Drawing Algorithms Research Articles

Computer-aided inverse panorama on a conical projection surface

The aim of this study is to develop a practical method of direct mapping of an inverse conical panorama with computer aid. The panoramic image is a central projection onto a conical surface from the centres dispersed on a circular or straight path located outside the projection surface. The proposed method is a nonlinear projection in which the resulting image is treated as a sequence of stitched pictures of zero width taken from a moving view point. Geometric data and relations between the projected points are utilised to formulate algorithms for drawing of inverse panoramic images of straight lines, which further enables drawing of wire frame models of represented forms. Images are drawn as plots of a function in the Mathcad software. However, in order to make drawing more efficient and convenient, as well as for the practical applications of them, the algorithms can be implemented in any graphical package.

About the algorithm for construction of coordinated university timetables

The factual description of the task and an algorithm for drawing up a coordinated timetable of academic work of the faculty and students at the level of department (local timetable) is presented, as well as the procedure for integrating private schedules, i.e. the formation of a university-wide timetable. Coordination of the latter has not only spatio-temporal in nature, but also takes into account the preferences (interests) of agents (users and performers of works).

OPTIMIZATION OF COMPUTING PROCESS OF THE ONBOARD COMPUTING SYSTEMS

Relevance of scope of parallel calculations was realized for a long time at the solution of complex scientific and technical challenges, as in connection with low reliability and productivity of computers, and in connection with emergence of the multiprocessor systems and multinuclear processors. The technology of ensuring reliability and high efficiency on the basis of parallel calculations naturally became prevailing in the onboard computing systems (OCS). Now such systems find broad application in aircraft and space equipment, and also in land and water mobile objects. Efficiency of performance of objectives, safety, operational suitability and some other important qualities of mobile objects considerably are defined by ability of the onboard computing system to carry out the functions. Development of the onboard equipment is characterized by constant increase in number of the solved tasks and increase of their complexity, expansion of intellectual and adaptive opportunities. It inevitably leads to complication of BVS, its operating system and the special software. For the period of the solution of the majority of the tasks assigned to BVS rigid temporary restrictions are imposed. Performance of these of the requirement results in need of the organization of parallel computing processes. In this work set of mathematical models, formulations of the tasks and approaches to their decision allowing to construct the schedule of parallel computing process for realization of the information and connected tasks on the multiprocessor onboard computing systems is presented. Models of sets of the solved tasks in the form of the loaded count and in a yarusno-parallel form, the solution of tasks on purposes of the solved tasks to processors and algorithm of drawing up the schedule of parallel computing process are given.

Machine Learning is Line Drawing Algorithm

Machine Learning is Line Drawing Algorithm

Graph Drawing and Analysis Library and Its Domain-Specific Language for Graphs’ Layout Specifications

This paper presents a graph drawing and analysis library written in Java called GRAD and its domain-specific language for simplifying the process of laying out graphs. One of GRAD’s main goals is to provide completely automated ways of selecting and configuring a drawing algorithm, based either on the properties of a graph or on a user’s input conforming to the domain-specific language. In order to verify the quality of GRAD’s main features a user study was conducted. The participants were asked to grade diagrams visualized and laid out using different modeling tools, including one relying on GRAD, which received the best overall scores.

A standards-based approach for Auto-drawing single line diagram of multivendor smart distribution systems

This paper presents a technique for the auto-drawing of single line diagram (SLD) of multivendor distribution systems. SLDs are used in electric power system visualization, which is very important for the control and monitoring of distribution systems for fault location, identification, separation, and service restoration. The task of auto-drawing an SLD for distribution systems has been made complicated due to the introduction of distributed generations and multivendor distribution systems. This paper proposes an algorithm for auto-drawing SLD, based on a ternary tree and collision avoidance algorithm. In addition, a standards-based approach is suggested for incorporating different distribution system planned and run by different vendors. Initially, client converts the distribution system diagram to a standard model, which is then sent to the server. The server draws the SLD by using the auto-SLD drawing algorithm and sends it back to the client, which can be verified by the client.

Brain Tumor Boundary Segmentation of MR Imaging using Spatial Domain Image Processing

Extracting information for medical purposes from magnetic resonance imaging is critically important for diagnostic and treatment plans. In this paper, a simple algorithm for tumor segmentation of Magnetic resonance imaging (MRI) is introduced. The novelty incorporates, preserving fine details of the input image while detecting the boundary accurately. Tumor segmentation is carried out by set of pre processing steps followed by morphological operations. Rough contour of the tumor is localized to reduce the search space for the boundary. Line drawing algorithm in cooperated with pixel selection criteria is used to detect the accurate boundary. The algorithm is evaluated in terms of the performance and accuracy with radiologist labelled ground truth MRI scans. Simulation results show that the proposed algorithm provides better identification with above 95% of accuracy, for clearly distinguishable tumors in relation to conventional contour detection methods.

