Papers by Panayiotis Rousopoulos
Abstract—In this paper a general methodology is introduced for the determination of potential pro... more Abstract—In this paper a general methodology is introduced for the determination of potential prototype curves used for the drawing of prehistoric wall-paintings. The approach includes a) preprocessing of the wall-paintings contours to properly partition them, according to their curvature, b) choice of prototype curves families, c) analysis and optimization in 4-manifold for a first estimation of the form of these prototypes, d) clustering of the contour parts and the prototypes, to determine a minimal number of potential guides, e) further optimization in 4-manifold, applied to each cluster separately, in order to determine the exact functional form of the potential guides, together with the corresponding drawn contour parts. The introduced methodology simultaneously deals with two problems: a) the arbitrariness in data-points orientation and b) the determination of one proper form for a prototype curve that optimally fits the corresponding contour data. Arbitrariness in orientatio...
Advanced Geometric Guides Were Used for the Drawing of Celebrated Late Bronze Age Wall Paintings
The present paper analyzes the contours of the painted figures encountered in celebrated prehisto... more The present paper analyzes the contours of the painted figures encountered in celebrated prehistoric frescoes, and it establishes that advanced geometric guides were used in the drawing of these wall paintings. Namely, analysis of the frescoes that decorated the edifice “Xeste 3” in the prehistoric settlement of Akrotiri, Thera showed that the artist or group of artists had used five geometric archetypes and five corresponding well-constructed stencils (four hyperbolae and one Archimedes’ spiral). The same analysis indicated that the distinctive Mycenaean fresco “Lady of Mycenae” has been generated using four geometric prototypes (two linear spirals and two hyperbolae), of the same classes with the ones of Akrotiri, but with different parameters. The methodology considers the longer segments of the prototype geometric shapes, which can be optimally matched with a small fitting error, to the contour of an already drawn figure. Equivalently, the method introduced by the authors determ...
Biocybernetics and Biomedical Engineering, 2016
One of the most prominent intellectual abilities of the human brain, which so far characterizes t... more One of the most prominent intellectual abilities of the human brain, which so far characterizes the human kind, is the process of logical reasoning/syllogism. Historically, one of the first philosophers, if not the first one, who tried to analyze logical reasoning by the means of deduction was Aristotle. According to his analysis, the reasoning process starts with two statements, i.e. ''All men are mortal''; ''All Athenians are men''. These two statements, in Aristotle's approach, lead to the conclusion that ''All Athenians are mortal'' with absolute certainty . We note that this Aristotle's syllogism, also known as valid reasoning, has been a very active, open field of research. Recently, a number of models have been proposed in order to encode and elucidate the underlying brain functions b i o c y b e r n e t i c s a n d b i o m e d i c a l e n g i n e e r i n g 3 6 ( 2 0 1 6 ) 2 9 2 -3 0 1 a r t i c l e i n f o Article history:
A very robust, fast, parallelizable adaptive least squares algorithm with excellent tracking abilities
Proceedings of ICASSP '94. IEEE International Conference on Acoustics, Speech and Signal Processing
In this paper a new computational scheme is introduced for performing recursive least squares ada... more In this paper a new computational scheme is introduced for performing recursive least squares adaptive filtering. The proposed algorithm is far more robust than all the already existing RLS schemes, in the sense that it is drastically less sensitive in the numerical error due to the finite precision with which all operations are executed. Hence, it has a lifetime tens of times greater than all the previous RLS schemes. Moreover, the algorithm introduced here has excellent tracking abilities and, due to its particular structure, it is parallelizable. When it is executed in parallel by four processors, it is faster than all the existing RLS algorithms, and in particular, it is by m steps faster, where m is the system order, than the FAEST and the FTF computational schemes
Pattern Recognition, 2013
In this paper, a novel approach is introduced for classifying curves into proper families, accord... more In this paper, a novel approach is introduced for classifying curves into proper families, according to their similarity. First, a mathematical quantity we call plane curvature is introduced and a number of propositions are stated and proved. Proper similarity measures of two curves are introduced and a subsequent statistical analysis is applied. First, the efficiency of the curve fitting process has been tested on 2 shapes datasets of reference. Next, the methodology has been applied to the very important problem of classifying 23 Byzantine codices and 46 Ancient inscriptions to their writers, thus achieving correct dating of their content. The inscriptions have been attributed to ten individual hands and the Byzantine codices to four writers.
A new approach for the identification of writers of important ancient documents
ABSTRACT In this paper, a novel approach is introduced for identifying the writer of a document, ... more ABSTRACT In this paper, a novel approach is introduced for identifying the writer of a document, with special emphasis to paleography. Towards this direction, a mathematical quantity called plane curvature is introduced and a number of associated propositions are stated. Proper similarity measures of two curves are defined and a subsequent statistical analysis is applied. The efficiency of the method has been, first, tested on a public reference database. The methodology has also been applied to the very important problem of classifying 23 Byzantine codices and 46 Ancient inscriptions to their writers, thus achieving correct dating of their content. The inscriptions have been attributed to ten individual hands and the Byzantine codices to four writers. Prominent epigraphologists and classicists fully agree with the obtained classification.
