Showing papers on "Line segment published in 2002"

Phase shifter tunable via apertures in the ground plane of the wave guide

Abstract: A phase shifting element adapted to introduce a variable phase shift to an electromagnetic wave includes a transmission line segment (10), such as amicrostrip line segment (1) or a segment of a waveguide, above a ground plane (or waveguide wall) (2). The ground plane or wall (2) includes at least one aperture (3) positioned below the microstrip line or waveguide segment (1). An electrically conductive tuning plate (4) is provided adjacent the ground plane or wall (2) and is movable, toward or away from the ground plane or wall. Movement of the tuning plate (4) provides adjustement of the phase shift introduced to an electromagnetic wave propagated through the waveguide segment.

Measurement of dimensions of solid objects from two-dimensional image(s)

Abstract: The present invention facilitates solid object reconstruction from a two-dimensional image. If an object is of known and regular shape, information about the object can be extracted from at least one view by utilizing appropriate constraints and measuring a distance between a camera and the object and/or by estimating a scale factor between a camera image and a real world image. The same device can perform both the image capture and the distance measurement or the scaling factor estimation. The following processes can be performed for object identification: parameter estimation; image enhancement; detection of line segments; aggregation of short line segments into segments; detection of proximity clusters of segments; estimation of a convex hull of at least one cluster; derivation of an object outline from the convex hull; combination of the object outline, shape constraints, and distance value.

The line segment match method for extracting road network from high-resolution satellite images

Abstract: This paper presents an approach, with emphasis on the newly proposed line segment matching method, for extracting urban road networks from high-resolution satellite images. The approach is based on the characteristics of the images, knowledge about road networks, and the related mathematical models. The approach is applied to several images of urban areas and is proved to be effective in both visual effect and positional accuracy.

Consistent line clusters for building recognition in CBIR

Abstract: This paper introduces a new mid-level feature, the consistent line cluster for use in content-based image retrieval. The color, orientation, and spatial features of line segments are exploited to group them into line clusters. The interrelationships among different clusters and the intra relationships within single clusters are used to recognize and roughly locate buildings in photographic images. Experiments are performed on a database of color images of outdoor scenes.

Waveform drawing system and method

Abstract: A waveform drawing routine is disclosed that includes receiving an array of predecessor image data points, wherein the predecessor image data points form a predecessor line that has a predecessor high end point and a predecessor low end point, receiving an array of successor image data points, wherein the successor image data points form a successor line having a successor high end point and a successor low end point, comparing the successor line to the predecessor line, and maintaining any portions of the predecessor line on a display that intersect with the successor line. The method described above for drawing each line segment that forms the waveform is repeated until a complete waveform is drawn on the display that consists of the concatenation of these individual lines.

Optical proximity correction for phase shifting photolithographic masks

Abstract: A method for producing a computer readable definition of photolithographic mask used to define a target pattern is provided. The phase shift mask patterns include phase shift windows, and the trim mask patterns include trim shapes, which have boundaries defined by such sets of line segments. For a particular pair of phase shift windows used to define a target feature in a target pattern, each of the phase shift windows in the pair can be considered to have a boundary that includes at least one line segment that abuts the target feature. Likewise, a complementary trim shape used in definition of the target feature, for example by including a transmissive region used to clear an unwanted phase transition between the particular pair of phase shift windows, includes at least one line segment that can be considered to abut the target feature. Proximity correction is provided by adjusting the position of the at least one line segment on the boundary of a phase shift windows in said pair which abuts the target feature, and by adjusting the position of the at least one line segment on the boundary of the complementary trim shape which abuts the target feature.

Digital image edge detection and road network tracking method and system

Abstract: A system and method for finding edge orientation and magnitude, and extracting a road path from an image. An image (4) is segmented into at least a first window and a second window. A first road segment having plural parameters within the first window is specified. Plural road segments are identified (6), each having plural parameters, in the second window. The orientation of plural line segments in the second window are determined (6), and paired (6), based on their orientation. The line segment orientations are determined by receiving a plurality of edge orientation estimates (8), transforming a portion of them (6), and aggregating the transformed portion (6) into an edge orientation estimate. A stochastic process is performed (6) on the plural parameters of the plural road segments to identify a second road segment having the maximum correlation with the plural parameters of the first road segment.