Bayesian estimation of incompletely observed diffusions

We present a general framework for Bayesian estimation of incompletely observed multivariate diffusion processes. Observations are assumed to be discrete in time, noisy and incomplete. We assume the drift and diffusion coefficient depend on an unknown parameter. A data-augmentation algorithm for drawing from the posterior distribution is presented which is based on simulating diffusion bridges conditional on a noisy incomplete observation at an intermediate time. The dynamics of such filtered bridges are derived and it is shown how these can be simulated using a generalised version of the guided proposals introduced in Schauer, Van der Meulen and Van Zanten (2017, Bernoulli 23(4A)).

Information tools for teaching the basics of programming in high school

The article focuses on the problem of finding methodological approaches to the use of information programming tools in the course of computer science high school. The definition of information tools for teaching as electronic means of storage, processing and transfer of educational information through computers is set out. The authors, based on the analysis of four existing training programs in computer science 5-9 classes, identified the topics for studying students of the middle classes of programming: "Algorithms and Programs", "Algorithms and their Implementers", "Algorithmization and Programming", "Fundamentals of algorithmization and programming". It is revealed that the computer science curriculum for grades 8-9 for general education institutions with in-depth study of individual subjects does not include any programming topics. The analysis of methodological recommendations on informatics teaching in 2016-2018 academic years allowed to determine the competency tasks that students should learn to solve when they study computer science in high school, for example, to develop and run a linear geometric figure drawing algorithm, to recreate the motion of a computer ' object on the plane, including the interception of obstacles, create a simple computer game using variables, analyze the results of the implementation of programs for processing values of numeric type, create a software project and more. The authors analyze the possibilities of such information learning tools as online gaming platforms, Internet resources, online programming learning environments, graphical programming environments, interactive learning environments, and application development environments. The methodical approaches to the use of informational learning tools in the course of computer science high school: the implementation of online online exercises to learn theoretical concepts, solving problems from the basics of algorithmization and programming in the online environment, teaching the stages of creating a program project through the study of online courses, the implementation of tasks for training programming in the online learning environment; learning in action with a graphical programming environment for robots; development of a software project in the programming environment.

INTERACTIVE LAND-USE OPTIMIZATION USING LAGUERRE VORONOI DIAGRAM WITH DYNAMIC GENERATING POINT ALLOCATION

Abstract. In this work, we devise an efficient method for the land-use optimization problem based on Laguerre Voronoi diagram. Previous Voronoi diagram-based methods are more efficient and more suitable for interactive design than discrete optimization-based method, but, in many cases, their outputs do not satisfy area constraints. To cope with the problem, we propose a force-directed graph drawing algorithm, which automatically allocates generating points of Voronoi diagram to appropriate positions. Then, we construct a Laguerre Voronoi diagram based on these generating points, use linear programs to adjust each cell, and reconstruct the diagram based on the adjustment. We adopt the proposed method to the practical case study of Chiang Mai University’s allocated land for a mixed-use complex. For this case study, compared to other Voronoi diagram-based method, we decrease the land allocation error by 62.557 %. Although our computation time is larger than the previous Voronoi-diagram-based method, it is still suitable for interactive design.

On RAC drawings of 1-planar graphs

A drawing of a graph is 1-planar if each edge is crossed at most once. A graph is 1-planar if it has a 1-planar drawing. A k-bend RAC (Right Angle Crossing) drawing of a graph is a polyline drawing where each edge has at most k bends and edges cross only at right angles. A graph is k-bend RAC if it has a k-bend RAC drawing. A 0-bend RAC graph (drawing) is also called a straight-line RAC graph (drawing). The relationships between 1-planar and k-bend RAC graphs have been partially studied in the literature. It is known that there are both 1-planar graphs that are not straight-line RAC and straight-line RAC graphs that are not 1-planar. The existence of 1-planar straight-line RAC drawings has been proven only for restricted families of 1-planar graphs. Two of the main questions still open are: (i) What is the complexity of deciding whether a graph has a drawing that is both 1-planar and straight-line RAC? (ii) Does every 1-planar graph have a drawing that is both 1-planar and 1-bend RAC? In this paper we answer these two questions. Namely, we prove an NP-hardness result for the first question, and we positively answer the second question by describing a drawing algorithm for 1-planar graphs.

