Elliptical Markers Research Articles

A Robust Real-Time Ellipse Detection Method for Robot Applications

Over the years, many ellipse detection algorithms have been studied broadly, while the critical problem of accurately and effectively detecting ellipses in the real-world using robots remains a challenge. In this paper, we proposed a valuable real-time robot-oriented detector and simple tracking algorithm for ellipses. This method uses low-cost RGB cameras for conversion into HSV space to obtain reddish regions of interest (RROIs) contours, effective arc selection and grouping strategies, and the candidate ellipses selection procedures that eliminate invalid edges and clustering functions. Extensive experiments are conducted to adjust and verify the method’s parameters for achieving the best performance. The method combined with a simple tracking algorithm executes only approximately 30 ms on a video frame in most cases. The results show that the proposed method had high-quality performance (precision, recall, F-Measure scores) and the least execution time compared with the existing nine most advanced methods on three public actual application datasets. Our method could detect elliptical markers in real-time in practical applications, detect ellipses adaptively under natural light, well detect severely blocked and specular reflection ellipses when the elliptical object was far from or close to the robot. The average detection frequency can meet the real-time requirements (>10 Hz).

KESALAHAN PENGGUNAAN KOHESI GRAMATIKAL DALAM PENULISAN FORTOFOLIO PESERTA TES POTENSI JABATAN ADMINISTRATOR DAN PENGAWAS DI LINGKUNGAN KABUPATEN BREBES TAHUN 2018

This study aims to describe and analyze errors in the use of grammatical cohesion in writing pesrta portfolios to test the potential positions of administrators and supervisors in the Brebes Regency in 2018. The research data are misuse of markers of grammatical cohesion. The data analyzed is the discourse text from the writing of the portfolio. Data is then analyzed by using the content analysis method. The results of the research obtained indicate that the most widely used pronouns of pronouns / pronouns in portfolios are me and we in arranging sentences and tend to be repeated. substitutions that are often used are subtitution replacing the word / sentence group. The use of elliptical markers of grammatical cohesion in the portfolio eliminates many groups of words, making many sentences ineffective, while the most widely used conjunctions are additive conjunctions and causal conjunctions. The conjunctions that are used by ASN in writing are still a lot of inappropriate and misplaced ones.

Quantification of Strain of the Pan-African in Mvog-Betsi Area (Yaoundé Group, Cameroon)

The ductile deformation in the paragneissic bed of Mvog-Betsi in the north-eastern part of Yaounde (Cameroon) appears to be intensive and may be traduced by a high shear rate (more than 10%). Some marker subjects that may quantify this strain are observed. Those are elliptical quartz and feldspar, and folds. The study of elliptical markers shows their preferential orientation. The initial rate R_i of the markers before the strain approaches 3.76, and the harmonic value of R_f is between 1.51 and 1.71. Main orientation Ø_f of strain’s ellipse from the direction of stretching in actual position is situated between -10 and -19. The strain’s rate R_S is comprised between 1.1 and 1.7. The orientation Ø_S of the strain’s ellipse is situated between N10E and N20E. The rate of shortening varies between 20% and 75%.

Finite strain estimation from deformed elliptical markers: The minimized [formula omitted] (MIRi) iterative method

A new technique for estimating the finite strain of deformed elliptical markers is presented. This method is based on the property of the arithmetic mean Rf¯ of the deformed object aspect ratios Rf to reach its minimum value in the undeformed state when they correspond to the initial aspect ratios Ri. The minimized Ri¯ (MIRi) iterative method furnishes the best results when, in the pre-strain state, the markers are uniformly orientated for every aspect ratio (Ri) class. A Matlab code, provided in this study, finds the best values of strain Rs and maximum stretching direction X that minimize the arithmetic mean Ri¯ by means of several iterations. In order to define the uncertainties of Rs and X, the code: (i) re-samples h-times the original (Ri, θ) dataset; (ii) assigns random values to the initial long axis angles θ; (iii) deforms newly the synthetic dataset; (iv) re-applies the MIRi method; and finally (v) estimates the standard deviation for the (Rs, X) values. Tests of the method on synthetic aggregates of elliptical markers and two naturally deformed rocks provide strain values that are compared with estimations from other available methods.

A Windows program for the analysis of tectonic strain using deformed elliptical markers

A Windows program for the analysis of tectonic strain using deformed elliptical markers

ELLIROT—A program to view and analyze spatial distributions of ellipses

Abstract The program ELLIROT (ELLIpse ROTation), written in TurboPascal for IBM-compatible microcomputers, uses computer graphics to examine the three-dimensional distribution of elliptical objects, if the data distribution can be represented by an ellipsoid. In strain analysis, the final strain ellipsoid can be determined with ELLIROT from elliptical markers with arbitrary orientations in space.