Abstract—A novel methodology is introduced here that exploits 2D images of arbitrary elastic body... more Abstract—A novel methodology is introduced here that exploits 2D images of arbitrary elastic body deformation instances, so as to quantify mechano-elastic characteristics that are deformation invariant. Determination of such characteristics allows for developing methods offering an image of the undeformed body. General assumptions about the mechano-elastic properties of the bodies are stated, which lead to two different approaches for obtaining bodies ’ deformation invariants. One was developed to spot deformed body’s neutral line and its cross sections, while the other solves deformation PDEs by performing a set of equivalent image operations on the deformed body images. Both these processes may furnish a body undeformed version from its deformed image. This was confirmed by obtaining the undeformed shape of deformed parasites, cells (protozoa), fibers and human lips. In addition, the method has been applied to the important problem of parasite automatic classification from their m...
Centaurus, 2005
The present paper offers strong evidence that there was a particularly advanced, for the era, sen... more The present paper offers strong evidence that there was a particularly advanced, for the era, sense and application of geometry in the prehistoric civilization of the island of Thera (Santorini), Greece, ca. 1650 BC. First, by applying an original method, it is demonstrated that specific shapes, depicted on so far unpublished wall paintings initially decorating the third floor of Xeste 3, correspond to advanced geometric configurations with remarkable accuracy. Thus, it is shown that there are configurations corresponding to linear spiral prototypes, others matching elliptical prototypes and sets of points lying on isogonal lines that are radii of regular polygons with 48, 32, and 24 angles. Subsequently, it is shown that the use of geometric archetypes for drawing played a prominent role in the Late Bronze Age Thera civilization. In fact, it is demonstrated that celebrated wall paintings have border lines that impressively match a limited number of linear (Archimedes') spirals, hyperbolas, and ellipses in a piecewise manner. This practically excludes the probability that these wall paintings were drawn by freehand, while, on the contrary, it strongly suggests that they were mainly drawn by means of geometric stencils.
Order to Determine the Method of Construction of Prehistoric Wall-Paintings
Abstract—In this paper a general methodology is introduced for the determination of potential pro... more Abstract—In this paper a general methodology is introduced for the determination of potential prototype curves used for the drawing of prehistoric wall-paintings. The approach includes a) preprocessing of the wall-paintings contours to properly partition them, according to their curvature, b) choice of prototype curves families, c) analysis and optimization in 4-manifold for a first estimation of the form of these prototypes, d) clustering of the contour parts and the prototypes, to determine a minimal number of potential guides, e) further optimization in 4-manifold, applied to each cluster separately, in order to determine the exact functional form of the potential guides, together with the corresponding drawn contour parts. The introduced methodology simultaneously deals with two problems: a) the arbitrariness in data-points orientation and b) the determination of one proper form for a prototype curve that optimally fits the corresponding contour data. Arbitrariness in orientatio...
2010 International Conference on Autonomous and Intelligent Systems, AIS 2010, 2010
In this paper a new approach is presented for automatic writer identification. The approach is ap... more In this paper a new approach is presented for automatic writer identification. The approach is applied to the identification of the writer of ancient Greek inscriptions that in turn may offer precise and objective dating of the inscriptions content. Such a dating is crucial for the correct history writing. The methodology is based on the idea of creating an ideal representative of each alphabet symbol in each inscription, via proper fitting of all realizations of the specific symbol in this inscription. Next, geometric features for the ideal representative for each alphabet symbol are defined and extracted and corresponding statistical processing follows based on the computation of the mean value and variance of these characteristics. The decision for writer identification is made via pair-wise, feature based comparisons of the ideal representatives of the inscriptions. Each comparison is implemented by means of multiple statistical tests and an introduced maximum likelihood approach. The system was applied to 33 Athenian inscriptions of classical era which were correctly attributed to 8 different hands, namely with 100% success rate.
Methods and Algorithms for the Automatic Identification of Writer of Ancient Documents
Determination of the method of construction of 1650 B.C. wall paintings
Abstract—In this paper, a methodology of general applicability is presented for answering the que... more Abstract—In this paper, a methodology of general applicability is presented for answering the question if an artist used a number of archetypes to draw a painting or if he drew it freehand. In fact, the contour line parts of the drawn objects that potentially correspond to archetypes are initially spotted. Subsequently, the exact form of these archetypes and their appearance throughout the painting is determined. Themethodhasbeenapplied to celebratedThera LateBronzeAgewall paintingswith full success. It has beendemonstrated that the artist or group of artists has used seven geometrical archetypes and seven corresponding well-constructed stencils (four hyperbolae, two ellipses, and one Archimedes ’ spiral) to draw the wall painting “Gathering of Crocus ” in 1650 B.C. Thismethod of drawing seems to be unique in the history of arts and of great importance for archaeology, and the history of mathematics and sciences, as well. Index Terms—Image line pattern analysis, archaeological image...