Research on the Design of Smart Paint Robot

This paper design the smart robot system which can capture the characteristics of image using image processing and control algorithm with vc++programming. The system can obtain clear image contour through complex image processing of Edge Drawing (ED) algorithm with HALCON image processing software , and complete the portrait drawing with mechanical arm of three-axis motion control through the line interpolation algorithm and running speed control. Then the system control the amount of spraying pump dominated by shaft motor control card, stepper motors, drives and detection sensing device etc., so as to achieve clear and coherent sketch portrait painting effect. Test shows that the design of robot take no more than 10 minutes to paint a portrait, much faster than the street artists. It can be used for food prints and other wide commercial applications.

Identification and Red Blood Cell Automated Counting from Blood Smear Images using Computer Aided System

Objectives: Red blood cell count plays a vital role in identifying the overall health of the patient. Hospitals use the Haemocytometer to count the blood cells. Conventional method of placing the smear under microscope and counting the cells manually leads to erroneous results and medical laboratory technicians are put under stress. A computer aided system will help to attain precise results in less amount of time. It proposes an image processing technique for counting the number of Red blood cells. This aims to examine and process the blood smear image, in order to support the counting of red blood cells and identify the number of normal and abnormal cells in the image automatically. Methods/Statistical Analysis: K-Medoids algorithm which is robust to external noise is used to extract the WBCs from the image. Granulometric analysis is used to separate the Red blood cells from White blood cells. The Red blood cells obtained are counted using the Labeling algorithm and Circular Hough Transform. The radius range for the circle drawing algorithm is estimated by computing the distance of the pixels from the boundary which automates the entire algorithm. Findings: A comparison is done between the counts obtained using the Labelling algorithm and Circular Hough Transform. Results of the work showed that Circular Hough Transform was more accurate in counting the Red blood cells than the Labelling algorithm as it was successful in identifying even the overlapping cells. The work also intends to compare the results of cell count done using the proposed methodology and manual approach. The results showed that the proposed cell counting approach was much faster and accurate than the manual approach. The work is designed to address all the drawbacks of the previous research work. Novelty/Improvement: It can be extended to extract various texture and shape features of abnormal cells identified so that diseases like Anemia of inflammation and chronic disease can be detected at the earliest.

Topological Decomposition of Directed Graphs

The analysis of directed graphs is important in application areas like software engineering, bioinformatics, or project management. Distinguishing between topological structures such as cyclic and hierarchical subgraphs provides the analyst with important information. However, until now, graph drawing algorithms draw the complete directed graph either hierarchically or cyclic. Therefore, we introduced new algorithms for decomposing the input graph into cyclic subgraphs, directed acyclic subgraphs, and tree subgraphs. For all of these subgraphs, optimized layout algorithms exist. We developed and presented a new algorithm for drawing the complete graph based on the decomposition using and combining these layouts. In this paper, we focus on the algorithms for the topological decomposition. We describe them on an intermediate level complementing the previous descriptions on the high and the low level. Besides the motivation, illustrative examples of all cases that need to be considered by the algorithm, standard as well as more complex ones, are given. We complement this description by a complexity analysis of all algorithms.

Monotone drawings of graphs with few directions

A monotone drawing of a graph G is a straight-line planar drawing of G such that every pair of vertices is connected by a path that is monotone with respect to some direction. Thus, a path towards every possible destination vertex can be easily found in a monotone drawing by following a certain direction. However, since different pairs of vertices may use different directions of monotonicity, selecting the correct direction to follow may become as complicated as the original task of finding the path. To overcome this limitation, in this paper we study the existence of monotone drawings in which the number of different directions of monotonicity used by all the pairs of vertices is small.We show that a planar graph admits a monotone drawing with only one direction of monotonicity if and only if it has a Hamiltonian path between two vertices lying in the same face. Also, we prove that maximal planar graphs admit monotone drawings with two (orthogonal) directions, while triconnected planar graphs with three directions. The latter two results are obtained by applying the famous drawing algorithm based on Schnyder realizers.

Coherent structure colouring: identification of coherent structures from sparse data using graph theory

We present a frame-invariant method for detecting coherent structures from Lagrangian flow trajectories that can be sparse in number, as is the case in many fluid mechanics applications of practical interest. The method, based on principles used in graph colouring and spectral graph drawing algorithms, examines a measure of the kinematic dissimilarity of all pairs of fluid trajectories, measured either experimentally, e.g. using particle tracking velocimetry, or numerically, by advecting fluid particles in the Eulerian velocity field. Coherence is assigned to groups of particles whose kinematics remain similar throughout the time interval for which trajectory data are available, regardless of their physical proximity to one another. Through the use of several analytical and experimental validation cases, this algorithm is shown to robustly detect coherent structures using significantly less flow data than are required by existing spectral graph theory methods.

