a narrow search range. In the meanwhile, using field programmable gate array (FPGA, altera cyclone IV series) concurrent computing we can configure multi core image matching system, thus doing stereo matching on embedded system. The simulation results demonstrate that it can speed up the process of stereo matching and increase matching reliability and stability, realize embedded calculation, expand application range.

  13. Image denoising based on wavelet cone of influence analysis

    NASA Astrophysics Data System (ADS)

    Pang, Wei; Li, Yufeng

    2009-11-01

    Donoho et al have proposed a method for denoising by thresholding based on wavelet transform, and indeed, the application of their method to image denoising has been extremely successful. But this method is based on the assumption that the type of noise is only additive Gaussian white noise, which is not efficient to impulse noise. In this paper, a new image denoising algorithm based on wavelet cone of influence (COI) analyzing is proposed, and which can effectively remove the impulse noise and preserve the image edges via undecimated discrete wavelet transform (UDWT). Furthermore, combining with the traditional wavelet thresholding denoising method, it can be also used to restrain more widely type of noise such as Gaussian noise, impulse noise, poisson noise and other mixed noise. Experiment results illustrate the advantages of this method.

  14. An Automated Parallel Image Registration Technique Based on the Correlation of Wavelet Features

    NASA Technical Reports Server (NTRS)

    LeMoigne, Jacqueline; Campbell, William J.; Cromp, Robert F.; Zukor, Dorothy (Technical Monitor)

    2001-01-01

    With the increasing importance of multiple platform/multiple remote sensing missions, fast and automatic integration of digital data from disparate sources has become critical to the success of these endeavors. Our work utilizes maxima of wavelet coefficients to form the basic features of a correlation-based automatic registration algorithm. Our wavelet-based registration algorithm is tested successfully with data from the National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) and the Landsat/Thematic Mapper(TM), which differ by translation and/or rotation. By the choice of high-frequency wavelet features, this method is similar to an edge-based correlation method, but by exploiting the multi-resolution nature of a wavelet decomposition, our method achieves higher computational speeds for comparable accuracies. This algorithm has been implemented on a Single Instruction Multiple Data (SIMD) massively parallel computer, the MasPar MP-2, as well as on the CrayT3D, the Cray T3E and a Beowulf cluster of Pentium workstations.

  15. An Improved Spectral Background Subtraction Method Based on Wavelet Energy.

    PubMed

    Zhao, Fengkui; Wang, Jian; Wang, Aimin

    2016-12-01

    Most spectral background subtraction methods rely on the difference in frequency response of background compared with characteristic peaks. It is difficult to extract accurately the background components from the spectrum when characteristic peaks and background have overlaps in frequency domain. An improved background estimation algorithm based on iterative wavelet transform (IWT) is presented. The wavelet entropy principle is used to select the best wavelet basis. A criterion based on wavelet energy theory to determine the optimal iteration times is proposed. The case of energy dispersive X-ray spectroscopy is discussed for illustration. A simulated spectrum with a prior known background and an experimental spectrum are tested. The processing results of the simulated spectrum is compared with non-IWT and it demonstrates the superiority of the IWT. It has great significance to improve the accuracy for spectral analysis.

  16. Vision-Based 3D Motion Estimation for On-Orbit Proximity Satellite Tracking and Navigation

    DTIC Science & Technology

    2015-06-01

    printed using the Fortus 400mc 3D rapid- prototyping printer of the NPS Space Systems Academic Group, while the internal structure is made of aluminum...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited VISION-BASED 3D ...REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE VISION-BASED 3D MOTION ESTIMATION FOR ON-ORBIT PROXIMITY SATELLITE TRACKING

  17. 3D-2D ultrasound feature-based registration for navigated prostate biopsy: a feasibility study.

    PubMed

    Selmi, Sonia Y; Promayon, Emmanuel; Troccaz, Jocelyne

    2016-08-01

    The aim of this paper is to describe a 3D-2D ultrasound feature-based registration method for navigated prostate biopsy and its first results obtained on patient data. A system combining a low-cost tracking system and a 3D-2D registration algorithm was designed. The proposed 3D-2D registration method combines geometric and image-based distances. After extracting features from ultrasound images, 3D and 2D features within a defined distance are matched using an intensity-based function. The results are encouraging and show acceptable errors with simulated transforms applied on ultrasound volumes from real patients.

  18. Classification of Underwater Signals Using Wavelet-Based Decompositions

    DTIC Science & Technology

    1998-06-01

    proposed by Learned and Willsky [21], uses the SVD information obtained from the power mapping, the second one selects the most within-a-class...34 SPIE, Vol. 2242, pp. 792-802, Wavelet Applications, 1994 [14] R. Coifman and D. Donoho, "Translation-Invariant Denoising ," Internal Report...J. Barsanti, Jr., Denoising of Ocean Acoustic Signals Using Wavelet-Based Techniques, MSEE Thesis, Naval Postgraduate School, Monterey, California

  19. Disparity pattern-based autostereoscopic 3D metrology system for in situ measurement of microstructured surfaces.

    PubMed

    Li, Da; Cheung, Chi Fai; Ren, MingJun; Whitehouse, David; Zhao, Xing

    2015-11-15

    This paper presents a disparity pattern-based autostereoscopic (DPA) 3D metrology system that makes use of a microlens array to capture raw 3D information of the measured surface in a single snapshot through a CCD camera. Hence, a 3D digital model of the target surface with the measuring data is generated through a system-associated direct extraction of disparity information (DEDI) method. The DEDI method is highly efficient for performing the direct 3D mapping of the target surface based on tomography-like operation upon every depth plane with the defocused information excluded. Precise measurement results are provided through an error-elimination process based on statistical analysis. Experimental results show that the proposed DPA 3D metrology system is capable of measuring 3D microstructured surfaces with submicrometer measuring repeatability for high precision and in situ measurement of microstructured surfaces.

  20. Simultaneous spectrophotometric determination of Cd2+, Cu2+, and Zn2+ in rice and vegetal samples with dimethyl-spiro[isobenzofurane-1,6'-pyrorolo[2,3-d]pyrimidine]-2',3,4,5'(1'H,3'H,7'H)tetraone using wavelet transformation-feed forward neural networks.

    PubMed

    Tarighat, Maryam Abbasi; Mohammadizadeh, Mohammad Reza; Abdi, Gholamreza

    2013-07-17

    A multicomponent analysis method for the simultaneous spectrophotometric determination of the Cd(2+), Cu(2+), and Zn(2+) based on complex formation with dimethyl-spiro[isobenzofurane-1,6'-pyrorolo[2,3-d]pyrimidine]-2',3,4,5'(1'H,3'H,7'H)tetraone using wavelet transformation-feed forward neural network is proposed. The analytical data showed that metal to ligand ratios in all metal complexes was 1:1. The absorption spectra were evaluated with respect to synthetic ligand concentration and pH. It was found that, at pH 6.7, the complexation reactions were completed. Spectral data were reduced using continuous wavelet transformation (CWT) and subjected to artificial neural networks. The presence of nonlinearities was confirmed by a partial response plot. The structures of the CWT-feed forward neural networks (WT-FFNN) were simplified using the corresponding wavelet coefficients of mother wavelets. Once the optimal wavelet coefficients are selected, different ANN models can be employed for the calculation of the final calibration model. The proposed methods were successfully applied to the simultaneous determination of Cd(2+), Cu(2+), and Zn(2+) in rice, dill, tomato, and lettuce samples.

  1. A primitive-based 3D object recognition system

    NASA Technical Reports Server (NTRS)

    Dhawan, Atam P.

    1988-01-01

    An intermediate-level knowledge-based system for decomposing segmented data into three-dimensional primitives was developed to create an approximate three-dimensional description of the real world scene from a single two-dimensional perspective view. A knowledge-based approach was also developed for high-level primitive-based matching of three-dimensional objects. Both the intermediate-level decomposition and the high-level interpretation are based on the structural and relational matching; moreover, they are implemented in a frame-based environment.

  2. Wavelet-based target detection using multiscale directional analysis

    NASA Astrophysics Data System (ADS)

    Chambers, Bradley J.; Reynolds, William D., Jr.; Campbell, Derrick S.; Fennell, Darius K.; Ansari, Rashid

    2007-04-01

    Efficient processing of imagery derived from remote sensing systems has become ever more important due to increasing data sizes, rates, and bit depths. This paper proposes a target detection method that uses a special class of wavelets based on highly frequency-selective directional filter banks. The approach helps isolate object features in different directional filter output components. These components lend themselves well to the application of powerful denoising and edge detection procedures in the wavelet domain. Edge information is derived from directional wavelet decompositions to detect targets of known dimension in electro optical imagery. Results of successful detection of objects using the proposed method are presented in the paper. The approach highlights many of the benefits of working with directional wavelet analysis for image denoising and detection.

  3. Wavelet based characterization of ex vivo vertebral trabecular bone structure with 3T MRI compared to microCT

    SciTech Connect

    Krug, R; Carballido-Gamio, J; Burghardt, A; Haase, S; Sedat, J W; Moss, W C; Majumdar, S

    2005-04-11

    Trabecular bone structure and bone density contribute to the strength of bone and are important in the study of osteoporosis. Wavelets are a powerful tool to characterize and quantify texture in an image. In this study the thickness of trabecular bone was analyzed in 8 cylindrical cores of the vertebral spine. Images were obtained from 3 Tesla (T) magnetic resonance imaging (MRI) and micro-computed tomography ({micro}CT). Results from the wavelet based analysis of trabecular bone were compared with standard two-dimensional structural parameters (analogous to bone histomorphometry) obtained using mean intercept length (MR images) and direct 3D distance transformation methods ({micro}CT images). Additionally, the bone volume fraction was determined from MR images. We conclude that the wavelet based analyses delivers comparable results to the established MR histomorphometric measurements. The average deviation in trabecular thickness was less than one pixel size between the wavelet and the standard approach for both MR and {micro}CT analysis. Since the wavelet based method is less sensitive to image noise, we see an advantage of wavelet analysis of trabecular bone for MR imaging when going to higher resolution.

  4. Optimizing visual comfort for stereoscopic 3D display based on color-plus-depth signals.

    PubMed

    Shao, Feng; Jiang, Qiuping; Fu, Randi; Yu, Mei; Jiang, Gangyi

    2016-05-30

    Visual comfort is a long-facing problem in stereoscopic 3D (S3D) display. In this paper, targeting to produce S3D content based on color-plus-depth signals, a general framework for depth mapping to optimize visual comfort for S3D display is proposed. The main motivation of this work is to remap the depth range of color-plus-depth signals to a new depth range that is suitable to comfortable S3D display. Towards this end, we first remap the depth range globally based on the adjusted zero disparity plane, and then present a two-stage global and local depth optimization solution to solve the visual comfort problem. The remapped depth map is used to generate the S3D output. We demonstrate the power of our approach on perceptually uncomfortable and comfortable stereoscopic images.

  5. [3-D endocardial surface modelling based on the convex hull algorithm].

    PubMed

    Lu, Ying; Xi, Ri-hui; Shen, Hai-dong; Ye, You-li; Zhang, Yong

    2006-11-01

    In this paper, a method based on the convex hull algorithm is presented for extracting modelling data from the locations of catheter electrodes within a cardiac chamber, so as to create a 3-D model of the heart chamber during diastole and to obtain a good result in the 3-D reconstruction of the chamber based on VTK.

  6. A Tetraperylene Diimides Based 3D Nonfullerene Acceptor for Efficient Organic Photovoltaics.

    PubMed

    Liu, Shi-Yong; Wu, Chen-Hao; Li, Chang-Zhi; Liu, Sheng-Qiang; Wei, Kung-Hwa; Chen, Hong-Zheng; Jen, Alex K-Y

    2015-04-01

    A nonfullerene acceptor based on a 3D tetraperylene diimide is developed for bulk heterojunction organic photovoltaics. The disruption of perylene diimide planarity with a 3D framework suppresses the self-aggregation of perylene diimide and inhibits excimer formation. From planar monoperylene diimide to 3D tetraperylene diimide, a significant improvement of power conversion efficiency from 0.63% to 3.54% can be achieved.

  7. Wavelet-based compression of pathological images for telemedicine applications

    NASA Astrophysics Data System (ADS)

    Chen, Chang W.; Jiang, Jianfei; Zheng, Zhiyong; Wu, Xue G.; Yu, Lun

    2000-05-01

    In this paper, we present the performance evaluation of wavelet-based coding techniques as applied to the compression of pathological images for application in an Internet-based telemedicine system. We first study how well suited the wavelet-based coding is as it applies to the compression of pathological images, since these images often contain fine textures that are often critical to the diagnosis of potential diseases. We compare the wavelet-based compression with the DCT-based JPEG compression in the DICOM standard for medical imaging applications. Both objective and subjective measures have been studied in the evaluation of compression performance. These studies are performed in close collaboration with expert pathologists who have conducted the evaluation of the compressed pathological images and communication engineers and information scientists who designed the proposed telemedicine system. These performance evaluations have shown that the wavelet-based coding is suitable for the compression of various pathological images and can be integrated well with the Internet-based telemedicine systems. A prototype of the proposed telemedicine system has been developed in which the wavelet-based coding is adopted for the compression to achieve bandwidth efficient transmission and therefore speed up the communications between the remote terminal and the central server of the telemedicine system.

  8. Geofencing-Based Localization for 3d Data Acquisition Navigation

    NASA Astrophysics Data System (ADS)

    Nakagawa, M.; Kamio, T.; Yasojima, H.; Kobayashi, T.

    2016-06-01

    Users require navigation for many location-based applications using moving sensors, such as autonomous robot control, mapping route navigation and mobile infrastructure inspection. In indoor environments, indoor positioning systems using GNSSs can provide seamless indoor-outdoor positioning and navigation services. However, instabilities in sensor position data acquisition remain, because the indoor environment is more complex than the outdoor environment. On the other hand, simultaneous localization and mapping processing is better than indoor positioning for measurement accuracy and sensor cost. However, it is not easy to estimate position data from a single viewpoint directly. Based on these technical issues, we focus on geofencing techniques to improve position data acquisition. In this research, we propose a methodology to estimate more stable position or location data using unstable position data based on geofencing in indoor environments. We verify our methodology through experiments in indoor environments.

  9. A cross-platform solution for light field based 3D telemedicine.

    PubMed

    Wang, Gengkun; Xiang, Wei; Pickering, Mark

    2016-03-01

    Current telehealth services are dominated by conventional 2D video conferencing systems, which are limited in their capabilities in providing a satisfactory communication experience due to the lack of realism. The "immersiveness" provided by 3D technologies has the potential to promote telehealth services to a wider range of applications. However, conventional stereoscopic 3D technologies are deficient in many aspects, including low resolution and the requirement for complicated multi-camera setup and calibration, and special glasses. The advent of light field (LF) photography enables us to record light rays in a single shot and provide glasses-free 3D display with continuous motion parallax in a wide viewing zone, which is ideally suited for 3D telehealth applications. As far as our literature review suggests, there have been no reports of 3D telemedicine systems using LF technology. In this paper, we propose a cross-platform solution for a LF-based 3D telemedicine system. Firstly, a novel system architecture based on LF technology is established, which is able to capture the LF of a patient, and provide an immersive 3D display at the doctor site. For 3D modeling, we further propose an algorithm which is able to convert the captured LF to a 3D model with a high level of detail. For the software implementation on different platforms (i.e., desktop, web-based and mobile phone platforms), a cross-platform solution is proposed. Demo applications have been developed for 2D/3D video conferencing, 3D model display and edit, blood pressure and heart rate monitoring, and patient data viewing functions. The demo software can be extended to multi-discipline telehealth applications, such as tele-dentistry, tele-wound and tele-psychiatry. The proposed 3D telemedicine solution has the potential to revolutionize next-generation telemedicine technologies by providing a high quality immersive tele-consultation experience.

  10. A new approach towards image based virtual 3D city modeling by using close range photogrammetry

    NASA Astrophysics Data System (ADS)

    Singh, S. P.; Jain, K.; Mandla, V. R.

    2014-05-01

    3D city model is a digital representation of the Earth's surface and it's related objects such as building, tree, vegetation, and some manmade feature belonging to urban area. The demand of 3D city modeling is increasing day to day for various engineering and non-engineering applications. Generally three main image based approaches are using for virtual 3D city models generation. In first approach, researchers used Sketch based modeling, second method is Procedural grammar based modeling and third approach is Close range photogrammetry based modeling. Literature study shows that till date, there is no complete solution available to create complete 3D city model by using images. These image based methods also have limitations This paper gives a new approach towards image based virtual 3D city modeling by using close range photogrammetry. This approach is divided into three sections. First, data acquisition process, second is 3D data processing, and third is data combination process. In data acquisition process, a multi-camera setup developed and used for video recording of an area. Image frames created from video data. Minimum required and suitable video image frame selected for 3D processing. In second section, based on close range photogrammetric principles and computer vision techniques, 3D model of area created. In third section, this 3D model exported to adding and merging of other pieces of large area. Scaling and alignment of 3D model was done. After applying the texturing and rendering on this model, a final photo-realistic textured 3D model created. This 3D model transferred into walk-through model or in movie form. Most of the processing steps are automatic. So this method is cost effective and less laborious. Accuracy of this model is good. For this research work, study area is the campus of department of civil engineering, Indian Institute of Technology, Roorkee. This campus acts as a prototype for city. Aerial photography is restricted in many country

  11. ICER-3D Hyperspectral Image Compression Software

    NASA Technical Reports Server (NTRS)

    Xie, Hua; Kiely, Aaron; Klimesh, matthew; Aranki, Nazeeh

    2010-01-01

    Software has been developed to implement the ICER-3D algorithm. ICER-3D effects progressive, three-dimensional (3D), wavelet-based compression of hyperspectral images. If a compressed data stream is truncated, the progressive nature of the algorithm enables reconstruction of hyperspectral data at fidelity commensurate with the given data volume. The ICER-3D software is capable of providing either lossless or lossy compression, and incorporates an error-containment scheme to limit the effects of data loss during transmission. The compression algorithm, which was derived from the ICER image compression algorithm, includes wavelet-transform, context-modeling, and entropy coding subalgorithms. The 3D wavelet decomposition structure used by ICER-3D exploits correlations in all three dimensions of sets of hyperspectral image data, while facilitating elimination of spectral ringing artifacts, using a technique summarized in "Improving 3D Wavelet-Based Compression of Spectral Images" (NPO-41381), NASA Tech Briefs, Vol. 33, No. 3 (March 2009), page 7a. Correlation is further exploited by a context-modeling subalgorithm, which exploits spectral dependencies in the wavelet-transformed hyperspectral data, using an algorithm that is summarized in "Context Modeler for Wavelet Compression of Hyperspectral Images" (NPO-43239), which follows this article. An important feature of ICER-3D is a scheme for limiting the adverse effects of loss of data during transmission. In this scheme, as in the similar scheme used by ICER, the spatial-frequency domain is partitioned into rectangular error-containment regions. In ICER-3D, the partitions extend through all the wavelength bands. The data in each partition are compressed independently of those in the other partitions, so that loss or corruption of data from any partition does not affect the other partitions. Furthermore, because compression is progressive within each partition, when data are lost, any data from that partition received

  12. Future of photorefractive based holographic 3D display

    NASA Astrophysics Data System (ADS)

    Blanche, P.-A.; Bablumian, A.; Voorakaranam, R.; Christenson, C.; Lemieux, D.; Thomas, J.; Norwood, R. A.; Yamamoto, M.; Peyghambarian, N.

    2010-02-01

    The very first demonstration of our refreshable holographic display based on photorefractive polymer was published in Nature early 20081. Based on the unique properties of a new organic photorefractive material and the holographic stereography technique, this display addressed a gap between large static holograms printed in permanent media (photopolymers) and small real time holographic systems like the MIT holovideo. Applications range from medical imaging to refreshable maps and advertisement. Here we are presenting several technical solutions for improving the performance parameters of the initial display from an optical point of view. Full color holograms can be generated thanks to angular multiplexing, the recording time can be reduced from minutes to seconds with a pulsed laser, and full parallax hologram can be recorded in a reasonable time thanks to parallel writing. We also discuss the future of such a display and the possibility of video rate.

  13. Building a 3D scanner system based on monocular vision.

    PubMed

    Zhang, Zhiyi; Yuan, Lin

    2012-04-10

    This paper proposes a three-dimensional scanner system, which is built by using an ingenious geometric construction method based on monocular vision. The system is simple, low cost, and easy to use, and the measurement results are very precise. To build it, one web camera, one handheld linear laser, and one background calibration board are required. The experimental results show that the system is robust and effective, and the scanning precision can be satisfied for normal users.

  14. 3D Mesh Segmentation Based on Markov Random Fields and Graph Cuts

    NASA Astrophysics Data System (ADS)

    Shi, Zhenfeng; Le, Dan; Yu, Liyang; Niu, Xiamu

    3D Mesh segmentation has become an important research field in computer graphics during the past few decades. Many geometry based and semantic oriented approaches for 3D mesh segmentation has been presented. However, only a few algorithms based on Markov Random Field (MRF) has been presented for 3D object segmentation. In this letter, we present a definition of mesh segmentation according to the labeling problem. Inspired by the capability of MRF combining the geometric information and the topology information of a 3D mesh, we propose a novel 3D mesh segmentation model based on MRF and Graph Cuts. Experimental results show that our MRF-based schema achieves an effective segmentation.

  15. Wavelet-based Poisson Solver for use in Particle-In-CellSimulations

    SciTech Connect

    Terzic, B.; Mihalcea, D.; Bohn, C.L.; Pogorelov, I.V.

    2005-05-13

    We report on a successful implementation of a wavelet based Poisson solver for use in 3D particle-in-cell (PIC) simulations. One new aspect of our algorithm is its ability to treat the general(inhomogeneous) Dirichlet boundary conditions (BCs). The solver harnesses advantages afforded by the wavelet formulation, such as sparsity of operators and data sets, existence of effective preconditioners, and the ability simultaneously to remove numerical noise and further compress relevant data sets. Having tested our method as a stand-alone solver on two model problems, we merged it into IMPACT-T to obtain a fully functional serial PIC code. We present and discuss preliminary results of application of the new code to the modeling of the Fermilab/NICADD and AES/JLab photoinjectors.

  16. Comprehensive evaluation of latest 2D/3D monitors and comparison to a custom-built 3D mirror-based display in laparoscopic surgery

    NASA Astrophysics Data System (ADS)

    Wilhelm, Dirk; Reiser, Silvano; Kohn, Nils; Witte, Michael; Leiner, Ulrich; Mühlbach, Lothar; Ruschin, Detlef; Reiner, Wolfgang; Feussner, Hubertus

    2014-03-01

    Though theoretically superior, 3D video systems did not yet achieve a breakthrough in laparoscopic surgery. Furthermore, visual alterations, such as eye strain, diplopia and blur have been associated with the use of stereoscopic systems. Advancements in display and endoscope technology motivated a re-evaluation of such findings. A randomized study on 48 test subjects was conducted to investigate whether surgeons can benefit from using most current 3D visualization systems. Three different 3D systems, a glasses-based 3D monitor, an autostereoscopic display and a mirror-based theoretically ideal 3D display were compared to a state-of-the-art 2D HD system. The test subjects split into a novice and an expert surgeon group, which high experience in laparoscopic procedures. Each of them had to conduct a well comparable laparoscopic suturing task. Multiple performance parameters like task completion time and the precision of stitching were measured and compared. Electromagnetic tracking provided information on the instruments path length, movement velocity and economy. The NASA task load index was used to assess the mental work load. Subjective ratings were added to assess usability, comfort and image quality of each display. Almost all performance parameters were superior for the 3D glasses-based display as compared to the 2D and the autostereoscopic one, but were often significantly exceeded by the mirror-based 3D display. Subjects performed the task at average 20% faster and with a higher precision. Work-load parameters did not show significant differences. Experienced and non-experienced laparoscopists profited equally from 3D. The 3D mirror system gave clear evidence for additional potential of 3D visualization systems with higher resolution and motion parallax presentation.

  17. The Martian Water Cycle Based on 3-D Modeling

    NASA Technical Reports Server (NTRS)

    Houben, H.; Haberle, R. M.; Joshi, M. M.

    1999-01-01

    Understanding the distribution of Martian water is a major goal of the Mars Surveyor program. However, until the bulk of the data from the nominal missions of TES, PMIRR, GRS, MVACS, and the DS2 probes are available, we are bound to be in a state where much of our knowledge of the seasonal behavior of water is based on theoretical modeling. We therefore summarize the results of this modeling at the present time. The most complete calculations come from a somewhat simplified treatment of the Martian climate system which is capable of simulating many decades of weather. More elaborate meteorological models are now being applied to study of the problem. The results show a high degree of consistency with observations of aspects of the Martian water cycle made by Viking MAWD, a large number of ground-based measurements of atmospheric column water vapor, studies of Martian frosts, and the widespread occurrence of water ice clouds. Additional information is contained in the original extended abstract.

  18. 3D, wideband vibro-impacting-based piezoelectric energy harvester

    SciTech Connect

    Yu, Qiangmo; Yang, Jin Yue, Xihai; Yang, Aichao; Zhao, Jiangxin; Zhao, Nian; Wen, Yumei; Li, Ping

    2015-04-15

    An impacting-based piezoelectric energy harvester was developed to address the limitations of the existing approaches in single-dimensional operation as well as a narrow working bandwidth. In the harvester, a spiral cylindrical spring rather than the conventional thin cantilever beam was utilized to extract the external vibration with arbitrary directions, which has the capability to impact the surrounding piezoelectric beams to generate electricity. And the introduced vibro-impacting between the spiral cylindrical spring and multi-piezoelectric-beams resulted in not only a three-dimensional response to external vibration, but also a bandwidth-broadening behavior. The experimental results showed that each piezoelectric beam exhibited a maximum bandwidth of 8 Hz and power of 41 μW with acceleration of 1 g (with g=9.8 ms{sup −2}) along the z-axis, and corresponding average values of 5 Hz and 45 μW with acceleration of 0.6 g in the x-y plane. .

  19. Literary and Historical 3D Digital Game-Based Learning: Design Guidelines

    ERIC Educational Resources Information Center

    Neville, David O.; Shelton, Brett E.

    2010-01-01

    As 3D digital game-based learning (3D-DGBL) for the teaching of literature and history gradually gains acceptance, important questions will need to be asked regarding its method of design, development, and deployment. This article offers a synthesis of contemporary pedagogical, instructional design, new media, and literary-historical theories to…

  20. Highly Stretchable and UV Curable Elastomers for Digital Light Processing Based 3D Printing.

    PubMed

    Patel, Dinesh K; Sakhaei, Amir Hosein; Layani, Michael; Zhang, Biao; Ge, Qi; Magdassi, Shlomo

    2017-04-01

    Stretchable UV-curable (SUV) elastomers can be stretched by up to 1100% and are suitable for digital-light-processing (DLP)-based 3D-printing technology. DLP printing of these SUV elastomers enables the direct creation of highly deformable complex 3D hollow structures such as balloons, soft actuators, grippers, and buckyball electronical switches.

  1. 3D Printing Factors Important for the Fabrication of Polyvinylalcohol Filament-Based Tablets.

    PubMed

    Tagami, Tatsuaki; Fukushige, Kaori; Ogawa, Emi; Hayashi, Naomi; Ozeki, Tetsuya

    2017-01-01

    Three-dimensional (3D) printers have been applied in many fields, including engineering and the medical sciences. In the pharmaceutical field, approval of the first 3D-printed tablet by the U.S. Food and Drug Administration in 2015 has attracted interest in the manufacture of tablets and drugs by 3D printing techniques as a means of delivering tailor-made drugs in the future. In current study, polyvinylalcohol (PVA)-based tablets were prepared using a fused-deposition-modeling-type 3D printer and the effect of 3D printing conditions on tablet production was investigated. Curcumin, a model drug/fluorescent marker, was loaded into PVA-filament. We found that several printing parameters, such as the rate of extruding PVA (flow rate), can affect the formability of the resulting PVA-tablets. The 3D-printing temperature is controlled by heating the print nozzle and was shown to affect the color of the tablets and their curcumin content. PVA-based infilled tablets with different densities were prepared by changing the fill density as a printing parameter. Tablets with lower fill density floated in an aqueous solution and their curcumin content tended to dissolve faster. These findings will be useful in developing drug-loaded PVA-based 3D objects and other polymer-based articles prepared using fused-deposition-modeling-type 3D printers.

  2. 3D modeling of geological anomalies based on segmentation of multiattribute fusion

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-Ning; Song, Cheng-Yun; Li, Zhi-Yong; Cai, Han-Peng; Yao, Xing-Miao; Hu, Guang-Min

    2016-09-01

    3D modeling of geological bodies based on 3D seismic data is used to define the shape and volume of the bodies, which then can be directly applied to reservoir prediction, reserve estimation, and exploration. However, multiattributes are not effectively used in 3D modeling. To solve this problem, we propose a novel method for building of 3D model of geological anomalies based on the segmentation of multiattribute fusion. First, we divide the seismic attributes into edge- and region-based seismic attributes. Then, the segmentation model incorporating the edge- and region-based models is constructed within the levelset-based framework. Finally, the marching cubes algorithm is adopted to extract the zero level set based on the segmentation results and build the 3D model of the geological anomaly. Combining the edge-and region-based attributes to build the segmentation model, we satisfy the independence requirement and avoid the problem of insufficient data of single seismic attribute in capturing the boundaries of geological anomalies. We apply the proposed method to seismic data from the Sichuan Basin in southwestern China and obtain 3D models of caves and channels. Compared with 3D models obtained based on single seismic attributes, the results are better agreement with reality.

  3. Image denoising based on wavelets and multifractals for singularity detection.

    PubMed

    Zhong, Junmei; Ning, Ruola

    2005-10-01

    This paper presents a very efficient algorithm for image denoising based on wavelets and multifractals for singularity detection. A challenge of image denoising is how to preserve the edges of an image when reducing noise. By modeling the intensity surface of a noisy image as statistically self-similar multifractal processes and taking advantage of the multiresolution analysis with wavelet transform to exploit the local statistical self-similarity at different scales, the pointwise singularity strength value characterizing the local singularity at each scale was calculated. By thresholding the singularity strength, wavelet coefficients at each scale were classified into two categories: the edge-related and regular wavelet coefficients and the irregular coefficients. The irregular coefficients were denoised using an approximate minimum mean-squared error (MMSE) estimation method, while the edge-related and regular wavelet coefficients were smoothed using the fuzzy weighted mean (FWM) filter aiming at preserving the edges and details when reducing noise. Furthermore, to make the FWM-based filtering more efficient for noise reduction at the lowest decomposition level, the MMSE-based filtering was performed as the first pass of denoising followed by performing the FWM-based filtering. Experimental results demonstrated that this algorithm could achieve both good visual quality and high PSNR for the denoised images.

  4. 3D-shape-based retrieval within the MPEG-7 framework

    NASA Astrophysics Data System (ADS)

    Zaharia, Titus; Preteux, Francoise J.

    2001-05-01

    Because of the continuous development of multimedia technologies, virtual worlds and augmented reality, 3D contents become a common feature of the today information systems. Hence, standardizing tools for content-based indexing of visual data is a key issue for computer vision related applications. Within the framework of the future MPEG-7 standard, tools for intelligent content-based access to 3D information, targeting applications such as search and retrieval and browsing of 3D model databases, have been recently considered and evaluated. In this paper, we present the 3D Shape Spectrum Descriptor (3D SSD), recently adopted within the current MPEG-7 Committee Draft (CD). The proposed descriptor aims at providing an intrinsic shape description of a 3D mesh and is defined as the distribution of the shape index over the entire mesh. The shape index is a local geometric attribute of a 3D surface, expressed as the angular coordinate of a polar representation of the principal curvature vector. Experimental results have been carried out upon the MPEG-7 3D model database consisting of about 1300 meshes in VRML 2.0 format. Objective retrieval results, based upon the definition of a ground truth subset, are reported in terms of Bull Eye Percentage (BEP) score.

  5. Electrochemical signal amplification for immunosensor based on 3D interdigitated array electrodes.

    PubMed

    Han, Donghoon; Kim, Yang-Rae; Kang, Chung Mu; Chung, Taek Dong

    2014-06-17

    We devised an electrochemical redox cycling based on three-dimensional interdigitated array (3D IDA) electrodes for signal amplification to enhance the sensitivity of chip-based immunosensors. The 3D IDA consists of two closely spaced parallel indium tin oxide (ITO) electrodes that are positioned not only on the bottom but also the ceiling, facing each other along a microfluidic channel. We investigated the signal intensities from various geometric configurations: Open-2D IDA, Closed-2D IDA, and 3D IDA through electrochemical experiments and finite-element simulations. The 3D IDA among the four different systems exhibited the greatest signal amplification resulting from efficient redox cycling of electroactive species confined in the microchannel so that the faradaic current was augmented by a factor of ∼100. We exploited the enhanced sensitivity of the 3D IDA to build up a chronocoulometric immunosensing platform based on the sandwich enzyme-linked immunosorbent assay (ELISA) protocol. The mouse IgGs on the 3D IDA showed much lower detection limits than on the Closed-2D IDA. The detection limit for mouse IgG measured using the 3D IDA was ∼10 fg/mL, while it was ∼100 fg/mL for the Closed-2D IDA. Moreover, the proposed immunosensor system with the 3D IDA successfully worked for clinical analysis as shown by the sensitive detection of cardiac troponin I in human serum down to 100 fg/mL.

  6. Predicting apple tree leaf nitrogen content based on hyperspectral applying wavelet and wavelet packet analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Yao; Zheng, Lihua; Li, Minzan; Deng, Xiaolei; Sun, Hong

    2012-11-01

    The visible and NIR spectral reflectance were measured for apple leaves by using a spectrophotometer in fruit-bearing, fruit-falling and fruit-maturing period respectively, and the nitrogen content of each sample was measured in the lab. The analysis of correlation between nitrogen content of apple tree leaves and their hyperspectral data was conducted. Then the low frequency signal and high frequency noise reduction signal were extracted by using wavelet packet decomposition algorithm. At the same time, the original spectral reflectance was denoised taking advantage of the wavelet filtering technology. And then the principal components spectra were collected after PCA (Principal Component Analysis). It was known that the model built based on noise reduction principal components spectra reached higher accuracy than the other three ones in fruit-bearing period and physiological fruit-maturing period. Their calibration R2 reached 0.9529 and 0.9501, and validation R2 reached 0.7285 and 0.7303 respectively. While in the fruit-falling period the model based on low frequency principal components spectra reached the highest accuracy, and its calibration R2 reached 0.9921 and validation R2 reached 0.6234. The results showed that it was an effective way to improve ability of predicting apple tree nitrogen content based on hyperspectral analysis by using wavelet packet algorithm.

  7. FAST WAVELET-BASED SINGLE-PARTICLE RECONSTRUCTION IN CRYO-EM.

    PubMed

    Vonesch, Cédric; Wang, Lanhui; Shkolnisky, Yoel; Singer, Amit

    2011-06-09

    This paper presents a novel algorithm for the 3D tomographic inversion problem that arises in single-particle electron cryo-microscopy (Cryo-EM). It is based on two key components: 1) a variational formulation that promotes sparsity in the wavelet domain and 2) the Toeplitz structure of the combined projection/back-projection operator. The first idea has proven to be very effective for the recovery of piecewise-smooth signals, which is confirmed by our numerical experiments. The second idea allows for a computationally efficient implementation of the reconstruction procedure, using only one circulant convolution per iteration.

  8. A Wavelet-Based Methodology for Grinding Wheel Condition Monitoring

    SciTech Connect

    Liao, T. W.; Ting, C.F.; Qu, Jun; Blau, Peter Julian

    2007-01-01

    Grinding wheel surface condition changes as more material is removed. This paper presents a wavelet-based methodology for grinding wheel condition monitoring based on acoustic emission (AE) signals. Grinding experiments in creep feed mode were conducted to grind alumina specimens with a resinoid-bonded diamond wheel using two different conditions. During the experiments, AE signals were collected when the wheel was 'sharp' and when the wheel was 'dull'. Discriminant features were then extracted from each raw AE signal segment using the discrete wavelet decomposition procedure. An adaptive genetic clustering algorithm was finally applied to the extracted features in order to distinguish different states of grinding wheel condition. The test results indicate that the proposed methodology can achieve 97% clustering accuracy for the high material removal rate condition, 86.7% for the low material removal rate condition, and 76.7% for the combined grinding conditions if the base wavelet, the decomposition level, and the GA parameters are properly selected.

  9. Midsagittal plane extraction from brain images based on 3D SIFT

    NASA Astrophysics Data System (ADS)

    Wu, Huisi; Wang, Defeng; Shi, Lin; Wen, Zhenkun; Ming, Zhong

    2014-03-01

    Midsagittal plane (MSP) extraction from 3D brain images is considered as a promising technique for human brain symmetry analysis. In this paper, we present a fast and robust MSP extraction method based on 3D scale-invariant feature transform (SIFT). Unlike the existing brain MSP extraction methods, which mainly rely on the gray similarity, 3D edge registration or parameterized surface matching to determine the fissure plane, our proposed method is based on distinctive 3D SIFT features, in which the fissure plane is determined by parallel 3D SIFT matching and iterative least-median of squares plane regression. By considering the relative scales, orientations and flipped descriptors between two 3D SIFT features, we propose a novel metric to measure the symmetry magnitude for 3D SIFT features. By clustering and indexing the extracted SIFT features using a k-dimensional tree (KD-tree) implemented on graphics processing units, we can match multiple pairs of 3D SIFT features in parallel and solve the optimal MSP on-the-fly. The proposed method is evaluated by synthetic and in vivo datasets, of normal and pathological cases, and validated by comparisons with the state-of-the-art methods. Experimental results demonstrated that our method has achieved a real-time performance with better accuracy yielding an average yaw angle error below 0.91° and an average roll angle error no more than 0.89°.

  10. Some Contributions to Wavelet Based Image Coding

    DTIC Science & Technology

    2000-07-01

    MSE or PSNR. However, it is noted that JZW does not implement the embedded property as in EZW and SPIHT and that the embedded property can be...achieved by passing the JND quantized wavelet coefficients to EZW or SPIHT. It is noted that the lowest frequency (the coarsest scale) band (LL band) is the...other higher frequency subbands can be efficiently encoded using our zero-tree encoding scheme which is derived from EZW and [improved version of EZW by

  11. Research on gaze-based interaction to 3D display system

    NASA Astrophysics Data System (ADS)

    Kwon, Yong-Moo; Jeon, Kyeong-Won; Kim, Sung-Kyu

    2006-10-01

    There have been reported several researches on gaze tracking techniques using monocular camera or stereo camera. The most popular used gaze estimation techniques are based on PCCR (Pupil Center & Cornea Reflection). These techniques are for gaze tracking for 2D screen or images. In this paper, we address the gaze-based 3D interaction to stereo image for 3D virtual space. To the best of our knowledge, our paper first addresses the 3D gaze interaction techniques to 3D display system. Our research goal is the estimation of both of gaze direction and gaze depth. Until now, the most researches are focused on only gaze direction for the application to 2D display system. It should be noted that both of gaze direction and gaze depth should be estimated for the gaze-based interaction in 3D virtual space. In this paper, we address the gaze-based 3D interaction techniques with glassless stereo display. The estimation of gaze direction and gaze depth from both eyes is a new important research topic for gaze-based 3D interaction. We present our approach for the estimation of gaze direction and gaze depth and show experimentation results.

  12. Comparison Between Two Generic 3d Building Reconstruction Approaches - Point Cloud Based VS. Image Processing Based

    NASA Astrophysics Data System (ADS)

    Dahlke, D.; Linkiewicz, M.

    2016-06-01

    This paper compares two generic approaches for the reconstruction of buildings. Synthesized and real oblique and vertical aerial imagery is transformed on the one hand into a dense photogrammetric 3D point cloud and on the other hand into photogrammetric 2.5D surface models depicting a scene from different cardinal directions. One approach evaluates the 3D point cloud statistically in order to extract the hull of structures, while the other approach makes use of salient line segments in 2.5D surface models, so that the hull of 3D structures can be recovered. With orders of magnitudes more analyzed 3D points, the point cloud based approach is an order of magnitude more accurate for the synthetic dataset compared to the lower dimensioned, but therefor orders of magnitude faster, image processing based approach. For real world data the difference in accuracy between both approaches is not significant anymore. In both cases the reconstructed polyhedra supply information about their inherent semantic and can be used for subsequent and more differentiated semantic annotations through exploitation of texture information.

  13. Wavelet-Based Speech Enhancement Using Time-Frequency Adaptation

    NASA Astrophysics Data System (ADS)

    Wang, Kun-Ching

    2003-12-01

    Wavelet denoising is commonly used for speech enhancement because of the simplicity of its implementation. However, the conventional methods generate the presence of musical residual noise while thresholding the background noise. The unvoiced components of speech are often eliminated from this method. In this paper, a novel algorithm of wavelet coefficient threshold (WCT) based on time-frequency adaptation is proposed. In addition, an unvoiced speech enhancement algorithm is also integrated into the system to improve the intelligibility of speech. The wavelet coefficient threshold (WCT) of each subband is first temporally adjusted according to the value of a posterior signal-to-noise ratio (SNR). To prevent the degradation of unvoiced sounds during noise, the algorithm utilizes a simple speech/noise detector (SND) and further divides speech signal into unvoiced and voiced sounds. Then, we apply appropriate wavelet thresholding according to voiced/unvoiced (V/U) decision. Based on the masking properties of human auditory system, a perceptual gain factor is adopted into wavelet thresholding for suppressing musical residual noise. Simulation results show that the proposed method is capable of reducing noise with little speech degradation and the overall performance is superior to several competitive methods.

  14. The National 3-D Geospatial Information Web-Based Service of Korea

    NASA Astrophysics Data System (ADS)

    Lee, D. T.; Kim, C. W.; Kang, I. G.

