An effective method to detect straight lines from high spatial resolution remotely sensed imagery and its applications for runway extraction

This paper proposes a lane detection method based on the constraint Hough Transform double edge extraction. Firstly, the image of the road is grayed out and dealt with the lane line area extraction process based on the lane width feature and color feature. For grayscale images, the Canny edge detection operator is used to obtain the lane line edge information. Then the lane line features are extracted through the lane line edge information and the lane line area information. For the straight lane line, the Hough transform based on the polar angle and polar radius constraints is used to obtain the double edges of the lane lines, and straight line points are used to determine the end points and starting points of the straight lane lines to complete the straight line fitting. For the curve, the near-field part is a straight line, the far-field is a curve, and the straight part adopts the detection method of the straight lane line, and the characteristic points of the curve are searched in the lane line characteristic diagram. Finally, the curve is fitted by a parabola. Experiments show that the lane detection using the double-edge extraction method is fast and accurate.

This paper presents the results of a study undertaken to enhance the stability of a landfill on sloping ground of a hilly region. The base of the landfill has a significant elevation difference from one end to the other causing an overall inclination of the base with the horizontal. The study highlights the influence of the following factors on the base sliding stability along the geomembrane interface as: (a) leachate head; (b) pore water pressures in wet waste; (c) seismic forces and (d) smooth versus textured geomembrane (GM). Limit equilibrium methodology is adopted for analyses and three types of failure surfaces are analysed – circular, planar (single straight line) and planar (two straight lines). The study reveals that stability against sliding along liner is low, whenever (a) pore pressures/leachate head are high; (b) earthquake forces are large and (c) smooth GM are used. Usually planar failure surface (two straight lines) is observed as the critical surface.Furthermore, it is also observed that the stability of the sloping liner can be enhanced significantly by providing adequate size of earthen berm at the toe. After application of the berm at the toe, the possible critical failure surface may pass over the back slope of the berm or pass under the bottom of the berm. This depends on the geometric dimensions (height & base-width/back slope) of the berm. Planar failure surfaces (two and three straight lines) are analysed to check the stability. The study reveals that by varying the berm height as well as the base width, one can arrive at an optimal solution for stability.KeywordsLandfillsStability enhancementSloping groundEarthen berms

Straight line is an important intermediate symbol, and the straight line extraction is one of the key technologies in image processing and computer vision. Aiming to the characteristics of digital image spatial domain, a straight line model of image spatial domain is established, and a heuristic algorithm based on the model for straight line extraction is presented, Which gets the edge amplitude image by edge detecting, and extracts the straight line which matches the straight line model through employing heuristic search guided by the edge information. The simulation shows that the algorithm is robust for image noise, and it not only can extract the low contrast straight line, but also can eliminate the short fractured straight line effectively.

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As discussed by Gunther & Blinn (1955), there appear to be two principal types of residues on and in treated plant parts. When log residue or percentage of loss or retention of residue is plotted against days after application, a single straight line is obtained with most substrates. With citrus peel as the substrate, however, two intersecting straight lines are usually obtained. The single line represents the summation of degradation3 and persistence behavior, whereas the initial straight line of an intersecting pair is considered to represent degradation, and the line of subsequent behavior to represent the persistence phenomenon. Obviously, the two types of behavior overlap with citrus peel, but it is convenient for purposes of discussion to consider that degradation curves demonstrate graphically the sum of the processes usually classified as weathering, and that falling persistence curves undoubtedly demonstrate enzymatic or other alterations of the parent molecule within the plant part (Gunther & Blinn 1955).

Definitions and basic concepts

In elementary books (like this one) the development of hyperbolic geometry is often based on a stronger version of ~ Playfair’s Postulate: Postulate H. If P is any point and AB is any straight lines YPZ and WPX such that (1) YPX is not a single straight line, (2) YPZ and WPX are each parallel to AB, and (3) no straight line through P entering LYPX is parallel to AB. (See figure 146). KeywordsAcute AngleEuclidean GeometryHyperbolic GeometrySmall TriangleEqual AngleThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Projective transformations of a standard coordinate system can be written in the form: u=c3+(e1x+e2y)/(c7x+c8y+1),υ=c3+(e4x+e5y)/(c7x+c8y+1).The shapes and relative sizes of all geometrical figures subjected to such transformations will be invariant if the values of c7, and c8 are invariant, and if the following quantities are also invariant: (e1e5−e2e4)/(e1e2+e4e5),(e22+e52)/(e12+e42).The sizes of such figures are invariant when the numerators and denominators of these expressions are themselves invariant.Colors having equally noticeable differences can be represented by equidistant points in some projective transformation of the standard color-mixture diagram only if in the standard diagram the separations of the points on any line representing a series of equally noticeably different colors are proportional to the square of the distance from some unique point on that line, and if the locus of such unique points for all linear series of colors is a straight line. The locus of colors equally noticeably different from any standard color can be represented adequately in the standard color-mixture diagram by an ellipse. All such ellipses can be transformed by a single projective transformation into equal-sized circles only if the common tangents of every pair of ellipses intersect on a single straight line. This line is the same as the locus of unique points for the series of colors just described. The equation of this straight line is (c7x+c8y+1 = 0), where the constants are those appearing in the denominators of the successful transformation formulas. If the separations of points representing equally noticeably different colors in the standard color-mixture diagram cannot be represented adequately in the manners described, then such colors cannot be represented adequately by equidistant points in any projective transformation of the standard coordinate system.

