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Making 3d objects through bimanual actions

Making 3D objects through bimanual actions

IEEE International Conference on Systems, Man, and Cybernetics - Intelligent Systems for Humans in a Cyberworld (SMC 98)

作者： Nishino, H Nariman, d Utsumiya, K Korida, K Oita Univ Dept Comp Sci & Intelligent Syst Oita 8701192 Japan

ISBN: (纸本)0780347781

While many sophisticated 3d rendering methods become available to produce realistic output, 3d data input still is a tedious and time-consuming task. This paper proposes a new method for creating 3d objects using hand gestures. Two types of 3d shape forming tasks are considered. One is to create a completely new object from scratch and the other is to make it by changing an existing one. In the first case, a 3d modeling method is designed and implemented to provide functions like creation, blending and deformation of multiple 3d shapes easily controlled by intuitive bimanual gestures. The implicit superquadric functions apply to build a gesture-based 3d object modeler with extensions of blending and deformations. In the second case, a 3d data management function is proposed to share and reuse existing shapes created by using the 3d modeler mentioned above. All 3d data are kept small in size and retrieved by picturing partial shapes with user's both hands. As a consequence, the proposed method allows users to consistently deal with all object modeling tasks including creation, storage and reuse of 3d objects through natural and intuitive hand gestures. Some 3d objects and a miniature solid model are shown to present the expressive power and usefulness of the proposed method.

关键词： hand gesture interface 3d object modeling superquadrics virtual environment computer graphics

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Finite-resolution aspect graphs of polyhedral objects

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IEEE TRANSACTIONS ON PATTERN ANALYSIS ANd MACHINE INTELLIGENCE 1997年第4期19卷 315-327页

作者： Shimshoni, I Ponce, J UNIV ILLINOIS DEPT COMP SCIURBANAIL 61801 UNIV ILLINOIS BECKMAN INSTURBANAIL 61801

We address the problem of computing the aspect graph of a polyhedral object observed by an orthographic camera with limited spatial resolution, such that two image points separated by a distance smaller than a preset threshold cannot be resolved. Under this model, views that would differ under normal orthographic projection may become equivalent, while ''accidental'' views may occur over finite areas of the view space. We present a catalogue of visual events for polyhedral objects and give an algorithm for computing the aspect graph and enumerating all qualitatively different aspects. The algorithm has been fully implemented and results are presented.

关键词： computer vision 3d object modeling aspect graphs image resolution

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An integral approach to free-form object modeling

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IEEE TRANSACTIONS ON PATTERN ANALYSIS ANd MACHINE INTELLIGENCE 1997年第12期19卷 1366-1370页

作者： Shum, HY Hebert, M Ikeuchi, K Reddy, R CARNEGIE MELLON UNIV INST ROBOT PITTSBURGH PA 15213 USA UNIV TOKYO INST IND SCI MINATO KU TOKYO 106 JAPAN CARNEGIE MELLON UNIV SCH COMP SCI PITTSBURGH PA 15213 USA

This paper presents a new approach to free-form object modeling from multiple range images. In most conventional approaches, successive views are registered sequentially. In contrast to the sequential approaches, we propose an integral approach which reconstructs statistically optimal object models by simultaneously aggregating all data from multiple views into a weighted least-squares (WLS) formulation. The integral approach has two components. First, a global resampling algorithm constructs partial representations of the object from individual views, so that correspondence can be established among different views. Second, a weighted least-squares algorithm integrates resampled partial representations of multiple views, using the techniques of principal component analysis with missing data (PCAMd). Experiments show that our approach is robust against noise and mismatch.

关键词： 3d object modeling free-form object modeling multiple view merging principal component analysis resampling local curvature

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3d-3d registration of free formed objects using shape and texture

3D-3D registration of free formed objects using shape and te...

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1997 Conference on Visual Communications and Image Processing

作者： Martins, FCM Shiojiri, H Moura, JMF Carnegie Mellon Univ. (United States) NEC Corp. (Japan)

ISBN: (纸本)0819424358

Automatic generation of textured object models from a sequence of range and color images requires two major tasks: measurement registration and measurement integration. Measurement registration is the estimation of the current position and orientation of the object in 3d space with respect to an arbitrary fixed reference, given the current measurement and the 3d object model under construction. Measurement integration is the updating of the 3d object model using the current registered measurement. In this paper we present an iterative 3d-3d registration technique that uses both texture(1) and shape information available in the 3d object models and the 3d measurements. The proposed technique handles probabilistic models that are potentially incomplete before the measurement integration step. Measurements are acquired via a sensor characterized by a probabilistic sensor model. The object models are constructed automatically without user interaction. Each model is a compact uniform tessellation of 3d space, where each cell of the tessellation represents shape and texture in a probabilistic fashion. Free formed objects are supported and no prior knowledge about the object shape, texture or pose is assumed. Traditional registration methods consider only shape and geometric information. We consider texture information as an additional evidence by defining a generalized intercell distance measure that considers both the relative positioning of cells in space and the texture discrepancy between cells. Experimental results demonstrate the efficiency and robustness of the proposed method. The usefulness of texture in registration is highlighted in a comparison with results obtained considering only geometric information.

关键词： 3d-3d registration 3d pose estimation 3d object modeling textured geometric models range and image sequence processing

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Fractal geometry for atmospheric correction and canopy simulation 2

Fractal geometry for atmospheric correction and canopy simul...