    2013-09-01

    3D geospatial information systems should provide efficient spatial analysis tools and able to use all capabilities of the third dimension, and a visualization. Currently, many human activities make steps toward the third dimension like land use, urban and landscape planning, cadastre, environmental monitoring, transportation monitoring, real estate market, military applications, etc. To reflect this trend, the Korean government has been started to construct the 3D geospatial data and service platform. Since the geospatial information was introduced in Korea, the construction of geospatial information (3D geospatial information, digital maps, aerial photographs, ortho photographs, etc.) has been led by the central government. The purpose of this study is to introduce the Korean government-lead 3D geospatial information web-based service for the people who interested in this industry and we would like to introduce not only the present conditions of constructed 3D geospatial data but methodologies and applications of 3D geospatial information. About 15% (about 3,278.74 km2) of the total urban area's 3D geospatial data have been constructed by the national geographic information institute (NGII) of Korea from 2005 to 2012. Especially in six metropolitan cities and Dokdo (island belongs to Korea) on level of detail (LOD) 4 which is photo-realistic textured 3D models including corresponding ortho photographs were constructed in 2012. In this paper, we represented web-based 3D map service system composition and infrastructure and comparison of V-world with Google Earth service will be presented. We also represented Open API based service cases and discussed about the protection of location privacy when we construct 3D indoor building models. In order to prevent an invasion of privacy, we processed image blurring, elimination and camouflage. The importance of public-private cooperation and advanced geospatial information policy is emphasized in Korea. Thus, the progress of

  15. Implementing a global DEM database on the sphere based on spherical wavelets

    NASA Astrophysics Data System (ADS)

    Zhao, Di; Zhao, Xuesheng; Shan, Shigang; Yao, Liangjun

    2010-11-01

    Wavelets have been proven to be an exceedingly powerful and highly efficient tool for fast computational algorithms in the fields of image data analysis and compression. Traditionally, the classical constructed wavelets are often employed to Euclidean infinite domains (such as the real line R and plane R2). In this paper, a spherical wavelet constructed for discrete DEM data based on the sphere is approached. Firstly, the discrete biorthogonal spherical wavelet with custom properties is constructed with the lifting scheme based on wavelet toolbox in Matlab. Then, the decomposition and reconstruction algorithms are proposed for efficient computation and the related wavelet coefficients are obtained. Finally, different precise images are displayed and analyzed at the different percentage of wavelet coefficients. The efficiency of this spherical wavelet algorithm is tested by using the GTOPO30 DEM data and the results show that at the same precision, the spherical wavelet algorithm consumes smaller storage volume. The results are good and acceptable.

  16. Implementing a global DEM database on the sphere based on spherical wavelets

    NASA Astrophysics Data System (ADS)

    Zhao, Di; Zhao, Xuesheng; Shan, Shigang; Yao, Liangjun

    2009-09-01

    Wavelets have been proven to be an exceedingly powerful and highly efficient tool for fast computational algorithms in the fields of image data analysis and compression. Traditionally, the classical constructed wavelets are often employed to Euclidean infinite domains (such as the real line R and plane R2). In this paper, a spherical wavelet constructed for discrete DEM data based on the sphere is approached. Firstly, the discrete biorthogonal spherical wavelet with custom properties is constructed with the lifting scheme based on wavelet toolbox in Matlab. Then, the decomposition and reconstruction algorithms are proposed for efficient computation and the related wavelet coefficients are obtained. Finally, different precise images are displayed and analyzed at the different percentage of wavelet coefficients. The efficiency of this spherical wavelet algorithm is tested by using the GTOPO30 DEM data and the results show that at the same precision, the spherical wavelet algorithm consumes smaller storage volume. The results are good and acceptable.

  17. Fourier-based reconstruction for fully 3-D PET: optimization of interpolation parameters.

    PubMed

    Matej, Samuel; Kazantsev, Ivan G

    2006-07-01

    Fourier-based approaches for three-dimensional (3-D) reconstruction are based on the relationship between the 3-D Fourier transform (FT) of the volume and the two-dimensional (2-D) FT of a parallel-ray projection of the volume. The critical step in the Fourier-based methods is the estimation of the samples of the 3-D transform of the image from the samples of the 2-D transforms of the projections on the planes through the origin of Fourier space, and vice versa for forward-projection (reprojection). The Fourier-based approaches have the potential for very fast reconstruction, but their straightforward implementation might lead to unsatisfactory results if careful attention is not paid to interpolation and weighting functions. In our previous work, we have investigated optimal interpolation parameters for the Fourier-based forward and back-projectors for iterative image reconstruction. The optimized interpolation kernels were shown to provide excellent quality comparable to the ideal sinc interpolator. This work presents an optimization of interpolation parameters of the 3-D direct Fourier method with Fourier reprojection (3D-FRP) for fully 3-D positron emission tomography (PET) data with incomplete oblique projections. The reprojection step is needed for the estimation (from an initial image) of the missing portions of the oblique data. In the 3D-FRP implementation, we use the gridding interpolation strategy, combined with proper weighting approaches in the transform and image domains. We have found that while the 3-D reprojection step requires similar optimal interpolation parameters as found in our previous studies on Fourier-based iterative approaches, the optimal interpolation parameters for the main 3D-FRP reconstruction stage are quite different. Our experimental results confirm that for the optimal interpolation parameters a very good image accuracy can be achieved even without any extra spectral oversampling, which is a common practice to decrease errors

  18. Binary 3D image interpolation algorithm based global information and adaptive curves fitting

    NASA Astrophysics Data System (ADS)

    Zhang, Tian-yi; Zhang, Jin-hao; Guan, Xiang-chen; Li, Qiu-ping; He, Meng

    2013-08-01

    Interpolation is a necessary processing step in 3-D reconstruction because of the non-uniform resolution. Conventional interpolation methods simply use two slices to obtain the missing slices between the two slices .when the key slice is missing, those methods may fail to recover it only employing the local information .And the surface of 3D object especially for the medical tissues may be highly complicated, so a single interpolation can hardly get high-quality 3D image. We propose a novel binary 3D image interpolation algorithm. The proposed algorithm takes advantages of the global information. It chooses the best curve adaptively from lots of curves based on the complexity of the surface of 3D object. The results of this algorithm are compared with other interpolation methods on artificial objects and real breast cancer tumor to demonstrate the excellent performance.

  19. 3D Building Models Segmentation Based on K-Means++ Cluster Analysis

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Mao, B.

    2016-10-01

    3D mesh model segmentation is drawing increasing attentions from digital geometry processing field in recent years. The original 3D mesh model need to be divided into separate meaningful parts or surface patches based on certain standards to support reconstruction, compressing, texture mapping, model retrieval and etc. Therefore, segmentation is a key problem for 3D mesh model segmentation. In this paper, we propose a method to segment Collada (a type of mesh model) 3D building models into meaningful parts using cluster analysis. Common clustering methods segment 3D mesh models by K-means, whose performance heavily depends on randomized initial seed points (i.e., centroid) and different randomized centroid can get quite different results. Therefore, we improved the existing method and used K-means++ clustering algorithm to solve this problem. Our experiments show that K-means++ improves both the speed and the accuracy of K-means, and achieve good and meaningful results.

  20. 3D imaging of telomeres and nuclear architecture: An emerging tool of 3D nano-morphology-based diagnosis.

    PubMed

    Knecht, Hans; Mai, Sabine

    2011-04-01

    Patient samples are evaluated by experienced pathologists whose diagnosis guides treating physicians. Pathological diagnoses are complex and often assisted by the application of specific tissue markers. However, cases still exist where pathologists cannot distinguish between closely related entities or determine the aggressiveness of the disease they identify under the microscope. This is due to the absence of reliable markers that define diagnostic subgroups in several cancers. Three-dimensional (3D) imaging of nuclear telomere signatures is emerging as a new tool that may change this situation offering new opportunities to the patients. This article will review current and future avenues in the assessment of diagnostic patient samples.

  1. The design and implementation of stereoscopic 3D scalable vector graphics based on WebKit

    NASA Astrophysics Data System (ADS)

    Liu, Zhongxin; Wang, Wenmin; Wang, Ronggang

    2014-03-01

    Scalable Vector Graphics (SVG), which is a language designed based on eXtensible Markup Language (XML), is used to describe basic shapes embedded in webpages, such as circles and rectangles. However, it can only depict 2D shapes. As a consequence, web pages using classical SVG can only display 2D shapes on a screen. With the increasing development of stereoscopic 3D (S3D) technology, binocular 3D devices have been widely used. Under this circumstance, we intend to extend the widely used web rendering engine WebKit to support the description and display of S3D webpages. Therefore, the extension of SVG is of necessity. In this paper, we will describe how to design and implement SVG shapes with stereoscopic 3D mode. Two attributes representing the depth and thickness are added to support S3D shapes. The elimination of hidden lines and hidden surfaces, which is an important process in this project, is described as well. The modification of WebKit is also discussed, which is made to support the generation of both left view and right view at the same time. As is shown in the result, in contrast to the 2D shapes generated by the Google Chrome web browser, the shapes got from our modified browser are in S3D mode. With the feeling of depth and thickness, the shapes seem to be real 3D objects away from the screen, rather than simple curves and lines as before.

  2. M3D (Media 3D): a new programming language for web-based virtual reality in E-Learning and Edutainment

    NASA Astrophysics Data System (ADS)

    Chakaveh, Sepideh; Skaley, Detlef; Laine, Patricia; Haeger, Ralf; Maad, Soha

    2003-01-01

    Today, interactive multimedia educational systems are well established, as they prove useful instruments to enhance one's learning capabilities. Hitherto, the main difficulty with almost all E-Learning systems was latent in the rich media implementation techniques. This meant that each and every system should be created individually as reapplying the media, be it only a part, or the whole content was not directly possible, as everything must be applied mechanically i.e. by hand. Consequently making E-learning systems exceedingly expensive to generate, both in time and money terms. Media-3D or M3D is a new platform independent programming language, developed at the Fraunhofer Institute Media Communication to enable visualisation and simulation of E-Learning multimedia content. M3D is an XML-based language, which is capable of distinguishing between the3D models from that of the 3D scenes, as well as handling provisions for animations, within the programme. Here we give a technical account of M3D programming language and briefly describe two specific application scenarios where M3D is applied to create virtual reality E-Learning content for training of technical personnel.

  3. Genome3D: a UK collaborative project to annotate genomic sequences with predicted 3D structures based on SCOP and CATH domains

    PubMed Central

    Lewis, Tony E.; Sillitoe, Ian; Andreeva, Antonina; Blundell, Tom L.; Buchan, Daniel W.A.; Chothia, Cyrus; Cuff, Alison; Dana, Jose M.; Filippis, Ioannis; Gough, Julian; Hunter, Sarah; Jones, David T.; Kelley, Lawrence A.; Kleywegt, Gerard J.; Minneci, Federico; Mitchell, Alex; Murzin, Alexey G.; Ochoa-Montaño, Bernardo; Rackham, Owen J. L.; Smith, James; Sternberg, Michael J. E.; Velankar, Sameer; Yeats, Corin; Orengo, Christine

    2013-01-01

    Genome3D, available at http://www.genome3d.eu, is a new collaborative project that integrates UK-based structural resources to provide a unique perspective on sequence–structure–function relationships. Leading structure prediction resources (DomSerf, FUGUE, Gene3D, pDomTHREADER, Phyre and SUPERFAMILY) provide annotations for UniProt sequences to indicate the locations of structural domains (structural annotations) and their 3D structures (structural models). Structural annotations and 3D model predictions are currently available for three model genomes (Homo sapiens, E. coli and baker’s yeast), and the project will extend to other genomes in the near future. As these resources exploit different strategies for predicting structures, the main aim of Genome3D is to enable comparisons between all the resources so that biologists can see where predictions agree and are therefore more trusted. Furthermore, as these methods differ in whether they build their predictions using CATH or SCOP, Genome3D also contains the first official mapping between these two databases. This has identified pairs of similar superfamilies from the two resources at various degrees of consensus (532 bronze pairs, 527 silver pairs and 370 gold pairs). PMID:23203986

  4. Wavelet-based analysis of circadian behavioral rhythms.

    PubMed

    Leise, Tanya L

    2015-01-01

    The challenging problems presented by noisy biological oscillators have led to the development of a great variety of methods for accurately estimating rhythmic parameters such as period and amplitude. This chapter focuses on wavelet-based methods, which can be quite effective for assessing how rhythms change over time, particularly if time series are at least a week in length. These methods can offer alternative views to complement more traditional methods of evaluating behavioral records. The analytic wavelet transform can estimate the instantaneous period and amplitude, as well as the phase of the rhythm at each time point, while the discrete wavelet transform can extract the circadian component of activity and measure the relative strength of that circadian component compared to those in other frequency bands. Wavelet transforms do not require the removal of noise or trend, and can, in fact, be effective at removing noise and trend from oscillatory time series. The Fourier periodogram and spectrogram are reviewed, followed by descriptions of the analytic and discrete wavelet transforms. Examples illustrate application of each method and their prior use in chronobiology is surveyed. Issues such as edge effects, frequency leakage, and implications of the uncertainty principle are also addressed.

  5. FGG-NUFFT-Based Method for Near-Field 3-D Imaging Using Millimeter Waves

    PubMed Central

    Kan, Yingzhi; Zhu, Yongfeng; Tang, Liang; Fu, Qiang; Pei, Hucheng

    2016-01-01

    In this paper, to deal with the concealed target detection problem, an accurate and efficient algorithm for near-field millimeter wave three-dimensional (3-D) imaging is proposed that uses a two-dimensional (2-D) plane antenna array. First, a two-dimensional fast Fourier transform (FFT) is performed on the scattered data along the antenna array plane. Then, a phase shift is performed to compensate for the spherical wave effect. Finally, fast Gaussian gridding based nonuniform FFT (FGG-NUFFT) combined with 2-D inverse FFT (IFFT) is performed on the nonuniform 3-D spatial spectrum in the frequency wavenumber domain to achieve 3-D imaging. The conventional method for near-field 3-D imaging uses Stolt interpolation to obtain uniform spatial spectrum samples and performs 3-D IFFT to reconstruct a 3-D image. Compared with the conventional method, our FGG-NUFFT based method is comparable in both efficiency and accuracy in the full sampled case and can obtain more accurate images with less clutter and fewer noisy artifacts in the down-sampled case, which are good properties for practical applications. Both simulation and experimental results demonstrate that the FGG-NUFFT-based near-field 3-D imaging algorithm can have better imaging performance than the conventional method for down-sampled measurements. PMID:27657066

  6. FGG-NUFFT-Based Method for Near-Field 3-D Imaging Using Millimeter Waves.

    PubMed

    Kan, Yingzhi; Zhu, Yongfeng; Tang, Liang; Fu, Qiang; Pei, Hucheng

    2016-09-19

    In this paper, to deal with the concealed target detection problem, an accurate and efficient algorithm for near-field millimeter wave three-dimensional (3-D) imaging is proposed that uses a two-dimensional (2-D) plane antenna array. First, a two-dimensional fast Fourier transform (FFT) is performed on the scattered data along the antenna array plane. Then, a phase shift is performed to compensate for the spherical wave effect. Finally, fast Gaussian gridding based nonuniform FFT (FGG-NUFFT) combined with 2-D inverse FFT (IFFT) is performed on the nonuniform 3-D spatial spectrum in the frequency wavenumber domain to achieve 3-D imaging. The conventional method for near-field 3-D imaging uses Stolt interpolation to obtain uniform spatial spectrum samples and performs 3-D IFFT to reconstruct a 3-D image. Compared with the conventional method, our FGG-NUFFT based method is comparable in both efficiency and accuracy in the full sampled case and can obtain more accurate images with less clutter and fewer noisy artifacts in the down-sampled case, which are good properties for practical applications. Both simulation and experimental results demonstrate that the FGG-NUFFT-based near-field 3-D imaging algorithm can have better imaging performance than the conventional method for down-sampled measurements.

  7. Adaptively wavelet-based image denoising algorithm with edge preserving

    NASA Astrophysics Data System (ADS)

    Tan, Yihua; Tian, Jinwen; Liu, Jian

    2006-02-01

    A new wavelet-based image denoising algorithm, which exploits the edge information hidden in the corrupted image, is presented. Firstly, a canny-like edge detector identifies the edges in each subband. Secondly, multiplying the wavelet coefficients in neighboring scales is implemented to suppress the noise while magnifying the edge information, and the result is utilized to exclude the fake edges. The isolated edge pixel is also identified as noise. Unlike the thresholding method, after that we use local window filter in the wavelet domain to remove noise in which the variance estimation is elaborated to utilize the edge information. This method is adaptive to local image details, and can achieve better performance than the methods of state of the art.

  8. Fruit bruise detection based on 3D meshes and machine learning technologies

    NASA Astrophysics Data System (ADS)

    Hu, Zilong; Tang, Jinshan; Zhang, Ping

    2016-05-01

    This paper studies bruise detection in apples using 3-D imaging. Bruise detection based on 3-D imaging overcomes many limitations of bruise detection based on 2-D imaging, such as low accuracy, sensitive to light condition, and so on. In this paper, apple bruise detection is divided into two parts: feature extraction and classification. For feature extraction, we use a framework that can directly extract local binary patterns from mesh data. For classification, we studies support vector machine. Bruise detection using 3-D imaging is compared with bruise detection using 2-D imaging. 10-fold cross validation is used to evaluate the performance of the two systems. Experimental results show that bruise detection using 3-D imaging can achieve better classification accuracy than bruise detection based on 2-D imaging.

  9. Adaptive wavelet-based recognition of oscillatory patterns on electroencephalograms

    NASA Astrophysics Data System (ADS)

    Nazimov, Alexey I.; Pavlov, Alexey N.; Hramov, Alexander E.; Grubov, Vadim V.; Koronovskii, Alexey A.; Sitnikova, Evgenija Y.

    2013-02-01

    The problem of automatic recognition of specific oscillatory patterns on electroencephalograms (EEG) is addressed using the continuous wavelet-transform (CWT). A possibility of improving the quality of recognition by optimizing the choice of CWT parameters is discussed. An adaptive approach is proposed to identify sleep spindles (SS) and spike wave discharges (SWD) that assumes automatic selection of CWT-parameters reflecting the most informative features of the analyzed time-frequency structures. Advantages of the proposed technique over the standard wavelet-based approaches are considered.

  10. Wavelet-based image compression using fixed residual value

    NASA Astrophysics Data System (ADS)

    Muzaffar, Tanzeem; Choi, Tae-Sun

    2000-12-01

    Wavelet based compression is getting popular due to its promising compaction properties at low bitrate. Zerotree wavelet image coding scheme efficiently exploits multi-level redundancy present in transformed data to minimize coding bits. In this paper, a new technique is proposed to achieve high compression by adding new zerotree and significant symbols to original EZW coder. Contrary to four symbols present in basic EZW scheme, modified algorithm uses eight symbols to generate fewer bits for a given data. Subordinate pass of EZW is eliminated and replaced with fixed residual value transmission for easy implementation. This modification simplifies the coding technique as well and speeds up the process, retaining the property of embeddedness.

  11. Object-based wavelet compression using coefficient selection

    NASA Astrophysics Data System (ADS)

    Zhao, Lifeng; Kassim, Ashraf A.

    1998-12-01

    In this paper, we present a novel approach to code image regions of arbitrary shapes. The proposed algorithm combines a coefficient selection scheme with traditional wavelet compression for coding arbitrary regions and uses a shape adaptive embedded zerotree wavelet coding (SA-EZW) to quantize the selected coefficients. Since the shape information is implicitly encoded by the SA-EZW, our decoder can reconstruct the arbitrary region without separate shape coding. This makes the algorithm simple to implement and avoids the problem of contour coding. Our algorithm also provides a sufficient framework to address content-based scalability and improved coding efficiency as described by MPEG-4.

  12. Fish body surface data measurement based on 3D digital image correlation

    NASA Astrophysics Data System (ADS)

    Jiang, Ming; Qian, Chen; Yang, Wenkai

    2016-01-01

    To film the moving fish in the glass tank, light will be bent at the interface of air and glass, glass and water. Based on binocular stereo vision and refraction principle, we establish a mathematical model of 3D image correlation to reconstruct the 3D coordinates of samples in the water. Marking speckle in fish surface, a series of real-time speckle images of swimming fish will be obtained by two high-speed cameras, and instantaneous 3D shape, strain, displacement etc. of fish will be reconstructed.

  13. Optimized data processing for an optical 3D sensor based on flying triangulation

    NASA Astrophysics Data System (ADS)

    Ettl, Svenja; Arold, Oliver; Häusler, Gerd; Gurov, Igor; Volkov, Mikhail

    2013-05-01

    We present data processing methods for an optical 3D sensor based on the measurement principle "Flying Triangulation". The principle enables a motion-robust acquisition of the 3D shape of even complex objects: A hand-held sensor is freely guided around the object while real-time feedback of the measurement progress is delivered during the captioning. Although of high precision, the resulting 3D data usually may exhibit some weaknesses: e.g. outliers might be present and the data size might be too large. We describe the measurement principle and the data processing and conclude with measurement results.

  14. Fast and Precise 3D Fluorophore Localization based on Gradient Fitting

    PubMed Central

    Ma, Hongqiang; Xu, Jianquan; Jin, Jingyi; Gao, Ying; Lan, Li; Liu, Yang

    2015-01-01

    Astigmatism imaging approach has been widely used to encode the fluorophore’s 3D position in single-particle tracking and super-resolution localization microscopy. Here, we present a new high-speed localization algorithm based on gradient fitting to precisely decode the 3D subpixel position of the fluorophore. This algebraic algorithm determines the center of the fluorescent emitter by finding the position with the best-fit gradient direction distribution to the measured point spread function (PSF), and can retrieve the 3D subpixel position of the fluorophore in a single iteration. Through numerical simulation and experiments with mammalian cells, we demonstrate that our algorithm yields comparable localization precision to the traditional iterative Gaussian function fitting (GF) based method, while exhibits over two orders-of-magnitude faster execution speed. Our algorithm is a promising high-speed analyzing method for 3D particle tracking and super-resolution localization microscopy. PMID:26390959

  15. Event-Based 3D Motion Flow Estimation Using 4D Spatio Temporal Subspaces Properties.

    PubMed

    Ieng, Sio-Hoi; Carneiro, João; Benosman, Ryad B

    2016-01-01

    State of the art scene flow estimation techniques are based on projections of the 3D motion on image using luminance-sampled at the frame rate of the cameras-as the principal source of information. We introduce in this paper a pure time based approach to estimate the flow from 3D point clouds primarily output by neuromorphic event-based stereo camera rigs, or by any existing 3D depth sensor even if it does not provide nor use luminance. This method formulates the scene flow problem by applying a local piecewise regularization of the scene flow. The formulation provides a unifying framework to estimate scene flow from synchronous and asynchronous 3D point clouds. It relies on the properties of 4D space time using a decomposition into its subspaces. This method naturally exploits the properties of the neuromorphic asynchronous event based vision sensors that allows continuous time 3D point clouds reconstruction. The approach can also handle the motion of deformable object. Experiments using different 3D sensors are presented.

  16. Event-Based 3D Motion Flow Estimation Using 4D Spatio Temporal Subspaces Properties

    PubMed Central

    Ieng, Sio-Hoi; Carneiro, João; Benosman, Ryad B.

    2017-01-01

    State of the art scene flow estimation techniques are based on projections of the 3D motion on image using luminance—sampled at the frame rate of the cameras—as the principal source of information. We introduce in this paper a pure time based approach to estimate the flow from 3D point clouds primarily output by neuromorphic event-based stereo camera rigs, or by any existing 3D depth sensor even if it does not provide nor use luminance. This method formulates the scene flow problem by applying a local piecewise regularization of the scene flow. The formulation provides a unifying framework to estimate scene flow from synchronous and asynchronous 3D point clouds. It relies on the properties of 4D space time using a decomposition into its subspaces. This method naturally exploits the properties of the neuromorphic asynchronous event based vision sensors that allows continuous time 3D point clouds reconstruction. The approach can also handle the motion of deformable object. Experiments using different 3D sensors are presented. PMID:28220057

  17. Receptor-based 3D-QSAR in Drug Design: Methods and Applications in Kinase Studies.

    PubMed

    Fang, Cheng; Xiao, Zhiyan

    2016-01-01

    Receptor-based 3D-QSAR strategy represents a superior integration of structure-based drug design (SBDD) and three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis. It combines the accurate prediction of ligand poses by the SBDD approach with the good predictability and interpretability of statistical models derived from the 3D-QSAR approach. Extensive efforts have been devoted to the development of receptor-based 3D-QSAR methods and two alternative approaches have been exploited. One associates with computing the binding interactions between a receptor and a ligand to generate structure-based descriptors for QSAR analyses. The other concerns the application of various docking protocols to generate optimal ligand poses so as to provide reliable molecular alignments for the conventional 3D-QSAR operations. This review highlights new concepts and methodologies recently developed in the field of receptorbased 3D-QSAR, and in particular, covers its application in kinase studies.

  18. 3D Face Recognition Based on Multiple Keypoint Descriptors and Sparse Representation

    PubMed Central

    Zhang, Lin; Ding, Zhixuan; Li, Hongyu; Shen, Ying; Lu, Jianwei

    2014-01-01

    Recent years have witnessed a growing interest in developing methods for 3D face recognition. However, 3D scans often suffer from the problems of missing parts, large facial expressions, and occlusions. To be useful in real-world applications, a 3D face recognition approach should be able to handle these challenges. In this paper, we propose a novel general approach to deal with the 3D face recognition problem by making use of multiple keypoint descriptors (MKD) and the sparse representation-based classification (SRC). We call the proposed method 3DMKDSRC for short. Specifically, with 3DMKDSRC, each 3D face scan is represented as a set of descriptor vectors extracted from keypoints by meshSIFT. Descriptor vectors of gallery samples form the gallery dictionary. Given a probe 3D face scan, its descriptors are extracted at first and then its identity can be determined by using a multitask SRC. The proposed 3DMKDSRC approach does not require the pre-alignment between two face scans and is quite robust to the problems of missing data, occlusions and expressions. Its superiority over the other leading 3D face recognition schemes has been corroborated by extensive experiments conducted on three benchmark databases, Bosphorus, GavabDB, and FRGC2.0. The Matlab source code for 3DMKDSRC and the related evaluation results are publicly available at http://sse.tongji.edu.cn/linzhang/3dmkdsrcface/3dmkdsrc.htm. PMID:24940876

  19. Electro-holography display using computer generated hologram of 3D objects based on projection spectra

    NASA Astrophysics Data System (ADS)

    Huang, Sujuan; Wang, Duocheng; He, Chao

    2012-11-01

    A new method of synthesizing computer-generated hologram of three-dimensional (3D) objects is proposed from their projection images. A series of projection images of 3D objects are recorded with one-dimensional azimuth scanning. According to the principles of paraboloid of revolution in 3D Fourier space and 3D central slice theorem, spectra information of 3D objects can be gathered from their projection images. Considering quantization error of horizontal and vertical directions, the spectrum information from each projection image is efficiently extracted in double circle and four circles shape, to enhance the utilization of projection spectra. Then spectra information of 3D objects from all projection images is encoded into computer-generated hologram based on Fourier transform using conjugate-symmetric extension. The hologram includes 3D information of objects. Experimental results for numerical reconstruction of the CGH at different distance validate the proposed methods and show its good performance. Electro-holographic reconstruction can be realized by using an electronic addressing reflective liquid-crystal display (LCD) spatial light modulator. The CGH from the computer is loaded onto the LCD. By illuminating a reference light from a laser source to the LCD, the amplitude and phase information included in the CGH will be reconstructed due to the diffraction of the light modulated by the LCD.

  20. 3D face recognition based on multiple keypoint descriptors and sparse representation.

    PubMed

    Zhang, Lin; Ding, Zhixuan; Li, Hongyu; Shen, Ying; Lu, Jianwei

    2014-01-01

    Recent years have witnessed a growing interest in developing methods for 3D face recognition. However, 3D scans often suffer from the problems of missing parts, large facial expressions, and occlusions. To be useful in real-world applications, a 3D face recognition approach should be able to handle these challenges. In this paper, we propose a novel general approach to deal with the 3D face recognition problem by making use of multiple keypoint descriptors (MKD) and the sparse representation-based classification (SRC). We call the proposed method 3DMKDSRC for short. Specifically, with 3DMKDSRC, each 3D face scan is represented as a set of descriptor vectors extracted from keypoints by meshSIFT. Descriptor vectors of gallery samples form the gallery dictionary. Given a probe 3D face scan, its descriptors are extracted at first and then its identity can be determined by using a multitask SRC. The proposed 3DMKDSRC approach does not require the pre-alignment between two face scans and is quite robust to the problems of missing data, occlusions and expressions. Its superiority over the other leading 3D face recognition schemes has been corroborated by extensive experiments conducted on three benchmark databases, Bosphorus, GavabDB, and FRGC2.0. The Matlab source code for 3DMKDSRC and the related evaluation results are publicly available at http://sse.tongji.edu.cn/linzhang/3dmkdsrcface/3dmkdsrc.htm.

  1. Wavelet-based analysis of blood pressure dynamics in rats

    NASA Astrophysics Data System (ADS)

    Pavlov, A. N.; Anisimov, A. A.; Semyachkina-Glushkovskaya, O. V.; Berdnikova, V. A.; Kuznecova, A. S.; Matasova, E. G.

    2009-02-01

    Using a wavelet-based approach, we study stress-induced reactions in the blood pressure dynamics in rats. Further, we consider how the level of the nitric oxide (NO) influences the heart rate variability. Clear distinctions for male and female rats are reported.

  2. Enhancing Hyperspectral Data Throughput Utilizing Wavelet-Based Fingerprints

    SciTech Connect

    I. W. Ginsberg

    1999-09-01

    Multiresolutional decompositions known as spectral fingerprints are often used to extract spectral features from multispectral/hyperspectral data. In this study, the authors investigate the use of wavelet-based algorithms for generating spectral fingerprints. The wavelet-based algorithms are compared to the currently used method, traditional convolution with first-derivative Gaussian filters. The comparison analyses consists of two parts: (a) the computational expense of the new method is compared with the computational costs of the current method and (b) the outputs of the wavelet-based methods are compared with those of the current method to determine any practical differences in the resulting spectral fingerprints. The results show that the wavelet-based algorithms can greatly reduce the computational expense of generating spectral fingerprints, while practically no differences exist in the resulting fingerprints. The analysis is conducted on a database of hyperspectral signatures, namely, Hyperspectral Digital Image Collection Experiment (HYDICE) signatures. The reduction in computational expense is by a factor of about 30, and the average Euclidean distance between resulting fingerprints is on the order of 0.02.

  3. 3D model-based catheter tracking for motion compensation in EP procedures

    NASA Astrophysics Data System (ADS)

    Brost, Alexander; Liao, Rui; Hornegger, Joachim; Strobel, Norbert

    2010-02-01

    Atrial fibrillation is the most common sustained heart arrhythmia and a leading cause of stroke. Its treatment by radio-frequency catheter ablation, performed using fluoroscopic image guidance, is gaining increasingly more importance. Two-dimensional fluoroscopic navigation can take advantage of overlay images derived from pre-operative 3-D data to add anatomical details otherwise not visible under X-ray. Unfortunately, respiratory motion may impair the utility of these static overlay images for catheter navigation. We developed an approach for image-based 3-D motion compensation as a solution to this problem. A bi-plane C-arm system is used to take X-ray images of a special circumferential mapping catheter from two directions. In the first step of the method, a 3-D model of the device is reconstructed. Three-dimensional respiratory motion at the site of ablation is then estimated by tracking the reconstructed catheter model in 3-D. This step involves bi-plane fluoroscopy and 2-D/3-D registration. Phantom data and clinical data were used to assess our model-based catheter tracking method. Experiments involving a moving heart phantom yielded an average 2-D tracking error of 1.4 mm and an average 3-D tracking error of 1.1 mm. Our evaluation of clinical data sets comprised 469 bi-plane fluoroscopy frames (938 monoplane fluoroscopy frames). We observed an average 2-D tracking error of 1.0 mm +/- 0.4 mm and an average 3-D tracking error of 0.8 mm +/- 0.5 mm. These results demonstrate that model-based motion-compensation based on 2-D/3-D registration is both feasible and accurate.

  4. Graphene Oxide-Based Electrode Inks for 3D-Printed Lithium-Ion Batteries.

    PubMed

    Fu, Kun; Wang, Yibo; Yan, Chaoyi; Yao, Yonggang; Chen, Yanan; Dai, Jiaqi; Lacey, Steven; Wang, Yanbin; Wan, Jiayu; Li, Tian; Wang, Zhengyang; Xu, Yue; Hu, Liangbing

    2016-04-06

    All-component 3D-printed lithium-ion batteries are fabricated by printing graphene-oxide-based composite inks and solid-state gel polymer electrolyte. An entirely 3D-printed full cell features a high electrode mass loading of 18 mg cm(-2) , which is normalized to the overall area of the battery. This all-component printing can be extended to the fabrication of multidimensional/multiscale complex-structures of more energy-storage devices.

  5. Towards real-time change detection in videos based on existing 3D models

    NASA Astrophysics Data System (ADS)

    Ruf, Boitumelo; Schuchert, Tobias

    2016-10-01

    Image based change detection is of great importance for security applications, such as surveillance and reconnaissance, in order to find new, modified or removed objects. Such change detection can generally be performed by co-registration and comparison of two or more images. However, existing 3d objects, such as buildings, may lead to parallax artifacts in case of inaccurate or missing 3d information, which may distort the results in the image comparison process, especially when the images are acquired from aerial platforms like small unmanned aerial vehicles (UAVs). Furthermore, considering only intensity information may lead to failures in detection of changes in the 3d structure of objects. To overcome this problem, we present an approach that uses Structure-from-Motion (SfM) to compute depth information, with which a 3d change detection can be performed against an existing 3d model. Our approach is capable of the change detection in real-time. We use the input frames with the corresponding camera poses to compute dense depth maps by an image-based depth estimation algorithm. Additionally we synthesize a second set of depth maps, by rendering the existing 3d model from the same camera poses as those of the image-based depth map. The actual change detection is performed by comparing the two sets of depth maps with each other. Our method is evaluated on synthetic test data with corresponding ground truth as well as on real image test data.

  6. Demonstration of three gorges archaeological relics based on 3D-visualization technology

    NASA Astrophysics Data System (ADS)

    Xu, Wenli

    2015-12-01

    This paper mainly focuses on the digital demonstration of three gorges archeological relics to exhibit the achievements of the protective measures. A novel and effective method based on 3D-visualization technology, which includes large-scaled landscape reconstruction, virtual studio, and virtual panoramic roaming, etc, is proposed to create a digitized interactive demonstration system. The method contains three stages: pre-processing, 3D modeling and integration. Firstly, abundant archaeological information is classified according to its history and geographical information. Secondly, build up a 3D-model library with the technology of digital images processing and 3D modeling. Thirdly, use virtual reality technology to display the archaeological scenes and cultural relics vividly and realistically. The present work promotes the application of virtual reality to digital projects and enriches the content of digital archaeology.

  7. 3D web based learning of medical equipment employed in intensive care units.

    PubMed

    Cetin, Aydın

    2012-02-01

    In this paper, both synchronous and asynchronous web based learning of 3D medical equipment models used in hospital intensive care unit have been described over the moodle course management system. 3D medical equipment models were designed with 3ds Max 2008, then converted to ASE format and added interactivity displayed with Viewpoint-Enliven. 3D models embedded in a web page in html format with dynamic interactivity-rotating, panning and zooming by dragging a mouse over images-and descriptive information is embedded to 3D model by using xml format. A pilot test course having 15 h was applied to technicians who is responsible for intensive care unit at Medical Devices Repairing and Maintenance Center (TABOM) of Turkish High Specialized Hospital.

  8. 3D printing of mineral-polymer bone substitutes based on sodium alginate and calcium phosphate.

    PubMed

    Egorov, Aleksey A; Fedotov, Alexander Yu; Mironov, Anton V; Komlev, Vladimir S; Popov, Vladimir K; Zobkov, Yury V

    2016-01-01

    We demonstrate a relatively simple route for three-dimensional (3D) printing of complex-shaped biocompatible structures based on sodium alginate and calcium phosphate (CP) for bone tissue engineering. The fabrication of 3D composite structures was performed through the synthesis of inorganic particles within a biopolymer macromolecular network during 3D printing process. The formation of a new CP phase was studied through X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Both the phase composition and the diameter of the CP particles depend on the concentration of a liquid component (i.e., the "ink"). The 3D printed structures were fabricated and found to have large interconnected porous systems (mean diameter ≈800 μm) and were found to possess compressive strengths from 0.45 to 1.0 MPa. This new approach can be effectively applied for fabrication of biocompatible scaffolds for bone tissue engineering constructions.

  9. 3D point cloud registration based on the assistant camera and Harris-SIFT

    NASA Astrophysics Data System (ADS)

    Zhang, Yue; Yu, HongYang

    2016-07-01

    3D(Three-Dimensional) point cloud registration technology is the hot topic in the field of 3D reconstruction, but most of the registration method is not real-time and ineffective. This paper proposes a point cloud registration method of 3D reconstruction based on Harris-SIFT and assistant camera. The assistant camera is used to pinpoint mobile 3D reconstruction device, The feature points of images are detected by using Harris operator, the main orientation for each feature point is calculated, and lastly, the feature point descriptors are generated after rotating the coordinates of the descriptors relative to the feature points' main orientations. Experimental results of demonstrate the effectiveness of the proposed method.

  10. 3D printing of mineral–polymer bone substitutes based on sodium alginate and calcium phosphate

    PubMed Central

    Egorov, Aleksey A; Fedotov, Alexander Yu; Mironov, Anton V; Popov, Vladimir K; Zobkov, Yury V

    2016-01-01

    We demonstrate a relatively simple route for three-dimensional (3D) printing of complex-shaped biocompatible structures based on sodium alginate and calcium phosphate (CP) for bone tissue engineering. The fabrication of 3D composite structures was performed through the synthesis of inorganic particles within a biopolymer macromolecular network during 3D printing process. The formation of a new CP phase was studied through X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Both the phase composition and the diameter of the CP particles depend on the concentration of a liquid component (i.e., the “ink”). The 3D printed structures were fabricated and found to have large interconnected porous systems (mean diameter ≈800 μm) and were found to possess compressive strengths from 0.45 to 1.0 MPa. This new approach can be effectively applied for fabrication of biocompatible scaffolds for bone tissue engineering constructions. PMID:28144529

  11. Correspondenceless 3D-2D registration based on expectation conditional maximization

    NASA Astrophysics Data System (ADS)

    Kang, X.; Taylor, R. H.; Armand, M.; Otake, Y.; Yau, W. P.; Cheung, P. Y. S.; Hu, Y.

    2011-03-01

    3D-2D registration is a fundamental task in image guided interventions. Due to the physics of the X-ray imaging, however, traditional point based methods meet new challenges, where the local point features are indistinguishable, creating difficulties in establishing correspondence between 2D image feature points and 3D model points. In this paper, we propose a novel method to accomplish 3D-2D registration without known correspondences. Given a set of 3D and 2D unmatched points, this is achieved by introducing correspondence probabilities that we model as a mixture model. By casting it into the expectation conditional maximization framework, without establishing one-to-one point correspondences, we can iteratively refine the registration parameters. The method has been tested on 100 real X-ray images. The experiments showed that the proposed method accurately estimated the rotations (< 1°) and in-plane (X-Y plane) translations (< 1 mm).

  12. A 3D terrain reconstruction method of stereo vision based quadruped robot navigation system

    NASA Astrophysics Data System (ADS)

    Ge, Zhuo; Zhu, Ying; Liang, Guanhao

    2017-01-01

    To provide 3D environment information for the quadruped robot autonomous navigation system during walking through rough terrain, based on the stereo vision, a novel 3D terrain reconstruction method is presented. In order to solve the problem that images collected by stereo sensors have large regions with similar grayscale and the problem that image matching is poor at real-time performance, watershed algorithm and fuzzy c-means clustering algorithm are combined for contour extraction. Aiming at the problem of error matching, duel constraint with region matching and pixel matching is established for matching optimization. Using the stereo matching edge pixel pairs, the 3D coordinate algorithm is estimated according to the binocular stereo vision imaging model. Experimental results show that the proposed method can yield high stereo matching ratio and reconstruct 3D scene quickly and efficiently.

  13. Wavelet Algorithm for Feature Identification and Image Analysis

    SciTech Connect

    Moss, William C.; Haase, Sebastian; Sedat, John W.

    2005-10-01

    WVL are a set of python scripts based on the algorithm described in "A novel 3D wavelet-based filter for visualizing features in noisy biological data, " W. C. Moss et al., J. Microsc. 219, 43-49 (2005)

  14. Leg Motion Classification with Artificial Neural Networks Using Wavelet-Based Features of Gyroscope Signals

    PubMed Central

    Ayrulu-Erdem, Birsel; Barshan, Billur

    2011-01-01

    We extract the informative features of gyroscope signals using the discrete wavelet transform (DWT) decomposition and provide them as input to multi-layer feed-forward artificial neural networks (ANNs) for leg motion classification. Since the DWT is based on correlating the analyzed signal with a prototype wavelet function, selection of the wavelet type can influence the performance of wavelet-based applications significantly. We also investigate the effect of selecting different wavelet families on classification accuracy and ANN complexity and provide a comparison between them. The maximum classification accuracy of 97.7% is achieved with the Daubechies wavelet of order 16 and the reverse bi-orthogonal (RBO) wavelet of order 3.1, both with similar ANN complexity. However, the RBO 3.1 wavelet is preferable because of its lower computational complexity in the DWT decomposition and reconstruction. PMID:22319378

  15. Leg motion classification with artificial neural networks using wavelet-based features of gyroscope signals.

    PubMed

    Ayrulu-Erdem, Birsel; Barshan, Billur

    2011-01-01

    We extract the informative features of gyroscope signals using the discrete wavelet transform (DWT) decomposition and provide them as input to multi-layer feed-forward artificial neural networks (ANNs) for leg motion classification. Since the DWT is based on correlating the analyzed signal with a prototype wavelet function, selection of the wavelet type can influence the performance of wavelet-based applications significantly. We also investigate the effect of selecting different wavelet families on classification accuracy and ANN complexity and provide a comparison between them. The maximum classification accuracy of 97.7% is achieved with the Daubechies wavelet of order 16 and the reverse bi-orthogonal (RBO) wavelet of order 3.1, both with similar ANN complexity. However, the RBO 3.1 wavelet is preferable because of its lower computational complexity in the DWT decomposition and reconstruction.