TikZ-Feynman: Feynman diagrams with TikZ

TikZ-Feynman is a LaTeX package allowing Feynman diagrams to be easily generated within LaTeX with minimal user instructions and without the need of external programs. It builds upon the TikZ package and leverages the graph placement algorithms from TikZ in order to automate the placement of many vertices. TikZ-Feynman still allows fine-tuned placement of vertices so that even complex diagrams can be generated with ease. Program summaryProgram title: TikZ-FeynmanCatalogue identifier: AFBF_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFBF_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: GNU GPL v3No. of lines in distributed program, including test data, etc.: 6727No. of bytes in distributed program, including test data, etc.: 413779Distribution format: tar.gzProgramming language: TeX, LaTeX, Lua.Computer: PC’s or workstations.Operating system: Any capable of processing LaTeX.Classification: 4.4.External routines: TikZNature of problem:Existing methods for drawing Feynman diagrams in LaTeX usually require external programs and are not very user friendly thereby making it difficult and time consuming to generate even simple diagrams.Solution method:TikZ-Feynman provides an easier way to draw Feynman diagrams by building on TikZ and using graph drawing algorithms to automatically place vertices. This can be combined with some positioning to produce complicated diagrams with relative ease.Running time:Depends on the size

Sensor Positioning on Digital Maps for Coverage Maximization by Using Genetic Algorithm

In the areas of surveillance and mobile communications, computer-aided evaluation of coverage area and measure of the field of sensors positioned on a created digital elevation model (DEM) is a facilitating method for positioning sensors and communication equipment. Fast evaluation of sensor coverage enables a computer to discover appropriate sensor locations by testing miscellaneous locations. In this paper, we describe a coverage maximization method that uses genetic algorithm and drawing algorithms based on integer arithmetic for coverage evaluation. Furthermore, solution of a sample problem and performance data gathered during solving process are presented, and the method's ability of finding good positions of radars for sea surveillance on a single processor PC in a duration less than ten minutes demonstrated.

Simultaneous visibility representations of plane st-graphs using L-shapes

Let 〈Gr,Gb〉 be a pair of plane st-graphs with the same vertex set V. A simultaneous visibility representation with L-shapes of 〈Gr,Gb〉 is a pair of bar visibility representations 〈Γr,Γb〉 such that, for every vertex v∈V, Γr(v) and Γb(v) are a horizontal and a vertical segment, respectively, which share an end-point. In other words, every vertex is drawn as an L-shape, every edge of Gr is a vertical visibility segment, and every edge of Gb is a horizontal visibility segment. Also, no two L-shapes intersect each other. An L-shape has four possible rotations, and we assume that each vertex is given a rotation for its L-shape as part of the input. Our main results are: (i) a characterization of those pairs of plane st-graphs admitting such a representation, (ii) a quadratic time algorithm to recognize them, and (iii) a linear time drawing algorithm if the test is positive. As an application, starting from a simultaneous visibility representation with L-shapes, we show how to compute a simultaneous embedding of the two graphs with at most two bends per edge and right-angle crossings.

HYBRID-BASED DENSE STEREO MATCHING

Abstract. Stereo matching generating accurate and dense disparity maps is an indispensable technique for 3D exploitation of imagery in the fields of Computer vision and Photogrammetry. Although numerous solutions and advances have been proposed in the literature, occlusions, disparity discontinuities, sparse texture, image distortion, and illumination changes still lead to problematic issues and await better treatment. In this paper, a hybrid-based method based on semi-global matching is presented to tackle the challenges on dense stereo matching. To ease the sensitiveness of SGM cost aggregation towards penalty parameters, a formal way to provide proper penalty estimates is proposed. To this end, the study manipulates a shape-adaptive cross-based matching with an edge constraint to generate an initial disparity map for penalty estimation. Image edges, indicating the potential locations of occlusions as well as disparity discontinuities, are approved by the edge drawing algorithm to ensure the local support regions not to cover significant disparity changes. Besides, an additional penalty parameter 𝑃𝑒 is imposed onto the energy function of SGM cost aggregation to specifically handle edge pixels. Furthermore, the final disparities of edge pixels are found by weighting both values derived from the SGM cost aggregation and the U-SURF matching, providing more reliable estimates at disparity discontinuity areas. Evaluations on Middlebury stereo benchmarks demonstrate satisfactory performance and reveal the potency of the hybrid-based dense stereo matching method.