# Proceedings of 1994 IEEE Workshop on Motion of Non-rigid and Articulated Objects

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• ### Proceedings of 1994 IEEE Workshop on Motion of Non-rigid and Articulated Objects

Publication Year: 1994
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• ### Contour tracking by multi-frame relaxation

Publication Year: 1994, Page(s):188 - 193
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This paper describes a novel feature tracking method. It is based on an inter-frame relaxation technique. This method combines intra-frame and inter-frame constraints on the behaviour of acceptable contour structure. The intra-frame information is represented by both a dictionary of local contour structure and a statistical model of the response of a set of directional feature detection operators.... View full abstract»

• ### An efficient method for contour tracking using active shape models

Publication Year: 1994, Page(s):194 - 199
Cited by:  Papers (69)  |  Patents (4)
| | PDF (380 KB)

There has been considerable research interest recently, in the areas of real time contour tracking and active shape models. This paper demonstrates how dynamic filtering can be used in combination with a modal-based flexible shape model to track an articulated non-rigid body in motion. The results show the method being used to track the silhouette of a walking pedestrian in real time. The active s... View full abstract»

• ### Robust algorithm for motion analysis based on Active Tubes

Publication Year: 1994, Page(s):200 - 205
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Determining motion of objects is a very important and difficult problem. Many researches have been studied in this field. We previously presented a new model, named Active Tubes, to find motion of non-rigid objects from an image sequence. Active Tubes analyzes the temporal context in a spatio-temporal solid using an energy minimizing model like Snakes. You can consider it as a kind of accumulation... View full abstract»

• ### Iterative estimation of non-rigid motion based on relative elasticity

Publication Year: 1994, Page(s):206 - 211
Cited by:  Papers (1)
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The vast majority of published research in motion has assumed that the imaged world moves in a rigid manner, even though this is an ill-posed assumption for recovering the motion parameters of many naturally occurring objects, such as clouds, plants, and animals. Unfortunately, if the rigidity of motion assumption is relaxed to allow deformation of motion, the problem of estimating the motion beco... View full abstract»

• ### Physically-based combinations of views: representing rigid and nonrigid motion

Publication Year: 1994, Page(s):158 - 164
Cited by:  Papers (11)
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Nonrigid motion can be described as morphing or blending between extremal shapes, e.g. heart motion can be described as transitioning between the systole and diastole states. Using physically-based modeling techniques, shape similarity can be measured in terms of forces and strain. This provides a physically-based coordinate system in which motion is characterized in terms of physical similarity t... View full abstract»

• ### Three dimensional transparent structure segmentation and multiple 3D motion estimation from monocular perspective image sequences

Publication Year: 1994, Page(s):228 - 235
Cited by:  Papers (9)  |  Patents (1)
| | PDF (620 KB)

A three dimensional scene can be segmented using different cues, such as boundaries, texture, motion, discontinuities of the optical flow, stereo, models for structure, etc. We investigate segmentation based upon one of these cues, namely three dimensional motion. If the scene contain transparent objects, the two dimensional (local) cues are inconsistent, since neighboring points with similar opti... View full abstract»

• ### Recognition and localization of articulated objects

Publication Year: 1994, Page(s):116 - 123
Cited by:  Papers (5)
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Presents a method for the localization and interpretation of modeled objects that is general enough to cover articulated and other types of constrained models. The flexibility between components of the model are expressed as spatial constraints which are fused into the pose estimation during the interpretation process. The constraint fusion assists in obtaining a precise and stable pose of each ob... View full abstract»

• ### Feature grouping in moving objects

Publication Year: 1994, Page(s):214 - 219
Cited by:  Papers (10)
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We address the problem of grouping points or features common to a single object. In this paper we consider the processing of a sequence of two-dimensional orthogonal projections of a three-dimensional scene containing an unknown number of independently-moving rigid objects. We describe a computationally inexpensive algorithm that can determine the number of bodies and which points belong to which ... View full abstract»

