Showing papers on "Line segment published in 1980"

Syntactic Approach to ECG Rhythm Analysis

Abstract: A diagnostic system for ECG rhythm monitoring based on syntactic approaches to pattern recognition is presented here. The method proposed exploits the difference in shape and structure between arrhythmic and normal ECG patterns to generate distinctly different descriptions in terms of a chosen set of primitives. A given frame of signal is first approximated piecewise linearly into a set of line segments which are completely specified in terms of their length and slope values. The slope values are quantized into seven distinct levels and a unit-length line segment with a slope value in each of these levels is coded as a slope symbol. Seven such slope symbols constitute the set of primitives. The given signal is represented as a string of such symbols based on the length and angle of the line segments approximating the signal. Context-free languages are used for describing the classes of abnormal and normal ECG patterns considered here. Analysis of actual ECG data shows efficiency comparable with that of existing methods and a saving in processing time.

Method and apparatus for generating line segments and polygonal areas on a raster-type display

Abstract: A method and apparatus utilizes information describing linear line segments in terms (1) the horizontal scan line scan at which the line segment originates, (2) the horizontal position within the line of the point of origin, (3) the direction of the line segment, and (4) the horizontal scan line at which the line segment terminates to generate line segment information on a raster-scan type video display. The line segments can be combined to form polygonal areas that are capable of movement and changes in size or shape on the display.

Line recognition method

Abstract: In a pattern recognition apparatus for recognizing a pattern including a line pattern consisting of a plurality of line segments, there is proposed a line recognition method which comprises steps of: recognizing the coordinates of end points of each of segments constituting a line pattern; employing the coordinates of an end point of a first line segment as base point coordinates; deciding whether the distance between the base point and an end point of a second line segment is less than a certain value or not; employing as a suitable point the end point of the second line segment with said distance being less than the certain value; and selecting a connectable second line segment and connecting said suitable point to the base point of the first line segment.

Switched delay line for steerable null antenna system

Abstract: The delay line has a number of sections in tandem. Each section comprises o line segments in parallel, one of which is relatively short and the other of a length to provide a given differential delay for the section. Each segment has a PIN diode at each end, poled in one direction for the short segment and in the other direction for the other. The bias arrangement for the PIN diodes includes four transistor switches in a bridge, with a selected pair in opposite legs turned on to cause a polarity which permits it to flow through only that segment in which the PIN diodes are forward biased. The given differential delay for the several sections has a binary relation.

A Geometric Method for Approximating Convex Arcs

Abstract: Approximating a curve by a sequence of points along it is a problem of importance in such traditional fields as surveying and in such modern ones as computer graphics The authors examine a simple geometric method for choosing points $p_1 , \cdots ,p_n $ along a planar convex curve; the point $p_{i + 1} $ is chosen so that the line segment $I(p_{i - 1,} p_{i + 1} )$ is parallel to a support line of the curve at $p_i $ This method tends to produce many points where the curvature is large and few points where the curvature is small, and thus it permits an accurate representation of the curve from limited information The points of the approximating sequence can be generated in a mechanical manner from two succeeding terms, and mild regularity conditions on the curve insure that the sequence will be finite

A Preliminary Examination of End Effects in Polyelectrolyte Theory: The Potential of a Line Segment of Charge

Abstract: The potential, ICT, of a line segment of charge is calculated in the Debye-Huckel approximation We determine ICT as a function of segment length and the position of the test charge If the test charge is near the line segment and the length of the line segment of charge is large relative to the screening length, qT is well approximated by the electrostatic potential of an infinite line of charge When the test charge is far from the line segment, qT reduces to the point charge limit Recently, considerable attention has been devoted to elucidating the properties of the line of charge model of polyelectrolyte The infinitely long line of charge model has been employed to calculate the colligative properties of dilute polyelectrolyte the diffu- sion constant of a mobile ion in the presence of a polye- lectr~lyte,~,~ and the expansion parameter, 2, of the ex- cluded volume theory6 We note, however, that real po- lyions are of finite size; as such, it would be quite useful to determine the magnitude of end effects on the elec- trostatic potential arising from a finite line of charge Hence, a partial motivation of the present work is to de- termine when the replacement of the potential of the line segment of charge by that of an infinite line is justified and when it is not We also note that the line segment of charge may perhaps be a plausible model for low molecular weight DNA and helical poly(g1utamic acid) at low to moderate ionic strengths Thus, this paper is a preliminary step toward understanding the dependence of polyelec- trolyte behavior on chain length If the length of the line segment of charge is large rel- ative to the screening length and if the test charge is near the source, it seems intuitively reasonable that the elec- trostatic potential should be well approximated by the infinite line of charge result However, when the test charge is far from the line segment of charge, the line segment should appear as a point charge In the context of the Debye-Huckel approximation, verification of the above conjectures will be presented in what follows Consider a uniformly charged line segment of length L immersed in bulk solvent It is assumed that each infin- itesmal piece interacts with the test charge via a screened Coulomb potential For discussions concerning the ap- plicability of an effective charge density and counterion condensation, we refer to the literat~re'-~,~ -~ Let the line segment of charge lie on the z axis, in the cylindrical coordinate system (r,O,z), and let one end of the line segment be located at z = 0 Whereupon, the poten- tial, #T, felt at a point r = (r,B,z) by a test charge is given by @ L exp(-K(r2 + (z - z')~)~/~)