  16. Volumetric CT-based segmentation of NSCLC using 3D-Slicer

    PubMed Central

    Velazquez, Emmanuel Rios; Parmar, Chintan; Jermoumi, Mohammed; Mak, Raymond H.; van Baardwijk, Angela; Fennessy, Fiona M.; Lewis, John H.; De Ruysscher, Dirk; Kikinis, Ron; Lambin, Philippe; Aerts, Hugo J. W. L.

    2013-01-01

    Accurate volumetric assessment in non-small cell lung cancer (NSCLC) is critical for adequately informing treatments. In this study we assessed the clinical relevance of a semiautomatic computed tomography (CT)-based segmentation method using the competitive region-growing based algorithm, implemented in the free and public available 3D-Slicer software platform. We compared the 3D-Slicer segmented volumes by three independent observers, who segmented the primary tumour of 20 NSCLC patients twice, to manual slice-by-slice delineations of five physicians. Furthermore, we compared all tumour contours to the macroscopic diameter of the tumour in pathology, considered as the “gold standard”. The 3D-Slicer segmented volumes demonstrated high agreement (overlap fractions > 0.90), lower volume variability (p = 0.0003) and smaller uncertainty areas (p = 0.0002), compared to manual slice-by-slice delineations. Furthermore, 3D-Slicer segmentations showed a strong correlation to pathology (r = 0.89, 95%CI, 0.81–0.94). Our results show that semiautomatic 3D-Slicer segmentations can be used for accurate contouring and are more stable than manual delineations. Therefore, 3D-Slicer can be employed as a starting point for treatment decisions or for high-throughput data mining research, such as Radiomics, where manual delineating often represent a time-consuming bottleneck. PMID:24346241

  17. Robot navigation in cluttered 3-D environments using preference-based fuzzy behaviors.

    PubMed

    Shi, Dongqing; Collins, Emmanuel G; Dunlap, Damion

    2007-12-01

    Autonomous navigation systems for mobile robots have been successfully deployed for a wide range of planar ground-based tasks. However, very few counterparts of previous planar navigation systems were developed for 3-D motion, which is needed for both unmanned aerial and underwater vehicles. A novel fuzzy behavioral scheme for navigating an unmanned helicopter in cluttered 3-D spaces is developed. The 3-D navigation problem is decomposed into several identical 2-D navigation subproblems, each of which is solved by using preference-based fuzzy behaviors. Due to the shortcomings of vector summation during the fusion of the 2-D subproblems, instead of directly outputting steering subdirections by their own defuzzification processes, the intermediate preferences of the subproblems are fused to create a 3-D solution region, representing degrees of preference for the robot movement. A new defuzzification algorithm that steers the robot by finding the centroid of a 3-D convex region of maximum volume in the 3-D solution region is developed. A fuzzy speed-control system is also developed to ensure efficient and safe navigation. Substantial simulations have been carried out to demonstrate that the proposed algorithm can smoothly and effectively guide an unmanned helicopter through unknown and cluttered urban and forest environments.

  18. Sensitivity Analysis of the Scattering-Based SARBM3D Despeckling Algorithm

    PubMed Central

    Di Simone, Alessio

    2016-01-01

    Synthetic Aperture Radar (SAR) imagery greatly suffers from multiplicative speckle noise, typical of coherent image acquisition sensors, such as SAR systems. Therefore, a proper and accurate despeckling preprocessing step is almost mandatory to aid the interpretation and processing of SAR data by human users and computer algorithms, respectively. Very recently, a scattering-oriented version of the popular SAR Block-Matching 3D (SARBM3D) despeckling filter, named Scattering-Based (SB)-SARBM3D, was proposed. The new filter is based on the a priori knowledge of the local topography of the scene. In this paper, an experimental sensitivity analysis of the above-mentioned despeckling algorithm is carried out, and the main results are shown and discussed. In particular, the role of both electromagnetic and geometrical parameters of the surface and the impact of its scattering behavior are investigated. Furthermore, a comprehensive sensitivity analysis of the SB-SARBM3D filter against the Digital Elevation Model (DEM) resolution and the SAR image-DEM coregistration step is also provided. The sensitivity analysis shows a significant robustness of the algorithm against most of the surface parameters, while the DEM resolution plays a key role in the despeckling process. Furthermore, the SB-SARBM3D algorithm outperforms the original SARBM3D in the presence of the most realistic scattering behaviors of the surface. An actual scenario is also presented to assess the DEM role in real-life conditions. PMID:27347971

  19. Volumetric CT-based segmentation of NSCLC using 3D-Slicer

    NASA Astrophysics Data System (ADS)

    Velazquez, Emmanuel Rios; Parmar, Chintan; Jermoumi, Mohammed; Mak, Raymond H.; van Baardwijk, Angela; Fennessy, Fiona M.; Lewis, John H.; de Ruysscher, Dirk; Kikinis, Ron; Lambin, Philippe; Aerts, Hugo J. W. L.

    2013-12-01

    Accurate volumetric assessment in non-small cell lung cancer (NSCLC) is critical for adequately informing treatments. In this study we assessed the clinical relevance of a semiautomatic computed tomography (CT)-based segmentation method using the competitive region-growing based algorithm, implemented in the free and public available 3D-Slicer software platform. We compared the 3D-Slicer segmented volumes by three independent observers, who segmented the primary tumour of 20 NSCLC patients twice, to manual slice-by-slice delineations of five physicians. Furthermore, we compared all tumour contours to the macroscopic diameter of the tumour in pathology, considered as the ``gold standard''. The 3D-Slicer segmented volumes demonstrated high agreement (overlap fractions > 0.90), lower volume variability (p = 0.0003) and smaller uncertainty areas (p = 0.0002), compared to manual slice-by-slice delineations. Furthermore, 3D-Slicer segmentations showed a strong correlation to pathology (r = 0.89, 95%CI, 0.81-0.94). Our results show that semiautomatic 3D-Slicer segmentations can be used for accurate contouring and are more stable than manual delineations. Therefore, 3D-Slicer can be employed as a starting point for treatment decisions or for high-throughput data mining research, such as Radiomics, where manual delineating often represent a time-consuming bottleneck.

  20. Sensitivity Analysis of the Scattering-Based SARBM3D Despeckling Algorithm.

    PubMed

    Di Simone, Alessio

    2016-06-25

    Synthetic Aperture Radar (SAR) imagery greatly suffers from multiplicative speckle noise, typical of coherent image acquisition sensors, such as SAR systems. Therefore, a proper and accurate despeckling preprocessing step is almost mandatory to aid the interpretation and processing of SAR data by human users and computer algorithms, respectively. Very recently, a scattering-oriented version of the popular SAR Block-Matching 3D (SARBM3D) despeckling filter, named Scattering-Based (SB)-SARBM3D, was proposed. The new filter is based on the a priori knowledge of the local topography of the scene. In this paper, an experimental sensitivity analysis of the above-mentioned despeckling algorithm is carried out, and the main results are shown and discussed. In particular, the role of both electromagnetic and geometrical parameters of the surface and the impact of its scattering behavior are investigated. Furthermore, a comprehensive sensitivity analysis of the SB-SARBM3D filter against the Digital Elevation Model (DEM) resolution and the SAR image-DEM coregistration step is also provided. The sensitivity analysis shows a significant robustness of the algorithm against most of the surface parameters, while the DEM resolution plays a key role in the despeckling process. Furthermore, the SB-SARBM3D algorithm outperforms the original SARBM3D in the presence of the most realistic scattering behaviors of the surface. An actual scenario is also presented to assess the DEM role in real-life conditions.

  1. 3D surface reconstruction based on image stitching from gastric endoscopic video sequence

    NASA Astrophysics Data System (ADS)

    Duan, Mengyao; Xu, Rong; Ohya, Jun

    2013-09-01

    This paper proposes a method for reconstructing 3D detailed structures of internal organs such as gastric wall from endoscopic video sequences. The proposed method consists of the four major steps: Feature-point-based 3D reconstruction, 3D point cloud stitching, dense point cloud creation and Poisson surface reconstruction. Before the first step, we partition one video sequence into groups, where each group consists of two successive frames (image pairs), and each pair in each group contains one overlapping part, which is used as a stitching region. Fist, the 3D point cloud of each group is reconstructed by utilizing structure from motion (SFM). Secondly, a scheme based on SIFT features registers and stitches the obtained 3D point clouds, by estimating the transformation matrix of the overlapping part between different groups with high accuracy and efficiency. Thirdly, we select the most robust SIFT feature points as the seed points, and then obtain the dense point cloud from sparse point cloud via a depth testing method presented by Furukawa. Finally, by utilizing Poisson surface reconstruction, polygonal patches for the internal organs are obtained. Experimental results demonstrate that the proposed method achieves a high accuracy and efficiency for 3D reconstruction of gastric surface from an endoscopic video sequence.

  2. Fast wavelet based sparse approximate inverse preconditioner

    SciTech Connect

    Wan, W.L.

    1996-12-31

    Incomplete LU factorization is a robust preconditioner for both general and PDE problems but unfortunately not easy to parallelize. Recent study of Huckle and Grote and Chow and Saad showed that sparse approximate inverse could be a potential alternative while readily parallelizable. However, for special class of matrix A that comes from elliptic PDE problems, their preconditioners are not optimal in the sense that independent of mesh size. A reason may be that no good sparse approximate inverse exists for the dense inverse matrix. Our observation is that for this kind of matrices, its inverse entries typically have piecewise smooth changes. We can take advantage of this fact and use wavelet compression techniques to construct a better sparse approximate inverse preconditioner. We shall show numerically that our approach is effective for this kind of matrices.

  3. Efficient view based 3-D object retrieval using Hidden Markov Model

    NASA Astrophysics Data System (ADS)

    Jain, Yogendra Kumar; Singh, Roshan Kumar

    2013-12-01

    Recent research effort has been dedicated to view based 3-D object retrieval, because of highly discriminative property of 3-D object and has multi view representation. The state-of-art method is highly depending on their own camera array setting for capturing views of 3-D object and use complex Zernike descriptor, HAC for representative view selection which limit their practical application and make it inefficient for retrieval. Therefore, an efficient and effective algorithm is required for 3-D Object Retrieval. In order to move toward a general framework for efficient 3-D object retrieval which is independent of camera array setting and avoidance of representative view selection, we propose an Efficient View Based 3-D Object Retrieval (EVBOR) method using Hidden Markov Model (HMM). In this framework, each object is represented by independent set of view, which means views are captured from any direction without any camera array restriction. In this, views are clustered (including query view) to generate the view cluster, which is then used to build the query model with HMM. In our proposed method, HMM is used in twofold: in the training (i.e. HMM estimate) and in the retrieval (i.e. HMM decode). The query model is trained by using these view clusters. The EVBOR query model is worked on the basis of query model combining with HMM. The proposed approach remove statically camera array setting for view capturing and can be apply for any 3-D object database to retrieve 3-D object efficiently and effectively. Experimental results demonstrate that the proposed scheme has shown better performance than existing methods. [Figure not available: see fulltext.

  4. Wavelet decomposition-based efficient face liveness detection

    NASA Astrophysics Data System (ADS)

    Moniruzzaman, Md.; Alam, Mohammad S.

    2016-04-01

    Existing face recognition systems are susceptible to spoofing attacks. So, Face liveness detection is a pivotal part for reliable face recognition, which has recently acknowledged vast attention. In this paper we propose a wavelet decomposition based face liveness recognition system using an energy calculation technique. Live faces contain high energy components compared to fake or printed image. In this paper, we calculate energy components of live face as well as fake face using discrete wavelet decomposition method. We analyze percentage of energy at different levels as well as for different wavelet basis function. We also analyze percentage of energy at different RGB bands and efficient face liveness detection method has been proposed. Discrete wavelet representation has been used to calculate decomposed energy components. Moreover, it provides differentiation of several spatial orientations as well as average and detailed information which are missing in the fake faces. This technique provides excellent discrimination capability when compared to the previously reported works based on the discrete Fourier transform and n-dimensional Fourier transform operations. To verify the proposed approach, we tested the performance using various face antispoofing datasets such as university of south Alabama (UFAD), and MSU face antispoofing dataset which incorporates different types of attacks. The test results obtained using the proposed technique shows better performance compared to existing techniques.

  5. A Wavelet-Based Approach to Fall Detection

    PubMed Central

    Palmerini, Luca; Bagalà, Fabio; Zanetti, Andrea; Klenk, Jochen; Becker, Clemens; Cappello, Angelo

    2015-01-01

    Falls among older people are a widely documented public health problem. Automatic fall detection has recently gained huge importance because it could allow for the immediate communication of falls to medical assistance. The aim of this work is to present a novel wavelet-based approach to fall detection, focusing on the impact phase and using a dataset of real-world falls. Since recorded falls result in a non-stationary signal, a wavelet transform was chosen to examine fall patterns. The idea is to consider the average fall pattern as the “prototype fall”.In order to detect falls, every acceleration signal can be compared to this prototype through wavelet analysis. The similarity of the recorded signal with the prototype fall is a feature that can be used in order to determine the difference between falls and daily activities. The discriminative ability of this feature is evaluated on real-world data. It outperforms other features that are commonly used in fall detection studies, with an Area Under the Curve of 0.918. This result suggests that the proposed wavelet-based feature is promising and future studies could use this feature (in combination with others considering different fall phases) in order to improve the performance of fall detection algorithms. PMID:26007719

  6. A universal approach for automatic organ segmentations on 3D CT images based on organ localization and 3D GrabCut

    NASA Astrophysics Data System (ADS)

    Zhou, Xiangrong; Ito, Takaaki; Zhou, Xinxin; Chen, Huayue; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Fujita, Hiroshi

    2014-03-01

    This paper describes a universal approach to automatic segmentation of different internal organ and tissue regions in three-dimensional (3D) computerized tomography (CT) scans. The proposed approach combines object localization, a probabilistic atlas, and 3D GrabCut techniques to achieve automatic and quick segmentation. The proposed method first detects a tight 3D bounding box that contains the target organ region in CT images and then estimates the prior of each pixel inside the bounding box belonging to the organ region or background based on a dynamically generated probabilistic atlas. Finally, the target organ region is separated from the background by using an improved 3D GrabCut algorithm. A machine-learning method is used to train a detector to localize the 3D bounding box of the target organ using template matching on a selected feature space. A content-based image retrieval method is used for online generation of a patient-specific probabilistic atlas for the target organ based on a database. A 3D GrabCut algorithm is used for final organ segmentation by iteratively estimating the CT number distributions of the target organ and backgrounds using a graph-cuts algorithm. We applied this approach to localize and segment twelve major organ and tissue regions independently based on a database that includes 1300 torso CT scans. In our experiments, we randomly selected numerous CT scans and manually input nine principal types of inner organ regions for performance evaluation. Preliminary results showed the feasibility and efficiency of the proposed approach for addressing automatic organ segmentation issues on CT images.

  7. On the spline-based wavelet differentiation matrix

    NASA Technical Reports Server (NTRS)

    Jameson, Leland

    1993-01-01

    The differentiation matrix for a spline-based wavelet basis is constructed. Given an n-th order spline basis it is proved that the differentiation matrix is accurate of order 2n + 2 when periodic boundary conditions are assumed. This high accuracy, or superconvergence, is lost when the boundary conditions are no longer periodic. Furthermore, it is shown that spline-based bases generate a class of compact finite difference schemes.

  8. 3D printed microfluidic circuitry via multijet-based additive manufacturing†

    PubMed Central

    Sochol, R. D.; Sweet, E.; Glick, C. C.; Venkatesh, S.; Avetisyan, A.; Ekman, K. F.; Raulinaitis, A.; Tsai, A.; Wienkers, A.; Korner, K.; Hanson, K.; Long, A.; Hightower, B. J.; Slatton, G.; Burnett, D. C.; Massey, T. L.; Iwai, K.; Lee, L. P.; Pister, K. S. J.; Lin, L.

    2016-01-01

    The miniaturization of integrated fluidic processors affords extensive benefits for chemical and biological fields, yet traditional, monolithic methods of microfabrication present numerous obstacles for the scaling of fluidic operators. Recently, researchers have investigated the use of additive manufacturing or “three-dimensional (3D) printing” technologies – predominantly stereolithography – as a promising alternative for the construction of submillimeter-scale fluidic components. One challenge, however, is that current stereolithography methods lack the ability to simultaneously print sacrificial support materials, which limits the geometric versatility of such approaches. In this work, we investigate the use of multijet modelling (alternatively, polyjet printing) – a layer-by-layer, multi-material inkjetting process – for 3D printing geometrically complex, yet functionally advantageous fluidic components comprised of both static and dynamic physical elements. We examine a fundamental class of 3D printed microfluidic operators, including fluidic capacitors, fluidic diodes, and fluidic transistors. In addition, we evaluate the potential to advance on-chip automation of integrated fluidic systems via geometric modification of component parameters. Theoretical and experimental results for 3D fluidic capacitors demonstrated that transitioning from planar to non-planar diaphragm architectures improved component performance. Flow rectification experiments for 3D printed fluidic diodes revealed a diodicity of 80.6 ± 1.8. Geometry-based gain enhancement for 3D printed fluidic transistors yielded pressure gain of 3.01 ± 0.78. Consistent with additional additive manufacturing methodologies, the use of digitally-transferrable 3D models of fluidic components combined with commercially-available 3D printers could extend the fluidic routing capabilities presented here to researchers in fields beyond the core engineering community. PMID:26725379

  9. 3D printed microfluidic circuitry via multijet-based additive manufacturing.

    PubMed

    Sochol, R D; Sweet, E; Glick, C C; Venkatesh, S; Avetisyan, A; Ekman, K F; Raulinaitis, A; Tsai, A; Wienkers, A; Korner, K; Hanson, K; Long, A; Hightower, B J; Slatton, G; Burnett, D C; Massey, T L; Iwai, K; Lee, L P; Pister, K S J; Lin, L

    2016-02-21

    The miniaturization of integrated fluidic processors affords extensive benefits for chemical and biological fields, yet traditional, monolithic methods of microfabrication present numerous obstacles for the scaling of fluidic operators. Recently, researchers have investigated the use of additive manufacturing or "three-dimensional (3D) printing" technologies - predominantly stereolithography - as a promising alternative for the construction of submillimeter-scale fluidic components. One challenge, however, is that current stereolithography methods lack the ability to simultaneously print sacrificial support materials, which limits the geometric versatility of such approaches. In this work, we investigate the use of multijet modelling (alternatively, polyjet printing) - a layer-by-layer, multi-material inkjetting process - for 3D printing geometrically complex, yet functionally advantageous fluidic components comprised of both static and dynamic physical elements. We examine a fundamental class of 3D printed microfluidic operators, including fluidic capacitors, fluidic diodes, and fluidic transistors. In addition, we evaluate the potential to advance on-chip automation of integrated fluidic systems via geometric modification of component parameters. Theoretical and experimental results for 3D fluidic capacitors demonstrated that transitioning from planar to non-planar diaphragm architectures improved component performance. Flow rectification experiments for 3D printed fluidic diodes revealed a diodicity of 80.6 ± 1.8. Geometry-based gain enhancement for 3D printed fluidic transistors yielded pressure gain of 3.01 ± 0.78. Consistent with additional additive manufacturing methodologies, the use of digitally-transferrable 3D models of fluidic components combined with commercially-available 3D printers could extend the fluidic routing capabilities presented here to researchers in fields beyond the core engineering community.

  10. 3D digitization methods based on laser excitation and active triangulation: a comparison

    NASA Astrophysics Data System (ADS)

    Aubreton, Olivier; Mériaudeau, Fabrice; Truchetet, Frédéric

    2016-04-01

    3D reconstruction of surfaces is an important topic in computer vision and corresponds to a large field of applications: industrial inspection, reverse engineering, object recognition, biometry, archeology… Because of the large varieties of applications, one can find in the literature a lot of approaches which can be classified into two families: passive and active [1]. Certainly because of their reliability, active approaches, using imaging system with an additional controlled light source, seem to be the most commonly used in the industrial field. In this domain, the 3D digitization approach based on active 3D triangulation has had important developments during the last ten years [2] and seems to be mature today if considering the important number of systems proposed by manufacturers. Unfortunately, the performances of active 3D scanners depend on the optical properties of the surface to digitize. As an example, on Fig 1.a, a 3D shape with a diffuse surface has been digitized with Comet V scanner (Steinbichler). The 3D reconstruction is presented on Fig 1.b. The same experiment was carried out on a similar object (same shape) but presenting a specular surface (Fig 1.c and Fig 1.d) ; it can clearly be observed, that the specularity influences of the performance of the digitization.

  11. Front and rear projection autostereoscopic 3D displays based on lenticular sheets

    NASA Astrophysics Data System (ADS)

    Wang, Qiong-Hua; Zang, Shang-Fei; Qi, Lin

    2015-03-01

    A front projection autostereoscopic display is proposed. The display is composed of eight projectors and a 3D-imageguided screen which having a lenticular sheet and a retro-reflective diffusion screen. Based on the optical multiplexing and de-multiplexing, the optical functions of the 3D-image-guided screen are parallax image interlacing and viewseparating, which is capable of reconstructing 3D images without quality degradation from the front direction. The operating principle, optical design calculation equations and correction method of parallax images are given. A prototype of the front projection autostereoscopic display is developed, which enhances the brightness and 3D perceptions, and improves space efficiency. The performance of this prototype is evaluated by measuring the luminance and crosstalk distribution along the horizontal direction at the optimum viewing distance. We also propose a rear projection autostereoscopic display. The display consists of eight projectors, a projection screen, and two lenticular sheets. The operation principle and calculation equations are described in detail and the parallax images are corrected by means of homography. A prototype of the rear projection autostereoscopic display is developed. The normalized luminance distributions of viewing zones from the measurement are given. Results agree well with the designed values. The prototype presents high resolution and high brightness 3D images. The research has potential applications in some commercial entertainments and movies for the realistic 3D perceptions.

  12. Alignment, segmentation and 3-D reconstruction of serial sections based on automated algorithm

    NASA Astrophysics Data System (ADS)

    Bian, Weiguo; Tang, Shaojie; Xu, Qiong; Lian, Qin; Wang, Jin; Li, Dichen

    2012-12-01

    A well-defined three-dimensional (3-D) reconstruction of bone-cartilage transitional structures is crucial for the osteochondral restoration. This paper presents an accurate, computationally efficient and fully-automated algorithm for the alignment and segmentation of two-dimensional (2-D) serial to construct the 3-D model of bone-cartilage transitional structures. Entire system includes the following five components: (1) image harvest, (2) image registration, (3) image segmentation, (4) 3-D reconstruction and visualization, and (5) evaluation. A computer program was developed in the environment of Matlab for the automatic alignment and segmentation of serial sections. Automatic alignment algorithm based on the position's cross-correlation of the anatomical characteristic feature points of two sequential sections. A method combining an automatic segmentation and an image threshold processing was applied to capture the regions and structures of interest. SEM micrograph and 3-D model reconstructed directly in digital microscope were used to evaluate the reliability and accuracy of this strategy. The morphology of 3-D model constructed by serial sections is consistent with the results of SEM micrograph and 3-D model of digital microscope.

  13. Complex adaptation-based LDR image rendering for 3D image reconstruction

    NASA Astrophysics Data System (ADS)

    Lee, Sung-Hak; Kwon, Hyuk-Ju; Sohng, Kyu-Ik

    2014-07-01

    A low-dynamic tone-compression technique is developed for realistic image rendering that can make three-dimensional (3D) images similar to realistic scenes by overcoming brightness dimming in the 3D display mode. The 3D surround provides varying conditions for image quality, illuminant adaptation, contrast, gamma, color, sharpness, and so on. In general, gain/offset adjustment, gamma compensation, and histogram equalization have performed well in contrast compression; however, as a result of signal saturation and clipping effects, image details are removed and information is lost on bright and dark areas. Thus, an enhanced image mapping technique is proposed based on space-varying image compression. The performance of contrast compression is enhanced with complex adaptation in a 3D viewing surround combining global and local adaptation. Evaluating local image rendering in view of tone and color expression, noise reduction, and edge compensation confirms that the proposed 3D image-mapping model can compensate for the loss of image quality in the 3D mode.

  14. 3D finite element analysis of porous Ti-based alloy prostheses.

    PubMed

    Mircheski, Ile; Gradišar, Marko

    2016-11-01

    In this paper, novel designs of porous acetabular cups are created and tested with 3D finite element analysis (FEA). The aim is to develop a porous acetabular cup with low effective radial stiffness of the structure, which will be near to the architectural and mechanical behavior of the natural bone. For the realization of this research, a 3D-scanner technology was used for obtaining a 3D-CAD model of the pelvis bone, a 3D-CAD software for creating a porous acetabular cup, and a 3D-FEA software for virtual testing of a novel design of the porous acetabular cup. The results obtained from this research reveal that a porous acetabular cup from Ti-based alloys with 60 ± 5% porosity has the mechanical behavior and effective radial stiffness (Young's modulus in radial direction) that meet and exceed the required properties of the natural bone. The virtual testing with 3D-FEA of a novel design with porous structure during the very early stage of the design and the development of orthopedic implants, enables obtaining a new or improved biomedical implant for a relatively short time and reduced price.

  15. Superabsorbent 3D Scaffold Based on Electrospun Nanofibers for Cartilage Tissue Engineering.

    PubMed

    Chen, Weiming; Chen, Shuai; Morsi, Yosry; El-Hamshary, Hany; El-Newhy, Mohamed; Fan, Cunyi; Mo, Xiumei

    2016-09-21

    Electrospun nanofibers have been used for various biomedical applications. However, electrospinning commonly produces two-dimensional (2D) membranes, which limits the application of nanofibers for the 3D tissue engineering scaffold. In the present study, a porous 3D scaffold (3DS-1) based on electrospun gelatin/PLA nanofibers has been prepared for cartilage tissue regeneration. To further improve the repairing effect of cartilage, a modified scaffold (3DS-2) cross-linked with hyaluronic acid (HA) was also successfully fabricated. The nanofibrous structure, water absorption, and compressive mechanical properties of 3D scaffold were studied. Chondrocytes were cultured on 3D scaffold, and their viability and morphology were examined. 3D scaffolds were also subjected to an in vivo cartilage regeneration study on rabbits using an articular cartilage injury model. The results indicated that 3DS-1 and 3DS-2 exhibited superabsorbent property and excellent cytocompatibility. Both these scaffolds present elastic property in the wet state. An in vivo study showed that 3DS-2 could enhance the repair of cartilage. The present 3D nanofibrous scaffold (3DS-2) would be promising for cartilage tissue engineering application.

  16. A Secret 3D Model Sharing Scheme with Reversible Data Hiding Based on Space Subdivision

    NASA Astrophysics Data System (ADS)

    Tsai, Yuan-Yu

    2016-03-01

    Secret sharing is a highly relevant research field, and its application to 2D images has been thoroughly studied. However, secret sharing schemes have not kept pace with the advances of 3D models. With the rapid development of 3D multimedia techniques, extending the application of secret sharing schemes to 3D models has become necessary. In this study, an innovative secret 3D model sharing scheme for point geometries based on space subdivision is proposed. Each point in the secret point geometry is first encoded into a series of integer values that fall within [0, p - 1], where p is a predefined prime number. The share values are derived by substituting the specified integer values for all coefficients of the sharing polynomial. The surface reconstruction and the sampling concepts are then integrated to derive a cover model with sufficient model complexity for each participant. Finally, each participant has a separate 3D stego model with embedded share values. Experimental results show that the proposed technique supports reversible data hiding and the share values have higher levels of privacy and improved robustness. This technique is simple and has proven to be a feasible secret 3D model sharing scheme.

  17. Performance Analysis of a Low-Cost Triangulation-Based 3d Camera: Microsoft Kinect System

    NASA Astrophysics Data System (ADS)

    . K. Chow, J. C.; Ang, K. D.; Lichti, D. D.; Teskey, W. F.

    2012-07-01

    Recent technological advancements have made active imaging sensors popular for 3D modelling and motion tracking. The 3D coordinates of signalised targets are traditionally estimated by matching conjugate points in overlapping images. Current 3D cameras can acquire point clouds at video frame rates from a single exposure station. In the area of 3D cameras, Microsoft and PrimeSense have collaborated and developed an active 3D camera based on the triangulation principle, known as the Kinect system. This off-the-shelf system costs less than 150 USD and has drawn a lot of attention from the robotics, computer vision, and photogrammetry disciplines. In this paper, the prospect of using the Kinect system for precise engineering applications was evaluated. The geometric quality of the Kinect system as a function of the scene (i.e. variation of depth, ambient light conditions, incidence angle, and object reflectivity) and the sensor (i.e. warm-up time and distance averaging) were analysed quantitatively. This system's potential in human body measurements was tested against a laser scanner and 3D range camera. A new calibration model for simultaneously determining the exterior orientation parameters, interior orientation parameters, boresight angles, leverarm, and object space features parameters was developed and the effectiveness of this calibration approach was explored.

  18. 3D IC TSV-Based Technology: Stress Assessment For Chip Performance

    NASA Astrophysics Data System (ADS)

    Sukharev, Valeriy; Kteyan, Armen; Khachatryan, Nikolay; Hovsepyan, Henrik; Torres, Juan Andres; Choy, Jun-Ho; Markosian, Ara

    2010-11-01

    Potential challenges with managing mechanical stress distributions and the consequent effects on device performance for advanced 3D through-silicon-via (TSV) based technologies are outlined. A set of physics-based compact models of a multi-scale simulation flow for assessment of the mechanical stress across the device layers in the silicon chips stacked and packaged with the 3D TSV technology is proposed. A calibration technique based on fitting to measured transistor electrical characteristics of a custom designed test-chip is proposed.

  19. 3D fluoroscopic image estimation using patient-specific 4DCBCT-based motion models

    NASA Astrophysics Data System (ADS)

    Dhou, S.; Hurwitz, M.; Mishra, P.; Cai, W.; Rottmann, J.; Li, R.; Williams, C.; Wagar, M.; Berbeco, R.; Ionascu, D.; Lewis, J. H.

    2015-05-01

    3D fluoroscopic images represent volumetric patient anatomy during treatment with high spatial and temporal resolution. 3D fluoroscopic images estimated using motion models built using 4DCT images, taken days or weeks prior to treatment, do not reliably represent patient anatomy during treatment. In this study we developed and performed initial evaluation of techniques to develop patient-specific motion models from 4D cone-beam CT (4DCBCT) images, taken immediately before treatment, and used these models to estimate 3D fluoroscopic images based on 2D kV projections captured during treatment. We evaluate the accuracy of 3D fluoroscopic images by comparison to ground truth digital and physical phantom images. The performance of 4DCBCT-based and 4DCT-based motion models are compared in simulated clinical situations representing tumor baseline shift or initial patient positioning errors. The results of this study demonstrate the ability for 4DCBCT imaging to generate motion models that can account for changes that cannot be accounted for with 4DCT-based motion models. When simulating tumor baseline shift and patient positioning errors of up to 5 mm, the average tumor localization error and the 95th percentile error in six datasets were 1.20 and 2.2 mm, respectively, for 4DCBCT-based motion models. 4DCT-based motion models applied to the same six datasets resulted in average tumor localization error and the 95th percentile error of 4.18 and 5.4 mm, respectively. Analysis of voxel-wise intensity differences was also conducted for all experiments. In summary, this study demonstrates the feasibility of 4DCBCT-based 3D fluoroscopic image generation in digital and physical phantoms and shows the potential advantage of 4DCBCT-based 3D fluoroscopic image estimation when there are changes in anatomy between the time of 4DCT imaging and the time of treatment delivery.

  20. Graph-based segmentation for RGB-D data using 3-D geometry enhanced superpixels.

    PubMed

    Yang, Jingyu; Gan, Ziqiao; Li, Kun; Hou, Chunping

    2015-05-01

    With the advances of depth sensing technologies, color image plus depth information (referred to as RGB-D data hereafter) is more and more popular for comprehensive description of 3-D scenes. This paper proposes a two-stage segmentation method for RGB-D data: 1) oversegmentation by 3-D geometry enhanced superpixels and 2) graph-based merging with label cost from superpixels. In the oversegmentation stage, 3-D geometrical information is reconstructed from the depth map. Then, a K-means-like clustering method is applied to the RGB-D data for oversegmentation using an 8-D distance metric constructed from both color and 3-D geometrical information. In the merging stage, treating each superpixel as a node, a graph-based model is set up to relabel the superpixels into semantically-coherent segments. In the graph-based model, RGB-D proximity, texture similarity, and boundary continuity are incorporated into the smoothness term to exploit the correlations of neighboring superpixels. To obtain a compact labeling, the label term is designed to penalize labels linking to similar superpixels that likely belong to the same object. Both the proposed 3-D geometry enhanced superpixel clustering method and the graph-based merging method from superpixels are evaluated by qualitative and quantitative results. By the fusion of color and depth information, the proposed method achieves superior segmentation performance over several state-of-the-art algorithms.

  1. 3D fluoroscopic image estimation using patient-specific 4DCBCT-based motion models

    PubMed Central

    Dhou, Salam; Hurwitz, Martina; Mishra, Pankaj; Cai, Weixing; Rottmann, Joerg; Li, Ruijiang; Williams, Christopher; Wagar, Matthew; Berbeco, Ross; Ionascu, Dan; Lewis, John H.

    2015-01-01

    3D fluoroscopic images represent volumetric patient anatomy during treatment with high spatial and temporal resolution. 3D fluoroscopic images estimated using motion models built using 4DCT images, taken days or weeks prior to treatment, do not reliably represent patient anatomy during treatment. In this study we develop and perform initial evaluation of techniques to develop patient-specific motion models from 4D cone-beam CT (4DCBCT) images, taken immediately before treatment, and use these models to estimate 3D fluoroscopic images based on 2D kV projections captured during treatment. We evaluate the accuracy of 3D fluoroscopic images by comparing to ground truth digital and physical phantom images. The performance of 4DCBCT- and 4DCT- based motion models are compared in simulated clinical situations representing tumor baseline shift or initial patient positioning errors. The results of this study demonstrate the ability for 4DCBCT imaging to generate motion models that can account for changes that cannot be accounted for with 4DCT-based motion models. When simulating tumor baseline shift and patient positioning errors of up to 5 mm, the average tumor localization error and the 95th percentile error in six datasets were 1.20 and 2.2 mm, respectively, for 4DCBCT-based motion models. 4DCT-based motion models applied to the same six datasets resulted in average tumor localization error and the 95th percentile error of 4.18 and 5.4 mm, respectively. Analysis of voxel-wise intensity differences was also conducted for all experiments. In summary, this study demonstrates the feasibility of 4DCBCT-based 3D fluoroscopic image generation in digital and physical phantoms, and shows the potential advantage of 4DCBCT-based 3D fluoroscopic image estimation when there are changes in anatomy between the time of 4DCT imaging and the time of treatment delivery. PMID:25905722

  2. Artificial intelligence (AI)-based relational matching and multimodal medical image fusion: generalized 3D approaches

    NASA Astrophysics Data System (ADS)

    Vajdic, Stevan M.; Katz, Henry E.; Downing, Andrew R.; Brooks, Michael J.

    1994-09-01

    A 3D relational image matching/fusion algorithm is introduced. It is implemented in the domain of medical imaging and is based on Artificial Intelligence paradigms--in particular, knowledge base representation and tree search. The 2D reference and target images are selected from 3D sets and segmented into non-touching and non-overlapping regions, using iterative thresholding and/or knowledge about the anatomical shapes of human organs. Selected image region attributes are calculated. Region matches are obtained using a tree search, and the error is minimized by evaluating a `goodness' of matching function based on similarities of region attributes. Once the matched regions are found and the spline geometric transform is applied to regional centers of gravity, images are ready for fusion and visualization into a single 3D image of higher clarity.

  3. Shape-based 3D vascular tree extraction for perforator flaps

    NASA Astrophysics Data System (ADS)

    Wen, Quan; Gao, Jean

    2005-04-01

    Perforator flaps have been increasingly used in the past few years for trauma and reconstructive surgical cases. With the thinned perforated flaps, greater survivability and decrease in donor site morbidity have been reported. Knowledge of the 3D vascular tree will provide insight information about the dissection region, vascular territory, and fascia levels. This paper presents a scheme of shape-based 3D vascular tree reconstruction of perforator flaps for plastic surgery planning, which overcomes the deficiencies of current existing shape-based interpolation methods by applying rotation and 3D repairing. The scheme has the ability to restore the broken parts of the perforator vascular tree by using a probability-based adaptive connection point search (PACPS) algorithm with minimum human intervention. The experimental results evaluated by both synthetic and 39 harvested cadaver perforator flaps show the promise and potential of proposed scheme for plastic surgery planning.

  4. 3D Game-Based Learning System for Improving Learning Achievement in Software Engineering Curriculum

    ERIC Educational Resources Information Center

    Su,Chung-Ho; Cheng, Ching-Hsue

    2013-01-01

    The advancement of game-based learning has encouraged many related studies, such that students could better learn curriculum by 3-dimension virtual reality. To enhance software engineering learning, this paper develops a 3D game-based learning system to assist teaching and assess the students' motivation, satisfaction and learning achievement. A…

  5. Web-Based Interactive 3D Visualization as a Tool for Improved Anatomy Learning

    ERIC Educational Resources Information Center

    Petersson, Helge; Sinkvist, David; Wang, Chunliang; Smedby, Orjan

    2009-01-01

    Despite a long tradition, conventional anatomy education based on dissection is declining. This study tested a new virtual reality (VR) technique for anatomy learning based on virtual contrast injection. The aim was to assess whether students value this new three-dimensional (3D) visualization method as a learning tool and what value they gain…

  6. Complete calibration of a phase-based 3D imaging system based on fringe projection technique

    NASA Astrophysics Data System (ADS)

    Meng, Shasha; Ma, Haiyan; Zhang, Zonghua; Guo, Tong; Zhang, Sixiang; Hu, Xiaotang

    2011-11-01

    Phase calculation-based 3D imaging systems have been widely studied because of the advantages of non-contact operation, full-field, fast acquisition and automatic data processing. A vital step is calibration, which builds up the relationship between phase map and range image. The existing calibration methods are complicated because of using a precise translating stage or a 3D gauge block. Recently, we presented a simple method to convert phase into depth data by using a polynomial function and a plate having discrete markers on the surface with known distance in between. However, the initial position of all the markers needs to be determined manually and the X, Y coordinates are not calibrated. This paper presents a complete calibration method of phase calculation-based 3D imaging systems by using a plate having discrete markers on the surface with known distance in between. The absolute phase of each pixel can be calculated by projecting fringe pattern onto the plate. Each marker position can be determined by an automatic extraction algorithm, so the relative depth of each pixel to a chosen reference plane can be obtained. Therefore, coefficient set of the polynomial function for each pixel are determined by using the obtained absolute phase and depth data. In the meanwhile, pixel positions and the X, Y coordinates can be established by the parameters of the CCD camera. Experimental results and performance evaluation show that the proposed calibration method can easily build up the relationship between absolute phase map and range image in a simple way.

  7. 3D printing of weft knitted textile based structures by selective laser sintering of nylon powder

    NASA Astrophysics Data System (ADS)

    Beecroft, M.

    2016-07-01

    3D printing is a form of additive manufacturing whereby the building up of layers of material creates objects. The selective laser sintering process (SLS) uses a laser beam to sinter powdered material to create objects. This paper builds upon previous research into 3D printed textile based material exploring the use of SLS using nylon powder to create flexible weft knitted structures. The results show the potential to print flexible textile based structures that exhibit the properties of traditional knitted textile structures along with the mechanical properties of the material used, whilst describing the challenges regarding fineness of printing resolution. The conclusion highlights the potential future development and application of such pieces.

  8. Wavelet based Simulation of Reservoir Flow

    NASA Astrophysics Data System (ADS)

    Siddiqi, A. H.; Verma, A. K.; Noor-E-Zahra, Noor-E.-Zahra; Chandiok, Ashish; Hasan, A.

    2009-07-01

    Petroleum reservoirs consist of hydrocarbons and other chemicals trapped in the pores of a rock. The exploration and production of hydrocarbon reservoirs is still the most important technology to develop natural energy resources. Therefore, fluid flow simulators play a key role in order to help oil companies. In fact, simulation is the most important tool to model changes in a reservoir over the time. The main problem in petroleum reservoir simulation is to model the displacement of one fluid by another within a porous medium. A typical problem is characterized by the injection of a wetting fluid, for example water into the reservoir at a particular location displacing to the non wetting fluid, for example oil, which is extracted or produced at another location. Buckley-Leverett equation [1] models this process and its numerical simulation and visualization is of paramount importance. There are several numerical methods applied for numerical solution of partial differential equations modeling real world problems. We review in this paper the numerical solution of Buckley-Leverett equation for flat and non flat structures with special focus on wavelet method. We also indicate a few new avenues for further research.

  9. Mechanosensing of cells in 3D gel matrices based on natural and synthetic materials.

    PubMed

    Shan, Jieling; Chi, Qingjia; Wang, Hongbing; Huang, Qiping; Yang, Li; Yu, Guanglei; Zou, Xiaobing

    2014-11-01

    Cells in vivo typically are found in 3D matrices, the mechanical stiffness of which is important to the cell and tissue-scale biological processes. Although it is well characterized that as to how cells sense matrix stiffness in 2D substrates, the scenario in 3D matrices needs to be explored. Thus, materials that can mimic native 3D environments and possess wide, physiologically relevant elasticity are highly desirable. Natural polymer-based materials and synthetic hydrogels could provide an better 3D platforms to investigate the mechano-response of cells with stiffness comparable to their native environments. However, the limited stiffness range together with interdependence of matrix stiffness and adhesive ligand density are inherent in many kinds of materials, and hinder efforts to demonstrate the true effects contributed by matrix stiffness. These problems have been addressed by the recently emerging exquisitely designed materials based on native matrix components, designer matrices, and synthetic polymers. In this review, a variety of materials with a wide stiffness range that mimic the mechanical environment of native 3D matrices and the independent affection of stiffness for cellular behavior and tissue-level processes are discussed.