• ### Towards structure and motion estimation from dynamic silhouettes

Publication Year: 1994, Page(s):166 - 171
Cited by:  Papers (4)
| | PDF (500 KB)

Addresses the problem of estimating the structure and motion of a smooth curved object from its silhouettes observed over time by a trinocular imagery. We first construct a model for the local structure along the silhouette for each frame in the temporal sequence. The local models are then integrated into a global surface description by estimating the motion between successive frames. The algorith... View full abstract»

• ### Active motion-based segmentation of human body outlines

Publication Year: 1994, Page(s):50 - 56
Cited by:  Papers (1)
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We present an integrated approach towards the segmentation and shape estimation of human body outlines. Initially, we assume that the human body consists of a single part, and we fit a deformable model to the given data using our physics-based shape and motion estimation framework. As an actor attains different postures, new protrusions emerge on the outline. We model these changes in the shape us... View full abstract»

• ### Determining articulated motion from perspective views: a decomposition approach

Publication Year: 1994, Page(s):126 - 137
Cited by:  Papers (11)
| | PDF (840 KB)

The problem is to estimate the 3D motion of an articulated object, such as a robot arm or a human body, from a monocular sequence of 2D perspective views. We advocate an approach of decomposition. The object is decomposed into simpler parts, each containing a small number of links. We estimate the motion of the simplest part(s) and then propagate the analysis to the remaining parts of the object. ... View full abstract»

• ### Recognition of dexterous manipulations from time-varying images

Publication Year: 1994, Page(s):23 - 28
Cited by:  Papers (12)
| | PDF (504 KB)

This paper presents a method for recognizing dexterous manipulation actions that we usually perform using our hands. Our method is based on model representation using spatio-temporal vector fields and a spotting algorithm that gives segmentation-free and frame-by-frame recognition. We propose a multiview motion model that is composed of several standard sequence patterns made from different viewpo... View full abstract»

• ### A system for human motion matching between synthetic and real images based on a biomechanic graphical model

Publication Year: 1994, Page(s):83 - 88
Cited by:  Papers (10)
| | PDF (560 KB)

A system for analysis and synthesis of human motion is presented. The system consists of an analysis part and a synthesis part. The analysis part can be used automatically or interactively. The automatic analysis part includes the pre-processing, modeling, matching and interpretation phases. The interactive analysis part includes the same phases but with the possibility of user supervision. We pre... View full abstract»

• ### Lower limb kinematics of human walking with the medial axis transformation

Publication Year: 1994, Page(s):70 - 76
Cited by:  Papers (19)
| | PDF (512 KB)

The paper describes a simple model for free-speed human walking and compares ordinary images of a walking person to the model. Three dimensional kinematic data were obtained from subjects walking with markers over the joints of their limbs. The average of these data was used to derive a model stick figure of the lower limbs, based on the average anthropometric data of the population. Stick figures... View full abstract»

• ### Detecting irregularities in cyclic motion

Publication Year: 1994, Page(s):178 - 185
Cited by:  Papers (12)
| | PDF (580 KB)

Real cyclic motions tend not to be perfectly even, i.e., the period varies slightly from one cycle to the next, because of physically important changes in the scene. A generalization of period is defined for cyclic motions that makes periodic variation explicit. This representation, called the period trace, is compact and purely temporal, describing the evolution of an object or scene without refe... View full abstract»

• ### Adaptive and deformable models based on simplex meshes

Publication Year: 1994, Page(s):152 - 157
Cited by:  Papers (10)  |  Patents (2)
| | PDF (508 KB)

Simplex meshes are simply-connected meshes that are topologically the dual of triangulations. We have introduced a simplex mesh representation for recognizing partially-occluded smooth objects. In this paper, we present a physically-based approach for recovering 3D objects, based on the geometry of simplex meshes. Elastic behavior is modelled by local stabilizing functionals controlling the mean c... View full abstract»

• ### Estimating multiple independent motions in segmented images using parametric models with local deformations

Publication Year: 1994, Page(s):220 - 227
Cited by:  Papers (8)  |  Patents (2)
| | PDF (816 KB)

