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Color indexing
 International Journal of Computer Vision
, 1991
"... Computer vision is embracing a new research focus in which the aim is to develop visual skills for robots that allow them to interact with a dynamic, realistic environment. To achieve this aim, new kinds of vision algorithms need to be developed which run in real time and subserve the robot's g ..."
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Cited by 1613 (26 self)
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Computer vision is embracing a new research focus in which the aim is to develop visual skills for robots that allow them to interact with a dynamic, realistic environment. To achieve this aim, new kinds of vision algorithms need to be developed which run in real time and subserve the robot's goals. Two fundamental goals are determining the location of a known object. Color can be successfully used for both tasks. This article demonstrates that color histograms of multicolored objects provide a robust, efficient cue for indexing into a large database of models. It shows that color histograms are stable object representations in the presence of occlusion and over change in view, and that they can differentiate among a large number of objects. For solving the identification problem, it introduces a technique called Histogram Intersection, which matches model and image histograms and a fast incremental version of Histogram Intersection, which allows realtime indexing into a large database of stored models. For solving the location problem it introduces an algorithm called Histogram Backprojection, which performs this task efficiently in crowded scenes. 1
Deformable Kernels for Early Vision
 IEEE Trans. Pattern Anal. Mach. Intell
, 1995
"... AbstractEarly vision algorithms often have a first stage of linearfiltering that ‘extracts ’ from the image information at multiple scales of resolution and multiple orientations. A common difficulty in the design and implementation of such schemes is that one feels compelled to discretize coarsel ..."
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Cited by 145 (11 self)
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AbstractEarly vision algorithms often have a first stage of linearfiltering that ‘extracts ’ from the image information at multiple scales of resolution and multiple orientations. A common difficulty in the design and implementation of such schemes is that one feels compelled to discretize coarsely the space of scales and orientations in order to reduce computation and storage costs. This discretization produces anisotropies due to a loss of translation, rotation, and scalinginvariance that makes early vision algorithms less precise and more difficult to design. This need not be so: one can compute and store efficiently the response of families of linear filters defined on a continuum of orientations and scales. A technique is presented that allows 1) computing the best approximation of a given family using linear combinations of a small number of ‘basis ’ functions; 2) describing all finitedimensional families, i.e., the families of filters for which a finite dimensional representation is possible with no error. The technique is based on singular value decomposition and may be applied to generating filters in arbitrary dimensions and subject to arbitrary deformations; the relevant functional analysis results are reviewed and precise conditions for the decomposition to be feasible are stated. Experimental results are presented that demonstrate the applicability of the technique to generating multiorientation multiscale 2D edgedetection kernels. The implementation issues are also discussed. Index TermsSteerable filters, wavelets, early vision, multiresolution image analysis, multirate filtering, deformable filters, scalespace I.
Multiscale Detection of Curvilinear Structures in 2D and 3D Image Data
, 1995
"... This paper presents a novel, parameterfree technique for the segmentation and local description of line structures on multiple scales, both in 2D and 3D. The algorithm is based on a nonlinear combination of linear filters and searches for elongated, symmetric line structures, while suppressing th ..."
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Cited by 106 (3 self)
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This paper presents a novel, parameterfree technique for the segmentation and local description of line structures on multiple scales, both in 2D and 3D. The algorithm is based on a nonlinear combination of linear filters and searches for elongated, symmetric line structures, while suppressing the response to edges. The filtering process creates one sharp maximum across the linefeature profile and across scalespace. The multiscale response reflects local contrast and is independent of the local width.
SteerableScalable Kernels for Edge Detection and Junction Analysis
 Image and Vision Computing
, 1992
"... Families of kernels that are useful in a variety of early vision algorithms may be obtained by rotating and scaling in a continuum a `template' kernel. These multiscale multiorientation family may be approximated by linear interpolation of a discrete finite set of appropriate `basis' ker ..."
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Cited by 91 (1 self)
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Families of kernels that are useful in a variety of early vision algorithms may be obtained by rotating and scaling in a continuum a `template' kernel. These multiscale multiorientation family may be approximated by linear interpolation of a discrete finite set of appropriate `basis' kernels. A scheme for generating such a basis together with the appropriate interpolation weights is described. Unlike previous schemes by Perona, and Simoncelli et al. it is guaranteed to generate the most parsimonious one. Additionally, it is shown how to exploit two symmetries in edgedetection kernels for reducing storage and computational costs and generating simultaneously endstop and junctiontuned filters for free.
A Fast Level Set based Algorithm for TopologyIndependent Shape Modeling
 Journal of Mathematical Imaging and Vision, special issue on Topology and
"... Shape modeling is an important constituent of computer vision as well as computer graphics research. Shape models aid the tasks of object representation and recognition. This paper presents a new approach to shape modeling which retains the most attractive features of existing methods, and overco ..."
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Cited by 45 (1 self)
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Shape modeling is an important constituent of computer vision as well as computer graphics research. Shape models aid the tasks of object representation and recognition. This paper presents a new approach to shape modeling which retains the most attractive features of existing methods, and overcomes their prominent limitations. Our technique can be applied to model arbitrarily complex shapes, which include shapes with significant protrusions, and to situations where no a priori assumption about the object's topology is made. A single instance of our model, when presented with an image having more than one object of interest, has the ability to split freely to represent each object. This method is based on the ideas developed by Osher & Sethian to model propagating solid/liquid interfaces with curvaturedependent speeds. The interface (front) is a closed, nonintersecting, hypersurface flowing along its gradient field with constant speed or a speed that depends on the curvature...