The moments of coverage of a linear set

Abstract: A number of points are chosen at random along a line segment and used as the left end-points of lengths of fixed size. Finite sum expressions are derived for the moments of the portion of the line segment covered by one or more of the lengths. The derivation utilizes a relationship L i ween the coverage and the busy time in an M/D/oo queue. LINEAR SET; COVERAGE; MOMENTS

Context dependence in visual feature processing

Abstract: Dependence in visual feature processing was studied with two identification experiments using briefly exposed stimuli The basic stimuli consisted of two orthogonal line segments which formed either one of the four angles of a square, and the subject had to identify the location of the horizontal and vertical line segment making up a stimulus In the first experiment, the two orthogonal line segments were sometimes separated by a gap In the second experiment, either a 45° diagonal or a 135° diagonal or both were added to the right angles With the observed response frequencies two forms of independence in feature detection were tested Feature detection is called state independent if the detection of a feature is independent of the detection of another feature According to context independence the detection of a feature is independent of the orientation and location of other features in the stimulus Feature detection was shown to be context dependent whereas the hypothesis of state independence was not rejected, and state independence was unrelated to the size of the gap between the two orthogonal line segments in the first experiment It was argued that the context effects obtained (context dependence) had occurred early in processing during the automatic activation of representational units corresponding to features before controlled search, interpretation and decision processes became involved

Automatic line segment generator for use with linear array display devices

Abstract: An automatic line segment generator is disclosed primarily for use with linear array display devices. Converted analog data is received from a single slope analog to digital converter. This received digital data is synchronized with a system clock and is positioned and stored as line segment data during one measurement period of the analog to digital converter. New data is received during the next measurement period and is then synchronized, positioned and compared against the previously stored line segment data. The length of the line segment in storage will remain the same or increase based on the position and length of the newly received data, i.e. if the new data position is within the stored data position, the stored data remains the same and if the new data position is outside of the stored data position, the stored data length will increase to the new data position.

A system for printing an image of a signature on a matrix printer

Abstract: The specification describes a system for printing an image of a signature on a matrix printer (25) of the kind normally used for printing vertically spaced lines of alphanumeric characters by energizing successive selected combinations of dot printing elements carried by a print head as the latter is scanned line by line across a record medium, each selected combination of printing elements causing a corresponding vertical array of dots to be printed on the record medium, and being defined by a corresponding binary bit pattern (hereinafter referred to as a vertical bit slice) presented to the printer control circuitry. When using such a printer for printing an image of a signature binary information representing a signature image to be printed is presented to the printer (25) in a format which contains: a first portion of binary information defining the area of the record medium required to accommodate the signature image, the height of the area being defined as a number of substantially vertically contiguous print lines and the length of each line of the area being defined as a number of equal length line segments each corresponding to a predetermined number of vertical bit slices, a second portion of binary information which, in respect of each line, defines those line segments which are to contain a part of the signature image and those line segments which are blank, and a third portion of binary information which, in respect of each line, contains the vertical bit slices in sequence for those line segments which are to contain a portion of the signature image. The printer control circuitry comprises means responsive to the above format of binary information for printing, in respect of each line defined by the first portion of binary information, the vertical dot patterns corresponding to the vertical bit slices of the third portion of binary information in those line segments defined by the second portion of binary information as containing a part of the signature image, the print head being controlled to move through the blank line segments of each line relatively rapidly compared to its movement through the line segments in which vertical dot patterns are printed, and the record medium being controlled for vertically indexing in such. manner that the successive lines are printed substantially contiguously.

Edge Linking Using Thresholding

Abstract: Edge detection followed by thinning produces a set of points which lie along edges in the original image. It is important to link together the pixels which lie along the same edge. The resulting associated groups can then be fitted with line segments. This paper presents a new technique for this edge point linking problem. Each edge point is linked to its appropriate neighbor on either side by considering those contours, produced by thresholding, which pass through the given edge point. For each such contour, the edge point nearest the given edge point along the contour (in, say, the clockwise direction) is recorded. The edge point occurring most often as an associate across the set of gray level thresholds, is chosen as the clockwise associate. A figure of merit based on path length and straightness is used to break any ties. The counterclockwise neighbor is chosen similarly. Two points which are mutual associates denote a symmetric link. If all non-symmetric links are deleted, the resulting structure is a set of linear chains of nodes called 'symchains' It is claimed that symchains provide a rich edge structure for further processing.© (1980) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.