  10. Laser nanostructuring 3-D bioconstruction based on carbon nanotubes in a water matrix of albumin

    NASA Astrophysics Data System (ADS)

    Gerasimenko, Alexander Y.; Ichkitidze, Levan P.; Podgaetsky, Vitaly M.; Savelyev, Mikhail S.; Selishchev, Sergey V.

    2016-04-01

    3-D bioconstructions were created using the evaporation method of the water-albumin solution with carbon nanotubes (CNTs) by the continuous and pulsed femtosecond laser radiation. It is determined that the volume structure of the samples created by the femtosecond radiation has more cavities than the one created by the continuous radiation. The average diameter for multi-walled carbon nanotubes (MWCNTs) samples was almost two times higher (35-40 nm) than for single-walled carbon nanotubes (SWCNTs) samples (20-30 nm). The most homogenous 3-D bioconstruction was formed from MWCNTs by the continuous laser radiation. The hardness of such samples totaled up to 370 MPa at the nanoscale. High strength properties and the resistance of the 3-D bioconstructions produced by the laser irradiation depend on the volume nanotubes scaffold forming inside them. The scaffold was formed by the electric field of the directed laser irradiation. The covalent bond energy between the nanotube carbon molecule and the oxygen of the bovine serum albumin aminoacid residue amounts 580 kJ/mol. The 3-D bioconstructions based on MWCNTs and SWCNTs becomes overgrown with the cells (fibroblasts) over the course of 72 hours. The samples based on the both types of CNTs are not toxic for the cells and don't change its normal composition and structure. Thus the 3-D bioconstructions that are nanostructured by the pulsed and continuous laser radiation can be applied as implant materials for the recovery of the connecting tissues of the living body.

  11. High Accuracy Acquisition of 3-D Flight Trajectory of Individual Insect Based on Phase Measurement.

    PubMed

    Hu, Cheng; Deng, Yunkai; Wang, Rui; Liu, Changjiang; Long, Teng

    2016-12-17

    Accurate acquisition of 3-D flight trajectory of individual insect could be of benefit to the research of insect migration behaviors and the development of migratory entomology. This paper proposes a novel method to acquire 3-D flight trajectory of individual insect. First, based on the high range resolution synthesizing and the Doppler coherent processing, insects can be detected effectively, and the range resolution and velocity resolution are combined together to discriminate insects. Then, high accuracy range measurement with the carrier phase is proposed. The range measurement accuracy can reach millimeter level and benefits the acquisition of 3-D trajectory information significantly. Finally, based on the multi-baselines interferometry theory, the azimuth and elevation angles can be obtained with high accuracy. Simulation results prove that the retrieval accuracy of a simulated target's 3-D coordinates can reach centimeter level. Experiments utilizing S-band radar in an anechoic chamber were taken and results showed that the insects' flight behaviors and 3-D coordinates' variation matched the practical cases well. In conclusion, both the simulated and experimental datasets validate the feasibility of the proposed method, which could be a novel measurement way of monitoring flight trajectory of aerial free-fly insects.

  12. High Accuracy Acquisition of 3-D Flight Trajectory of Individual Insect Based on Phase Measurement

    PubMed Central

    Hu, Cheng; Deng, Yunkai; Wang, Rui; Liu, Changjiang; Long, Teng

    2016-01-01

    Accurate acquisition of 3-D flight trajectory of individual insect could be of benefit to the research of insect migration behaviors and the development of migratory entomology. This paper proposes a novel method to acquire 3-D flight trajectory of individual insect. First, based on the high range resolution synthesizing and the Doppler coherent processing, insects can be detected effectively, and the range resolution and velocity resolution are combined together to discriminate insects. Then, high accuracy range measurement with the carrier phase is proposed. The range measurement accuracy can reach millimeter level and benefits the acquisition of 3-D trajectory information significantly. Finally, based on the multi-baselines interferometry theory, the azimuth and elevation angles can be obtained with high accuracy. Simulation results prove that the retrieval accuracy of a simulated target’s 3-D coordinates can reach centimeter level. Experiments utilizing S-band radar in an anechoic chamber were taken and results showed that the insects’ flight behaviors and 3-D coordinates’ variation matched the practical cases well. In conclusion, both the simulated and experimental datasets validate the feasibility of the proposed method, which could be a novel measurement way of monitoring flight trajectory of aerial free-fly insects. PMID:27999317

  13. Relevance of PEG in PLA-based blends for tissue engineering 3D-printed scaffolds.

    PubMed

    Serra, Tiziano; Ortiz-Hernandez, Monica; Engel, Elisabeth; Planell, Josep A; Navarro, Melba

    2014-05-01

    Achieving high quality 3D-printed structures requires establishing the right printing conditions. Finding processing conditions that satisfy both the fabrication process and the final required scaffold properties is crucial. This work stresses the importance of studying the outcome of the plasticizing effect of PEG on PLA-based blends used for the fabrication of 3D-direct-printed scaffolds for tissue engineering applications. For this, PLA/PEG blends with 5, 10 and 20% (w/w) of PEG and PLA/PEG/bioactive CaP glass composites were processed in the form of 3D rapid prototyping scaffolds. Surface analysis and differential scanning calorimetry revealed a rearrangement of polymer chains and a topography, wettability and elastic modulus increase of the studied surfaces as PEG was incorporated. Moreover, addition of 10 and 20% PEG led to non-uniform 3D structures with lower mechanical properties. In vitro degradation studies showed that the inclusion of PEG significantly accelerated the degradation rate of the material. Results indicated that the presence of PEG not only improves PLA processing but also leads to relevant surface, geometrical and structural changes including modulation of the degradation rate of PLA-based 3D printed scaffolds.

  14. 3D texture-based classification applied on brain white matter lesions on MR images

    NASA Astrophysics Data System (ADS)

    Leite, Mariana; Gobbi, David; Salluzi, Marina; Frayne, Richard; Lotufo, Roberto; Rittner, Letícia

    2016-03-01

    Lesions in the brain white matter are among the most frequently observed incidental findings on MR images. This paper presents a 3D texture-based classification to distinguish normal appearing white matter from white matter containing lesions, and compares it with the 2D approach. Texture analysis were based on 55 texture attributes extracted from gray-level histogram, gray-level co-occurrence matrix, run-length matrix and gradient. The results show that the 3D approach achieves an accuracy rate of 99.28%, against 97.41% of the 2D approach by using a support vector machine classifier. Furthermore, the most discriminating texture attributes on both 2D and 3D cases were obtained from the image histogram and co-occurrence matrix.

  15. Computer-Assisted Hepatocellular Carcinoma Ablation Planning Based on 3-D Ultrasound Imaging.

    PubMed

    Li, Kai; Su, Zhongzhen; Xu, Erjiao; Guan, Peishan; Li, Liu-Jun; Zheng, Rongqin

    2016-08-01

    To evaluate computer-assisted hepatocellular carcinoma (HCC) ablation planning based on 3-D ultrasound, 3-D ultrasound images of 60 HCC lesions from 58 patients were obtained and transferred to a research toolkit. Compared with virtual manual ablation planning (MAP), virtual computer-assisted ablation planning (CAP) consumed less time and needle insertion numbers and exhibited a higher rate of complete tumor coverage and lower rate of critical structure injury. In MAP, junior operators used less time, but had more critical structure injury than senior operators. For large lesions, CAP performed better than MAP. For lesions near critical structures, CAP resulted in better outcomes than MAP. Compared with MAP, CAP based on 3-D ultrasound imaging was more effective and achieved a higher rate of complete tumor coverage and a lower rate of critical structure injury; it is especially useful for junior operators and with large lesions, and lesions near critical structures.

  16. Gradient-based 3D-2D registration of cerebral angiograms

    NASA Astrophysics Data System (ADS)

    Mitrović, Uroš; Markelj, Primož; Likar, Boštjan; Miloševič, Zoran; Pernuš, Franjo

    2011-03-01

    Endovascular treatment of cerebral aneurysms and arteriovenous malformations (AVM) involves navigation of a catheter through the femoral artery and vascular system into the brain and into the aneurysm or AVM. Intra-interventional navigation utilizes digital subtraction angiography (DSA) to visualize vascular structures and X-ray fluoroscopy to localize the endovascular components. Due to the two-dimensional (2D) nature of the intra-interventional images, navigation through a complex three-dimensional (3D) structure is a demanding task. Registration of pre-interventional MRA, CTA, or 3D-DSA images and intra-interventional 2D DSA images can greatly enhance visualization and navigation. As a consequence of better navigation in 3D, the amount of required contrast medium and absorbed dose could be significantly reduced. In the past, development and evaluation of 3D-2D registration methods received considerable attention. Several validation image databases and evaluation criteria were created and made publicly available in the past. However, applications of 3D-2D registration methods to cerebral angiograms and their validation are rather scarce. In this paper, the 3D-2D robust gradient reconstruction-based (RGRB) registration algorithm is applied to CTA and DSA images and analyzed. For the evaluation purposes five image datasets, each comprised of a 3D CTA and several 2D DSA-like digitally reconstructed radiographs (DRRs) generated from the CTA, with accurate gold standard registrations were created. A total of 4000 registrations on these five datasets resulted in mean mTRE values between 0.07 and 0.59 mm, capture ranges between 6 and 11 mm and success rates between 61 and 88% using a failure threshold of 2 mm.

  17. Lithologic identification & mapping test based on 3D inversion of magnetic and gravity

    NASA Astrophysics Data System (ADS)

    Yan, Jiayong; Lv, Qingtian; Qi, Guang; Zhao, Jinhua; Zhang, Yongqian

    2016-04-01

    Though lithologic identification & mapping to achieve ore concentration district transparent within 5km depth is the main way to realize deep fine structures study, to explore deep mineral resources and to reveal metallogenic regularity of large-scale ore district . Owing to the wide covered area, high sampling density and mature three-dimensional inversion algorithm of gravity and magnetic data, so gravity and magnetic inversion become the most likely way to achieve three-dimensional lithologic mapping at the present stage. In this paper, we take Lu-zong(Lujiang county to Zongyang county in Anhui province ,east China) ore district as a case, we proposed lithologic mapping flow based 3D inversion of gravity magnetic and then carry out the lithologic mapping test. Lithologic identification & mapping flow is as follows: 1. Analysis relations between lithology and density and magnetic susceptibility by cross plot. 2.Extracting appropriate residual anomalies from high-precision Bourger gravity and aeromagnetic. 3.Use same mesh, do 3D magnetic and gravity inversion respectively under prior information constrained, and then invert susceptibility and density 3D model. 4. According setp1, construct logical topology operations between density 3D model and susceptibility. 5.Use the logical operations, identify lithogies cell by cell in 3D mesh, and then get 3D lithological model. According this flow, we obtained three-dimensional distribution of five main type lithologies in the Lu-Zong ore district within 5km depth. The result of lithologic mapping not only showed that the shallow characteristics and surface geological mapping are basically Coincide,more importantly ,it reveals the deeper lithologic changes.The lithlogical model make up the insufficient of surface geological mapping. The lithologic mapping test results in Lu-Zong ore concentration district showed that lithological mapping using 3D inversion of gravity and magnetic is a effective method to reveal the

  18. 2-D Versus 3-D Cross-Correlation-Based Radial and Circumferential Strain Estimation Using Multiplane 2-D Ultrafast Ultrasound in a 3-D Atherosclerotic Carotid Artery Model.

    PubMed

    Fekkes, Stein; Swillens, Abigail E S; Hansen, Hendrik H G; Saris, Anne E C M; Nillesen, Maartje M; Iannaccone, Francesco; Segers, Patrick; de Korte, Chris L

    2016-10-01

    Three-dimensional (3-D) strain estimation might improve the detection and localization of high strain regions in the carotid artery (CA) for identification of vulnerable plaques. This paper compares 2-D versus 3-D displacement estimation in terms of radial and circumferential strain using simulated ultrasound (US) images of a patient-specific 3-D atherosclerotic CA model at the bifurcation embedded in surrounding tissue generated with ABAQUS software. Global longitudinal motion was superimposed to the model based on the literature data. A Philips L11-3 linear array transducer was simulated, which transmitted plane waves at three alternating angles at a pulse repetition rate of 10 kHz. Interframe (IF) radio-frequency US data were simulated in Field II for 191 equally spaced longitudinal positions of the internal CA. Accumulated radial and circumferential displacements were estimated using tracking of the IF displacements estimated by a two-step normalized cross-correlation method and displacement compounding. Least-squares strain estimation was performed to determine accumulated radial and circumferential strain. The performance of the 2-D and 3-D methods was compared by calculating the root-mean-squared error of the estimated strains with respect to the reference strains obtained from the model. More accurate strain images were obtained using the 3-D displacement estimation for the entire cardiac cycle. The 3-D technique clearly outperformed the 2-D technique in phases with high IF longitudinal motion. In fact, the large IF longitudinal motion rendered it impossible to accurately track the tissue and cumulate strains over the entire cardiac cycle with the 2-D technique.

  19. Dependence and risk assessment for oil prices and exchange rate portfolios: A wavelet based approach

    NASA Astrophysics Data System (ADS)

    Aloui, Chaker; Jammazi, Rania

    2015-10-01

    In this article, we propose a wavelet-based approach to accommodate the stylized facts and complex structure of financial data, caused by frequent and abrupt changes of markets and noises. Specifically, we show how the combination of both continuous and discrete wavelet transforms with traditional financial models helps improve portfolio's market risk assessment. In the empirical stage, three wavelet-based models (wavelet-EGARCH with dynamic conditional correlations, wavelet-copula, and wavelet-extreme value) are considered and applied to crude oil price and US dollar exchange rate data. Our findings show that the wavelet-based approach provides an effective and powerful tool for detecting extreme moments and improving the accuracy of VaR and Expected Shortfall estimates of oil-exchange rate portfolios after noise is removed from the original data.

  20. Field lens multiplexing in holographic 3D displays by using Bragg diffraction based volume gratings

    NASA Astrophysics Data System (ADS)

    Fütterer, G.

    2016-11-01

    Applications, which can profit from holographic 3D displays, are the visualization of 3D data, computer-integrated manufacturing, 3D teleconferencing and mobile infotainment. However, one problem of holographic 3D displays, which are e.g. based on space bandwidth limited reconstruction of wave segments, is to realize a small form factor. Another problem is to provide a reasonable large volume for the user placement, which means to provide an acceptable freedom of movement. Both problems should be solved without decreasing the image quality of virtual and real object points, which are generated within the 3D display volume. A diffractive optical design using thick hologram gratings, which can be referred to as Bragg diffraction based volume gratings, can provide a small form factor and high definition natural viewing experience of 3D objects. A large collimated wave can be provided by an anamorphic backlight unit. The complex valued spatial light modulator add local curvatures to the wave field he is illuminated with. The modulated wave field is focused onto to the user plane by using a volume grating based field lens. Active type liquid crystal gratings provide 1D fine tracking of approximately +/- 8° deg. Diffractive multiplex has to be implemented for each color and for a set of focus functions providing coarse tracking. Boundary conditions of the diffractive multiplexing are explained. This is done in regards to the display layout and by using the coupled wave theory (CWT). Aspects of diffractive cross talk and its suppression will be discussed including longitudinal apodized volume gratings.

  1. Electro-bending characterization of adaptive 3D fiber reinforced plastics based on shape memory alloys

    NASA Astrophysics Data System (ADS)

    Ashir, Moniruddoza; Hahn, Lars; Kluge, Axel; Nocke, Andreas; Cherif, Chokri

    2016-03-01

    The industrial importance of fiber reinforced plastics (FRPs) is growing steadily in recent years, which are mostly used in different niche products, has been growing steadily in recent years. The integration of sensors and actuators in FRP is potentially valuable for creating innovative applications and therefore the market acceptance of adaptive FRP is increasing. In particular, in the field of highly stressed FRP, structural integrated systems for continuous component parts monitoring play an important role. This presented work focuses on the electro-mechanical characterization of adaptive three-dimensional (3D)FRP with integrated textile-based actuators. Here, the friction spun hybrid yarn, consisting of shape memory alloy (SMA) in wire form as core, serves as an actuator. Because of the shape memory effect, the SMA-hybrid yarn returns to its original shape upon heating that also causes the deformation of adaptive 3D FRP. In order to investigate the influences of the deformation behavior of the adaptive 3D FRP, investigations in this research are varied according to the structural parameters such as radius of curvature of the adaptive 3D FRP, fabric types and number of layers of the fabric in the composite. Results show that reproducible deformations can be realized with adaptive 3D FRP and that structural parameters have a significant impact on the deformation capability.

  2. Extracting valley-ridge lines from point-cloud-based 3D fingerprint models.

    PubMed

    Pang, Xufang; Song, Zhan; Xie, Wuyuan

    2013-01-01

    3D fingerprinting is an emerging technology with the distinct advantage of touchless operation. More important, 3D fingerprint models contain more biometric information than traditional 2D fingerprint images. However, current approaches to fingerprint feature detection usually must transform the 3D models to a 2D space through unwrapping or other methods, which might introduce distortions. A new approach directly extracts valley-ridge features from point-cloud-based 3D fingerprint models. It first applies the moving least-squares method to fit a local paraboloid surface and represent the local point cloud area. It then computes the local surface's curvatures and curvature tensors to facilitate detection of the potential valley and ridge points. The approach projects those points to the most likely valley-ridge lines, using statistical means such as covariance analysis and cross correlation. To finally extract the valley-ridge lines, it grows the polylines that approximate the projected feature points and removes the perturbations between the sampled points. Experiments with different 3D fingerprint models demonstrate this approach's feasibility and performance.

  3. 3D watershed-based segmentation of internal structures within MR brain images

    NASA Astrophysics Data System (ADS)

    Bueno, Gloria; Musse, Olivier; Heitz, Fabrice; Armspach, Jean-Paul

    2000-06-01

    In this paper an image-based method founded on mathematical morphology is presented in order to facilitate the segmentation of cerebral structures on 3D magnetic resonance images (MRIs). The segmentation is described as an immersion simulation, applied to the modified gradient image, modeled by a generated 3D region adjacency graph (RAG). The segmentation relies on two main processes: homotopy modification and contour decision. The first one is achieved by a marker extraction stage where homogeneous 3D regions are identified in order to attribute an influence zone only to relevant minima of the image. This stage uses contrasted regions from morphological reconstruction and labeled flat regions constrained by the RAG. The goal of the decision stage is to precisely locate the contours of regions detected by the marker extraction. This decision is performed by a 3D extension of the watershed transform. Upon completion of the segmentation, the outcome of the preceding process is presented to the user for manual selection of the structures of interest (SOI). Results of this approach are described and illustrated with examples of segmented 3D MRIs of the human head.

  4. 3-D world modeling based on combinatorial geometry for autonomous robot navigation

    SciTech Connect

    Goldstein, M.; Pin, F.G.; de Saussure, G.; Weisbin, C.R.

    1987-01-01

    In applications of robotics to surveillance and mapping at nuclear facilities, the scene to be described is fundamentally three-dimensional. Usually, only partial information concerning the 3-D environment is known a-priori. Using an autonomous robot, this information may be updated using range data to provide an accurate model of the environment. Range data quantify the distances from the sensor focal plane to the object surface. In other words, the 3-D coordinates of discrete points on the object surface are known. The approach proposed herein for 3-D world modeling is based on the Combinatorial Geometry (C.G.) Method which is widely used in Monte Carlo particle transport calculations. First, each measured point on the object surface is surrounded by a small solid sphere with a radius determined by the range to that point. Then, the 3-D shapes of the visible surfaces are obtained by taking the (Boolean) union of all the spheres. The result is a concise and unambiguous representation of the object's boundary surfaces. The distances from discrete points on the robot's boundary surface to various objects are calculated effectively using the C.G. type of representation. This feature is particularly useful for navigation purposes. The efficiency of the proposed approach is illustrated by a simulation of a spherical robot navigating in a 3-D room with several static obstacles.

  5. 3-D Laser-Based Multiclass and Multiview Object Detection in Cluttered Indoor Scenes.

    PubMed

    Zhang, Xuesong; Zhuang, Yan; Hu, Huosheng; Wang, Wei

    2017-01-01

    This paper investigates the problem of multiclass and multiview 3-D object detection for service robots operating in a cluttered indoor environment. A novel 3-D object detection system using laser point clouds is proposed to deal with cluttered indoor scenes with a fewer and imbalanced training data. Raw 3-D point clouds are first transformed to 2-D bearing angle images to reduce the computational cost, and then jointly trained multiple object detectors are deployed to perform the multiclass and multiview 3-D object detection. The reclassification technique is utilized on each detected low confidence bounding box in the system to reduce false alarms in the detection. The RUS-SMOTEboost algorithm is used to train a group of independent binary classifiers with imbalanced training data. Dense histograms of oriented gradients and local binary pattern features are combined as a feature set for the reclassification task. Based on the dalian university of technology (DUT)-3-D data set taken from various office and household environments, experimental results show the validity and good performance of the proposed method.

  6. Structure light telecentric stereoscopic vision 3D measurement system based on Scheimpflug condition

    NASA Astrophysics Data System (ADS)

    Mei, Qing; Gao, Jian; Lin, Hui; Chen, Yun; Yunbo, He; Wang, Wei; Zhang, Guanjin; Chen, Xin

    2016-11-01

    We designed a new three-dimensional (3D) measurement system for micro components: a structure light telecentric stereoscopic vision 3D measurement system based on the Scheimpflug condition. This system creatively combines the telecentric imaging model and the Scheimpflug condition on the basis of structure light stereoscopic vision, having benefits of a wide measurement range, high accuracy, fast speed, and low price. The system measurement range is 20 mm×13 mm×6 mm, the lateral resolution is 20 μm, and the practical vertical resolution reaches 2.6 μm, which is close to the theoretical value of 2 μm and well satisfies the 3D measurement needs of micro components such as semiconductor devices, photoelectron elements, and micro-electromechanical systems. In this paper, we first introduce the principle and structure of the system and then present the system calibration and 3D reconstruction. We then present an experiment that was performed for the 3D reconstruction of the surface topography of a wafer, followed by a discussion. Finally, the conclusions are presented.

  7. Wavelet-based image analysis system for soil texture analysis

    NASA Astrophysics Data System (ADS)

    Sun, Yun; Long, Zhiling; Jang, Ping-Rey; Plodinec, M. John

    2003-05-01

    Soil texture is defined as the relative proportion of clay, silt and sand found in a given soil sample. It is an important physical property of soil that affects such phenomena as plant growth and agricultural fertility. Traditional methods used to determine soil texture are either time consuming (hydrometer), or subjective and experience-demanding (field tactile evaluation). Considering that textural patterns observed at soil surfaces are uniquely associated with soil textures, we propose an innovative approach to soil texture analysis, in which wavelet frames-based features representing texture contents of soil images are extracted and categorized by applying a maximum likelihood criterion. The soil texture analysis system has been tested successfully with an accuracy of 91% in classifying soil samples into one of three general categories of soil textures. In comparison with the common methods, this wavelet-based image analysis approach is convenient, efficient, fast, and objective.

  8. Medical image compression algorithm based on wavelet transform

    NASA Astrophysics Data System (ADS)

    Chen, Minghong; Zhang, Guoping; Wan, Wei; Liu, Minmin

    2005-02-01

    With rapid development of electronic imaging and multimedia technology, the telemedicine is applied to modern medical servings in the hospital. Digital medical image is characterized by high resolution, high precision and vast data. The optimized compression algorithm can alleviate restriction in the transmission speed and data storage. This paper describes the characteristics of human vision system based on the physiology structure, and analyses the characteristics of medical image in the telemedicine, then it brings forward an optimized compression algorithm based on wavelet zerotree. After the image is smoothed, it is decomposed with the haar filters. Then the wavelet coefficients are quantified adaptively. Therefore, we can maximize efficiency of compression and achieve better subjective visual image. This algorithm can be applied to image transmission in the telemedicine. In the end, we examined the feasibility of this algorithm with an image transmission experiment in the network.

  9. Impact of 3-D printed PLA- and chitosan-based scaffolds on human monocyte/macrophage responses: unraveling the effect of 3-D structures on inflammation.

    PubMed

    Almeida, Catarina R; Serra, Tiziano; Oliveira, Marta I; Planell, Josep A; Barbosa, Mário A; Navarro, Melba

    2014-02-01

    Recent studies have pointed towards a decisive role of inflammation in triggering tissue repair and regeneration, while at the same time it is accepted that an exacerbated inflammatory response may lead to rejection of an implant. Within this context, understanding and having the capacity to regulate the inflammatory response elicited by 3-D scaffolds aimed for tissue regeneration is crucial. This work reports on the analysis of the cytokine profile of human monocytes/macrophages in contact with biodegradable 3-D scaffolds with different surface properties, architecture and controlled pore geometry, fabricated by 3-D printing technology. Fabrication processes were optimized to create four different 3-D platforms based on polylactic acid (PLA), PLA/calcium phosphate glass or chitosan. Cytokine secretion and cell morphology of human peripheral blood monocytes allowed to differentiate on the different matrices were analyzed. While all scaffolds supported monocyte/macrophage adhesion and stimulated cytokine production, striking differences between PLA-based and chitosan scaffolds were found, with chitosan eliciting increased secretion of tumor necrosis factor (TNF)-α, while PLA-based scaffolds induced higher production of interleukin (IL)-6, IL-12/23 and IL-10. Even though the material itself induced the biggest differences, the scaffold geometry also impacted on TNF-α and IL-12/23 production, with chitosan scaffolds having larger pores and wider angles leading to a higher secretion of these pro-inflammatory cytokines. These findings strengthen the appropriateness of these 3-D platforms to study modulation of macrophage responses by specific parameters (chemistry, topography, scaffold architecture).

  10. 3D Printed Modeling of the Mitral Valve for Catheter-Based Structural Interventions.

    PubMed

    Vukicevic, Marija; Puperi, Daniel S; Jane Grande-Allen, K; Little, Stephen H

    2017-02-01

    As catheter-based structural heart interventions become increasingly complex, the ability to effectively model patient-specific valve geometry as well as the potential interaction of an implanted device within that geometry will become increasingly important. Our aim with this investigation was to combine the technologies of high-spatial resolution cardiac imaging, image processing software, and fused multi-material 3D printing, to demonstrate that patient-specific models of the mitral valve apparatus could be created to facilitate functional evaluation of novel trans-catheter mitral valve repair strategies. Clinical 3D transesophageal echocardiography and computed tomography images were acquired for three patients being evaluated for a catheter-based mitral valve repair. Target anatomies were identified, segmented and reconstructed into 3D patient-specific digital models. For each patient, the mitral valve apparatus was digitally reconstructed from a single or fused imaging data set. Using multi-material 3D printing methods, patient-specific anatomic replicas of the mitral valve were created. 3D print materials were selected based on the mechanical testing of elastomeric TangoPlus materials (Stratasys, Eden Prairie, Minnesota, USA) and were compared to freshly harvested porcine leaflet tissue. The effective bending modulus of healthy porcine MV tissue was significantly less than the bending modulus of TangoPlus (p < 0.01). All TangoPlus varieties were less stiff than the maximum tensile elastic modulus of mitral valve tissue (3697.2 ± 385.8 kPa anterior leaflet; 2582.1 ± 374.2 kPa posterior leaflet) (p < 0.01). However, the slopes of the stress-strain toe regions of the mitral valve tissues (532.8 ± 281.9 kPa anterior leaflet; 389.0 ± 156.9 kPa posterior leaflet) were not different than those of the Shore 27, Shore 35, and Shore 27 with Shore 35 blend TangoPlus material (p > 0.95). We have demonstrated that patient-specific mitral valve models can be

  11. Special subpixel arrangement-based 3D display with high horizontal resolution.

    PubMed

    Lv, Guo-Jiao; Wang, Qiong-Hua; Zhao, Wu-Xiang; Wu, Fei

    2014-11-01

    A special subpixel arrangement-based 3D display is proposed. This display consists of a 2D display panel and a parallax barrier. On the 2D display panel, subpixels have a special arrangement, so they can redefine the formation of color pixels. This subpixel arrangement can bring about triple horizontal resolution for a conventional 2D display panel. Therefore, when these pixels are modulated by the parallax barrier, the 3D images formed also have triple horizontal resolution. A prototype of this display is developed. Experimental results show that this display with triple horizontal resolution can produce a better display effect than the conventional one.

  12. Computerized lung nodule detection using 3D feature extraction and learning based algorithms.

    PubMed

    Ozekes, Serhat; Osman, Onur

    2010-04-01

    In this paper, a Computer Aided Detection (CAD) system based on three-dimensional (3D) feature extraction is introduced to detect lung nodules. First, eight directional search was applied in order to extract regions of interests (ROIs). Then, 3D feature extraction was performed which includes 3D connected component labeling, straightness calculation, thickness calculation, determining the middle slice, vertical and horizontal widths calculation, regularity calculation, and calculation of vertical and horizontal black pixel ratios. To make a decision for each ROI, feed forward neural networks (NN), support vector machines (SVM), naive Bayes (NB) and logistic regression (LR) methods were used. These methods were trained and tested via k-fold cross validation, and results were compared. To test the performance of the proposed system, 11 cases, which were taken from Lung Image Database Consortium (LIDC) dataset, were used. ROC curves were given for all methods and 100% detection sensitivity was reached except naive Bayes.

  13. Organ printing: computer-aided jet-based 3D tissue engineering.

    PubMed

    Mironov, Vladimir; Boland, Thomas; Trusk, Thomas; Forgacs, Gabor; Markwald, Roger R

    2003-04-01

    Tissue engineering technology promises to solve the organ transplantation crisis. However, assembly of vascularized 3D soft organs remains a big challenge. Organ printing, which we define as computer-aided, jet-based 3D tissue-engineering of living human organs, offers a possible solution. Organ printing involves three sequential steps: pre-processing or development of "blueprints" for organs; processing or actual organ printing; and postprocessing or organ conditioning and accelerated organ maturation. A cell printer that can print gels, single cells and cell aggregates has been developed. Layer-by-layer sequentially placed and solidified thin layers of a thermo-reversible gel could serve as "printing paper". Combination of an engineering approach with the developmental biology concept of embryonic tissue fluidity enables the creation of a new rapid prototyping 3D organ printing technology, which will dramatically accelerate and optimize tissue and organ assembly.

  14. Microfluidic 3D cell culture: potential application for tissue-based bioassays

    PubMed Central

    Li, XiuJun (James); Valadez, Alejandra V.; Zuo, Peng; Nie, Zhihong

    2014-01-01

    Current fundamental investigations of human biology and the development of therapeutic drugs, commonly rely on two-dimensional (2D) monolayer cell culture systems. However, 2D cell culture systems do not accurately recapitulate the structure, function, physiology of living tissues, as well as highly complex and dynamic three-dimensional (3D) environments in vivo. The microfluidic technology can provide micro-scale complex structures and well-controlled parameters to mimic the in vivo environment of cells. The combination of microfluidic technology with 3D cell culture offers great potential for in vivo-like tissue-based applications, such as the emerging organ-on-a-chip system. This article will review recent advances in microfluidic technology for 3D cell culture and their biological applications. PMID:22793034

  15. Edge-based intramode selection for depth-map coding in 3D-HEVC.

    PubMed

    Park, Chun-Su

    2015-01-01

    The 3D video extension of High Efficiency Video Coding (3D-HEVC) is the state-of-the-art video coding standard for the compression of the multiview video plus depth format. In the 3D-HEVC design, new depth-modeling modes (DMMs) are utilized together with the existing intraprediction modes for depth intracoding. The DMMs can provide more accurate prediction signals and thereby achieve better compression efficiency. However, testing the DMMs in the intramode decision process causes a drastic increase in the computational complexity. In this paper, we propose a fast mode decision algorithm for depth intracoding. The proposed algorithm first performs a simple edge classification in the Hadamard transform domain. Then, based on the edge classification results, the proposed algorithm selectively omits unnecessary DMMs in the mode decision process. Experimental results demonstrate that the proposed algorithm speeds up the mode decision process by up to 37.65% with negligible loss of coding efficiency.

  16. FPGA-based real-time anisotropic diffusion filtering of 3D ultrasound images

    NASA Astrophysics Data System (ADS)

    Castro-Pareja, Carlos R.; Dandekar, Omkar S.; Shekhar, Raj

    2005-02-01

    Three-dimensional ultrasonic imaging, especially the emerging real-time version of it, is particularly valuable in medical applications such as echocardiography, obstetrics and surgical navigation. A known problem with ultrasound images is their high level of speckle noise. Anisotropic diffusion filtering has been shown to be effective in enhancing the visual quality of 3D ultrasound images and as preprocessing prior to advanced image processing. However, due to its arithmetic complexity and the sheer size of 3D ultrasound images, it is not possible to perform online, real-time anisotropic diffusion filtering using standard software implementations. We present an FPGA-based architecture that allows performing anisotropic diffusion filtering of 3D images at acquisition rates, thus enabling the use of this filtering technique in real-time applications, such as visualization, registration and volume rendering.

  17. The optimizations of CGH generation algorithms based on multiple GPUs for 3D dynamic holographic display

    NASA Astrophysics Data System (ADS)

    Yang, Dan; Liu, Juan; Zhang, Yingxi; Li, Xin; Wang, Yongtian

    2016-10-01

    Holographic display has been considered as a promising display technology. Currently, low-speed generation of holograms with big holographic data is one of crucial bottlenecks for three dimensional (3D) dynamic holographic display. To solve this problem, the acceleration method computation platform is presented based on look-up table point source method. The computer generated holograms (CGHs) acquisition is sped up by offline file loading and inline calculation optimization, where a pure phase CGH with gigabyte data is encoded to record an object with 10 MB sampling data. Both numerical simulation and optical experiment demonstrate that the CGHs with 1920×1080 resolution by the proposed method can be applied to the 3D objects reconstruction with high quality successfully. It is believed that the CGHs with huge data can be generated by the proposed method with high speed for 3D dynamic holographic display in near future.

  18. Principle and characteristics of 3D display based on random source constructive interference.

    PubMed

    Li, Zhiyang

    2014-07-14

    The paper discusses the principle and characteristics of 3D display based on random source constructive interference (RSCI). The voxels of discrete 3D images are formed in the air via constructive interference of spherical light waves emitted by point light sources (PLSs) that are arranged at random positions to depress high order diffraction. The PLSs might be created by two liquid crystal panels sandwiched between two micro-lens arrays. The point spread function of the system revealed that it is able to reconstruct voxels with diffraction limited resolution over a large field width and depth. The high resolution was confirmed by the experiments. Theoretical analyses also shows that the system could provide a 3D image contrast and gray levels no less than that in liquid crystal panels. Compared with 2D display, it needs only additional depth information, which brings only about 30% data increment.

  19. Radon transform based automatic metal artefacts generation for 3D threat image projection

    NASA Astrophysics Data System (ADS)

    Megherbi, Najla; Breckon, Toby P.; Flitton, Greg T.; Mouton, Andre

    2013-10-01

    Threat Image Projection (TIP) plays an important role in aviation security. In order to evaluate human security screeners in determining threats, TIP systems project images of realistic threat items into the images of the passenger baggage being scanned. In this proof of concept paper, we propose a 3D TIP method which can be integrated within new 3D Computed Tomography (CT) screening systems. In order to make the threat items appear as if they were genuinely located in the scanned bag, appropriate CT metal artefacts are generated in the resulting TIP images according to the scan orientation, the passenger bag content and the material of the inserted threat items. This process is performed in the projection domain using a novel methodology based on the Radon Transform. The obtained results using challenging 3D CT baggage images are very promising in terms of plausibility and realism.

  20. On Limits of Embedding in 3D Images Based on 2D Watson's Model

    NASA Astrophysics Data System (ADS)

    Kavehvash, Zahra; Ghaemmaghami, Shahrokh

    We extend the Watson image quality metric to 3D images through the concept of integral imaging. In the Watson's model, perceptual thresholds for changes to the DCT coefficients of a 2D image are given for information hiding. These thresholds are estimated in a way that the resulting distortion in the 2D image remains undetectable by the human eyes. In this paper, the same perceptual thresholds are estimated for a 3D scene in the integral imaging method. These thresholds are obtained based on the Watson's model using the relation between 2D elemental images and resulting 3D image. The proposed model is evaluated through subjective tests in a typical image steganography scheme.

  1. 3D printed low-loss THz waveguide based on Kagome photonic crystal structure.

    PubMed

    Yang, Jing; Zhao, Jiayu; Gong, Cheng; Tian, Haolin; Sun, Lu; Chen, Ping; Lin, Lie; Liu, Weiwei

    2016-10-03

    A low-loss hollow core terahertz waveguide based on Kagome photonic crystal structure has been designed and fabricated by 3D printing. The 3D printed waveguide has been characterized by using THz time-domain spectroscopy. The results demonstrate that the obtained waveguide features average power propagation loss of 0.02 cm-1 for 0.2-1.0 THz (the minimum is about 0.002 cm-1 at 0.75 THz). More interesting, it could be simply mechanically spliced without any additional alignment, while maintaining the excellent performance. The 3D printing technique will be a promising solution to fabricate Kagome THz waveguide with well controllable characteristics and low cost.

  2. Studies on filtered back-projection imaging reconstruction based on a modified wavelet threshold function

    NASA Astrophysics Data System (ADS)

    Wang, Zhengzi; Ren, Zhong; Liu, Guodong

    2016-10-01

    In this paper, the wavelet threshold denoising method was used into the filtered back-projection algorithm of imaging reconstruction. To overcome the drawbacks of the traditional soft- and hard-threshold functions, a modified wavelet threshold function was proposed. The modified wavelet threshold function has two threshold values and two variants. To verify the feasibility of the modified wavelet threshold function, the standard test experiments were performed by using the software platform of MATLAB. Experimental results show that the filtered back-projection reconstruction algorithm based on the modified wavelet threshold function has better reconstruction effect because of more flexible advantage.

  3. Matching Aerial Images to 3d Building Models Based on Context-Based Geometric Hashing

    NASA Astrophysics Data System (ADS)

    Jung, J.; Bang, K.; Sohn, G.; Armenakis, C.

    2016-06-01

    In this paper, a new model-to-image framework to automatically align a single airborne image with existing 3D building models using geometric hashing is proposed. As a prerequisite process for various applications such as data fusion, object tracking, change detection and texture mapping, the proposed registration method is used for determining accurate exterior orientation parameters (EOPs) of a single image. This model-to-image matching process consists of three steps: 1) feature extraction, 2) similarity measure and matching, and 3) adjustment of EOPs of a single image. For feature extraction, we proposed two types of matching cues, edged corner points representing the saliency of building corner points with associated edges and contextual relations among the edged corner points within an individual roof. These matching features are extracted from both 3D building and a single airborne image. A set of matched corners are found with given proximity measure through geometric hashing and optimal matches are then finally determined by maximizing the matching cost encoding contextual similarity between matching candidates. Final matched corners are used for adjusting EOPs of the single airborne image by the least square method based on co-linearity equations. The result shows that acceptable accuracy of single image's EOP can be achievable by the proposed registration approach as an alternative to labour-intensive manual registration process.

  4. Wavelet-based asphalt concrete texture grading and classification

    NASA Astrophysics Data System (ADS)

    Almuntashri, Ali; Agaian, Sos

    2011-03-01

    In this Paper, we introduce a new method for evaluation, quality control, and automatic grading of texture images representing different textural classes of Asphalt Concrete (AC). Also, we present a new asphalt concrete texture grading, wavelet transform, fractal, and Support Vector Machine (SVM) based automatic classification and recognition system. Experimental results were simulated using different cross-validation techniques and achieved an average classification accuracy of 91.4.0 % in a set of 150 images belonging to five different texture grades.

  5. Fast wavelet based algorithms for linear evolution equations

    NASA Technical Reports Server (NTRS)

    Engquist, Bjorn; Osher, Stanley; Zhong, Sifen

    1992-01-01

    A class was devised of fast wavelet based algorithms for linear evolution equations whose coefficients are time independent. The method draws on the work of Beylkin, Coifman, and Rokhlin which they applied to general Calderon-Zygmund type integral operators. A modification of their idea is applied to linear hyperbolic and parabolic equations, with spatially varying coefficients. A significant speedup over standard methods is obtained when applied to hyperbolic equations in one space dimension and parabolic equations in multidimensions.

  6. Separate Perceptual and Neural Processing of Velocity- and Disparity-Based 3D Motion Signals.

    PubMed

    Joo, Sung Jun; Czuba, Thaddeus B; Cormack, Lawrence K; Huk, Alexander C

    2016-10-19

    Although the visual system uses both velocity- and disparity-based binocular information for computing 3D motion, it is unknown whether (and how) these two signals interact. We found that these two binocular signals are processed distinctly at the levels of both cortical activity in human MT and perception. In human MT, adaptation to both velocity-based and disparity-based 3D motions demonstrated direction-selective neuroimaging responses. However, when adaptation to one cue was probed using the other cue, there was no evidence of interaction between them (i.e., there was no "cross-cue" adaptation). Analogous psychophysical measurements yielded correspondingly weak cross-cue motion aftereffects (MAEs) in the face of very strong within-cue adaptation. In a direct test of perceptual independence, adapting to opposite 3D directions generated by different binocular cues resulted in simultaneous, superimposed, opposite-direction MAEs. These findings suggest that velocity- and disparity-based 3D motion signals may both flow through area MT but constitute distinct signals and pathways.

