WorldCat Identities

Hildreth, Ellen Catherine

Overview
Works: 27 works in 49 publications in 1 language and 400 library holdings
Genres: Bibliography 
Roles: Author
Classifications: BF241, 153.754
Publication Timeline
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Most widely held works by Ellen Catherine Hildreth
The measurement of visual motion by Ellen Catherine Hildreth( Book )

11 editions published between 1982 and 1984 in English and held by 297 WorldCat member libraries worldwide

The analysis of visual motion divides naturally into two stages: the first is the measurement of motion, for example, the assignment of direction and magnitude of velocity to elements in the image, on the basis of the changing intensity pattern; the second is the use of motion measurements, for example, to separate the scene into distinct objects, and infer their three-dimensional structure. In this paper, we present a computational study of the measurement of motion. Similar to other visual processes, the motion of elements is not determined uniquely by information in the changing image; additional constraint is required to compute a unique velocity filed. Given this global ambiguity of motion. Local measurements from the changing image, such as those provided by directionally-selective simple cells in primate visual cortex, cannot possibly specify a unique local velocity vector, and in fact, specify only one component of velocity. Computation of the full two-dimensional velocity field requires the integration of local motion measurements, either over an area, or along contours in the image. We will examine possible algorithms for computing motion, based on a range of additional constraints. Finally, we will present implications for the biological computation of motion
Know Alabama! The geology and mineral resources of Alabama by Ellen Catherine Hildreth( Book )

1 edition published in 1942 in English and held by 48 WorldCat member libraries worldwide

Implementation of a theory of edge detection by Ellen Catherine Hildreth( )

2 editions published in 1980 in English and held by 9 WorldCat member libraries worldwide

Theory of edge detection by David Marr( Book )

2 editions published in 1979 in English and held by 7 WorldCat member libraries worldwide

A theory of edge detection is presented. (1) Intensity changes, which occur in a natural image over a wide range of scales, are detected separately at different scales. At a given scale, this is best done by finding the zero-crossings of gradient-squared G(x, y) * (I(x, y) for image I, where G(x, y) is a two-dimensional gaussian distribution, and gradient-squared is the Laplacian. (2) The physical phenomena that give rise to the intensity changes are localized. This allows one to construct rules for combining information from the different scales into a primitive description of the image. A physiological model for zero-crossing detection is proposed. (Author)
The computational study of vision by Ellen Catherine Hildreth( Book )

2 editions published in 1988 in English and held by 4 WorldCat member libraries worldwide

Through vision, we derive a rich understanding of what is in the world, where objects are located, and how they are changing with time. Because we obtain this understanding immediately, effortlessly, and without conscious introspection, we can be deceived into thinking that vision should therefore be a fairly simple task to perform. The computational approach to the study of vision inquires directly into the sort of information processing needed to extract important information from the changing visual image - information such as the three-dimensional (3-D) structure and movement of objects in the scene, or the color and texture of object surfaces. An important contribution that computational studies have made is to show how difficult vision is to perform, and how complex are the processes needed to perform visual tasks successfully. This article reviews some computational studies of vision, focusing on edge detection, binocular stereo, motion analysis, intermediate vision and object recognition. Keywords: Computer vision; Vision; Binocular stereo vision; Motion analysis; Object recognition; Pattern recognition. (KT)
The perceptual buildup of three-dimensional structure from motion( Book )

2 editions published in 1989 in English and held by 4 WorldCat member libraries worldwide

We present a set of psychophysical experiments that measure the accuracy of perceived three-dimensional structure derived from relative motion in the changing two-dimensional image. The experiments are motivated in part by a computational model proposed by Ullman (1984), called the incremental rigidity scheme, in which an accurate 3-D structure is built up incrementally, by considering images of moving objects over an extended time period. Our main conclusions are: first, the human visual system can derive an accurate model of the relative depths of moving points, even in the presence of noise in their image positions; second, the accuracy of the 3-D model improves with time, eventually reaching a plateau; and third, the 3-D structure currently perceived appears to depend on previous 3-D models. Through computer simulations, we relate the results of our psychophysical experiments with the predictions of Ullman's model. (kr)
Edge detection by Ellen Catherine Hildreth( Book )

1 edition published in 1985 in English and held by 4 WorldCat member libraries worldwide

Abstract: "For both biological systems and machines, vision begins with a large and unwieldly array of measurements of the amount of light reflected from surfaces in the environment. The goal of vision is to recover physical properties of objects in the scene, such as the location of object boundaries and the structure, color and texture of object surfaces, from the two-dimensional image that is projected onto the eye or camera. This goal is not achieved in a single step; vision proceeds in stages, with each stage producing increasingly more useful descriptions of the image and then the scene. The first clues about the physical properties of the scene are provided by the changes of intensity in the image
Recovering heading for visually-guided navigation by Ellen Catherine Hildreth( Book )