Kinetic medians and kd-trees

Abstract: We propose algorithms for maintaining two variants of kd-trees of a set of moving points in the plane. A pseudo kd-tree allows the number of points stored in the two children to differ by a constant factor. An overlapping kd-tree allows the bounding boxes of two children to overlap. We show that both of them support range search operations in O(n 1/2+ ∈) time, where ∈ only depends on the approximation precision. As the points move, we use event-based kinetic data structures to update the tree when necessary. Both trees undergo only a quadratic number of events, which is optimal, and the update cost for each event is only polylogarithmic. To maintain the pseudo kd-tree, we develop algorithms for computing an approximate median level of a line arrangement, which itself is of great interest. We show that the computation of the approximate median level of a set of lines or line segments can be done in an online fashion smoothly, i.e., there are no expensive updates for any events. For practical consideration, we study the case in which there are speed-limit restrictions or smooth trajectory requirements. The maintenance of the pseudo kd-tree, as a consequence of the approximate median algorithm, can also adapt to those restrictions.

Kinetic maintenance of context-sensitive hierarchical representations for disjoint simple polygons

Abstract: We describe how to construct and kinetically maintain a tessellation of the free space between a collection of k disjoint simple polygonal objects with a total of N vertices, R of which are reflex. Our linear size tessellation consists of pseudo-triangles and has the following properties: (i) it contains disjoint outer hierarchical representations of all objects where the size of the outer boundary of these representations is proportional to a minimum link separator for the objects, and (ii) any line segment in the free space intersects at most O((k + log R) log N) pseudo-triangles (each of constant size).We maintain our tessellation by using the Kinetic Data Structure (KDS) framework. Our structure is compact, maintaining an active set of certificates whose number is linear in the size of a minimum link subdivision for the objects. It is also responsive; on the failure of a certificate invariants can be restored in time logarithmic in the total number of vertices. While its efficiency is difficult to establish precisely, it is shown that at most O(k + κmaxlog R)log N events happen during straight line motion of one object A in the context of k (fixed) others, where κmax denotes the maximum size of the minimum link polygon separating object A from the rest, during the motion.Furthermore, ray shooting queries (that use point location) can be answered in O((k + log R) log N) time for rays with arbitrary direction.

Line segment crack recovery from incomplete boundary data

Abstract: We are concerned with non-destructive control issues, namely detection and recovery of cracks in a planar (2D) isotropic conductor from partial boundary measurements of a solution to the Laplace–Neumann problem. We first build an extension of that solution to the whole boundary, using constructive approximation techniques in classes of analytic and meromorphic functions, and then use localization algorithms based on boundary computations of the reciprocity gap.

Information processing method and apparatus

Abstract: An input coordinate sequence is acquired by sampling a handwritten input pattern at predetermined intervals, and a pattern expressed by this input coordinate sequence is approximated by coupling a plurality of line segments to attain line segment conversion. Adjacent angle data φ[i] is generated based on the directions of the respective line segments. At this time, the segment line length along line segments of all the line segments is divided by a predetermined value at equal intervals, and the angles obtained from the directions of the line segments at respective division positions are defined as φ[i]. This φ[i] is compared with a standard pattern (adjacent angle distribution data) prepared in advance to obtain a matching level. In this way, more accurate pattern matching for a handwritten input, which is approximately invariant to affine transformation and can reduce the influence of discretization errors can be implemented.

Segment-Based Map Building Using Enhanced Adaptive Fuzzy Clustering Algorithm for Mobile Robot Applications

Abstract: In this paper, we present a technique for on-line segment-based map building in an unknown indoor environment from sonar sensor observations. The world model is represented with two-dimensional line segments. The information obtained by the ultrasonic sensors is updated instantaneously while the mobile robot is moving through the workspace. An Enhanced Adaptive Fuzzy Clustering Algorithm (EAFC) along with Noise Clustering (NC) is proposed to extract and classify the line segments in order to construct a complete map for an unknown environment. Furthermore, to alleviate the problem of extensive computation associated with the process of map building, the workplace of the mobile robot is divided into square cells. A compatible line segment merging technique is then suggested to combine the similar segments after the extraction of the line segment by EAFC along with NC algorithm. The performance of the algorithm is demonstrated by experimental results on a Pioneer II mobile robot.