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Conference on Algorithms for Multispectral and Hyperspectral Imagery II

作者： Tornow, C DLR GERMAN AEROSP RES ESTABINST SPACE SENSOR TECHNOLD-12484 BERLINGERMANY

ISBN: (纸本)0819421391

Global climate modeling needs a good parameterization of the vegetative surface. Two of the main important parameters are the leaf area index (LAI) and the fraction of absorbed photosynthetically active radiation (FPAR). In order to derive these values from space and airborne spectral radiance measurements one needs information on the actual atmospheric state as well as good canopy models. First we have developed a retrieval method for the optical depth to perform an atmospheric correction of remote sensing data. The atmospheric influence reduces the global image contrast and acts as a low pass filter. We found that the autocorrelation function [ACF_(lambda )(h)] of the image depends on the global image contrast C and on the fractal dimension s. Using multiple regression the spectral optical depth in the visible range can be estimated from C and s with an absolute accuracy of 0.021. This method was applied and tested for a number of rural TM scenes. Atmospheric correction allows us to calculate the canopy reflectance from the image data. The relationships between the canopy reflectance and LAI or FPAR can be determined from canopy radiative transfer modeling. Row and shadowing effects influence the bi-directional reflectance distribution function (BRdF) since the leaves and stems are real 3d objects. In order to use a ray tracer for 3d radiative transfer simulation the canopy should be described by simple shapes (discs, cylinders) and polygones. Lindenmayer systems which are based on the ideas of fractal geometry allow the construction of plants and trees in this way. We have created simple artificial plants and arranged them into rows to study shadowing and row effects and compute the BRdF in various spectral channels.

关键词： spectral optical depth fractals 3d object modeling BRdF

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PRINCIPAL COMPONENT ANALYSIS WITH MISSING dATA ANd ITS APPLICATION TO POLYHEdRAL object modeling

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IEEE TRANSACTIONS ON PATTERN ANALYSIS ANd MACHINE INTELLIGENCE 1995年第9期17卷 854-867页

作者： SHUM, HY IKEUCHI, K REddY, R Robotics Institute Carnegie Mellon University Pittsburgh PA USA

Observation-based object modeling often requires integration of shape descriptions from different views. In current conventional methods, to sequentially merge multiple views, an accurate description of each surface patch has to be precisely known in each view, and the transformation between adjacent views needs to be accurately recovered. When noisy data and mismatches are present, the recovered transformation become erroneous. In addition, the transformation errors accumulate and propagate along the sequence, resulting in an inaccurate object model. To overcome these problems, we have developed a weighted least-squares (WLS) approach which simultaneously recovers object shape and transformation among different views without recovering interframe motion as an intermediate step. We show that object modeling from a sequence of range images is a problem of principal component analysis with missing data (PCAMd), which can be generalized as a WLS minimization problem. An efficient algorithm is devised to solve the problem of PCAMd, After we have segmented planar surface regions in each view and tracked them over the image sequence, we construct a normal measurement matrix of surface normals, and a distance measurement matrix of normal distances to the origin for all visible regions appeared over the whole sequence of views, respectively. These two measurement matrices, which have many missing elements due to noise, occlusion, and mismatching, enable us to formulate multiple view merging as a combination of two WLS problems. A two-step algorithm is presented to computer planar surface descriptions and transformations among different views simultaneously, After surface equations are extracted, spatial connectivity among these surfaces is established to enable the polyhedral object model to be constructed. Experiments using synthetic data and real range images show that our approach is robust against noise and mismatching and generates accurate polyhedral object models by

关键词： COMPUTER VISION 3d object modeling MULTIPLE VIEW MERGING RANGE IMAGE PROCESSING PRINCIPAL COMPONENT ANALYSIS

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USING GEOMETRIC dISTANCE FITS FOR 3-d object modeling ANd RECOGNITION

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IEEE TRANSACTIONS ON PATTERN ANALYSIS ANd MACHINE INTELLIGENCE 1994年第12期16卷 1183-1196页

作者： SULLIVAN, S SANdFORd, L PONCE, J UNIV ILLINOIS DEPT COMP SCIURBANAIL 61801

This paper addresses the problems of automatically constructing algebraic surface models from sets of 2-d and 3-d images and using these models in pose computation, motion and deformation estimation, and object recognition. We propose using a combination of constrained optimization and nonlinear least-squares estimation techniques to minimize the mean-squared geometric distance between a set of points or rays and a parameterized surface. In modeling tasks, the unknown parameters are the surface coefficients, while in pose and deformation estimation tasks they represent the transformation mapping the observer's coordinate system onto the modeled surface's own coordinate system. We have applied this approach to a variety of real range, CT, and video images.

关键词： Solid modeling deformable models Surface fitting Motion estimation object recognition Constraint optimization Euclidean distance Image recognition Computational modeling Computed tomography INSPEC: Controlled Indexing deformation object recognition solid modelling algebra INSPEC: Non-Controlled Indexing implicit algebraic surfaces geometric distance fits 3d object modeling 3d object modeling and recognition algebraic surface models automatic model construction pose computation motion estimation deformation estimation constrained optimization nonlinear least-squares estimation techniques mean-squared geometric distance minimization point set ray set parameterized surface unknown parameters surface coefficients transformation mapping coordinate system range images computerized tomography images video images

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