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Papers by Leonid Mestetskiy

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, May 12, 2023

The paper considers the problem of identifying game events in a video game of beach volleyball. A... more The paper considers the problem of identifying game events in a video game of beach volleyball. As a method for solving the problem, a combined approach is proposed based on recognizing the trajectory of the ball and constructing skeletal representations of the players. Temporal localization of game events is carried out by searching for the changes in the ball trajectory using the construction of a composite Bezier curve. Spatial localization is performed by the positioning of the ball and the players in the frame at the moment of the trajectory change. The classification is based on the skeletal representation of the player touching the ball. The experiments performed show that the algorithm is able to perform spatiotemporal localization with high precision and recall.

Экология. Экономика. Информатика, 2022

Communications in computer and information science, 2019

This book constitutes thoroughly revised and selected papers from the 10th International Joint Co... more This book constitutes thoroughly revised and selected papers from the 10th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications, VISIGRAPP 2015, held in Berlin, Germany, in March 2015. VISIGRAPP comprises GRAPP, International Conference on Computer Graphics Theory and Applications; IVAPP, International Conference on Information Visualization Theory and Applications; and VISAPP, International Conference on Computer Vision Theory and Applications. The 23 thoroughly revised and extended papers presented in this volume were carefully reviewed and selected from 529 submissions. The book also contains one invited talk in full-paper length. The regular papers were organized in topical sections named: computer graphics theory and applications; information visualization theory and applications; and computer vision theory and applications.

International Conference on Pattern Recognition, 2007

International Conference on Computer Vision, 2011

Some original and novel morphological concepts and tools are presented in this chapter as well as... more Some original and novel morphological concepts and tools are presented in this chapter as well as required amount of mathematical morphological basics. The continuous binary morphology based on a computational geometry is presented as a very fast approach to shape representation via real-time computation of figures’ skeletons. A skeletal representation of the figure is formed as a skeleton graph, and the radial function is determined in skeleton points. The proposed morphological spectrum is the multi-scale morphological shape description and analysis tools based on granulometry. It is shown how the tasks of change detection and shape matching in images can be solved using a morphological image analysis. The projective morphology as a generalized framework based on the mathematical morphology and the morphological image analysis provides fast and efficient solutions of morphological segmentation problem in complex images.

A new method of curve-skeleton extraction is proposed in this paper. Unlike most methods this app... more A new method of curve-skeleton extraction is proposed in this paper. Unlike most methods this approach retrieves information from a polygonal mesh via rasterization and extraction of silhouettes' continuous medial axes. Described method shows a great improvement in computational time comparing to existing methods. Method shows good extraction results for models with complex geometry and topology. Resulting curve-skeletons conform with most requirements to universal curve-skeletons.

International Symposium on Voronoi Diagrams in Science and Engineering, 2013

Trudy Meždunarodnoj konferencii po kompʹûternoj grafiki i zreniû "Grafikon", Nov 20, 2020

Аннотация. В статье описывается метод распознавания шрифтов на основе медиального представления, ... more Аннотация. В статье описывается метод распознавания шрифтов на основе медиального представления, интегрированный в систему распознавания шрифтов по цифровому изображению текста. Эта система ищет похожие шрифты, упорядоченные по схожести, на шрифт, изображенный на введенном пользователем изображении текста. Работа системы основана на решении двух задач машинного обучения: распознавания текста на изображении и распознавания шрифта по изображению текста. Для решения первой задачи используется понятие математической модели графемы, основанной на непрерывном медиальном представлении символа. Решение задачи распознавания шрифта основано на понятии морфологической ширины фигуры, также тесно связанной с медиальным представлением. Мы предлагаем метод использования функции морфологической ширины для поиска наиболее похожих шрифтов из известной базы. Проведенные эксперименты показывают высокую точность поиска наиболее похожих шрифтов. Для базы, состоящей из 2543 шрифтов, точность составляет 0.991 по метрике top@5 для правильно распознанного текста в размере шрифта 100 пикселей на изображении. Ключевые слова: графема, морфологическая ширина, цифровое изображение текста, цифровой шрифт, медиальное представление.

The Visual Computer, Mar 19, 2022

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, May 9, 2019

In this paper we solve the problem of finding the symmetry axis of the object in a digital binary... more In this paper we solve the problem of finding the symmetry axis of the object in a digital binary image. A new axial symmetry criterion is formulated for a connected discrete object. The problem of determining the symmetry measure and finding the symmetry axes arises in a variety of applications. In discrete images, exact symmetry is possible only in special cases. The disadvantage of the existing methods solving this problem is the high computational complexity. To improve computational efficiency, it is proposed to use the so-called Fourier descriptor. A new method for estimating the asymmetry of a discrete silhouette is proposed. The described algorithm for calculating the measure of asymmetry and determining the axis of symmetry is quadratic by the number of contour points. Methods for reducing the volume of calculations using a convex hull and taking into account the values of the modules of Fourier coefficients are proposed. Computational experiments are conducted with silhouettes of aircraft extracted from earth remote sensing images. The reliability of the described solution is established.