A Combined 3D Linear and Circular Interpolation Technique for Multi-Axis CNC Machining

Abstract: In multi-axis CNC machining of sculptured surfaces, a linear interpolation technique has been used to generate the command signals for positions along the straight line segments that connect each consecutive data point. Due to the rotational movements superimposed on the translational movements in multi-axis CNC machining, the actual cutter contact (CC) point moves along a space curve path, while the linear interpolation technique generates positions along the straight line path. The nonlinear curve segments deviate from the linearly interpolated line segments resulting in nonlinearity errors, which in turn, commonly cause difficulties to ensure high precision machining. An interpolator design technique for solving the nonlinearity errors problem in multi-axis CNC machining is presented. A combined 3D linear and circular interpolation principle is developed on the basis of the 3D linear and circular interpolation principles. The new designed interpolator is capable of driving the rotation movement pivot along a predesigned 3D curve path, so that the CC point motion trajectory is via a straight line connecting machining data points. Therefore, the proposed interpolator design technique on-line eliminates nonlinearity errors, and provides a solution to the nonlinearity errors problem for multi-axis CNC machining.

A priori degeneracy of one-dimensional rotation sets for periodic point free torus maps

Abstract: Diffeomorphisms of the two torus that are isotopic to the identity have rotation sets that are convex compact subsets of the plane. We show that certain line segments (including all rationally sloped segments with no rational points) cannot be realized as a rotation set.

Cache Oblivious Distribution Sweeping

Abstract: We adapt the distribution sweeping method to the cache oblivious model. Distribution sweeping is the name used for a general approach for divide-and-conquer algorithms where the combination of solved subproblems can be viewed as a merging process of streams. We demonstrate by a series of algorithms for specific problems the feasibility of the method in a cache oblivious setting. The problems all come from computational geometry, and are: orthogonal line segment intersection reporting, the all nearest neighbors problem, the 3D maxima problem, computing the measure of a set of axis-parallel rectangles, computing the visibility of a set of line segments from a point, batched orthogonal range queries, and reporting pairwise intersections of axis-parallel rectangles. Our basic building block is a simplified version of the cache oblivious sorting algorithm Funnelsort of Frigo et al., which is of independent interest. Full text: http://dx.doi.org/10.1007/3-540-45465-9_37

Linear Facility Location in Three Dimensions---Models and Solution Methods

Abstract: We consider the problem of locating a line or a line segment in three-dimensional space, such that the sum of distances from the facility represented by the line (segment) to a given set of points is minimized. An example is planning the drilling of a mine shaft, with access to ore deposits through horizontal tunnels connecting the deposits and the shaft. Various models of the problem are developed and analyzed, and efficient solution methods are given.

Image processing apparatus and method therefor

Abstract: Provided is an image processing apparatus and a method for realizing a method for detecting an obstacle at high speed and stably by using one TV camera and paying attention to a difference in distribution of motion parallax between a road surface and an obstacle An image input unit captures a time-series image The candidate area tracking unit 1 extracts a line segment having a specific direction, sets an obstacle candidate area around the line segment, and searches for the area around the line segment extracted every frame, thereby quickly identifying the obstacle candidate area Chase The plane assumption verification unit 3 determines to which of a plurality of preset planes the candidate areas belong, using the tracking result of the set of candidate areas in which three or more candidate areas constitute one set The obstacle detection unit 4 detects an obstacle and estimates its position based on the result of the plane assumption verification unit 3 [Selection diagram] Fig 1

Attention to local form information can prevent access to semantic information.

Abstract: Humphreys and Boucart (1997) have shown that when processing of local form is required for response, surrounding global information is automatically processed to a semantic level. The generality of this effect was investigated in two experiments in which the perceptual load of the relevant local form information was manipulated, as was uncertainty about perceptual load. Participants attended to a single line segment inside a picture of an animal or a vehicle and then decided which of two pictures in the target/distractor display that followed contained a line segment that matched the first in orientation. The perceptual load of the relevant local form information was either low (the matching line segment was one of the solitary line segments presented in the centre of the target and distractor pictures), or high (the matching line segment was part of one of the solitary letters presented in the centre of the target and distractor pictures). The semantic relations among the pictures were manipulated, and w...