Archaeometry, 2006
This paper studies a set of wall-paintings of the Late Bronze Age (c. 1650 BC) initially decorati... more This paper studies a set of wall-paintings of the Late Bronze Age (c. 1650 BC) initially decorating the internal walls of the third floor of the edifice called 'Xeste 3', excavated at Akrotiri, Thera, whose restoration is now in progress. It deals with the methods used for the drawing of the geometrical figures appearing in these wall-paintings. It is demonstrated that most of the depicted configurations correspond with accuracy to geometrical prototypes such as linear spirals and canonical polygons. It is pointed out that the steady lines of the figures, their remarkable repeatability, the precision of the geometrical shapes and their even distribution in the wall-paintings indicate a very distinctive use of the 'Xeste 3' third floor, which is now investigated.
A new approach for the identification of writers of important ancient documents
Digital Signal Processing (DSP), 2013 18th International Conference on, Jul 2013
In this paper, a novel approach is introduced for identifying the writer of a document, with spec... more In this paper, a novel approach is introduced for identifying the writer of a document, with special emphasis to paleography. Towards this direction, a mathematical quantity called plane curvature is introduced and a number of associated propositions are stated. Proper similarity measures of two curves are defined and a subsequent statistical analysis is applied. The efficiency of the method has been, first, tested on a public reference database. The methodology has also been applied to the very important problem of classifying 23 Byzantine codices and 46 Ancient inscriptions to their writers, thus achieving correct dating of their content. The inscriptions have been attributed to ten individual hands and the Byzantine codices to four writers. Prominent epigraphologists and classicists fully agree with the obtained classification.
Proceedings Icip International Conference on Image Processing, Nov 1, 2009
In this paper a new general methodology is introduced for the determination of the method of cons... more In this paper a new general methodology is introduced for the determination of the method of construction of prehistoric wall-paintings. The approach consists of algorithms that perform a)preprocessing of the contours of the figures appearing in the wall-paintings, b)determination of pattern repetitions in the contours of the depicted entities, c)classification of these repeated patterns into proper geometric prototypes, d)curve fitting. By means of this methodology, the authors demonstrated that a number of wall-paintings excavated at Mycenae and in Aegean islands, made before the 13th century B.C., were drawn via the use of guides. These stencils -guides were very precise geometric figures and in particular linear spirals and hyperbolae, thus indicating knowledge of constructing these complicated schemes more than 1000 years before the appearance of Classical Age mathematics.
Antiquity, 2008
A research team at Akrotiri, Thera, here examine the Bronze Age frescoes and show that the artist... more A research team at Akrotiri, Thera, here examine the Bronze Age frescoes and show that the artists were making use of templates of well known geometric curves. Some of the spirals, hyperbolae and ellipses which all feature in the repertoire do not occur in nature and must have their origin in some still unknown human science or aesthetic.
International Journal of Imaging
In this paper two approaches of general applicability for placing fragments of important archeolo... more In this paper two approaches of general applicability for placing fragments of important archeological objects in their proper position are presented. Both methods are based on the thematic content of the drawings depicted on fragments of c.1650 B.C. wall-paintings, excavated at Akrotiri of the Greek island of Thera. The first method employs the statistical nature of the drawn figures’ dimensions and gives an estimate of the probability that two fragments belong to the same decorative element and are properly placed in it. During the second method, the authors exploit the fact that the contour lines of many drawn objects correspond to specific geometric archetypes. Subsequently, an exhaustive Least Squares novel approach is applied in order to correctly place fragments containing broken contour lines of the same decorative elements. Both methods have been successfully applied to the restoration of various fragmented wall-paintings. The methods are particularly useful in cases where ...
An Overview of Methods for Automatic Reassembly of Fragmented Objects
Mathematical and Computational Solutions for Archaeology, 2012
Antiquity, 2008
A research team at Akrotiri, Thera, here examine the Bronze Age frescoes and show that the artist... more A research team at Akrotiri, Thera, here examine the Bronze Age frescoes and show that the artists were making use of templates of well known geometric curves. Some of the spirals, hyperbolae and ellipses which all feature in the repertoire do not occur in nature and must have their origin in some still unknown human science or aesthetic.
In this work a new methodology is introduced for the automated reassembling/reconstruction of fra... more In this work a new methodology is introduced for the automated reassembling/reconstruction of fragmented objects using their 3D digital representation. The whole process starts by 3D scanning of the available fragments. These are subsequently properly processed and the obtained fragments' 3D images are automatically tested for possible matching, by means of five novel introduced criteria. The first criterion considers the volume of the gap between two properly placed fragments. Two more criteria consider the fragments' overlapping in each possible matching position. Finally, criteria 4, 5 employ principles from calculus of variations to obtain bounds for the area of the contact surfaces and the length of contact curves. The method has been applied with great success both in the reconstruction of an object artificially broken by the authors and, most important, in the virtual reassembling of parts of wallpaintings made before 1100 BC., excavated highly fragmented in Mycenae and Tiryntha, Greece.
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Papers by Panayiotis Rousopoulos