This paper presents a new model for optical flow based on the motion of planar regions plus local deformations. The approach exploits brightness information to organize and constrain the interpretation of the motion by using segmented regions of piecewise smooth brightness to hypothesize planar regions in the scene. Parametric flow models are fitted to these regions an a two step process which fir... View full abstract»

• ### A general approach for determining 3D motion and structure of multiple objects from image trajectories

Publication Year: 1994, Page(s):110 - 115
Cited by:  Patents (4)
| | PDF (408 KB)

Presents a general approach to determine the 3D motion and structure of multiple objects undergoing arbitrary motions. We segment the scene based on 3D motion parameters. First, the general motion model is fitted to each single trajectory. For this nonlinear fitting, initial estimates are obtained by a linear multiple-motion SFM (structure from motion) algorithm using the first two frames. Next, t... View full abstract»

• ### Human emotion recognition from motion using a radial basis function network architecture

Publication Year: 1994, Page(s):43 - 49
Cited by:  Papers (25)  |  Patents (2)
| | PDF (608 KB)

A radial basis function network architecture is developed that learns the correlation of facial feature motion patterns and human emotions. We describe a hierarchical approach which at the highest level identifies emotions, at the mid level determines motion of facial features, and at the low level recovers motion directions. Individual emotion networks were trained to recognize the smile' and s... View full abstract»

• ### DigitEyes: vision-based hand tracking for human-computer interaction

Publication Year: 1994, Page(s):16 - 22
Cited by:  Papers (70)  |  Patents (9)
| | PDF (468 KB)

Computer sensing of hand and limb motion is an important problem for applications in human-computer interaction (HCI), virtual reality, and athletic performance measurement. Commercially available sensors are invasive, and require the user to wear gloves or targets. We have developed a noninvasive vision-based hand tracking system, called DigitEyes. Employing a kinematic hand model, the DigitEyes ... View full abstract»

• ### Analyzing gait with spatiotemporal surfaces

Publication Year: 1994, Page(s):64 - 69
Cited by:  Papers (59)  |  Patents (3)
| | PDF (436 KB)

Human motions generate characteristic spatiotemporal patterns. We have developed a set of techniques for analyzing the patterns generated by people walking across the field of view. After change detection, the XYT pattern can be fit with a smooth spatiotemporal surface. This surface is approximately periodic, reflecting the periodicity of the gait. The surface can be expressed as a combination of ... View full abstract»

• ### 3D displacement field reconstruction on an irregular domain from planar tagged cardiac MR images

Publication Year: 1994, Page(s):172 - 177
Cited by:  Papers (6)
| | PDF (456 KB)

An important application of deformable motion estimation theory is the estimation of heart motion from tagged magnetic resonance image sequences. In tagged MR images, the heart appears with a spatially encoded pattern that moves with the tissue. The position of the tag pattern in each frame of the image sequence can be used to obtain sparse measurements of the heart's 3D displacement field. In thi... View full abstract»

• ### Spatio-temporal analysis of nonrigid motion from 4D data

Publication Year: 1994, Page(s):146 - 151
Cited by:  Papers (7)
| | PDF (440 KB)

Presents a method for analysis of nonrigid motion in time sequences of volume images (4D data). In this method, nonrigid motion of the deforming object's contour is dynamically approximated by a deformable surface. In order to reduce the number of parameters describing the deformation, we make use of modal analysis, which provides a spatial smoothing of the surface, and Fourier analysis of the tim... View full abstract»

• ### Simplifying multiple motion and structure analysis using planar parallax and image warping

Publication Year: 1994, Page(s):104 - 109
Cited by:  Papers (3)  |  Patents (11)
| | PDF (500 KB)

Presents a formulation for 3D motion and structure analysis using motion parallax defined with respect to an arbitrary plane in the environment. It is shown that if an image coordinate system is warped using plane projective transformation with respect to a reference view, the residual image motion is dependent only on the epipoles and has a simple relation to the 3D structure. Our computational s... View full abstract»