A probabilistic approach to roof extraction and reconstruction

Abstract: This paper investigates into the model-based reconstruction of complex polyhedral building roofs. A set of 3D line segments, obtained from multiview correspondence analysis of high resolution colour imagery, is used as input data. The 3D line segments are grouped into planes by means of a Bayesian model selection procedure. In the resulting planes, models for polygonal patches are then instantiated. Driven by the Maximum Expected Utility principle, the algorithm chooses the optimal patch and plane configuration non-deterministically. Roof reconstruction is completed by further reasoning steps which are guided by the semantic interpretation of the intermediate patch configuration. Several successfully reconstructed complex roof structures corroborate the potential of the approach.

A Comparative Study of Point Processes for Line Network Extraction in Remote Sensing

Abstract: We present in this report a comparative study between models of line network extraction, within a stochastic geometry framework We rely on the theory of marked point processes specified by a density with respect to the uniform Poisson process We aim to determine which prior density is the most relevant for road network detection The "Candy" model, introduced in [21] for the extraction of road networks, is used as a reference model This model is based on the idea that a road network can be thought of as a realization of a Markov object process, where the objects correspond to interacting line segments We have developed two variants of this model which use quality coefficients for interactions The first of these two variants is a generalization of the "Candy" model and the second one is an adaptation of the "IDQ" model proposed in [13] for the problem of building extraction from digital elevation models The optimization is achieved by a simulated annealing with a RJMCMC algorithm The experimental results, obtained for each model on aerial or satellite images, show the interest of adding quality coefficients for interactions in the prior density

Processing calibration-grid images using the Hough transformation

Abstract: When the angular displacement method is used in stereoscopic particle image velocimetry, a projection algorithm is required to map the image coordinates onto physical coordinates One difficulty is to find an accurate mapping function which describes the projection A new approach for determining a mapping function from calibration-grid images is presented The image of a Cartesian grid is processed using a windowing technique The image plane is covered by small overlapping windows The Hough transformation is used to detect straight line segments in each window The straight line segments correspond locally to the possibly curved grid lines in the image Then the data of these line segments are used to compute the coefficients of the mapping function The algorithm is robust and requires only a little interactive control Thus, an almost automatic evaluation of the calibration-grid images is possible

A local approach for fast line detection

Abstract: In this paper we are concerned with line detection for scene modelling. So we focus on horizontal and vertical lines and we propose a fast local approach to detect lines in binary images. The approach described here can easily be extended to lines characterized by other directions. Pixels are analysed using an accumulator on a block-based basis in order to obtain possible line segments for each block. As the results obtained rely only on a local analysis, their coherence can be further improved using a postprocessing step. The proposed method has been compared to classical approaches in order to show its efficiency.

Display method, display device, and display system

Abstract: PROBLEM TO BE SOLVED: To provide a display technique permitting a display securing suitable visibility in a display panel having a curved surface SOLUTION: In the display panel 21 having a curved surface, a display are is divided into seven areas 211-217 Then, picture correction is performed using a relation between a line segment La connecting both ends 211a, 211b of the area 211 and a line segment Lb in the vertical direction to a visual line SL extending from the end point 211b Here, the length of the line segment Lb is expressed by d and an angle between the both line segments La, Lb is expressed by θ, then, the length of the line segment La is d/cosθ By using the fact that the ratio R of both line segments La, Lb is R=1/cosθ, a picture correction data is produced by transforming a scale with respect to the fundamental picture data premised on a flat plane Moreover, concerning the other areas 212-217, a similar scale transformation is carried out to produce picture correction data Display is enabled while securing suitable visibility by displaying these picture correction data on the display panel 21

Application of Mathematical Morphology and Markov Random Field Theory to the Automatic Extraction of Linear Features in Airborne Images

Abstract: In this paper we present a model-based approach to the automatic extraction of linear features, like roads and paths, from aerial optical images. The proposed method consists of two steps. The first step utilizes local information related to the geometry and radiometry of the structures to be extracted. It consists of a series of morphological filtering stages. The resulting image (response) serves as input to a line-following algorithm, which produces a set of line segments. In the second step, a segment linking process is carried out incorporating contextual, a priori knowledge about the road shape, with the use of Markov random field (MRF) theory. In this approach the extracted line segments, produced by the morphological operators, are organized as a graph. The linking of these segments is then achieved through assigning labels to the nodes of the graph, using domain knowledge, extracted line segments measurements and spatial relationships between the various line segments. The interpretation labels are modeled as a MRF on the corresponding graph and the linear feature identification problem is formulated as a maximum a posteriori (MAP) estimation rule. The proposed approach has been successfully applied to airborne images of different profile