Automated two-dimensional strain analysis from deformed elliptical markers using an image analysis system. Microcomputer techniques and applications

Automated two-dimensional strain analysis from deformed elliptical markers using an image analysis system. Microcomputer techniques and applications

Automated two-dimensional strain analysis from deformed elliptical markers using an image analysis system

An image analysis system is used to automate data collection from deformed elliptical markers and calculate strain using computer programs. In the image analysis, best-fit ellipses are calculated for individual binarized markers, and their axial ratios and long-axis orientations are used for strain calculations. The precision of data obtained by our system is within ±11% for axial ratios and within ±3° for long-axis orientations when a marker has an area larger than 360 pixels in an image area of 512 × 480 pixels, and is located in the central part of 256 × 240 pixels. An example of strain analysis from 275 ooids in a deformed oolitic limestone shows that the strain ellipse calculated from the data obtained by image analysis has a ∼3% higher axial ratio and a 2.6° difference in long-axis orientation compared to manual methods. Finite strain analyses can be done automatically and precisely in a short time by using image analysis methods.

Application of the [formula omitted] technique to ellipitical markers deformed by pressure-solution

The applicability of the R f φ technique of finite strain analysis to elliptical markers whose shape is modified by pressure-solution is investigated. Variably oriented elliptical markers shortened by removing material from one or both sides in open and closed systems are compared to markers shortened homogeneously by the same amount. For the models examined, it was found that the R f φ technique correctly predicts the principal directions, the initial marker axial ratio, and the axial ratio of a circle deformed in a like manner. Interpretation of strain ratios in terms of percent shortening requires knowing how much volume was lost. Equations relating the strain ratio to percent shortening are given for both constant-volume and volume-loss deformation.

A new plot to display the strain of elliptical markers

A modification of the Elliott grid for plotting ellipse shape data are described. The effects of strain on elliptical markers are easy to visualize when the data are plotted on the new grid, and this allows clear interpretation of displayed data. New graphical methods for manipulating distributions of elliptical markers are directly related to an existing numerical method. When a distribution on the grid is strained, all the points move along straight, parallel lines. An initial distribution in which all the points lie on a straight line is strained into a distribution with the points lying on a hyperbola. Such curves include the analogues of ‘theta curves’. If the points lie on a circle centred at the grid origin, they are strained so as to lie on an ellipse. These are the analogues of ‘onion curves’.

Strain analysis of passive elliptical markers: success of de-straining methods

Where passive elliptical markers are homogeneously and coaxially strained the strain ellipse ratio may be estimated to within 10%. This takes account of inaccuracies in measurement and does not assume knowledge of the strain ellipse's orientation. Between 50 and 75 markers are needed to achieve this accuracy and larger sample sizes do not significantly improve on this. The de-straining methods use two different tests for randomness of the de-strained fabric. One of these, the runs test, is particularly sensitive to clustering in the angular distribution and may be of particular value in de-straining sedimentary fabrics. De-straining methods are warranted where the strain ellipse ratio is ⩾3.0 in natural data.

Calculation of finite incremental deformations in ductile geological materials and structural models

Although the total continuous deformation of rocks can be the net result of several tectonic pulses (finite increments), it will be assumed that there are only two. It is further assumed that differential displacements are unknown, but that two generations of rotation gauges are available in a rock body, together with two respective generations of strain gauges. A mathematical procedure is outlined herein for calculating the first or second deformation increment in natural structures and putty models with elliptical markers. To illustrate their practical value, one set of equations is used to determine the pattern of large incremental strain associated with the lateral spreading of a mature model diapir. This model pattern may help to interpret igneous fabric patterns of undeformed granitoid plutons.

Elliptical markers and non-coaxial strain increments reply

Elliptical markers and non-coaxial strain increments reply

Elliptical markers and non-coaxial strain increments — discussion

In a recent paper, Siddans (1980) attempts to show that the “unstraining R f / φ” technique gives an incorrect estimate of non-coaxial strain in a tectonically imbricated ellipse distribution. The model used in the demonstration is shown to be invalid.

Elliptical markers and non-coaxial strain increments

A succession of geologically observed, non-coaxial strain increments is applied homogeneously to two models: 1. (1) a suite of randomly oriented ellipses with constant axial ratio, 2. (2) a suite of ellipses with variable axial ratio and semi-planar long axis orientation. In the first model the final ellipses lie on an Rf/ φ curve that gives an estimate of the finite strain state that is correct in both axial ratio and orientation. In the deformed state the second model results in a tectonically imbricated shape fabric and it is shown that an attempt to estimate the finite strain by the “unstraining Rf/ φ” technique gives an incorrect axial ratio.

