This paper presents an algebraic technique for detecting the symmetry axes of a perspectively projected plane curve. The procedure applies to implicit polynomials which has been fitted to 2D image data acquired by means of a photo camera or a TV set. The effectiveness of the proposed method has been demonstrated experimentally by using both synthetic and real images.
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http://dx.doi.org/10.1109/TPAMI.2005.45 | DOI Listing |
Acc Chem Res
January 2025
School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
ConspectusSymmetry is a pervasive phenomenon spanning diverse fields, from art and architecture to mathematics and science. In the scientific realms, symmetry reveals fundamental laws, while symmetry breaking─the collapse of certain symmetry─is the underlying cause of phenomena. Research on symmetry and symmetry breaking consistently provides valuable insights across disciplines, from parity violation in physics to the origin of homochirality in biology.
View Article and Find Full Text PDFiScience
January 2025
Division of Optometry, Health Sciences, City University of London, London EC1V 0HB, UK.
A key property of our environment is the mirror symmetry of many objects, although symmetry is an abstract global property with no definable shape template, making symmetry identification a challenge for standard template-matching algorithms. We therefore ask whether Deep Neural Networks (DNNs) trained on typical natural environmental images develop a selectivity for symmetry similar to that of the human brain. We tested a DNN trained on such typical natural images with object-free random-dot images of 1, 2, and 4 symmetry axes.
View Article and Find Full Text PDFPlants (Basel)
December 2024
Co-Innovation Center of Sustainable Forestry in Southern China, College of Forestry and Grassland, Nanjing Forestry University, Nanjing 210037, China.
Our previous study using 41 tree rings of one Mill. disc indicated that the superellipse equation can accurately fit its tree-ring shape. This study further used the superellipse equation (xan+yβn=1 ) to model the geometries of 1090 tree rings of discs collected from five sites in Denmark.
View Article and Find Full Text PDFPLoS Pathog
December 2024
State Key Laboratory for Animal Disease Control and Prevention & National Data Center for Animal Infectious Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
The Very Low-Density Lipoprotein Receptor (VLDLR) is an entry receptor for the prototypic alphavirus Semliki Forest Virus (SFV). However, the precise mechanisms underlying the entry of SFV into cells mediated by VLDLR remain unclear. In this study, we found that of the eight class A (LA) repeats of the VLDLR, only LA2, LA3, and LA5 specifically bind to the native SFV virion while synergistically promoting SFV cell attachment and entry.
View Article and Find Full Text PDFPLoS Comput Biol
December 2024
Department of Mathematics, Northeastern University, Boston, Massachusetts, United States of America.
Symmetry breaking, which is ubiquitous in biological cells, functionally enables directed cell movement and organized embryogenesis. Prior to movement, cells break symmetry to form a well-defined cell front and rear in a process called polarization. In developing and regenerating tissues, collective cell movement requires the coordination of the polarity of the migration machineries of neighboring cells.
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