2 editions published in 1991 in English and held by 3 WorldCat member libraries worldwide

We present a model for recovering the direction of heading of an observer who is moving relative to a scene that may contain self-moving objects. The model builds upon an algorithm proposed by Rieger and Lawton (1985), which is based on earlier work by Longuet-Higgins and Prazdny (1981). The algorithm uses velocity differences computed in regions of high depth variation to estimate the location of the focus of expansion, which indicates the observer's heading direction. We relate the behavior of the proposed model to psychophysical observations regarding the ability of human observers to judge their heading direction, and show how the model can cope with self-moving objects in the environment. We also discuss this model in the broader context of a navigational system that performs tasks requiring rapid sensing and response through the interaction of simple task specific routines
The spontaneous combustion of dreams : poetry of Detroit by Ellen Catherine Hildreth( Book )

1 edition published in 1994 in English and held by 3 WorldCat member libraries worldwide

The computational approach to vision and motor control by Ellen Catherine Hildreth( Book )

3 editions published in 1985 in English and held by 2 WorldCat member libraries worldwide

Monk's House by Ellen Catherine Hildreth( Book )

1 edition published in 1998 in English and held by 2 WorldCat member libraries worldwide

Evidence for a fifth, smaller channel in early human vision by David Marr( Book )

2 editions published between 1979 and 1980 in English and held by 2 WorldCat member libraries worldwide

Computation of Stereo and Visual Motion: From Biophysics to Psychophysics( Book )

1 edition published in 1988 in English and held by 1 WorldCat member library worldwide

During the second and third quarter of this stretchout year of funding, we have continued to explore a number of problems in motion analysis, including the parallel detection of motion using a correlation-based mechanism, motion correspondence, neural mechanisms for motion detection and measurement, and the recovery of 3-D structure and motion. We are also starting to focus more deeply on the integration of multiple visual cues. Described here is some work on the interaction between surface shape, albedo, and the illuminant direction. As we noted in our previous report, we are developing and testing some variations on a parallel network model recently proposed by Hutchinson, Koch, Luo and Mead for combining the computation of the smoothest velocity field with line processes (suggested by Geman and Geman) for handling motion discontinuities. Our modified network derives the initial motion measurements only at the locations of significant intensity changes, allows greater flexibility in the placement of the discontinuities and considers variations on the energy function being minimized to implement the smoothness constraint. The network is also designed in a way that more closely parallels physiological properties of motion-sensitive neurons in area MT of monkey visual cortex. (jes)
The computation of the velocity field by Ellen Catherine Hildreth( Book )

3 editions published in 1983 in English and held by 1 WorldCat member library worldwide

Eight images : the Bettina poems by Ellen Catherine Hildreth( Book )

1 edition published in 1996 in English and held by 1 WorldCat member library worldwide

The incremental rigidity scheme for recovering structure from motion--position vs. velocity based formulations by N. M Grzywacz( Book )

2 editions published in 1985 in English and held by 1 WorldCat member library worldwide

Evidence for a Fifth, Smaller Channel in Early Human Vision( Book )

1 edition published in 1979 in English and held by 1 WorldCat member library worldwide

Recent studies in psychophysics and neurophysiology suggest that the human visual system utilizes a range of different size or spatial frequency tuned mechanisms in its processing of visual information. It has been proposed that there exist four such mechanisms, operating everywhere in the visual field, with the smallest mechanism having a central excitatory width of 3 in. of arc in the central fovea. This note argues that there exists indirect evidence for the existence of a fifth, smaller channel, with a central width in the fovea of 1.5 in. (Author)
Computations underlying the measurement of visual motion by Ellen Catherine Hildreth( Book )

1 edition published in 1984 in English and held by 1 WorldCat member library worldwide

The analysis of visual motion: from computational theory to neuronal mechanisms by Ellen Catherine Hildreth( Book )

1 edition published in 1986 in English and held by 1 WorldCat member library worldwide

This paper reviews a number of aspects of visual motion analysis in biological systems, from a computational perspective. We illustrate the kinds of insights that have been gained through computational studies and how those observations can be integrated with experimental studies from psychology and the neurosciences, to understand the particular computations used by biological systems to analyze motion. The particular areas of motion analysis that we discuss include early motion detection and measurement, the optical flow computation, motion correspondence, the detection of motion discontinuities, and the recovery of three-dimensional structure from motion. Keywords: Image analysis, Artificial intelligence
Know Alabama! : the Geology and Mineral Resources of Alabama ; a bibliography for schools by Ellen Catherine Hildreth( Book )

1 edition published in 1942 in English and held by 1 WorldCat member library worldwide

 
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Alternative Names
Hildreth, E.

Hildreth, E. (Ellen)

Languages
English (41)