Oceanology, Sep 1, 2018

The chlorophyll a concentration (Cchl a) in the Sea of Azov is estimated by the two-band NIR-red ... more The chlorophyll a concentration (Cchl a) in the Sea of Azov is estimated by the two-band NIR-red algorithm [34] from MERIS images for 2002-2012. The sea-truth spectrophotometric measurements and MERIS remote estimates of Cchl a are compared. The monthly average Cchl a values are mapped from MERIS data for its lifetime for the first time. The features of the spatiotemporal distribution of Cchl a are ascertained. Differences between the seasonal dynamics of Cchl a in the Sea of Azov according to the literature data and the dynamics derived from MERIS data are found, namely: the summer-autumn phytoplankton growth period is longer than the spring period and is characterized by higher Cchl a values throughout the water area.

ECOLOGY ECONOMY INFORMATICS. Geoinformation technologies and space monitoring, 2018

Аннотация. В статье рассматривается задача подготовки обучающей выборки для алгоритмов сегментаци... more Аннотация. В статье рассматривается задача подготовки обучающей выборки для алгоритмов сегментации и классификации объектов заданной формы на аэрокосмических снимках. Предлагаемый подход основан на построении набора шаблонных векторных описаний объектов интереса. Непосредственная разметка снимков осуществляется оператором путем подгонки шаблонов к изображениям объектов. В качестве иллюстрации работы метода рассмотрена задача классификации самолетов на аэрокосмических снимках.

Proceedings of the 30th International Conference on Computer Graphics and Machine Vision (GraphiCon 2020). Part 1, 2020

In this article, a method of font recognition based on the medial representation, integrated into... more In this article, a method of font recognition based on the medial representation, integrated into the font recognition system based on a digital image of text is described. This system searches for similar fonts, ordered by similarity, to the font shown in the user-entered text image. The system is based on solving two machine learning problems: text recognition on an image and font recognition on a text image. To solve the first problem, we use the concept of a mathematical model of a grapheme based on a continuous medial representation of a symbol. The solution to the font recognition problem is based on the concept of the morphological width of the figure, which is also closely related to the medial representation. We propose a method for using the morphological width function to find the most similar fonts from a known database. The experiments show high accuracy of searching for the most similar fonts. For a database consisting of 2543 fonts, the accuracy is 0.991 according to ...

International Conference on Computer Vision Theory and Applications, 2009

This paper proposes a new estimation of facial asymmetry in 3D face models of humans and an algor... more This paper proposes a new estimation of facial asymmetry in 3D face models of humans and an algorithm to compute it. We consider models derived by 3D scanning method. Each model is given as a cloud of points in 3D space and can be considered as a discrete single-valued function of two variables. We present an approach for constructing a disparity measure between original face model and its reflected model. Main stages of proposed algorithm are construction Delaunay triangulations of two models and general Delaunay triangulation, function interpolation on basis of triangulations localization in each other and comparison of functions on separate triangles of general triangulation. Further using elementary manipulations of reflected model algorithm searches such position that two models constitute a maximum matching so that the corresponding disparity measure will be minimal. We carry out computing experiments on database consisting of about 200 face models. These experiments have indicated that the proposed estimation is stable for different models of one and the same person.

Restoration of spatial objects characteristics with locally symmetric elements is proposed in thi... more Restoration of spatial objects characteristics with locally symmetric elements is proposed in this paper. An approach based on the model of a spatial flexible object defined as a family of spheres with the centres on a graph with a tree-like structure is proposed. A method of real time identification of such objects using the stereo mate images of their silhouettes is introduced. Image processing comprises construction of continuous skeletons of silhouettes. Application to real time gesture recognition is considered.

We consider the problem of shape comparison for elastic objects presented by binary bitmaps. Our ... more We consider the problem of shape comparison for elastic objects presented by binary bitmaps. Our approach to similarity measuring of such objects is based on the conception of a flexible object. A flexible object is defined as a planar graph with a family of circles centered on graph edges. A set of admissible deformations is connected with each flexible object. These deformations are described as a group of planar graph vertices transforms. We define the flexible objects similarity through matching and alignment within the group of admissible deformations. The regular method for approximation of the binary bitmap shape by the flexible object is presented. The flexible object is designed as a subgraph of continuous skeleton of the binary bitmap. The proposed approach is applied to a problem of palm shape recognition for personal biometrical identification.