Symmetry and deformations of cluster and biomolecules by invariant shape coordinates

2021 ◽  
Author(s):  
Andrea Lombardi
Keyword(s):  
Invariant Shape

scholarly journals Blur-readable two-dimensional barcode based on blur-invariant shape and geometric features

2021 ◽  
Vol 18 (2) ◽  
pp. 172988142199958
Author(s):  
Shundao Xie ◽  
Hong-Zhou Tan
Keyword(s):  
Circular Disk ◽  
Geometric Features ◽  
Two Dimensional ◽  
Common Solution ◽  
Ringing Artifacts ◽  
2D Barcode ◽  
Defocus Blur ◽  
Blurred Image ◽  
Decoding Accuracy ◽  
Invariant Shape

In recent years, the application of two-dimensional (2D) barcode is more and more extensive and has been used as landmarks for robots to detect and peruse the information. However, it is hard to obtain a sharp 2D barcode image because of the moving robot, and the common solution is to deblur the blurry image before decoding the barcode. Image deblurring is an ill-posed problem, where ringing artifacts are commonly presented in the deblurred image, which causes the increase of decoding time and the limited improvement of decoding accuracy. In this article, a novel approach is proposed using blur-invariant shape and geometric features to make a blur-readable (BR) 2D barcode, which can be directly decoded even when seriously blurred. The finder patterns of BR code consist of two concentric rings and five disjoint disks, whose centroids form two triangles. The outer edges of the concentric rings can be regarded as blur-invariant shapes, which enable BR code to be quickly located even in a blurred image. The inner angles of the triangle are of blur-invariant geometric features, which can be used to store the format information of BR code. When suffering from severe defocus blur, the BR code can not only reduce the decoding time by skipping the deblurring process but also improve the decoding accuracy. With the defocus blur described by circular disk point-spread function, simulation results verify the performance of blur-invariant shape and the performance of BR code under blurred image situation.

scholarly journals An artificial immune system approach to automated program verification: Towards a theory of undecidability in biological computing

2017 ◽  
Author(s):  
Soumya Banerjee
Keyword(s):  
Immune System ◽  
System Approach ◽  
Artificial Immune System ◽  
Program Verification ◽  
Verification Task ◽  
Artificial Immune ◽  
Biological Computing ◽  
Robust Computation ◽  
Invariant Shape ◽  
Program Invariants

An immune system inspired Artificial Immune System (AIS) algorithm is presented, and is used for the purposes of automated program verification. Relevant immunological concepts are discussed and the field of AIS is briefly reviewed. It is proposed to use this AIS algorithm for a specific automated program verification task: that of predicting shape of program invariants. It is shown that the algorithm correctly predicts program invariant shape for a variety of benchmarked programs. Program invariants encapsulate the computability of a particular program, e.g. whether it performs a particular function correctly and whether it terminates or not. This work also lays the foundation for applying concepts of theoretical incomputability and undecidability to biological systems like the immune system that perform robust computation to eliminate pathogens.

scholarly journals Infants’ sensitivity to shape changes in 2D visual forms

2019 ◽  
Author(s):  
Moira Rose Dillon ◽  
Véronique Izard ◽  
Elizabeth Spelke
Keyword(s):  
Cognitive Science ◽  
Geometric Property ◽  
Relative Length ◽  
Dynamic Scenes ◽  
Visual World ◽  
Human Infants ◽  
Geometric Properties ◽  
Invariant Shape ◽  
Shape Changes

Research in developmental cognitive science reveals that human infants perceive shape changes in 2D visual forms that are repeatedly presented over long durations. Nevertheless, infants’ sensitivity to shape under the brief conditions of natural viewing has been little studied. Three experiments tested for this sensitivity by presenting 128 seven-month-old infants with shapes for the briefer durations under which they might see them in dynamic scenes. The experiments probed infants’ sensitivity to two fundamental geometric properties of scale- and orientation-invariant shape: relative length and angle. Infants detected shape changes in closed figures, which presented changes in both geometric properties. Infants also detected shape changes in open figures differing in angle when figures were presented at limited orientations. In contrast, when open figures were presented at unlimited orientations, infants detected changes in relative length but not in angle. The present research therefore suggests that, as infants look around at the cluttered and changing visual world, relative length is the primary geometric property by which they perceive scale- and orientation-invariant shape.

scholarly journals Adaptive locally affine-invariant shape matching

2018 ◽  
Vol 29 (4) ◽  
pp. 553-572 ◽  
Author(s):  
Smit Marvaniya ◽  
Raj Gupta ◽  
Anurag Mittal
Keyword(s):  
Shape Matching ◽  
Affine Invariant ◽  
Invariant Shape
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