  7. Plane-based optimization for 3D object reconstruction from single line drawings.

    PubMed

    Liu, Jianzhuang; Cao, Liangliang; Li, Zhenguo; Tang, Xiaoou

    2008-02-01

    In previous optimization-based methods of 3D planar-faced object reconstruction from single 2D line drawings, the missing depths of the vertices of a line drawing (and other parameters in some methods) are used as the variables of the objective functions. A 3D object with planar faces is derived by finding values for these variables that minimize the objective functions. These methods work well for simple objects with a small number N of variables. As N grows, however, it is very difficult for them to find expected objects. This is because with the nonlinear objective functions in a space of large dimension N, the search for optimal solutions can easily get trapped into local minima. In this paper, we use the parameters of the planes that pass through the planar faces of an object as the variables of the objective function. This leads to a set of linear constraints on the planes of the object, resulting in a much lower dimensional nullspace where optimization is easier to achieve. We prove that the dimension of this nullspace is exactly equal to the minimum number of vertex depths which define the 3D object. Since a practical line drawing is usually not an exact projection of a 3D object, we expand the nullspace to a larger space based on the singular value decomposition of the projection matrix of the line drawing. In this space, robust 3D reconstruction can be achieved. Compared with two most related methods, our method not only can reconstruct more complex 3D objects from 2D line drawings, but also is computationally more efficient.

  8. Automatic pole-like object modeling via 3D part-based analysis of point cloud

    NASA Astrophysics Data System (ADS)

    He, Liu; Yang, Haoxiang; Huang, Yuchun

    2016-10-01

    Pole-like objects, including trees, lampposts and traffic signs, are indispensable part of urban infrastructure. With the advance of vehicle-based laser scanning (VLS), massive point cloud of roadside urban areas becomes applied in 3D digital city modeling. Based on the property that different pole-like objects have various canopy parts and similar trunk parts, this paper proposed the 3D part-based shape analysis to robustly extract, identify and model the pole-like objects. The proposed method includes: 3D clustering and recognition of trunks, voxel growing and part-based 3D modeling. After preprocessing, the trunk center is identified as the point that has local density peak and the largest minimum inter-cluster distance. Starting from the trunk centers, the remaining points are iteratively clustered to the same centers of their nearest point with higher density. To eliminate the noisy points, cluster border is refined by trimming boundary outliers. Then, candidate trunks are extracted based on the clustering results in three orthogonal planes by shape analysis. Voxel growing obtains the completed pole-like objects regardless of overlaying. Finally, entire trunk, branch and crown part are analyzed to obtain seven feature parameters. These parameters are utilized to model three parts respectively and get signal part-assembled 3D model. The proposed method is tested using the VLS-based point cloud of Wuhan University, China. The point cloud includes many kinds of trees, lampposts and other pole-like posters under different occlusions and overlaying. Experimental results show that the proposed method can extract the exact attributes and model the roadside pole-like objects efficiently.

  9. JND measurements and wavelet-based image coding

    NASA Astrophysics Data System (ADS)

    Shen, Day-Fann; Yan, Loon-Shan

    1998-06-01

    Two major issues in image coding are the effective incorporation of human visual system (HVS) properties and the effective objective measure for evaluating image quality (OQM). In this paper, we treat the two issues in an integrated fashion. We build a JND model based on the measurements of the JND (Just Noticeable Difference) property of HVS. We found that JND does not only depend on the background intensity but also a function of both spatial frequency and patten direction. Wavelet transform, due to its excellent simultaneous Time (space)/frequency resolution, is the best choice to apply the JND model. We mathematically derive an OQM called JND_PSNR that is based on the JND property and wavelet decomposed subbands. JND_PSNR is more consistent with human perception and is recommended as an alternative to the PSNR or SNR. With the JND_PSNR in mind, we proceed to propose a wavelet and JND based codec called JZW. JZW quantizes coefficients in each subband with proper step size according to the subband's importance to human perception. Many characteristics of JZW are discussed, its performance evaluated and compared with other famous algorithms such as EZW, SPIHT and TCCVQ. Our algorithm has 1 - 1.5 dB gain over SPIHT even when we use simple Huffman coding rather than the more efficient adaptive arithmetic coding.

  10. Low-cost structured-light based 3D capture system design

    NASA Astrophysics Data System (ADS)

    Dong, Jing; Bengtson, Kurt R.; Robinson, Barrett F.; Allebach, Jan P.

    2014-03-01

    Most of the 3D capture products currently in the market are high-end and pricey. They are not targeted for consumers, but rather for research, medical, or industrial usage. Very few aim to provide a solution for home and small business applications. Our goal is to fill in this gap by only using low-cost components to build a 3D capture system that can satisfy the needs of this market segment. In this paper, we present a low-cost 3D capture system based on the structured-light method. The system is built around the HP TopShot LaserJet Pro M275. For our capture device, we use the 8.0 Mpixel camera that is part of the M275. We augment this hardware with two 3M MPro 150 VGA (640 × 480) pocket projectors. We also describe an analytical approach to predicting the achievable resolution of the reconstructed 3D object based on differentials and small signal theory, and an experimental procedure for validating that the system under test meets the specifications for reconstructed object resolution that are predicted by our analytical model. By comparing our experimental measurements from the camera-projector system with the simulation results based on the model for this system, we conclude that our prototype system has been correctly configured and calibrated. We also conclude that with the analytical models, we have an effective means for specifying system parameters to achieve a given target resolution for the reconstructed object.

  11. Model-based risk assessment for motion effects in 3D radiotherapy of lung tumors

    NASA Astrophysics Data System (ADS)

    Werner, René; Ehrhardt, Jan; Schmidt-Richberg, Alexander; Handels, Heinz

    2012-02-01

    Although 4D CT imaging becomes available in an increasing number of radiotherapy facilities, 3D imaging and planning is still standard in current clinical practice. In particular for lung tumors, respiratory motion is a known source of uncertainty and should be accounted for during radiotherapy planning - which is difficult by using only a 3D planning CT. In this contribution, we propose applying a statistical lung motion model to predict patients' motion patterns and to estimate dosimetric motion effects in lung tumor radiotherapy if only 3D images are available. Being generated based on 4D CT images of patients with unimpaired lung motion, the model tends to overestimate lung tumor motion. It therefore promises conservative risk assessment regarding tumor dose coverage. This is exemplarily evaluated using treatment plans of lung tumor patients with different tumor motion patterns and for two treatment modalities (conventional 3D conformal radiotherapy and step-&- shoot intensity modulated radiotherapy). For the test cases, 4D CT images are available. Thus, also a standard registration-based 4D dose calculation is performed, which serves as reference to judge plausibility of the modelbased 4D dose calculation. It will be shown that, if combined with an additional simple patient-specific breathing surrogate measurement (here: spirometry), the model-based dose calculation provides reasonable risk assessment of respiratory motion effects.

  12. Polymer-based mesh as supports for multi-layered 3D cell culture and assays.

    PubMed

    Simon, Karen A; Park, Kyeng Min; Mosadegh, Bobak; Subramaniam, Anand Bala; Mazzeo, Aaron D; Ngo, Philip M; Whitesides, George M

    2014-01-01

    Three-dimensional (3D) culture systems can mimic certain aspects of the cellular microenvironment found in vivo, but generation, analysis and imaging of current model systems for 3D cellular constructs and tissues remain challenging. This work demonstrates a 3D culture system-Cells-in-Gels-in-Mesh (CiGiM)-that uses stacked sheets of polymer-based mesh to support cells embedded in gels to form tissue-like constructs; the stacked sheets can be disassembled by peeling the sheets apart to analyze cultured cells-layer-by-layer-within the construct. The mesh sheets leave openings large enough for light to pass through with minimal scattering, and thus allowing multiple options for analysis-(i) using straightforward analysis by optical light microscopy, (ii) by high-resolution analysis with fluorescence microscopy, or (iii) with a fluorescence gel scanner. The sheets can be patterned into separate zones with paraffin film-based decals, in order to conduct multiple experiments in parallel; the paraffin-based decal films also block lateral diffusion of oxygen effectively. CiGiM simplifies the generation and analysis of 3D culture without compromising throughput, and quality of the data collected: it is especially useful in experiments that require control of oxygen levels, and isolation of adjacent wells in a multi-zone format.

  13. Inertial Sensor-Based Touch and Shake Metaphor for Expressive Control of 3D Virtual Avatars.

    PubMed

    Patil, Shashidhar; Chintalapalli, Harinadha Reddy; Kim, Dubeom; Chai, Youngho

    2015-06-18

    In this paper, we present an inertial sensor-based touch and shake metaphor for expressive control of a 3D virtual avatar in a virtual environment. An intuitive six degrees-of-freedom wireless inertial motion sensor is used as a gesture and motion control input device with a sensor fusion algorithm. The algorithm enables user hand motions to be tracked in 3D space via magnetic, angular rate, and gravity sensors. A quaternion-based complementary filter is implemented to reduce noise and drift. An algorithm based on dynamic time-warping is developed for efficient recognition of dynamic hand gestures with real-time automatic hand gesture segmentation. Our approach enables the recognition of gestures and estimates gesture variations for continuous interaction. We demonstrate the gesture expressivity using an interactive flexible gesture mapping interface for authoring and controlling a 3D virtual avatar and its motion by tracking user dynamic hand gestures. This synthesizes stylistic variations in a 3D virtual avatar, producing motions that are not present in the motion database using hand gesture sequences from a single inertial motion sensor.

  14. Obstacle classification and 3D measurement in unstructured environments based on ToF cameras.

    PubMed

    Yu, Hongshan; Zhu, Jiang; Wang, Yaonan; Jia, Wenyan; Sun, Mingui; Tang, Yandong

    2014-06-18

    Inspired by the human 3D visual perception system, we present an obstacle detection and classification method based on the use of Time-of-Flight (ToF) cameras for robotic navigation in unstructured environments. The ToF camera provides 3D sensing by capturing an image along with per-pixel 3D space information. Based on this valuable feature and human knowledge of navigation, the proposed method first removes irrelevant regions which do not affect robot's movement from the scene. In the second step, regions of interest are detected and clustered as possible obstacles using both 3D information and intensity image obtained by the ToF camera. Consequently, a multiple relevance vector machine (RVM) classifier is designed to classify obstacles into four possible classes based on the terrain traversability and geometrical features of the obstacles. Finally, experimental results in various unstructured environments are presented to verify the robustness and performance of the proposed approach. We have found that, compared with the existing obstacle recognition methods, the new approach is more accurate and efficient.

  15. Inertial Sensor-Based Touch and Shake Metaphor for Expressive Control of 3D Virtual Avatars

    PubMed Central

    Patil, Shashidhar; Chintalapalli, Harinadha Reddy; Kim, Dubeom; Chai, Youngho

    2015-01-01

    In this paper, we present an inertial sensor-based touch and shake metaphor for expressive control of a 3D virtual avatar in a virtual environment. An intuitive six degrees-of-freedom wireless inertial motion sensor is used as a gesture and motion control input device with a sensor fusion algorithm. The algorithm enables user hand motions to be tracked in 3D space via magnetic, angular rate, and gravity sensors. A quaternion-based complementary filter is implemented to reduce noise and drift. An algorithm based on dynamic time-warping is developed for efficient recognition of dynamic hand gestures with real-time automatic hand gesture segmentation. Our approach enables the recognition of gestures and estimates gesture variations for continuous interaction. We demonstrate the gesture expressivity using an interactive flexible gesture mapping interface for authoring and controlling a 3D virtual avatar and its motion by tracking user dynamic hand gestures. This synthesizes stylistic variations in a 3D virtual avatar, producing motions that are not present in the motion database using hand gesture sequences from a single inertial motion sensor. PMID:26094629

  16. Multi-Modal Clique-Graph Matching for View-Based 3D Model Retrieval.

    PubMed

    Liu, An-An; Nie, Wei-Zhi; Gao, Yue; Su, Yu-Ting

    2016-05-01

    Multi-view matching is an important but a challenging task in view-based 3D model retrieval. To address this challenge, we propose an original multi-modal clique graph (MCG) matching method in this paper. We systematically present a method for MCG generation that is composed of cliques, which consist of neighbor nodes in multi-modal feature space and hyper-edges that link pairwise cliques. Moreover, we propose an image set-based clique/edgewise similarity measure to address the issue of the set-to-set distance measure, which is the core problem in MCG matching. The proposed MCG provides the following benefits: 1) preserves the local and global attributes of a graph with the designed structure; 2) eliminates redundant and noisy information by strengthening inliers while suppressing outliers; and 3) avoids the difficulty of defining high-order attributes and solving hyper-graph matching. We validate the MCG-based 3D model retrieval using three popular single-modal data sets and one novel multi-modal data set. Extensive experiments show the superiority of the proposed method through comparisons. Moreover, we contribute a novel real-world 3D object data set, the multi-view RGB-D object data set. To the best of our knowledge, it is the largest real-world 3D object data set containing multi-modal and multi-view information.

  17. vPresent: A cloud based 3D virtual presentation environment for interactive product customization

    NASA Astrophysics Data System (ADS)

    Nan, Xiaoming; Guo, Fei; He, Yifeng; Guan, Ling

    2013-09-01

    In modern society, many companies offer product customization services to their customers. There are two major issues in providing customized products. First, product manufacturers need to effectively present their products to the customers who may be located in any geographical area. Second, customers need to be able to provide their feedbacks on the product in real-time. However, the traditional presentation approaches cannot effectively convey sufficient information for the product or efficiently adjust product design according to customers' real-time feedbacks. In order to address these issues, we propose vPresent , a cloud based 3D virtual presentation environment, in this paper. In vPresent, the product expert can show the 3D virtual product to the remote customers and dynamically customize the product based on customers' feedbacks, while customers can provide their opinions in real time when they are viewing a vivid 3D visualization of the product. Since the proposed vPresent is a cloud based system, the customers are able to access the customized virtual products from anywhere at any time, via desktop, laptop, or even smart phone. The proposed vPresent is expected to effectively deliver 3D visual information to customers and provide an interactive design platform for the development of customized products.

  18. Controllable 3D Display System Based on Frontal Projection Lenticular Screen

    NASA Astrophysics Data System (ADS)

    Feng, Q.; Sang, X.; Yu, X.; Gao, X.; Wang, P.; Li, C.; Zhao, T.

    2014-08-01

    A novel auto-stereoscopic three-dimensional (3D) projection display system based on the frontal projection lenticular screen is demonstrated. It can provide high real 3D experiences and the freedom of interaction. In the demonstrated system, the content can be changed and the dense of viewing points can be freely adjusted according to the viewers' demand. The high dense viewing points can provide smooth motion parallax and larger image depth without blurry. The basic principle of stereoscopic display is described firstly. Then, design architectures including hardware and software are demonstrated. The system consists of a frontal projection lenticular screen, an optimally designed projector-array and a set of multi-channel image processors. The parameters of the frontal projection lenticular screen are based on the demand of viewing such as the viewing distance and the width of view zones. Each projector is arranged on an adjustable platform. The set of multi-channel image processors are made up of six PCs. One of them is used as the main controller, the other five client PCs can process 30 channel signals and transmit them to the projector-array. Then a natural 3D scene will be perceived based on the frontal projection lenticular screen with more than 1.5 m image depth in real time. The control section is presented in detail, including parallax adjustment, system synchronization, distortion correction, etc. Experimental results demonstrate the effectiveness of this novel controllable 3D display system.

  19. Polymer-Based Mesh as Supports for Multi-layered 3D Cell Culture and Assays

    PubMed Central

    Simon, Karen A.; Park, Kyeng Min; Mosadegh, Bobak; Subramaniam, Anand Bala; Mazzeo, Aaron; Ngo, Phil M.; Whitesides, George M.

    2013-01-01

    Three-dimensional (3D) culture systems can mimic certain aspects of the cellular microenvironment found in vivo, but generation, analysis and imaging of current model systems for 3D cellular constructs and tissues remain challenging. This work demonstrates a 3D culture system – Cells-in-Gels-in-Mesh (CiGiM) – that uses stacked sheets of polymer-based mesh to support cells embedded in gels to form tissue-like constructs; the stacked sheets can be disassembled by peeling the sheets apart to analyze cultured cells—layer-by-layer—within the construct. The mesh sheets leave openings large enough for light to pass through with minimal scattering, and thus allowing multiple options for analysis—(i) using straightforward analysis by optical light microscopy, (ii) by high-resolution analysis with fluorescence microscopy, or (iii) with a fluorescence gel scanner. The sheets can be patterned into separate zones with paraffin film-based decals, in order to conduct multiple experiments in parallel; the paraffin-based decal films also block lateral diffusion of oxygen effectively. CiGiM simplifies the generation and analysis of 3D culture without compromising throughput, and quality of the data collected: it is especially useful in experiments that require control of oxygen levels, and isolation of adjacent wells in a multi-zone format. PMID:24095253

  20. Obstacle Classification and 3D Measurement in Unstructured Environments Based on ToF Cameras

    PubMed Central

    Yu, Hongshan; Zhu, Jiang; Wang, Yaonan; Jia, Wenyan; Sun, Mingui; Tang, Yandong

    2014-01-01

    Inspired by the human 3D visual perception system, we present an obstacle detection and classification method based on the use of Time-of-Flight (ToF) cameras for robotic navigation in unstructured environments. The ToF camera provides 3D sensing by capturing an image along with per-pixel 3D space information. Based on this valuable feature and human knowledge of navigation, the proposed method first removes irrelevant regions which do not affect robot's movement from the scene. In the second step, regions of interest are detected and clustered as possible obstacles using both 3D information and intensity image obtained by the ToF camera. Consequently, a multiple relevance vector machine (RVM) classifier is designed to classify obstacles into four possible classes based on the terrain traversability and geometrical features of the obstacles. Finally, experimental results in various unstructured environments are presented to verify the robustness and performance of the proposed approach. We have found that, compared with the existing obstacle recognition methods, the new approach is more accurate and efficient. PMID:24945679

  1. Image-Based Modeling Techniques for Architectural Heritage 3d Digitalization: Limits and Potentialities

    NASA Astrophysics Data System (ADS)

    Santagati, C.; Inzerillo, L.; Di Paola, F.

    2013-07-01

    3D reconstruction from images has undergone a revolution in the last few years. Computer vision techniques use photographs from data set collection to rapidly build detailed 3D models. The simultaneous applications of different algorithms (MVS), the different techniques of image matching, feature extracting and mesh optimization are inside an active field of research in computer vision. The results are promising: the obtained models are beginning to challenge the precision of laser-based reconstructions. Among all the possibilities we can mainly distinguish desktop and web-based packages. Those last ones offer the opportunity to exploit the power of cloud computing in order to carry out a semi-automatic data processing, thus allowing the user to fulfill other tasks on its computer; whereas desktop systems employ too much processing time and hard heavy approaches. Computer vision researchers have explored many applications to verify the visual accuracy of 3D model but the approaches to verify metric accuracy are few and no one is on Autodesk 123D Catch applied on Architectural Heritage Documentation. Our approach to this challenging problem is to compare the 3Dmodels by Autodesk 123D Catch and 3D models by terrestrial LIDAR considering different object size, from the detail (capitals, moldings, bases) to large scale buildings for practitioner purpose.

  2. Compression of Ultrasonic NDT Image by Wavelet Based Local Quantization

    NASA Astrophysics Data System (ADS)

    Cheng, W.; Li, L. Q.; Tsukada, K.; Hanasaki, K.

    2004-02-01

    Compression on ultrasonic image that is always corrupted by noise will cause `over-smoothness' or much distortion. To solve this problem to meet the need of real time inspection and tele-inspection, a compression method based on Discrete Wavelet Transform (DWT) that can also suppress the noise without losing much flaw-relevant information, is presented in this work. Exploiting the multi-resolution and interscale correlation property of DWT, a simple way named DWCs classification, is introduced first to classify detail wavelet coefficients (DWCs) as dominated by noise, signal or bi-effected. A better denoising can be realized by selective thresholding DWCs. While in `Local quantization', different quantization strategies are applied to the DWCs according to their classification and the local image property. It allocates the bit rate more efficiently to the DWCs thus achieve a higher compression rate. Meanwhile, the decompressed image shows the effects of noise suppressed and flaw characters preserved.

  3. Ground extraction from airborne laser data based on wavelet analysis

    NASA Astrophysics Data System (ADS)

    Xu, Liang; Yang, Yan; Jiang, Bowen; Li, Jia

    2007-11-01

    With the advantages of high resolution and accuracy, airborne laser scanning data are widely used in topographic mapping. In order to generate a DTM, measurements from object features such as buildings, vehicles and vegetation have to be classified and removed. However, the automatic extraction of bare earth from point clouds acquired by airborne laser scanning equipment remains a problem in LIDAR data filtering nowadays. In this paper, a filter algorithm based on wavelet analysis is proposed. Relying on the capability of detecting discontinuities of continuous wavelet transform and the feature of multi-resolution analysis, the object points can be removed, while ground data are preserved. In order to evaluate the performance of this approach, we applied it to the data set used in the ISPRS filter test in 2003. 15 samples have been tested by the proposed approach. Results showed that it filtered most of the objects like vegetation and buildings, and extracted a well defined ground model.

  4. Wavelet-based zerotree coding of aerospace images

    NASA Astrophysics Data System (ADS)

    Franques, Victoria T.; Jain, Vijay K.

    1996-06-01

    This paper presents a wavelet based image coding method achieving high levels of compression. A multi-resolution subband decomposition system is constructed using Quadrature Mirror Filters. Symmetric extension and windowing of the multi-scaled subbands are incorporated to minimize the boundary effects. Next, the Embedded Zerotree Wavelet coding algorithm is used for data compression method. Elimination of the isolated zero symbol, for certain subbands, leads to an improved EZW algorithm. Further compression is obtained with an adaptive arithmetic coder. We achieve a PSNR of 26.91 dB at a bit rate of 0.018, 35.59 dB at a bit rate of 0.149, and 43.05 dB at 0.892 bits/pixel for the aerospace image, Refuel.

  5. A wavelet watermarking algorithm based on a tree structure

    NASA Astrophysics Data System (ADS)

    Guitart Pla, Oriol; Lin, Eugene T.; Delp, Edward J., III

    2004-06-01

    We describe a blind watermarking technique for digital images. Our technique constructs an image-dependent watermark in the discrete wavelet transform (DWT) domain and inserts the watermark in the most signifcant coefficients of the image. The watermarked coefficients are determined by using the hierarchical tree structure induced by the DWT, similar in concept to embedded zerotree wavelet (EZW) compression. If the watermarked image is attacked or manipulated such that the set of significant coefficients is changed, the tree structure allows the correlation-based watermark detector to recover synchronization. Our technique also uses a visual adaptive scheme to insert the watermark to minimize watermark perceptibility. The visual adaptive scheme also takes advantage of the tree structure. Finally, a template is inserted into the watermark to provide robustness against geometric attacks. The template detection uses the cross-ratio of four collinear points.

  6. Health monitoring of cooling fan bearings based on wavelet filter

    NASA Astrophysics Data System (ADS)

    He, Wei; Miao, Qiang; Azarian, Michael; Pecht, Michael

    2015-12-01

    In this paper, a vibration-based health monitoring approach for cooling fans is proposed using a wavelet filter for early detection of faults in fan bearings and for the assessment of fault severity. To match the wavelet filter to the fault characteristic signal, a fuzzy rule is introduced to maximize the amplitudes of bearing characteristic frequencies (BCFs), which are an indicator of bearing faults. The sum of the amplitudes of BCFs and their harmonics (SABCF) is used as an index to capture the bearing degradation trend. A comparative study is conducted with commonly used time-domain indices in the degradation assessment, and performance is quantified by three measures, i.e., monotonicity, prognosability, and trendability. The analysis results of the experimental data show that the proposed method can effectively detect incipient defects and can better capture the degradation trend of fan bearings than traditional time-domain indices in vibration analysis.

  7. Proper orthogonal decomposition and wavelet methods for noise reduction in particle-based transport calculations

    NASA Astrophysics Data System (ADS)

    Nguyen van Ye, Romain; Del-Castillo-Negrete, Diego; Spong, D.; Hirshman, S.; Farge, M.

    2008-11-01

    A limitation of particle-based transport calculations is the noise due to limited statistical sampling. Thus, a key element for the success of these calculations is the development of efficient denoising methods. Here we discuss denoising techniques based on Proper Orthogonal Decomposition (POD) and Wavelet Decomposition (WD). The goal is the reconstruction of smooth (denoised) particle distribution functions from discrete particle data obtained from Monte Carlo simulations. In 2-D, the POD method is based on low rank truncations of the singular value decomposition of the data. For 3-D we propose the use of a generalized low rank approximation of matrices technique. The WD denoising is based on the thresholding of empirical wavelet coefficients [Donoho et al., 1996]. The methods are illustrated and tested with Monte-Carlo particle simulation data of plasma collisional relaxation including pitch angle and energy scattering. As an application we consider guiding-center transport with collisions in a magnetically confined plasma in toroidal geometry. The proposed noise reduction methods allow to achieve high levels of smoothness in the particle distribution function using significantly less particles in the computations.

  8. 3D MRI-based tumor delineation of ocular melanoma and its comparison with conventional techniques

    SciTech Connect

    Daftari, Inder k; Aghaian, Elsa; O'Brien, Joan M.; Dillon, William; Phillips, Theodore L.

    2005-11-15

    The aim of this study is to (1) compare the delineation of the tumor volume for ocular melanoma on high-resolution three-dimensional (3D) T2-weighted fast spin echo magnetic resonance imaging (MRI) images with conventional techniques of A- and B-scan ultrasound, transcleral illumination, and placement of tantalum markers around tumor base and (2) to evaluate whether the surgically placed marker ring tumor delineation can be replaced by 3D MRI based tumor delineation. High-resolution 3D T2-weighted fast spin echo (3D FSE) MRI scans were obtained for 60 consecutive ocular melanoma patients using a 1.5 T MRI (GE Medical Systems, Milwaukee, WI), in a standard head coil. These patients were subsequently treated with proton beam therapy at the UC Davis Cyclotron, Davis, CA. The tumor was delineated by placement of tantalum rings (radio-opaque markers) around the tumor periphery as defined by pupillary transillumination during surgery. A point light source, placed against the sclera, was also used to confirm ring agreement with indirect ophthalmoscopy. When necessary, intraoperative ultrasound was also performed. The patients were planned using EYEPLAN software and the tumor volumes were obtained. For analysis, the tumors were divided into four categories based on tumor height and basal diameter. In order to assess the impact of high-resolution 3D T2 FSE MRI, the tumor volumes were outlined on the MRI scans by two independent observers and the tumor volumes calculated for each patient. Six (10%) of 60 patients had tumors, which were not visible on 3D MRI images. These six patients had tumors with tumor heights {<=}3 mm. A small intraobserver variation with a mean of (-0.22{+-}4)% was seen in tumor volumes delineated by 3D T2 FSE MR images. The ratio of tumor volumes measured on MRI to EYEPLAN for the largest to the smallest tumor volumes varied between 0.993 and 1.02 for 54 patients. The tumor volumes measured directly on 3D T2 FSE MRI ranged from 4.03 to 0.075 cm{sup 3

  9. 3D MRI-based tumor delineation of ocular melanoma and its comparison with conventional techniques.

    PubMed

    Daftari, Inder k; Aghaian, Elsa; O'Brien, Joan M; Dillon, William; Phillips, Theodore L

    2005-11-01

    The aim of this study is to (1) compare the delineation of the tumor volume for ocular melanoma on high-resolution three-dimensional (3D) T2-weighted fast spin echo magnetic resonance imaging (MRI) images with conventional techniques of A- and B-scan ultrasound, transcleral illumination, and placement of tantalum markers around tumor base and (2) to evaluate whether the surgically placed marker ring tumor delineation can be replaced by 3D MRI based tumor delineation. High-resolution 3D T2-weighted fast spin echo (3D FSE) MRI scans were obtained for 60 consecutive ocular melanoma patients using a 1.5 T MRI (GE Medical Systems, Milwaukee, WI), in a standard head coil. These patients were subsequently treated with proton beam therapy at the UC Davis Cyclotron, Davis, CA. The tumor was delineated by placement of tantalum rings (radio-opaque markers) around the tumor periphery as defined by pupillary transillumination during surgery. A point light source, placed against the sclera, was also used to confirm ring agreement with indirect ophthalmoscopy. When necessary, intraoperative ultrasound was also performed. The patients were planned using EYEPLAN software and the tumor volumes were obtained. For analysis, the tumors were divided into four categories based on tumor height and basal diameter. In order to assess the impact of high-resolution 3D T2 FSE MRI, the tumor volumes were outlined on the MRI scans by two independent observers and the tumor volumes calculated for each patient. Six (10%) of 60 patients had tumors, which were not visible on 3D MRI images. These six patients had tumors with tumor heights < or = 3 mm. A small intraobserver variation with a mean of (-0.22 +/- 4)% was seen in tumor volumes delineated by 3D T2 FSE MR images. The ratio of tumor volumes measured on MRI to EYEPLAN for the largest to the smallest tumor volumes varied between 0.993 and 1.02 for 54 patients. The tumor volumes measured directly on 3D T2 FSE MRI ranged from 4.03 to 0.075 cm3

  10. Generalized Hough transform based time invariant action recognition with 3D pose information

    NASA Astrophysics Data System (ADS)

    Muench, David; Huebner, Wolfgang; Arens, Michael

    2014-10-01

    Human action recognition has emerged as an important field in the computer vision community due to its large number of applications such as automatic video surveillance, content based video-search and human robot interaction. In order to cope with the challenges that this large variety of applications present, recent research has focused more on developing classifiers able to detect several actions in more natural and unconstrained video sequences. The invariance discrimination tradeoff in action recognition has been addressed by utilizing a Generalized Hough Transform. As a basis for action representation we transform 3D poses into a robust feature space, referred to as pose descriptors. For each action class a one-dimensional temporal voting space is constructed. Votes are generated from associating pose descriptors with their position in time relative to the end of an action sequence. Training data consists of manually segmented action sequences. In the detection phase valid human 3D poses are assumed as input, e.g. originating from 3D sensors or monocular pose reconstruction methods. The human 3D poses are normalized to gain view-independence and transformed into (i) relative limb-angle space to ensure independence of non-adjacent joints or (ii) geometric features. In (i) an action descriptor consists of the relative angles between limbs and their temporal derivatives. In (ii) the action descriptor consists of different geometric features. In order to circumvent the problem of time-warping we propose to use a codebook of prototypical 3D poses which is generated from sample sequences of 3D motion capture data. This idea is in accordance with the concept of equivalence classes in action space. Results of the codebook method are presented using the Kinect sensor and the CMU Motion Capture Database.

  11. Adaptive directional lifting-based wavelet transform for image coding.

    PubMed

    Ding, Wenpeng; Wu, Feng; Wu, Xiaolin; Li, Shipeng; Li, Houqiang

    2007-02-01

    We present a novel 2-D wavelet transform scheme of adaptive directional lifting (ADL) in image coding. Instead of alternately applying horizontal and vertical lifting, as in present practice, ADL performs lifting-based prediction in local windows in the direction of high pixel correlation. Hence, it adapts far better to the image orientation features in local windows. The ADL transform is achieved by existing 1-D wavelets and is seamlessly integrated into the global wavelet transform. The predicting and updating signals of ADL can be derived even at the fractional pixel precision level to achieve high directional resolution, while still maintaining perfect reconstruction. To enhance the ADL performance, a rate-distortion optimized directional segmentation scheme is also proposed to form and code a hierarchical image partition adapting to local features. Experimental results show that the proposed ADL-based image coding technique outperforms JPEG 2000 in both PSNR and visual quality, with the improvement up to 2.0 dB on images with rich orientation features.

  12. Registration of 3D spectral OCT volumes combining ICP with a graph-based approach

    NASA Astrophysics Data System (ADS)

    Niemeijer, Meindert; Lee, Kyungmoo; Garvin, Mona K.; Abràmoff, Michael D.; Sonka, Milan

    2012-02-01

    The introduction of spectral Optical Coherence Tomography (OCT) scanners has enabled acquisition of high resolution, 3D cross-sectional volumetric images of the retina. 3D-OCT is used to detect and manage eye diseases such as glaucoma and age-related macular degeneration. To follow-up patients over time, image registration is a vital tool to enable more precise, quantitative comparison of disease states. In this work we present a 3D registrationmethod based on a two-step approach. In the first step we register both scans in the XY domain using an Iterative Closest Point (ICP) based algorithm. This algorithm is applied to vessel segmentations obtained from the projection image of each scan. The distance minimized in the ICP algorithm includes measurements of the vessel orientation and vessel width to allow for a more robust match. In the second step, a graph-based method is applied to find the optimal translation along the depth axis of the individual A-scans in the volume to match both scans. The cost image used to construct the graph is based on the mean squared error (MSE) between matching A-scans in both images at different translations. We have applied this method to the registration of Optic Nerve Head (ONH) centered 3D-OCT scans of the same patient. First, 10 3D-OCT scans of 5 eyes with glaucoma imaged in vivo were registered for a qualitative evaluation of the algorithm performance. Then, 17 OCT data set pairs of 17 eyes with known deformation were used for quantitative assessment of the method's robustness.

  13. Discrimination of walking patterns using wavelet-based fractal analysis.

    PubMed

    Sekine, Masaki; Tamura, Toshiyo; Akay, Metin; Fujimoto, Toshiro; Togawa, Tatsuo; Fukui, Yasuhiro

    2002-09-01

    In this paper, we attempted to classify the acceleration signals for walking along a corridor and on stairs by using the wavelet-based fractal analysis method. In addition, the wavelet-based fractal analysis method was used to evaluate the gait of elderly subjects and patients with Parkinson's disease. The triaxial acceleration signals were measured close to the center of gravity of the body while the subject walked along a corridor and up and down stairs continuously. Signal measurements were recorded from 10 healthy young subjects and 11 elderly subjects. For comparison, two patients with Parkinson's disease participated in the level walking. The acceleration signal in each direction was decomposed to seven detailed signals at different wavelet scales by using the discrete wavelet transform. The variances of detailed signals at scales 7 to 1 were calculated. The fractal dimension of the acceleration signal was then estimated from the slope of the variance progression. The fractal dimensions were significantly different among the three types of walking for individual subjects (p < 0.01) and showed a high reproducibility. Our results suggest that the fractal dimensions are effective for classifying the walking types. Moreover, the fractal dimensions were significantly higher for the elderly subjects than for the young subjects (p < 0.01). For the patients with Parkinson's disease, the fractal dimensions tended to be higher than those of healthy subjects. These results suggest that the acceleration signals change into a more complex pattern with aging and with Parkinson's disease, and the fractal dimension can be used to evaluate the gait of elderly subjects and patients with Parkinson's disease.

  14. FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Szadkowski, Zbigniew; Szadkowska, Anna

    2014-12-01

    Experiments which show coherent radio emission from extensive air showers induced by ultra-high-energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100 % up time as, e.g., surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g., the Pierre Auger Observatory) as another type of air-shower detector in addition to fluorescence detectors, which operate with only ˜10 % of duty on dark nights. The radio signals from air showers are caused by coherent emission from geomagnetic radiation and charge-excess processes. The self-triggers in radio detectors currently in use often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data require significant manpower for off-line analysis. Improvement of trigger efficiency is a relevant factor. The wavelet trigger, which investigates on-line the power of radio signals (˜ V2/ R), is promising; however, it requires some improvements with respect to current designs. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not originate from cosmic ray showers but could be the result of human contamination. The engine of the wavelet analysis can be implemented in the modern powerful FPGAs and can remove suspicious events on-line to reduce the trigger rate.

  15. 2D versus 3D cross-correlation-based radial and circumferential strain estimation using multiplane 2D ultrafast ultrasound in a 3D atherosclerotic carotid artery model.

    PubMed

    Fekkes, Stein; Swillens, Abigail E S; Hansen, Hendrik H G; Saris, Anne E C M; Nillesen, Maartje M; Iannaccone, Francesco; Segers, Patrick; de Korte, Chris L

    2016-08-25

    Three-dimensional strain estimation might improve the detection and localization of high strain regions in the carotid artery for identification of vulnerable plaques. This study compares 2D vs. 3D displacement estimation in terms of radial and circumferential strain using simulated ultrasound images of a patient specific 3D atherosclerotic carotid artery model at the bifurcation embedded in surrounding tissue generated with ABAQUS software. Global longitudinal motion was superimposed to the model based on literature data. A Philips L11-3 linear array transducer was simulated which transmitted plane waves at 3 alternating angles at a pulse repetition rate of 10 kHz. Inter-frame radiofrequency ultrasound data were simulated in Field II for 191 equally spaced longitudinal positions of the internal carotid artery. Accumulated radial and circumferential displacements were estimated using tracking of the inter-frame displacements estimated by a two-step normalized cross-correlation method and displacement compounding. Least squares strain estimation was performed to determine accumulated radial and circumferential strain. The performance of the 2D and 3D method was compared by calculating the root-mean-squared error of the estimated strains with respect to the reference strains obtained from the model. More accurate strain images were obtained using the 3D displacement estimation for the entire cardiac cycle. The 3D technique clearly outperformed the 2D technique in phases with high inter-frame longitudinal motion. In fact the large inter-frame longitudinal motion rendered it impossible to accurately track the tissue and cumulate strains over the entire cardiac cycle with the 2D technique.

  16. 3D reconstructions with pixel-based images are made possible by digitally clearing plant and animal tissue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reconstruction of 3D images from a series of 2D images has been restricted by the limited capacity to decrease the opacity of surrounding tissue. Commercial software that allows color-keying and manipulation of 2D images in true 3D space allowed us to produce 3D reconstructions from pixel based imag...

  17. Image-Based Airborne LiDAR Point Cloud Encoding for 3d Building Model Retrieval

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Chen; Lin, Chao-Hung

    2016-06-01

    With the development of Web 2.0 and cyber city modeling, an increasing number of 3D models have been available on web-based model-sharing platforms with many applications such as navigation, urban planning, and virtual reality. Based on the concept of data reuse, a 3D model retrieval system is proposed to retrieve building models similar to a user-specified query. The basic idea behind this system is to reuse these existing 3D building models instead of reconstruction from point clouds. To efficiently retrieve models, the models in databases are compactly encoded by using a shape descriptor generally. However, most of the geometric descriptors in related works are applied to polygonal models. In this study, the input query of the model retrieval system is a point cloud acquired by Light Detection and Ranging (LiDAR) systems because of the efficient scene scanning and spatial information collection. Using Point clouds with sparse, noisy, and incomplete sampling as input queries is more difficult than that by using 3D models. Because that the building roof is more informative than other parts in the airborne LiDAR point cloud, an image-based approach is proposed to encode both point clouds from input queries and 3D models in databases. The main goal of data encoding is that the models in the database and input point clouds can be consistently encoded. Firstly, top-view depth images of buildings are generated to represent the geometry surface of a building roof. Secondly, geometric features are extracted from depth images based on height, edge and plane of building. Finally, descriptors can be extracted by spatial histograms and used in 3D model retrieval system. For data retrieval, the models are retrieved by matching the encoding coefficients of point clouds and building models. In experiments, a database including about 900,000 3D models collected from the Internet is used for evaluation of data retrieval. The results of the proposed method show a clear superiority

  18. Progressive Transmission of 3D Building Models based on String Grammars and Planar Half-Spaces

    NASA Astrophysics Data System (ADS)

    Kada, M.

    2014-11-01

    As there are numerous applications for 3D city models with a wide range of model requirements regarding geometric accuracy and granularity, there is also a high demand for such models at different levels of detail (LOD). And although their reconstruction and cartographic generalization has been widely studied, particularly with regard to 3D building models, their encoding for a progressive storage and transmission is up to now not profoundly explored and sufficiently solved. Most often building models at different LODs are considered as discrete entities that are not related to each other. In this paper we present a progressive encoding and transmission scheme for 3D building models that is easy to understand and implement for the end user as well as flexible and extensible for the model producer. The progressive scheme is based on string grammars and describes a sequence of successive LODs as a dynamic set of production rules. In order to restrict the effects of LOD changes on a local range of the progressive string representation, we use a solid modelling approach based on planar half-spaces to construct 3D buildings. The generation of such progressive string grammars is shown and examples are given.

  19. Assessment of eye fatigue caused by 3D displays based on multimodal measurements.

    PubMed

    Bang, Jae Won; Heo, Hwan; Choi, Jong-Suk; Park, Kang Ryoung

    2014-09-04

    With the development of 3D displays, user's eye fatigue has been an important issue when viewing these displays. There have been previous studies conducted on eye fatigue related to 3D display use, however, most of these have employed a limited number of modalities for measurements, such as electroencephalograms (EEGs), biomedical signals, and eye responses. In this paper, we propose a new assessment of eye fatigue related to 3D display use based on multimodal measurements. compared to previous works Our research is novel in the following four ways: first, to enhance the accuracy of assessment of eye fatigue, we measure EEG signals, eye blinking rate (BR), facial temperature (FT), and a subjective evaluation (SE) score before and after a user watches a 3D display; second, in order to accurately measure BR in a manner that is convenient for the user, we implement a remote gaze-tracking system using a high speed (mega-pixel) camera that measures eye blinks of both eyes; thirdly, changes in the FT are measured using a remote thermal camera, which can enhance the measurement of eye fatigue, and fourth, we perform various statistical analyses to evaluate the correlation between the EEG signal, eye BR, FT, and the SE score based on the T-test, correlation matrix, and effect size. Results show that the correlation of the SE with other data (FT, BR, and EEG) is the highest, while those of the FT, BR, and EEG with other data are second, third, and fourth highest, respectively.

  20. Triangular mesh establishment of 3D laser scanning data based on ellipsoidal projection

    NASA Astrophysics Data System (ADS)

    Zheng, De-hua; Xu, Jia; Li, Jia; Wang, Xin-sen

    2011-10-01

    The establishment of high quality triangular mesh is one of the key steps in 3D laser scanning data processing. Traditional triangulation algorithms have been proposed directly on the basis of adjacency relation between points in 3D space. However, when the point density is non-uniform or the noise exists, the problems such as surface hole, dough sheet overlapping and inconsistent normal appear easily. In this paper, a triangular mesh establishing algorithm based on ellipsoidal projection is proposed. After comparing the theory of ellipsoidal projection and cylindrical projection, the proposed triangular mesh establishing algorithm is analyzed in detail including basic idea and implementation method. To evaluate the performance and efficiency of the proposed algorithm, two experiments are then carried out on the 3D point cloud data of a foundation pit. The results indicate that though the computational efficiency of proposed algorithm is a little inferior to the algorithm based on cylindrical projection, the proposed algorithm is more effective for establishing point cloud of both top and bottom of the object and the original topological relation of 3D scanning points can be maintained better.