Stabilities and 1H NMR studies of (diethylenetriamine)Pd(II) and (1,1,4,7,7-pentamethyldien)Pd(II) with nucleosides and related ligands

For railway signalling and control tasks, Takagi's synchronization control approach [1] can be used to shorten the headway between adjacent trains which operate under the moving block signalling system. However, such a control approach assumes that each train runs on a single straight track line and therefore cannot be used directly to the existing railway configurations which in practice have turning and crossing points. This paper proposes a solution to this practical implementation issue by combining a measurement-based map conversion algorithm to Takagi's synchronization control scheme. The proposed algorithm essentially converts a two-dimensional measurement data set from a GPS into a single straight track line position as required by the train detection system in Takagi's synchronization control approach. Experimental results from the implementation of the proposed approach are presented.

Extensions of counterion condensation theory. I. Alternative geometries and finite salt concentration

This paper presents a registration method which based on straight lines primitive. Firstly, 2D straight lines are extracted from aerial images using Canny operator and straight line fitting. In the similar way, 3D straight lines are extracted from LiDAR range images which derive from laser scanning point cloud. Secondly, 3D straight lines are projected to aerial images using collinearity equations and Position and Orientation System (POS) data. Then the corresponding lines are determined by straight line error. At last, each image's new exterior orientation elements are calculated by generalized point (straight line) photogrammetry.

Hydrologists use double-mass analysis to verify the consistency of a precipitation or streamflow record. Precipitation of a station is plotted against the combined precipitation of the surrounding stations. The consistency of the record is verified if a single straight line fitted through the points is reasonable. The analysis is done on the computer by fitting a straight line and a fourth-degree polynomial through the points and comparing the two sums of squares of deviations of the points from the fitted curves. If a record is found to be inconsistent, it is adjusted by bringing the deviated points along a desired single straight line. The method should be of value to the hydrologists having access to computers.

To compare three methods of cervical length measurements using ultrasound in the first trimester: single-line, two-line, and tracing. Images appropriate for cervical length measurements were obtained using transvaginal ultrasound between 11 + 0 and 13 + 6 weeks' gestation. The cervix was measured on stored images using three methods: a single straight line, two segments (two-line method), and by tracing the distance along the cervical canal. Results were compared for intraoperator repeatability and interoperator variability. The degree of the cervical curvature was measured. The mean cervical measurement using the single-line measurement was 32.8 (SD 4.4) mm. The mean cervical length was essentially the same using the two-line and tracing measurement: 34.4 (SD 4.7) mm and 34.5 (SD 4.7) mm, respectively. Both intra- and interoperator agreement was high. The degree of curvature of the cervical canal was variable, with a resultant variability in the difference between the single straight line measurement and the other two types of measurement. Using stored images, each of the measurement techniques is highly reproducible. Both the two-line and the tracing methods yield larger measurements than the single-line technique. Therefore, it appears that in select cases the straight line measurement significantly underestimates the actual cervical length.

We present a new lossy technique for document image compression by using straight line extraction and a block context model. Straight line segments are extracted from a binary document image and subtracted from the original image. Their endpoint coordinates and width can then be efficiently coded. The remaining part of the image, which mainly contains text and other symbols, is coded using a high-order block context model (HOBCM) based on vector quantization (VQ). The proposed method is particularly effective for document images containing a large number of straight line segments, such as engineering or architectural drawings. It achieves much higher compression than conventional lossless techniques, such as the JBIG and CCITT G3 and G4 standards, with little loss of visual quality. In the experiments we carried out, a group of engineering drawings digitized at 200 dpi, compression ratios ranging from 30 to 70 were obtained.