scispace - formally typeset
Search or ask a question
Journal Article•DOI•

Representation of contours and regions for efficient computer search

01 Feb 1973-Communications of The ACM (ACM)-Vol. 16, Iss: 2, pp 69-82
TL;DR: A novel computer-searchable representation for the three basic pictorial features, contour maps, region coverage, and line structures, is described, which provides a rapid means of searching large files for data associated with geometric position as well as with attribute value.
Abstract: A novel computer-searchable representation for the three basic pictorial features, contour maps, region coverage, and line structures, is described. The representation, which has practical storage requirements, provides a rapid means of searching large files for data associated with geometric position as well as with attribute value. An application of this representation to handling terrain information illustrates its utility. The algebraic properties of the data structure make it computationally easy to determine whether a point lies within a closed boundary; compute the area contained by a closed boundary; generate the closed boundary representing the union or intersection of two closed boundaries; and determine the neighboring boundaries to a point and the minimum distances between them and the point.
Citations
More filters
Journal Article•DOI•
TL;DR: L'accentuation est mise sur la representation de donnees dans les applications de traitement d'images, d'infographie, les systemes d'informations geographiques and the robotique.
Abstract: Apercu sur les quadarbres et les structures de donnees hierarchiques. Elles sont basees sur le principe de decomposition recursive. L'accentuation est mise sur la representation de donnees dans les applications de traitement d'images, d'infographie, les systemes d'informations geographiques et la robotique. On examine en detail un certain nombre d'operations dans lesquelles de telles structures de donnees trouvent leur utilisation

2,273 citations


Cites methods from "Representation of contours and regi..."

  • ...Other popular representations include ras- ter-oriented methods [Merrill 1973; Peu- quet 1979], as well as a combination of vectors and rasters {e.g., vasters [Peuquet 1983])....

    [...]

  • ...Other popular representations include raster-oriented methods [Merrill 1973; Peuquet 1979], as well as a combination of vectors and rasters (e....

    [...]

Journal Article•DOI•
Herbert Freeman1•
TL;DR: Various forms of line drawing representation are described, different schemes of quantization are compared, and the manner in which a line drawing can be extracted from a tracing or a photographic image is reviewed.
Abstract: This paper describes various forms of line drawing representation, compares different schemes of quantization, and reviews the manner in which a line drawing can be extracted from a tracing or a photographic image. The subjective aspects of a line drawing are examined. Different encoding schemes are compared, with emphasis on the so-called chain code which is convenient for highly irregular line drawings. The properties of chain-coded line drawings are derived, and algorithms are developed for analyzing line drawings to determine various geometric features. Procedures are described for rotating, expanding, and smoothing line structures, and for establishing the degree of similarity between two contours by a correlation technique. Three applications are described in detail: automatic assembly of jigsaw puzzles, map matching, and optimum two-dimensional template layout

1,485 citations

Journal Article•DOI•
01 Jul 1992
TL;DR: Both template matching and structure analysis approaches to R&D are considered and it is noted that the two approaches are coming closer and tending to merge.
Abstract: Research and development of OCR systems are considered from a historical point of view. The historical development of commercial systems is included. Both template matching and structure analysis approaches to R&D are considered. It is noted that the two approaches are coming closer and tending to merge. Commercial products are divided into three generations, for each of which some representative OCR systems are chosen and described in some detail. Some comments are made on recent techniques applied to OCR, such as expert systems and neural networks, and some open problems are indicated. The authors' views and hopes regarding future trends are presented. >

892 citations

Journal Article•DOI•
TL;DR: A regular decomposition of picture area into successively smaller quadrants is defined, which involves logarithmic search, and the resulting picture representation is shown to enable rapid access of image data without regard to position, efficient storage, and approximate structural descriptions of constituent patterns.

290 citations

Journal Article•DOI•
TL;DR: This framework is used to provide clarification of how varying data models, as well as their inherent advantages and disadvantages, are interrelated, and provides an insight into how these conflicting demands may be balanced in a more systematic and predictable manner for practical applications.
Abstract: This paper examines the major types of spatial data models currently known and places these models in a comprehensive framework. This framework is used to provide clarification of how varying data models, as well as their inherent advantages and disadvantages, are interrelated. It also provides an insight into how these conflicting demands may be balanced in a more systematic and predictable manner for practical applications, and reveals directions for needed future research. On examine les principaux types de modeles de donnees spatiales actuels, et on les place dans un cadre global. Ce cadre est utilise pour eclaircir comment ces divers modeles spatiaux, de meme que leurs avantages et desavantages, sont interrelies. Le cadre laisse aussi voir comment ces demandes contradictoires peuvent etre equilibrees d'une facon plus systematique et previsible pour des applications pratiques, et revele les directions que doit prendre la recherche future.