  1. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation

    NASA Astrophysics Data System (ADS)

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-03-01

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images.

  2. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation

    PubMed Central

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-01-01

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images. PMID:26980176

  3. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation.

    PubMed

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-03-16

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images.

  4. A 3D Model Based Imdoor Navigation System for Hubei Provincial Museum

    NASA Astrophysics Data System (ADS)

    Xu, W.; Kruminaite, M.; Onrust, B.; Liu, H.; Xiong, Q.; Zlatanova, S.

    2013-11-01

    3D models are more powerful than 2D maps for indoor navigation in a complicate space like Hubei Provincial Museum because they can provide accurate descriptions of locations of indoor objects (e.g., doors, windows, tables) and context information of these objects. In addition, the 3D model is the preferred navigation environment by the user according to the survey. Therefore a 3D model based indoor navigation system is developed for Hubei Provincial Museum to guide the visitors of museum. The system consists of three layers: application, web service and navigation, which is built to support localization, navigation and visualization functions of the system. There are three main strengths of this system: it stores all data needed in one database and processes most calculations on the webserver which make the mobile client very lightweight, the network used for navigation is extracted semi-automatically and renewable, the graphic user interface (GUI), which is based on a game engine, has high performance of visualizing 3D model on a mobile display.

  5. Probabilistic Neighborhood-Based Data Collection Algorithms for 3D Underwater Acoustic Sensor Networks

    PubMed Central

    Han, Guangjie; Li, Shanshan; Zhu, Chunsheng; Jiang, Jinfang; Zhang, Wenbo

    2017-01-01

    Marine environmental monitoring provides crucial information and support for the exploitation, utilization, and protection of marine resources. With the rapid development of information technology, the development of three-dimensional underwater acoustic sensor networks (3D UASNs) provides a novel strategy to acquire marine environment information conveniently, efficiently and accurately. However, the specific propagation effects of acoustic communication channel lead to decreased successful information delivery probability with increased distance. Therefore, we investigate two probabilistic neighborhood-based data collection algorithms for 3D UASNs which are based on a probabilistic acoustic communication model instead of the traditional deterministic acoustic communication model. An autonomous underwater vehicle (AUV) is employed to traverse along the designed path to collect data from neighborhoods. For 3D UASNs without prior deployment knowledge, partitioning the network into grids can allow the AUV to visit the central location of each grid for data collection. For 3D UASNs in which the deployment knowledge is known in advance, the AUV only needs to visit several selected locations by constructing a minimum probabilistic neighborhood covering set to reduce data latency. Otherwise, by increasing the transmission rounds, our proposed algorithms can provide a tradeoff between data collection latency and information gain. These algorithms are compared with basic Nearest-neighbor Heuristic algorithm via simulations. Simulation analyses show that our proposed algorithms can efficiently reduce the average data collection completion time, corresponding to a decrease of data latency. PMID:28208735

  6. Probabilistic Neighborhood-Based Data Collection Algorithms for 3D Underwater Acoustic Sensor Networks.

    PubMed

    Han, Guangjie; Li, Shanshan; Zhu, Chunsheng; Jiang, Jinfang; Zhang, Wenbo

    2017-02-08

    Marine environmental monitoring provides crucial information and support for the exploitation, utilization, and protection of marine resources. With the rapid development of information technology, the development of three-dimensional underwater acoustic sensor networks (3D UASNs) provides a novel strategy to acquire marine environment information conveniently, efficiently and accurately. However, the specific propagation effects of acoustic communication channel lead to decreased successful information delivery probability with increased distance. Therefore, we investigate two probabilistic neighborhood-based data collection algorithms for 3D UASNs which are based on a probabilistic acoustic communication model instead of the traditional deterministic acoustic communication model. An autonomous underwater vehicle (AUV) is employed to traverse along the designed path to collect data from neighborhoods. For 3D UASNs without prior deployment knowledge, partitioning the network into grids can allow the AUV to visit the central location of each grid for data collection. For 3D UASNs in which the deployment knowledge is known in advance, the AUV only needs to visit several selected locations by constructing a minimum probabilistic neighborhood covering set to reduce data latency. Otherwise, by increasing the transmission rounds, our proposed algorithms can provide a tradeoff between data collection latency and information gain. These algorithms are compared with basic Nearest-neighbor Heuristic algorithm via simulations. Simulation analyses show that our proposed algorithms can efficiently reduce the average data collection completion time, corresponding to a decrease of data latency.

  7. Development and Implementation of a Web-Enabled 3D Consultation Tool for Breast Augmentation Surgery Based on 3D-Image Reconstruction of 2D Pictures

    PubMed Central

    Garcia, Jaime; Olariu, Radu; Dindoyal, Irving; Le Huu, Serge

    2012-01-01

    Background Producing a rich, personalized Web-based consultation tool for plastic surgeons and patients is challenging. Objective (1) To develop a computer tool that allows individual reconstruction and simulation of 3-dimensional (3D) soft tissue from ordinary digital photos of breasts, (2) to implement a Web-based, worldwide-accessible preoperative surgical planning platform for plastic surgeons, and (3) to validate this tool through a quality control analysis by comparing 3D laser scans of the patients with the 3D reconstructions with this tool from original 2-dimensional (2D) pictures of the same patients. Methods The proposed system uses well-established 2D digital photos for reconstruction into a 3D torso, which is then available to the user for interactive planning. The simulation is performed on dedicated servers, accessible via Internet. It allows the surgeon, together with the patient, to previsualize the impact of the proposed breast augmentation directly during the consultation before a surgery is decided upon. We retrospectively conduced a quality control assessment of available anonymized pre- and postoperative 2D digital photographs of patients undergoing breast augmentation procedures. The method presented above was used to reconstruct 3D pictures from 2D digital pictures. We used a laser scanner capable of generating a highly accurate surface model of the patient’s anatomy to acquire ground truth data. The quality of the computed 3D reconstructions was compared with the ground truth data used to perform both qualitative and quantitative evaluations. Results We evaluated the system on 11 clinical cases for surface reconstructions and 4 clinical cases of postoperative simulations, using laser surface scan technologies showing a mean reconstruction error between 2 and 4 mm and a maximum outlier error of 16 mm. Qualitative and quantitative analyses from plastic surgeons demonstrate the potential of these new emerging technologies. Conclusions We

  8. The design of red-blue 3D video fusion system based on DM642

    NASA Astrophysics Data System (ADS)

    Fu, Rongguo; Luo, Hao; Lv, Jin; Feng, Shu; Wei, Yifang; Zhang, Hao

    2016-10-01

    Aiming at the uncertainty of traditional 3D video capturing including camera focal lengths, distance and angle parameters between two cameras, a red-blue 3D video fusion system based on DM642 hardware processing platform is designed with the parallel optical axis. In view of the brightness reduction of traditional 3D video, the brightness enhancement algorithm based on human visual characteristics is proposed and the luminance component processing method based on YCbCr color space is also proposed. The BIOS real-time operating system is used to improve the real-time performance. The video processing circuit with the core of DM642 enhances the brightness of the images, then converts the video signals of YCbCr to RGB and extracts the R component from one camera, so does the other video and G, B component are extracted synchronously, outputs 3D fusion images finally. The real-time adjustments such as translation and scaling of the two color components are realized through the serial communication between the VC software and BIOS. The system with the method of adding red-blue components reduces the lost of the chrominance components and makes the picture color saturation reduce to more than 95% of the original. Enhancement algorithm after optimization to reduce the amount of data fusion in the processing of video is used to reduce the fusion time and watching effect is improved. Experimental results show that the system can capture images in near distance, output red-blue 3D video and presents the nice experiences to the audience wearing red-blue glasses.

  9. Prediction of enzyme function based on 3D templates of evolutionarily important amino acids

    PubMed Central

    Kristensen, David M; Ward, R Matthew; Lisewski, Andreas Martin; Erdin, Serkan; Chen, Brian Y; Fofanov, Viacheslav Y; Kimmel, Marek; Kavraki, Lydia E; Lichtarge, Olivier

    2008-01-01

    Background Structural genomics projects such as the Protein Structure Initiative (PSI) yield many new structures, but often these have no known molecular functions. One approach to recover this information is to use 3D templates – structure-function motifs that consist of a few functionally critical amino acids and may suggest functional similarity when geometrically matched to other structures. Since experimentally determined functional sites are not common enough to define 3D templates on a large scale, this work tests a computational strategy to select relevant residues for 3D templates. Results Based on evolutionary information and heuristics, an Evolutionary Trace Annotation (ETA) pipeline built templates for 98 enzymes, half taken from the PSI, and sought matches in a non-redundant structure database. On average each template matched 2.7 distinct proteins, of which 2.0 share the first three Enzyme Commission digits as the template's enzyme of origin. In many cases (61%) a single most likely function could be predicted as the annotation with the most matches, and in these cases such a plurality vote identified the correct function with 87% accuracy. ETA was also found to be complementary to sequence homology-based annotations. When matches are required to both geometrically match the 3D template and to be sequence homologs found by BLAST or PSI-BLAST, the annotation accuracy is greater than either method alone, especially in the region of lower sequence identity where homology-based annotations are least reliable. Conclusion These data suggest that knowledge of evolutionarily important residues improves functional annotation among distant enzyme homologs. Since, unlike other 3D template approaches, the ETA method bypasses the need for experimental knowledge of the catalytic mechanism, it should prove a useful, large scale, and general adjunct to combine with other methods to decipher protein function in the structural proteome. PMID:18190718

  10. Construction of compactly supported biorthogonal wavelet based on Human Visual System

    NASA Astrophysics Data System (ADS)

    Hu, Haiping; Hou, Weidong; Liu, Hong; Mo, Yu L.

    2000-11-01

    As an important analysis tool, wavelet transform has made a great development in image compression coding, since Daubechies constructed a kind of compact support orthogonal wavelet and Mallat presented a fast pyramid algorithm for wavelet decomposition and reconstruction. In order to raise the compression ratio and improve the visual quality of reconstruction, it becomes very important to find a wavelet basis that fits the human visual system (HVS). Marr wavelet, as it is known, is a kind of wavelet, so it is not suitable for implementation of image compression coding. In this paper, a new method is provided to construct a kind of compactly supported biorthogonal wavelet based on human visual system, we employ the genetic algorithm to construct compactly supported biorthogonal wavelet that can approximate the modulation transform function for HVS. The novel constructed wavelet is applied to image compression coding in our experiments. The experimental results indicate that the visual quality of reconstruction with the new kind of wavelet is equivalent to other compactly biorthogonal wavelets in the condition of the same bit rate. It has good performance of reconstruction, especially used in texture image compression coding.

  11. 3D Air Filtration Modeling for Nanofiber Based Filters in the Ultrafine Particle Size Range

    NASA Astrophysics Data System (ADS)

    Sambaer, Wannes; Zatloukal, Martin; Kimmer, Dusan

    2011-07-01

    In this work, novel 3D filtration model for nanofiber based filters has been proposed and tested. For the model validation purposes, filtration efficiency characteristics of two different polyurethane nanofiber based structures (prepared by the electrospinning process) were determined experimentally in the ultrafine particle size range (20-400 nm). It has been found that the proposed model is able to reasonably predict the measured filtration efficiency curves for both tested samples.

  12. Gearbox diagnostics using wavelet-based windowing technique

    NASA Astrophysics Data System (ADS)

    Omar, F. K.; Gaouda, A. M.

    2009-08-01

    In extracting gear box acoustic signals embedded in excessive noise, the need for an online and automated tool becomes a crucial necessity. One of the recent approaches that have gained some acceptance within the research arena is the Wavelet multi-resolution analysis (WMRA). However selecting an accurate mother wavelet, defining dynamic threshold values and identifying the resolution levels to be considered in gearboxes fault detection and diagnosis are still challenging tasks. This paper proposes a novel wavelet-based technique for detecting, locating and estimating the severity of defects in gear tooth fracture. The proposed technique enhances the WMRA by decomposing the noisy data into different resolution levels while data sliding it into Kaiser's window. Only the maximum expansion coefficients at each resolution level are used in de-noising, detecting and measuring the severity of the defects. A small set of coefficients is used in the monitoring process without assigning threshold values or performing signal reconstruction. The proposed monitoring technique has been applied to a laboratory data corrupted with high noise level.

  13. Wavelet-based embedded zerotree extension to color coding

    NASA Astrophysics Data System (ADS)

    Franques, Victoria T.

    1998-03-01

    Recently, a new image compression algorithm was developed which employs wavelet transform and a simple binary linear quantization scheme with an embedded coding technique to perform data compaction. This new family of coder, Embedded Zerotree Wavelet (EZW), provides a better compression performance than the current JPEG coding standard for low bit rates. Since EZW coding algorithm emerged, all of the published coding results related to this coding technique are on monochrome images. In this paper the author has enhanced the original coding algorithm to yield a better compression ratio, and has extended the wavelet-based zerotree coding to color images. Color imagery is often represented by several components, such as RGB, in which each component is generally processed separately. With color coding, each component could be compressed individually in the same manner as a monochrome image, therefore requiring a threefold increase in processing time. Most image coding standards employ de-correlated components, such as YIQ or Y, CB, CR and subsampling of the 'chroma' components, such coding technique is employed here. Results of the coding, including reconstructed images and coding performance, will be presented.

  14. An Evolved Wavelet Library Based on Genetic Algorithm

    PubMed Central

    Vaithiyanathan, D.; Seshasayanan, R.; Kunaraj, K.; Keerthiga, J.

    2014-01-01

    As the size of the images being captured increases, there is a need for a robust algorithm for image compression which satiates the bandwidth limitation of the transmitted channels and preserves the image resolution without considerable loss in the image quality. Many conventional image compression algorithms use wavelet transform which can significantly reduce the number of bits needed to represent a pixel and the process of quantization and thresholding further increases the compression. In this paper the authors evolve two sets of wavelet filter coefficients using genetic algorithm (GA), one for the whole image portion except the edge areas and the other for the portions near the edges in the image (i.e., global and local filters). Images are initially separated into several groups based on their frequency content, edges, and textures and the wavelet filter coefficients are evolved separately for each group. As there is a possibility of the GA settling in local maximum, we introduce a new shuffling operator to prevent the GA from this effect. The GA used to evolve filter coefficients primarily focuses on maximizing the peak signal to noise ratio (PSNR). The evolved filter coefficients by the proposed method outperform the existing methods by a 0.31 dB improvement in the average PSNR and a 0.39 dB improvement in the maximum PSNR. PMID:25405225

  15. Redundant Discrete Wavelet Transform Based Super-Resolution Using Sub-Pixel Image Registration

    DTIC Science & Technology

    2003-03-01

    AFIT/GE/ENG/03-18 REDUNDANT DISCRETE WAVELET TRANSFORM BASED SUPER-RESOLUTION USING SUB-PIXEL IMAGE REGISTRATION THESIS Daniel L. Ward Second...position of the United States Air Force, Department of Defense, or the United States Government. AFIT/GE/ENG/03-18 REDUNDANT DISCRETE WAVELET TRANSFORM BASED...O3-18 REDUNDANT DISCRETE WAVELET TRANSFORM BASED SUPER-RESOLUTION USING SUB-PIXEL IMAGE REGISTRATION THESIS Daniel Lee Ward, B.S.E.E. Second

  16. 4DCBCT-based motion modeling and 3D fluoroscopic image generation for lung cancer radiotherapy

    NASA Astrophysics Data System (ADS)

    Dhou, Salam; Hurwitz, Martina; Mishra, Pankaj; Berbeco, Ross; Lewis, John

    2015-03-01

    A method is developed to build patient-specific motion models based on 4DCBCT images taken at treatment time and use them to generate 3D time-varying images (referred to as 3D fluoroscopic images). Motion models are built by applying Principal Component Analysis (PCA) on the displacement vector fields (DVFs) estimated by performing deformable image registration on each phase of 4DCBCT relative to a reference phase. The resulting PCA coefficients are optimized iteratively by comparing 2D projections captured at treatment time with projections estimated using the motion model. The optimized coefficients are used to generate 3D fluoroscopic images. The method is evaluated using anthropomorphic physical and digital phantoms reproducing real patient trajectories. For physical phantom datasets, the average tumor localization error (TLE) and (95th percentile) in two datasets were 0.95 (2.2) mm. For digital phantoms assuming superior image quality of 4DCT and no anatomic or positioning disparities between 4DCT and treatment time, the average TLE and the image intensity error (IIE) in six datasets were smaller using 4DCT-based motion models. When simulating positioning disparities and tumor baseline shifts at treatment time compared to planning 4DCT, the average TLE (95th percentile) and IIE were 4.2 (5.4) mm and 0.15 using 4DCT-based models, while they were 1.2 (2.2) mm and 0.10 using 4DCBCT-based ones, respectively. 4DCBCT-based models were shown to perform better when there are positioning and tumor baseline shift uncertainties at treatment time. Thus, generating 3D fluoroscopic images based on 4DCBCT-based motion models can capture both inter- and intra- fraction anatomical changes during treatment.

  17. SU-F-BRF-08: Conformal Mapping-Based 3D Surface Matching and Registration

    SciTech Connect

    Song, Y; Zeng, W; Gu, X; Liu, C

    2014-06-15

    Purpose: Recently, non-rigid 3D surface matching and registration has been used extensively in engineering and medicine. However, matching 3D surfaces undergoing non-rigid deformation accurately is still a challenging mathematical problem. In this study, we present a novel algorithm to address this issue by introducing intrinsic symmetry to the registration Methods: Our computational algorithm for symmetric conformal mapping is divided into three major steps: 1) Finding the symmetric plane; 2) Finding feature points; and 3) Performing cross registration. The key strategy is to preserve the symmetry during the conformal mapping, such that the image on the parameter domain is symmetric and the area distortion factor on the parameter image is also symmetric. Several novel algorithms were developed using different conformal geometric tools. One was based on solving Riemann-Cauchy equation and the other one employed curvature flow Results: Our algorithm was implemented using generic C++ on Windows XP and used conjugate gradient search optimization for acceleration. The human face 3D surface images were acquired using a high speed 3D scanner based on the phase-shifting method. The scanning speed was 30 frames/sec. The image resolution for each frame was 640 × 480. For 3D human face surfaces with different expressions, postures, and boundaries, our algorithms were able to produce consistent result on the texture pattern on the overlapping region Conclusion: We proposed a novel algorithm to improve the robustness of conformal geometric methods by incorporating the symmetric information into the mapping process. To objectively evaluate its performance, we compared it with most existing techniques. Experimental results indicated that our method outperformed all the others in terms of robustness. The technique has a great potential in real-time patient monitoring and tracking in image-guided radiation therapy.

  18. Automatic system for 3D reconstruction of the chick eye based on digital photographs.

    PubMed

    Wong, Alexander; Genest, Reno; Chandrashekar, Naveen; Choh, Vivian; Irving, Elizabeth L

    2012-01-01

    The geometry of anatomical specimens is very complex and accurate 3D reconstruction is important for morphological studies, finite element analysis (FEA) and rapid prototyping. Although magnetic resonance imaging, computed tomography and laser scanners can be used for reconstructing biological structures, the cost of the equipment is fairly high and specialised technicians are required to operate the equipment, making such approaches limiting in terms of accessibility. In this paper, a novel automatic system for 3D surface reconstruction of the chick eye from digital photographs of a serially sectioned specimen is presented as a potential cost-effective and practical alternative. The system is designed to allow for automatic detection of the external surface of the chick eye. Automatic alignment of the photographs is performed using a combination of coloured markers and an algorithm based on complex phase order likelihood that is robust to noise and illumination variations. Automatic segmentation of the external boundaries of the eye from the aligned photographs is performed using a novel level-set segmentation approach based on a complex phase order energy functional. The extracted boundaries are sampled to construct a 3D point cloud, and a combination of Delaunay triangulation and subdivision surfaces is employed to construct the final triangular mesh. Experimental results using digital photographs of the chick eye show that the proposed system is capable of producing accurate 3D reconstructions of the external surface of the eye. The 3D model geometry is similar to a real chick eye and could be used for morphological studies and FEA.

  19. Grammar-based Automatic 3D Model Reconstruction from Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Yu, Q.; Helmholz, P.; Belton, D.; West, G.

    2014-04-01

    The automatic reconstruction of 3D buildings has been an important research topic during the last years. In this paper, a novel method is proposed to automatically reconstruct the 3D building models from segmented data based on pre-defined formal grammar and rules. Such segmented data can be extracted e.g. from terrestrial or mobile laser scanning devices. Two steps are considered in detail. The first step is to transform the segmented data into 3D shapes, for instance using the DXF (Drawing Exchange Format) format which is a CAD data file format used for data interchange between AutoCAD and other program. Second, we develop a formal grammar to describe the building model structure and integrate the pre-defined grammars into the reconstruction process. Depending on the different segmented data, the selected grammar and rules are applied to drive the reconstruction process in an automatic manner. Compared with other existing approaches, our proposed method allows the model reconstruction directly from 3D shapes and takes the whole building into account.

  20. Cranial Base Superimposition for 3D Evaluation of Soft Tissue Changes

    PubMed Central

    Cevidanes, Lucia H.C.; Motta, Alexandre; Proffit, William R.; Ackerman, James L.; Styner, Martin

    2009-01-01

    The recent emphasis on soft tissues as the limiting factor in treatment and on soft tissue relationships in establishing the goals of treatment has made 3D analysis of soft tissues more important in diagnosis and treatment planning. It is equally important to be able to detect changes in the facial soft tissues produced by growth and/or treatment. This requires structures of reference for superimposition, and a way to display the changes with quantitative information. This paper outlines a technique for quantifying facial soft tissue changes as viewed in CBCT data, using fully-automated voxel-wise registration of the cranial base surface. The assessment of change of soft tissues is done via calculation of the Euclidean surface distances between the 3D models. Color maps are used for visual assessment of the location and quantification of changes. This methodology allows a detailed examination of soft tissue changes with growth and/or treatment. Because of the lack of stable references with 3D photogrammetry, 3D photography and laser scanning, soft tissue changes cannot be accurately quantified by these methods. PMID:20381752

  1. Standardization based on human factors for 3D display: performance characteristics and measurement methods

    NASA Astrophysics Data System (ADS)

    Uehara, Shin-ichi; Ujike, Hiroyasu; Hamagishi, Goro; Taira, Kazuki; Koike, Takafumi; Kato, Chiaki; Nomura, Toshio; Horikoshi, Tsutomu; Mashitani, Ken; Yuuki, Akimasa; Izumi, Kuniaki; Hisatake, Yuzo; Watanabe, Naoko; Umezu, Naoaki; Nakano, Yoshihiko

    2010-02-01

    We are engaged in international standardization activities for 3D displays. We consider that for a sound development of 3D displays' market, the standards should be based on not only mechanism of 3D displays, but also human factors for stereopsis. However, we think that there is no common understanding on what the 3D display should be and that the situation makes developing the standards difficult. In this paper, to understand the mechanism and human factors, we focus on a double image, which occurs in some conditions on an autostereoscopic display. Although the double image is generally considered as an unwanted effect, we consider that whether the double image is unwanted or not depends on the situation and that there are some allowable double images. We tried to classify the double images into the unwanted and the allowable in terms of the display mechanism and visual ergonomics for stereopsis. The issues associated with the double image are closely related to performance characteristics for the autostereoscopic display. We also propose performance characteristics, measurement and analysis methods to represent interocular crosstalk and motion parallax.

  2. 3D animation of facial plastic surgery based on computer graphics

    NASA Astrophysics Data System (ADS)

    Zhang, Zonghua; Zhao, Yan

    2013-12-01

    More and more people, especial women, are getting desired to be more beautiful than ever. To some extent, it becomes true because the plastic surgery of face was capable in the early 20th and even earlier as doctors just dealing with war injures of face. However, the effect of post-operation is not always satisfying since no animation could be seen by the patients beforehand. In this paper, by combining plastic surgery of face and computer graphics, a novel method of simulated appearance of post-operation will be given to demonstrate the modified face from different viewpoints. The 3D human face data are obtained by using 3D fringe pattern imaging systems and CT imaging systems and then converted into STL (STereo Lithography) file format. STL file is made up of small 3D triangular primitives. The triangular mesh can be reconstructed by using hash function. Top triangular meshes in depth out of numbers of triangles must be picked up by ray-casting technique. Mesh deformation is based on the front triangular mesh in the process of simulation, which deforms interest area instead of control points. Experiments on face model show that the proposed 3D animation facial plastic surgery can effectively demonstrate the simulated appearance of post-operation.

  3. Uniform Local Binary Pattern Based Texture-Edge Feature for 3D Human Behavior Recognition.

    PubMed

    Ming, Yue; Wang, Guangchao; Fan, Chunxiao

    2015-01-01

    With the rapid development of 3D somatosensory technology, human behavior recognition has become an important research field. Human behavior feature analysis has evolved from traditional 2D features to 3D features. In order to improve the performance of human activity recognition, a human behavior recognition method is proposed, which is based on a hybrid texture-edge local pattern coding feature extraction and integration of RGB and depth videos information. The paper mainly focuses on background subtraction on RGB and depth video sequences of behaviors, extracting and integrating historical images of the behavior outlines, feature extraction and classification. The new method of 3D human behavior recognition has achieved the rapid and efficient recognition of behavior videos. A large number of experiments show that the proposed method has faster speed and higher recognition rate. The recognition method has good robustness for different environmental colors, lightings and other factors. Meanwhile, the feature of mixed texture-edge uniform local binary pattern can be used in most 3D behavior recognition.

  4. 3D printed PLA-based scaffolds: a versatile tool in regenerative medicine.

    PubMed

    Serra, Tiziano; Mateos-Timoneda, Miguel A; Planell, Josep A; Navarro, Melba

    2013-10-01

    Rapid prototyping (RP), also known as additive manufacturing (AM), has been well received and adopted in the biomedical field. The capacity of this family of techniques to fabricate customized 3D structures with complex geometries and excellent reproducibility has revolutionized implantology and regenerative medicine. In particular, nozzle-based systems allow the fabrication of high-resolution polylactic acid (PLA) structures that are of interest in regenerative medicine. These 3D structures find interesting applications in the regenerative medicine field where promising applications including biodegradable templates for tissue regeneration purposes, 3D in vitro platforms for studying cell response to different scaffolds conditions and for drug screening are considered among others. Scaffolds functionality depends not only on the fabrication technique, but also on the material used to build the 3D structure, the geometry and inner architecture of the structure, and the final surface properties. All being crucial parameters affecting scaffolds success. This Commentary emphasizes the importance of these parameters in scaffolds' fabrication and also draws the attention toward the versatility of these PLA scaffolds as a potential tool in regenerative medicine and other medical fields.

  5. Exploring conformational search protocols for ligand-based virtual screening and 3-D QSAR modeling

    NASA Astrophysics Data System (ADS)

    Cappel, Daniel; Dixon, Steven L.; Sherman, Woody; Duan, Jianxin

    2015-02-01

    3-D ligand conformations are required for most ligand-based drug design methods, such as pharmacophore modeling, shape-based screening, and 3-D QSAR model building. Many studies of conformational search methods have focused on the reproduction of crystal structures (i.e. bioactive conformations); however, for ligand-based modeling the key question is how to generate a ligand alignment that produces the best results for a given query molecule. In this work, we study different conformation generation modes of ConfGen and the impact on virtual screening (Shape Screening and e-Pharmacophore) and QSAR predictions (atom-based and field-based). In addition, we develop a new search method, called common scaffold alignment, that automatically detects the maximum common scaffold between each screening molecule and the query to ensure identical coordinates of the common core, thereby minimizing the noise introduced by analogous parts of the molecules. In general, we find that virtual screening results are relatively insensitive to the conformational search protocol; hence, a conformational search method that generates fewer conformations could be considered "better" because it is more computationally efficient for screening. However, for 3-D QSAR modeling we find that more thorough conformational sampling tends to produce better QSAR predictions. In addition, significant improvements in QSAR predictions are obtained with the common scaffold alignment protocol developed in this work, which focuses conformational sampling on parts of the molecules that are not part of the common scaffold.

  6. Fragment-based strategy for structural optimization in combination with 3D-QSAR.

    PubMed

    Yuan, Haoliang; Tai, Wenting; Hu, Shihe; Liu, Haichun; Zhang, Yanmin; Yao, Sihui; Ran, Ting; Lu, Shuai; Ke, Zhipeng; Xiong, Xiao; Xu, Jinxing; Chen, Yadong; Lu, Tao

    2013-10-01

    Fragment-based drug design has emerged as an important methodology for lead discovery and drug design. Different with other studies focused on fragment library design and active fragment identification, a fragment-based strategy was developed in combination with three-dimensional quantitative structure-activity relationship (3D-QSAR) for structural optimization in this study. Based on a validated scaffold or fragment hit, a series of structural optimization was conducted to convert it to lead compounds, including 3D-QSAR modelling, active site analysis, fragment-based structural optimization and evaluation of new molecules. 3D-QSAR models and active site analysis provided sufficient information for confirming the SAR and pharmacophoric features for fragments. This strategy was evaluated through the structural optimization on a c-Met inhibitor scaffold 5H-benzo[4,5]cyclohepta[1,2-b]pyridin-5-one, which resulted in an c-Met inhibitor with high inhibitory activity. Our study suggested the effectiveness of this fragment-based strategy and the druggability of our newly explored active region. The reliability of this strategy indicated it could also be applied to facilitate lead optimization of other targets.

  7. Quantitative analysis of the central-chest lymph nodes based on 3D MDCT image data

    NASA Astrophysics Data System (ADS)

    Lu, Kongkuo; Bascom, Rebecca; Mahraj, Rickhesvar P. M.; Higgins, William E.

    2009-02-01

    Lung cancer is the leading cause of cancer death in the United States. In lung-cancer staging, central-chest lymph nodes and associated nodal stations, as observed in three-dimensional (3D) multidetector CT (MDCT) scans, play a vital role. However, little work has been done in relation to lymph nodes, based on MDCT data, due to the complicated phenomena that give rise to them. Using our custom computer-based system for 3D MDCT-based pulmonary lymph-node analysis, we conduct a detailed study of lymph nodes as depicted in 3D MDCT scans. In this work, the Mountain lymph-node stations are automatically defined by the system. These defined stations, in conjunction with our system's image processing and visualization tools, facilitate lymph-node detection, classification, and segmentation. An expert pulmonologist, chest radiologist, and trained technician verified the accuracy of the automatically defined stations and indicated observable lymph nodes. Next, using semi-automatic tools in our system, we defined all indicated nodes. Finally, we performed a global quantitative analysis of the characteristics of the observed nodes and stations. This study drew upon a database of 32 human MDCT chest scans. 320 Mountain-based stations (10 per scan) and 852 pulmonary lymph nodes were defined overall from this database. Based on the numerical results, over 90% of the automatically defined stations were deemed accurate. This paper also presents a detailed summary of central-chest lymph-node characteristics for the first time.

  8. Fragment-based strategy for structural optimization in combination with 3D-QSAR

    NASA Astrophysics Data System (ADS)

    Yuan, Haoliang; Tai, Wenting; Hu, Shihe; Liu, Haichun; Zhang, Yanmin; Yao, Sihui; Ran, Ting; Lu, Shuai; Ke, Zhipeng; Xiong, Xiao; Xu, Jinxing; Chen, Yadong; Lu, Tao

    2013-10-01

    Fragment-based drug design has emerged as an important methodology for lead discovery and drug design. Different with other studies focused on fragment library design and active fragment identification, a fragment-based strategy was developed in combination with three-dimensional quantitative structure-activity relationship (3D-QSAR) for structural optimization in this study. Based on a validated scaffold or fragment hit, a series of structural optimization was conducted to convert it to lead compounds, including 3D-QSAR modelling, active site analysis, fragment-based structural optimization and evaluation of new molecules. 3D-QSAR models and active site analysis provided sufficient information for confirming the SAR and pharmacophoric features for fragments. This strategy was evaluated through the structural optimization on a c-Met inhibitor scaffold 5H-benzo[4,5]cyclohepta[1,2-b]pyridin-5-one, which resulted in an c-Met inhibitor with high inhibitory activity. Our study suggested the effectiveness of this fragment-based strategy and the druggability of our newly explored active region. The reliability of this strategy indicated it could also be applied to facilitate lead optimization of other targets.

  9. Voxel-Based 3-D Tree Modeling from Lidar Images for Extracting Tree Structual Information

    NASA Astrophysics Data System (ADS)

    Hosoi, F.

    2014-12-01

    Recently, lidar (light detection and ranging) has been used to extracting tree structural information. Portable scanning lidar systems can capture the complex shape of individual trees as a 3-D point-cloud image. 3-D tree models reproduced from the lidar-derived 3-D image can be used to estimate tree structural parameters. We have proposed the voxel-based 3-D modeling for extracting tree structural parameters. One of the tree parameters derived from the voxel modeling is leaf area density (LAD). We refer to the method as the voxel-based canopy profiling (VCP) method. In this method, several measurement points surrounding the canopy and optimally inclined laser beams are adopted for full laser beam illumination of whole canopy up to the internal. From obtained lidar image, the 3-D information is reproduced as the voxel attributes in the 3-D voxel array. Based on the voxel attributes, contact frequency of laser beams on leaves is computed and LAD in each horizontal layer is obtained. This method offered accurate LAD estimation for individual trees and woody canopy trees. For more accurate LAD estimation, the voxel model was constructed by combining airborne and portable ground-based lidar data. The profiles obtained by the two types of lidar complemented each other, thus eliminating blind regions and yielding more accurate LAD profiles than could be obtained by using each type of lidar alone. Based on the estimation results, we proposed an index named laser beam coverage index, Ω, which relates to the lidar's laser beam settings and a laser beam attenuation factor. It was shown that this index can be used for adjusting measurement set-up of lidar systems and also used for explaining the LAD estimation error using different types of lidar systems. Moreover, we proposed a method to estimate woody material volume as another application of the voxel tree modeling. In this method, voxel solid model of a target tree was produced from the lidar image, which is composed of

  10. Wavelet-based multiresolution with n-th-root-of-2 Subdivision

    SciTech Connect

    Linsen, L; Pascucci, V; Duchaineau, M A; Hamann, B; Joy, K I

    2004-12-16

    Multiresolution methods are a common technique used for dealing with large-scale data and representing it at multiple levels of detail. The authors present a multiresolution hierarchy construction based on n{radical}2 subdivision, which has all the advantages of a regular data organization scheme while reducing the drawback of coarse granularity. The n{radical}2-subdivision scheme only doubles the number of vertices in each subdivision step regardless of dimension n. They describe the construction of 2D, 3D, and 4D hierarchies representing surfaces, volume data, and time-varying volume data, respectively. The 4D approach supports spatial and temporal scalability. For high-quality data approximation on each level of detail, they use downsampling filters based on n-variate B-spline wavelets. They present a B-spline wavelet lifting scheme for n{radical}2-subdivision steps to obtain small or narrow filters. Narrow filters support adaptive refinement and out-of-core data exploration techniques.

  11. Dynamic WIFI-Based Indoor Positioning in 3D Virtual World

    NASA Astrophysics Data System (ADS)

    Chan, S.; Sohn, G.; Wang, L.; Lee, W.

    2013-11-01

    A web-based system based on the 3DTown project was proposed using Google Earth plug-in that brings information from indoor positioning devices and real-time sensors into an integrated 3D indoor and outdoor virtual world to visualize the dynamics of urban life within the 3D context of a city. We addressed limitation of the 3DTown project with particular emphasis on video surveillance camera used for indoor tracking purposes. The proposed solution was to utilize wireless local area network (WLAN) WiFi as a replacement technology for localizing objects of interest due to the wide spread availability and large coverage area of WiFi in indoor building spaces. Indoor positioning was performed using WiFi without modifying existing building infrastructure or introducing additional access points (AP)s. A hybrid probabilistic approach was used for indoor positioning based on previously recorded WiFi fingerprint database in the Petrie Science and Engineering building at York University. In addition, we have developed a 3D building modeling module that allows for efficient reconstruction of outdoor building models to be integrated with indoor building models; a sensor module for receiving, distributing, and visualizing real-time sensor data; and a web-based visualization module for users to explore the dynamic urban life in a virtual world. In order to solve the problems in the implementation of the proposed system, we introduce approaches for integration of indoor building models with indoor positioning data, as well as real-time sensor information and visualization on the web-based system. In this paper we report the preliminary results of our prototype system, demonstrating the system's capability for implementing a dynamic 3D indoor and outdoor virtual world that is composed of discrete modules connected through pre-determined communication protocols.

  12. Novel 3D bismuth-based coordination polymers: Synthesis, structure, and second harmonic generation properties

    SciTech Connect

    Wibowo, Arief C.; Smith, Mark D.; Yeon, Jeongho; Halasyamani, P. Shiv; Loye, Hans-Conrad zur

    2012-11-15

    Two new 3D bismuth containing coordination polymers are reported along with their single crystal structures and SHG properties. Compound 1: Bi{sub 2}O{sub 2}(pydc) (pydc=pyridine-2, 5-dicarboxylate), crystallizes in the monoclinic, polar space group, P2{sub 1} (a=9.6479(9) A, b=4.2349(4) A, c=11.9615(11) A, {beta}=109.587(1) Degree-Sign ), which contains Bi{sub 2}O{sub 2} chains that are connected into a 3D structure via the pydc ligands. Compound 2: Bi{sub 4}Na{sub 4}(1R3S-cam){sub 8}(EtOH){sub 3.1}(H{sub 2}O){sub 3.4} (1R3S cam=1R3S-camphoric acid) crystallizes in the monoclinic, polar space group, P2{sub 1} (a=19.0855(7) A, b=13.7706(5) A, c=19.2429(7) A, {beta}=90.701(1) Degree-Sign ) and is a true 3D coordination polymer. These are two example of SHG compounds prepared using unsymmetric ligands (compound 1) or chiral ligands (compound 2), together with metals that often exhibit stereochemically-active lone pairs, such as Bi{sup 3+}, a synthetic approach that resulted in polar, non-centrosymmetric, 3D metal-organic coordination polymer. - Graphical Abstract: Structures of two new, polar, 3D Bismuth(III)-based coordination polymers: Bi{sub 2}O{sub 2}(pydc) (compound 1), and Bi{sub 4}Na{sub 4}(1R3S-cam){sub 8}(EtOH){sub 3.1}(H{sub 2}O){sub 3.4} (compound 2). Highlights: Black-Right-Pointing-Pointer New, polar, 3D Bismuth(III)-based coordination polymers. Black-Right-Pointing-Pointer First polar bismuth-based coordination polymers synthesized via a 'hybrid' strategy. Black-Right-Pointing-Pointer Combination of stereochemically-active lone pairs and unsymmetrical or chiral ligands. Black-Right-Pointing-Pointer Synthesis of class C-SHG materials based on Kurtz-Perry categories.

  13. Depth-based coding of MVD data for 3D video extension of H.264/AVC

    NASA Astrophysics Data System (ADS)

    Rusanovskyy, Dmytro; Hannuksela, Miska M.; Su, Wenyi

    2013-06-01

    This paper describes a novel approach of using depth information for advanced coding of associated video data in Multiview Video plus Depth (MVD)-based 3D video systems. As a possible implementation of this conception, we describe two coding tools that have been developed for H.264/AVC based 3D Video Codec as response to Moving Picture Experts Group (MPEG) Call for Proposals (CfP). These tools are Depth-based Motion Vector Prediction (DMVP) and Backward View Synthesis Prediction (BVSP). Simulation results conducted under JCT-3V/MPEG 3DV Common Test Conditions show, that proposed in this paper tools reduce bit rate of coded video data by 15% of average delta bit rate reduction, which results in 13% of bit rate savings on total for the MVD data over the state-of-the-art MVC+D coding. Moreover, presented in this paper conception of depth-based coding of video has been further developed by MPEG 3DV and JCT-3V and this work resulted in even higher compression efficiency, bringing about 20% of delta bit rate reduction on total for coded MVD data over the reference MVC+D coding. Considering significant gains, proposed in this paper coding approach can be beneficial for development of new 3D video coding standards. [Figure not available: see fulltext.

  14. 3D model-based detection and tracking for space autonomous and uncooperative rendezvous

    NASA Astrophysics Data System (ADS)

    Shang, Yang; Zhang, Yueqiang; Liu, Haibo

    2015-10-01

    In order to fully navigate using a vision sensor, a 3D edge model based detection and tracking technique was developed. Firstly, we proposed a target detection strategy over a sequence of several images from the 3D model to initialize the tracking. The overall purpose of such approach is to robustly match each image with the model views of the target. Thus we designed a line segment detection and matching method based on the multi-scale space technology. Experiments on real images showed that our method is highly robust under various image changes. Secondly, we proposed a method based on 3D particle filter (PF) coupled with M-estimation to track and estimate the pose of the target efficiently. In the proposed approach, a similarity observation model was designed according to a new distance function of line segments. Then, based on the tracking results of PF, the pose was optimized using M-estimation. Experiments indicated that the proposed method can effectively track and accurately estimate the pose of freely moving target in unconstrained environment.

  15. 3D tensor-based blind multispectral image decomposition for tumor demarcation

    NASA Astrophysics Data System (ADS)

    Kopriva, Ivica; Peršin, Antun

    2010-03-01

    Blind decomposition of multi-spectral fluorescent image for tumor demarcation is formulated exploiting tensorial structure of the image. First contribution of the paper is identification of the matrix of spectral responses and 3D tensor of spatial distributions of the materials present in the image from Tucker3 or PARAFAC models of 3D image tensor. Second contribution of the paper is clustering based estimation of the number of the materials present in the image as well as matrix of their spectral profiles. 3D tensor of the spatial distributions of the materials is recovered through 3-mode multiplication of the multi-spectral image tensor and inverse of the matrix of spectral profiles. Tensor representation of the multi-spectral image preserves its local spatial structure that is lost, due to vectorization process, when matrix factorization-based decomposition methods (such as non-negative matrix factorization and independent component analysis) are used. Superior performance of the tensor-based image decomposition over matrix factorization-based decompositions is demonstrated on experimental red-green-blue (RGB) image with known ground truth as well as on RGB fluorescent images of the skin tumor (basal cell carcinoma).

