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Amjad Yousef El - Bahnasawi - One of the best experts on this subject based on the ideXlab platform.
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تمثيل الإطار الخارجي للكلمات العربية بكÙ�اءة من خلال الدمج بين نموذج الكنتور النشط وتØديد ونقاط الزوايا
الجامعة الإسلامية - غزة, 2017Co-Authors: Amjad Yousef El - BahnasawiAbstract:Graphical curves and surfaces fitting are hot areas of research studies and application, such as artistic applications, analysis applications and encoding purposes. Outline capture of digital word images is important in most of the desktop publishing systems. The Shapes of the characters are stored in the computer memory in terms of their outlines, and the outlines are expressed as Bezier curves. Existing methods for Arabic font outline description suffer from low fitting accuracy and efficiency. In our research, we developed a new method for outlining Shapes using Bezier curves with minimal set of curve points. A distinguishing characteristic of our method is that it combines the active contour method (snake) with corner detection to achieve an initial set of points that is as close to the Shape's boundaries as possible. The method links these points (snake + corner) into a compound Bezier curve, and iteratively improves the fitting of the curve over the actual boundaries of the Shape. We implemented and tested our method using MATLAB. Test cases included various levels of Shape complexity varying from simple, moderate, and high complexity depending on factors, such as: Boundary concavities, number of corners. Results show that our method achieved average 86% of accuracy when measured relative to true Shape Boundary. When compared to other similar methods (Masood & Sarfraz, 2009; Sarfraz & Khan, 2002; Ferdous A Sohel, Karmakar, Dooley, & Bennamoun, 2010), our method performed comparatively well. Keywords: Bezier curves, Shape descriptor, curvature, corner points, control points, Active Contour Model.تعتبر المنØنيات ÙˆØ§Ù„Ø£Ø³Ø·Ø Ø§Ù„Ø±Ø³ÙˆÙ…ÙŠØ© موضوعاً هاماً Ù�ÙŠ الدراسات البØثية ÙˆÙ�ÙŠ التطبيقات البرمجية مثل التطبيقات الÙ�نية، وتطبيقات تØليل وترميز البيانات. ويعتبر تخطيط الØدود الخارجية للكلمات عملية أساسية Ù�ÙŠ غالبية تطبيقات النشر المكتبي. Ù�ÙŠ هذه التطبيقات تخزن أشكال الأØرÙ� Ù�ÙŠ الذاكرة من Øيث خطوطها الخارجية، وتمثل الخطوط الخارجية على هيئة منØنيات Bezier. الطرق المستخدمة Øالياً لتØديد الخطوط الخارجية للكلمات العربية تنقصها دقة وكÙ�اءة الملاءمة ما بين الØدود الØقيقية والمنØنى الرسومي الذي تقوم بتشكيله. Ù�ÙŠ هذا البØØ« قمنا بتطوير طريقة جديدة لتخطيط الØدود الخارجية للكلمات تعتمد على منØنيات Bezier بمجموعة أقل من المنØنيات الجزئية. تتميز طريقتنا بخاصية مميزة وهي الدمج بين آلية لاستشعار الزوايا مع آلية نموذج الكنتور النشط (الأÙ�عى). يتم الدمج بين نقاط الزوايا ونقاط الأÙ�عى لتشكيل مجموعة موØدة من النقاط المبدئية قريبة قدر الإمكان من الØدود الØقيقية للشكل المراد تØديده. يتشكل منØنى Bezier من هذه المجموعة المدمجة، وتتم عملية تدريجية على دورات لملاءمة المنØنى على الØدود الØقيقية للشكل. قام الباØØ« بتنÙ�يذ وتجربة الطريقة الجديدة باستخدام برنامج MATLAB. وتم اختيار أشكال رسومية كعينات اختبار تتصÙ� بمستويات متباينة من التعقيد ØªØªØ±Ø§ÙˆØ Ù…Ø§ بين بسيط إلى متوسط إلى عالي التعقيد على أساس عوامل مثل تقعرات الØدود، عدد نقاط الزوايا، الÙ�تØات الداخلية، إلخ. وقد أظهرت نتائج الاختبار أن طريقتنا الجديدة Øققت دقة Ù�ÙŠ الملائمة تصل نسبتها إلى 86% مقارنة بالØدود الØقيقية للشكل المستهدÙ�. وكذلك Ù�قد كان أداء طريقتنا جيداً بالمقارنة مع طرق أخرى مماثلة
امجد يوس� البهنساوي - One of the best experts on this subject based on the ideXlab platform.