268 citations

References
More filters
Journal Article•DOI•
Herbert Freeman1•
TL;DR: It is shown that one can determine through the use of relatively simple numerical techniques whether a given arbitrary plane curve is open or closed, whether it is singly or multiply connected, and what area it encloses.
Abstract: A method is described which permits the encoding of arbitrary geometric configurations so as to facilitate their analysis and manipulation by means of a digital computer. It is shown that one can determine through the use of relatively simple numerical techniques whether a given arbitrary plane curve is open or closed, whether it is singly or multiply connected, and what area it encloses. Further, one can cause a given figure to be expanded, contracted, elongated, or rotated by an arbitrary amount. It is shown that there are a number of ways of encoding arbitrary geometric curves to facilitate such manipulations, each having its own particular advantages and disadvantages. One method, the so-called rectangular-array type of encoding, is discussed in detail. In this method the slope function is quantized into a set of eight standard slopes. This particular representation is one of the simplest and one that is most readily utilized with present-day computing and display equipment.

1,751 citations

Proceedings Article•DOI•
12 Nov 1963
TL;DR: A hybrid simulator that exploits both the redundancy in the terrain and the repetitiveness caused by the radar scan pattern is described, which affords reductions of 103 in storage capacity and computation speed.
Abstract: This paper summarizes results of a study of the design and application of special-purpose computers for the simulation of air-to-ground radars. Specifically, the computers must generate information in real-time to simulate the display of a scanning radar in a vehicle flying at Mach 3 and arbitrary altitude. The radar can view 105 square miles of terrain per second with a resolution of 60 points per mile in range (five per microsecond). This paper describes a hybrid simulator that exploits both the redundancy in the terrain and the repetitiveness caused by the radar scan pattern. An overall design is presented that affords reductions of 103 in storage capacity and computation speed, compared with a straightforward digital approach for generation of topographic profiles from which the display is prepared. Details are presented of data formats and transfer schemes through the memory hierarchy, and of algorithms for the reconstruction of analog profiles from a digitally stored contour map.

119 citations


"Representation of contours and regi..." refers background in this paper

  • ...Elevation contours were encoded with COPIER such that the systems of concentric contours (21, 20, 19, 18, 17, 16), (15, 14), (13, 12, 11, 10, 9), (8, 7, 6), (5, 6, 4, 3, 2) were represented....

    [...]

  • ...(3), note that the 3 and 5 elements are equivalent to the 3 and 5 contour labels appearing earlier in the sequence....

    [...]

  • ...~, 6, 7, 5, J~, 8, 9, 5, 10, 11, U) (3)...

    [...]

Proceedings Article•DOI•
01 Jan 1967
TL;DR: The rest of this paper is concerned with the basic requirements of the data structure package, and with a survey of those packages which have been implemented and about which information is available.
Abstract: The aim of Computer Aided Design is to create in the computer a model of the design problem. For example, an electronic circuit may be being designed; the engineer will use an environment consisting of standard circuit parts, with the laws that govern the operation, and will use this environment, together with the constraints on performance, to build a model which is his proposed solution to the design problem. This model may now be tested against the specification and will generally be modified iteratively until the design goal is achieved, in this case a layout with the required characteristics. It may also be that the design problem is being tackled by a team, in which case several users of the design system may wish to access and transform the model, for instance to display views and projections of it, or check on how it interfaces with a parallel project.The rest of this paper is concerned with the basic requirements of the data structure package, and with a survey of those packages which have been implemented and about which information is available.

67 citations


Additional excerpts

  • ...Elevation contours were encoded with COPIER such that the systems of concentric contours (21, 20, 19, 18, 17, 16), (15, 14), (13, 12, 11, 10, 9), (8, 7, 6), (5, 6, 4, 3, 2) were represented....

    [...]

  • ...Y~ = (6, 13, 13, 16, 16, 17, 18), Y~3 = (8, - - 1 , 0 , 0 , 19 ,20 ,21 ,22 ,23 ) ....

    [...]

Journal Article•DOI•
H. Freeman1, S.P. Morse2•
TL;DR: This paper proposes a efficient search strategy, suitable for programming on a digital computer, which will yield the solution in a reasonable time when locating the ground track of an aircraft, given the elevation of the terrain below the aircraft during flight.
Abstract: Ground track location on contour map for given terrain elevation profile, using digital computer

65 citations

Journal Article•DOI•
Stephen P. Morse1•
TL;DR: Generalized techniques are developed whose use can simplify the solution of problems relating to contour maps and have been applied to the problem of locating the ground track of an aircraft from elevation readings obtained during a flight.
Abstract: Generalized techniques are developed whose use can simplify the solution of problems relating to contour maps. One of these techniques makes use of the topological properties of contour maps. The topology is represented by a graphical structure in which adjacent contour lines appear as connected nodes. Another generalized technique consists of utilizing geometrical properties to determine the characteristics of straight lines drawn on the contour map. Both of these techniques have been applied to the problem of locating the ground track of an aircraft from elevation readings obtained during a flight.

50 citations