Motion without movement
 Computer Graphics
, 1991
"... We describe a technique for displaying patterns that appear to move continuously without changing their positions. The method uses a quadrature pair of oriented filters to vary the local phase, giving the sensation of motion. We have used this technique in various computer graphic and scientific vis ..."
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Cited by 43 (3 self)
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We describe a technique for displaying patterns that appear to move continuously without changing their positions. The method uses a quadrature pair of oriented filters to vary the local phase, giving the sensation of motion. We have used this technique in various computer graphic and scientific visualization applications.
X Vision: A Portable Substrate for RealTime Vision Applications
 Computer Vision and Image Understanding
, 1996
"... In the past several years, the speed of standard processors has reached the point where interesting problems requiring visual tracking can be carried out on standard workstations. However, relatively little attention has been devoted to developing visual tracking technology in its own right. In this ..."
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Cited by 43 (2 self)
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In the past several years, the speed of standard processors has reached the point where interesting problems requiring visual tracking can be carried out on standard workstations. However, relatively little attention has been devoted to developing visual tracking technology in its own right. In this article, we describe X Vision, a modular, portable framework for visual tracking. X Vision is designed to be a programming environment for realtime vision which provides high performance on standard workstations outfitted with a simple digitizer. X Vision consists of a small set of imagelevel tracking primitives, and a framework for combining tracking primitives to form complex tracking systems. Efficiency and robustness are achieved by propagating geometric and temporal constraints to the feature detection level, where image warping and specialized image processing are combined to perform feature detection quickly and robustly. Over the past several years, we have used X Vision to constr...
A Panorama on Multiscale Geometric Representations, Intertwining Spatial, Directional and Frequency Selectivity
, 2011
"... The richness of natural images makes the quest for optimal representations in image processing and computer vision challenging. The latter observation has not prevented the design of image representations, which trade off between efficiency and complexity, while achieving accurate rendering of smoot ..."
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Cited by 21 (8 self)
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The richness of natural images makes the quest for optimal representations in image processing and computer vision challenging. The latter observation has not prevented the design of image representations, which trade off between efficiency and complexity, while achieving accurate rendering of smooth regions as well as reproducing faithful contours and textures. The most recent ones, proposed in the past decade, share an hybrid heritage highlighting the multiscale and oriented nature of edges and patterns in images. This paper presents a panorama of the aforementioned literature on decompositions in multiscale, multiorientation bases or dictionaries. They typically exhibit redundancy to improve sparsity in the transformed domain and sometimes its invariance with respect to simple geometric deformations (translation, rotation). Oriented multiscale dictionaries extend traditional wavelet processing and may offer rotation invariance. Highly redundant dictionaries require specific algorithms to simplify the search for an efficient (sparse) representation. We also discuss the extension of multiscale geometric decompositions to nonEuclidean domains such as the sphere or arbitrary meshed surfaces. The etymology of panorama suggests an overview, based on a choice of partially overlapping “pictures”.
Demosaicing of Color Images Using Steerable Wavelets
 HP Labs Israel, Tech. Rep. HPL2002206R1 20020830, 2002. [Online]. Available: citeseer.nj.nec.com/548392.html
, 1997
"... In some types of digital color cameras only a single value is provided for each pixel: either, red, green, or blue. The reconstruction of the three color values for each pixel is known as the "demosaicing" problem. This report suggests a solution to this problem based on the steerable w ..."
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Cited by 20 (3 self)
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In some types of digital color cameras only a single value is provided for each pixel: either, red, green, or blue. The reconstruction of the three color values for each pixel is known as the "demosaicing" problem. This report suggests a solution to this problem based on the steerable wavelet decomposition. The reconstructed images present a faithful interpolation of missing data while preserving edges and textures.
Mechanisms For Motion Perception
, 1991
"... RE 1. a: An image of a vase moving to the right. b: A sequence of frames may be piled up to form a flip book; time is the third dimension. c: A skeleton view of the (x,y,t) volume helps suggest its structure. d: The spacetime volume may be sliced to illustrate the fact that the motion is equivalent ..."
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Cited by 8 (0 self)
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RE 1. a: An image of a vase moving to the right. b: A sequence of frames may be piled up to form a flip book; time is the third dimension. c: A skeleton view of the (x,y,t) volume helps suggest its structure. d: The spacetime volume may be sliced to illustrate the fact that the motion is equivalent to spatiotemporal orientation. e: In the case of continuous motion, the volume is densely filled. The moving vase traces out an extruded shape that is sheared due to the motion. O (a) (b) (c) (d) (e) x t y x t y x t y x To get a better understanding of the structure of the spacetime volume, we can cut a slice through it in an (x,t) plane, as illustrated in Figure 1d. The vase traces out an extruded shape that is sheared due to the motion. In the case of continuous motion, the spatiotemporal volume is densely filled, as shown in Figure 1e. The (x,t) slice is slanted as a result of the rightward motion. Figure 2a shows an (x,y,t) volume taken from a video sequence showing a