  16. 3D face recognition based on the hierarchical score-level fusion classifiers

    NASA Astrophysics Data System (ADS)

    Mráček, Štěpán.; Váša, Jan; Lankašová, Karolína; Drahanský, Martin; Doležel, Michal

    2014-05-01

    This paper describes the 3D face recognition algorithm that is based on the hierarchical score-level fusion clas-sifiers. In a simple (unimodal) biometric pipeline, the feature vector is extracted from the input data and subsequently compared with the template stored in the database. In our approachm, we utilize several feature extraction algorithms. We use 6 different image representations of the input 3D face data. Moreover, we are using Gabor and Gauss-Laguerre filter banks applied on the input image data that yield to 12 resulting feature vectors. Each representation is compared with corresponding counterpart from the biometric database. We also add the recognition based on the iso-geodesic curves. The final score-level fusion is performed on 13 comparison scores using the Support Vector Machine (SVM) classifier.

  17. An efficient solid modeling system based on a hand-held 3D laser scan device

    NASA Astrophysics Data System (ADS)

    Xiong, Hanwei; Xu, Jun; Xu, Chenxi; Pan, Ming

    2014-12-01

    The hand-held 3D laser scanner sold in the market is appealing for its port and convenient to use, but price is expensive. To develop such a system based cheap devices using the same principles as the commercial systems is impossible. In this paper, a simple hand-held 3D laser scanner is developed based on a volume reconstruction method using cheap devices. Unlike convenient laser scanner to collect point cloud of an object surface, the proposed method only scan few key profile curves on the surface. Planar section curve network can be generated from these profile curves to construct a volume model of the object. The details of design are presented, and illustrated by the example of a complex shaped object.

  18. Model-based 3D/2D deformable registration of MR images.

    PubMed

    Marami, Bahram; Sirouspour, Shahin; Capson, David W

    2011-01-01

    A method is proposed for automatic registration of 3D preoperative magnetic resonance images of deformable tissue to a sequence of its 2D intraoperative images. The algorithm employs a dynamic continuum mechanics model of the deformation and similarity (distance) measures such as correlation ratio, mutual information or sum of squared differences for registration. The registration is solely based on information present in the 3D preoperative and 2D intraoperative images and does not require fiducial markers, feature extraction or image segmentation. Results of experiments with a biopsy training breast phantom show that the proposed method can perform well in the presence of large deformations. This is particularly useful for clinical applications such as MR-based breast biopsy where large tissue deformations occur.

  19. A web-based solution for 3D medical image visualization

    NASA Astrophysics Data System (ADS)

    Hou, Xiaoshuai; Sun, Jianyong; Zhang, Jianguo

    2015-03-01

    In this presentation, we present a web-based 3D medical image visualization solution which enables interactive large medical image data processing and visualization over the web platform. To improve the efficiency of our solution, we adopt GPU accelerated techniques to process images on the server side while rapidly transferring images to the HTML5 supported web browser on the client side. Compared to traditional local visualization solution, our solution doesn't require the users to install extra software or download the whole volume dataset from PACS server. By designing this web-based solution, it is feasible for users to access the 3D medical image visualization service wherever the internet is available.

  20. 3D-modeling of deformed halite hopper crystals by Object Based Image Analysis

    NASA Astrophysics Data System (ADS)

    Leitner, Christoph; Hofmann, Peter; Marschallinger, Robert

    2014-12-01

    Object Based Image Analysis (OBIA) is an established method for analyzing multiscale and multidimensional imagery in a range of disciplines. In the present study this method was used for the 3D reconstruction of halite hopper crystals in a mudrock sample, based on Computed Tomography data. To quantitatively assess the reliability of OBIA results, they were benchmarked against a corresponding "gold standard", a reference 3D model of the halite crystals that was derived by manual expert digitization of the CT images. For accuracy assessment, classical per-scene statistics were extended to per-object statistics. The strength of OBIA was to recognize all objects similar to halite hopper crystals and in particular to eliminate cracks. Using a support vector machine (SVM) classifier on top of OBIA, unsuitable objects like halite crystal clusters, polyhalite-coated crystals and spherical halite crystals were effectively dismissed, but simultaneously the number of well-shaped halites was reduced.

  1. Effectiveness Evaluation of Force Protection Training Using Computer-Based Instruction and X3d Simulation

    DTIC Science & Technology

    2007-09-01

    to growing operational constraints accelerated by the Global War on Terror, the United States Navy is looking for alternative methods of training to...accomplished efficiently and effectively, saving the U.S. Navy time and resources while maintaining a high state of readiness. The goal of this thesis is...COMPUTER-BASED INSTRUCTION AND X3D SIMULATION Wilfredo Cruzbaez Lieutenant, United States Navy B.A., Norfolk State University, 2001 Submitted in

  2. Correlation-based discrimination between cardiac tissue and blood for segmentation of 3D echocardiographic images

    NASA Astrophysics Data System (ADS)

    Saris, Anne E. C. M.; Nillesen, Maartje M.; Lopata, Richard G. P.; de Korte, Chris L.

    2013-03-01

    Automated segmentation of 3D echocardiographic images in patients with congenital heart disease is challenging, because the boundary between blood and cardiac tissue is poorly defined in some regions. Cardiologists mentally incorporate movement of the heart, using temporal coherence of structures to resolve ambiguities. Therefore, we investigated the merit of temporal cross-correlation for automated segmentation over the entire cardiac cycle. Optimal settings for maximum cross-correlation (MCC) calculation, based on a 3D cross-correlation based displacement estimation algorithm, were determined to obtain the best contrast between blood and myocardial tissue over the entire cardiac cycle. Resulting envelope-based as well as RF-based MCC values were used as additional external force in a deformable model approach, to segment the left-ventricular cavity in entire systolic phase. MCC values were tested against, and combined with, adaptive filtered, demodulated RF-data. Segmentation results were compared with manually segmented volumes using a 3D Dice Similarity Index (3DSI). Results in 3D pediatric echocardiographic images sequences (n = 4) demonstrate that incorporation of temporal information improves segmentation. The use of MCC values, either alone or in combination with adaptive filtered, demodulated RF-data, resulted in an increase of the 3DSI in 75% of the cases (average 3DSI increase: 0.71 to 0.82). Results might be further improved by optimizing MCC-contrast locally, in regions with low blood-tissue contrast. Reducing underestimation of the endocardial volume due to MCC processing scheme (choice of window size) and consequential border-misalignment, could also lead to more accurate segmentations. Furthermore, increasing the frame rate will also increase MCC-contrast and thus improve segmentation.

  3. Active illumination based 3D surface reconstruction and registration for image guided medialization laryngoplasty

    NASA Astrophysics Data System (ADS)

    Jin, Ge; Lee, Sang-Joon; Hahn, James K.; Bielamowicz, Steven; Mittal, Rajat; Walsh, Raymond

    2007-03-01

    The medialization laryngoplasty is a surgical procedure to improve the voice function of the patient with vocal fold paresis and paralysis. An image guided system for the medialization laryngoplasty will help the surgeons to accurately place the implant and thus reduce the failure rates of the surgery. One of the fundamental challenges in image guided system is to accurately register the preoperative radiological data to the intraoperative anatomical structure of the patient. In this paper, we present a combined surface and fiducial based registration method to register the preoperative 3D CT data to the intraoperative surface of larynx. To accurately model the exposed surface area, a structured light based stereo vision technique is used for the surface reconstruction. We combined the gray code pattern and multi-line shifting to generate the intraoperative surface of the larynx. To register the point clouds from the intraoperative stage to the preoperative 3D CT data, a shape priori based ICP method is proposed to quickly register the two surfaces. The proposed approach is capable of tracking the fiducial markers and reconstructing the surface of larynx with no damage to the anatomical structure. We used off-the-shelf digital cameras, LCD projector and rapid 3D prototyper to develop our experimental system. The final RMS error in the registration is less than 1mm.

  4. Development of biologically active compounds by combining 3D QSAR and structure-based design methods

    NASA Astrophysics Data System (ADS)

    Sippl, Wolfgang

    2002-11-01

    One of the major challenges in computational approaches to drug design is the accurate prediction of the binding affinity of novel biomolecules. In the present study an automated procedure which combines docking and 3D-QSAR methods was applied to several drug targets. The developed receptor-based 3D-QSAR methodology was tested on several sets of ligands for which the three-dimensional structure of the target protein has been solved - namely estrogen receptor, acetylcholine esterase and protein-tyrosine-phosphatase 1B. The molecular alignments of the studied ligands were determined using the docking program AutoDock and were compared with the X-ray structures of the corresponding protein-ligand complexes. The automatically generated protein-based ligand alignment obtained was subsequently taken as basis for a comparative field analysis applying the GRID/GOLPE approach. Using GRID interaction fields and applying variable selection procedures, highly predictive models were obtained. It is expected that concepts from receptor-based 3D QSAR will be valuable tools for the analysis of high-throughput screening as well as virtual screening data

  5. Laboratory-based x-ray phase-contrast tomography enables 3D virtual histology

    NASA Astrophysics Data System (ADS)

    Töpperwien, Mareike; Krenkel, Martin; Quade, Felix; Salditt, Tim

    2016-09-01

    Due to the large penetration depth and small wavelength hard x-rays offer a unique potential for 3D biomedical and biological imaging, combining capabilities of high resolution and large sample volume. However, in classical absorption-based computed tomography, soft tissue only shows a weak contrast, limiting the actual resolution. With the advent of phase-contrast methods, the much stronger phase shift induced by the sample can now be exploited. For high resolution, free space propagation behind the sample is particularly well suited to make the phase shift visible. Contrast formation is based on the self-interference of the transmitted beam, resulting in object-induced intensity modulations in the detector plane. As this method requires a sufficiently high degree of spatial coherence, it was since long perceived as a synchrotron-based imaging technique. In this contribution we show that by combination of high brightness liquid-metal jet microfocus sources and suitable sample preparation techniques, as well as optimized geometry, detection and phase retrieval, excellent three-dimensional image quality can be obtained, revealing the anatomy of a cobweb spider in high detail. This opens up new opportunities for 3D virtual histology of small organisms. Importantly, the image quality is finally augmented to a level accessible to automatic 3D segmentation.

  6. A broadly applicable 3-D neuron tracing method based on open-curve snake.

    PubMed

    Wang, Yu; Narayanaswamy, Arunachalam; Tsai, Chia-Ling; Roysam, Badrinath

    2011-09-01

    This paper presents a broadly applicable algorithm and a comprehensive open-source software implementation for automated tracing of neuronal structures in 3-D microscopy images. The core 3-D neuron tracing algorithm is based on three-dimensional (3-D) open-curve active Contour (Snake). It is initiated from a set of automatically detected seed points. Its evolution is driven by a combination of deforming forces based on the Gradient Vector Flow (GVF), stretching forces based on estimation of the fiber orientations, and a set of control rules. In this tracing model, bifurcation points are detected implicitly as points where multiple snakes collide. A boundariness measure is employed to allow local radius estimation. A suite of pre-processing algorithms enable the system to accommodate diverse neuronal image datasets by reducing them to a common image format. The above algorithms form the basis for a comprehensive, scalable, and efficient software system developed for confocal or brightfield images. It provides multiple automated tracing modes. The user can optionally interact with the tracing system using multiple view visualization, and exercise full control to ensure a high quality reconstruction. We illustrate the utility of this tracing system by presenting results from a synthetic dataset, a brightfield dataset and two confocal datasets from the DIADEM challenge.

  7. Wavelet Based Feature Extraction for Target Recognition and Minefield Detection

    DTIC Science & Technology

    2007-11-02

    with Ron Gross (NSWC); presentation of course "Wavelets and Filter Banks " to NSWC personnel; application of simulated annealing to optimize RF absorption...characteristics of multilayer surfaces; generalization of wavelet transform to M-band wavelets; algorithm to generate a wavelet filter bank using any...filter whatsoever as the analysis filter; implementation of an algorithm to parameterize all M-band paraunitary filter banks .

  8. Combining scale-space and similarity-based aspect graphs for fast 3D object recognition.

    PubMed

    Ulrich, Markus; Wiedemann, Christian; Steger, Carsten

    2012-10-01

    This paper describes an approach for recognizing instances of a 3D object in a single camera image and for determining their 3D poses. A hierarchical model is generated solely based on the geometry information of a 3D CAD model of the object. The approach does not rely on texture or reflectance information of the object's surface, making it useful for a wide range of industrial and robotic applications, e.g., bin-picking. A hierarchical view-based approach that addresses typical problems of previous methods is applied: It handles true perspective, is robust to noise, occlusions, and clutter to an extent that is sufficient for many practical applications, and is invariant to contrast changes. For the generation of this hierarchical model, a new model image generation technique by which scale-space effects can be taken into account is presented. The necessary object views are derived using a similarity-based aspect graph. The high robustness of an exhaustive search is combined with an efficient hierarchical search. The 3D pose is refined by using a least-squares adjustment that minimizes geometric distances in the image, yielding a position accuracy of up to 0.12 percent with respect to the object distance, and an orientation accuracy of up to 0.35 degree in our tests. The recognition time is largely independent of the complexity of the object, but depends mainly on the range of poses within which the object may appear in front of the camera. For efficiency reasons, the approach allows the restriction of the pose range depending on the application. Typical runtimes are in the range of a few hundred ms.

  9. 3-D ultrasonic strain imaging based on a linear scanning system.

    PubMed

    Huang, Qinghua; Xie, Bo; Ye, Pengfei; Chen, Zhaohong

    2015-02-01

    This paper introduces a 3-D strain imaging method based on a freehand linear scanning mode. We designed a linear sliding track with a position sensor and a height-adjustable holder to constrain the movement of an ultrasound probe in a freehand manner. When moving the probe along the sliding track, the corresponding positional measures for the probe are transmitted via a wireless communication module based on Bluetooth in real time. In a single examination, the probe is scanned in two sweeps in which the height of the probe is adjusted by the holder to collect the pre- and postcompression radio-frequency echoes, respectively. To generate a 3-D strain image, a volume cubic in which the voxels denote relative strains for tissues is defined according to the range of the two sweeps. With respect to the post-compression frames, several slices in the volume are determined and the pre-compression frames are re-sampled to precisely correspond to the post-compression frames. Thereby, a strain estimation method based on minimizing a cost function using dynamic programming is used to obtain the 2-D strain image for each pair of frames from the re-sampled pre-compression sweep and the post-compression sweep, respectively. A software system is developed for volume reconstruction, visualization, and measurement of the 3-D strain images. The experimental results show that high-quality 3-D strain images of phantom and human tissues can be generated by the proposed method, indicating that the proposed system can be applied for real clinical applications (e.g., musculoskeletal assessments).

  10. MO-FG-303-03: Demonstration of Universal Knowledge-Based 3D Dose Prediction

    SciTech Connect

    Shiraishi, S; Moore, K L

    2015-06-15

    Purpose: To demonstrate a knowledge-based 3D dose prediction methodology that can accurately predict achievable radiotherapy distributions. Methods: Using previously treated plans as input, an artificial neural network (ANN) was trained to predict 3D dose distributions based on 14 patient-specific anatomical parameters including the distance (r) to planning target volume (PTV) boundary, organ-at-risk (OAR) boundary distances, and angular position ( θ,φ). 23 prostate and 49 stereotactic radiosurgery (SRS) cases with ≥1 nearby OARs were studied. All were planned with volumetric-modulated arc therapy (VMAT) to prescription doses of 81Gy for prostate and 12–30Gy for SRS. Site-specific ANNs were trained using all prostate 23 plans and using a 24 randomly-selected subset for the SRS model. The remaining 25 SRS plans were used to validate the model. To quantify predictive accuracy, the dose difference between the clinical plan and prediction were calculated on a voxel-by-voxel basis δD(r,θ,φ)=Dclin(r,θ,φ)-Dpred(r, θ,φ). Grouping voxels by boundary distance, the mean <δ Dr>=(1/N)Σ -θ,φ D(r,θ,φ) and inter-quartile range (IQR) quantified the accuracy of this method for deriving DVH estimations. The standard deviation (σ) of δ D quantified the 3D dose prediction error on a voxel-by-voxel basis. Results: The ANNs were highly accurate in predictive ability for both prostate and SRS plans. For prostate, <δDr> ranged from −0.8% to +0.6% (max IQR=3.8%) over r=0–32mm, while 3D dose prediction accuracy averaged from σ=5–8% across the same range. For SRS, from r=0–34mm the training set <δDr> ranged from −3.7% to +1.5% (max IQR=4.4%) while the validation set <δDr> ranged from −2.2% to +5.8% (max IQR=5.3%). 3D dose prediction accuracy averaged σ=2.5% for the training set and σ=4.0% over the same interval. Conclusion: The study demonstrates this technique’s ability to predict achievable 3D dose distributions for VMAT SRS and prostate. Future

  11. Pipeline inwall 3D measurement system based on the cross structured light

    NASA Astrophysics Data System (ADS)

    Shen, Da; Lin, Zhipeng; Xue, Lei; Zheng, Qiang; Wang, Zichi

    2014-01-01

    In order to accurately realize the defect detection of pipeline inwall, this paper proposes a measurement system made up of cross structured light, single CCD camera and a smart car, etc. Based on structured light measurement technology, this paper mainly introduces the structured light measurement system, the imaging mathematical model, and the parameters and method of camera calibration. Using these measuring principles and methods, the camera in remote control car platform achieves continuous shooting of objects and real-time rebound processing as well as utilizing established model to extract 3D point cloud coordinate to reconstruct pipeline defects, so it is possible to achieve 3D automatic measuring, and verifies the correctness and feasibility of this system. It has been found that this system has great measurement accuracy in practice.

  12. Dextran-based hydrogel formed by thiol-Michael addition reaction for 3D cell encapsulation.

    PubMed

    Liu, Zhen Qi; Wei, Zhao; Zhu, Xv Long; Huang, Guo You; Xu, Feng; Yang, Jian Hai; Osada, Yoshihito; Zrínyi, Miklós; Li, Jian Hui; Chen, Yong Mei

    2015-04-01

    Cell encapsulation in three-dimensional (3D) hydrogels can mimic native cell microenvironment and plays a major role in cell-based transplantation therapies. In this contribution, a novel in situ-forming hydrogel, Dex-l-DTT hydrogel ("l" means "linked-by"), by cross-linking glycidyl methacrylate derivatized dextran (Dex-GMA) and dithiothreitol (DTT) under physiological conditions, has been developed using thiol-Michael addition reaction. The mechanical properties, gelation process and degree of swelling of the hydrogel can be easily adjusted by changing the pH of phosphate buffer saline. The 3D cell encapsulation ability is demonstrated by encapsulating rat bone marrow mesenchymal stem cells (BMSCs) and NIH/3T3 fibroblasts into the in situ-forming hydrogel with maintained high viability. The BMSCs also maintain their differentiation potential after encapsulation. These results demonstrate that the Dex-l-DTT hydrogel holds great potential for biomedical field.

  13. Quantum dot based immunosensor using 3D circular microchannels fabricated in PDMS.

    PubMed

    Morarka, Amit; Agrawal, Shailaja; Kale, Sonia; Kale, Anup; Ogale, Satish; Paknikar, Kishore; Bodas, Dhananjay

    2011-02-15

    Microchannel is basic functional component of microfluidic chip and every step-forward of its construction technique has been receiving concern all over the world. The present work describes a novel, rapid and simple fabrication technique for building 3D microchannels in poly(dimethyl siloxane) (PDMS) elastomer. These microchannels were used for rapid detection of antigens (E. coli) by quantum dot (QD) based approach. Luminescent QD (CdTe) were synthesized by aqueous method and characterized using high resolution transmission electron microscopy (HRTEM), fluorescence spectroscopy and X-ray diffraction (XRD). The QDs were functionalized with anti-E. coli antibodies for immuno-detection. The reported process allowed easier and faster method of fabrication of circular 3D micochannels and demonstrated their potential use in an immuno-biosensor device.

  14. Excitation of anti-symmetric coupled spoof SPPs in 3D SIS waveguides based on coupling

    NASA Astrophysics Data System (ADS)

    Li-li, Tian; Yang, Chen; Jian-long, Liu; Kai, Guo; Ke-ya, Zhou; Yang, Gao; Shu-tian, Liu

    2016-07-01

    According to the electromagnetic field distributions, there exist two kinds of coupled spoof surface plasmon polaritons (SSPPs), the symmetric and anti-symmetric modes, in the three-dimensional (3D) subwavelength spoof-insulator-spoof (SIS) waveguide. We study the dispersion and excitation of the two kinds of coupled SSPPs supported by the 3D SIS waveguide. The evolution of the dispersion with the thickness and gap width of the waveguide is numerically investigated, and we give a theoretical analysis according to the coupling mechanism. Specially, based on the coupling mechanism, we design a zipper structure, through which the excitation and propagation of the anti-symmetric coupled modes can be realized effectively. Project supported by the National Basic Research Program of China (Grant No. 2013CBA01702) and the National Natural Science Foundation of China (Grant Nos. 61377016, 61575055, 10974039, 61307072, 61308017, and 61405056).

  15. M-OTDR sensing system based on 3D encoded microstructures

    PubMed Central

    Sun, Qizhen; Ai, Fan; Liu, Deming; Cheng, Jianwei; Luo, Hongbo; Peng, Kuan; Luo, Yiyang; Yan, Zhijun; Shum, Perry Ping

    2017-01-01

    In this work, a quasi-distributed sensing scheme named as microstructured OTDR (M-OTDR) by introducing ultra-weak microstructures along the fiber is proposed. Owing to its relative higher reflectivity compared with the backscattered coefficient in fiber and three dimensional (3D) i.e. wavelength/frequency/time encoded property, the M-OTDR system exhibits the superiorities of high signal to noise ratio (SNR), high spatial resolution of millimeter level and high multiplexing capacity up to several ten thousands theoretically. A proof-of-concept system consisting of 64 sensing units is constructed to demonstrate the feasibility and sensing performance. With the help of the demodulation method based on 3D analysis and spectrum reconstruction of the signal light, quasi-distributed temperature sensing with a spatial resolution of 20 cm as well as a measurement resolution of 0.1 °C is realized. PMID:28106132

  16. Synesthetic art through 3-D projection: The requirements of a computer-based supermedium

    NASA Technical Reports Server (NTRS)

    Mallary, Robert

    1989-01-01

    A computer-based form of multimedia art is proposed that uses the computer to fuse aspects of painting, sculpture, dance, music, film, and other media into a one-to-one synthesia of image and sound for spatially synchronous 3-D projection. Called synesthetic art, this conversion of many varied media into an aesthetically unitary experience determines the character and requirements of the system and its software. During the start-up phase, computer stereographic systems are unsuitable for software development. Eventually, a new type of illusory-projective supermedium will be required to achieve the needed combination of large-format projection and convincing real life presence, and to handle the vast amount of 3-D visual and acoustic information required. The influence of the concept on the author's research and creative work is illustrated through two examples.

  17. The solar silicon abundance based on 3D non-LTE calculations

    NASA Astrophysics Data System (ADS)

    Amarsi, A. M.; Asplund, M.

    2017-01-01

    We present 3D non-local thermodynamic equilibrium (non-LTE) radiative transfer calculations for silicon in the solar photosphere, using an extensive model atom that includes recent, realistic neutral hydrogen collisional cross-sections. We find that photon losses in the Si I lines give rise to slightly negative non-LTE abundance corrections of the order of -0.01 dex. We infer a 3D non-LTE-based solar silicon abundance of lg ɛ_{Si{⊙}}=7.51 dex. With silicon commonly chosen to be the anchor between the photospheric and meteoritic abundances, we find that the meteoritic abundance scale remains unchanged compared with the Asplund et al. and Lodders et al. results.

  18. Quasimodes instability analysis of uncertain asymmetric rotor system based on 3D solid element model

    NASA Astrophysics Data System (ADS)

    Zuo, Yanfei; Wang, Jianjun; Ma, Weimeng

    2017-03-01

    Uncertainties are considered in the equation of motion of an asymmetric rotor system. Based on Hill's determinant method, quasimodes stability analysis with uncertain parameters is used to get stochastic boundaries of unstable regions. Firstly, A 3D finite element rotor model was built in rotating frame with four parameterized coefficients, which is assumed as random parameters representing the uncertainties existing in the rotor system. Then the influences of uncertain coefficients on the distribution of the unstable region boundaries are analyzed. The results show that uncertain parameters have various influences on the size, boundary and number of unstable regions. At last, the statistic results of the minimum and maximum spin speeds of unstable regions were got by Monte Carlo simulation. The used method is suitable for real engineering rotor system, because arbitrary configuration of rotors can be modeled by 3D finite element.

  19. Internet2-based 3D PET image reconstruction using a PC cluster

    NASA Astrophysics Data System (ADS)

    Shattuck, D. W.; Rapela, J.; Asma, E.; Chatzioannou, A.; Qi, J.; Leahy, R. M.

    2002-08-01

    We describe an approach to fast iterative reconstruction from fully three-dimensional (3D) PET data using a network of PentiumIII PCs configured as a Beowulf cluster. To facilitate the use of this system, we have developed a browser-based interface using Java. The system compresses PET data on the user's machine, sends these data over a network, and instructs the PC cluster to reconstruct the image. The cluster implements a parallelized version of our preconditioned conjugate gradient method for fully 3D MAP image reconstruction. We report on the speed-up factors using the Beowulf approach and the impacts of communication latencies in the local cluster network and the network connection between the user's machine and our PC cluster.

  20. Internet2-based 3D PET image reconstruction using a PC cluster.

    PubMed

    Shattuck, D W; Rapela, J; Asma, E; Chatzioannou, A; Qi, J; Leahy, R M

    2002-08-07

    We describe an approach to fast iterative reconstruction from fully three-dimensional (3D) PET data using a network of PentiumIII PCs configured as a Beowulf cluster. To facilitate the use of this system, we have developed a browser-based interface using Java. The system compresses PET data on the user's machine, sends these data over a network, and instructs the PC cluster to reconstruct the image. The cluster implements a parallelized version of our preconditioned conjugate gradient method for fully 3D MAP image reconstruction. We report on the speed-up factors using the Beowulf approach and the impacts of communication latencies in the local cluster network and the network connection between the user's machine and our PC cluster.

  1. Multi-view indoor human behavior recognition based on 3D skeleton

    NASA Astrophysics Data System (ADS)

    Peng, Ling; Lu, Tongwei; Min, Feng

    2015-12-01

    For the problems caused by viewpoint changes in activity recognition, a multi-view interior human behavior recognition method based on 3D framework is presented. First, Microsoft's Kinect device is used to obtain body motion video in the positive perspective, the oblique angle and the side perspective. Second, it extracts bone joints and get global human features and the local features of arms and legs at the same time to form 3D skeletal features set. Third, online dictionary learning on feature set is used to reduce the dimension of feature. Finally, linear support vector machine (LSVM) is used to obtain the results of behavior recognition. The experimental results show that this method has better recognition rate.

  2. A web-based 3D visualisation and assessment system for urban precinct scenario modelling

    NASA Astrophysics Data System (ADS)

    Trubka, Roman; Glackin, Stephen; Lade, Oliver; Pettit, Chris

    2016-07-01

    Recent years have seen an increasing number of spatial tools and technologies for enabling better decision-making in the urban environment. They have largely arisen because of the need for cities to be more efficiently planned to accommodate growing populations while mitigating urban sprawl, and also because of innovations in rendering data in 3D being well suited for visualising the urban built environment. In this paper we review a number of systems that are better known and more commonly used in the field of urban planning. We then introduce Envision Scenario Planner (ESP), a web-based 3D precinct geodesign, visualisation and assessment tool, developed using Agile and Co-design methods. We provide a comprehensive account of the tool, beginning with a discussion of its design and development process and concluding with an example use case and a discussion of the lessons learned in its development.

  3. Tunable fluorescence enhancement based on bandgap-adjustable 3D Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Hu, Fei; Gao, Suning; Zhu, Lili; Liao, Fan; Yang, Lulu; Shao, Mingwang

    2016-06-01

    Great progress has been made in fluorescence-based detection utilizing solid state enhanced substrates in recent years. However, it is still difficult to achieve reliable substrates with tunable enhancement factors. The present work shows liquid fluorescence enhanced substrates consisting of suspensions of Fe3O4 nanoparticles (NPs), which can assemble 3D photonic crystal under the external magnetic field. The photonic bandgap induced by the equilibrium of attractive magnetic force and repulsive electrostatic force between adjacent Fe3O4 NPs is utilized to enhance fluorescence intensity of dye molecules (including R6G, RB, Cy5, DMTPS-DCV) in a reversible and controllable manner. The results show that a maximum of 12.3-fold fluorescence enhancement is realized in the 3D Fe3O4 NP substrates without the utilization of metal particles for PCs/DMTPS-DCV (1.0 × 10-7 M, water fraction (f w) = 90%).

  4. Phase-preserving speckle reduction based on soft thresholding in quaternion wavelet domain

    NASA Astrophysics Data System (ADS)

    Liu, Yipeng; Jin, Jing; Wang, Qiang; Shen, Yi

    2012-10-01

    Speckle reduction is a difficult task for ultrasound image processing because of low resolution and contrast. As a novel tool of image analysis, quaternion wavelet (QW) has some superior properties compared to discrete wavelets, such as nearly shift-invariant wavelet coefficients and phase-based texture presentation. We aim to exploit the excellent performance of speckle reduction in quaternion wavelet domain based on the soft thresholding method. First, we exploit the characteristics of magnitude and phases in quaternion wavelet transform (QWT) to the denoising application, and find that the QWT phases of the images are little influenced by the noises. Then we model the QWT magnitude using the Rayleigh distribution, and derive the thresholding criterion. Furthermore, we conduct several experiments on synthetic speckle images and real ultrasound images. The performance of the proposed speckle reduction algorithm, using QWT with soft thresholding, demonstrates superiority to those using discrete wavelet transform and classical algorithms.

  5. Image-based 3D reconstruction and virtual environmental walk-through

    NASA Astrophysics Data System (ADS)

    Sun, Jifeng; Fang, Lixiong; Luo, Ying

    2001-09-01

    We present a 3D reconstruction method, which combines geometry-based modeling, image-based modeling and rendering techniques. The first component is an interactive geometry modeling method which recovery of the basic geometry of the photographed scene. The second component is model-based stereo algorithm. We discus the image processing problems and algorithms of walking through in virtual space, then designs and implement a high performance multi-thread wandering algorithm. The applications range from architectural planning and archaeological reconstruction to virtual environments and cinematic special effects.

  6. Detailed analysis of an optimized FPP-based 3D imaging system

    NASA Astrophysics Data System (ADS)

    Tran, Dat; Thai, Anh; Duong, Kiet; Nguyen, Thanh; Nehmetallah, Georges

    2016-05-01

    In this paper, we present detail analysis and a step-by-step implementation of an optimized fringe projection profilometry (FPP) based 3D shape measurement system. First, we propose a multi-frequency and multi-phase shifting sinusoidal fringe pattern reconstruction approach to increase accuracy and sensitivity of the system. Second, phase error compensation caused by the nonlinear transfer function of the projector and camera is performed through polynomial approximation. Third, phase unwrapping is performed using spatial and temporal techniques and the tradeoff between processing speed and high accuracy is discussed in details. Fourth, generalized camera and system calibration are developed for phase to real world coordinate transformation. The calibration coefficients are estimated accurately using a reference plane and several gauge blocks with precisely known heights and by employing a nonlinear least square fitting method. Fifth, a texture will be attached to the height profile by registering a 2D real photo to the 3D height map. The last step is to perform 3D image fusion and registration using an iterative closest point (ICP) algorithm for a full field of view reconstruction. The system is experimentally constructed using compact, portable, and low cost off-the-shelf components. A MATLAB® based GUI is developed to control and synchronize the whole system.

  7. Obstacle avoidance using predictive vision based on a dynamic 3D world model

    NASA Astrophysics Data System (ADS)

    Benjamin, D. Paul; Lyons, Damian; Achtemichuk, Tom

    2006-10-01

    We have designed and implemented a fast predictive vision system for a mobile robot based on the principles of active vision. This vision system is part of a larger project to design a comprehensive cognitive architecture for mobile robotics. The vision system represents the robot's environment with a dynamic 3D world model based on a 3D gaming platform (Ogre3D). This world model contains a virtual copy of the robot and its environment, and outputs graphics showing what the virtual robot "sees" in the virtual world; this is what the real robot expects to see in the real world. The vision system compares this output in real time with the visual data. Any large discrepancies are flagged and sent to the robot's cognitive system, which constructs a plan for focusing on the discrepancies and resolving them, e.g. by updating the position of an object or by recognizing a new object. An object is recognized only once; thereafter its observed data are monitored for consistency with the predictions, greatly reducing the cost of scene understanding. We describe the implementation of this vision system and how the robot uses it to locate and avoid obstacles.

  8. Low-cost impact detection and location for automated inspections of 3D metallic based structures.

    PubMed

    Morón, Carlos; Portilla, Marina P; Somolinos, José A; Morales, Rafael

    2015-05-28

    This paper describes a new low-cost means to detect and locate mechanical impacts (collisions) on a 3D metal-based structure. We employ the simple and reasonably hypothesis that the use of a homogeneous material will allow certain details of the impact to be automatically determined by measuring the time delays of acoustic wave propagation throughout the 3D structure. The location of strategic piezoelectric sensors on the structure and an electronic-computerized system has allowed us to determine the instant and position at which the impact is produced. The proposed automatic system allows us to fully integrate impact point detection and the task of inspecting the point or zone at which this impact occurs. What is more, the proposed method can be easily integrated into a robot-based inspection system capable of moving over 3D metallic structures, thus avoiding (or minimizing) the need for direct human intervention. Experimental results are provided to show the effectiveness of the proposed approach.

  9. Color influence on accuracy of 3D scanners based on structured light

    NASA Astrophysics Data System (ADS)

    Voisin, Sophie; Page, David L.; Foufou, Sebti; Truchetet, Frédéric; Abidi, Mongi A.

    2006-02-01

    The characterization of commercial 3D scanners allows acquiring precise and useful data. The accuracy of range and, more recently, color for 3D scanners is usually studied separately, but when the 3D scanner is based on structured light with a color coding pattern, color influence on range accuracy should be investigated. The commercial product that we have tested has the particularity that it can acquire data under ambient light instead of a controlled environment as it is with most available scanners. Therefore, based on related work in the literature and on experiments we have done on a variety of standard illuminants, we have designed an interesting setup to control illuminant interference. Basically, the setup consists of acquiring the well-known Macbeth ColorChecker under a controlled environment and also ambient daylight. The results have shown variations with respect to the color. We have performed several statistical studies to show how the range results evolve with respect to the RGB and the HSV channels. In addition, a systematic noise error has also been identified. This noise depends on the object color. A subset of colors shows strong noise errors while other colors have minimal or even no systematic error under the same illuminant.

  10. Evolution in boron-based GEM detectors for diffraction measurements: from planar to 3D converters

    NASA Astrophysics Data System (ADS)

    Albani, Giorgia; Perelli Cippo, Enrico; Croci, Gabriele; Muraro, Andrea; Schooneveld, Erik; Scherillo, Antonella; Hall-Wilton, Richard; Kanaki, Kalliopi; Höglund, Carina; Hultman, Lars; Birch, Jens; Claps, Gerardo; Murtas, Fabrizio; Rebai, Marica; Tardocchi, Marco; Gorini, Giuseppe

    2016-11-01

    The so-called ‘3He-crisis’ has motivated the neutron detector community to undertake an intense R&D programme in order to develop technologies alternative to standard 3He tubes and suitable for neutron detection systems in future spallation sources such as the European spallation source (ESS). Boron-based GEM (gas electron multiplier) detectors are a promising ‘3He-free’ technology for thermal neutron detection in neutron scattering experiments. In this paper the evolution of boron-based GEM detectors from planar to 3D converters with an application in diffraction measurements is presented. The use of 3D converters coupled with GEMs allows for an optimization of the detector performances. Three different detectors were used for diffraction measurements on the INES instrument at the ISIS spallation source. The performances of the GEM-detectors are compared with those of conventional 3He tubes installed on the INES instrument. The conceptual detector with the 3D converter used in this paper reached a count rate per unit area of about 25% relative to the currently installed 3He tube. Its timing resolution is similar and the signal-to-background ratio (S/B) is 2 times lower.

  11. Low-Cost Impact Detection and Location for Automated Inspections of 3D Metallic Based Structures

    PubMed Central

    Morón, Carlos; Portilla, Marina P.; Somolinos, José A.; Morales, Rafael

    2015-01-01

    This paper describes a new low-cost means to detect and locate mechanical impacts (collisions) on a 3D metal-based structure. We employ the simple and reasonably hypothesis that the use of a homogeneous material will allow certain details of the impact to be automatically determined by measuring the time delays of acoustic wave propagation throughout the 3D structure. The location of strategic piezoelectric sensors on the structure and an electronic-computerized system has allowed us to determine the instant and position at which the impact is produced. The proposed automatic system allows us to fully integrate impact point detection and the task of inspecting the point or zone at which this impact occurs. What is more, the proposed method can be easily integrated into a robot-based inspection system capable of moving over 3D metallic structures, thus avoiding (or minimizing) the need for direct human intervention. Experimental results are provided to show the effectiveness of the proposed approach. PMID:26029951

  12. MO-C-18A-01: Advances in Model-Based 3D Image Reconstruction

    SciTech Connect

    Chen, G; Pan, X; Stayman, J; Samei, E

    2014-06-15

    Recent years have seen the emergence of CT image reconstruction techniques that exploit physical models of the imaging system, photon statistics, and even the patient to achieve improved 3D image quality and/or reduction of radiation dose. With numerous advantages in comparison to conventional 3D filtered backprojection, such techniques bring a variety of challenges as well, including: a demanding computational load associated with sophisticated forward models and iterative optimization methods; nonlinearity and nonstationarity in image quality characteristics; a complex dependency on multiple free parameters; and the need to understand how best to incorporate prior information (including patient-specific prior images) within the reconstruction process. The advantages, however, are even greater – for example: improved image quality; reduced dose; robustness to noise and artifacts; task-specific reconstruction protocols; suitability to novel CT imaging platforms and noncircular orbits; and incorporation of known characteristics of the imager and patient that are conventionally discarded. This symposium features experts in 3D image reconstruction, image quality assessment, and the translation of such methods to emerging clinical applications. Dr. Chen will address novel methods for the incorporation of prior information in 3D and 4D CT reconstruction techniques. Dr. Pan will show recent advances in optimization-based reconstruction that enable potential reduction of dose and sampling requirements. Dr. Stayman will describe a “task-based imaging” approach that leverages models of the imaging system and patient in combination with a specification of the imaging task to optimize both the acquisition and reconstruction process. Dr. Samei will describe the development of methods for image quality assessment in such nonlinear reconstruction techniques and the use of these methods to characterize and optimize image quality and dose in a spectrum of clinical

  13. Image-driven, model-based 3D abdominal motion estimation for MR-guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Stemkens, Bjorn; Tijssen, Rob H. N.; de Senneville, Baudouin Denis; Lagendijk, Jan J. W.; van den Berg, Cornelis A. T.

    2016-07-01

    Respiratory motion introduces substantial uncertainties in abdominal radiotherapy for which traditionally large margins are used. The MR-Linac will open up the opportunity to acquire high resolution MR images just prior to radiation and during treatment. However, volumetric MRI time series are not able to characterize 3D tumor and organ-at-risk motion with sufficient temporal resolution. In this study we propose a method to estimate 3D deformation vector fields (DVFs) with high spatial and temporal resolution based on fast 2D imaging and a subject-specific motion model based on respiratory correlated MRI. In a pre-beam phase, a retrospectively sorted 4D-MRI is acquired, from which the motion is parameterized using a principal component analysis. This motion model is used in combination with fast 2D cine-MR images, which are acquired during radiation, to generate full field-of-view 3D DVFs with a temporal resolution of 476 ms. The geometrical accuracies of the input data (4D-MRI and 2D multi-slice acquisitions) and the fitting procedure were determined using an MR-compatible motion phantom and found to be 1.0-1.5 mm on average. The framework was tested on seven healthy volunteers for both the pancreas and the kidney. The calculated motion was independently validated using one of the 2D slices, with an average error of 1.45 mm. The calculated 3D DVFs can be used retrospectively for treatment simulations, plan evaluations, or to determine the accumulated dose for both the tumor and organs-at-risk on a subject-specific basis in MR-guided radiotherapy.

  14. In vivo bioluminescence tomography based on multi-view projection and 3D surface reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, Shuang; Wang, Kun; Leng, Chengcai; Deng, Kexin; Hu, Yifang; Tian, Jie

    2015-03-01

    Bioluminescence tomography (BLT) is a powerful optical molecular imaging modality, which enables non-invasive realtime in vivo imaging as well as 3D quantitative analysis in preclinical studies. In order to solve the inverse problem and reconstruct inner light sources accurately, the prior structural information is commonly necessary and obtained from computed tomography or magnetic resonance imaging. This strategy requires expensive hybrid imaging system, complicated operation protocol and possible involvement of ionizing radiation. The overall robustness highly depends on the fusion accuracy between the optical and structural information. In this study we present a pure optical bioluminescence tomographic system (POBTS) and a novel BLT method based on multi-view projection acquisition and 3D surface reconstruction. The POBTS acquired a sparse set of white light surface images and bioluminescent images of a mouse. Then the white light images were applied to an approximate surface model to generate a high quality textured 3D surface reconstruction of the mouse. After that we integrated multi-view luminescent images based on the previous reconstruction, and applied an algorithm to calibrate and quantify the surface luminescent flux in 3D.Finally, the internal bioluminescence source reconstruction was achieved with this prior information. A BALB/C mouse with breast tumor of 4T1-fLuc cells mouse model were used to evaluate the performance of the new system and technique. Compared with the conventional hybrid optical-CT approach using the same inverse reconstruction method, the reconstruction accuracy of this technique was improved. The distance error between the actual and reconstructed internal source was decreased by 0.184 mm.