Tests of computerised strain analysis methods by the analysis of simulated deformation of natural unstrained sedimentary fabrics

Axial ratio—fluctuation measurements made on markers (oncolites, oolites, quartz grains, and accretionary lapilli) on bedding-perpendicular sections of unstrained sedimentary rocks have been homogeneously strained mathematically by set amounts, using published transformation equations, to provide a simulation of natural tectonic deformation. The resultant data have been used as test input to the strain analysis computer programs of Dunnet and Siddans (1971) and Matthews et al. (1974), which were devised to assess tectonic strain in assemblages of strained elliptical markers, with the use of limited specific assumptions concerning the nature of the pre-tectonic fabrics of the markers. The tests have shown that even slight deviations in the initial fabrics from the assumptions involved in the use of the strain analysis methods may lead to significant errors in the strain determinations. Errors are particularly large when fabrics which were imbricate in the unstrained state are used with the mistaken assumption that they were bedding-symmetric.

A FORTRAN IV program for the analysis of tectonic strain using deformed elliptical markers

A FORTRAN IV computer program is presented which provides an objective approach to tectonic-strain marker analysis. The algorithms are based on the “Theta-Curve” method and include a test (chi-square, goodness of fit) to check the validity of an initially random marker deformation model. Graphically represented values of confidence versus calculated tectonic-strain estimates, are produced for critical interpretation of results. Orientation data are not dependent on any preconceived reference directions such as cleavage or bedding. The method does assume, in its undeforming procedure, that the median value of the deformed marker-orientations is equivalent to the direction of maximum extension in the finite-strain ellipse. Optional line-printer graphics in separate subroutine form are included for producing the widely accepted R f Φ f diagrams and may be interfaced easily with other strain-analysis programs. A data-conversion program is appended to enable the use of preexisting data sets intended for the STRANE program of Dunnet and Siddans.

Clastic grain shape and orientation in relation to cleavage from the Aberystwyth Grits, Wales

Samples from a competent greywacke bed within the Aberystwyth Grits at Cwm Tydi, Cardiganshire, reveal a preferred dimensional orientation of clastic grains parallel or subparallel to the cleavage. Plots of grain axial ratio against orientation ( Rf Ø ) indicate that grain-shape changes have occurred as well as alignment of the long axes. These Rf Ø plots are compared with those predicted by a mechanism involving homogeneous strain superimposed on initially randomly-oriented elliptical markers. New Rf Ø reference curves facilitate a straightforward comparison of actual plots with the theoretically-predicted ones. The Rf Ø diagrams show consistently a broader scatter of Ø values than the homogeneous model predicts suggesting that other mechanisms have been operative during the deformation. Textural evidence under the microscope strongly supports a mechanism involving solution of grain contacts lying along distinct “channel-ways” parallel to the cleavage. A simple pressure solution model involving reduction of grain size is considered. The model produces a low degree of preferred orientation but substantial changes of axial ratio thus giving similar, though not identical, Rf Ø diagrams to those obtained from the rocks. The cleavage probably owes its existence less to the preferred orientation of the grains than to the preferred location of the grain contacts along the “channel-ways”.

An algebraic method of strain analysis using elliptical markers : 12F, 3T, 19R. tectonophysics, V24, N1–2, 1974, P31–67 Matthews P.E., Bond R.A., Van Den Berg J.J.

An algebraic method of strain analysis using elliptical markers : 12F, 3T, 19R. tectonophysics, V24, N1–2, 1974, P31–67 Matthews P.E., Bond R.A., Van Den Berg J.J.

An algebraic method of strain analysis using elliptical markers

A new method is described for finite strain analysis of naturally deformed sub-fabrics of elliptical markers assuming an homogeneous deformation on the scale of the sample. The method is numerical, and relies on derived equations which relate the axial ratios and orientations of elliptical markers to algebraic parameters of finite linear transformations. This treatment provides criteria for the identification in the deformed state of initial random and non-random but symmetric distributions of elliptical markers about the bedding-trace. For these types of deformed fabric, the method allows: 1. (1) numerical evaluation of the finite strain ratio for the plane of section 2. (2) statistical estimation of the error in this determination due to the sample-size of measured markers and the orientation of the section 3. (3) optimal evaluation of the strain ratio in cases where an initial random fabric is identified 4. (4) determination of the pre-tectonic axial ratios and orientations of the elliptical markers relative to the undeformed bedding-trace 5. (5) determination of pre-tectonic compactional strain imposed on a random depositional fabric; and 6. (6) theoretical investigation of the minimum number of measurements required by the method for any specified level of precision in strain determination in relation to various postulated initial distributions of axial ratios and orientations. Some practical applications of the method are described.