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تمثيل الإطار الخارجي للكلمات العربية بكÙ�اءة من خلال الدمج بين نموذج الكنتور النشط وتØديد ونقاط الزوايا
الجامعة الإسلامية - غزة, 2017Co-Authors: امجد يوسÙ� البهنساويAbstract:Graphical curves and surfaces fitting are hot areas of research studies and application, such as artistic applications, analysis applications and encoding purposes. Outline capture of digital word images is important in most of the desktop publishing systems. The Shapes of the characters are stored in the computer memory in terms of their outlines, and the outlines are expressed as Bezier curves. Existing methods for Arabic font outline description suffer from low fitting accuracy and efficiency. In our research, we developed a new method for outlining Shapes using Bezier curves with minimal set of curve points. A distinguishing characteristic of our method is that it combines the active contour method (snake) with corner detection to achieve an initial set of points that is as close to the Shape's boundaries as possible. The method links these points (snake + corner) into a compound Bezier curve, and iteratively improves the fitting of the curve over the actual boundaries of the Shape. We implemented and tested our method using MATLAB. Test cases included various levels of Shape complexity varying from simple, moderate, and high complexity depending on factors, such as: Boundary concavities, number of corners. Results show that our method achieved average 86% of accuracy when measured relative to true Shape Boundary. When compared to other similar methods (Masood & Sarfraz, 2009; Sarfraz & Khan, 2002; Ferdous A Sohel, Karmakar, Dooley, & Bennamoun, 2010), our method performed comparatively well. Keywords: Bezier curves, Shape descriptor, curvature, corner points, control points, Active Contour Model.تعتبر المنØنيات ÙˆØ§Ù„Ø£Ø³Ø·Ø Ø§Ù„Ø±Ø³ÙˆÙ…ÙŠØ© موضوعاً هاماً Ù�ÙŠ الدراسات البØثية ÙˆÙ�ÙŠ التطبيقات البرمجية مثل التطبيقات الÙ�نية، وتطبيقات تØليل وترميز البيانات. ويعتبر تخطيط الØدود الخارجية للكلمات عملية أساسية Ù�ÙŠ غالبية تطبيقات النشر المكتبي. Ù�ÙŠ هذه التطبيقات تخزن أشكال الأØرÙ� Ù�ÙŠ الذاكرة من Øيث خطوطها الخارجية، وتمثل الخطوط الخارجية على هيئة منØنيات Bezier. الطرق المستخدمة Øالياً لتØديد الخطوط الخارجية للكلمات العربية تنقصها دقة وكÙ�اءة الملاءمة ما بين الØدود الØقيقية والمنØنى الرسومي الذي تقوم بتشكيله. Ù�ÙŠ هذا البØØ« قمنا بتطوير طريقة جديدة لتخطيط الØدود الخارجية للكلمات تعتمد على منØنيات Bezier بمجموعة أقل من المنØنيات الجزئية. تتميز طريقتنا بخاصية مميزة وهي الدمج بين آلية لاستشعار الزوايا مع آلية نموذج الكنتور النشط (الأÙ�عى). يتم الدمج بين نقاط الزوايا ونقاط الأÙ�عى لتشكيل مجموعة موØدة من النقاط المبدئية قريبة قدر الإمكان من الØدود الØقيقية للشكل المراد تØديده. يتشكل منØنى Bezier من هذه المجموعة المدمجة، وتتم عملية تدريجية على دورات لملاءمة المنØنى على الØدود الØقيقية للشكل. قام الباØØ« بتنÙ�يذ وتجربة الطريقة الجديدة باستخدام برنامج MATLAB. وتم اختيار أشكال رسومية كعينات اختبار تتصÙ� بمستويات متباينة من التعقيد ØªØªØ±Ø§ÙˆØ Ù…Ø§ بين بسيط إلى متوسط إلى عالي التعقيد على أساس عوامل مثل تقعرات الØدود، عدد نقاط الزوايا، الÙ�تØات الداخلية، إلخ. وقد أظهرت نتائج الاختبار أن طريقتنا الجديدة Øققت دقة Ù�ÙŠ الملائمة تصل نسبتها إلى 86% مقارنة بالØدود الØقيقية للشكل المستهدÙ�. وكذلك Ù�قد كان أداء طريقتنا جيداً بالمقارنة مع طرق أخرى مماثلة.Bezier curvesShape descriptorcurvaturecorner pointscontrol pointsActive Contour Mode
Amiya Nayak - One of the best experts on this subject based on the ideXlab platform.
