Emergency response requires strategic assessment of risks, decisions, and communications that are timecritical while requiring teams of individuals to have fast access to large volumes of complex information and technologies that enables tightly coordinated work. The access to this information by crisis management (CM) teams in emergency operations centers can be facilitated through various humancomputer interfaces. Unfortunately these interfaces are hard to use, require extensive training, and often impede rather than support teamwork. Dialogue-enabled devices, based on natural, multimodal interfaces have the potential of making a variety of information technology tools accessible during crisis management. This paper establishes the importance of multimodal interfaces in various aspects of crisis management and explores many issues in realizing successful speech-gesture driven, dialog-enabled interfaces for CM. The paper

This paper presents a feature tracker for long image sequences based on simultaneously estimating the motions and deformations of a collection of adjacent image patches. By sharing common corner nodes, the patches achieve greater stability than independent patch trackers. Modeling full bilinear deformations enables tracking in sequences which have large non-translational motions and/or foreshortening effects. We demonstrate the advantages of our technique with respect to previous algorithms using experimental results. Keywords: motion analysis, multiframe feature tracking, affine patches c flDigital Equipment Corporation 1995. All rights reserved. 1 The Robotics Institute, Carnegie Mellon University, Pittsburgh, PA 15213-3890 Contents i Contents 1 Introduction : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1 2 Previous work : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1 3 Spline-based image registration : : : : : : : :...

A new edge--based approach for efficient image registration is proposed. The proposed approach applies wavelet transform to extract a number of feature points as the basis for registration. Each selected feature point is an edge point whose edge response is the maximum within a neighborhood. By using a line--fitting model, all the edge directions of the feature points are estimated from the edge outputs of a transformed image. In order to estimate the orientation difference between two partially overlapping images, a so--called "angle histogram" is calculated. From the angle histogram, the rotation angle which can be used to compensate for the difference between two target images can be decided by seeking the angle that corresponds to the maximum peak in the histogram. Based on the rotation angle, an initial matching can be performed. During the real matching process, we check each candidate pair in advance to see if it can possibly become a correct matching pair. Due to this checking,...

Image stabilization can be used as a front-end system for many tasks that require dynamic image analysis, such as navigation and tracking of independently moving objects from a moving platform. We present a fast and robust electronic digital image stabilization system that can handle large image displacements based on a two-dimensional feature-based multi-resolution motion estimation technique. The method tracks a small set of features and estimates the movement of the camera between consecutive frames. Stabilization is achieved by combining all motion from a reference frame and warping the current frame back to the reference. The system has been implemented on parallel pipeline image processing hardware (a Datacube MaxVideo 200) connected to a SUN SPARCstation 20/612 via a VME bus adaptor. Experimental results using video sequences taken from a camera mounted on a vehicle moving on rough terrain show the robustness of the system while running at approximately 20 frames per second. 0 ...

. Retinal image motion and optical ow as its approximation are fundamental concepts in the eld of vision, perceptual and computational. However, the computation of optical ow remains a challenging problem as image motion includes discontinuities and multiple values mostly due to scene geometry, surface translucency and various photometric eects such as reectance. In this contribution, we analyze image motion in the frequency space with respect to motion discontinuities and translucence. We derive the frequency structure of motion discontinuities due to occlusion and we demonstrate its various geometrical properties. The aperture problem is investigated and we show that the information content of an occlusion almost always disambiguates the velocity of an occluding signal suering from the aperture problem. In addition, the theoretical framework can describe the exact frequency structure of Non-Fourier motion and bridges the gap between Non-Fourier visual phenomena and their understanding in the frequency domain. Keywords: Image motion, optical ow, occlusion, aperture problem, non-Fourier motion 1.

Three different algorithms for obstacle detection are presented in this paper each based on different assumptions. The first two algorithms are qualitative in that they return only yes/no answers regarding the presence of obstacles in the field of view; no 3D reconstruction is performed. They have the advantage of fast determination of the existence of obstacles in a scene based on the solvability of a linear system. The first algorithm uses information about the ground plane, while the second only assumes that the ground is planar. The third algorithm is quantitative in that it continuously estimates the ground plane and reconstructs partial 3D structures by determining the height above the ground plane of each point in the scene. Experimental results are presented for real and simulated data, and the performance of the three algorithms under different noise levels is compared in simulation. We conclude that in terms of the robustness of performance, the third algorithm is ...

Our world is three-dimensional, considering time as additional dimension, even four-dimensional. Despite most approaches in vision-based driver assistance have utilized greylevel or color image sequences. Since the spatial arrangement of scene objects is often more relevant than the re#ected brightness information, there has been an increasing interest in range sensors for collision avoidance systems recently. This paper presents an approach to obstacle tracking in range image sequences of tra#c scenes. Our tracking scheme uses a feature-based approach. To #nd correspondences between features in consecutive frames we strongly make use of the three-dimensional sensory information. Thus we are also able to handle the most general case in matching, the m:n matching. Alternative feature assignments are kept for selecting the most optimal consistent subset of assignments. Further temporally global processes such as aging, the prediction of 3D positions and merge of similar moving obstacles ...

Retinal image motion and optical flow as its approximation are fundamental concepts in the field of vision, perceptual and computational. However, the computation of optical flow remains a challenging problem as image motion includes discontinuities and multiple values mostly due to scene geometry, surface translucency and various photometric effects such as surface reflectance. In this contribution, we analyze image motion in the frequency space with respect to motion discontinuities and surface translucence. We derive, under models of constant and linear optical flow, the frequency structure of motion discontinuities due to occlusion and we demonstrate its various geometrical properties. The aperture problem is investigated and we show that the information content of an occlusion almost always disambiguates the velocity of an occluding signal suffering from the aperture problem. In addition, the theoretical framework can describe the exact frequency structure of Non-Fourier motion an...

this article is to consider the domain of feature tracking and to complement previous works by addressing the scale problems arising in this context. In most previous works, the analysis is performed at a single predetermined scale, and this may can cause severe problems if the size of image structures change over time due to expansions or contractions. We will show how an explicit mechanism for automatic scale selection can be included in a feature tracker to handle tracking situations in which the size variations are large. Besides avoiding explicit setting of scale levels for feature detection, and thus overcoming some of the very fundamental limitations of processing image sequences at a single scale, it will be demonstrated how scale levels selected by a scale selection procedure are useful for adapting the window size for correlation and as a matching cue. It will also be illustrated how an appropriate choice of temporal scale can improve the performance. Fixed scale tracking Adaptive scale tracking Fig. 1. Illustration of the importance of automatic scale selection when tracking image structures over time. A fixed scale tracker fails early when the size variations are large (left), whereas all visible blobs are correctly tracked up to the last image when a mechanism for adaptive scale selection has been included (right). 2 The need for automatic scale selection in tracking

This paper presents a new algorithm of disparity map segmentation in planar facets. Originalities of this method lies in the process of dense disparity map estimation, using the dynamic programming subject to interest points previously extracted. The segmentation of this map uses the normal vector at each pixel surface. The matching of pixels between the two images by dynamic programming provides us with a scattered disparity map. So the densification of this map is achieved by matching contour points extracted between the two available images. Experiments with real images have validated our method and have clearly shown the improvement over the existing methods. The dense disparity map obtained is reliable when compared to classical methods. We also get a normal vector map segmented in contours and in homogeneous regions reflecting 3D planar facets.