  15. Assessment of Eye Fatigue Caused by 3D Displays Based on Multimodal Measurements

    PubMed Central

    Bang, Jae Won; Heo, Hwan; Choi, Jong-Suk; Park, Kang Ryoung

    2014-01-01

    With the development of 3D displays, user's eye fatigue has been an important issue when viewing these displays. There have been previous studies conducted on eye fatigue related to 3D display use, however, most of these have employed a limited number of modalities for measurements, such as electroencephalograms (EEGs), biomedical signals, and eye responses. In this paper, we propose a new assessment of eye fatigue related to 3D display use based on multimodal measurements. compared to previous works Our research is novel in the following four ways: first, to enhance the accuracy of assessment of eye fatigue, we measure EEG signals, eye blinking rate (BR), facial temperature (FT), and a subjective evaluation (SE) score before and after a user watches a 3D display; second, in order to accurately measure BR in a manner that is convenient for the user, we implement a remote gaze-tracking system using a high speed (mega-pixel) camera that measures eye blinks of both eyes; thirdly, changes in the FT are measured using a remote thermal camera, which can enhance the measurement of eye fatigue, and fourth, we perform various statistical analyses to evaluate the correlation between the EEG signal, eye BR, FT, and the SE score based on the T-test, correlation matrix, and effect size. Results show that the correlation of the SE with other data (FT, BR, and EEG) is the highest, while those of the FT, BR, and EEG with other data are second, third, and fourth highest, respectively. PMID:25192315

  16. Study on Underwater Image Denoising Algorithm Based on Wavelet Transform

    NASA Astrophysics Data System (ADS)

    Jian, Sun; Wen, Wang

    2017-02-01

    This paper analyzes the application of MATLAB in underwater image processing, the transmission characteristics of the underwater laser light signal and the kinds of underwater noise has been described, the common noise suppression algorithm: Wiener filter, median filter, average filter algorithm is brought out. Then the advantages and disadvantages of each algorithm in image sharpness and edge protection areas have been compared. A hybrid filter algorithm based on wavelet transform has been proposed which can be used for Color Image Denoising. At last the PSNR and NMSE of each algorithm has been given out, which compares the ability to de-noising

  17. Wavelet Transform of Super-Resolutions Based on Radar and Infrared Sensor Fusion

    DTIC Science & Technology

    1998-05-01

    0I Q’UAL1 INwPO¶= I VI STATEMB r AApproved for public release; Distribution Unlimited NAVY CASE 77545 WAVELET TRANSFORM OF SUPER-RESOLUTIONS BASED ON...INVENTION It is, therefore, an object of the present invention to provide a structure and method for applying the forward and reverse Wavelet Transform (WT...invention, the noisy super- 10 resolution of infrared imaging is combined with the Wavelet transform for radar corner back-scattering size information

  18. Robust object tracking techniques for vision-based 3D motion analysis applications

    NASA Astrophysics Data System (ADS)

    Knyaz, Vladimir A.; Zheltov, Sergey Y.; Vishnyakov, Boris V.

    2016-04-01

    Automated and accurate spatial motion capturing of an object is necessary for a wide variety of applications including industry and science, virtual reality and movie, medicine and sports. For the most part of applications a reliability and an accuracy of the data obtained as well as convenience for a user are the main characteristics defining the quality of the motion capture system. Among the existing systems for 3D data acquisition, based on different physical principles (accelerometry, magnetometry, time-of-flight, vision-based), optical motion capture systems have a set of advantages such as high speed of acquisition, potential for high accuracy and automation based on advanced image processing algorithms. For vision-based motion capture accurate and robust object features detecting and tracking through the video sequence are the key elements along with a level of automation of capturing process. So for providing high accuracy of obtained spatial data the developed vision-based motion capture system "Mosca" is based on photogrammetric principles of 3D measurements and supports high speed image acquisition in synchronized mode. It includes from 2 to 4 technical vision cameras for capturing video sequences of object motion. The original camera calibration and external orientation procedures provide the basis for high accuracy of 3D measurements. A set of algorithms as for detecting, identifying and tracking of similar targets, so for marker-less object motion capture is developed and tested. The results of algorithms' evaluation show high robustness and high reliability for various motion analysis tasks in technical and biomechanics applications.

  19. Context-adaptive based CU processing for 3D-HEVC

    PubMed Central

    Shen, Liquan; An, Ping; Liu, Zhi

    2017-01-01

    The 3D High Efficiency Video Coding (3D-HEVC) standard aims to code 3D videos that usually contain multi-view texture videos and its corresponding depth information. It inherits the same quadtree prediction structure of HEVC to code both texture videos and depth maps. Each coding unit (CU) allows recursively splitting into four equal sub-CUs. At each CU depth level, it enables 10 types of inter modes and 35 types of intra modes in inter frames. Furthermore, the inter-view prediction tools are applied to each view in the test model of 3D-HEVC (HTM), which uses variable size disparity-compensated prediction to exploit inter-view correlation within neighbor views. It also exploits redundancies between a texture video and its associated depth using inter-component coding tools. These achieve the highest coding efficiency to code 3D videos but require a very high computational complexity. In this paper, we propose a context-adaptive based fast CU processing algorithm to jointly optimize the most complex components of HTM including CU depth level decision, mode decision, motion estimation (ME) and disparity estimation (DE) processes. It is based on the hypothesis that the optimal CU depth level, prediction mode and motion vector of a CU are correlated with those from spatiotemporal, inter-view and inter-component neighboring CUs. We analyze the video content based on coding information from neighboring CUs and early predict each CU into one of five categories i.e., DE-omitted CU, ME-DE-omitted CU, SPLIT CU, Non-SPLIT CU and normal CU, and then each type of CU adaptively adopts different processing strategies. Experimental results show that the proposed algorithm saves 70% encoder runtime on average with only a 0.1% BD-rate increase on coded views and 0.8% BD-rate increase on synthesized views. Our algorithm outperforms the state-of-the-art algorithms in terms of coding time saving or with better RD performance. PMID:28182719

  20. Multi-AUV Target Search Based on Bioinspired Neurodynamics Model in 3-D Underwater Environments.

    PubMed

    Cao, Xiang; Zhu, Daqi; Yang, Simon X

    2016-11-01

    Target search in 3-D underwater environments is a challenge in multiple autonomous underwater vehicles (multi-AUVs) exploration. This paper focuses on an effective strategy for multi-AUV target search in the 3-D underwater environments with obstacles. First, the Dempster-Shafer theory of evidence is applied to extract information of environment from the sonar data to build a grid map of the underwater environments. Second, a topologically organized bioinspired neurodynamics model based on the grid map is constructed to represent the dynamic environment. The target globally attracts the AUVs through the dynamic neural activity landscape of the model, while the obstacles locally push the AUVs away to avoid collision. Finally, the AUVs plan their search path to the targets autonomously by a steepest gradient descent rule. The proposed algorithm deals with various situations, such as static targets search, dynamic targets search, and one or several AUVs break down in the 3-D underwater environments with obstacles. The simulation results show that the proposed algorithm is capable of guiding multi-AUV to achieve search task of multiple targets with higher efficiency and adaptability compared with other algorithms.

  1. Random Walk Based Segmentation for the Prostate on 3D Transrectal Ultrasound Images.

    PubMed

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Nieh, Peter T; Master, Viraj V; Schuster, David M; Fei, Baowei

    2016-02-27

    This paper proposes a new semi-automatic segmentation method for the prostate on 3D transrectal ultrasound images (TRUS) by combining the region and classification information. We use a random walk algorithm to express the region information efficiently and flexibly because it can avoid segmentation leakage and shrinking bias. We further use the decision tree as the classifier to distinguish the prostate from the non-prostate tissue because of its fast speed and superior performance, especially for a binary classification problem. Our segmentation algorithm is initialized with the user roughly marking the prostate and non-prostate points on the mid-gland slice which are fitted into an ellipse for obtaining more points. Based on these fitted seed points, we run the random walk algorithm to segment the prostate on the mid-gland slice. The segmented contour and the information from the decision tree classification are combined to determine the initial seed points for the other slices. The random walk algorithm is then used to segment the prostate on the adjacent slice. We propagate the process until all slices are segmented. The segmentation method was tested in 32 3D transrectal ultrasound images. Manual segmentation by a radiologist serves as the gold standard for the validation. The experimental results show that the proposed method achieved a Dice similarity coefficient of 91.37±0.05%. The segmentation method can be applied to 3D ultrasound-guided prostate biopsy and other applications.

  2. Random walk based segmentation for the prostate on 3D transrectal ultrasound images

    NASA Astrophysics Data System (ADS)

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Nieh, Peter T.; Master, Viraj V.; Schuster, David M.; Fei, Baowei

    2016-03-01

    This paper proposes a new semi-automatic segmentation method for the prostate on 3D transrectal ultrasound images (TRUS) by combining the region and classification information. We use a random walk algorithm to express the region information efficiently and flexibly because it can avoid segmentation leakage and shrinking bias. We further use the decision tree as the classifier to distinguish the prostate from the non-prostate tissue because of its fast speed and superior performance, especially for a binary classification problem. Our segmentation algorithm is initialized with the user roughly marking the prostate and non-prostate points on the mid-gland slice which are fitted into an ellipse for obtaining more points. Based on these fitted seed points, we run the random walk algorithm to segment the prostate on the mid-gland slice. The segmented contour and the information from the decision tree classification are combined to determine the initial seed points for the other slices. The random walk algorithm is then used to segment the prostate on the adjacent slice. We propagate the process until all slices are segmented. The segmentation method was tested in 32 3D transrectal ultrasound images. Manual segmentation by a radiologist serves as the gold standard for the validation. The experimental results show that the proposed method achieved a Dice similarity coefficient of 91.37+/-0.05%. The segmentation method can be applied to 3D ultrasound-guided prostate biopsy and other applications.

  3. 3-D airborne ultrasound synthetic aperture imaging based on capacitive micromachined ultrasonic transducers.

    PubMed

    Park, Kwan Kyu; Khuri-Yakub, Butrus T

    2013-09-01

    In this paper, we present an airborne 3-D volumetric imaging system based on capacitive micromachined ultrasonic transducers (CMUTs). For this purpose we fabricated 89-kHz CMUTs where each CMUT is made of a circular single-crystal silicon plate with a radius of 1mm and a thickness of 20 μm, which is actuated by electrostatic force through a 20-μm vacuum gap. The measured transmit sensitivity at 300-V DC bias is 14.6 Pa/V and 24.2 Pa/V, when excited by a 30-cycle burst and a continuous wave, respectively. The measured receive sensitivity at 300-V DC bias is 16.6 mV/Pa (-35.6 dB re 1 V/Pa) for a 30-cycle burst. A 26×26 2-D array was implemented by mechanical scanning a co-located transmitter and receiver using the classic synthetic aperture (CSA) method. The measurement of a 1.6λ-size target at a distance of 500 mm presented a lateral resolution of 3.17° and also showed good agreement with the theoretical point spread function. The 3-D imaging of two plates at a distance of 350 mm and 400 mm was constructed to exhibit the capability of the imaging system. This study experimentally demonstrates that a 2-D CMUT array can be used for practical 3-D imaging applications in air, such as a human-machine interface.

  4. Intuitive terrain reconstruction using height observation-based ground segmentation and 3D object boundary estimation.

    PubMed

    Song, Wei; Cho, Kyungeun; Um, Kyhyun; Won, Chee Sun; Sim, Sungdae

    2012-12-12

    Mobile robot operators must make rapid decisions based on information about the robot's surrounding environment. This means that terrain modeling and photorealistic visualization are required for the remote operation of mobile robots. We have produced a voxel map and textured mesh from the 2D and 3D datasets collected by a robot's array of sensors, but some upper parts of objects are beyond the sensors' measurements and these parts are missing in the terrain reconstruction result. This result is an incomplete terrain model. To solve this problem, we present a new ground segmentation method to detect non-ground data in the reconstructed voxel map. Our method uses height histograms to estimate the ground height range, and a Gibbs-Markov random field model to refine the segmentation results. To reconstruct a complete terrain model of the 3D environment, we develop a 3D boundary estimation method for non-ground objects. We apply a boundary detection technique to the 2D image, before estimating and refining the actual height values of the non-ground vertices in the reconstructed textured mesh. Our proposed methods were tested in an outdoor environment in which trees and buildings were not completely sensed. Our results show that the time required for ground segmentation is faster than that for data sensing, which is necessary for a real-time approach. In addition, those parts of objects that were not sensed are accurately recovered to retrieve their real-world appearances.

  5. Model-based 3D human shape estimation from silhouettes for virtual fitting

    NASA Astrophysics Data System (ADS)

    Saito, Shunta; Kouchi, Makiko; Mochimaru, Masaaki; Aoki, Yoshimitsu

    2014-03-01

    We propose a model-based 3D human shape reconstruction system from two silhouettes. Firstly, we synthesize a deformable body model from 3D human shape database consists of a hundred whole body mesh models. Each mesh model is homologous, so that it has the same topology and same number of vertices among all models. We perform principal component analysis (PCA) on the database and synthesize an Active Shape Model (ASM). ASM allows changing the body type of the model with a few parameters. The pose changing of our model can be achieved by reconstructing the skeleton structures from implanted joints of the model. By applying pose changing after body type deformation, our model can represents various body types and any pose. We apply the model to the problem of 3D human shape reconstruction from front and side silhouette. Our approach is simply comparing the contours between the model's and input silhouettes', we then use only torso part contour of the model to reconstruct whole shape. We optimize the model parameters by minimizing the difference between corresponding silhouettes by using a stochastic, derivative-free non-linear optimization method, CMA-ES.

  6. 3D through silicon via profile metrology based on spectroscopic reflectometry for SOI applications

    NASA Astrophysics Data System (ADS)

    Fursenko, O.; Bauer, J.; Marschmeyer, S.

    2016-04-01

    Through-silicon via (TSV) technology is a key feature for 3D circuit integration. TSVs are formed by etching a vertical via and filling them with a conductive material for creation of interconnections which go through the silicon or silicon-on-insulator (SOI) wafer. The Bosch etch process on Deep Reactive Ion Etching (DRIE) is commonly used for this purpose. The etch profile defined by the critical dimensions (CDs) at the top and at the bottom, by the depth and by the scallop size on the sidewall needs to be monitored and well controlled. In this work a nondestructive 3D metrology of deeply-etched structures with an aspect ratio of more than 10 and patterns with lateral dimensions from 2 to 7 μm in SOI wafer is proposed. Spectroscopic reflectometry in the spectral range of 250-800 nm using a production metrology tool was applied. The depth determinations based on different algorithms are compared. The Pearson correlation coefficient between measured and calculated reflection is suggested as the most appropriate method. A simple method for top CD evaluation is proposed by the measurement of reflection and using the polynomial approximation of reflection versus TSV filling coefficient which is determined as ratio of CD to pitch. The 3D RCWA simulations confirm this dependence.

  7. An inverse hyper-spherical harmonics-based formulation for reconstructing 3D volumetric lung deformations

    NASA Astrophysics Data System (ADS)

    Santhanam, Anand P.; Min, Yugang; Mudur, Sudhir P.; Rastogi, Abhinav; Ruddy, Bari H.; Shah, Amish; Divo, Eduardo; Kassab, Alain; Rolland, Jannick P.; Kupelian, Patrick

    2010-07-01

    A method to estimate the deformation operator for the 3D volumetric lung dynamics of human subjects is described in this paper. For known values of air flow and volumetric displacement, the deformation operator and subsequently the elastic properties of the lung are estimated in terms of a Green's function. A Hyper-Spherical Harmonic (HSH) transformation is employed to compute the deformation operator. The hyper-spherical coordinate transformation method discussed in this paper facilitates accounting for the heterogeneity of the deformation operator using a finite number of frequency coefficients. Spirometry measurements are used to provide values for the airflow inside the lung. Using a 3D optical flow-based method, the 3D volumetric displacement of the left and right lungs, which represents the local anatomy and deformation of a human subject, was estimated from 4D-CT dataset. Results from an implementation of the method show the estimation of the deformation operator for the left and right lungs of a human subject with non-small cell lung cancer. Validation of the proposed method shows that we can estimate the Young's modulus of each voxel within a 2% error level.

  8. Random Walk Based Segmentation for the Prostate on 3D Transrectal Ultrasound Images

    PubMed Central

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Nieh, Peter T.; Master, Viraj V.; Schuster, David M.; Fei, Baowei

    2016-01-01

    This paper proposes a new semi-automatic segmentation method for the prostate on 3D transrectal ultrasound images (TRUS) by combining the region and classification information. We use a random walk algorithm to express the region information efficiently and flexibly because it can avoid segmentation leakage and shrinking bias. We further use the decision tree as the classifier to distinguish the prostate from the non-prostate tissue because of its fast speed and superior performance, especially for a binary classification problem. Our segmentation algorithm is initialized with the user roughly marking the prostate and non-prostate points on the mid-gland slice which are fitted into an ellipse for obtaining more points. Based on these fitted seed points, we run the random walk algorithm to segment the prostate on the mid-gland slice. The segmented contour and the information from the decision tree classification are combined to determine the initial seed points for the other slices. The random walk algorithm is then used to segment the prostate on the adjacent slice. We propagate the process until all slices are segmented. The segmentation method was tested in 32 3D transrectal ultrasound images. Manual segmentation by a radiologist serves as the gold standard for the validation. The experimental results show that the proposed method achieved a Dice similarity coefficient of 91.37±0.05%. The segmentation method can be applied to 3D ultrasound-guided prostate biopsy and other applications. PMID:27660383

  9. PACS-based interface for 3D anatomical structure visualization and surgical planning

    NASA Astrophysics Data System (ADS)

    Koehl, Christophe; Soler, Luc; Marescaux, Jacques

    2002-05-01

    The interpretation of radiological image is routine but it remains a rather difficult task for physicians. It requires complex mental processes, that permit translation from 2D slices into 3D localization and volume determination of visible diseases. An easier and more extensive visualization and exploitation of medical images can be reached through the use of computer-based systems that provide real help from patient admission to post-operative followup. In this way, we have developed a 3D visualization interface linked to a PACS database that allows manipulation and interaction on virtual organs delineated from CT-scan or MRI. This software provides the 3D real-time surface rendering of anatomical structures, an accurate evaluation of volumes and distances and the improvement of radiological image analysis and exam annotation through a negatoscope tool. It also provides a tool for surgical planning allowing the positioning of an interactive laparoscopic instrument and the organ resection. The software system could revolutionize the field of computerized imaging technology. Indeed, it provides a handy and portable tool for pre-operative and intra-operative analysis of anatomy and pathology in various medical fields. This constitutes the first step of the future development of augmented reality and surgical simulation systems.

  10. A Skeleton-Based 3D Shape Reconstruction of Free-Form Objects with Stereo Vision

    NASA Astrophysics Data System (ADS)

    Saini, Deepika; Kumar, Sanjeev

    2015-12-01

    In this paper, an efficient approach is proposed for recovering the 3D shape of a free-form object from its arbitrary pair of stereo images. In particular, the reconstruction problem is treated as the reconstruction of the skeleton and the external boundary of the object. The reconstructed skeleton is termed as the line-like representation or curve-skeleton of the 3D object. The proposed solution for object reconstruction is based on this evolved curve-skeleton. It is used as a seed for recovering shape of the 3D object, and the extracted boundary is used for terminating the growing process of the object. NURBS-skeleton is used to extract the skeleton of both views. Affine invariant property of the convex hulls is used to establish the correspondence between the skeletons and boundaries in the stereo images. In the growing process, a distance field is defined for each skeleton point as the smallest distance from that point to the boundary of the object. A sphere centered at a skeleton point of radius equal to the minimum distance to the boundary is tangential to the boundary. Filling in the spheres centered at each skeleton point reconstructs the object. Several results are presented in order to check the applicability and validity of the proposed algorithm.

  11. Intuitive Terrain Reconstruction Using Height Observation-Based Ground Segmentation and 3D Object Boundary Estimation

    PubMed Central

    Song, Wei; Cho, Kyungeun; Um, Kyhyun; Won, Chee Sun; Sim, Sungdae

    2012-01-01

    Mobile robot operators must make rapid decisions based on information about the robot’s surrounding environment. This means that terrain modeling and photorealistic visualization are required for the remote operation of mobile robots. We have produced a voxel map and textured mesh from the 2D and 3D datasets collected by a robot’s array of sensors, but some upper parts of objects are beyond the sensors’ measurements and these parts are missing in the terrain reconstruction result. This result is an incomplete terrain model. To solve this problem, we present a new ground segmentation method to detect non-ground data in the reconstructed voxel map. Our method uses height histograms to estimate the ground height range, and a Gibbs-Markov random field model to refine the segmentation results. To reconstruct a complete terrain model of the 3D environment, we develop a 3D boundary estimation method for non-ground objects. We apply a boundary detection technique to the 2D image, before estimating and refining the actual height values of the non-ground vertices in the reconstructed textured mesh. Our proposed methods were tested in an outdoor environment in which trees and buildings were not completely sensed. Our results show that the time required for ground segmentation is faster than that for data sensing, which is necessary for a real-time approach. In addition, those parts of objects that were not sensed are accurately recovered to retrieve their real-world appearances. PMID:23235454

  12. Automatic 3D liver segmentation based on deep learning and globally optimized surface evolution.

    PubMed

    Hu, Peijun; Wu, Fa; Peng, Jialin; Liang, Ping; Kong, Dexing

    2016-12-21

    The detection and delineation of the liver from abdominal 3D computed tomography (CT) images are fundamental tasks in computer-assisted liver surgery planning. However, automatic and accurate segmentation, especially liver detection, remains challenging due to complex backgrounds, ambiguous boundaries, heterogeneous appearances and highly varied shapes of the liver. To address these difficulties, we propose an automatic segmentation framework based on 3D convolutional neural network (CNN) and globally optimized surface evolution. First, a deep 3D CNN is trained to learn a subject-specific probability map of the liver, which gives the initial surface and acts as a shape prior in the following segmentation step. Then, both global and local appearance information from the prior segmentation are adaptively incorporated into a segmentation model, which is globally optimized in a surface evolution way. The proposed method has been validated on 42 CT images from the public Sliver07 database and local hospitals. On the Sliver07 online testing set, the proposed method can achieve an overall score of [Formula: see text], yielding a mean Dice similarity coefficient of [Formula: see text], and an average symmetric surface distance of [Formula: see text] mm. The quantitative validations and comparisons show that the proposed method is accurate and effective for clinical application.

  13. A variable flip angle-based method for reducing blurring in 3D GRASE ASL

    NASA Astrophysics Data System (ADS)

    Liang, Xiaoyun; Connelly, Alan; Tournier, Jacques-Donald; Calamante, Fernando

    2014-09-01

    Arterial Spin Labeling (ASL) is an MRI technique to measure cerebral blood flow directly and noninvasively, and thus provides a more direct quantitative correlate of neural activity than blood-oxygen-level-dependent fMRI. A 3D gradient and spin-echo (GRASE) sequence is capable of enhancing signal-to-noise ratio, and has been shown to be a very useful readout module for ASL sequences. Nonetheless, the introduction of significant blurring in its single-shot version, due to T2 decay along the partition dimension, compromises the achievable spatial resolution, limiting the potential of this technique for whole-brain coverage. To address this issue, a method for reducing blurring based on a variable flip angle (VFA) scheme is proposed in this study for 3D GRASE ASL perfusion. Numerical simulations show that the proposed method is capable of reducing the blurring significantly compared to the standard constant flip angle approach; this result was further confirmed using in vivo data. The proposed VFA method should therefore be of significance to 3D GRASE ASL fMRI studies, since it is able to reduce blurring without sacrificing temporal resolution.

  14. Automatic 3D liver segmentation based on deep learning and globally optimized surface evolution

    NASA Astrophysics Data System (ADS)

    Hu, Peijun; Wu, Fa; Peng, Jialin; Liang, Ping; Kong, Dexing

    2016-12-01

    The detection and delineation of the liver from abdominal 3D computed tomography (CT) images are fundamental tasks in computer-assisted liver surgery planning. However, automatic and accurate segmentation, especially liver detection, remains challenging due to complex backgrounds, ambiguous boundaries, heterogeneous appearances and highly varied shapes of the liver. To address these difficulties, we propose an automatic segmentation framework based on 3D convolutional neural network (CNN) and globally optimized surface evolution. First, a deep 3D CNN is trained to learn a subject-specific probability map of the liver, which gives the initial surface and acts as a shape prior in the following segmentation step. Then, both global and local appearance information from the prior segmentation are adaptively incorporated into a segmentation model, which is globally optimized in a surface evolution way. The proposed method has been validated on 42 CT images from the public Sliver07 database and local hospitals. On the Sliver07 online testing set, the proposed method can achieve an overall score of 80.3+/- 4.5 , yielding a mean Dice similarity coefficient of 97.25+/- 0.65 % , and an average symmetric surface distance of 0.84+/- 0.25 mm. The quantitative validations and comparisons show that the proposed method is accurate and effective for clinical application.

  15. Autostereoscopic 3D Display with Long Visualization Depth Using Referential Viewing Area-Based Integral Photography.

    PubMed

    Hongen Liao; Dohi, Takeyoshi; Nomura, Keisuke

    2011-11-01

    We developed an autostereoscopic display for distant viewing of 3D computer graphics (CG) images without using special viewing glasses or tracking devices. The images are created by employing referential viewing area-based CG image generation and pixel distribution algorithm for integral photography (IP) and integral videography (IV) imaging. CG image rendering is used to generate IP/IV elemental images. The images can be viewed from each viewpoint within a referential viewing area and the elemental images are reconstructed from rendered CG images by pixel redistribution and compensation method. The elemental images are projected onto a screen that is placed at the same referential viewing distance from the lens array as in the image rendering. Photographic film is used to record the elemental images through each lens. The method enables 3D images with a long visualization depth to be viewed from relatively long distances without any apparent influence from deviated or distorted lenses in the array. We succeeded in creating an actual autostereoscopic images with an image depth of several meters in front of and behind the display that appear to have 3D even when viewed from a distance.

  16. Statistical and neural network classifiers in model-based 3-D object recognition

    NASA Astrophysics Data System (ADS)

    Newton, Scott C.; Nutter, Brian S.; Mitra, Sunanda

    1991-02-01

    For autonomous machines equipped with vision capabilities and in a controlled environment 3-D model-based object identification methodologies will in general solve rigid body recognition problems. In an uncontrolled environment however several factors pose difficulties for correct identification. We have addressed the problem of 3-D object recognition using a number of methods including neural network classifiers and a Bayesian-like classifier for matching image data with model projection-derived data [1 21. Neural network classifiers used began operation as simple feature vector classifiers. However unmodelled signal behavior was learned with additional samples yielding great improvement in classification rates. The model analysis drastically shortened training time of both classification systems. In an environment where signal behavior is not accurately modelled two separate forms of learning give the systems the ability to update estimates of this behavior. Required of course are sufficient samples to learn this new information. Given sufficient information and a well-controlled environment identification of 3-D objects from a limited number of classes is indeed possible. 1.

  17. Scientific rotoscoping: a morphology-based method of 3-D motion analysis and visualization.

    PubMed

    Gatesy, Stephen M; Baier, David B; Jenkins, Farish A; Dial, Kenneth P

    2010-06-01

    Three-dimensional skeletal movement is often impossible to accurately quantify from external markers. X-ray imaging more directly visualizes moving bones, but extracting 3-D kinematic data is notoriously difficult from a single perspective. Stereophotogrammetry is extremely powerful if bi-planar fluoroscopy is available, yet implantation of three radio-opaque markers in each segment of interest may be impractical. Herein we introduce scientific rotoscoping (SR), a new method of motion analysis that uses articulated bone models to simultaneously animate and quantify moving skeletons without markers. The three-step process is described using examples from our work on pigeon flight and alligator walking. First, the experimental scene is reconstructed in 3-D using commercial animation software so that frames of undistorted fluoroscopic and standard video can be viewed in their correct spatial context through calibrated virtual cameras. Second, polygonal models of relevant bones are created from CT or laser scans and rearticulated into a hierarchical marionette controlled by virtual joints. Third, the marionette is registered to video images by adjusting each of its degrees of freedom over a sequence of frames. SR outputs high-resolution 3-D kinematic data for multiple, unmarked bones and anatomically accurate animations that can be rendered from any perspective. Rather than generating moving stick figures abstracted from the coordinates of independent surface points, SR is a morphology-based method of motion analysis deeply rooted in osteological and arthrological data.

  18. Meanie3D - a mean-shift based, multivariate, multi-scale clustering and tracking algorithm

    NASA Astrophysics Data System (ADS)

    Simon, Jürgen-Lorenz; Malte, Diederich; Silke, Troemel

    2014-05-01

    Project OASE is the one of 5 work groups at the HErZ (Hans Ertel Centre for Weather Research), an ongoing effort by the German weather service (DWD) to further research at Universities concerning weather prediction. The goal of project OASE is to gain an object-based perspective on convective events by identifying them early in the onset of convective initiation and follow then through the entire lifecycle. The ability to follow objects in this fashion requires new ways of object definition and tracking, which incorporate all the available data sets of interest, such as Satellite imagery, weather Radar or lightning counts. The Meanie3D algorithm provides the necessary tool for this purpose. Core features of this new approach to clustering (object identification) and tracking are the ability to identify objects using the mean-shift algorithm applied to a multitude of variables (multivariate), as well as the ability to detect objects on various scales (multi-scale) using elements of Scale-Space theory. The algorithm works in 2D as well as 3D without modifications. It is an extension of a method well known from the field of computer vision and image processing, which has been tailored to serve the needs of the meteorological community. In spite of the special application to be demonstrated here (like convective initiation), the algorithm is easily tailored to provide clustering and tracking for a wide class of data sets and problems. In this talk, the demonstration is carried out on two of the OASE group's own composite sets. One is a 2D nationwide composite of Germany including C-Band Radar (2D) and Satellite information, the other a 3D local composite of the Bonn/Jülich area containing a high-resolution 3D X-Band Radar composite.

  19. Microchip-Based Electrochemical Detection using a 3-D Printed Wall-Jet Electrode Device

    PubMed Central

    Munshi, Akash S.; Martin, R. Scott

    2016-01-01

    Three dimensional (3-D) printing technology has evolved dramatically in the last few years, offering the capability of printing objects with a variety of materials. Printing microfluidic devices using this technology offers various advantages such as ease and uniformity of fabrication, file sharing between laboratories, and increased device-to-device reproducibility. One unique aspects of this technology, when used with electrochemical detection, is the ability to produce a microfluidic device as one unit while also allowing the reuse of the device and electrode for multiple analyses. Here we present an alternate electrode configuration for microfluidic devices, a wall-jet electrode (WJE) approach, created by 3-D printing. Using microchip-based flow injection analysis, we compared the WJE design with the conventionally used thin-layer electrode (TLE) design. It was found that the optimized WJE system enhances analytical performance (as compared to the TLE design), with improvements in sensitivity and the limit of detection. Experiments were conducted using two working electrodes – 500 μm platinum and 1 mm glassy carbon. Using the 500 μm platinum electrode the calibration sensitivity was 16 times higher for the WJE device (as compared to the TLE design). In addition, use of the 1 mm glassy carbon electrode led to limit of detection of 500 nM for catechol, as compared to 6 μM for the TLE device. Finally, to demonstrate the versatility and applicability of the 3-D printed WJE approach, the device was used as an inexpensive electrochemical detector for HPLC. The number of theoretical plates was comparable to the use of commercially available UV and MS detectors, with the WJE device being inexpensive to utilize. These results show that 3D-printing can be a powerful tool to fabricate reusable and integrated microfluidic detectors in configurations that are not easily achieved with more traditional lithographic methods. PMID:26649363

  20. Advantages and drawbacks of Thiol-ene based resins for 3D-printing

    NASA Astrophysics Data System (ADS)

    Leonards, Holger; Engelhardt, Sascha; Hoffmann, Andreas; Pongratz, Ludwig; Schriever, Sascha; Bläsius, Jana; Wehner, Martin; Gillner, Arnold

    2015-03-01

    The technology of 3D printing is conquering the world and awakens the interest of many users in the most varying of applications. New formulation approaches for photo-sensitive thiol-ene resins in combination with various printing technologies, like stereolithography (SLA), projection based printing/digital light processing (DLP) or two-photon polymerization (TPP) are presented. Thiol-ene polymerizations are known for its fast and quantitative reaction and to form highly homogeneous polymer networks. As the resins are locally and temporally photo-curable the polymerization type is very promising for 3D-printing. By using suitable wavelengths, photoinitiator-free fabrication is feasible for single- and two photon induced polymerization. In this paper divinyl ethers of polyethylene glycols in combination with star-shaped tetrathiols were used to design a simple test-system for photo-curable thiol-ene resins. In order to control and improve curing depth and lateral resolution in 3D-polymerization processes, either additives in chemical formulation or process parameters can be changed. The achieved curing depth and resolution limits depend on the applied fabrication method. While two-/multiphoton induced lithography offers the possibility of micron- to sub-micron resolution it lacks in built-up speed. Hence single-photon polymerization is a fast alternative with optimization potential in sub-10-micron resolution. Absorber- and initiator free compositions were developed in order to avoid aging, yellowing and toxicity of resulting products. They can be cured with UV-laser radiation below 300 nm. The development at Fraunhofer ILT is focusing on new applications in the field of medical products and implants, technical products with respect to mechanical properties or optical properties of 3D-printed objects. Recent process results with model system (polyethylene glycol divinylether/ Pentaerithrytol tetrakis (3-mercaptopropionat), Raman measurements of polymer conversion

  1. A 3-D cardiac muscle construct for exploring adult marrow stem cell based myocardial regeneration.

    PubMed

    Valarmathi, Mani T; Goodwin, Richard L; Fuseler, John W; Davis, Jeffrey M; Yost, Michael J; Potts, Jay D

    2010-04-01

    Adult bone marrow stromal cells (BMSCs) are capable of differentiating into cardiomyocyte-like cells in vitro and contribute to myocardial regeneration in vivo. Consequently, BMSCs may potentially play a vital role in cardiac repair and regeneration. However, this concept has been limited by inadequate and inconsistent differentiation of BMSCs into cardiomyocytes along with poor survival and integration of neo-cardiomyocytes after implantation into ischemic myocardium. In order to overcome these barriers and to explore adult stem cell based myocardial regeneration, we have developed an in vitro model of three-dimensional (3-D) cardiac muscle using rat ventricular embryonic cardiomyocytes (ECMs) and BMSCs. When ECMs and BMSCs were seeded sequentially onto a 3-D tubular scaffold engineered from topographically aligned type I collagen-fibers and cultured in basal medium for 7, 14, 21, or 28 days, the maturation and co-differentiation into a cardiomyocyte lineage was observed. Phenotypic induction was characterized at morphological, immunological, biochemical and molecular levels. The observed expression of transcripts coding for cardiomyocyte phenotypic markers and the immunolocalization of cardiomyogenic lineage-associated proteins revealed typical expression patterns of neo-cardiomyogenesis. At the biochemical level differentiating cells exhibited appropriate metabolic activity and at the ultrastructural level myofibrillar and sarcomeric organization were indicative of an immature phenotype. Our 3-D co-culture system sustains the ECMs in vitro continuum of differentiation process and simultaneously induces the maturation and differentiation of BMSCs into cardiomyocyte-like cells. Thus, this novel 3-D co-culture system provides a useful in vitro model to investigate the functional role and interplay of developing ECMs and BMSCs during cardiomyogenic differentiation.

  2. Microchip-based electrochemical detection using a 3-D printed wall-jet electrode device.

    PubMed

    Munshi, Akash S; Martin, R Scott

    2016-02-07

    Three dimensional (3-D) printing technology has evolved dramatically in the last few years, offering the capability of printing objects with a variety of materials. Printing microfluidic devices using this technology offers various advantages such as ease and uniformity of fabrication, file sharing between laboratories, and increased device-to-device reproducibility. One unique aspect of this technology, when used with electrochemical detection, is the ability to produce a microfluidic device as one unit while also allowing the reuse of the device and electrode for multiple analyses. Here we present an alternate electrode configuration for microfluidic devices, a wall-jet electrode (WJE) approach, created by 3-D printing. Using microchip-based flow injection analysis, we compared the WJE design with the conventionally used thin-layer electrode (TLE) design. It was found that the optimized WJE system enhances analytical performance (as compared to the TLE design), with improvements in sensitivity and the limit of detection. Experiments were conducted using two working electrodes - 500 μm platinum and 1 mm glassy carbon. Using the 500 μm platinum electrode the calibration sensitivity was 16 times higher for the WJE device (as compared to the TLE design). In addition, use of the 1 mm glassy carbon electrode led to limit of detection of 500 nM for catechol, as compared to 6 μM for the TLE device. Finally, to demonstrate the versatility and applicability of the 3-D printed WJE approach, the device was used as an inexpensive electrochemical detector for HPLC. The number of theoretical plates was comparable to the use of commercially available UV and MS detectors, with the WJE device being inexpensive to utilize. These results show that 3-D-printing can be a powerful tool to fabricate reusable and integrated microfluidic detectors in configurations that are not easily achieved with more traditional lithographic methods.

  3. Artificial neural networks and model-based recognition of 3-D objects from 2-D images

    NASA Astrophysics Data System (ADS)

    Chao, Chih-Ho; Dhawan, Atam P.

    1992-09-01

    A computer vision system is developed for 3-D object recognition using artificial neural networks and a knowledge-based top-down feedback analysis system. This computer vision system can adequately analyze an incomplete edge map provided by a low-level processor for 3-D representation and recognition using key features. The key features are selected using a priority assignment and then used in an artificial neural network for matching with model key features. The result of such matching is utilized in generating the model-driven top-down feedback analysis. From the incomplete edge map we try to pick a candidate pattern utilizing the key feature priority assignment. The highest priority is given for the most connected node and associated features. The features are space invariant structures and sets of orientation for edge primitives. These features are now mapped into real numbers. A Hopfield network is then applied with two levels of matching to reduce the search time. The first match is to choose the class of possible model, the second match is then to find the model closest to the data patterns. This model is then rotated in 3-D to find the best match with the incomplete edge patterns and to provide the additional features in 3-D. In the case of multiple objects, a dynamically interconnected search strategy is designed to recognize objects using one pattern at a time. This strategy is also useful in recognizing occluded objects. The experimental results presented show the capability and effectiveness of this system.

  4. Full 3-D OCT-based pseudophakic custom computer eye model

    PubMed Central

    Sun, M.; Pérez-Merino, P.; Martinez-Enriquez, E.; Velasco-Ocana, M.; Marcos, S.

    2016-01-01

    We compared measured wave aberrations in pseudophakic eyes implanted with aspheric intraocular lenses (IOLs) with simulated aberrations from numerical ray tracing on customized computer eye models, built using quantitative 3-D OCT-based patient-specific ocular geometry. Experimental and simulated aberrations show high correlation (R = 0.93; p<0.0001) and similarity (RMS for high order aberrations discrepancies within 23.58%). This study shows that full OCT-based pseudophakic custom computer eye models allow understanding the relative contribution of optical geometrical and surgically-related factors to image quality, and are an excellent tool for characterizing and improving cataract surgery. PMID:27231608

  5. Implemented Wavelet Packet Tree based Denoising Algorithm in Bus Signals of a Wearable Sensorarray

    NASA Astrophysics Data System (ADS)

    Schimmack, M.; Nguyen, S.; Mercorelli, P.

    2015-11-01

    This paper introduces a thermosensing embedded system with a sensor bus that uses wavelets for the purposes of noise location and denoising. From the principle of the filter bank the measured signal is separated in two bands, low and high frequency. The proposed algorithm identifies the defined noise in these two bands. With the Wavelet Packet Transform as a method of Discrete Wavelet Transform, it is able to decompose and reconstruct bus input signals of a sensor network. Using a seminorm, the noise of a sequence can be detected and located, so that the wavelet basis can be rearranged. This particularly allows for elimination of any incoherent parts that make up unavoidable measuring noise of bus signals. The proposed method was built based on wavelet algorithms from the WaveLab 850 library of the Stanford University (USA). This work gives an insight to the workings of Wavelet Transformation.

  6. Denoising method of heart sound signals based on self-construct heart sound wavelet

    NASA Astrophysics Data System (ADS)

    Cheng, Xiefeng; Zhang, Zheng

    2014-08-01

    In the field of heart sound signal denoising, the wavelet transform has become one of the most effective measures. The selective wavelet basis is based on the well-known orthogonal db series or biorthogonal bior series wavelet. In this paper we present a self-construct wavelet basis which is suitable for the heart sound denoising and analyze its constructor method and features in detail according to the characteristics of heart sound and evaluation criterion of signal denoising. The experimental results show that the heart sound wavelet can effectively filter out the noise of the heart sound signals, reserve the main characteristics of the signal. Compared with the traditional wavelets, it has a higher signal-to-noise ratio, lower mean square error and better denoising effect.

  7. 3D delivered dose assessment using a 4DCT-based motion model

    SciTech Connect

    Cai, Weixing; Hurwitz, Martina H.; Williams, Christopher L.; Dhou, Salam; Berbeco, Ross I.; Mishra, Pankaj E-mail: jhlewis@lroc.harvard.edu; Lewis, John H. E-mail: jhlewis@lroc.harvard.edu; Seco, Joao

    2015-06-15

    Purpose: The purpose of this work is to develop a clinically feasible method of calculating actual delivered dose distributions for patients who have significant respiratory motion during the course of stereotactic body radiation therapy (SBRT). Methods: A novel approach was proposed to calculate the actual delivered dose distribution for SBRT lung treatment. This approach can be specified in three steps. (1) At the treatment planning stage, a