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Measuring conicity from Shape boundaries
2013Co-Authors: Milos Stojmenovic, Amiya NayakAbstract:There has been a lot of research on ellipse fitting and measuring ellipticity of a set of points. However, when the Shape is primarily hyperbolic or parabolic, there are no existing methods to measure such properties. This paper describes the first known methods of measuring conicity, hyperbolicity and parabolicity of a set of points. After finding the best conic fit, we measure the corresponding ellipticity (using a known method), hyperbolicity or parabolicity value with respect to that best fit. We are interested in measures which rely exclusively on Shape Boundary points. They should also be calculated very quickly, be invariant to rotation, scaling and translation. The evaluation of fits transforms the point data into polar representation where the radius in this representation is equal to the difference of distances from each point to both foci (for hyperbolas), and the sum of distances from each point to the focus and a line parallel to the directrix line (for parabolas). The linearity of the polar representation will correspond to the quality of the fit for the original data. The conicity measure is tested on a set of 45 Shapes.
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direct ellipse fitting and measuring based on Shape boundaries
Pacific-Rim Symposium on Image and Video Technology, 2007Co-Authors: Milos Stojmenovic, Amiya NayakAbstract:Measuring ellipticity is an important area of computer vision systems. Most existing ellipticity measures are area based and cannot be easily applied to point sets such as extracted edges from real world images. We are interested in ellipse fitting and ellipticity measures which rely exclusively on Shape Boundary points which are practical in computer vision. They should also be calculated very quickly, be invariant to rotation, scaling and translation. Direct ellipse fitting methods are guaranteed to specifically return an ellipse as the fit rather than any conic. We argue that the only existing direct ellipse fit method does not work properly and propose a new simple scheme. It will determine the optimal location of the foci of the fitted ellipse along the orientation line (symmetrically with respect to the Shape center) such that it minimizes the variance of sums of distances of points to the foci. We next propose a novel way of measuring the accuracy of ellipse fits against the original point set. The evaluation of fits proceeds by our novel ellipticity measure which transforms the point data into polar representation where the radius is equal to the sum of distances from the point to both foci, and the polar angle is equal to the one the original point makes with the center relative to the x-axis. The linearity of the polar representation will correspond to the quality of the ellipse fit for the original data. We also propose an ellipticity measure based on the average ratio of distances to the ellipse and to its center. The choice of center for each Shape impacts the overall ellipticity measure. We discuss two ways of determining the center of the Shape. The measures are tested on a set of Shapes. The proposed algorithms work well on both open and closed curves.
Milos Stojmenovic - One of the best experts on this subject based on the ideXlab platform.
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Measuring conicity from Shape boundaries
2013Co-Authors: Milos Stojmenovic, Amiya NayakAbstract:There has been a lot of research on ellipse fitting and measuring ellipticity of a set of points. However, when the Shape is primarily hyperbolic or parabolic, there are no existing methods to measure such properties. This paper describes the first known methods of measuring conicity, hyperbolicity and parabolicity of a set of points. After finding the best conic fit, we measure the corresponding ellipticity (using a known method), hyperbolicity or parabolicity value with respect to that best fit. We are interested in measures which rely exclusively on Shape Boundary points. They should also be calculated very quickly, be invariant to rotation, scaling and translation. The evaluation of fits transforms the point data into polar representation where the radius in this representation is equal to the difference of distances from each point to both foci (for hyperbolas), and the sum of distances from each point to the focus and a line parallel to the directrix line (for parabolas). The linearity of the polar representation will correspond to the quality of the fit for the original data. The conicity measure is tested on a set of 45 Shapes.
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measuring elongation from Shape Boundary
Journal of Mathematical Imaging and Vision, 2008Co-Authors: Milos Stojmenovic, Jovisa žunicAbstract:Shape elongation is one of the basic Shape descriptors that has a very clear intuitive meaning. That is the reason for its applicability in many Shape classification tasks. In this paper we define a new method for computing Shape elongation. The new measure is Boundary based and uses all the Boundary points. We start with Shapes having polygonal boundaries. After that we extend the method to Shapes with arbitrary boundaries. The new elongation measure converges when the assigned polygonal approximation converges toward a Shape. We express the measure with closed formulas in both cases: for polygonal Shapes and for arbitrary Shapes. The new measure finds the elongation for Shapes whose Boundary is not extracted completely, which is impossible to achieve with area based measures.
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direct ellipse fitting and measuring based on Shape boundaries
Pacific-Rim Symposium on Image and Video Technology, 2007Co-Authors: Milos Stojmenovic, Amiya NayakAbstract:Measuring ellipticity is an important area of computer vision systems. Most existing ellipticity measures are area based and cannot be easily applied to point sets such as extracted edges from real world images. We are interested in ellipse fitting and ellipticity measures which rely exclusively on Shape Boundary points which are practical in computer vision. They should also be calculated very quickly, be invariant to rotation, scaling and translation. Direct ellipse fitting methods are guaranteed to specifically return an ellipse as the fit rather than any conic. We argue that the only existing direct ellipse fit method does not work properly and propose a new simple scheme. It will determine the optimal location of the foci of the fitted ellipse along the orientation line (symmetrically with respect to the Shape center) such that it minimizes the variance of sums of distances of points to the foci. We next propose a novel way of measuring the accuracy of ellipse fits against the original point set. The evaluation of fits proceeds by our novel ellipticity measure which transforms the point data into polar representation where the radius is equal to the sum of distances from the point to both foci, and the polar angle is equal to the one the original point makes with the center relative to the x-axis. The linearity of the polar representation will correspond to the quality of the ellipse fit for the original data. We also propose an ellipticity measure based on the average ratio of distances to the ellipse and to its center. The choice of center for each Shape impacts the overall ellipticity measure. We discuss two ways of determining the center of the Shape. The measures are tested on a set of Shapes. The proposed algorithms work well on both open and closed curves.
Alastair R. Allen - One of the best experts on this subject based on the ideXlab platform.
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a polygonal approximation of Shape boundaries of marine plankton based on genetic algorithms
Journal of Visual Communication and Image Representation, 2016Co-Authors: John Watson, Alastair R. AllenAbstract:Abstract Polygonal approximation of a Shape Boundary can provide a minimalistic representation of the Shape. It can also accelerate the processing speed of feature extraction. Our interest is in applying such a method to approximate the boundaries of plankton Shapes. A polygonal approximation method based on genetic algorithms has been designed to compactly describe the plankton Shapes by polygons. Firstly, two artificial digital curves are used to test the performance of our algorithm. Results are compared with other existing algorithms which show that our algorithm has efficient performance for solving the problem of the polygonal approximation. Secondly, the proposed method is applied to a selection of plankton images under three different approximation levels to a polygonal fit and then five evaluation criteria are applied to determine which approximation level of a particular image is most suitable for describing the Shape. The stability and robustness of three approximation levels are also tested.